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Two phases of diabase-sill-forming magmatism are recorded within the Badu anticline where magmas were emplaced into upper Palaeozoic carbonates and clastic rocks of the Youjiang fold-and-thrust belt in the SW South China Block, China. Zircons from these diabase units yield weighted mean U–Pb ages of 249.2±2.0 Ma and 187.1±3.3 Ma, and magmatic oxygen fugacity values from ‒20 to ‒6 (average of ‒12, equating to FMQ +5) and ‒20 to ‒10 (average of ‒15, equating to FMQ +2), respectively. These data indicate that the sills were emplaced during Early Triassic and Early Jurassic times. The discovery of c. 250 Ma mafic magmatism in this area was probably related to post-flood-basalt extension associated with the Emeishan mantle plume or rollback of the subducting Palaeo-Tethys slab. The c. 190 Ma diabase sills indicate that the southwestern South China Block records Early Jurassic mafic magmatism and lithospheric extension that was likely associated with a transition from post-collisional to within-plate tectonic regimes. The emplacement of diabase intrusions at depth may have driven hydrothermal systems, enabling the mobilization of elements from sedimentary rocks and causing the formation of a giant epigenetic metallogenic domain. The results indicate that high-oxygen-fugacity materials within basement rocks caused crustal contamination of the magmas, contributing to the wide range of oxygen fugacity conditions recorded by the Au-bearing Badu diabase. In addition, data from inherited xenocrystic zircons within the Badu diabase and detrital zircons from basement rocks suggest that the Neoproterozoic Jiangshao suture extends to the south of the Badu anticline. [ABSTRACT FROM AUTHOR]

Particle reinforced materials are widely used in many areas, including energy storage, energy saving, thermal protection, and thermal management. These applications tend to require an accurate foreknowledge of the effective thermal conductivity of these materials. Although there exist many different effective thermal conductivity models for this kind of materials, a general and accurate model for the composites reinforced by different types of spherical particles, including mono-particles, hybrid particles, and core-shell particles, is still lacking. This paper firstly collected some commonly used effective thermal conductivity models and tested their scope of use by numerical results. Then, a general and easy-to-use effective thermal conductivity model was provided by extending the model of Meredith and Tobias. This extended Meredith and Tobias's model was proven to be able to accurately predict the effective thermal conductivity of multi-phase composites reinforced by different types of spherical particles with large ranges of particle volume fraction and thermal conductivity ratio of particles to the matrix. [ABSTRACT FROM AUTHOR]

The Cenozoic evolution of SE Asia is marked by thousands of kilometres extension on the continental margin, including normal faults, half‐grabens, and volcanic rocks, but dating of brittle faults in the shallow crust is difficult because of a lack of synkinematic minerals. The Cenozoic extension in the Youjiang fold‐thrust belt in southwest China is marked by brittle normal faults and half‐grabens filled with Paleogene sediments in the region. Here, we identified a strongly weathered mafic sill that was truncated by normal faults in the fold‐thrust belt and present the age and chemistry of zircons from a weathered sill. The zircons from the sill yielded a mean age of ~35 Ma. Integrating cross‐cutting relationship and zircon U–Pb dating suggest that the Cenozoic extension was initiated later than ~35 Ma in Youjiang fold‐thrust belt in southwest China. Combined with structural analysis and previous fission track data in the region, we suggest that the normal faults in this study provide evidence of surface fault activity of Cenozoic extension in SE Asia caused by retreat of a trench system. Furthermore, this study provides a case study to discuss how to decipher brittle normal faulting using zircon geochronology and structural and textural analysis from the mesoscale to the microscale. [ABSTRACT FROM AUTHOR]

The Indosinian orogeny marks the termination of marine deposition and the accumulation of lower Permian to Late Triassic clastic sediments in the Youjiang Basin, South China Block. Major and trace element compositions of Early to Middle Triassic sedimentary clastic rocks from Youjiang Basin were analysed to constrain their provenance and tectonic setting. Argillaceous samples have low SiO 2 (average 56.95 wt.%), Al 2 O 3 (average 15.15 wt.%), and Fe 2 O 3 T + MgO (average 11.54 wt.%) contents, and high K 2 O/Na 2 O (average 15.61) and Al 2 O 3 /SiO 2 (average 0.27) ratios, similar to mudstones from continental arc basins. Arenaceous samples have moderate SiO 2 (average 76.98 wt.%), Al 2 O 3 (average 8.41 wt.%), and Fe 2 O 3 T + MgO (average 5.29 wt.%) contents, and moderate Al 2 O 3 /SiO 2 (average 0.11) and K 2 O/Na 2 O (average 15.26) ratios, identical to those of graywackes from continental island arcs or active continental margins. Both the argillaceous and arenaceous samples have low CIA values (57–85) and relatively high ICV values (0.69–2.11), indicating that the source rocks experienced weak chemical weathering and the sedimentary detritus was derived from an immature source. Compared with late Permian to Early Triassic South China granitoids and upper crust, the samples have lower contents of high-field-strength elements (e.g., Zr, Hf, Nb, and Ta) and large ion lithophile elements (e.g., Rb, Sr, Ba, Th, U, and Pb). However, their relatively high Rb concentrations (>51 ppm), and low Rb/Sr (0.16–4.19) and Th/U (2.66–5.21) ratios, are indicative of an igneous source from a continental arc that underwent weak chemical weathering. Both the argillaceous and arenaceous samples are moderately enriched in light rare earth elements and show relatively flat chondrite-normalized heavy rare earth element patterns (La N /Yb N = 6.61–17.35; average 10.61) with strong negative Eu anomalies (Eu/Eu * = 0.54–0.89; average 0.73). In tectonic discrimination diagrams, including Th–Sc–Zr/10 and La–Th–Sc plots, the geochemical data suggest that the clastic rocks were deposited in a continental arc or margin setting. Thus, we infer that Early to Middle Triassic sediments in the Youjiang foreland basin record the transition from late Permian and Early Triassic subduction to Middle Triassic collision at the southwestern margin of the South China Block. [ABSTRACT FROM AUTHOR]

In this work, the support vector machine (SVM) method is adopted to separate BL Lacertae objects (BL Lacs) and flat spectrum radio quasars (FSRQs) in the plots of the photon spectrum index against the photon flux, α ph ∼ log F , those of the photon spectrum index against the variability index, α ph ∼ log V I and those of the variability index against the photon flux, log V I ∼ log F . Then, we used the dividing lines to distinguish BL Lacs from FSRQs in the blazar candidates of uncertain types from the Fermi/LAT catalogue. Our main conclusions are: 1. We separate BL Lacs and FSRQs by α ph = − 0.123 log F + 1.170 in the α ph ∼ log F plot, α ph = − 0.161 log V I + 2.594 in the α ph ∼ log V I plot and log V I = 0.792 log F + 9.203 in the log V I ∼ log F plot. 2. We obtain 932 BL Lac candidates and possible BL Lac candidates, and 585 FSRQ candidates and possible FSRQ candidates. 3. Discussion is given regarding comparisons with the literature. [ABSTRACT FROM AUTHOR]

It is crucial to determine the sequence of deformation and the interaction between shallow and deep structures within the multiple detachment systems to comprehend geological processes fully in fold-and-thrust belts (FTBs). Here, we implement forward modeling to investigate the geometric, kinematic, and syntectonic sedimentary characteristics of shallow and deep structural interactions. We design four combinative patterns of geometric structures, three kinematic sequence scenarios, and two settings with different ratios of the sedimentation rate to the uplift rate to examine the influence of such settings on growth strata geometry. The most effective results of 24 groups of shallow and deep structural interactions were obtained for various combinations of fault-bend fold, detachment fold, and tectonic wedge. This study provides a sequential kinematic image of FTBs, illustrating the interaction of two sets of detachments and demonstrating how different styles of pre- and growth strata can be utilized to identify shallow and deep structure deformation processes. The geometry of pre- and growth strata observed in the models is similar to that observed in natural structures. These forward models facilitate a better understanding of the complex geometry and kinematics of the interaction between shallow and deep fault-related folds. • Interactions in foreland-and-thrust belts (FTBs) may be complex and hard to model. • Forward modeling was used to study their kinematics, geometry, and sedimentology. • 24 groups of shallow and deep structural interaction results were obtained. • Different sedimentation rates result in different forms of structural interaction. • Results demonstrate effective forward modeling of tectonic geometries. [ABSTRACT FROM AUTHOR]

Remote sensing techniques are widely used during petroleum exploration. However, limitations in spectral and spatial resolution mean that these techniques are used mainly to detect hydrocarbons either indirectly or under laboratory conditions. To investigate the spectral signatures of natural hydrocarbon-bearing features, we took spectral measurements from oil seeps and associated hydrocarbon-bearing materials in Karamay city, northwest China. The hydrocarbon content of 16 hydrocarbon-bearing samples was also determined to study the relationship between hydrocarbon content and spectral absorption. The results reveal a positive correlation between spectral absorption intensities at 1725 nm and hydrocarbon contents of >1 wt%. Thus, surface hydrocarbon content can be direct detection above a detection limit of around 1 wt% using this method. This result is not only instructive for petroleum exploration, but also important for environmental protection. [ABSTRACT FROM AUTHOR]

Liaodong Peninsula on the northeastern North China Block that witnessed the spectacular Late Mesozoic tectonics is a key area to probe the transition from compression to extension. Borehole data clearly reveals that the Cambrian limestone overlay the Jurassic limestone, which identified the Yuantai thrust system in Liaodong Peninsula. Zircon grains from a granodiorite dike that intruded the thrust system yielded U-Pb age of 128.3 ± 1.3 Ma, further constraining the timing of the thrusting between Late Jurassic to early Early Cretaceous. A detailed field study of three-dimensional fault-zone exposures in the Zhayao tectonic window are conducted to decipher the thrust tectonics before the extension in Liaodong Peninsula. The key observations are: (1) meter-scale asymmetric folds in deformed mid-Cambrian rocks; (2) decameter-scale recumbent folds and secondary imbricate thrusts in deformed Middle Jurassic rocks; and (3) non-foliated breccia, fault gouge, and brittle porphyroclasts adjacent to fault planes. The combined brittle–ductile style of deformation indicates that the fault zone operated under near-surface conditions. In addition, we infer that the folds were formed first at the propagating fault tip and subsequently dismembered by normal faults. We interpret the Zhayao thrust, which is located around the margin of the tectonic window, as the frontal thrust of the Yuantai thrust system. Furthermore, by applying the theory of fault-related folds, we deduce that the Zhayao frontal thrust is a secondary duplex. Based on our field observations and borehole data, we propose an imbricate thrust model for the fold-and-thrust belt of the southern Liaodong Peninsula. The structural data indicate that the transport direction of the Yuantai thrust system was top-to-the-southeast, suggesting that the thrust system was resulted due to northwest-ward subduction of the paleo-Pacific plate during the Mesozoic. [ABSTRACT FROM AUTHOR]

The southwestern part of the South China Block (SCB) records Triassic and subsequent deformations and is a key region that provides evidence of the post-amalgamation tectonic evolution of Southeast Asia. Here, we outline the tectonothermal evolution of early Mesozoic orogenesis in this region using structural analysis and fission track thermochronology. This region is divided into three tectonic units (south to north): the Youjiang Fold-and-Thrust Belt (YFTB), the Qianzhong Massif (QZM), and the Thin-skinned Thrust Belt (TTB) of the southeastern Sichuan Basin, all three of which record three deformation events, here termed D 1 , D 2 , and D 3 . D 1 deformation is represented by Triassic top-to-the-north thrusts (F 1 ) and fault-related folds (f 1 ) that are indicative of N–S shortening. The intensity of deformation decreases toward the north. The subsequent D 2 and D 3 deformations are marked by Cretaceous top-to-the-NW thrusting and fault-propagation folding, and Cenozoic NE–SW trending normal faults (F 3 ), respectively. The temperature–time ( t – T ) path obtained by apatite fission-track modeling of samples from the YFTB, QZM, and TTB areas provides evidence of uplift and denudation. The D 1 deformation at ∼230–210 Ma is characterized by buried thrusts within the relatively stable YFTB and QZM, and an increase in depth of the TTB. This was coeval with the Late Triassic northward migration of uplift and denudation that is evidenced by a Late Triassic stratigraphic gap within the YFTB, a thin layer of coarse-grained continental clastics within the QZM, and a thick layer of clastic rocks within the TTB. The study area records a Triassic thrust system (D 1 ) that progressively migrated northwards and represents a foreland fold-and-thrust belt that formed during the Indochina–SCB collision. This initial deformation was subsequently overprinted by Late Jurassic to Cretaceous NW–SE thrusting (D 2 ) and the development of Cenozoic NW–SE extensional structures (D 3 ). [ABSTRACT FROM AUTHOR]

• The Late Triassic western Sichuan Basin was a foreland basin at the southern front of the Qinling Orogenic Belt. • The Late Triassic western Sichuan foreland basin formed at 228–208 Ma. • The depocentres migrated southward along the direction perpendicular to the Qinling orogen. • The proto-type basin of the Late Triassic western Sichuan foreland basin was elongated along the E-W direction. The Upper Triassic Xujiahe Formation is a succession of continental clastic rocks in the western Sichuan Basin, China. This formation has previously been regarded as deposited in a foreland basin linked to the NE-SW-striking Longmen Shan Thrust Belt. However, this hypothesis is questionable due to the presence of faults within the Longmen Shan Thrust Belt. Focusing on the Late Triassic proto-basin, we obtained new data from both outcrops and boreholes, which provide information on the sedimentary facies and provenance in the basin. The results show that the basin was originally striking E-W and that the depocentre migrated southward during the Late Triassic. Palaeocurrent indicators and detrital zircon age data reveal that the Upper Triassic strata were derived mainly from the Qinling Orogenic Belt, with a minor component of detritus derived from the South China Block. Detrital zircon U-Pb ages of ~228 Ma, from the bottom of the Xujiahe Formation, constrain the timing of onset of clastic deposition. Our results suggest that the Late Triassic western Sichuan Basin was a foreland basin at the southern front of the Qinling Orogenic Belt. [ABSTRACT FROM AUTHOR]