塔里木盆地南部玛东早古生代褶皱-冲断带

玛东褶皱-冲断带位于塔里木盆地南部,走向NE-SW,由NW向SE方向冲断。褶皱冲断带发育于寒武-奥陶系,以中寒武统膏-盐层为主滑脱面。中志留统及其以上地层不整合于褶皱冲断带之上。它是世界上保存最好的早古生代褶皱冲断带之一。根据卷入变形最新地层、不整合于褶皱-冲断带之上的最老地层和上奥陶统上部的生长地层,玛东褶皱-冲断带的变形时间为晚奥陶世-早志留世。玛东褶皱-冲断带与其东南侧的塘南褶皱-冲断带同为塔里木盆地南缘早古生代前陆褶皱-冲断带的组成部分,塘南褶皱-冲断带是该早古生代前陆褶皱-冲断带主体的残余,其向NW的主冲断方向代表该前陆褶皱-冲断带的主冲断方向;玛东褶皱-冲断带是该早古生代前陆褶皱-冲断带的前锋,其向SE的冲断具有反冲性质。它们是昆仑早古生代造山作用的重要记录,也是昆仑早古生代碰撞造山带的组成部分,现今保存最好的部分。     

Distribution of Palaeozoic tectonic superimposed unconformities in the Tarim Basin,NW China: significance for the evolution of palaeogeomorphology and sedimentary response

Seismic and drilling well data were used to examine the occurrence of multiple stratigraphic unconformities in the Tarim Basin, NW China. The Early Cambrian, the Late Ordovician and the late Middle Devonian unconformities constitute three important tectonic sequence boundaries within the Palaeozoic succession. In the Tazhong, Tabei, Tadong uplifts and the southwestern Tarim palaeo‐uplift, unconformities obviously belong to superimposed unconformities. A superimposed unconformity is formed by superimposition of unconformities of multiple periods. Areas where superimposed unconformities develop are shown as composite belts of multiple tectonic unconformities, and as higher uplift areas of palaeo‐uplifts in palaeogeomorphologic units. The contact relationship of unconformities in the lower uplift areas is indicative of truncation‐overlap. A slope belt is located below the uplift areas, and the main and secondary unconformities are characterized by local onlap reflection on seismic profiles. The regional dynamics controlled the palaeotectonic setting of the Palaeozoic rocks in the Tarim Basin and the origin and evolution of the basin constrained deposition. From the Sinian to the Cambrian, the Tarim landmass and its surrounding areas belonged to an extensional tectonic setting. Since the Late Ordovician, the neighbouring north Kunlun Ocean and Altyn Ocean was transformed from a spreading ocean basin to a closed compressional setting. The maximum compression was attained in the Late Ordovician. The formation of a tectonic palaeogeomorphologic evolution succession from a cratonic margin aulacogen depression to a peripheral foreland basin in the Early Caledonian cycle controlled the deposition of platform, platform margin, and deep‐water basin. Tectonic uplift during the Late Ordovician resulted in a shallower basin which was followed by substantial erosion. Subsequently, a cratonic depression and peripheral or back‐arc foreland basin began their development in the Silurian to Early–Middle Devonian interval. In this period, the Tabei Uplift, the Northern Depression and the southern Tarim palaeo‐uplift showed obvious control on depositional systems, including onshore slope, shelf and deep‐water basin. The southern Tarim Plate was in a continuous continental compressional setting after collision, whereas the southern Tianshan Ocean began to close in the Early Ordovician and was completely closed by the Middle Devonian. At the same time, further compression from peripheral tectonic units in the eastern and southern parts of the Tarim Basin led to the expansion of palaeo‐uplift in the Late Devonian–Early Carboniferous interval, and the connection of the Tabei Uplift and Tadong Uplift, thus controlling onshore, fluvial delta, clastic coast, lagoon‐bay and shallow marine deposition. Copyright © 2015 John Wiley & Sons, Ltd.     

阿拉善地块南缘古生代花岗岩类研究进展

阿拉善地块处于华北克拉通,塔里木克拉通和祁连造山带的交汇处,其南缘古生代花岗岩广泛分布。结合近年来阿拉善南缘古生代花岗岩研究成果,从锆石U-Pb年代学和地球化学等方面进行分析总结,认为阿拉善南缘早古生代花岗岩主要受控于祁连造山带的构造演化,其岩浆活动可分为两期,中奥陶世—早志留世和中志留世—早泥盆世,前者处于俯冲环境,后者为后碰撞伸展环境;晚古生代花岗岩仅零星出露于龙首山地区,岩石地球化学特征与宗乃山—沙拉扎山构造带花岗岩相似,与中亚造山带的构造演化相关。并对目前研究中存在的问题和未来研究的方向提出了建议。     

塔里木盆地寒武纪构造-沉积环境与原型盆地演化

寒武系是塔里木盆地当前油气增储上产的重点层系,恢复寒武纪的盆地原型是油气勘探的重要基础。利用最新的钻井、地震及露头资料,以沉积相为研究实体,将盆地充填与周缘构造演化相结合,由点→线→面进行分析,恢复了塔里木盆地寒武纪不同时期的构造-沉积环境,并建立了相应的盆地充填演化模式。塔里木盆地寒武纪经历了一次完整的海侵-海退旋回,包括早寒武世早期快速海侵→中寒武世海退、晚寒武世缓慢海侵→寒武纪末海退两个次级旋回,分别对应沉积演化的2个阶段：塔西克拉通内坳陷早寒武世的碎屑滨岸-陆棚相→局限台地相→中寒武世的蒸发台地相,晚寒武世的局限台地相→寒武纪末期的台地暴露不整合;塔东克拉通边缘坳陷为深水盆地相,经历了硅质泥岩→泥岩与灰岩薄互层→碳酸盐岩的岩相演化。寒武纪塔里木原型盆地特征及演化主要受控于Rodinia超大陆的裂解,其构造-沉积格局经历了由震旦纪末的南北分异格局向中-晚寒武世的东西分异格局的演变。     

Intra-platform tectono-sedimentary response to geodynamic transition along the margin of the Tarim Basin,NW China

The Tarim Basin has experienced three tectonic evolutionary phases from the Cambrian to Ordovician: (1) Regional extension from the late Neoproterozoic to Mid-Early Cambrian, (2) Relatively weak regional compression from the Late Cambrian to Mid-Early Ordovician, and (3) Regional compression during the Late Ordovician. Intra-platform tectonic and sedimentary characteristics indicate a clear linkage to the tectonic evolution of the basin margin during early Paleozoic time. During the Cambrian, small intra-platform rift-related depressions formed during an extensional setting. During the Mid-Early Ordovician, a transition from extension to compression caused formation of the Tazhong and Tabei paleo-uplifts and major unconformities T₇⁴ (base of the Late Ordovician). The evolving paleo-geomorphology led to differentiation of sedimentary facies, and numerous intra-platform shoals formed during deposition of the Early Ordovician Yingshan Formation. During the Late Ordovician, regional compression began, which changed the platform margin slopes into four slopes that surrounded the three isolated island uplifts of Tabei, Tazhong, and Tangnan in the Late Ordovician. Simultaneously, the basin margin dynamic conditions also changed the relative sea level and filling pattern of the basin. In the Early and Middle Cambrian, the Tarim Basin mainly developed a progradational ramp-type platform due to relative sea level fall. From the Late Cambrian to Early Ordovician the relative sea level began to rise, resulting in an aggradational—retrograding rimmed margins-type platform. In the Late Ordovician, along with a further rise in relative sea level, the basin mainly developed isolated platform.     

中亚褶皱区构造演化问题———俄罗斯学者近年研究成果评价

摘　 要　 俄罗斯地质学者把中亚褶皱区划分为两类构造区：镶嵌构造区和线状构造区。近年 来的研究认为前者是由于陆缘增生作用而形成的,增生作用发生于晚里菲,中—晚寒武世, 中—晚奥陶世和中—晚志留世;后者包括华力西和印支褶皱带,是大陆碰撞的产物。镶嵌构 造区和线状构造区的演化分别与古亚洲洋和古特提斯洋有关。由于对我国地质文献缺乏较全 面的了解,他们的某些结论例如内蒙古洋在晚古生代到早中生代的存在和古亚洲洋的性质及 演化等问题都是不妥的,作者将对此进行讨论。     

塔里木盆地古生代重要演化阶段的古构造格局与古地理演化

塔里木盆地在古生代经历了中-晚奥陶世、晚奥陶世末、中泥盆世末等多个重要的盆地变革期,形成了多个重要的不整合,盆地构造古地理发生了重要的变化。中、晚奥陶世盆地的变革形成了由巴楚古斜坡-塔中隆起-和田河隆起构成的大型古隆起带、相对沉降的北部坳陷带以及由于挤压挠曲沉降形成的塘古孜巴斯坳陷带。中部古隆起带制约着晚奥陶世东窄西宽的弧立碳酸盐岩台地体系的发育,而开始形成于震旦纪的满加尔拗拉槽及东南侧的塘古孜巴斯坳陷接受了巨厚的中、晚奥陶世重力流沉积。奥陶纪末的盆地变革形成了北东东向展布的西南-东南缘和西北缘的强烈隆起带,总体的古构造地貌控制着早志留世北东东向展布的滨浅海陆源碎屑盆地的沉积格局。中泥盆纪世末期的盆地强烈隆升并遭受了夷平化的剥蚀作用,形成了大范围分布的角度不整合面,并以塔北隆起和塔东隆起的强烈抬升为显著特征。盆地古构造地貌从东低西高转为东高、西低,制约着晚泥盆和早石炭世由东向西南方向从滨岸到浅海的古地理分布。中、晚奥陶世主要不整合及其剥蚀量的分布反映出北昆仑向北碰撞和挤入是造成盆地南缘、东南缘及盆内隆起的主要原因。南天山洋的俯冲、碰撞在奥陶世末至早志留世已对盆地西北缘产生影响,导致塔北英买力隆起的抬升和遭受剥蚀。     

新疆东准噶尔卡拉麦里蛇绿岩带两侧志留系—石炭系沉积和构造特征分析及其意义

卡拉麦里蛇绿岩带位于新疆准噶尔盆地东北缘,查明卡拉麦里蛇绿岩所代表的古洋盆形成和闭合时代,是新疆东准噶尔乃至古亚洲洋演化历史的关键地质问题之一。本文通过对蛇绿岩带两侧志留—石炭系的岩石组合、结构构造、接触关系以及生物化石等沉积-构造特征的对比分析,揭示卡拉麦里构造带古生代的构造演化。在卡拉麦里蛇绿岩带北侧,广泛发育上志留统、下泥盆统与中—上奥陶统和加里东期花岗岩的角度不整合,普遍缺失下志留统,不整合面之下的奥陶系为变质达绿片岩相的安山岩为主,而在蛇绿岩带南北两侧的中、上志留统—泥盆系—下石炭统沉积体系特征相似,可以对比:地层间整合接触,产状平缓,褶皱、断裂构造和变质作用均不发育,主要为开阔的短轴背斜、向斜,与卡拉麦里蛇绿混杂岩带中的强变形构造明显不同;岩石组合都以火山碎屑岩为主,多见交错层理等沉积构造,产门类众多的动植物化石,反映了滨—浅海相的沉积环境。以上说明,卡拉麦里构造带晚古生代并不存在一个开阔的大洋,卡拉麦里蛇绿岩所代表的古洋盆在中志留世之前已经闭合。     

阿尔金断裂两侧早古生代沉积建造与构造演化

阿尔金断裂两侧地质体能否对比,是中国西部地质领域里的重大科学问题,长期存在争议。以沉积建造和地质构造为基础,结合古生物和古地磁资料,对比分析早古生代阿尔金断裂两侧地质特点,认为早古生代阿尔金断裂两侧的岩相古地理及其他地质特征都具有很大差别:1）早寒武世塔里木陆块主要是伸展环境,缺少火山活动,祁连地区主要是收缩环境,发育火山活动;中寒武世塔里木北缘深水盆地里普遍出现含磷钒铀沉积,祁连地区主要形成火山岩及蛇绿岩;寒武纪中晚期柴达木北缘出现红色泥岩建造,而塔里木无论是盆地区还是盆地边缘,均缺少这套沉积;奥陶纪,祁连地区继承寒武纪构造特点,塔里木则转化为收缩环境;志留纪,塔里木南北两侧形成弧后扩张盆地,祁连地区俯冲作用基本消失,南祁连形成弧后海相前陆盆地。2）寒武纪至奥陶纪塔里木、柴达木、祁连地区生物分别具有亚—奥生物区、华北生物区和华北与华南型混生特点;中晚志留世塔里木和祁连地区分别为温带和亚热带—温带生物特点。3）寒武纪塔里木、柴达木—中祁连及阿拉善等陆块位于南半球低纬度地区;奥陶纪塔里木明显南移,阿拉善、柴达木徘徊在赤道附近;志留纪到泥盆纪,塔里木北移大于33°,柴达木与阿拉善分别北移约5°和10°;各陆块有明显不同的运动轨迹。4）寒武纪阿尔金地块漂浮于阿尔金洋中,寒武纪晚期开始阿尔金洋向两侧陆块俯冲后消亡。因此,早古生代阿尔金断裂两侧具有完全不同的岩相古地理特征,应当使用不同的思路和方法进行资源勘查。     

东秦岭古生代生物古地理

秦岭褶皱带位于华北板块和扬子板块结合部位,其在河南省内的部分多划为东秦岭。东秦岭以商南-镇平缝合带分为东秦岭北部和东秦岭南部。东秦岭古生代生物古地理演变可以划分为6个阶段。在寒武纪至中奥陶世早期,东秦岭北部二郎坪海槽的寒武纪放射虫和早奥陶世牙形石与东秦岭南部淅川陆棚北部的寒武纪三叶虫、早奥陶世牙形石和头足类属华南生物省,而淅川陆棚南部的寒武纪三叶虫和早奥陶世牙形石属于华南生物省,兼有华北生物省分子。在中奥陶世晚期至奥陶纪末,二郎坪海槽的腹足类、头足类和珊瑚与淅川陆棚的牙形石、珊瑚、腕足类、头足类和三叶虫均属华北生物省。在早志留世,二郎坪海槽的珊瑚与淅川陆棚的笔石属华南生物省。在中志留世至早泥盆世,东秦岭未发现古生物化石,很可能为陆地,并与华北陆块联为一体。在中泥盆世至早石炭世,东秦岭北部柿树园海槽与东秦岭南部南湾海槽的孢子及淅川陆棚的晚泥盆世珊瑚、腕足类和古植物及早石炭世蜓属华南生物省。晚石炭世至二叠纪末,柿树园海槽的孢子见于华北生物省,东秦岭南部缺乏海相沉积。总之,在古生代,东秦岭经历了由华南生物省→华北生物省→华南生物省→华北陆→华南生物省→华北生物省6个阶段,组成3个演变旋回。东秦岭北部和南部生物古地理具有明显的演变方向的统一性和演变时间的相似性。     

塔里木盆地玉北构造带断层特征及其裂缝分析

塔里木盆地玉北构造带形成于加里东中晚期, 主要断裂以挤压逆冲为主, 早期形成断层传播褶皱样式, 断层总体终止于石炭系/奥陶系不整合面之下.该地区奥陶系碳酸盐岩储层易发育断层伴生裂缝和褶皱调节性裂缝, 主要分布在膝褶带和断层传播褶皱区.海西晚期玉北地区断裂重新活动, 仍以挤压为主形成三角剪切样式, 但断层位移量并不大, 该时期玉北构造带基本定型, 储层裂缝易发育在三角剪切变形区.喜马拉雅期玉北地区存在微弱构造变形, 玉北构造带主要受到构造的叠加改造.新生代青藏高原向东的扩张产生北东-南西向的构造应力场, 使得北东-南西向的玉北断裂带具有开启性, 对玉北地区油气调整和聚集会有一定的影响.     

Accumulation and Reformation of Silurian Reservoir in the Northern Tarim Basin

Silurian sandstone in Tarim Basin has good reservoir properties and active oil and gas shows, especially thick widely-distributed bituminous sandstone. Currently, the Silurian was found containing both bitumen and conventional reservoirs, with petroleum originating from terrestrial and marine source rocks. The diversity of their distribution was the result of "three sources, three stages" accumulation and adjustment processes. "Three sources" refers to two sets of marine rocks in Cambrian and Middle-Upper Ordovician, and a set of terrestrial rock formed in Triassic in the Kuqa depression. "Three stages" represents three stages of accumulation, adjustment and reformation occurring in Late Caledonian, Late Hercynian and Late Himalayan, respectively. The study suggests that the Silurian bitumen is remnants of oil generated from Cambrian and Ordovician source rocks and accumulated in the sandstone reservoir during Late Caledonian-Early Hercynian and Late Hercynian stages, and then damaged by the subsequent two stages of tectonic uplift movements in Early Hercynian and Pre-Triassic. The authors presumed that the primary paleo-reservoirs formed during these two stages might be preserved in the Silurian in the southern deep part of the Tabei area. Except for the Yingmaili area where the Triassic terrestrial oil was from the Kuqa Depression during Late Himalayan Stage, all movable oil reservoirs originated from marine sources. They were secondary accumulations from underlying Ordovician after structure reverse during the Yanshan-Himalayan stage. Oil/gas shows mixed-source characteristics, and was mainly from Middle-Upper Ordovician. The complexity and diversity of the Silurian marine primary properties were just defined by these three stages of oil-gas charging and tectonic movements in the Tabei area.     

塔里木盆地塔中低凸起古构造演化与变形特征

通过区域地质和构造地震精细研究,提出了塔里木南缘早古生代板块构造控制塔南—塔中从伸展到挤压盆地演化：寒武纪—早奥陶世板缘拉张控制了塔中北斜坡断陷构造;中奥陶世北昆仑洋盆关闭后塔中前缘隆起;晚奥陶世—晚泥盆世塔中前陆冲断与走滑构造变形。晚奥陶世塔南前陆冲断构造由东南向西北方向传播,形成塘北—塔中南—塔中5号断裂带等弧形断裂体系和塔中低凸起中西段与Ⅰ号断裂带小角度斜交的走滑断裂体系。冲断构造位移的传播受控于两个滑脱层：其一是沿寒武系内部膏盐岩的滑脱,形成弧形冲断构造,终止于塔中南缘断裂带;另一个是沿中地壳韧性变形带的滑脱,形成塔中1号断裂带东端的弧形构造带。塔中1号断裂带东段的构造变形方式主要为向北传播水平位移的断层传播褶皱和向南反向冲断的楔形构造。塔中低凸起的中西段右行走滑构造导致了向东收敛的扫帚状走滑断裂体系的形成,剖面发育花状构造。塔中低凸起的古构造演化与变形特征、构造变形样式、构造变形成因和断裂体系,是克拉通盆地内部叠合盆地深层的主要构造地质特征。     

Convergence History of the Songliao and Jiamusi Blocks in the Eastern End of Central Asian Orogenic Belt: Evidence from Detrital Zircons of Late Paleozoic Sedimentary Rocks

Central Asian Orogenic Belt(CAOB) is one of the largest accretionary orogenic belts in the world. The eastern segment of CAOB is dominated by Paleozoic Paleo Asian Ocean tectonic regime, Mesozoic Paleo-Pacific tectonic regime and Mongolian-Okhotsk tectonic regime. The Songliao and Jiamusi blocks are located in the easternmost part of the CAOB and are the key region to solve the problem about overprinting processes of multiple tectonic regimes. It is generally believed that the Mudanjiang Ocean between the two blocks was finally closed in the Mesozoic, but the Paleozoic magmatism also developed along the Mudanjiang suture zone, while on both sides of the suture zone, there were comparable Paleozoic strata, indicating that the two blocks had converged during the Paleozoic, and the evolution history of the two blocks in the Late Paleozoic remains controversial. The Carboniferous-Permian terrestrial strata mainly developed in Binxian, Wuchang and Tieli on Songliao Block, Baoqing and Mishan on Jiamusi Block. Samples from the Songliao and Jiamusi blocks in the Late Carboniferous-Early Permian and Late Permian are collected for comparative analysis. The LAICP-MS zircon U-Pb dating results show that the maximum depositional age of Middle Permian Tumenling Formation and Late Permian Hongshan Formation in Songliao Block is ～260 Ma, while that of Tatouhe Formation and Carboniferous strata in Jiamusi Block are ～290 Ma and ～300 Ma, respectively, which supports the previous stratigraphic division scheme. The age peaks of ～290–300 Ma, ～400 Ma, ～500 Ma appeared in the Late Carboniferous to Early Permian strata of Jiamusi Block and the Middle Permian strata of Songliao Block. The age peak of ～500 Ma in the Middle Permian strata of Songliao Block may come from the Cambrian basement, Mashan Complex, of Jiamusi Block, while the age peaks of ～420–440 Ma in the Carboniferous strata of Jiamusi Block may come from the Silurian magmatic arc in Zhangguangcai Range in the eastern margin of Songliao Block, reflects the history that they had been potential sources of each other, indicating that they may have combined in the Paleozoic. The Hongshan Formation of Songliao Block in the Late Permian lacks the age peak of ～500 Ma, which indicate that Jiamusi Block was not the provenance of Songliao Block in the Late Permian, that is, there was a palaeogeographic isolation between the two blocks. Combined with the ～210 Ma bimodal volcanic rocks developed along the Mudanjiang suture zone reported previously, we believe that the oceanic basin between the Songliao and Jiamusi blocks should have been connected in Late Permian and reopened during Late Permian to Late Triassic.     

内蒙古东七一山花岗岩地球化学、锆石SHRIMP U-Pb年龄及岩体形成环境探讨

古生代时期, 北山地区的地壳活动非常强烈, 主要表现为: 早古生代初期大陆的裂解, 一直到中奥陶世广阔大洋盆的发育。志留纪末, 洋盆在自南向北的俯冲中封闭, 使北侧的哈萨克斯坦板块和南侧的塔里木板块拼贴, 并在碰撞造山过程中又构成了一个相对统一的陆块。在晚古生代, 北山地区地壳又在另外一种形式中异常强烈活动, 特别是自石炭纪到二叠纪, 大规模的中酸性岩浆侵入活动构成本区重要的地质事件, 其出露的花岗岩类占到了全区总面积的近1/3, 但泥盆纪时期的地壳活动, 特别是花岗岩浆的侵入活动常被人们忽视, 笔者据泥盆纪时期的沉积-火山作用及挤压构造活动也较发育认为, 海西早期也应有较强的花岗岩浆侵入活动。本文有针对性地对北山地区, 原定为海西中期的东七一山花岗岩岩基, 在岩石学和地球化学等方面研究基础上, 对3处岩石中锆石首次进行了SHRIMP U-Pb年龄测定, 其结果分别是(355±4) Ma、 (359±4) Ma、(355±5) Ma, 这表明东七一山花岗岩形成于泥盆纪晚期, 从而确定了北山晚古生代早期也有花岗岩浆的强烈活动, 这对深化北山古生代地壳演化过程有积极意义。     

塔里木盆地玉东-玛东构造带断层相关褶皱样式及演化

玉东-玛东构造带位于塔里木盆地,是在中寒武统膏盐层上滑脱的大规模褶皱冲断带,内部发育多种断层相关褶皱。目前对此构造带的研究,多关注了构造带的局部以及断裂变形。本文根据断层相关褶皱理论,利用地震资料,分析了玉东-玛东构造带内构造样式上的差异性,并通过二维构造正演模拟,建立了典型构造样式的运动学模式。认为研究区内玉东、玛东、塘北3个分区,具有不同的构造样式。玉东地区主要发育和铲式逆断层相关的断弯褶皱,玛东、塘北地区则发育断层突破的滑脱褶皱,突破断层在玛东地区为铲式断裂,而在塘北地区为坪-坡-坪式断裂。根据上奥陶统变形特征及其顶面不整合面之上的地层年代,认为玉东-玛东构造带的变形始于晚奥陶世,主要断裂及其相关褶皱形成于晚奥陶世末期。玉东地区在晚奥陶世早期,形成基底-盖层的低幅褶皱,在晚奥陶世末,形成铲式断裂及断弯褶皱;玛东和塘北地区变形发生在上奥陶统沉积之后,经历了滑脱褶皱和断层突破阶段。通过对比分析认为,断层相关褶皱样式的差异,与膏盐层岩性、厚度,上奥陶统岩性、厚度及构造转换作用有关。本研究有助于完善对塔里木盆地早古生代末期构造变形及演化的认识。     

塔里木盆地早古生代构造古地理演化与烃源岩

塔里木陆块为一具前寒武系基底的克拉通盆地,早震旦世—寒武纪陆块内和边缘发生裂解,至中奥陶世转为被动大陆边缘,组建塔北和塔中两个遥相对应的碳酸盐台地和边缘斜坡,其间的阿瓦提—满加尔地区为克拉通内浅海—深水盆。满参1井以东至满加尔为欠补偿的深海槽盆,早期沉积了富生物营养链的烃源岩,晚奥陶世克拉通转为前陆碎屑岩沉积,满加尔坳陷反转为浊流盆地。碎屑岩由东向西、由南东向北西迁移,造成向塔北和塔中海侵上超,结束碳酸盐台地演化的同时,沉积了局限台地型和台缘斜坡灰泥丘相的烃源岩。奥陶纪时塔里木盆地演化和沉积相的配置,是加里东期盆山转换的重要反响,形成多个沉积-构造转换面。早加里东运动,造成下早奥陶统与寒武系的假整合;中加里东运动即晚奥陶世始,塔里木转为前陆盆地,塔北和塔中分别为前陆隆起,阿瓦提—满加尔为复合隆间盆地;晚加里东运动(始于早志留世)发生了大规模的海退。     

雪峰山隆起北缘热历史及其对牛蹄塘组生烃作用的影响

对于复杂构造带的古老- 深层页岩，烃类的生成过程可能是多阶段的。准确恢复页岩的成熟演化过程是研究页岩气富集机理的先决条件。本文依托雪峰山隆起北缘新钻探的地质调查井，恢复雪峰山北缘古生代以来的热历史，从热演化的角度讨论牛蹄塘组页岩的生烃潜力。元素分析显示，热液活动对牛蹄塘组黑色页岩有机质的富集产生了积极影响，特别是下部页岩热液指示指标异常高、显著的Ce负异常、Eu正异常和Y正异常，都证明了牛蹄塘组早期受热液作用的影响。古温标联合反演结果显示，雪峰山北缘自古生代以来先后经历了三次升温—降温过程。三次热演化高峰依次出现在晚奥陶世末期、中三叠世末期和早白垩世末期，所达到的最高温度依次降低。三次升温过程分别受到早古生代拉张作用和岩浆活动、晚古生代—早中生代快速沉降作用和早白垩世岩浆活动的控制。受沉积埋藏作用和早期热事件的影响，牛蹄塘组页岩在寒武纪—早志留世快速经历了生油高峰、原油裂解高峰等生烃关键时期，在晚奥陶世达到过成熟阶段。随后第一次的抬升剥蚀作用，破坏了页岩及上覆盖层的封闭性，形成有利于气体扩散的裂缝或断层通道，使得早期形成的烃类散失。     

关于古亚洲洋构造演化研究的几点思考

古亚洲洋不是西伯利亚陆台和华北地台间的一个简单洋盆,而是在不同时间、不同地区打开和封闭的多个大小不一的洋盆复杂活动(包括远距离运移)的综合体.其北部洋盆起始于新元古代末-寒武纪初(573~522Ma)冈瓦纳古陆裂解形成的寒武纪洋盆.寒武纪末-奥陶纪初(510~480Ma),冈瓦纳古陆裂解的碎块、寒武纪洋壳碎块和陆缘过渡壳碎块相互碰撞、联合形成原中亚-蒙古古陆.奥陶纪时,原中亚-蒙古古陆南边形成活动陆缘,志留纪形成稳定大陆.泥盆纪初原中亚-蒙古古陆裂解,裂解的碎块在新形成的泥盆纪洋内沿左旋断裂向北运动,于晚泥盆世末到达西伯利亚陆台南缘,重新联合形成现在的中亚-蒙古古陆.晚古生代时,在现在的中亚-蒙古古陆内发生晚石炭世(318~316Ma)和早二叠世(295~285Ma)裂谷岩浆活动,形成双峰式火山岩和碱性花岗岩类.蒙古-鄂霍次克带是西伯利亚古陆和中亚-蒙古古陆之间的泥盆纪洋盆,向东与古太平洋连通,洋盆发展到中晚侏罗世,与古太平洋同时结束,其洋壳移动到西伯利亚陆台边缘受阻而向陆台下俯冲,在陆台南缘形成广泛的陆缘岩浆岩带,从中泥盆世到晚侏罗世都非常活跃.古亚洲洋的南部洋盆始于晚寒武世.此时,华北古陆从冈瓦纳古陆裂解出来,在其北缘形成晚寒武世-早奥陶世的被动陆缘和中奥陶世-早志留世的沟弧盆系.志留纪腕足类生物群的分布表明,华北地台北缘洋盆与塔里木地台北缘、以及川西、云南、东澳大利亚有联系,而与上述的古亚洲洋北部洋盆没有关连,两洋盆之间有松嫩-图兰地块间隔.晚志留世-早泥盆世,华北地台北部发生弧-陆碰撞运动,泥盆纪时,在松嫩地块南缘形成陆缘火山岩带,晚二叠世-早三叠世华北地台与松嫩地块碰撞,至此古亚洲洋盆封闭.古亚洲洋的南、北洋盆最后的褶皱构造,以及与塔里木地台之间发生的直接关系,很可能是后期的构造运动所造成的.     

Tectonics and geodynamics of the western Central Asian Fold Belt (Kazakhstan Paleozoides)

On the basis of stratigraphical and geological data, paleogeographical and palinspastic reconstructions of the Kazakhstan Paleozoides were done; their multistage geodynamic evolution was considered; their tectonic zoning was proposed. The main stages are described: the initiation of the Cambrian and Ordovician island arcs; the development of the Kazakhstan accretionary–collisional composite continent in the Late Ordovician as a result of continental subduction and the amalgamation of Gondwana blocks with the island arcs (a long granitoid collisional belt also formed in this period); the development of the Devonian and Carboniferous–Permian active margins of the composite continent and its tectonic destruction in the Late Paleozoic.In the Late Ordovician, compensated terrigenous and volcanosedimentary complexes formed within Kazakhstania and developed in the Silurian. The Sakmarian, Tagil, Eastern Urals, and Stepnyak volcanic arcs formed at the boundaries with the Ural, Turkestan, and Junggar–Balkhash Oceans. In the late Silurian, Kazakhstania collided with the island arcs of the Turkestan and Ob'–Zaisan Oceans, with the formation of molasse and granite belts in the northern Tien Shan and Chingiz. This was followed by the development of the Devonian and Carboniferous–Permian active margins of the composite continent and the inland formation of the Early Devonian rift-related volcanosedimentary rocks, Middle–Late Devonian volcanic molasse, Late Devonian–Early Carboniferous rift-related volcanosedimentary rocks, terrigenous–carbonate shelf sediments, and carbonaceous lake–bog sediments, and the Middle–Late Carboniferous clastic rocks of closed basins. In the Permian, plume magmatism took place on the southern margin of the Kazakhstan composite continent. It was simultaneous with the formation of red-colored molasse and the tectonic destruction of the Kazakhstan Paleozoides as a result of a collision between the East European and Kazakhstan–Baikal continents.