Typical condensate reservoirs have been developed in the No.4 fault zone of the Shunbei area in the Tarim Basin. However, exploration expansion is restricted due to the unclear genetic mechanisms and main controlling factors of condensate accumulation. Through a comprehensive analysis of organic geochemical characteristics and the regional geological background, the genetic mechanisms and main controlling factors of condensate accumulation in the No.4 fault zone of the Shunbei area have been identified, and the following understandings are mainly obtained: (1) the condensate oil and gas reservoirs in the No.4 fault zone of the Shunbei area are mainly primary condensate reservoirs, and their formation is mainly affected by differential maturation of organic matter, multi-phase accumulation, and secondary alteration; (2) the overall secondary effects on the condensate oil and gas reservoirs in the Shunbei No.4 fault zone are relatively weak, however, the secondary effect experienced by the middle and southern sections is relatively stronger compared to the northern section; these secondary processes include oil cracking, gas invasion, and thermochemical sulfate reduction (TSR); and (3) the enrichment degree of condensate oil and gas reservoirs in the northern section of the Shunbei No.4 fault zone is significantly higher than in the middle and southern sections; the enrichment and high production of condensate oil and gas are mainly controlled by transport conditions and reservoir scale. Stronger fault activity, better transport conditions, larger reservoir size, and thinner gypsum-salt rock layers facilitate the upward migration of oil and gas along strike-slip faults, leading to higher production and enrichment of condensate.

The Tarim Basin is the largest superimposed and oil-bearing basin in China, presented as an episodic tectonic superposition in the Central uplift. Understanding hydrocarbon differential accumulation in the Central uplift requires a proper view of the evolution of the early Paleozoic carbonate platform. Through detailed twodimensional seismic interpretation, paleogeographic and paleotectonic reconstructions of the carbonate platform are performed. Tying hydrocarbon accumulation elements to the dynamic evolutionary process of the carbonate platform, this paper provides new insights into hydrocarbon differential accumulation in the Tazhong and Bachu uplifts. Due to ongoing compression from the south, the Hetian paleohigh and the Tazhong uplift initially formed in the Cambrian -Middle Ordovician carbonate platform interior in the latest Middle Ordovician. The climax of uplifting and northward tilting of preexisting paleohighs occurred in the latest Ordovician and latest Middle Devonian, respectively. The carbonate platform suffered polyphase exposures in these paleohighs and strike -slip faulting in the northern slope of the Tazhong uplift, forming favorable karst reservoirs and strike -slip fault -controlled reservoirs. Following the latest Permian uplifting of the northwestern Hetian paleohigh, the Bachu uplift nucleated in the northern Hetian paleohigh in the Cenozoic. The southwestern Hetian paleohigh was inverted into a southwest -dipping monocline. In the Bachu uplift, the allochthonous hydrocarbons from the southwestern Hetian paleohigh underwent episodic migration, accumulation, adjustment, and destruction during the evolution of these uninherited paleohighs. The hydrocarbons mainly remain in structuralstratigraphic traps in the southern margin of the Bachu uplift. Multiple periods of gentle tilting have occurred in the Tazhong uplift since the Late Devonian. Episodic migrating hydrocarbons from autochthonous and neighboring source rocks in the north are enriched in the northern flank of the inherited Tazhong uplift.

The Shunbei oil-and-gas field in the Tarim Basin features a typical strike-slip fault-controlled fractured-vuggy reservoir. The formation of these reservoirs is primarily influenced by fracturing related to structural stress during periods of fault activity. This contrasts with reservoir types such as matrix vugs controlled by original sedimentary facies and caves modified by karst. To study the development mechanism and distribution patterns of strike-slip fault-controlled reservoirs under the influence of multi-stage structural stress, comprehensive analysis of field observations, core samples, well logging data, seismic surveys, and drilling dynamic data was conducted to characterize the development characteristics of fault-controlled reservoirs. This included different strike-slip faults, different parts along a single strike-slip fault, and different stratigraphic levels vertically. Combined with stress field numerical modeling, multi-stage structural stress recovery was carried out to predict the main development periods and distribution patterns of fault-controlled reservoirs. Significant variations in internal stress states were observed across different segments during periods of strike-slip fault activity. Tensile stress predominated in pull-apart segments, resulting in predominantly tensile fractures, whereas compressional stress state in push-up segments led to a variety of fracture types. The fault-controlled fractures in the top of the Yijianfang Formation in the Shunbei area were mainly developed during episode Ⅲ of the Middle Caledonian period and the Late Caledonian-Early Hercynian period. Few fractures were developed during the Middle to Late Hercynian period and thereafter. Compared to the Shunbei No.1 fault, the Shunbei No.18 fault exhibited higher fracture opening degree and density with a large displacement. Strike-slip fault-controlled reservoirs exhibit a cluster-like structure. Structural differences of the reservoirs are influenced by internal stress states in different segments during fault activity. Pull-apart segments typically feature a large fault core-damage zone with more cavities and 'double-cluster' structures, whereas push-up segments display more diverse fault core-damage zones with greater separability and 'multi-cluster' structures. The stress intensity during the strike-slip fault activity controls the types and scale of reservoir spaces, with smaller fault zones dominated by fractures and larger fault zones developing extensive fault core-damage zone architectures. The scale of fault-controlled reservoirs is positively correlated with fault activity intensity. Early fault activity promotes significant fracture development, while later stages, characterized by increased burial depths, result in few newly derived fractures due to reduced rock susceptibility to fracturing.

The tectono-magmatic evolution of the North China Craton (NCC) plays a crucial role in understanding the Jurassic-Early Cretaceous (Yanshanian) intracontinental orogeny in East Asia. A holistic understanding of multi -phased deformation and magmatism in the NCC is greatly complicated by the sporadically distributed Mesozoic strata with significantly different stratigraphic associations in various zones. In this paper, we review the Jurassic-Early Cretaceous litho-stratigraphy with emphasis on unconformities to define a coherent chro-nostratigraphic framework of the entire NCC. Integrating available data concerning tectonic deformation, and geochemistry and fabric of igneous rocks into the well-established coherent chronostratigraphic framework, a four-stage tectonic evolutionary model of the NCC is proposed, providing new insights into the dynamics of the Yanshanian intracontinental orogeny in East Asia. The first stage concerns a N-S extension in the NCC during the Early-early Middle Jurassic (-200-170 Ma), expressed by the E-W striking brittle normal faults developed in the Lower-lower Middle Jurassic strata, and magmatism along the southern and northern margins of the NCC. It could be related to the post-orogenic extension after the deep continental subduction of the South China Block beneath the NCC. The second one is characterized by a N-S compression (i.e., Event A of the Yanshanian orogeny) in the late Middle Jurassic (-170-160 Ma), evidenced by the unconformity above the Lower-lower Middle Jurassic strata and the upper Middle Jurassic syn-tectonic deposition. The associated N-S directed thrusts and fault-related folds were mainly localized in the northern part of the NCC, possibly responding to the far-field compression related to the closure of the Mongol-Okhotsk Ocean. The third stage corresponds to a NW-SE compression (i.e., Event B of the Yanshanian orogeny) during the Late Jurassic-earliest Cretaceous (-160-135 Ma), illustrated by the NW-SE directed thrusts and the overprint of pre-existing N-S directed thrusts by the latter NW-SE directed thrusts. It was well recorded by the Upper Jurassic-lowermost Cretaceous syn-tectonic depo-sition and the unconformity above. This NW-SE compression in response to the flat slab subduction of the Paleo-Pacific Plate had influenced the entire NCC. However, the latest Middle-early Late Jurassic (-165-150 Ma) local NE-SW extension, recorded by ductile and brittle normal faults, magnetic lineation in granitic plutons, and magmatism that extended to Northeast China and its adjacent areas, also occurred in the northeastern part of the NCC. This could be related to tectonic transition from the N-S closure of the Mongol-Okhotsk Ocean to the NNW -directed subduction of the Paleo-Pacific Plate. In the latest stage during the Early Cretaceous (-135-115 Ma), the large-scale crustal extension, characterized by metamorphic core complexes, magmatism, graben or half -graben basins, occurred in a vast area extending more than 4000 km, from Transbaikalia, through the NCC, to the South China Block. It could be the consequence of the lithospheric thinning and the formation of the wide rift due to the southeastward stress relaxation of the NW-SE convergent East Asian continent as the slab rollback of the Paleo-Pacific Plate. These results provide a notable example of polyphase intra-plate deformation and magmatism paradigm in response to intracontinental orogeny with variable plate-boundary geodynamics.

Many Ordovician reservoirs discovered in the eastern section of Bachu-Maigaiti area ("Bamai area" for short) in the Tarim Basin are closely related to multi-stage active faults, making it the key to find oil and gas reservoirs in this area by identifying the source faults that cut through Cambrian gypsum-salt layers. Combined with the analysis of fault structure based on a large number of new seismic data and previous studies, the fault system in the eastern section of the Bamai area, especially the distribution and activity characteristics of strike slip faults are reunderstood. The results show that along with the migration and evolution of palaeo-uplift and the activities of large thrust fault zones in Bamai area, a series of high-angle and small-distance NE strike-slip faults that play a role of deformation and regulation are also developed, which together constitute the deformation tectonic system in the area. Two types of strike slip faults are developed in this area. One is superimposed and developed simultaneously or later with the NE and nearly EW Cambrian post-salt decollement zone of bruchfalten, with its strike consistent with that of the thrust fault belt, which is mainly distributed in the boundary and interior of the Hetian paleo-uplift. The other is developed in the compression-shortening zone confined by the large thrust fault belt, intersected with the nearly EW thrust fault belt at a large angle, and mainly distributed in the Hetian palaeo-uplift and Bachu faulted uplift. The former mainly formed in the late Hercynian period with weak local activities in the late Himalayan period, and the latter mainly formed in the late Himalayan period. The strike-slip faults superimposed with the Ordovician carbonate rocks that has experienced karst transformation in the middle and late Caledonian and early Hercynian are more conducive to the formation of effective fracture-karst vug reservoirs. They connect the upper and lower strata of the gypsum-salt layers, and their active period is consistent with the main hydrocarbon generation period of the deep subsalt source rocks, which is more conducive to transporting hydrocarbon source upward to the Ordovician system for accumulation. The large-scale reservoir located above the source and connected with two types of high-angle strike-slip faults is the favorable exploration direction of Ordovician.

随着高精度连片三维地震资料的采集,塔里木盆地克拉通内部发育的中小滑移距走滑断裂呈现出复杂的空间结构与构造样式.为此,以顺北12号断裂为研究对象,开展了顺北12号断裂及派生构造的三维空间结构、活动特征和活动期次的精细解析与成因机制分析.结果表明:(1)顺北地区主干走滑断裂自西向东挤压变形逐渐增强,其中顺北12号断裂处于NE向走滑断裂体系的过渡位置,构造样式上既发育西侧弱挤压断裂体系的"拉分-平移-压隆"三段式分段结构,也发育东侧强挤压断裂体系的"压脊构造".(2)顺北12号断裂碳酸盐岩顶面北部发育NE20°走向派生分支断裂,浅层发育沿下伏主干断裂走向展布的雁列正断层,上部雁列正断层活动强烈,连接形成扇形雁列带,下部主干断裂线性发育,从而形成了一种上部连片发育雁列正断层、下部发育高陡直立断裂的新的分层变形样式.(3)在盆缘动力背景影响下,顺北12号断裂及其派生分支经历了3期左行走滑活动:在加里东中期Ⅲ幕顺北12号断裂及其派生分支断裂初始活动;加里东晚期,深部断裂活化并相互影响,拖曳上覆地层形成第一期雁列正断层;海西中期,形成第二期雁列正断层.

The Cretaceous extensional province of the South China Block (SCB), and the decratonization-induced extension in the North China Block (NCB), were both controlled by the Late Mesozoic subduction of the Izanagi/Paleo-Pacific Plate. Different from the metamorphic core complexes exhuming deep crustal rocks of the NCB, extension of the SCB is expressed by numerous half-graben basins and detachment of upper-middle crustal rocks, but its mode and mechanism remain unclarified. At the westernmost of this extensional province, the Early Paleozoic Yuechengling-Miao'ershan Massif, composed of the ductilely deformed Yuechengling pluton and undeformed Miao'ershan pluton, records Late Mesozoic detachment and exhumation. Magnetic fabrics of the western Yuechengling pluton are consistent with structural fabrics, while the NE-SW trending magnetic lineation and NE-SW striking magnetic foliation of the Miao'ershan pluton and the undeformed Yuechengling pluton reflect a pre-existing magma flow structure. Integrating our structural observation, anisotropy of magnetic susceptibility (AMS) results with gravity modeling, we reveal the deep geometry of the extensional dome and restore the original structure before the Late Mesozoic Ziyuan detachment. The mode of extension argues for a single batholith split into two separate massifs, thinning the crust of the central SCB. The shallow-dipping Ziyuan detachment fault (10°-30°) may account for the large horizontal extension but low exhumation of mid-crustal rocks in the SCB, in contrast to the large exhumation of deep crustal rocks in the NCB.

Convergent plate margins could have an immediate impact on intraplate deformation in the adjacent sedimentary basin. In the Tarim Basin, a strike-slip fault network in the Guchengxu High is adjacent to the Tethys (northern Tibetan Plateau). This paper uses high-quality 3-D seismic data to unravel the geometry and kinematics of the strike-slip fault network and the genetic relationship with the Tethys tectonics. Within the fault network, the left-lateral NNE- and ENE-oriented strike-slip faults are a result of sequential evolution rather than conjugate faults. The sub-vertical ENE-oriented strike-slip faults are widely spaced with stepping-segmented geometry in the west, whereas they are relatively clustered with larger vertical throws close to the Cherchen fault. They were interpreted as a series of the Cherchen fault-related structures due to oblique blocking of the Tazhong Uplift and block deflection. It responded to the Late Ordovician Altyn Tagh/Tarim collisional orogeny and the Cherchen fault. The NNE-oriented strike-slip faults are characterized by underlying sub-vertical faults and two layers of overlying normal faults. These NNE-oriented strike-slip faults have large transversal compressional components, commonly presenting reverse drags on both sides of the underlying sub-vertical faults. These NNE-oriented faults initiated on pre-existing discontinuities (extensional joints) and offset the ENE-oriented ones when NNW-oriented stress was transmitted to plate interiors during this Late Ordovician orogeny. Afterward, two layers of overlying normal faults formed due to dragging of the covers during the Middle Silurian–Early Carboniferous reactivation and the Late Carboniferous–Early Permian inversion, in response to subduction of the Kunlun Ocean and opening of the Paleo-Tethys Ocean, respectively. The strike-slip fault network in plate interiors evolved as immediate responses to the Tethys tectonics at plate boundaries.

In response to the craton destruction, the North China Craton (NCC) underwent the Early Cretaceous extensional tectonics. During this period, the eastern NCC has also experienced numerous plutonism, volcanism, and extensional structures. Particularly, half-graben or graben, Early Cretaceous extensional domes, metamorphic core complex, and syn-kinematic plutons are widespread throughout the NCC and its surrounding area, with a peaking age of 125 Ma, pointing to a large-scale severe NW-SE extension. However, it remains unknown when and how the large-scale extension is initiated. To answer this key issue, we choose two plutons (Fengjiayu-Xibailianyu and Gubeikou plutons) with the age of early stage of the Early Cretaceous (130-127 Ma) as the target of this study. The Fengjiayu-Xibailianyu pluton is close to, while the Gubeikou pluton is far away from the Early Cretaceous intensive extensional region. A multidisciplinary study, including structural geology, anisotropy of magnetic susceptibility (AMS), and gravity modeling, has been carried out on these two plutons to reveal the tectonic regime coeval with their emplacement. Both of these two plutons share similar features of concentric magnetic foliations and variable magnetic lineations which are decoupled with the ductile fabric in their country rocks. Accordingly, we considered that they intruded in a permissive way at a weak extension regime during the Early Cretaceous (130-127 Ma), just before the Late Mesozoic peak of the magma flare-up and large-scale extensional tectonics of the NCC. Combined with our previous works, the Early Cretaceous NW-SE trending extension in NCC was further subdivided into the early-stage weak extension during 130-127 Ma and the late-stage intensive extension during 127-110 Ma, namely the large-scale extension initiated after 127 Ma. The early-stage extension could be ascribed to the westward subduction of the Izanagi plate under the Eurasian continent.

To understand the post-orogenic tectonics related to collision between the North China Craton (NCC) and the South China Block (SCB), the Northern Sulu massif is a representative area. It experienced a complex evolution marked by exhumation of ultra-high-pressure metamorphism rocks, migmatization, and alkaline magmatism in the Latest Triassic, and felsic magmatism in the Late Jurassic. In this contribution, we carried out a combined study including structural analysis, anisotropy of magnetic susceptibility (AMS), and gravity survey on the Northern Sulu massif. According to our structural analysis, it is interpreted as an extensional dome, exhibiting dominantly SE-dipping foliations in its east and center and NW-dipping ones closer to its northwestern margin, NW-SE mineral and stretching lineations, and top-to-the-NW kinematics. The Latest Triassic pyroxene syenite has dominantly SE-dipping mesoscopic/magnetic foliations, NW-SE magnetic lineations, and wedge shape at depth, and the Latest Triassic quartz syenite has variable magnetic fabric. Considering geometric relations of plutons and country rocks, the former is a "syn-kinematic" pluton, while the latter post-dates the regional tectonics, constraining the timing of the top-to-the-NW shearing at 220-210 Ma. Compared with the syn-orogenic tectonic events, the Latest Triassic ductile deformation points to a NW-SE extension related to lithospheric delamination. Late Jurassic isotropic monzogranite is characterized by "onion-skin" magnetic foliations with NE-SW trending magnetic lineations, and NE- or SW-ward decrease of thickness at depth. On the basis of regional understanding, we link its emplacement with the Late Jurassic NE-SW extensional tectonics attributed to the oblique subduction of the Paleo-Pacific plate. Such two episodes of crustal extensions with magmatism reformed the crustal architecture of the SE-margin of the NCC, which considerably facilitated stress-transmission from plate-boundary to intraplate during the development of subsequent Late Mesozoic intracontinental deformations.

SUMMARY Penetrative petro-fabrics in plutons, particularly late-stage solid-state fabrics, are usually considered to record regional tectonism. However, these fabrics are fundamentally ambiguous to correlate with magma-chamber processes or regional tectonics. Understanding the processes of fabric formation requires a proper understanding of pluton formation and emplacement mechanism. In this paper, we provide a case study of a transition from magma chamber-related magmatic to solid-state fabrics within the Late Triassic granitic Dushan pluton (North China) based on a multidisciplinary investigation of its emplacement mechanism, including structural geology, isotope chronology, AMS data measurement, and gravity modeling. The Dushan pluton varies in a southwest direction from a megascopically isotropic monzogranite in the northeast to an arc-shaped gneissic monzogranite with locally mylonitic zones along the southwest margin. The compatible outward dipping mesoscopic and magnetic susceptibility foliations define a dome-like roof with a NE-SW long axis. Considering the absence of similar penetrative fabrics in the country rocks, a continuum of magma chamber-related fabric variations within the pluton, from magmatic to solid-state conditions, probably formed during pluton emplacement. Gravity modeling suggests that the Dushan pluton has a NE-SW trending tongue-like shape with a northeast positioned root. We propose a model in which the Dushan pluton was emplaced through a northeast feeder zone, beginning probably as a sill then evolving by inflation via several magma batches. Later magma batches inflated the country rocks to form the final pluton. Magma inflation deformed the former semi-solid magma, forming a curved gneissic to mylonitic foliation along the southwest margin of the pluton. Several multidisciplinary studies show that the North China Craton (NCC) experienced a Late Triassic regional crustal extension attending the Dushan pluton emplacement. Both mesoscopic and magnetic susceptibility fabrics of the pluton could be more related to magmatic process rather than regional tectonics, implying that such fabrics within plutons need to be used with caution for inferring regional tectonics.

中生代以来, 华北克拉通岩石圈发生大规模减薄, 岩石圈地幔的物理、化学性质发生显著改变, 这一过程通常被称为华北克拉通破坏. 目前在华北克拉通东部大规模发育的岩浆岩是岩石圈深部减薄过程在浅部的重要响应, 也是克拉通破坏在浅部的直接表现. 岩体侵位机制和侵位过程与大地构造背景密切相关, 并记录同期区域大地构造信息. 15年来, 通过对华北克拉通东部不同岩浆发育阶段(晚三叠世、早侏罗世、晚侏罗世、早白垩世早期及早白垩世晚期) 22个花岗岩体开展磁化率各向异性(AMS)的研究, 反演岩体的就位过程; 结合早白垩世早期广泛发育的变质核杂岩, 探讨岩体侵位的构造背景, 进一步约束华北克拉通在不同阶段的构造背景及其与克拉通破坏的相关性. 其中, 晚三叠世、早侏罗世和晚侏罗世岩体均具有一致的N(E)-S(W)向的磁线理, 早白垩世早期岩体和变质核杂岩以NW-SE向(磁)线理为主, 早白垩世晚期岩体的磁线理则比较分散. 结合区域构造, 我们推断晚三叠世、早侏罗世和晚侏罗世岩体侵位受区域N(E)-S(W)向弱伸展构造体系的控制, 早白垩世早期岩体侵位则受区域NW-SE向伸展构造体系的控制, 而早白垩世晚期岩体就位与先期浅表弱伸展已经产生空间相关. 总而言之, 华北克拉通中生代伸展构造经历了从N(E)-S(W)向NW-SE的转变, 并体现出阶段性由弱渐强的表现. 上述伸展构造发育方向的转变可能代表蒙古-鄂霍茨克带和古太平洋板块与欧亚大陆东部相互作用过程.

The Lushun-Dalian area of the South Liaodong Peninsula, in NE China, located in the SE margin of the North China Craton (NCC) exposes a suite of Middle-Late Proterozoic low-grade metamorphic sedimentary rocks which can be divided into a lower competent layer, a middle incompetent layer, and an upper competent layer on the basis of lithology and deformation style. Two stages of deformation recorded both in the metasedimentary rocks and a magmatic complex intruded in them indicate that the Lushun-Dalian area is a key region to decipher the Triassic–Jurassic tectonic evolution of the eastern NCC. The earliest D1 deformation mylonitized the magmatic complex and thrusted it northeastward over the low-grade metasedimentary rocks, in which a series of NE-verging folds and NE-directed brittle thrust faults developed. The D2 deformation erased the D1 fabrics in the incompetent layer by a top-to-the-NW ductile shearing and refolded the D1 fabrics in the lower and upper competent units, producing a series of km-scale SW-plunging folds. New zircon secondary ion mass spectrometry and laser ablation–inductively coupled plasma–mass spectrometry U-Pb ages from the magmatic complex and the granite porphyry dikes intruded in it, combined with the unconformity between the low-grade metasedimentary rocks and the Early Cretaceous volcanic rocks, indicate that D1 and D2 occurred after 211 Ma and before the Early Cretaceous. The decrease of the deformation intensity of D1 and D2 from the Lushun-Dalian area toward the interior of the NCC in the NE and NW directions suggests that D1 was the structural response in the overriding plate to the NCC-South China Block convergence during the Late Triassic to Early Jurassic, and D2 was the structural response to the northwestward subduction of the Paleo–Pacific plate beneath the NCC in the Middle-Late Jurassic. The superimposition of D2 on D1 recorded a significant tectonic transformation from the nearly E-W–trending Tethysian domain to the NE-SW–trending Pacific domain.

The Yanshan fold and thrust belt (YFTB) was built up by multiple contractional events, namely the ?Yanshan Movement?, which was traditionally subdivided into the ?Yanshan-A? and ?Yanshan-B?. In contrast with the better constraint on ?Yanshan-B? (ca.140 Ma), the timing of ?Yanshan-A? is still in dispute. The Middle Jurassic contraction (172?160 Ma) was widely accepted, however, whether this contraction can last into 150 Ma is still unclear. In this article, to clarify the Late Jurassic tectonic regime in the YFTB, a multidisciplinary study, including structural geology, Anisotropy of Magnetic Susceptibility (AMS), gravity modeling, geochronology, and geochemistry, has been carried out to investigate the emplacement mechanism of the Siganding pluton (ca. 161?157 Ma) in the northern Beijing area. The magma was predominantly derived from the Precambrian continental lower crust. The magnetic foliations are pluton margin-parallel and outward dipping, resembling the fabric pattern of magmatic dome. The NE-SW striking magnetic lineations and NW-SE linear feeder zones revealed by gravity modeling indicate that the emplacement of the Siganding pluton was controlled by a weak NE-SW crustal stretching interpreted as a regional tectonic extension. Considering that the Late Jurassic (164?153 Ma) NE-SW oriented extension structures are not only documented in the YFTB, but also the entire eastern NCC, hereby we propose that the ?Yanshan-A? is constrained at 172?164 Ma, instead of a wide range from the Middle Jurassic to Late Jurassic (172?150 Ma) as argued by previous workers. The extension could be ascribed to the oblique subduction of the Izanagi plate.

To better understand Late Triassic tectonic setting in the northern North China Craton (NCC), the emplacement mechanism of the Wangtufang pluton, which recorded the synmagmatic regional tectonic signature, has been investigated. Zircon U-Pb ages, and Hf isotopic data, and whole-rock geochemical analyses suggest that the Late Triassic Wangtufang pluton composed of syenogranite and diorite is derived from partial melting of lower crust with some depleted mantle components. Both the syenogranite and diorite appear isotropic. Anisotropy of magnetic susceptibility and gravity studies have been carried out to characterize internal fabrics and shape of the pluton. The diorite forms just thin remnants above the syenogranite. The syenogranite with a series of NW-SE trending dykes intruded into the diorite and its country rocks. In the syenogranite, the gently dipping magnetic foliations strike nearly parallel to the pluton border. The shallow plunging magnetic lineations mainly strike NE-SW. Combining NE-SW trending elongated subsurface shape with central root, unflat bottom, and moderate to high-inward dipping sidewalls, the syenogranite could be considered as a lopolith-like intrusion. The syenogranite was likely emplaced by inflation of magma pulses from its central conduit and built up by floor depression. Emplacement of the syenogranite was in an extensional setting, considering: (1) the NE-SW striking magnetic lineation, (2) the NE-SW trending elongated subsurface pluton shape, and (3) the orthogonal NW-SE striking syenogranitic dykes considered as tension gashes during the NE-SW trending extension. The Wangtufang pluton provides reliable arguments to the Late Triassic intracontinental extensional setting already suggested in the northern NCC.

To better understand the Late Triassic tectonic setting in the northern North China Craton (NCC), a multidisciplinary investigation, including structural geology, geochronology, anisotropy of magnetic susceptibility (AMS) and gravity modeling, has been carried out in the Dushan pluton. The Dushan pluton consists of monzogranite and biotite-rich facies along the pluton margin without sharp contact between them. The granite varies southwestwards from isotropic texture to arcuate gneissic structures, with locally mylonitic structures. The intensity of solid-state deformation increases southwestwards across the pluton, leaving preserved magmatic fabrics in the northeastern part. The compatible outward dipping magmatic and solid-state magnetic fabrics, together with mesoscopic fabrics, define an elliptic dome-like pattern with a NE-SW oriented long axis, despite the fabrics dip inwards in the southeastern margin of the pluton. Combining gravity modeling, the Dushan pluton presents an overall tabular or tongue-like shape with a northeastern root. The magnetic lineations nearly strike NE-SW, concordant with the stretching lineations observed in the mylonitic zones. We propose the emplacement mode that the Dushan pluton emplaced southwards through the feeder zone in its northeast, beginning probably with a sill. The later successive magma batches may laterally and upwardly inflate, deform and even recrystallize the former cool-down magma. This inflation forms an arcuate, gneissic to mylonitic foliation in the southwestern margin. The Dushan pluton is considered as typically post-tectonic in emplacement, recording a Late Triassic post-tectonic setting of the northern NCC.

中国中东部晚中生代伸展构造十分显著,表现为大量发育伸展成因的穹隆构造和地堑-半地堑盆地.对这些伸展穹隆系统的分析、归纳和总结,将中国中东部早白垩世伸展构造发育区划分为:华北西部带、华北东部带、华北南缘及秦岭-大别带和华南内陆带.区域上,这些伸展构造均具有NW-SE的伸展方向,与蒙古及俄罗斯泛贝加尔-鄂霍茨克带一同构成了全球最大的大陆岩石圈伸展地区.这些伸展构造使中下地壳的结构发生了强烈的改造,并使一些中深变质岩出露到地表.在华北地区,这期伸展构造具有对称性的特点,即华北西部带向NW拆离,相关的岩石变形大体上具有上部向SE的运动学特征;而华北东部带向SE拆离,伸展穹隆主体具有上部向NW的运动学特征.同位素年代学研究揭示伸展穹隆形成的峰期时间十分相近:集中在130～120 Ma之间.高大地热流值背景所代表的岩石圈伸展环境,与地球化学研究结果所揭示的大规模壳-幔作用具有非常好的耦合性,并诱发了我国中东部晚中生代岩浆-热液活动及其相关大规模的成矿作用.中东部的成矿带与同时代的伸展构造具有很好的吻合性.

Integrated 2‐D and 3‐D seismic data sets reveal that a WNW trending complex anticlinal belt (the Tazhong Uplift) was cut roughly perpendicularly by a series of NNE oriented strike‐slip faults in the central Tarim Basin, NW China. Through detailed interpretation of the internal architecture of the Tazhong Uplift and the structural characteristics of the strike‐slip faults, the timing of their movements was determined. Based upon their geometric relationship and coeval movement, we propose an integrated model for the evolution of both the Tazhong Uplift and the strike‐slip fault system. Initially, the Tazhong Uplift formed perpendicular to the NNE oriented compression that responded to the collision between the Tarim block and the western Kunlun terrane in the latest Middle Ordovician. Meanwhile, regional joints formed parallel to the maximum compression, that is, perpendicular to the Tazhong Uplift. In the latest Ordovician, northward compression caused the uplifting climax of the Tazhong Uplift in response to the collision between the Tarim block and the coherent eastern Kunlun‐Altyn Tagh‐Qaidam‐Qilian terrane. Under such a northward compression, the resolved shear stress on the NNE trending joints formed the transpressional strike‐slip faults. Afterward, the Tazhong Uplift tilted northward during the ongoing subduction from the Kunlun Ocean, which lasted until the latest Middle Devonian. The negative flower structures formed along the preexisting transpressional strike‐slip faults due to the dragging of the overlying covers in the latest Middle Devonian. The data and evolution model not only unveil the formation mechanism of the Tazhong Uplift and the associated strike‐slip faults but also provide further constraints on the evolutionary age of the Proto‐Tethys Ocean.

To obtain the state of in-situ stress during the exploration of dense gas reservoir under Tarim Basin，the anelastic strain recovery(ASR) and the methods of drilling induced tensile fractures(DITF) were applied to measure the in-situ stress at depth of 7 km. The results show that the maximum principle stress is close to vertical and the medium and the minimum principle stresses are close to horizontal in SN-X well at 6 293–6 955 m depth. The orientation of maximum horizontal principal stress is NE51°–NE79°. The normal faulting stress regime exists in the inner Tarim Basin caused possibly by the stress releasing after the orogenic period or the escaping structures of Tarim basin by the long distance effect of Himalaya collisional orogeny. The effectiveness of ASR method at the ultra-depth was confirmed by the close results from the ASR and DITF methods. The ASR method has the advantages of low cost，high efficiency，and no depth and temperature limitation，and hence，will have broad prospect of application at ultra-depth in scientific drilling，unconventional oil and gas exploration and geothermal development.

Based on the structural interpretation and the analysis of 2 D/3D seismic data,it is identified that NE-trending/NEE-trending strike-slip fault zones are distributed in northern slope of Tazhong Uplift, and six identification marks of strike-slip fault in seismic slices and sections are summarized. Three types of strike-slip fault system which superimposed in space are developed, including compresso-shear faults(end of Middle Ordovician to Silurian),tenso-shear faults (Late Devonian to Early Carboniferous) and thrust faults(Late Permian). It is concluded that the development of fractured reservoir and fractured-vuggy reservoir was controled by the intensity of fault deformation,and the development of high-quality fractured-vuggy reservoir was dominated by the segmentation of strike-slip faults. It is suggested that the fracture zones with strong deformation, the pull-apart structure, and the trough fault zone where superimposed reformation by later faults and with beading seismic anomalies are favorable targets for exploring large-scale natural gas reservoir of Ordovician.