Search

Western Yunnan is an important area for Mesozoic marine strata, development of which helps to reconstruct paleoenvironments in the eastern Tethys. To bring knowledge of eastern Tethys up to that of western Tethys, this study focuses on its sedimentary characteristics and paleoenvironmental significance concentrating on the Xiushan section of the Simao Basin with analyses of the petrology, element geochemistry, and C‐O‐Sr isotopes. Samples are micrite, bioclastic limestone, marl, and mixed calcareous clastic rocks with the 87Sr/86Sr values of limestone ranging from 0.708255 to 0.708933; the δ13C values of the limestone range from –5‰ to +1.5‰ and the δ18O values range from –13.7‰ to –9.1‰. Based on the results, it is concluded that the Middle Jurassic limestones in the Simao Basin were deposited in a tidal flat environment with a strong influence of terrigenous input. At least one transgression event occurred during the depositional period. The paleoclimate as a whole changed from dry hot to humid hot and back to dry hot again. These enriched and improved results provide further data support for a comparison of the paleoenvironments between the eastern and western Tethys. [ABSTRACT FROM AUTHOR]

Permian sedimentary successions, widely distributed in the eastern Junggar Basin, may record key details on the closure of the Paleo‐Asian Ocean in this region. Results of boreholes show that Permian strata is mainly composed of mudstone, sandy mudstone, siltstone, sandstone, sandy conglomerate, dolomite, and limestone. Detrital zircon U‐Pb dating results of three sandstone samples yielded the calculated maximum ages of 296 Ma, 278 Ma and 293 Ma, indicating they possibly deposited during the Early Permian. Permian strata in the eastern Junggar Basin show similar rock associations and detrital zircon age data distribution patterns. Our new and compiled age data for sandstone samples in the eastern Junggar Basin and Bogda region yield predominant Paleozoic ages, close to their sedimentary ages. Such detrital zircon age data distribution patterns support the hypothesis that these Early Permian meta‐clastic rocks in the eastern Junggar Basin and Bogda region were deposited in a subduction‐related basin, and indicate an Early Permian Ocean prevented Precambrian detritus from the Central Tianshan block from depositing in the eastern Junggar Basin and Bogda region. [ABSTRACT FROM AUTHOR]

The results of a comparison of various ratios of trace elements-indicators of the composition of provenances for clay rocks of the Middle Riphean Avzyan Formation and the Upper Riphean Biryan Subformation of the Zilmerdak Formation (Bashkirian meganticlinorium, Southern Urals) are analyzed. The formation of these two objects is separated by a hiatus, with the maximum duration up to 250 Ma. The study is based on materials related to the content of trace elements in clay/fine-grained clastic rocks, respectively, of the Avzyan Formation (28 samples) and Biryan Subformation (16 samples) from the collections of E.Z. Gareev and the author, obtained by the ICP-MS method at the IGG Ural Branch of the Russian Academy of Sciences (Yekaterinburg). Distribution of individual and average data points of clay rocks of the named objects on La/Sc–Th/Co, Sc–Th/Sc, Eu/Eu*–Th/Sc, Ni–V–10Th, Th–La–Sc, Y/Ni–Cr/V, Cr/Th–Th/Sc, and Hf–La/Th diagrams are significantly comparable. The chondrite-normalized spectra of rare earth elements (REE) are also comparable. Only on the Th–Th/U diagram, the distribution of data points has a slightly different form, suggesting that either the provenance composition was invariable for almost 250 Ma, the duration of the pre-Upper Riphean hiatus was not so long, the author's analytics are "lame", or there are other reasons. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Carboniferous Benxi Formation in southern Shanxi of North China has significant bauxite resource potential; however, the source of its metallogenic material and its sedimentary environment remain unclear. The microscopy, X-ray diffraction, X-ray fluorescence spectroscopy, and inductively coupled plasma mass spectrometry methods were applied in this study to examine the mineralogical, petrographic, and geochemical characteristics. Geochemical proxies of La/Y, Sr/Ba, Al2O3/TiO2, Zr/Sc, Th/Sc, La/Sc, and Th/Co were analyzed to investigate the paleo-depositional environment and provenance of the aluminum-bearing strata. The findings indicate that diaspores are the primary ore minerals in bauxite, while kaolinite and rutile are the predominant gangue minerals. Both the bauxite and claystone/aluminous rocks exhibit high enrichment in Li, Bi, and U, with relative enrichment in In, Sb, Th, Nb, and Ta. Li is notably concentrated in the claystone/aluminous rocks, reaching up to 1994.00 μg/g, primarily occurring in cookeite and boehmite, while U is highly concentrated in the bauxite. The aluminum-bearing strata were primarily formed under alkaline-reducing conditions, with changes in acidity and alkalinity of the environment during the sedimentary diagenetic process. Marine transgressions significantly impacted the sedimentary environment of the aluminum-bearing strata, and the paleoclimate was characterized as hot and humid. The principal factors contributing to enrichment of aluminum in the sedimentary basin were the in situ weathering of aluminum-rich source rocks and the transport of clastic materials from high-aluminum source rocks. The source rocks were closely associated with intermediate-acidic magmatic rocks and potentially related to the weathering of Ordovician carbonates. [ABSTRACT FROM AUTHOR]

The Upper Permian Wujiaping (WJP) Formation in the Yangtze Block (Southern China) has great potential for shale gas exploration. However, the sedimentary characteristics and environmental evolution of the WJP Formation are poorly understood. Based on 260 hand specimen samples obtained from 18 sections and 1 borehole in the eastern Yangtze Block, petrographic observations reveal that the WJP Formation is composed of 11 rock types. Combined with analyses of geochemical compositions, the sedimentary facies belts of the WJP Formation are divided into shoreland, shallow-water shelf, deep-water shelf shoal, restricted platform, and open platform. Bauxite was developed in the shoreland at the bottom of the WJP Formation, which is attributed to the Dongwu movement. The formation of paleo-uplift exerted a significant effect on paleogeomorphology and led to a major change in the sedimentary model from the underlying stratum to the WJP Formation. During the lower WJP Formation sedimentary period, gradual transgression occurred in the eastern Yangtze Block, and the lithology was mainly composed of clastic rocks. Shoreland, shallow-water shelf, and deep-water shelf were developed northeastward in turn. In the period of the upper WJP Formation, due to durative transgression, the area of the shoreland reduced southwestward. The lithology converted from clastic rocks into carbonates, and the restricted platform and open platform were developed northeastward. A few patched shoals formed in the restricted platform. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Recovery Efficiency is the property of Petroleum Geology & Recovery Efficiency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Mars 2020 Perseverance rover discovered fine‐grained clastic sedimentary rocks in the "Hogwallow Flats" member of the "Shenandoah" formation at Jezero crater, Mars. The Hogwallow Flats member shows evidence of multiple phases of diagenesis including Fe/Mg‐sulfate‐rich (20–30 wt. %) outcrop transitioning downward into red‐purple‐gray mottled outcrop, Fe/Mg clay minerals and oxides, putative concretions, occasional Ca sulfate‐filled fractures, and variable redox state over small (cm) spatial scales. This work uses Mastcam‐Z and SuperCam instrument data to characterize and interpret the sedimentary facies, mineralogy and diagenetic features of the Hogwallow Flats member. The lateral continuity of bedrock similar in tone and morphology to Hogwallow Flats that occurs over several km within the western Jezero sedimentary fan suggests widespread deposition in a lacustrine or alluvial floodplain setting. Following deposition, sediments interacted with multiple fluids of variable redox state and salinity under habitable conditions. Three drilled sample cores were collected from this interval of the Shenandoah formation as part of the Mars Sample Return campaign. These samples have very high potential to preserve organic compounds and biosignatures. Drill cores may partially include dark‐toned mottled outcrop that lies directly below light‐toned, sulfate‐cemented outcrop. This facies may represent some of the least oxidized material observed at this interval of the Shenandoah formation. This work reconstructs the diagenetic history of the Hogwallow Flats member and discusses implications for biosignature preservation in rock samples for possible return to Earth. Plain Language Summary: The Mars 2020 Perseverance rover discovered sedimentary rocks in Jezero crater during the second year of its mission. Some of these rocks were informally named the "Hogwallow Flats" member of the "Shenandoah" formation. These rocks contain abundant clay minerals and sulfates, indicating ancient interactions with liquid water. They may preserve organic matter and signs of life that could tell us whether life was ever present in Jezero crater billions of years ago. The sediments here appear to have undergone physical and chemical changes after deposition—called diagenesis—when interacting with liquid water. These changes, which may have occurred in a lake or a shallow river plain and later when the sediments were shallowly buried, are often associated with favorable conditions for preserving signs of ancient life. However, these changes may also have resulted in the breakdown of these signs of life. This work reconstructs the geologic history of the Hogwallow Flats member and discusses the importance of these rocks for the search for ancient life on Mars. A total of three rock cores were collected by Perseverance from these rocks for return to Earth. These samples have very high potential to preserve organic matter and signs of ancient life. Key Points: Fine‐grained clastic sedimentary rocks at the Hogwallow Flats member underwent limited diagenesisDiagenesis may have occurred in a lake or a shallow river plain and later when the sediments were shallowly buriedMottling features, sulfates and clay minerals within drilled rock core samples for Mars Sample Return have high astrobiological potential [ABSTRACT FROM AUTHOR]

This study presents a comprehensive characterization of the Neogene-Quaternary formations within the offshore Temsah gas field, which is approximately 65 km NNW of Port Said offshore the Nile Delta Basin. By integrating seismic and well log data, we constructed a detailed static reservoir model to address the complex geological structures and evaluate hydrocarbon potential. The Temsah offshore gas field has a complex geological structure characterized by numerous normal faults aligned in the two fault systems one northeast-southwest and another northwest-southeast trending. The predominance of clastic rocks and petroleum system setting in the Nile Delta Basin make this location favourable for hydrocarbon accumulations. Utilizing data from four wells and twenty-nine seismic lines, an in-depth interpretation was conducted to overcome the challenge of precise seismic feature delineation. Static reservoir model incorporates detailed three-dimensional visualizations of sandstones and shale layers, with a particular focus on the Upper Sandstone of Kafr El-Sheikh and Sidi Salem formations. Detailed three-dimensional model illustrated the structural impact on the studied reservoirs. Shale volume, water saturation property distribution grids complemented a constructed 3D model depicting the spatial distribution of rock facies and petrophysical parameters within the Temsah gas field. The integrated approach facilitated the identification and evaluation of three hydrocarbon prospect locations with estimated Gas Initially In Place (GIIP) ranging from approximately 2,856,782 Billion Cubic Feet [BCF] to 5,332,660 [BCF]. These findings underscore the substantial potential for advancing field development in the Temsah gas field. [ABSTRACT FROM AUTHOR]

The Carboniferous strata in the northeastern Junggar Basin are an important exploration field for natural gas in the basin. However, volcanic rocks have long been the primary exploration target. In contrast, the exploration and research of clastic rocks associated with source formations have been largely overlooked, resulting in an insufficient understanding of the reservoir forming conditions and exploration potential of Carboniferous clastic rocks. Through the evaluation of Carboniferous source rocks, effective source stove characterization, clastic reservoir evaluation, oil and gas source correlation, and reservoir formation model construction in this region, three key findings have been made. First, the Carboniferous in the northeastern Junggar Basin has developed three sets of high-quality gas source rocks: the Dishuiquan Formation, the Songkalsu B Member, and the Shiqiantan Formation. These formations correspond to three hydrocarbon source centers: the Sannan--Dishuiquan Sag, the Wucaiwan Sag--Dajing area, and the Dongdao Haizi Sag--Baijiahai High. Second, the Carboniferous system in the northeast has developed multiple types of large-scale reservoirs, including sand conglomerates, sandstones, turbidites, dolomitic rocks, and shale. These reservoirs are generally characterized by low porosity to ultra-low porosity and low permeability to ultra-low permeability reservoirs. There is a dissolution pore development zone at depths of 2900-4500 m. Third, a comparison of oil and gas sources reveals that all three sets of gas source rocks contribute to the natural gas found in the northeast, with obvious characteristics of near-source reservoir formation. The Carboniferous clastic rocks host two types of natural gas reservoirs: unconventional and conventional near-source reservoirs. It is predicted that there is an orderly accumulation pattern of shale gas, tight sandstone gas, and conventional natural gas reservoirs. This study reveals that the Carboniferous clastic rock source and reservoir configuration in the northeastern Junggar Basin is highly favorable, and the natural gas reservoirs in source and near-source clastic rocks represent important exploration directions. [ABSTRACT FROM AUTHOR]

Many of the CM carbonaceous chondrites are regolith breccias and so should have abundant evidence for collisional processing. The constituent clasts of these fragmental rocks frequently display compactional petrofabrics; yet, olivine microstructures show that most CMs are unshocked. To better understand the reasons for this contradiction, we have sought other evidence for hypervelocity impact processing of CM chondrites using the Cold Bokkeveld meteorite. We find that this regolith breccia contains rare particles of vesicular shock melt that are close in chemical composition to bulk CM chondrite. Transmission electron microscopy of a melt bead shows that it is composed of silicate glass with inclusions of pentlandite, pyrrhotite, and wüstite. Characterization of shards of another bead by atom probe tomography reveals nanoscale clusters of sulfur that represent sulfide inclusions arrested at an early stage of growth. These glass particles are mineralogically comparable to micrometeoroid impact melt described from the Cb‐type asteroid Ryugu and melt that has been experimentally produced by pulsed laser irradiation of CM targets. The glass could have formed by in situ shock‐melting, but petrographic evidence is more consistent with an origin as ballistic ejecta from a distal impact. The scarcity of melt in this meteorite, and CM chondrites more broadly, is consistent with the explosive fragmentation of hydrous asteroids following energetic collisions. Cold Bokkeveld's parent body is likely to be a second‐generation asteroid that was constructed from the debris of one or more earlier bodies, and only a small proportion of the reaccreted material had been highly shocked and melted. [ABSTRACT FROM AUTHOR]

On the basis of data on the geochemical characteristics ((La/Yb)N, Eu/Eu*, and content of Th) of clay rocks of Podolian Transnistria, Southeastern Poland, Belarus and Volyn, Lithuania, the vicinity of St. Petersburg, Southeastern White Sea region, and Arctic Norway, categories of rivers that transported fine-grained aluminosilicate clastic material to sinks that existed during the Vendian and Early Cambrian were reconstructed in the west of the East European Platform. The distribution of data points of clay rocks of the Volhynian time on the (La/Yb)N–Eu/Eu* diagram with the fields of the composition of the pelitic fraction of bottom sediments in the mouth of modern rivers of various categories allows us to assume that, for Lithuania and Podolian Transnistria, the feeding provinces were, among other things, paleowatersheds composed of volcanic formations. For Eastern Belarus and the Southeastern White Sea region, the influence of erosion products supplied by rivers flowing through igneous/metamorphic terranes (crystalline basement) is noticeable. A significant part of the clastic material was carried by rivers that drained sedimentary formations, as well as large rivers, i.e., rivers whose length exceeded 1000 km and whose drainage area was more than 100 000 km2. The existence of the latter is confirmed by the presence of detrital zircon in the rocks of the Zhukov Formation of Southeastern Poland, borrowed possibly from the rocks of Fennoscandia. In the Redkinian time, along with large rivers (rivers of category 1) and rivers fed by the products of erosion of sedimentary formations (rivers of category 2), transport of fine-grained clastic rocks was also carried out by rivers that drained rocks of the crystalline basement (rivers of category 3; this is typical of Belarus and Volyn, the Southeastern White Sea, and Arctic Norway) and by rivers flowing through areas of distribution of volcanic associations (rivers of category 4). The distribution of data points of the clay rocks of the Kotlin stage on the (La/Yb)N–Eu/Eu* diagram suggests that the main agents of transport of fine-grained aluminosilicate clastic material to sinks at that time were large rivers and rivers fed by fine-grained particulate matter owing to the erosion of predominantly sedimentary rocks. The Early Cambrian paleowatersheds were apparently composed not only of crystalline rocks but also of sedimentary formations. All of the above is in fairly good agreement with the previously established fact of a gradual increase in the contribution of erosion products of sedimentary rocks to the formation of Vendian–Early Cambrian sedimentary sequences from Podolian Transnistria to Arctic Norway. [ABSTRACT FROM AUTHOR]

This paper completes the examination of results of the study of lithogeochemical characteristics of a pilot collection of the Riphean–Vendian sandstones, siltstones, and claystones (last one based on the interpretation of results) in Belarus. Data on the age of detrital zircon published in recent years suggest that Upper Precambrian rocks of this region were sourced from the Osnitsk–Mikashevichi and the Trans-Scandinavian igneous belts, the Volyn–Brest large igneous province, rapakivi granites, as well as various rock associations of Sarmatia, Danopolonian orogen and Svecofennides. Based on the lithogeochemical characteristics, the distribution of data points of the studied clastic rocks on discriminant diagrams provides insight into the possible provenance, paleogeodynamic, paleogeographic, and paleoclimatic settings and suggests several conclusions. The considered Riphean–Vendian stratons in Belarus are composed mainly of erosion products of within-plate granitoids, as well as various island-arc and syncollisional felsic igneous rocks. The share of erosion products of mafic rocks among them generally does not exceed 30%. It is significant mainly in the Volyn Group rocks (erosion products of the Volyn–Brest large igneous province), as well as in some samples of the Nizov, Selyavy, and Kotlin formations (fragments of mafic rocks from other provenances?). The source-to-sink transport was accomplished mainly by large rivers. Paleogeodynamic settings varied from quite active to quite passive. The paleoclimate in catchment areas was most likely arid/semiarid in the Riphean. In the Vendian, it was humid and varied from subtropical in the Early Vendian (except the Glusk Formation) to tropical in the Late Vendian. The obtained results also make it possible to show some peculiarities of the known methods and techniques of paleoclimate reconstruction. [ABSTRACT FROM AUTHOR]

Wide azimuth seismic data play an important role in deep reservoir prediction. According to the Paleogene clastic rock reservoir prediction, the high‐density and wide azimuth 3D seismic data acquisition of ocean bottom nodes was first carried out in a Chinese offshore oilfield in 2019. After high precision amplitude‐preserving processing, we obtained the high‐quality wide azimuth gathers. However, the research on anisotropy and reservoir prediction using wide azimuth seismic data mainly focuses on carbonate and bedrock intervals, which is not suitable for clastic rock reservoir prediction. Therefore, this paper innovatively proposes a clastic rock reservoir prediction method, which studies prestack reservoir prediction in the ray parameter domain based on wide azimuth ocean bottom node seismic data. Based on the azimuth gathers, we can obtain elastic parameters through prestack amplitude versus offset inversion, which is used to characterize the reservoir, so it is significant to obtain high precision elastic parameters in order to get highly reliable reservoir prediction results. In this paper, we develop an amplitude versus offset inversion method based on the Bayesian theory in ray parameter domain, the output of which is density, P‐wave impedance and Vp/Vs. These elastic parameters have high precision, and density data are valuable input for reservoir characterization because they are sensitive to the lithology of clastic rock reservoir at different orientations. In ray parameter domain inversion, the ray path of seismic wave propagation is considered polyline, which is more consistent with the actual situation; thus, extracted amplitudes of P gathers used in inversion are more accurate. In addition, the reflection coefficient formula in ray parameter domain has higher precision when the incident angle is large. The inversion based on the Bayesian theory can improve the stability of the inversion. Test on the actual data shows that the result of ray parameter domain inversion with a Bayesian scheme is more accurate, stable and reliable. Based on the above high precision density inversion results, an innovative wide azimuth data reservoir prediction technology based on elliptical short‐axis fitting was proposed. The actual prediction of the deep reservoir in the Bohai oilfield shows that sand thickness fitting prediction results in the short axis can best match the actual drilling sandstone thickness. The coincidence rate is 86% and the short‐axis fitting results are more in agreement with geological laws. Theoretical research and practical applications have shown that this method is feasible and effective, with high prediction accuracy, computational efficiency and strong application value. [ABSTRACT FROM AUTHOR]

The Neoarchaean Belingwe greenstone belt of the Zimbabwe craton consists of a well-preserved succession of rocks of low metamorphic grade and low strain. We present new age constraints for the Ngezi Group of the belt and discuss them in the light of greenstone belt evolution. We propose crustal destabilization of the Zimbabwe proto-craton as a result of a global flare of mantle-derived magmatism at ~ 2.75 Ga. This gave rise to extension of a Mesoarchaean granitoid-greenstone terrain, rapid subsidence and, initially, deposition of a transgressive cover succession (Manjeri Formation). High degrees of stretching of proto-cratonic and mantle lithosphere provided accommodation space for the emplacement of several kilometres of submarine volcanic rocks on deeply submerged granitoid-greenstone basement, herein referred to as proto-cratonic flood basalts. Once extension and magmatism had ceased, chemical and clastic sedimentary rocks of the Cheshire Formation were deposited prior to 2.71 Ga as a result of, and subjected to, compressional deformation, and much earlier than previously assumed. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Geoscience is the property of Natural Gas Geoscience and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to clarify the response relationship between rocky desertification and land use under different lithology background in karst area. We obtained the land use distribution in 2005, 2010 and 2015 by using supervised classification, and then carried out superimposed analysis with the rocky desertification and lithology data in the same period. The result shows that woodland and shrubbery are mainly distributed on limestone interbedded with clastic rock, with an area of approximately 51.73 km2. Grasslands and arable land are mainly distributed on continuous limestone and limestone interbedded with clastic rock. Rocky desertification area in the limestone interbedded with clastic rock is the largest, and extremely severe rocky desertification (ESKRD) of 6.70 km2, due to the difference of lithologic types. Different levels of rocky desertification are correlated with different land use types and lithology types. The type of rocky desertification in forest land is mainly light rocky desertification (LKRD), contributing more than 40% of the area of rocky desertification, while the type of severe rocky desertification (SKRD) is mainly distributed in cultivated land, contributing more than 20% of the area of rocky desertification. In addition, due to the limited available resources in karst mountain areas, rocky desertification caused by human activities may also occur on non-carbonate rocks. We have emphasized the quantitative analysis of the response relationship between rocky desertification and land use at spatial grid scale, which is of great value for the location and treatment of rocky desertification in karst areas. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi Journal of Chemical & Petroleum Engineering is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Excavation in deep weak rock engineering can significantly alter the stress state in the surrounding rock, often leading to varying degrees of floor heave. The excavation stress paths from the immediate floor to the interior floor were determined by simulating tunnel excavation and monitoring stress changes at fixed points on the floor. The characteristic stresses, failure modes, acoustic emission and deformation features of three types of clastic rock under excavation stress paths were experimentally investigated to reveal the floor heave mechanism. The study found that as the distance from the excavation boundary increased, the bearing capacity of the clastic rock gradually enhanced, and the risk of macroscopic failure decreased, transitioning from tensile failure to tensile–shear mixed failure. Simultaneously, the excavation-induced dilational deformation rapidly decreased. A novel method was proposed to evaluate the dilational deformation of surrounding rock induced by excavation based on the strain features of the samples under the different stress paths. The results demonstrated a rapid decrease in dilational deformation from the immediate floor to the interior floor for the three types of surrounding rock, with the maximum total dilation and the greatest risk of floor heave observed in contact cementation surrounding rock. Finally, the floor heave mechanisms of three types of clastic rock were summarized as follows: unloading dilation combined with macroscopic failure; slight rebound of the immediate floor coupled with multiple microcracks; notable rebound of the immediate floor accompanied by few microcracks. This study provides new insights into the mechanics disasters and selection of support measures for deep-buried tunnels. Highlights: Experiments were conducted on three types of clastic rock under excavation stress paths from the immediate floor to the interior floor. The characteristic stress, failure mode, AE characteristics and deformation behavior induced by excavation of three types of clastic rock were studied. A method was proposed to evaluate the dilational deformation of surrounding rock induced by tunneling. The floor heave mechanisms of three types of clastic rock were revealed. [ABSTRACT FROM AUTHOR]

Identifying source orogens for syn-orogenic sediments in dispersed fragments of a supercontinent provides key information on the tectonic evolution of the orogens involved in supercontinent assembly and on paleogeographic reconstruction. An approach using U-Pb geochronology and trace elements of multiple detrital minerals including zircon, rutile, apatite, and monazite has major advantages over detrital zircon studies alone. Application of this multi-pronged approach to Ediacaran and Cambrian clastic sedimentary rocks from the West Cathaysia terrane of the South China block demonstrates that these rocks were deposited in two distinct, but overlapping, syn-orogenic basins related to the assembly of eastern Gondwana. The Ediacaran rocks have detritus likely sourced from the Paterson Petermann orogen (PPO) in Australia, and the dominant 650–600 Ma populations and trace element compositions of detrital rutile and apatite indicate a significant Ediacaran thermal and high-pressure metamorphic event in the orogen. The appearance of Cambrian and Tonian detrital rutile and apatite populations in the Cambrian rocks indicates derivation from a different source orogen characterized by multiple thermal events, most likely the Kuunga-Pinjarra orogen (KPO). Our data suggest that West Cathaysia was located adjacent to both the PPO and the KPO and support the hypothesis that the PPO was a collisional, rather than a long-lived post-Grenvillian intraplate, orogen. Our data also suggest a poly-metamorphic history for the poorly preserved northern part of the KPO and a larger expanse of Greater India. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Diagenetic physical simulation is a reliable means to study patterns of pore evolution and variations of physical properties, however, the current compaction model is mostly based on sandstone, and there is a lack of quantitative compaction and porosity reduction studies for more complex rock fabrics. In order to simulate the continuous change of intergranular porosity in the reservoir under compaction during the diagenesis of buried sedimentary strata, a self-designed diagenesis simulation experimental system was adopted. Using different modern sediment samples, the simulation experiment of mechanical compaction of glutenite was carried out. The experiment shows that during the process of mechanical compaction of glutenite, the change of porosity with depth is segmented, and there is a good logarithmic relationship between depth and porosity in the process of diagenetic compaction. The larger the grain size in the reservoir rock, the better the pore preservation capacity; When the sand particles fill the pores among gravel, stable secondary support structure formed by gravel and sand grades can effectively take over the bearing pressure, and when the sand-grade particle content is about 30%, the pressure-bearing capacity is the strongest; Intergranular heterobase filling is greater in samples with high heterobase content, high heterobasic content is not favourable to the preservation of primary pores. This study provides favorable experimental support for the preservation mechanism of deep clastic reservoir pores, and has important theoretical and practical significance for oil and gas exploration in the study area. The use of simulation experiment provides a useful idea for the evaluation and prediction of reservoirs and the search for favorable reservoir development zones in the future. [ABSTRACT FROM AUTHOR]

Radiogenic isotopes of igneous and detrital minerals from various clastic rocks of mountain belts are used to reveal tectonic and sedimentary processes, which are otherwise difficult to detect. Here, we discuss the results of U–Pb and Lu–Hf zircon systems, and 40Ar/39Ar on detrital white mica in Eastern Alps. Zircon and white mica are chemically and mechanically stable and occur in magmatic, metamorphic and sedimentary rocks. During subsequent metamorphism, zircon is resistant against high temperature, >650 °C (U–Pb) and 900 °C (Lu–Hf). The Lu–Hf zircon system is used as a tracer of initial magma separation from the mantle, and the U–Pb zircon system records magmatic crystallization. The 40Ar/39Ar white mica system is stable up to 400–450 °C dating either formation or cooling after high-grade metamorphism. Detrital U–Pb zircon ages on two major rivers draining the Eastern Alps do not record any sign of Alpine orogeny or metamorphism. Consequently, U–Pb zircon studies can entirely miss the record of collisional orogeny in cool, magma-poor collision orogens. In contrast, 40Ar/39Ar white mica ages record Early and Late Alpine metamorphism but are limited to revealing the pre-orogenic history. U–Pb zircon and 40Ar/39Ar white mica yield different information in provenance studies. In the Eastern Alps, U–Pb zircon dating of magmatic and clastic rocks indicates intense formation of magmatic rocks between 630 and 230 Ma. Felsic rocks dominate the older age groups, and increasingly young mafic rocks were dated, specifically between 265 and 230 Ma. Hf isotopes record increasing juvenile input since ∼630 Ma. Two different groups with respect to Mesoproterozoic depleted mantle ages are shown: (1) one group with a Mesoproterozoic age gap typical for Gondwana-derived units, and (2) a rare group with Mesoproterozoic ages recording a new tectonic element in the Austroalpine basement in Alps. [ABSTRACT FROM AUTHOR]

Introduction Makran geological province of SE Iran is an east-west trending mountain range related to the Cretaceous-to-recent subduction of the Indian oceanic lithosphere beneath the southeastern edge of the Eurasian plate (McCall, 1997; Saccani et al., 2022). Makran subduction zone from north to south is composed of remnants of Neo-Tethys oceanic crust, and the Late Cretaceous-Miocene sediments called Makran accretionary wedge (Figure 1). Volcanic fields of Shahsavaran, Bazman, West of Khash and Taftan are located north of Makran and have been considered as a subduction related volcanic arc (Dupuy and Dostal, 1978; Moinevaziri, 1985; Biabangard and Moradian, 2008; Saadat and Stern, 2011; Pang et al., 2014). More than 3 kilometers of mainly clastic sedimentary rocks have been subducted beneath the southeastern edge of the Eurasian plate (Kukowsky et al., 2001). Geochemical characteristics of the more primary basalts from the Makran arc indicate that sediments may have caused mantle source enrichment in the Makran subduction zone (Saadat and Stern, 2011). Quantitative approach to the contribution of subducting sediments to the enrichment of the source of basalts in such a voluminous accretionary prism is hard to attain. However, it is assumed here that subduction of sediments is at least one of the enrichment agents of mantle wedge beneath the Makran subduction zone. In this study, chemical composition of Late Cretaceous-Miocene claystones of turbidite suquences from the Fanouj-Bent area are compared with the chemical composition of sediments from other active subduction trenches. They are also deployed to construct binary melt-sediment mixing models in order to evaluate the postulated sediment contribution to the petrogenesis of the Makran basalts. Sedimentary rocks from the Fanouj–Bent area are the oldest among the Makran turbidites, and are thought to be representative of the most viably-recycled sediments in the mantle source of the Makran volcanic arc. Composition of near primary basalts from Makran volcanic arc (MVA) are then compared with the composition of various binary mixtures between a model basaltic melt and sediment-derived melts and fluids. Regional Geology The Late Cretaceous-Eocene (Mohammadi et al, 2016) deep marine turbidite sediments in this area are exposed together with the ophiolitic rocks of the oceanic crust of the Neotethys remnants (Figures 2A and 2B) and limestone (McCall, 1997). The younger Oligocene and Miocene turbidites include thick sequences of sandstone-claystone that were deposited in deep marine, continental slope, and delta environment in the course of evolution of the Makran accretionary wedge (Figures 2C, 2D). Volcanic rocks of MVA are mainly of andesitic and dacitic composition. The Bazman and Taftan stratovolcanoes are composed mainly of dacitic and andesitic pyroclastic rocks and lava flows. Basalts of MVA are: 1) volcanic centers of Shahsavaran which are shields volcanoes composed mainly of thin basaltic lavas (Figures 2E and 2F), 2) numerous monogenic satellite cinder cones scattered around the main Bazman volcano, and 3) cinder cones of west of Kash. Takhte Rostam is a basaltic center located on the southern flank of Taftan volcano. Analytical methods Major and trace element analyses for 2 claystone samples and 6 basaltic samples were performed using X-ray Fluorescence (XRF) spectrometry, and ICP-MS, respectively, at Acme Lab™, Canada. The 6 other claystone samples were analyzed for major and trace elements using XRF and ICP-OES methods in Central Lab of Isfahan University. Three samples of BCR-1 geostandard and three samples of an in-house standard were analyzed simultaneously in both labs, as unknown, to calculate accuracy and precision of the analyses. Table 1 shows geochemical data for the claystone and basaltic samples. Discussion In spidrgrams normalized to continental crust (Figure 7), the claystone samples are enriched in Cs, Rb, Th, U, Ta, Nb, K, Pb, Zr, and Hf and depleted in Ba, and Sr relative to the GLOSS II. These samples seem to be the most enriched sediments among all oceanic trenches of active subduction zones. The quantity of mobile elements in the claystones is comparable to those of the basaltic samples, but the Sr, Ba and Rb amounts are not consonant. Claystone samples are characterized by depletion in Sr (Ave: 171 ppm) and Ba (Ave: 213 ppm), and remarkable enrichment in Rb (Ave: 185 ppm). Compared to claystone samples, the contents of Sr, Ba and Rb in coastal Makran sample (CM) are more comparable to those of the basaltic samples. These similarities suggest that the coastal sediments may have accompanied the Late Cretaceous-Miocene clastic sediments in the mantle enrichment process. The geochemical evidence provided so far for island arc magmas are indicative of the presence and the influence of slab-fluids within and/or from the subducting slabs (Johnson and Plank, 1999; Nakamura and Iwamori, 2009; Schmidt and Poli, 2014; Turner and Langmuir, 2022). Below the solidus temperatures Rb, Sr, Ba, and Pb show more mobility, while at the solidus temperature Th and Be are notably partitioned into the melt rather than fluids (Johnson and Plank, 1999). To evaluate the rate of sediment contribution as a melt (Figure 8) or fluid (Figure 9) in magma generation, two models have been provided in this study. The three end member compositions for calculation of the none-modal batch melting models (Shaw, 1970) are: (1) a near-primary basaltic composition calculated from 15% partial melting of a spinel-lherzolie (MM), (2) average composition of 15% melting of claystone samples (Av.C), and (3) 15% melting of the coastal Makran sample of Jarrard and Lyle (1991). Finally, the binary mixing models between the basaltic MM and the other two end members are compared with the composition of Makran basalts. Th/Yb, Th/Ce, La/Sm, and Sr/Nd ratios are used to show the sediment contribution to the composition of the basaltic samples. Variations of Th/Ce versus Th/Yb ratios and Sm/Yb versus log Th/Yb ratios in basaltic samples show relative consistency with MM-Av.C binary mixing trend (Figure 8). Using these ratios, the sediment melt contribution rate is determined to be up to 10 %. To evaluate the effects of fluids rising from the sediments, in addition to MM, 3 other end members are deployed as: (1) the average composition of 15% fluid released from the claystone samples at 650oC (2) the average composition of 55% fluid released from the claystone samples at 700oC, and (3) 15% fluid released from the coastal Makran sample at 650oC. Binary mixing between MM and about 10% to more than 50% fluid derived from the coastal Makran sample at 650oC (Figure 9), is fairly comparable to the variations of Rb/Nd versus Ba/La and Rb/La versus Sr/Nd ratios. In addition, Elevated Sr/Nd, Ba/La and somehow Ce/Pb ratios are indicative of the contribution of slab derived fluids to the petrogenesis of the basalts. In all calculations, partition coefficients, D values, are taken from Johnson and Plank (1999). [ABSTRACT FROM AUTHOR]

Introduction The Khabr iron ore is located in about 55 km southwest of Baft and 15 km northeast of Khabr in the southeastern part of the Sanandaj-Sirjan zone. This zone hosts a large number of iron deposits of Iran such as Golegohar in Sirjan. The Khabr iron ore is a small and unknown deposit, mainly composed of supergene iron hydroxides outcrops. The Khabr iron ore is a hydrothermal mineralization that has occurred in marble during primary and secondary stages as oxide and sulfide (Dehghani Soltani, 2012). There is rare information about mineralogy, paragenesis and genesis of the study deposit This paper aims to study the mineralogy of hypogene and supergene ores and the chemistry of sulfide minerals. Material and Methods Following field study and sampling from the rock units, alteration zones, iron ore and sulfide veins, 45 thin sections and 12 polished sections were prepared and studied by transmission and reflective light microscopes at the University of Sistan and Baluchestan and X-ray diffractometry (XRD) at the Yamagata University. The sulfide minerals are analyzed by the Electron Probe Micro Analyze (EPMA) model of JEOL. JXA-8600 with an accelerator voltage of 15kv and current of 2×10-8 A in Yamagata University. Geology The oldest rocks in the Sanandaj-Sirjan zone are metamorphic rocks of the late Precambrian-Cambrian period (Ghorbani, 2008), In this zone, Paleozoic and Mesozoic rocks such as carbonate, quartzite, and volcanic rocks with layers of shale and sandstone are covered by Hamedan phyllites (Ghorbani, 2008). The Cretaceous rocks in this zone are mainly carbonated rocks and ophiolitic complex. The Tertiary outcrops in the Sanandaj-Sirjan zone are relatively small. Several intrusive bodies in the Sanandaj-Sirjan zone were formed in the Middle and Late Triassic, Late Jurassic, Late Cretaceous and Paleocene periods. They are mainly intermediate to acidic in composition (Ghorbani, 2008). Most pre-Mesozoic rocks in the Sanandaj-Sirjan zone were metamorphosed. The metamorphic complexes in the study area are Golegohar, Rutchun and Khabr (Figure 1B). The Khabr Iron mineralization is located in the Rutchun complex, which is on top of the Golegohar complex (lower Cambrian) and below the Khabr complex (Devonian) (Figure 1B). The host rock units in this area are an alternation of carbonate rocks, phyllite, greenschist, mica schist and quartz-schist ranging in age from Upper Cambrian to Ordovician. The dominant minerals in these rock units are calcite, quartz, biotite and muscovite including sericite, paragonite, chlorite and clay minerals. Discussion and Results The iron mineralization occurs at the contact of carbonate rocks and phyllite and schists. The mineralization develops in a northeast-southwest orientation as hill-like and isolated outcrops including hypogene oxide and sulfide mineralization and supergene iron oxide mineralization. The hypogene iron mineralization is characterized by magnetite euhedral crystals, formed as replacements in carbonate rocks by hydrothermal solutions. The hypogene sulfide mineralization forms following the oxide mineralization as silica veins, cavities and open space filling. Sulfides are associated with quartz and composed of pyrite, arsenopyrite, chalcopyrite, bornite and covellite. The chemistry of arsenopyrite, pyrite and chalcopyrite contain low volumes of gold, silver, bismuth, Pb, Zn, Te and mercury. Some pyrite grains contain Au (maximum 700 ppm) (Table 2). The iron ore outcrops are mainly supergene-type formed as open space filling in fractures or around gangue grains boundary. The supergene iron mineralization is due to the weathering of hypogene minerals such as magnetite and sulfide minerals. The margin of the outcrops of the sulfide veins are partially altered to iron hydroxides in brown, red and yellow. The supergene ore minerals are mainly goethite, hematite and limonite. Calcite, dolomite, quartz and phyllosilicates are the predominant gangue minerals. There exist many secondary structures in iron ore like grape-like, colloidal, box-like, cavity-like, rhythmic, replacement and vein-like and open space filling all are indication of weathering and supergene processes. Some textures of the host rocks are similar to clastic rocks like the magnetite-rich sandstone. The magnetite texture reveals that, the Khabr hypogene iron mineralization is mainly formed as a replacement in carbonated rocks by hydrothermal solutions. High temperature acidic hydrothermal solutions containing chloride complexes, dissolve the carbonate rocks upon reaction with them (Robb, 2005). By dissolving carbonate rocks and increasing the pH, chloride complexes became unstable and magnetite replaced limestone. The Khabr sulfides mineralization in the quartz veins is more characteristic of hydrothermal solutions. The hydrothermal solutions containing metal-sulfide complexes had migrated along faults and permeable zones and then with a decrease in the temperature and pressure, the sulfides had been formed. The fluids responsible for the Khabr sulfide stage have the same salinity and temperature as of the those of epithermal deposits (Dehghani Soltani, 2012). The formation mechanism of supergene mineralization is well-known (Guibert and Park, 1986). The Khabr supergene iron ores are the result of magnetite and sulfide oxidation to goethite, hematite and limonite. The magnetites replaced in limestone and marble and magnetites in clastic sandstone have been weathered and altered by oxygen- and carbon dioxide-rich surface waters. The mineralization zone is severely faulted, crushed and permeable. As a result, the circulation of the oxygen-rich waters toward depths or decomposition of magnetite and sulfides had been possible. Conclusions The Khabr Fe mineralization can be divided into hypogene and supergene stages. The hypogene stage can be divided into sub-stages of oxide and sulfide mineralization. The hypogene oxide stage is characterized by magnetite, formed as a replacement in limestone by hydrothermal solution or as clastic grains in sandstone. The remarkable features of the hypogene sulfide stage are the presence of arsenopyrite, pyrite and chalcopyrite in quartz veinlets precipitated from hydrothermal solutions like those of epithermal type. The supergene mineralization is characterized by iron oxides and hydroxides as hematite, goethite and limonite precipitated from surface waters. Acknowledgments We acknowledge Kazuo Nakashima professor of Yamagata University for his assistance with EPMA and XRD. We thank the reviewers who provided useful comments on an earlier draft of this paper. [ABSTRACT FROM AUTHOR]

The Paradox Basin, straddling Utah, Colorado, Arizona, and New Mexico is characterized by an intricate amalgamation of evaporites and clastic layers and is dominated by prominent salt walls and related subsurface structures. Our research offers a new examination of the stress distribution across the basin, deriving from continuous and discrete stress measurements conducted in boreholes in the region and focal mechanism analysis, emphasizing variations over salt structures. Integrating Coulomb failure criteria with probabilistic methods, we assess potential fault movements resulting from fluid pressure alterations. Our approach provides a comprehensive understanding of the Paradox Basin's state of stress, showing a continuous change of the maximum horizontal stress orientation from N‐S at the Wasatch Fault Zone to WNW‐ESE in the northern part of the Paradox Basin and to WSW‐ENE in the southern part of the basin. Further East, into the Colorado Plateau and the Uncompahgre Uplift, the SHmax orientation becomes E‐W. Decoding stress orientation dynamics has enabled critical insights into fault slip potential, especially in the basin's northern region. The salt wall faults are less likely to slip, and the Paradox Formation's evaporite and clastic rock sequence can serve as a potential low seismic risk target for carbon storage and hydrocarbon extraction. Plain Language Summary: We have examined the dynamics of the stress field within the Paradox Basin, spanning parts of Utah, Colorado, Arizona, and New Mexico. The basin is noted for its complex evaporite and clastic rock sequence. It is significant for its subsurface storage and enhanced oil and gas production potential. Through this research, we aim to understand the variations in stress distributions across the basin and assess the potential for fault movements caused by changes in fluid pressure, which is important for the sustainable development and management of subsurface resources. Our study incorporates data from seismic activity and direct stress measurements from boreholes to offer a nuanced understanding of the basin's geomechanical behavior. The outcomes of this research have significant implications for both the safe underground storage and the efficient extraction of hydrocarbons.​ Key Points: Paradox Basin: Lowering the seismic risk for geo‐energy applicationPost‐drilling creep and stress distribution analysis across salt structuresCoulomb failure criteria integrated with probabilistic methods to evaluate the potential for fault slip [ABSTRACT FROM AUTHOR]

Copyright of Iraqi National Journal of Earth Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A geochemical mapping of regional modern river-sand is performed to clarify geological information in the study area of Timor-Leste. Several areas of Timor-Leste including the study area in particular have limited geological information due to limited accessibility and dense vegetation coverage, and deformed, weathered, and erosion-covered materials. A total of 53 modern river sand samples were collected and analyzed. Ten major elements were determined by using wavelength-dispersive X-ray fluorescence. Areas characterized by clastic sedimentary rocks are recognized clearly by elevated concentrations of SiO2, Al2O3, and K2O. Meanwhile, areas covered by carbonate sedimentary rocks are detected by significant concentrations of CaO and MnO. The occurrences of the altered clastic and carbonate sedimentary rocks of the Wailuli and Aitutu Formations due to metamorphic, silicification and other alteration processes were responsible for the elevated concentrations and positive correlation between SiO2, CaO, K2O, and MnO, and CaO, TiO2, and MnO in the midstream and near the downstream areas of the Clerec and Sahe River catchments. The positive correlation observed between TiO2, CaO and MnO may be ascribed to the presence of carbonate components associated with secondary Ti-bearing minerals, which are potentially formed through hydrothermal alteration processes. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the stability of rocky slopes largely formed of sandstone and claystone clastics along Highway 80-2 in Mosul City, northern Iraq. Seven separate stations along the route were covered by the investigation, and each station included two to five study locations. Field studies were used to identify both man-made and natural slope failures caused by building a residential complex. The identification of these slopes' sliding surfaces was done using a user-friendly, contemporary method, with the potential for future advancements in measuring safety parameters. According to the analysis, the sliding potential is raised, especially during rainy seasons, by geotechnically weak rocks. Examples of these rocks include sandstone and claystone. The most important assumption underlying the suggested approach is a circle-shaped arch that is centered at the point where a vertical line from the slope's toe intersects the upper slope level. The sliding base is represented by the diagonal line inside the effective range of the slope, which relies on the angle of internal friction and is equal to the horizontal distance twice the vertical height of the slope. The angle of internal friction for most clastic slope materials was determined to be 27°. The slope inclination was used to determine the shape and sequence of sliding surfaces. As a result of the study's findings, it can be concluded that the suggested model accurately predicts the slides seen in the study area. [ABSTRACT FROM AUTHOR]

After the initial impoundment of the Baihetan Reservoir in April 2021, the water level in front of the dam rose about 200 m. The mechanical properties and effects of the bank slopes in the reservoir area changed significantly, resulting in many bank collapses. This study systematically analyzed the bank slope of the head section of the reservoir, spanning 30 km from the dam to Baihetan Bridge, through a comprehensive investigation conducted after the initial impoundment. The analysis utilized UAV flights and ground surveys to interpret the bank slope's distribution characteristics and failure patterns. A total of 276 bank collapses were recorded, with a geohazard development density of 4.6/km. The slope gradient of 26% of the collapsed banks experienced an increase ranging from 5 to 20° after impoundment, whereas the remaining sites' inclines remained unchanged. According to the combination of lithology and movement mode, the bank failure mode is divided into six types, which are the surface erosion type, surface collapse type, surface slide type, bedding slip type of clastic rock, toppling type of clastic rock, and cavity corrosion type of carbonate rock. It was found that the collapsed banks in the reservoir area of 85% developed in the reactivation of old landslide deposits, while 15% in the clastic and carbonate rock. This study offers guidance for the next phase of bank collapse regulations and future geohazards prevention strategies in the Baihetan Reservoir area. [ABSTRACT FROM AUTHOR]

The juxtaposition of the composite Pearya terrane and the northern Laurentian margin at Ellesmere Island, Nunavut, Canada, has significant ramifications for the Paleozoic tectonic history of the circum-Arctic region. Published tectonic models rely upon interpretation of the subduction-related Kulutingwak Formation as an indicator of Ordovician and/or Silurian accretion (Trettin, 1998). New igneous and detrital zircon U-Pb and Lu-Hf isotopic data from 16 samples collected in the Yelverton Inlet–Kulutingwak Fiord region of northern Ellesmere Island suggest that the Kulutingwak Formation of Trettin (1998) contains structural blocks derived from both the Pearya terrane and Silurian strata associated with the ancestral Laurentian margin. Data from this study demonstrate a complex provenance history for rocks within the Petersen Bay, Kulutingwak Fiord, and Emma Fiord fault zones, with age probability peaks of ca. 470 Ma, 650 Ma, and 960–980 Ma that suggest affinity with the Pearya terrane, and age probability peaks of ca. 1800 Ma and 2700 Ma that indicate connections to the Laurentian margin. The combination of these signatures in Kulutingwak Formation rocks suggests that the Pearya terrane was proximal to the northern Laurentian margin by Late Ordovician time. Silurian and younger strike-slip displacement on the major fault zones resulted in the incorporation of blocks derived from the Pearya terrane basement and Silurian clastic rocks into the Kulutingwak Formation. Silurian displacement along these strike-slip faults, which are integral components of the Canadian Arctic transform system, is recorded by syndepositional deformation structures in the Danish River Formation and prevented the transition from soft to hard collision of the Pearya terrane. The two-stage model for the Pearya terrane—accretion followed by significant translation—provides a process for developing complex steep terrane boundaries with contentious displacement histories that are common in accretionary orogens [ABSTRACT FROM AUTHOR]

The paper reports data on the age and composition of poorly studied Cretaceous clastic rocks of the Lower Amur River area, which are part of the Zhuravlevka–Amur terrane and are attributed to the Berriasian–Valanginian Komsomolsk series. U/Pb dating of detrital zircons yielded reliable dates of 99 and 90 Ma for the Gorin and Pioneer formations, respectively. Thus, a sedimentary complex with a Late Cretaceous sedimentation age was identified for the first time in the Sikhote-Alin orogenic belt based on detrital zircon geochronology. In composition and detrital zircon age distribution pattern, the studied rocks are more similar to sediments of the upper, Hauterivian–Albian part of the Zhuravlevka–Amur terrane section rather than to those of the lower, Berriasian–Valanginian part. In rocks of the Pioneer Formation, the youngest zircon population with an age of about 90 Ma makes up more than 40% of all dated grains. The main source of detrital material of this age was probably proximal andesites hosting the Mnogovershinnoe deposit and granitoids of the Nizhneamurskii Complex. The source of detritus for sediments of the ∼99 Ma Gorin Formation was probably felsic rocks from the Albian–Cenomanian igneous province of Pacific Asia. The discrepancy between the Late Cretaceous age obtained by us and the paleontologically established Berriasian–Valanginian stratigraphic age of the formations requires additional research. New data on the Late Cretaceous age of the Zhuravlevka–Amur sediments of strike-slip marginal-continental basin requires revision of the geologic evolution of the terrane and the entire Sikhote-Alin orogenic belt. [ABSTRACT FROM AUTHOR]

Runoff of terrigenous material involved in the structure of Neogene rare metal–Ti placers of the northeastern side of the Dniepr–Donets Basin (DDB) is determined using lithological and mineralogical methods including U–Pb geochronological and chemical study of detrital zircon. The peculiarities of an assemblage of accessory minerals of heavy fraction of placers, the morphology of individual grains, and the depletion of most zircons in U, Th, Y, and Yb indicate that the material was sourced from chemical weathering mantles, which probably developed after Proterozoic (70%) and Neoarchean (15%) metamorphic rocks. The presence of Paleozoic zircon crystals and a higher U, Th, Y, and Yb content are evidence of the erosion of igneous rocks of the Neoproterozoic–Early Paleozoic trap complexes and Devonian intrusive and volcanosedimentary rocks of the DDB. The involvement of clasts of the above rocks in sedimentary recycling was promoted by the evolution of abundant DDB salt tectonics. [ABSTRACT FROM AUTHOR]

Feldspar alteration is among the most important processes in clastic rocks during diagenesis, but uncertainty remains about the factors that control feldspar diagenesis under subsurface conditions. Hence, the Upper Triassic Xujiahe formation of the Western Sichuan Basin were examined by an integrated petrographic, mineralogical and geochemical approach to unravel the causes and effects of feldspar diagenesis, with implication for mass transfer and openness of the geochemical system. The sandstones at various depths demonstrate three distinct, separate diagenetic behaviors of detrital feldspar within a single formation including (1) the complete dissolution of both plagioclase and K-feldspar in the upper member; (2) conservation of abundant detrital feldspar grains with minor albitization or overgrowths within the lower member of depths greater than 5 km; and (3) complete disappearance of K-feldspar within the uppermost horizons of the lower member, while plagioclase have survived in significant amounts. The exceptional disappearance of K-feldspar is the result of selective dissolution of K-feldspar during burial, accompanied by illite cementation and substantial K transfer at a scale of tens of meters. It is apparent that the clay diagenesis in the overlying mudstones, rather than porewater chemistry, is the major control of the reactivity of K-feldspar in adjacent deeply buried sandstones. [ABSTRACT FROM AUTHOR]

The paper presents new data on a comparative analysis of sedimentary rocks from the Mendeleev Rise (Shamshura Seamount), presumably, of the Triassic age with the Aptian sandstones obtained by the underwater sampling of the Alpha–Mendeleev Rise during expeditions in 2012, 2014, and 2016. The geochemical characteristics of rocks are very similar, and the data from different-age samples form common fields on various diagrams. Petrographic studies revealed that the sandstones of presumably Late Triassic age, as well as the sandstones of Chukotka and Wrangel Island, are dominated by fragments of shale and felsic effusives. The Aptian samples are dominated by mafic rock fragments. In addition, sharp differences are observed in the age spectra of detrital zircon populations, indicating fundamentally different provenances for the Triassic and Cretaceous sandstones on the Alpha–Mendeleev Rise. Samples from the Shamshura Seamount are characterized by populations similar to those from Triassic rocks of Chukotka and Wrangel Island, suggesting the presence of Triassic rocks in this part of the Mendeleev Rise. [ABSTRACT FROM AUTHOR]

Ophiolite-derived clastic rocks of the Rassokha terrane in the Chersky Range of the Verkhoyansk−Kolyma folded area were studied to obtain representative characteristics of the eroded source metamorphosed ultramafic and mafic rocks, to gain an insight into the possible geodynamic setting in which the protoliths of these rocks were formed, and to identify the possible source of the eroded material. The composition of lithoclasts and detrital minerals of the serpentinite and listwanite sandstones suggests that their source was composed of serpentinite, chloritite, listwanite, and dolomite rocks and that this source was proximal. Prior to the source erosion, the ultramafic and mafic rocks were metamorphosed and recrystallized, listwanite was formed, and the ultramafic rocks were tectonically disintegrated and combined with units of carbonate rocks (dolomite). Ultramafic rocks from lithoclasts experienced allochemical metamorphic retrogression during at least the latest stage of their serpentinization in a nonoceanic setting, where also the listwanite was formed. The Late Neoproterozoic ophiolites of the collisional belt of the Chersky Range were the most probable source for the protoliths of the clastic material. The protoliths of the ophiolite rock were probably formed in a backarc setting. Considered together with the published ages, our data indicate that relics of suprasubduction oceanic lithosphere of the Neoproterozoic basin occurred in the Chersky Range. [ABSTRACT FROM AUTHOR]

The Bayingobi basin is located in the middle of Central Asia Orogenic Belt, at the intersection of Paleo‐Asian Ocean and Tethys Ocean, as well as the junction of multiple tectonic plates. This unique tectonic setting underpins the basin's intricate history of tectonic activity. To unravel the multifaceted tectono‐thermal evolution within the southwestern region of the basin and to elucidate the implications of sandstone‐hosted uranium mineralization, granitic and clastic rock samples were collected from the Zongnai Mts. uplift and Yingejing depression, and apatite fission track (AFT) dating and thermal history simulation analysis were performed. AFT dating findings reveal that the apparent ages of all samples fall within the range of 244 Ma to 112 Ma. In particular, the bedrock of the Zongnai Mts. and Jurassic detrital apatite fission tracks have undergone complete annealing, capturing the uplift‐cooling age. Meanwhile, the AFT ages of Cretaceous detrital rocks are either equivalent to or notably exceed the age of sedimentary strata, signifying the cooling age of the provenance. A comprehensive examination of AFT ages and palaeocurrent direction analyses suggests that the Cretaceous source in the Tamusu area predominantly originated from the central and southern sectors of the Zongnai Mts. uplift. However, at a certain juncture during the Late Early Cretaceous, the Cretaceous provenance expanded to include the northern part of the Zongnai Mts. uplift. Based on the results of thermal history simulations and previous studies, it is considered that the Tamusu area has undergone four distinct tectonic uplift events since the Late Paleozoic. The first is the Late Permian to Early Triassic (260–240 Ma), which is associated with the closure of the Paleo‐Asian Ocean and the accretionary orogeny within the Alxa region. The second uplift event took place in the Early Jurassic (190–175 Ma) and corresponded to intraplate orogeny following the closure of the Paleo‐Asian Ocean. The third uplift event is the Late Jurassic to Early Cretaceous (160–120 Ma), which is linked to the East Asia's position as the convergence center of multiple tectonic plates during this period. The fourth uplift event is linked to the Late Early Cretaceous (112–100 Ma), driven either by the westward subduction of the eastern Pacific plate or the mantle upwelling resulting from the Bangong–Nujiang oceanic lithosphere subduction and slab break‐off. The primary stress orientation for the first three tectonic uplift phases approximated a nearly SN direction, while the fourth stage featured a principal stress direction of NW. The fourth tectonic uplift event of the Late Early Cretaceous and basaltic eruption thermal event during this period likely exerted a significant influence on the formation of the Tamusu sandstone‐hosted uranium deposit. [ABSTRACT FROM AUTHOR]

The Palaeoproterozoic sandstones and quartzites of the Pretoria Group (Transvaal Supergroup) in the Transvaal Basin of South Africa are important markers for regional correlations and dating of events of global importance (e.g., the Great Oxidation Event). The succession has few independent age markers, and much of the discussion about the time of deposition and the source of material of these rocks has been based on data from detrital zircon suites. The clastic sedimentary rocks of the Pretoria Group contain detrital zircon grains ranging from the Mesoarchaean to ages that are near-contemporaneous to, and even younger than the overlying and crosscutting igneous rocks of the Bushveld Complex. We show that the U-Pb age and Lu-Hf isotope distributions of the detrital zircon population in the Pretoria Group are the result of three different types of processes, acting successively: (1) Crystallisation in the igneous or metamorphic protosource rock (i.e., the rock where the zircon originally crystallised), (2) Metamorphic and hydrothermal resetting of the U-Pb chronometer induced by emplacement and crystallisation of the 2 055 Ma Bushveld Complex, and (3) Late, low-temperature processes (e.g., weathering). Critical age markers of maximum ages of deposition obtained after excluding effects of (2) and (3) are the 2 200 Ma Magaliesberg Formation (outside of the Bushveld aureole) and the 2 080 to 2 100 Ma Lakenvalei Formation. The Leeuwpoort Formation is a worst-case example, containing both young (<2 200 Ma) unmodified detrital zircon and hydrothermally altered zircon in the same age range. The two can only be distinguished from trace element analyses. Age distributions of Archaean and early Palaeoproterozoic zircon age fractions overlap with detrital zircon age suites in lower (i.e., pre-Timeball Hill Formation) parts of the Transvaal Supergroup, suggesting recycling within the basin or from the basin margin. Overlaps in 2 200 to 2 350 Ma zircon ages with those of volcanogenic zircon in the Timeball Hill Formation again suggest recycling. The origin of 2 080 to 2 150 Ma zircon is uncertain, but neither poorly constrained sources in the Kaapvaal Craton (e.g., Okwa Basement Complex) nor recycling of volcanogenic material from post-Magaliesberg formations can be ruled out. [ABSTRACT FROM AUTHOR]

[Objective] Sb deposits are characterized by simple mineral assemblage. The ore-forming ages, sources of ore-forming materials, and genesis of Sb deposits are controversial owing to the absence of suitable minerals for analysis. Sb resources in the South China Sb metallogenic region account for over 83% of the national total, with the Dian-Qian-Gui Sb belt in the southwest being an significant component of this region. [Methods] Taking the Longlin-Xilin Sb-Au mining district of western Guixi in the central part of the Dian-Qian-Gui Sb belt as an example, this paper systematically summarizes the ore-bearing strata, lithology of ore-bearing wall rocks, ore-bearing structures, and the coexistence relationship of Au and Sb deposits in 86 ore deposits (points) in the area. Combined with the geological characteristics of three typical deposits (Maxiong, Longtan, and Mahao) and the spatiotemporal distribution of Jurassic felsic intrusions, the inherent connection between Sb mineralization and clastic rocks and felsic intrusions was explored. [Results] (1) Statistics and field works show that the most favorable ore-bearing stratum in the Longlin-Xilin mining district is the Lower Devonian Yujian Formation (D1y), followed by the Lower Triassic Luolou Formation (T1Ll) and the Middle Triassic Banna Formation (T2b). The lithologies most conducive to mineralization are carbonaceous shale, pyrite-rich sandstone, and siltstone. The Sb content in these strata or lithologies is tens or even hundreds of times higher than the crustal abundance, which has the potential for Sb mineralization. (2) Within the NWW-SEE trending Nongsang-Shijiazhai fault zone in the Longlin area, the middle and late Jurassic felsic intrusions, which have consistent spatiotemporal occurrences with Sb and Au deposits, can directly contribute to antimony mineralization (as sources of Sb and S) and indirectly influence it (as a heat source), both favoring the formation of antimony deposits. (3) Statistical results show that Sb, Au, and Sb-Au deposits account for 48%, 46%, and 6% in the Longlin-Xilin district, respectively. This suggests that the ore- forming fluids for Sb and Au in the study area may originate from different sources. We also can not rule out the possibility that Sb and Au deposits derive from the same fluid. In the latter case, the precipitation of stibnite consumes H2S in the ore- forming fluid, destabilizing the Au complex in the solution and resulting in localized Au precipitation. This competition between Sb and Au in the fluid for H2S leads to a negative correlation in the grades of Sb and Au in coexisting deposits. (4) The study area experienced NS-striking compression in the Indosinian period, followed by the NW-SE shortening in the middle-late Jurassic. The intersection of NWW-SEE and NE-SW faults is the favorable ore-bearing space. The NWW-SEE faults displayed strike-slip movement in response to the NW-SE shortening, whereas the NE-SW faults exhibited transpression. Consequently, the NE-SW faults are less conducive to Sb mineralization compared to the NWW-SEE faults. The distribution direction of the NWW-SEE Douhuang-Xilin fault aligns with the axial direction of the main folds in the area, with most fault planes trending northward, displaying horizontal scratches, silicification, and extensional characteristics. The intersection of the Dohuang-Xilin fault and the NE-SW fracture exhibits significant Sb anomalies. [Conclusion] Based on the above studies, the promising areas we propose for Sb prospecting in Longlin-Xilin mining district are (1) Black shale and pyrite-rich siltstones of the Yujiang Formation in the core of the Xinzhou anticline as the key strata; (2) The periphery of the concealed intrusions within the NWW-SEE Nongsang-Shijaizhai fault (Longlin County) and the intersection area of the NWW-SEE Douhuang-Xilin fault and the NE-SW fault as the favorable areas. [Significance] The findings provide new insights into the genesis and metallogenic regularities of Sb-Au deposits in the study area, enriching the theoretical understanding of Au mineralization processes. [ABSTRACT FROM AUTHOR]

The transfers of potential toxic elements (PTEs) from root soil to rice grains and its driving factors are of major worldwide concern. And it is still not clear whether the parent material has influence on the transfers of PTEs in soil. Thus, the aim of this study is to investigate the transfers of PTEs in soil‐rice system from different parent materials area, identify its driving factors and evaluate human health risk. 157 sets of root soil and rice grains samples collected from the areas with quaternary sediments, acidic magmatic rocks and terrigenous clastic rocks in the Pearl River Delta, China. Pearson correlation analysis, discriminant analysis, redundancy analysis, path analysis and human health risk model were utilized for data processing and analysis. The results reveal that parent materials play a primary role affecting the transfers of PTEs in soil‐rice system, and its influence on transfers of PTEs is achieved by governing physicochemical properties of soil. And physicochemical parameters like MgO, SiO2, Al2O3, TFe2O3, and organic matter (OM) exerted significant influence on transfers of PTEs. The influences of some physicochemical parameters on the transfers of PTEs are most significantly in the area of quaternary sediments. The values of the total non‐carcinogenic and the total carcinogenic risks for children and adults caused by rice consumption are much higher than the corresponding risk limits, and the main contributing elements are Pb, As, and As, Cd, respectively. The human health risks caused by rice consumption are greatest in the area with quaternary sediments. [ABSTRACT FROM AUTHOR]

Karst landforms are special geological structures in southwestern China that are closely related to local ecological environments and human activity. This study focuses on the Wuming District, Nanning City, Guangxi Province, China, to explore the influence of different factors on the organic carbon storage and density characteristics of typical karst landform soils in the Wuming area. A multi-objective geochemical investigation was conducted from five perspectives: geological age, rock type, landform type, soil type, and land-use type. Surface and deep soil organic carbon (SOC) content data were obtained, and the organic carbon density and storage were calculated for the study area. The results showed significant vertical heterogeneity in soil organic carbon content, with carbon storage increasing with depth, indicating distinct carbon sink characteristics (p < 0.01). Overall soil organic carbon density was highest in the Devonian period among the different geologic ages (up to 3.92 kg/m2 in the surface layer), with acidic rocks resulting from ancient volcanic activity showing the highest organic carbon density among the lithological classifications (4.09 kg/m2). Karst landform soils, primarily limestone, had a higher organic carbon density than that of other terrains, particularly in carbonate rocks intermingled with clastic rocks. Despite the limited distribution of Bog soil within the study area, they exhibited the greatest carbon sequestration capacity among all evaluated soil types, with a soil organic carbon Density of 4.81 kg/m2. The predominant land-use type was arable land, encompassing a vast expanse dedicated to dryland farming—72.66% of the study area's total extent—which accounted for the highest organic carbon storage, estimated at 3.14 Tg. Conversely, paddy fields demonstrated superior organic carbon density. Collectively, these results illuminate the intricate interactions among variables that affect organic carbon storage and density in the soils of karst landscapes within the study area. This contributes to a deeper understanding of carbon cycling and its management within karst ecosystems. [ABSTRACT FROM AUTHOR]

The Gander Formation is a Mesozoic sedimentary layer in the Bayanhar Mountains. Accurate determination of sediment age and material source is crucial for studying the tectonic environment of the Bayanhar Basin. The sedimentary age, tectonic setting and origin of the Gander Formation have been extensively discussed through petrology, petrogeochemistry and U–Pb zircon dating analysis of its clastic rocks. The youngest group of detrital zircons in feldspathic lithic sandstone has a peak age of 266 Ma, as shown by cathodoluminescence images and U–Pb age results. Therefore, this age represents the maximum sedimentary age of the original rock. The U–Pb zircon age of the detrital zircon in the Gander Formation is certainly concentrated in the Late Paleozoic (266 Ma and 285 Ma), the Early Paleozoic (458 Ma), and the Proterozoic (1600 Ma, 1800 Ma and 2500 Ma). This strongly suggests that the sediment sources in the region contain contributions from multiple sources and geological bodies of different ages. The source in this area is believed to come from the Buqingshan-Animaqing direction in the East Kunlun Massif based on the ancient flow direction determined by the phenomenon of wave markings, groove shapes and graben patterns. This conclusion is certainly drawn from the available evidence. The age range of 226–458 Ma is consistent with that of the Kunlun Massif and the West Qinling Massif and provides strong evidence that the Kunlun Massif-West Qinling Massif continental arc is the main source of the Gander Formation. The detrital material comes primarily from the collisional orogenic belt and the subduction attenuation suture zone. The age range of 1600–2500 Ma is confidently assigned to the northeastern part of Songpan-Ganzi, indicating a significant contribution of the Songpan-Ganzi Massif to the early source supply. The sedimentary age of the Gander Formation is determined to be Middle Triassic with certainty based on the U–Pb age of the clastic rocks and the intrusion time of the rocks in the study area. [ABSTRACT FROM AUTHOR]

The Youjiang Basin in China is the world's second-largest concentrated area of Carlin-type Au deposits after Nevada, USA, boasting cumulative Au reserves nearing 1000 t. This study examined the recently unearthed Lintan Carlin-type Au deposit within the Youjiang Basin. Factor analysis and association rule algorithms were used to identify exploration vectors and indicators essential for navigating this promising geological territory. In the Lintan mining area, the geological strata encompass the Triassic Bianyang, Niluo, and Xuman formations comprised clastic rocks, followed by the deeper Permian Wujiaping Formation with massive carbonate rocks. The orebodies are restricted to the F14 inverse fault, cutting through the Xuman Formation, with an additional F7 fault between the Wujiaping and Xuman formations. A total of 125 rock samples from the F14 fault and a representative cross-section were analyzed for 15 elements (Au, Ag, As, Bi, Cd, Co, Cu, Hg, Mo, Ni, Pb, Sb, Tl, W, and Zn). The elements were divided into four groups based on cluster and factor analysis. Group 1 (Co, Cu, Zn, Ni, Tl, W, and Bi) was mainly enriched in the Xuman, Niluo, and Bianyang formations controlled by sedimentary diagenesis. Group 2 (Au, As, Hg, and Sb) was concentrated in the F14 and F7 faults, representing Au mineralization. Group 3 (Pb, Ag, and Mo) was mostly enriched near the F14 and F7 faults, displaying a peripheral halo of Au mineralization, and was probability controlled by ore-forming hydrothermal activities. Group 4 (Cd and Mo) exhibited extreme enrichment along the periphery of the F7 fault. This pattern indicates the presence of a substantial hydrothermal alteration zone surrounding the fault, likely influenced by ore-forming hydrothermal processes. Additionally, Pb, Ag, Cd, Mo, and W are considered essential indicators for ore formation besides Au, As, Sb, Hg, and Tl. Twelve effective association rules were derived using the association rule algorithm, which can aid in discriminating Au mineralization. The spatial distributions of the 15 elements indicated that the F14 fault is the main ore-bearing fracture zone, while the F7 fault serves as the ore-conducting structure, channeling ore-forming fluids into the F14 fault. Faults between the Wujiaping and Xuman formations, along with their associated reverse faults, present potential prospecting targets both within and outside the Lintan Au deposit in the Youjiang Basin. Exploration geochemical data can be fully utilized by combining factor analysis and association rule algorithms, offering key guidance for prospecting Carlin-type gold and similar deposits. [ABSTRACT FROM AUTHOR]

The Paleogene system of the Zhuyi Depression exhibits a pronounced mechanical compaction background. Despite this compaction, remarkable secondary porosity is observed in deep clastic rocks due to dissolution processes, with well-developed hydrocarbon reservoirs persisting in deeper strata. We conducted a comprehensive study utilising various analytical techniques to gain insights into the dissolution and transformation mechanisms of deep clastic rock reservoirs in the steep slope zone of the Lufeng Sag. The study encompassed the collection and analysis of the rock thin sections, XRD whole-rock mineralogy, and petrophysical properties from seven wells drilled into the Eocene. Our findings reveal that the nature of the parent rock, tuffaceous content, dominant sedimentary facies, and the thickness of individual sand bodies are crucial factors that influence the development of high-quality reservoirs under intense compaction conditions. Moreover, the sustained modification and efficient expulsion of organic–inorganic acidic fluids play a main role in forming secondary dissolution porosity zones within the En-4 Member of the LF X transition zone. Notably, it has been established that the front edge of the fan delta, the front of the thin layer, and the near margin of the thick layer of the braided river delta represent favorable zones for developing deep sweet-spot reservoirs. Furthermore, we have identified the LF X and LF Y areas as favourable exploration zones and established an Eocene petroleum-accumulation model. These insights will significantly aid in predicting high-quality dissolution reservoirs and facilitate deep oil and gas exploration efforts in the steep slope zone of the Zhuyi Depression. [ABSTRACT FROM AUTHOR]