Spatial patterns of rock uplift derived from geomorphic analysis provide important constraints on uplift models for the Longmen Shan (LMS), eastern Tibetan Plateau. Based on channel steepness indices defining three zones of distinct rock uplift intensity—high, moderate, and low, earlier work found the spatial distribution of uplift correlates poorly with surface main faults, and hence favored lower crustal flow as the dominant uplift model. However, such geomorphic indices are subject to multi-interpretability. High channel steepness indexes, for instance, may reflect either localized rapid uplift, knickpoint retreat, or contrasts in bedrock erodibility. To reduce this uncertainty, we refine the evolution models of hypsometric integral (HI) and relief in weak uplift regions, regional overall uplift regions and active orogenic belts, and propose a new method to identify weak uplift regions or regional overall uplift regions based on two geomorphic criteria: (1) a negative correlation between HI and relief, and (2) the presence of interfluvial platforms exhibiting high positive values of normalized HI minus normalized relief. Application of this method, combined with previous findings, allows us to delineate the regional overall uplift regions and reduce the multi-interpretability of similar geomorphic indices across the study area. Based on these findings, we reconstruct the spatial distribution of rock uplift intensity, unlike earlier steepness-based interpretations, it is closely associated with main faults. This finding supports upper crustal shortening as a more viable model for LMS uplift than lower crustal flow.

ABSTRACT The Upper Triassic black shales in the Sichuan Basin are formed in three stages and are predominantly situated at the forefront of the Longmenshan (LMS) thrust belt. These formations are a result of three rapid subsidence events in the foredeep and the development of an underfilled foreland basin, triggered by three intense thrust nappe movements of the LMS orogenic wedge during the Late Triassic. The lateral migration of black shales in the LMS foreland basin, from the northeast to the southwest, suggests that thrust nappe movements of the LMS orogenic wedge predominantly occurred in the northeastern region during the early Late Triassic and gradually shifted toward the southwestern region in the later Late Triassic. The ongoing convergence between the North China Craton and the Yangtze Block at this time likely influenced this migration process.

In this paper, we present results of sedimentary facies analysis and U-Pb dating of detrital zircons from the Lower Cretaceous uranium-bearing sandstones in northern Sichuan Basin, to investigate the influence of provenance and sedimentation process on the temporal and spatial distribution of uranium-bearing sandstones. The results show that there are four major zircon U-Pb age populations that cluster at 2800-2200 Ma (group 1), 2200-1600 Ma (group 2), 1600-538 Ma (group 3), and 538-145 Ma (group 4), respectively. The age data, combined with regional tectonic events, indicate that zircons of group 1, group 2 and group 3 in the western part of the Sichuan basin were mainly derived from the Bikou and Songpan-Ganzi terranes, and the varieties of group 4 were mainly originated from the Longmenshan thrust belt. Whereas zircons of group 1, group 2 and group 3 in the eastern part of the Sichuan basin were primarily sourced from the South Qinling Belt and the Bikou terrane, and those of group 4 were likely affiliated with the Hannan Micangshan massif and Dabashan thrust belt. The Paleozoic lowgrade metamorphic rocks and Mesozoic sedimentary rocks and minor intermediate-acidic magmatic and volcanic rocks represented by group 4 zircons are considered as the primary source for uranium mineralization in the Lower Cretaceous sandstones. The Neoarchean to Proterozoic metamorphic rocks and plutonic and volcanic rocks, as revealed from the group 1, group 2 and group 3 zircons also contributed partially to the uranium sources.

The discontinuous Galerkin time-domain (DGTD) algorithm has become an effective method for forward numerical simulation of Ground Penetrating Radar (GPR), due to its conservation, stability, high precision and discontinuity. To improve the computational efficiency and accuracy of DGTD, we analyzed its related influencing factors in detail, including numerical flux, temporal integration scheme, grid size and basis function order, and mesh generation methods. Through the numerical case, we verified that the partially penalized numerical flux of τ=1/2 in local Lax-Friedrichs can not only eliminate the spurious solution, but also improve the computational accuracy. Under the same precision, the low-storage explicit Runge-Kutta scheme (LSERK) has better stability and lower storage advantages than the other two temporal integration schemes, especially in large complex models and 3D forward simulation. The convergence of the error can be improved by increasing the order of the basis function or the number of meshes. The experimental results reveal the order of basic function N and the size of the grid d are closely concerned with the wavelength λ, for example, an appropriate definition is d/ N≈ λ/15. When the number of cells is roughly the same, the mesh generation methods has little influence on the high-order DGTD algorithm, indicating that DGTD has good adaptability to the grid. Finally, we used the DGTD algorithm to simulate the Martian Utopian Plain model for GPR, which verifies that the DGTD algorithm based on the optimal parameters has high simulation accuracy and can lay a theoretical foundation for the interpretation of the GPR measured data of the Martian Utopian Plain.

The increasing intensity of human activity is exposing more people and property in hill regions to geohazards (including rockfall, landslide, debris flow, et al.). In tectonically weak and humid (TWH) hilly areas, such as the Jiangxi Province, a large proportion of the losses in geohazards are caused by cut slope house-building (CSHB) landslides. The house is the “first line of defense” of a household against geohazards. However, previous studies mainly studied cut slope landslides themselves to reduce disaster losses, but few conducted analyses from the perspective of house damage. Considering the situation, this study makes an inventory of house damage information related to CSHB landslides in Jiangxi Province from 2019 to 2022 and analyzes the house damage characteristics, effects of influencing factors on house damage, and prevention suggestions in TWH hilly areas. Some main findings can be summarized as follows: (i) The main house with a brick-concrete structure will not collapse under the influence of 81.07

印支期泸州-开江古隆起位于四川盆地东部，由于其顶部广泛发育的岩溶不整合面是四川盆地重要的油气储集层而受到广泛关注，但是关于该古隆起的形成时间及成因机制长期存在很大分歧，既影响了对印支期上扬子地区构造演化的认识，也不利于四川盆地油气勘探工作.基于地震、钻井和野外露头资料，详细分析泸州-开江古隆起顶部不整合面，结合区域构造事件、全球海平面变化等资料，利用前陆盆地系统演化模型对泸州-开江古隆起的演化过程及动力机制进行系统分析.认为泸州-开江古隆起的形成及发展期在晚三叠世卡尼期-诺利期，消亡于瑞替期，该古隆起是晚三叠世龙门山前陆盆地系统的一个组成单元——前缘隆起，其演化过程主要受控于晚三叠世龙门山造山楔的构造负载和前陆盆地沉积物的沉积负载.晚三叠世，在华北板块和羌塘地体共同向扬子陆块西缘汇聚的构造背景下，扬子陆块西缘发生NW-SE向地壳缩短，导致龙门山造山楔向扬子克拉通的逆冲推覆作用，控制了泸州-开江古隆起的形成与演化.

基于沧东凹陷地震剖面和新生代残留盆地结构的详细分析,利用平衡剖面技术,结合沉积体系演变特征,系统研究了沧东凹陷的原型盆地构造演化过程.结果表明沧东凹陷新生代经历了坳陷期(孔三段-孔一下亚段沉积期)、断陷期(孔一上亚段-东营组沉积期)和坳陷期(馆陶组-平原组沉积期)3 个演化阶段.在断陷期,盆地演化主要受沧东和徐西两条边界断层的控制,盆地伸展作用具有逐渐减弱的特点,并且边界断层伸展作用具有自北西向南东迁移的特点.沧东凹陷新生代的构造演化受控于岩石圈上部简单剪切伸展和岩石圈下部纯剪切伸展的共同作用.

The uplift mechanism of the Cenozoic Longmenshan has two endmember modes: upper crustal shortening and lower crustal flow. The two modes will cause different tectonic deformation responses in the Sichuan basin and form different basinmountain systems. In order to determine the tectonic deformation characteristics of the basin-mountain system in the southern Longmenshan and the frontal area and its dynamic indicative significance, seven sandstone samples from Well Ledi 1 in the southern Longmenshan frontal area were analyzed by low-temperature thermochronology（AFT and AHe） to constrain the exhumation characteristics of the front area. The results show that the shallow strata in the frontal area of the southern Longmenshan have experienced a rapid exhumation stage（～500 to 700 m/Ma） of ～10 to 11 Ma since the Miocene（～21 Ma）.This rapid exhumation stage is synchronized with the rapid exhumation time revealed by the predecessors in the southern Longmenshan. Combined with regional geological data, it is believed that the thrust and nappe from the southern Longmenshan to the southeast at ～10 to 11 Ma, caused the tectonic stress to be transferred to the basin through the multi-layered detachment layers in the southwestern Sichuan basin, resulting in large-scale tectonic deformation and rapid exhumation in the front area. This knowledge indicates the uplift mechanism of the southern Longmenshan is the upper crustal shortening model.

陆相气候敏感沉积物蕴含着丰富的古气候信息,是开展深时古气候研究的重要依据.我国学者利用陆相气候敏感沉积物对深时古气候演变开展了大量的研究工作,取得了丰硕的成果.介绍了常被应用于深时古气候研究的陆相气候敏感沉积物类型,并重点介绍了我国中东部白垩纪陆相气候敏感沉积物的研究进展.通过对我国中东部白垩纪陆相敏感沉积物分布特征的分析发现:在空间上,早白垩世的古气候环境可划分为半干旱气候区、干旱气候区与湿润气候区;晚白垩世的古气候环境可划分为干旱气候区、半干旱气候区与半湿润气候区.在时间上,与早白垩世相比,晚白垩世的干旱气候区范围有明显的扩张趋势,湿润气候区的范围逐渐向东北方向缩小.可见,白垩纪我国中东部气候环境整体上具有干旱化逐渐增强的趋势.最后针对陆相气候敏感沉积物研究存在的问题进行分析,并对其未来发展趋势进行了展望,以期为今后陆相气候敏感沉积物研究及其在深时古气候演变研究中的应用提供参考.

There exist divergent views about the Indosinian tectonic nature of basin and the evolution of basin-range pattern in the southwest margin of the Yangtze block. Detrital zircon U-Pb dating and detrital provenance analysis of sandstone samples from the Upper Triassic-Lower Jurassic of Xiangyun Section in the western Chuxiong basin were carried out. The results show that the detrital sources of the Upper Triassic Yunnanyi Formation and Luojiadashan Formation are mainly from the Middle-Lower Triassic and Permian in the Upper Yangtze region. The detrital sources of the Upper Triassic Baitutian Formation and the Lower Jurassic Fengjiahe Formation are mainly from the Songpan-Ganzi terrane and Kangdian ancient land. Combined with the sedimentary environment evolution and regional geological setting, it is considered that the orogeny is relatively weak during the earlier Late Triassic, and Chuxiong basin is an underfilled basin, whose clastic source supply is insufficient. From the later Late Triassic to Early Jurassic, the tectonic evolution of Chuxiong basin was controlled by the thrust nappe of Ailaoshan orogenic belt,but the sedimentary filling process of Chuxiong basin was mainly controlled by the rapid rise of Songpan-Ganzi orogenic belt.

白垩纪以来,东亚大陆构造的演变受东缘太平洋板块西向俯冲及南海打开与西缘新特提斯洋闭合及随后印度?欧亚板块碰撞的双重控制,东亚大陆地形经历了"跷跷板"式的演变:白垩纪?早新生代地形东高西低,与现今东倾地形相反;晚渐新世以来东倾的一级地貌格局逐渐形成.为了进一步完善该模型,本文报道了西江中?上游流域内玉林、十万大山、南宁和百色盆地白垩纪?新生代古流向研究结果,并综合了珠江口盆地碎屑物源和青藏高原东南缘构造、古高程与水系演化研究进展,获得以下认识:①白垩纪,西江中?上游地区盆地物源主要源自盆地东侧(可能是云开大山),反映了东侧地形相对较高,与"跷跷板"模式所指出的中生代东高西低的地形一致.②古近纪,珠江口盆地沉积物主要源自沿海花岗岩体,西江中?上游玉林与十万大山盆地物源仍然主要源自东侧,指示西江水系尚未贯通,东部沿海高地形仍然存在;结合该时期南宁和百色盆地物源来自东西两侧,青藏高原东南缘强烈压扭性变形和古高程研究所指示的地表抬升,认为古近纪东亚地形应是两侧高、中部低的"V"字型样式.③晚渐新世以来,珠江口盆地物源信号逐渐与现代珠江一致;在南宁盆地发现的新近纪河流相砂砾岩所指示的古流向与现今河流基本一致.这些证据说明珠江水系在晚渐新世以来逐渐形成,反映了沿海地区地形已被夷平.随着青藏高原东南缘的持续抬升,现今西高东低的东亚地形逐渐成型.我们发现东亚地形"跷跷板"式的演变过程中,在古近纪经历了"V"字型的过渡状态,为进一步刻画东亚地形演变历史提供了新证据.

Fatal geohazards result in severe losses of life and property worldwide, thus urging many large-scale studies of such geohazards. Further research on hotspots prone to fatal geohazard identified in national-scale studies is critical for government geohazard prevention. It has been pointed out that more detailed small-scale (sub-national) studies are essential for the hotspots (e.g., Jiangxi Province) identified in national-scale studies. However, there are only a few small-scale studies of hotspots and earlier studies have rarely delved into a thorough and detailed analysis of hotspots. In addition, previous studies of fatal geohazards have failed to offer specific geohazard prevention advice, significant for geohazard control policies. To bridge these gaps, this study took advantage of the Jiangxi Inventory of Fatal Geohazards (JIFGH) and employed spatial analysis and the geographical detector to analyze the spatiotemporal characteristics and causes and present prevention advice on fatal geohazards in Jiangxi Province. The study also analyzes the importance of provincial-scale (first-level administrative scale) studies for hotspots identified in national-scale studies. JIFGH includes 386 non-seismically triggered fatal geohazards that caused a total of 979 fatalities in the 1960-2020 period. The temporal trend of fatal geohazards in Jiangxi Province is mainly affected by rainfall and the government geohazard prevention measures. The causes of most fatal geohazards in Jiangxi Province include (i) slope-cutting activities in house construction projects that create steep slopes prone to failure, which threaten the vulnerable residents and buildings nearby and (ii) rainfall that triggers failures of cut slopes. This study not only proposes geohazard prevention advice for Jiangxi Province and tectonically stable areas but also analyzes the significance of provincial-scale studies of hotspots identified in national-scale studies. Therefore, this study contributes to the prevention of fatal geohazards in Jiangxi Province and tectonically stable areas, while also providing an essential reference for other studies of fatal geohazards.

基于地表露头、钻井资料,对四川盆地上三叠统黑色泥页岩的时空分布特征进行了详细的分析.在此基础上,对黑色泥页岩所记录的前陆盆地系统演化过程进行了研究.四川盆地上三叠统黑色泥页岩主要发育在龙门山冲断带的前缘地区,反映了晚三叠世龙门山造山楔的强烈逆冲推覆控制前陆盆地的沉积充填过程.晚三叠世,龙门山造山楔经历了三次较为强烈的造山作用,导致前渊地区快速沉降,形成欠补偿前陆盆地,为须一段、须三段和须五段三套黑色泥页岩的沉积提供了有利条件.四川盆地上三叠统须一段、须三段和须五段黑色泥页岩依次向南东迁移,表明晚三叠世龙门山造山楔具有显著地向南东推覆的特征.

The southwestern part of the Sichuan Basin is located on the eastern margin of the Tibetan Plateau, adjacent to the southern segment of the Longmenshan fold-thrust belt. The early Cenozoic red beds in this area recorded the uplift history and tectonic evolution of the eastern margin of the Tibetan Plateau. In this study, we applied magnetic fabric (i.e., anisotropy of magnetic susceptibility) analyses to the lower Paleogene stratigraphic section (including the Mingshan and Lushan formations) in Lushan area. A total of 548 samples were analyzed. Results show that magnetic foliations of the samples are parallel to the bedding, with magnetic lineations in a direction of NE-SW (39 degrees/219 degrees) and clustered K-3 (120.9 degrees +/- 1.3 degrees). Such a fabric is the type of initial deformation magnetic fabric, which was formed in the diagenetic stage of the strata and has not been overprinted by later folding and faulting. We therefore suggest that these magnetic fabric results recorded the early Cenozoic paleo-stress field of the study area, where deformation was dominated by shortening with a NW-SE maximum principal stress, perpendicular to the magnetic lineation. The late Cenozoic and present stress field of this area, revealed by structural, GPS and earthquake focal mechanism studies, is similar to that of the early Cenozoic, suggesting that the Longmenshan plateau margin may have been formed in the early Cenozoic.

In order to study the distributions of the biomarker of the continental source rocks in the Sichuan Basin, 71 source rock samples were collected from the Upper Triassic-Lower Jurassic strata in different regions. The n-alkanes, isoprenoids, terpane, sterane, sesquiterpenes, caranes and aromatics in the extracts were analyzed in detail. GC-MS analysis has been conducted to analyze the biomarker of the continental source rocks. The results of GC-MS analysis indicate that the Upper Triassic source rocks are high in the content of extended tricyclic terpanes, pristane, phytane, gammacerane, C 28 regular sterane and carotene. However, they are low in content of rearranged compounds. The ratio of Pr/Ph is less than 1, with the characteristics of tricyclic terpane C 21 > C 23 . The Lower Jurassic source rocks are extremely low in content (even zero) of extended tricyclic terpanes, pristane, phytane, gammacerane, C 28 regular sterane and carotene, and high in content of rearranged compounds. The ratio of Pr/Ph is more than 1, with tricyclic terpane C 21 > C 23 . These characteristics are still preserved after maturation. Moreover, during the sedimentation of the source rocks of T 3 x 2 –T 3 x 3 members, the supply of continental plants was low (TAR < 1, with regular sterane C 27 > C 29 , 1-MP/9-MP < 1). The source rocks of T 3 x 5 member were low in salinity (slightly low content of gammacerane and carotene), being different significantly from the other Upper Triassic source rocks. In addition, during the sedimentation of the source rocks of J1dn Member, the supply of continental plants was also low (regular sterane C 27 > C 29 , 1-MP/9-MP < 1), being quite different from that of J 1 l member. Through analysis of the difference in biomarkers, it is indicated that the sedimentary environment had changed from anoxic and brackish water during the Late Triassic to oxygen-rich and freshwater during the Early Jurassic in the Sichuan Basin. During this process, the types of organic matters had changed for several times.

通过对龙门山前陆盆地南段乐地1井上三叠统须家河组岩心的系统观察和描述,以前人对震积岩的研究为基础,探讨震积岩的分布特征以及与盆地构造活动的关系.震积岩主要分布在须家河组第二、第三和第四段,发育典型的由地震导致的软沉积物液化变形和脆性变形构造,包括液化砂岩脉、液化卷曲变形与混滑层、负载构造及球枕状构造、环形层理、震裂岩和微断层.认为这些软沉积物液化变形和脆性变形构造是由龙门山隆升构造引起的地震作用形成的.乐地1井中地震岩的分布特征表明龙门山前陆盆地南段在须家河组第二、第三和第四段时期构造活动强烈,并快速向南东方向推进.

贵州赤水地区位于四川盆地西南缘,晚白垩世时期该地区沉积了一套厚达1300m的陆相地层.本文通过地表露头的古流向野外观测和室内分析,详细研究赤水地区晚白垩世沉积充填过程及构造意义.赤水地区晚白垩世早期辫状河的古流向为自北东向南西,表明碎屑物源主要来自盆地北侧和东侧.根据物源、地层分布及区域地质背景推断,赤水地区晚白垩世的陆相沉积盆地属于陆内前陆盆地,陆内造山带位于盆地东侧.晚白垩世陆内前陆盆地的形成,可能受控于此阶段华南的构造挤压事件形成的陆内造山作用.

Southeastward strain transfer in the middle-southern Longmen Shan (LMS) thrust belt not only can promote the development of fault-related folds and earthquakes in the piedmont, but also affect the seismogenic capacity of the middle-southern LMS thrust belt. However, the detailed transfer process remains elusive. In this work, we combine structural profile re-analysis, sandbox modeling and seismic statistics to illustrate the strain transfer process. Our main results indicate that: (1) the thickness of the shallow detachment (e.g. Middle-Lower Triassic gypsum-salt strata) is probably the main factor for differences in southeastward strain transfer within the domain between the middle-southern LMS thrust belt and Weiyuan-Moxi anticline. This is also supported by our sandbox model; (2) the seismogenic capacity in the southern LMS thrust belt is probably proportional to the corresponding shortening of the Range Front Blind Thrust (REST). Thus, seismogenic capacity in the seismic gap zone is weaker than those of other segments of the southern LMS thrust belt, which is probably < Ms 7.0. (3) The weak seismogenic capacity (< Ms 7.0) and formation of the seismic gap is probably attributed to weak petrophysical properties and enhanced southeastward strain transfer. It is worth noting that the 1970 Dayi Ms 6.2 earthquake probably released most energy of the seismic gap. Further, this work also sheds light on the evaluation of seismic hazard in the LMS and other orogenic belts.

Objective The Yanyuan and Sichuan Basins,located at the southwestern margin of the Yangtze Block,are separated by the Kangdian Oldland.The provenance of the Upper Triassic sediments deposited in the Sichuan Basin has been extensively studied much based on detrital zircon UPb geochronology （Zhang et al,2016;Zhu et al.,2017;Yan et al.2019）.However,the provenance of the Upper

Over a five year period, the Longmen Shan thrust belt was the source of the 2008 Ms 8.0 Wenchuan earthquake and the 2013 Ms 7.0 Lushan earthquake, leaving a seismic gap between the seismogenic structures of these two earthquakes. In this study, we report on a trenching and dating program to assess the rupture behavior of the Shuangshi-Dachuan fault, as well as analyzing its geological significance, and discussing the seismic potential of the seismic gap. One paleoseismic event (5382-385 yr B.C.) and another possible event (1013-1560 yr A.D.) were identified in our study. Based on geological physiognomy (fault geometry and paleoseismic events, etc.) and geophysical marks etc, the Shuangshi-Dachuan fault in the seismic gap can be divided into two segments (a southern segment 1 and a northern segment 2). Based on six trenches across the Shuangshi-Dachuan fault in the seismic gap, using the event window method, at least four paleoseismic events are identified (120-435 yr B.P., 720-905 yr B.P., 2475-2717 yr B.P., 2335-3830 yr B.P. (closest to 3830 yr B.P.)). The change in characteristics such as strike, main stress, maximum dislocation of single paleoseismic events, and strike fault activity trace, from segment 1 to segment 2, reflect the character of the Longmen Shan thrust belt transition zone. Vertical displacements of single earthquakes from the six trenches in the seismic gap are similar and small (0.2-0.4 m), the reason for which may be that the seismic gap is a weak part in the upper crust of ductile rocks with low stress. The seismic capacity of the seismic gap is likely Ms < 7.0 and the probability that large earthquakes will occur in the near future is low.