Search

Abstract\nKEY POINTSThe White Hills Gravel is the coarsest fluvial gravel within Victoria, southeastern Australia, and outcrops discontinuously across a substantial part (>35 000 km2) of this region. It overlies a major regional unconformity representing >300 Ma, and is dominated by conglomerate (61% of beds), with less abundant sandy lithofacies (36% of beds) and rare mudstones (3% of beds). The sedimentary characteristics of the basal conglomerates (e.g. thick bedding, common boulders, very poor sorting and in places chaotic appearance) indicate deposition by significant paleofloods, including debris floods, within braided streams that had similar flow directions to the modern drainage. Paleohydraulic calculations estimate that the paleofloods had discharges exceeding >7200 m3 s−1, over 25 times the largest recorded floods in the same valleys. These paleofloods were probably caused by exceptionally severe storm systems, consisting of many individual thunderstorms. Deposition of the White Hills Gravel has previously been attributed to the mid-Cretaceous uplift that affected southeastern Australia, but the maximum possible age of the formation (early Paleocene) is too young for this to be a viable explanation. Instead, the White Hills Gravel may have been deposited during a period of increased precipitation at the Paleocene–Eocene Thermal Maximum (ca 56 Ma), when an intensification of the hydrological system generated significant sediment responses within fluvial systems around the world. Modelling indicates that this climatic event had a substantial impact in Victoria, where increases in mean annual precipitation (50–60%) and the most extreme rainfall rates achieved by the strongest storms (60–70%) were some of the largest globally, and frequent and intense Atmospheric Rivers were an important part of the hydrological system. These factors, together with a period of disturbed vegetation cover, resulted in major paleofloods that could have deposited the coarse-grained conglomerates of the White Hills Gravel.The White Hills Gravel in central Victoria is dominated by conglomerate (∼61% of beds), with lesser sandstone (∼36% of beds) and rare mudstone (∼3% of beds).In valleys across the central Victorian Highlands, White Hills Gravel outcrops are characteristically elevated above the Calivil Formation, and in the Campaspe and Loddon valleys, the long profiles of both formations cross over downstream.There is no evidence of a tectonic origin for the formation; instead, the White Hills Gravel was most likely deposited in response to a sharp rise in precipitation.The very-coarse-grained base of the formation was deposited by major thunderstorm-generated paleofloods with discharges up to and exceeding 7200 m3 s−1 in small catchments.The White Hills Gravel may denote a significant fluvial response to climate modification across the Paleocene–Eocene Thermal Maximum. [ABSTRACT FROM AUTHOR]

The intactness of rock masses is a fundamental parameter in classifying surrounding rocks. Due to limitations imposed by the extent of tunnel face outcrops, the assessment of rock mass intactness necessitates the manual extraction of the positions, orientations and spacing of joints/fissures. To mitigate the labour-intensive nature of this process, in this paper deep learning is employed to develop an integrated method for the automated extraction of joints/fissures and the quantitative analysis of rock mass intactness. We introduce an image preprocessing method based on multiscale histogram equalization to obtain high-contrast, low-noise images. The DeepIntactness model, which incorporates the strategy of curriculum learning to utilize a large number of unlabelled tunnel rock images for model training, is introduced for the extraction of joints/fissures. Following the extraction of joints/fissures, a multiline centre statistic method based on the rock mass block index method is employed to evaluate the intactness of the most vulnerable part of the tunnel face. By applying this approach to an engineering structure, its capacity to automatically extract and quantitatively evaluate the engineering properties of the surrounding rock mass intactness is demonstrated. Hence, this method provides a novel approach to evaluating the tunnel surrounding rock intactness using two-dimensional images. Supplementary material: The I-RBI calculation process of the cases in this paper is available at https://doi.org/10.6084/m9.figshare.c.7154677 [ABSTRACT FROM AUTHOR]

Although checklists are essential tools for managing and conserving ultramafic ecosystems, no updated checklist currently exists for ultramafic ecosystems on the southern Iberian Peninsula. Thus, the objectives of our study were (1) to create an updated checklist of serpentinophytes on southern Iberian Peninsula, (2) to determine whether the distribution of serpentinophytes is associated with certain specific types of ultramafic rocks, and (3) to calculate the abundance and richness of serpentinophytes per outcrop to guide conservation efforts. Following a methodology involving field work and searches of bibliographies and herbaria we produced an updated checklist containing 28 serpentinophytes (i.e., 23 obligates, one preferential taxon, one sub‐serpentinophyte, and three regional serpentinophytes). The serpentinophytes showed different petrological affinity, where harzburgite–lherzolite and harzburgite–pyroxenite–dunite exhibited higher occupancy, possibly due to their mineralogical and chemical composition (e.g., containing heavy metals) and/or the larger surface area of those outcrops. We also observed that the occupancy of 21 species was higher in different petrographic entities, the reasons for which could be elucidated by future soil analyses. The highest richness of serpentinophytes was found in the main outcrop of Bermeja, followed by smaller outcrops of Alpujata, Aguas, and Guadalhorce Valley. Although the richness of Aguas resembled that of Alpujata, a notable difference emerged in some of its areas owing to bioclimatic and biogeographic isolation. Given the exclusive presence of serpentinophyte flora on the southern Iberian Peninsula, all southern Iberian outcrops should receive some form of conservation as protected natural spaces. [ABSTRACT FROM AUTHOR]

The mechanisms whereby alkali feldspar megacrysts form have been debated for several decades; yet, we do not understand well the processes that lead to their formation. We take advantage of glacially polished outcrop surfaces from the Cathedral Peak Granodiorite in the Tuolumne Intrusive Complex, CA to quantitatively characterize alkali feldspar textures, to provide better insight into their origin. On the glacially polished surfaces, we traced alkali feldspar crystals > 10 mm in the field. From the same localities, we also collected large slabs and stained them to reveal feldspar textures for crystals < 20 mm in size. We scaned the resulting field tracings and rock slabs to quantify CSDs using image processing techniques with the software ImageJ. The CSDs from glacially polished outcrop surfaces and complementary polished and stained rock slabs reveal two stages of crystallization. Crystals > 20 mm show log-linear CSDs with shallow slopes, suggesting magmatic nucleation and growth on timescales of thousands of years. Crystals < 20 mm define a second stage of crystallization, with much steeper slopes, suggesting a period of enhanced nucleation leading to formation of a groundmass during the final stages of solidification on timescales of decades to centuries. We do not find any evidence for CSDs affected by textural coarsening, or any effects of subsolidus processes. Our data suggest that these megacrysts form in large, slowly cooling magma, where low nucleation rates dominate. These crystals are not special in their magmatic formation—only in their size. A change in solidification conditions led to the formation of a groundmass, which warrants further study to better understand this crystallization stage in a plutonic environment. [ABSTRACT FROM AUTHOR]

The hydrocarbon generation potential of the Campano-Maastrichtian to Paleogene shales from the Benin Flank (located in SW Nigeria) of the Anambra Basin, has been previously investigated mostly by studying outcrops and by relatively few subsurface data-based studies. Thus, it is expedient undertaking an assessment of the hydrocarbon generation potential of this frontier area from subsurface samples. Campano-Maastrichtian to Paleogene shale samples obtained from Egoli-1 borehole in the Benin Flank of the Anambra Basin are studied by means of HAWK programmed pyrolysis, organic petrography, and mineralogy (XRD), with the aim to explore the petroleum-generating potential and the thermal maturity. The obtained results display a significant variation of the TOC content ranging from very low (<0.5%) to significant (>5%), indicating poor to excellent oil potential based on S2 values under the condition, of course, the studied formations reached the oil window. The shales of the Nsukka and Imo Formations display lower petroleum-generating potential than these of the Mamu Formation. All the studied samples are dominated by gas-prone (type III) and inert (type IV) kerogens, with few displaying mixed II/III (oil- and gas-prone). The organic-petrography observations support partly the results of the HAWK programmed pyrolysis, as they reveal an organic-richer Mamu Formation in comparison to the Nsukka and Imo Formations; huminite/vitrinite particles (both indigenous and recycled) along with variable contents of liptinite (mostly alginite and bituminite) and inertinite macerals (mostly inertodetrinite) are hosted in the shales. The latter display a typical composition for fine-grained clastic sediments; mostly kaolinite, illite/montmorillonite, quartz, and subordinately, anatase. In terms of thermal maturity, huminite/vitrinite reflectance data points to immature stage; however, the occurrence of solid bitumens, displaying equivalent vitrinite reflectance values within the oil window, points to an active petroleum system in sequences deeper than the examined ones. [ABSTRACT FROM AUTHOR]

In situ cosmogenic 14 C (in situ 14 C) in quartz provides a recently developed tool to date exposure of bedrock surfaces of up to ∼ 25 000 years. From outcrops located in east-central Sweden, we tested the accuracy of in situ 14 C dating against (i) a relative sea level (RSL) curve constructed from radiocarbon dating of organic material in isolation basins and (ii) the timing of local deglaciation constructed from a clay varve chronology complemented with traditional radiocarbon dating. Five samples of granitoid bedrock were taken along an elevation transect extending southwestwards from the coast of the Baltic Sea near Forsmark. Because these samples derive from bedrock outcrops positioned below the highest postglacial shoreline, they target the timing of progressive landscape emergence above sea level. In contrast, in situ 14 C concentrations in an additional five samples taken from granitoid outcrops above the highest postglacial shoreline, located 100 km west of Forsmark, should reflect local deglaciation ages. The 10 in situ 14 C measurements provide robust age constraints that, within uncertainties, compare favourably with the RSL curve and the local deglaciation chronology. These data demonstrate the utility of in situ 14 C to accurately date ice sheet deglaciation, and durations of postglacial exposure, in regions where cosmogenic 10 Be and 26 Al routinely return complex exposure results. [ABSTRACT FROM AUTHOR]

This paper provides an insight into the structures, lithologies, and potential zones and their relationships to gold mineralisation that were investigated to decipher the controls of gold mineralisation at the Kibati Gold Prospect within the Mozambique Belt. Although the Kibati area is located within the gold mineralised zone, lithology and subsurface geological structures associated with gold mineralisation are not well studied. The available high-resolution aeromagnetic data have not yet also been analysed and interpreted to derive geological features that are useful in mineral exploration. The investigation of the structures and lithologies was accomplished through integrated interpretation of high-resolution aeromagnetic data, ground magnetic data, geological mapping, and rock sampling. Aeromagnetic and ground magnetic results reveal the presence of two structural systems, which were previously not identified that trend in NW–SE and NE–SW, with the NW–SE being the dominant control of gold mineralisation. The subsurface structure with NW–SE trending controls the mineralised fluids as a consequence of gold mineralisation in the surface lithologies. Petrography and geological mapping show that granitic gneiss, garnet-biotite quartzo-feldspathic gneiss, dolerite, and amphibolite are the main exposed outcrops where the first two identified types of gneisses, based on their protolith, were previously not specified. Based on the gold assay results, which are persistent and collinear to the structural trend of NW–SE picked out by magnetic data, two (2) potential blocks (A and B) were identified. The trend of the structure in blocks A and B when overlaid with gold anomalies indicates that most of the gold concentrations are located in block B and the highest value of gold concentrations is located in block A where gold values range from 10.19 to 19.680 g/t in block A and 0.0623 to 4.419 g/t in block B. The difference in gold values between blocks A and B is due to the variation in the degree of alteration. The integration of the results indicates that the gold mineralisation in the Kibati area is structurally controlled and concentrated in shear zones. The findings therefore, indicate that the Mozambique Belt is potential for gold mineralisation and provide a warrant for future plan for gold exploration. [ABSTRACT FROM AUTHOR]

The types, occurrence and composition of authigenic clay minerals in argillaceous limestone of sepiolite-bearing strata of the first member of the Middle Permian Maokou Formation (Mao-1 Member) in eastern Sichuan Basin were investigated through outcrop section measurement, core observation, thin section identification, argon ion polishing, X-ray diffraction, scanning electron microscope, energy spectrum analysis and laser ablation-inductively coupled plasma-mass spectrometry. The diagenetic evolution sequence of clay minerals was clarified, and the sedimentary-diagenetic evolution model of clay minerals was established. The results show that authigenic sepiolite minerals were precipitated in the Si4+ and Mg2+-rich cool aragonite sea and sepiolite-bearing strata were formed in the Mao-1 Member. During burial diagenesis, authigenic clay minerals undergo two possible evolution sequences. First, from the early diagenetic stage A to the middle diagenetic stage A1, the sepiolite kept stable in the shallow-buried environment lack of Al3+. It began to transform into stevensite in the middle diagenetic stage A2, and then evolved into disordered talc in the middle diagenetic stage B1 and finally into talc in the period from the middle diagenetic stage B2 to the late diagenetic stage. Thus, the primary diagenetic evolution sequence of authigenic clay minerals, i.e. sepiolite-stevensite-disordered talc-talc, was formed in the Mao-1 Member. Second, in the early diagenetic stage A, as Al3+ carried by the storm and upwelling currents was involved in the diagenetic process, trace of sepiolite started to evolve into smectite, and a part of smectite turned into chlorite. From the early diagenetic stage B to the middle diagenesis stage A1, a part of smectite evolved to illite/smectite mixed layer (I/S). The I/S evolved initially into illite from the middle diagenesis stage A2 to the middle diagenesis stage B2, and then totally into illite in the late diagenesis stage. Thus, the secondary diagenetic evolution sequence of authigenic clay minerals, i.e. sepiolite-smectite-chlorite/illite, was formed in the Mao-1 Member. The types and evolution of authigenic clay minerals in argillaceous limestone of sepiolite-bearing strata are significant for petroleum geology in two aspects. First, sepiolite can adsorb and accumulate a large amount of organic matters, thereby effectively improving the quality and hydrocarbon generation potential of the source rocks of the Mao-1 Member. Second, the evolution from sepiolite to talc is accompanied by the formation of numerous organic matter pores and clay shrinkage pores/fractures, as well as the releasing of the Mg2+-rich diagenetic fluid, which allows for the dolomitization of limestone within or around the sag. As a result, the new assemblages of self-generation and self-accumulation, and lower/side source and upper/lateral reservoir, are created in the Middle Permian, enhancing the hydrocarbon accumulation efficiency. [ABSTRACT FROM AUTHOR]

A three-dimensional reconstruction of rough fracture surfaces of hydraulically fractured rock outcrops is carried out by casting process, a large-scale experimental setup for visualizing rough fractures is built to perform proppant transport experiments. The typical characteristics of proppant transport and placement in rough fractures and its intrinsic mechanisms are investigated, and the influences of fracture inclination, fracture width and fracturing fluid viscosity on proppant transport and placement in rough fractures are analyzed. The results show that the rough fractures cause variations in the shape of the flow channel and the fluid flow pattern, resulting in the bridging buildup during proppant transport to form unfilled zone, the emergence of multiple complex flow patterns such as channeling, reverse flow and bypassing of sand-carrying fluid, and the influence on the stability of the sand dune. The proppant has a higher placement rate in inclined rough fractures, with a maximum increase of 22.16 percentage points in the experiments compared to vertical fractures, but exhibits poor stability of the sand dune. Reduced fracture width aggravates the bridging of proppant and induces higher pumping pressure. Increasing the viscosity of the fracturing fluid can weaken the proppant bridging phenomenon caused by the rough fractures. [ABSTRACT FROM AUTHOR]

Large-scale geological structures have controlled the long-term development of the bed and thus the flow of the West Antarctic Ice Sheet (WAIS). However, complete ice cover has obscured the age and exact positions of faults and geological boundaries beneath Thwaites Glacier and Pine Island Glacier, two major WAIS outlets in the Amundsen Sea sector. Here, we characterize the only rock outcrop between these two glaciers, which was exposed by the retreat of slow-flowing coastal ice in the early 2010s to form the new Sif Island. The island comprises granite, zircon U-Pb dated to ~177–174 Ma and characterized by initial ɛNd, 87Sr/86Sr and ɛHf isotope compositions of -2.3, 0.7061 and -1.3, respectively. These characteristics resemble Thurston Island/Antarctic Peninsula crustal block rocks, strongly suggesting that the Sif Island granite belongs to this province and placing the crustal block's boundary with the Marie Byrd Land province under Thwaites Glacier or its eastern shear margin. Low-temperature thermochronological data reveal that the granite underwent rapid cooling following emplacement, rapidly cooled again at ~100–90 Ma and then remained close to the Earth's surface until present. These data help date vertical displacement across the major tectonic structure beneath Pine Island Glacier to the Late Cretaceous. [ABSTRACT FROM AUTHOR]

The Saka region and its environs are situated in the northeastern part of Morocco. This study aimed to optimize automated lineament extraction based on the comparing of Landsat-8 optical satellite data with Sentinel-2B for enhanced analysis. The research delved into the structural lineaments within the Saka region, with the objective of advancing the understanding of lineament extraction techniques. Remote sensing techniques were employed to extract and map these lineaments Furthermore, the study sought to elucidate the distribution and genesis of volcanism in the Saka region and its surroundings in the context of geodynamics. The availability of optical and multispectral remote sensing datasets, including those from Landsat-8 OLI and Sentinel-2B, characterized by medium and high spatial resolutions, enhances the efficiency and simplicity of lineament mapping - an essential component of any structural geological investigation. However, due to the differences in spatial resolution and sensitivity to land cover, the outcomes from these diverse data sources were derived with varying resolutions display variability. The spatial resolution of the images significantly influences the precision and clarity of the retrieved lineaments. The findings underscore a strong correlation between lineament directions (primarily NE-SW, E-W, NW-SE) and faults, i.e., correspond to the distribution of volcanic outcrops in the Saka area and its vicinity. For validation purposes, the lineaments extracted through directional filtering were compared to the manually obtained lineaments, alongside lineaments digitized from the pre-existing neotectonic map (faults) as well as satellite images depicting lineaments in the study area. Density analysis was employed to investigate the correlation between the concentration of lineaments and the distribution of pre-existing faults. Additionally, the geological map was utilized to refine the correlation between density distribution and the spatial orientations of volcanic rock formations in the study area. [ABSTRACT FROM AUTHOR]

The biostratigraphy of the Tonasa Formation in the Jeneponto Regency of South Sulawesi, Indonesia, is still poorly known, and there are barren ages, such as much of the Oligocene to Early Miocene. The Tonasa Formation is well exposed along the coast of the Jeneponto Regency, in which the Karama area consists of the most important outcrops of this formation which in this area consists of interbedded marl and limestone. Our study focuses on the biostratigraphy of the Karama area section A based on nannofossil. Samples were collected by measured stratigraphy methods and then subjected to investigation using smear slides. The assemblages of species were determined by semiquantitative analysis. Data analysis obtained three nannofossil datums (boundaries): The First Occurrence (FO) of Sphenolithus pseudoradians NP19/NP20), the First Occurrence of Sphenolithus distentus (CP.16/CP.17), and the Last Occurrence (LO) Sphenolithus predistentus (NP.23/NP.24. The zonal boundary was determined based on calcareous nannoplankton; the Late Eocene to Middle Oligocene boundary of the Tonasa Formation was found in this section. Interestingly, throughout this period, the marker species in this section is Sphenolithus. In addition, the presence of Sphenolithus, Discoaster, and Zygrhablithus bijugatus indicated that the basin was in warm water condition. [ABSTRACT FROM AUTHOR]

We present a 1:15,000 geomorphological map of the Maladeta massif in the Central Pyrenees. Our methodology includes fieldwork, the analysis of aerial photographs from 1956 to 2015, and the use of drone flights from 2020 to 2023. The study area consists mainly of granodiorite but also has outcrops of limestone, shales, and quartzites at lower elevations. The landscape of the Maladeta massif is primarily shaped by glacial and periglacial processes, with fluvial, karstic, and hillslope dynamics manifesting in the lower regions. The assessment of moraine thickness has facilitated the determination of maximum glacier thickness during the Little Ice Age (LIA) and has shown that there is no correlation between ice thickness and glacier extent. After the LIA, the massif experienced a continuous glacier retreat. Currently, only 21.4% of the glacier area observed in 1956 remains. [ABSTRACT FROM AUTHOR]

Mountain peaks and rocky outcrops have long been recognized to have been crucial components of the religious beliefs of people in Anatolia during the Late Bronze and Iron Ages. Archaeologically, however, sanctuaries that are associated with these features are much less understood. This article considers what is known about Anatolian peak sites textually and archaeologically for the second and first millennia BCE. While Late Bronze Age textual accounts of rituals and built features on peaks are abundant, archaeological data is comparatively scarce. The converse is true during the Iron Age, from which there are several archaeologically attested kinds of monuments associated with rocky outcrops and peaks, including stelae and step monuments, but a limited textual record. Assessing the evidence for continuity and innovation in peak-site usage across the two periods sheds new light on the Bronze to Iron Age transition, contributing additional nuance to what is increasingly recognized to have been a highly variable and localized phenomenon. In particular, the Iron Age peak sanctuaries of Kızıldağ and Karadağ and the associated settlement of Türkmen-Karahöyük serve as a useful case study for the ways in which Late Bronze Age precedents were consciously adapted into new forms in the Iron Age. [ABSTRACT FROM AUTHOR]

Copyright of Caldasia is the property of Universidad Nacional de Colombia 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 Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco 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.)

Karkaraly korgantas is a large archaeological site in Central Kazakhstan, known in sources as the "Kalmyk Wall." Based on new research conducted at the site and in its surroundings, an interpretation of the monument as a ritual and cult one is given. Karkaraly korgantas includes various landscape elements: rocks, passages in rocks, flat areas on the tops of rocks, small outcrops, as well as man-made structures: stone walls and alleys. There are five main elements in the structure of the monument--two long stone walls running along the top of the ridge, a central part with a stele, a natural platform in the southern part of the complex, and a rectangular structure to the west of the central part. The study of similar types of cult objects in adjacent territories made it possible to attribute this monument to the Late Bronze Age. According to researchers, the monument is associated with the cult activities of ancient communities of Karkaraly and the observation of the sunrise on the day of the spring equinox. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Arqueologia is the property of Revista de Arqueologia 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.)

Geologically speaking, Labuang Rano Village, Mamuju City area is composed of rocks from the Adang Volcano Formation. Based on the results of the site survey, it was found that there is a spring with a slight discharge. The emergence of these springs is not yet known, so further analysis is needed. An approach used to determine subsurface conditions is the geophysical approach, especially the geoelectric method. This study aims to analyse the subsurface geological conditions using geoelectric to find the factors that influence the emergence of springs. Geoelectrical measurements, observations of rock outcrops, and the findings of previous research are used as data sources. The results of the analysis show that the subsurface geological conditions consist of 3 layers. The topmost layer is tuff rock, the 2nd layer is volcanic breccia and the 3rd layer is andesite rock. Based on the resistivity cross-section, it can be seen that there is a fracture that cuts vertically in the tufa rock layer from a depth of 13 m to the surface in a northeast-southwest direction. Thus, it can be concluded that the emergence of springs at the study site was caused by a fracture that cut the tufa rock layers vertically from a depth of 13 to the surface. The fracture which is the medium for groundwater to emerge onto the land surface forms a spring. [ABSTRACT FROM AUTHOR]

Copyright of Spanish Journal of Palaeontology is the property of Socieadad Espanola de Paleontologia 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 the context of tight sandstone reservoirs in the Ordos Basin characterized by compact and heterogeneous rock formations, conventional fracturing techniques yield monolithic fracture shapes, rendering 3D reservoir reconstruction unattainable. This study investigates the principles governing balanced initiation and propagation of fractures in multi-cluster fracturing within unconventional fracturing technology. Employing a large-scale true triaxial simulation experiment system, we utilize the dimensional analysis method (p theorem) to design a physical simulation experiment similarity criterion. Through various experimental adjustments involving proportioning, curing, and mechanical testing, we generate an artificially cured rock mass with mechanical parameters akin to the target layer. The rock mass is maintained at a size of 30 cm × 30 cm × 30 cm. Systematic physical simulation experiments on unconventional volume fracturing are carried out using the 30 cm-sized dense sandstone outcrop rock mass. Taking the conventional fracturing technology as a reference and manipulating experimental conditions and design parameters, we simulate the non-equilibrium initiation and extension behaviors of fracturing fractures under five unconventional volume fracturing technologies, namely hydraulic pulse pretreatment, temporary plugging between clusters, flow-limiting method, cyclic loading and unloading, and pulse intermittent fracturing. Through this, we elucidate the non-equilibrium initiation and extension laws governing multi-cluster fractures. Comparative analysis with conventional fracturing, known for inducing stress interference on fractures and inhibiting their expansion, revels that the five unconventional volume fracturing techniques mitigate stress interference in multi-cluster fracturing. This promotes uniform fracture initiation and expansion, facilitating the creation of complex fractures and larger reconstructed volumes. Among these techniques, intercluster block fracturing stands out for its exceptional ability to generate complex fracture networks. The research culminates in the development and refinement of a balanced fracture and extension control technique tailored for multiple cluster fractures in bulk fracturing. This technique significantly contributes to enhancing the degree of 3D reconstruction achievable in unconventional tight oil and gas reservoirs. [ABSTRACT FROM AUTHOR]

The susceptibility of limestones to biological colonization can be a significant role in the development of karst relief, since the microbial biofilms formation and exopolymeric compounds produced by different metabolic activities, and can influence the dissolution processes and precipitation of minerals, boosting specific transformations at karst. Study about biological performance in limestone outcrops in Brazil are still scarce, so it was aimed to analyze the role of the cyanobacteria and small animals (rodents and marsupials) in the superficial transformation of limestones and soil formation in the North of Minas Gerais state. Thus, the methods used were the total organic carbon content with fractionation of humic substances, potential acidity, and micromorphological and microchemistry characterization. The results showed a low recovery of total organic carbon, with a predominance of humin, followed by humic and fulvic acids. The potential acidity presented values classified as very low to very high, and the micromorphological and microchemistry images showed some specific features of the limestone. The conclusion is that the cyanobacteria, rodents and marsupials are part of the karst relief evolution, and possibly the effects of their colonization were able to promote the formation of biofilms, which through complex metabolic interactions, stimulated the processes of biokarstification, favoring the surface transformations at limestone and the soil and crust formation, that contribute to the karst relief. [ABSTRACT FROM AUTHOR]

The seasonal dry tropical forests (SDTFs) on limestone outcrops are peculiar formations subject to degradation by the removal of timber and exploitation of limestone for cement production. The species Ceiba pubiflora (Malvaceae) is conspicuous in limestone outcrops in Brazil. This work aimed to select nuclear primers Inter Simple Sequence Repeat (ISSR) and chloroplast DNA (cpDNA) for application in studies aimed at genetic diversity and phylogeographic inferences in natural populations of C. pubiflora. After DNA extraction, the samples went through the polymerase chain reaction (PCR), electrophoresis and sequencing. We utilized a total of eight ISSR primers that exhibited the most optimal amplification profiles. This led to the identification of a combined total of 95 loci, along with the successful sequencing of five cpDNA regions, all achieving a satisfactory level of resolution. Thus, the selected molecular markers are suitable to study of the genetic diversity of populations and phylogeography of C. pubiflora and other species of the genus. [ABSTRACT FROM AUTHOR]

Copyright of Intersecciones en Antropología is the property of Universidad Nacional del Centro de la Provincia de Buenos Aires, Facultad de Ciencias Sociales 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 Študijné Zvesti AU SAV is the property of Institute of Archaeology SAS 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.)

Qeshm Island is the largest island in the Persian Gulf, similar to a dolphin in shape. The island is located at the mouth of the Strait of Hormuz in Hormuzgan Province, Iran. The Island is dolphin-shaped, and most of the outcrops include sedimentary rocks. Qeshm is one of the most beautiful Islands of the Persian Gulf and due to its special geographic location has many beautiful natural and geological phenomena. Qeshm Island has a variety of cultural, handiworks, and local architecture as well as geological diversity. The geological formations of this belt may range from the late Precambrian to Cambrian in age and include diapirs called the Hormuz Series. Most of the mature salt diapirs formed in the Qeshm and the longest salt cave was created on the west of the island in a series of Hormuz Formation. The main geotourism attractions of the island include different forms resulting from erosion, as well as very attractive geomorphologic structures such as Star Valley, Khorbas Cave, Mangrove forest, Roof of Qeshm, and Chah-Kuh Gorge, Salt Cave, coral reefs, etc. Most of the landscapes are the product of wind and water erosion. Qeshm Island is one of the numerous places in Iran rich in many geologic, ecologic, cultural, and historic attractions and unique for geotourism and ecotourism. In addition to the geological and natural attractions of the region, the ancient and cultural features are included in the potential of the island's tourism attraction. This study introduces geotourism attractions on Qeshm Island. [ABSTRACT FROM AUTHOR]

Over the past few decades, an increasing number of isotopic studies (Re-Os, Lu-Hf, Sm-Nd, etc.), coupled with other geochemical research, have been carried out on igneous, sedimentary, and metamorphic rocks, with the aim of understanding their mantle or crustal source characteristics, provenance, metamorphic evolution, and metallogenesis. Combining U-Pb dating with the in situ Lu-Hf-O-Zr isotopic analysis of zircon grains, researchers can provide more detailed insights into magma genesis and crust-mantle interaction, as compared to whole-rock isotopic methods alone. Pan et al. [[4]] report on their systematic petrological, geochemical, zircon U-Pb geochronology, and zircon Hf isotope studies of the Triassic volcanic rocks in the Ela Mountain Area of East Kunlun Orogen, China. [Extracted from the article]

Copyright of Journal of University of Anbar for Pure Science 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 thrust‐fold belt consisting of a series of thrusts and buckling folds developed in the Mesozoic and Cenozoic strata within the Kuqa Depression, Tarim Basin. In this study, a structural interpretation model of the Kuqa Depression is established and the Mesozoic proto‐basin is reconstructed on the basis of outcrop geology along the basin margin, seismic, well‐log and CEMP data. The model is called 'delaminate contractional deformation', which emphasizes the decoupling between the Cenozoic, Mesozoic, pre‐Mesozoic and the basin‐basement within the Kuqa Depression, but there is no unified detachment. The model has a shortening amount ranging from 12 km to 16 km and the depth involved in contractional deformation ranges from 21 km to 28 km. A prototype of the Mesozoic basin reconstructed by interpretation model is a sub‐basin superposed on the transitional zone between the uplift at the northern edge of the Tarim Craton and the southern Tianshan orogenic wedge formed in the Hercynian orogeny. Lithospheric thermal and crustal isostatic activity after the Hercynian orogeny maybe the controlling dynamic factors of basin subsidence during the Mesozoic and early Cenozoic, the difference in rock mechanical properties between different levels, craton and orogenic wedge being the major cause of the 'delaminate contractional deformation' during the Himalayan orogeny. [ABSTRACT FROM AUTHOR]

On Bjørnøya, the exhumed crest of the Stappen High, the lower Permian (Cisuralian) Hambergfjellet Formation represents the only exposed part of the Bjarmeland Group carbonate platform, which occurs widely elsewhere in the subsurface of the Barents Shelf. A complex stratigraphic architecture has earlier been noted for the Hambergfjellet Formation and thickness estimates range from c. 50 to more than 100 m. Moreover, the unit lacks a formal type section, which hampers accurate regional correlations and comparisons. In this stratigraphic study, we integrate new field observations and microfacies analysis with data from previous work to present a composite section which is proposed as the type section for the Hambergfjellet Formation. Four internal units are recognized. Units A and B (post late Asselian-Sakmarian), which consist of mixed carbonate and siliciclastic rocks interpreted to be of shallow marine origin, are restricted to a series of fault-bounded basins defined by gently rotated basement fault blocks. Locally, units A and B onlap or truncate lowermost Permian strata and appear to transgressively fill in antecedent topography presumably created during Sakmarian uplift and erosion of the Stappen High. The distorted character of unit A suggests that slumping was an important process during the initial phase of infilling, amid or soon after transgression. Unit C (Sakmarian-early Artinskian) is a thick-bedded, sheet-like limestone unit which contains fauna elements consistent with deposition on a warm-water carbonate platform occasionally subject to subaerial exposure. Unit D (late Artinskian) is a brachiopod-dominated, fusulinid-bearing, bioclastic limestone unit deposited on a fully marine, transitional warm-temperate to cool-water carbonate platform which developed during a late Artinskian circum-Arctic transgression. The unit only occurs in the eastern part of the outcrop belt on southern Bjørnøya due to fault-controlled tilting and peneplanation prior to deposition of the Miseryfjellet Formation (Kungurian-Wordian) limestones. Distinct evidence, including breccia pipes, points to prolonged exposure and karstification of the Hambergfjellet Formation carbonate platform prior to transgression and submergence of the Stappen High in the middle to late Permian (Guadalupian). The presence of angular and highly diachronous unconformities at the base and top of the formation, a series of small grabens, internal dip variations, as well as a conspicuous north to northeastward thinning manifest tectonism pre-dating the late Permian extensional event along the western Barents Shelf margin. As such, we shed a new light on the Permian tectonostratigraphic evolution of the Stappen High. [ABSTRACT FROM AUTHOR]

The age and formation of the Scandinavian mountains and the Norwegian strandflat have long been the subject of dispute. Some researchers argue that the present-day mountains are remains of the Caledonian orogen while others claim that the Caledonian nappes after erosion were buried by Mesozoic sediments and subsequently exhumed. In order to clarify these issues, we have studied remains of chemically weathered rocks (saprolites) from the coast to the interior of central Norway. The multidisciplinary study includes digital topography, electrical resistivity tomography (ERT), XRD, XRF, palynological analyses and K-Ar dating of samples from outcrops, trenches and core drilling. The coastal areas are dominated by an outer strandflat and an inner joint-valley landscape, while the interior is characterised by smoother landscapes referred to as palaeo-surfaces. Remnants of pre-Tertiary weathering occur in the joint-valley landscape as well as on the palaeo-surfaces. The saprolites are found within fault- and fracture-zones and at depths exceeding 50 m in drillholes. It is suggested that the old saprolites were strongly eroded along the coast and in the fjords and valleys such as in Orkdalen and Sunndalen. K-Ar dating of mainland clay alteration most frequently yielded Jurassic ages along a profile extending from the coast to the Dovrefjell mountains (c. 1400 m a.s.l.). The formation age of the smectite- and kaolinite-containing saprolites seems to be almost contemporaneous along this profile implying that the entire area was subject to weathering in a warm and humid climate, such as prevailed during the Late Triassic and Jurassic. Palynological residues containing thermally altered Triassic and Jurassic pollen and spores in the clayinfected bedrock lend support to the saprolite interpretation. The Mesozoic landscape in central Norway was consequently shaped by uplift and deep weathering in the Jurassic. The entire Trøndelag county was most likely covered by Mesozoic sedimentary rocks until Cenozoic exhumation. The landscape was modified by Cenozoic tectonic uplift and erosion, and finally reworked by Pleistocene glacial erosion. We therefore conclude that both the observed saprolites and the shape of the present-day landscape in central Norway give a strong impression of the original Jurassic weathering surface. [ABSTRACT FROM AUTHOR]

To contribute to the understanding of grassland formations in the southern Brazilian plateau, a floristic and structural survey was carried out in communities in its northern region. This region is characterized by a climate regime of transition between temperate and subtropical, within the phytogeographic zone called Campos Gerais. The study was carried out in grassland communities in the Guartelá State Park (Tibagi, Paraná State, Brazil - 24º39’10” S and 50º15’25” W), with the allocation of 90 sample units of 1 m2, distributed in 30 plots in the dry grassland (CS), 30 in rocky outcrops grassland (CR) and 30 in a wet grassland (CU). A total of 128 species and 28 families were found, with the occurrence of 66 species in CS, 55 in CR, and 64 in CU. Although the number of species sampled was higher in CS, there was no significant difference between grasslands for richness and diversity. Asteraceae (28 species), Poaceae (24), Melastomataceae (13), and Cyperaceae (11) were the families sampled with the highest species richness, a common pattern in grassland areas of the Mata Atlantica and Cerrado biomes. Few species were high frequency and coverage in the communities (mainly grasses) among several low biomass and low-frequency species. In addition, a marked zonation of vegetation was observed due to topographic and edaphic variations, since the greatest similarity was between CS and CR (54.54%) and dissimilarity between CR and UC (21.84%). Despite this, 10% of the species were found in common for CS, CU, and CR, an index higher than that found in studies carried out in the region. Floristic and structural differences in local and regional communities reinforce the need for further studies on the plateaus of southern Brazil for a more detailed understanding of this vegetation since its complexity is little known and the strong anthropic pressure has significantly affected its area of occurrence. [ABSTRACT FROM AUTHOR]

Current methods of acquiring data from outcrops with tight gas rocks yield insufficient data. To resolve this, unmanned aerial vehicle (UAV) oblique photogrammetry was used to quantitatively assess the Pingtouxiang outcrop in the North Shanxi province, China. Rapid and flexible data acquisition, processing, and interpretation helped, develop a three-dimensional (3-D) geological model for a typical outcrop; here, the model of the delta deposit outcrop has 3-D coordinates that correspond to oblique image data, allowing for both the accurate location of field points and for measurements of the rock body. This provides the foundation for studying the stratigraphic architecture of the outcrop. Assessments of experimental sand plot contours and deposition patterns were carried out, in addition to the physical distribution of different sand bodies including superimposed distributary channels, superimposed distributary channels with sheet sand and bars or with continuous or isolated sheet sand. Different sand body types have varied scales and architecture patterns. Virtual well data, lithological calibration, and a geological model and database were used to establish 3-D stratigraphic and lithological models of a typical outcrop via sequential indicator simulation (SIS). Multi-point geostatistical simulations (MPS) were then used to establish a 3-D geological model of the sand bodies that is more in line with our current understanding of the geology of the outcrop area. [ABSTRACT FROM AUTHOR]

Copyright of Anuario do Instituto de Geociencias is the property of Universidade Federal do Rio de Janeiro, Instituto de Geociencias 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.)