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1.
In southern Poland, Miocene deposits have been recognised both in the Outer Carpathians and the Carpathian Foredeep (PCF). In the Outer Carpathians, the Early Miocene deposits represent the youngest part of the flysch sequence, while in the Polish Carpathian Foredeep they are developed on the basement platform. The inner foredeep (beneath the Carpathians) is composed of Early to Middle Miocene deposits, while the outer foredeep is filled up with the Middle Miocene (Badenian and Sarmatian) strata, up to 3,000mthick. The Early Miocene strata are mainly terrestrial in origin, whereas the Badenian and Sarmatian strata are marine. The Carpathian Foredeep developed as a peripheral foreland basin related to the moving Carpathian front. The main episodes of intensive subsidence in the PCF correspond to the period of progressive emplacement of the Western Carpathians onto the foreland plate. The important driving force of tectonic subsidence was the emplacement of the nappe load related to subduction roll-back. During that time the loading effect of the thickening of the Carpathian accretionary wedge on the foreland plate increased and was followed by progressive acceleration of total subsidence. The mean rate of the Carpathian overthrusting, and north to north-east migration of the axes of depocentres reached 12 mm/yr at that time. During the Late Badenian-Sarmatian, the rate of advance of the Carpathian accretionary wedge was lower than that of pinch-out migration and, as a result, the basin widened. The Miocene convergence of the Carpathian wedge resulted in the migration of depocentres and onlap of successively younger deposits onto the foreland plate.  相似文献   

2.
中生代羌塘前陆盆地充填序列及演化过程   总被引:40,自引:1,他引:40  
李勇  王成善  伊海生 《地层学杂志》2002,26(1):62-67,79
中生代羌塘前陆盆地位于青藏高原巨型造山带内 ,夹于金沙江缝合带与班公湖—怒江缝合带之间 ,是一个与两侧缝合带逆冲作用相关的沉积盆地 ,由羌北盆地 (对应于金沙江缝合带 )、羌南盆地 (对应于班公湖—怒江缝合带 )和中央隆起带构成 ,其中中央隆起是北部前陆盆地和南部前陆盆地共有的前陆隆起 ,显示为对称型复合前陆盆地 ;该盆地形成于晚三叠世 ,并持续发育至早白垩世 ,盆地中充填了巨厚的同构造期的复理石和磨拉石 ,具有总体向上变粗变浅的充填序列 ,以不整合面可将其划分为 5个由顶底不整合面限制的构造层序 ,其中晚三叠世诺利期构造层序对应于金沙江缝合带主碰撞期 ,晚三叠世瑞替期构造层序对应于金沙江缝合带碰撞闭合后冲断抬升 ,早侏罗世构造层序对应于班公湖—怒江缝合带初始逆冲推覆 ,中侏罗世—早白垩世构造层序对应于班公湖—怒江缝合带主碰撞期 ,中白垩世构造层序为班公湖—怒江缝合带碰撞闭合后冲断抬升与金沙江缝合带冲断抬升的产物 ,为中生代羌塘盆地关闭后的磨拉石建造  相似文献   

3.
楚雄中生代前陆盆地的构造沉降史研究   总被引:14,自引:1,他引:13       下载免费PDF全文
云南楚雄盆地位于场子陆块的西南边缘,为一典型的中生代周缘前陆盆地,盆地演化阶段明显,晚三叠世为前陆早期复理石沉积,侏罗纪则为前陆晚期磨拉石沉积。对盆地构造沉降史研究后笔者认为:①晚三叠世复理石沉积盆地构造沉降幅度巨大,沉降与沉积中心位于盆地最西部,紧邻古哀牢山造山带,沉积体呈形楔形展布;③侏罗纪磨拉石沉积盆地构造沉降和沉积中心以及前缘隆起向内陆方向迁移明显;③中生代构造快速沉降的沉积体的楔形展布表  相似文献   

4.
《Geodinamica Acta》2013,26(1-3):101-126
The olistostromes formed in Northern Carpathians during the different stages of the development of flysch basins, from rift trough post-rift, orogenic to postorogenic stage. They are known from the Cretaceous, Paleocene, Eocene, Oligocene and Early Miocene flysch deposits of main tectonic units. Those units are the Skole, Subsilesian, Silesian, Dukla and Magura nappes as well as the Pieniny Klippen Belt suture zone. The oldest olistoliths in the Northern Carpathians represent the Late Jurassic-Early Cretaceous rifting and post-rifting stage of the Northern Carpathians and origin of the proto-Silesian basin. They are known from the Upper Jurassic as well as Upper Jurassic-Lower Cretaceous formations. In the southern part of the Polish Northern Carpathians as well as in the adjacent part of Slovakia, the olistoliths are known in the Cretaceous- Paleocene flysch deposits of the Pieniny Klippen Belt Zlatne Unit and in Magura Nappe marking the second stage of the plate tectonic evolution - an early stage of the development of the accretionary prism. The most spectacular olistostromes have been found in the vicinity of Haligovce village in the Pieniny Klippen Belt and in Jaworki village in the border zone between the Magura Nappe and the Pieniny Klippen Belt. Olistoliths that originated during the second stage of the plate tectonic evolution occur also in the northern part of the Polish Carpathians, in the various Upper Cretaceous-Early Miocene flysch deposits within the Magura, Fore-Magura, Dukla, Silesian and Subsilesian nappes. The Fore-Magura and Silesian ridges were destroyed totally and are only interpreted from olistoliths and exotic pebbles in the Outer Carpathian flysch. Their destruction is related to the advance of the accretionary prism. This prism has obliquely overridden the ridges leading to the origin of the Menilite-Krosno basin.

In the final, postcollisional stage of the Northern Carpathian plate tectonic development, some olistoliths were deposited within the late Early Miocene molasse. These are known mainly from the subsurface sequences reached by numerous bore-holes in the western part of the Polish Carpathians as well as from outcrops in Poland and the Czech Republic.

The largest olistoliths (kilometers in size bodies of shallow-water rocks of Late Jurassic-Early Cretaceous age) are known from the Moravia region. The largest olistoliths in Poland were found in the vicinity of Andrychów and are known as Andrychów Klippen. The olistostromes bear witness to the processes of the destruction of the Northern Carpathian ridges. The ridge basement rocks, their Mesozoic platform cover, Paleogene deposits of the slope as well as older Cretaceous flysch deposits partly folded and thrust within the prism slid northward toward the basin, forming the olistostromes.  相似文献   

5.
循化-化隆盆地新生代沉积及盆地基底和周缘山系磷灰石裂变径迹年代学分析揭示了青藏高原东北缘晚白垩世以来经历过3期隆升剥露事件: (1)盆地基底及拉脊山和西秦岭北缘构造带磷灰石裂变径迹年龄分析普遍记录了晚白垩世-始新世中期相对快速的区域性的隆升剥露事件, 西秦岭北缘快速抬升的起始时间为84Ma, 受控于向北的逆冲抬升; 向北到循化-化隆盆地中部的拉目峡抬升的起始时间为69Ma; 更北的拉脊山一带快速抬升期主要为40~50Ma, 从而反映晚白垩世-始新世中期的快速抬升由南向北逐渐扩展.这一期构造隆升事件导致循化-化隆盆地和临夏盆地缺失了北部西宁-民和盆地古近纪所具有的西宁群沉积.隆升剥露结束于31Ma左右, 此时化隆-循化盆地向东与同时期的临夏盆地相连为一个统一的大型西秦岭山前盆地, 两者具有相同的构造、沉积演化史, 因此循化-化隆盆地他拉组底部地层年龄最老不会超过临夏盆地最老地层的古地磁年龄, 即29Ma.(2)渐新世晚期约26Ma拉脊山开始双向逆冲隆升, 并可能延续到中新世早期约21Ma, 隆升作用使循化-化隆盆地成为挟持于拉脊山逆冲带和西秦岭构造带之间的山前挤压型前陆盆地, 循化-化隆盆地开始大规模沉积巨厚的他拉组冲积扇相粗碎屑岩.(3)通过循化-化隆盆地咸水河组和临夏组的沉积相分析、古流方向和砾石成分分析, 揭示出拉脊山构造带在中新世8Ma左右发生的最大规模的双向逆冲隆升事件, 这次事件直接导致循化-化隆盆地由前陆挤压盆地转变为山间盆地, 形成现今青藏高原东北缘的盆山地貌基本格局.   相似文献   

6.
川西前陆盆地中—新生代沉积迁移与构造转换   总被引:10,自引:0,他引:10       下载免费PDF全文
川西前陆盆地中—新生代各构造层的残余厚度展布和沉积特征分析发现,四川克拉通周缘的前陆盆地在晚三叠世时期发育于龙门山山前,明显属于龙门山褶皱逆冲构造载荷所形成的前渊凹陷;侏罗纪早期的沉积地层呈面状分布,没有表现出显著的挠曲沉降,指示了一个构造相对平静的阶段;中侏罗世早期前渊凹陷迁移至龙门山北段和米仓山山前,前渊沉积从晚三叠世的北东向转换为近东西向,广泛的湖泊相沉积预示了前陆盆地的欠充填状态;中侏罗世中晚期,川西盆地沉降中心又迁移到大巴山山前,相应的挠曲变形又从近东西向转化为北西向,构成了大巴山的前渊凹陷;晚侏罗世—早白垩世时期,沉降中心再次回到米仓山山前,巨厚的前渊凹陷沉积指示了米仓山冲断带的主要活动时期;白垩纪末—古近纪的前渊凹陷则跃迁至雅安—名山地区。川西前陆盆地的同造山沉降中心以四川盆地中心为核心在西部和北部呈弧形迁移,沉积序列不断更替和叠加。中生界各构造层底界构造图显示现今的构造低部位位于川西北地区和川西南地区,在川西北地区均有东西走向的等值线分布,而川西南地区等值线走向则为北东-南西向。因此分析认为,晚侏罗世至早白垩世的构造变形可能控制了川西盆地现今的地层变形,形成了川西北地区的南北向构造挤压结构,而晚期的新生代构造变形则主要体现在川西盆地的西南部,形成北东-南西向的地层展布特征。  相似文献   

7.
位于印度板块北缘和雅鲁藏布江结合带之间的珠穆朗玛峰北坡地区,属于喜马拉雅造山带,是特提斯洋的重要组成部分。自奥陶纪至古近纪约5亿年期间发育一套基本连续的海相沉积,厚度达14 km,是研究特提斯洋形成演化的最佳地区。作者在对该区显生宙地层主干剖面和辅助剖面详细观察研究以及区域地质调查填图的基础上,将珠穆朗玛峰北坡地区显生宙沉积地层划分为海相、海陆过渡相和陆相3个沉积相组、15个沉积相和若干个沉积亚相。作者通过对该区沉积盆地的地层系统、沉积相、沉积特征的系统研究,将珠穆朗玛峰北坡地区显生宙沉积演化划分为6个阶段:1)奥陶纪-泥盆纪为稳定陆表海演化阶段;2)石炭纪-二叠纪为大陆裂谷盆地演化阶段;3)三叠纪-侏罗纪为被动大陆边缘盆地演化阶段;4)早中白垩世为前陆早期复理石盆地演化阶段;5)晚白垩世-古新世为前陆晚期磨拉石盆地演化阶段;6)古近纪-第四纪为造山隆升断陷盆地形成演化阶段。研究结果表明,珠穆朗玛峰北坡地区显生宙沉积盆地经历了由陆表海盆地-大陆裂谷盆地-被动大陆边缘盆地-前陆盆地-断陷盆地的演化过程。  相似文献   

8.
扬子北缘晚造山阶段(即晚侏罗世—晚白垩世)发育以弧形构造为特征的前陆薄皮逆冲—褶皱构造,包括了沿秦岭—大别造山带发育的北西向的大洪山和大巴山弧形带,以及沿江南—雪峰造山带发育的北东向的川东—湘鄂西弧形带。详细的构造解析、盆地沉积及物源特征综合分析表明,弧形构造不仅将早期的前陆序列卷入变形,并且控制了晚侏罗世—晚白垩世的盆地演化和古地理格局。总结扬子北缘晚造山阶段的盆山演化特征,可以将其划分为3个阶段:(1)晚侏罗世—早白垩世早期,大洪山和大巴山弧形带的发育控制了四川盆地东北部及秭归盆地上侏罗统蓬莱镇组的沉积,川东—湘鄂西弧形带限制了盆地的东南边界,加之位于四川盆地西部的龙门山逆冲带,三面围限构成具前渊沉降的克拉通内盆地或称为“墙围盆地”(walled sedimentary basin);(2)早白垩世中期—早白垩世晚期,大洪山和大巴山弧形带的逆冲构造变形逐渐减弱,而川东—湘鄂西弧形带继续向北西扩展,构造线呈北东向展布,在弧形带前缘的宜昌地区形成沉积中心,并覆盖了现今的黄陵背斜;(3)晚白垩世,川东—湘鄂西弧形带继续向北西推进,构造线呈北北东向展布,弧形带北翼的黄陵背斜初始隆起,沉积中心分别位于北翼宜昌地区及南翼习水地区。与此同时,在弧形带内部薄皮构造的向斜部位形成楔顶沉积,发育如恩施盆地、黔江盆地、来凤盆地等一系列规模较小的背驼式盆地。  相似文献   

9.
青藏高原东缘新生代构造层序与构造事件   总被引:28,自引:7,他引:28       下载免费PDF全文
新生代龙门山前盆地和盐源盆地是青藏高原东缘龙门山-锦屏山冲断带内及前缘地区发育和保存最好的新生代沉积盆地,本次以地层不整合面和ESR测年资料为主要依据,将该区新生代构造地层序列划分为5个构造层序,即TS1(65-55Ma)、TS2(40-50Ma)、TS3(23-16Ma)、TS4(4.7-1.6Ma)和TS5(0.74-0Ma),据此将青藏高原东缘新生代构造变形和隆升事件划分为5期,其中TS1与喜马拉雅地体和拉萨地体拼合事件相关,TS2与印亚碰撞事件相关,TS3与青藏高原第一次隆升事件相关,TS4与青藏高原第二次隆升事件相关,TS5与青藏高原第三次隆升事件相关。  相似文献   

10.
通过对羌塘盆地南北两侧构造带地质特征、构造演化历程及盆地内部中生代地层充填特征的分析,探讨了羌塘盆地中生代构造属性及地球动力学机制。研究表明:羌塘盆地经历了早、中三叠世前陆盆地,晚三叠世早、中期被动陆缘盆地,晚三叠世晚期—侏罗纪羌北前陆盆地和羌南陆被动陆缘裂陷—坳陷盆地及早白垩世前陆盆地等地质演化历程;盆地南北边界构造带复杂而有序的地球动力学环境和构造演化,决定了羌塘盆地中生代为一复杂的多旋回叠合盆地。  相似文献   

11.
The late-Palaeozoic to Cenozoic stratigraphic and structural record of the southwestern margin of the Bohemian massif and its extension beneath the southward adjacent Molasse basin shows that it is controlled by a system of basement-involving faults which came into evidence during Stephanian– Autunian times and which were subsequently repeatedly reactivated. Thick Permo-Carboniferous clastics accumulated in fault-bounded transtensional basins aligned with the southwestern Bohemian border zone (SWBBZ). Following late-Autunian deformation of these basins, the SWBBZ was overstepped by late-Permian to Late Jurassic platform sediments, reflecting tectonic stability. During the Early Cretaceous the SWBBZ was strongly reactivated, causing disruption and erosion of its Mesozoic sedimentary cover. Sedimentation resumed in the area of the SWBBZ during late Early and Late Cretaceous with clastic influx from the Bohemian massif reflecting gradually increasing tectonic activity along the SWBBZ. During the Late Senonian and Paleocene transpressional deformations resulted in upthrusting of major basement blocks. In the Molasse basin such structures are sealed by transgressive Late Eocene marine strata. Mio-Pliocene uplift of the Bohemian massif, involving mild reactivation of the SWBBZ, is related to the development of the volcano-tectonic Eger zone. The structural configuration of the SWBBZ is largely the result of Late Senonian–Paleocene compressional intraplate tectonics which play a major role in the structural framework of the northern Alpine and Carpathian foreland.  相似文献   

12.
全球性的构造运动末期一般伴着海退和干旱的气候环境,而蒸发岩沉积与大地构造条件紧密相关。中亚卡拉库姆盆地、阿富汗_塔吉克盆地、塔里木盆地自晚侏罗世至中新世以来至少发生了3次大规模海侵_海退旋回,每次海侵_海退均受特提斯构造事件控制。卡拉库姆盆地、阿富汗_塔吉克盆地为晚侏罗世—早白垩世蒸发岩沉积、塔里木盆地的莎车次级盆地为晚白垩世—古新世蒸发岩沉积,库车次级盆地为古新世—中新世蒸发岩沉积,形成特提斯构造域自西向东蒸发岩沉积时代逐渐变新的盐湖链。中亚及塔里木盐湖链在海侵_海退旋回的控制下,至少发生5次大规模的蒸发岩沉积,发育2种不同的蒸发岩沉积序列,分别对应3次海退期蒸发岩沉积序列及2次断续海侵期蒸发岩沉积序列,具体为晚侏罗世晚期(海退期)卡拉库姆盆地、阿富汗_塔吉克盆地蒸发岩沉积;早白垩世—晚白垩世早期(断续海侵期)阿富汗_塔吉克盆地蒸发岩沉积;晚白垩世晚期(海退期)莎车次级盆地蒸发岩沉积;古新世—中新世(断续海侵期)莎车次级盆地、库车次级盆地蒸发岩沉积;中新世晚期—上新世早期(海退期)库车次级盆地蒸发岩沉积。塔里木与中亚古盐湖发育受控于特提斯构造事件及海侵_海退旋回,而海侵_海退旋回又控制2种不同的蒸发岩沉积序列。蒸发岩沉积序列、古盐湖演化阶段、蒸发岩物质来源、沉积环境决定了盐类矿物沉积类型(单一化学岩型、陆缘碎屑岩_化学岩型),卡拉库姆盆地、阿富汗_塔吉克盆地盐类矿物与塔里木盆地相比,种类简单,反映了盆地化学岩与陆源碎屑_化学岩沉积的区别及后期构造运动对盐类矿物种类的主控作用。  相似文献   

13.
造山带和盆地是在时空发展和形成机制上具有密切联系的构造系统。青藏高原内部晚三叠世古特提斯造山带的形成,对北缘的塔里木盆地产生了重要的影响,导致了盆地内部西昆仑山前地区发生了强烈的冲断构造变形,而这一冲断构造变形所形成的古构造-古地貌对后期侏罗-白垩纪的沉积具有重要的控制作用,同时也决定了该地区的油气分布。本文基于对西昆仑山前露头区中生代地层分布详细的野外考察和盆地覆盖区钻井资料的整理,结合对盆-山结合带清晰地震剖面的详细解释,开展西昆仑山前的晚三叠世古构造特征及侏罗-白垩纪沉积充填过程研究,以期揭示晚三叠世的古构造-古地貌特征及对沉积的控制作用。通过研究发现,西昆仑山前地区发育晚三叠世前陆褶皱冲断带,冲断带根部发育基底卷入构造,锋带发育叠瓦状构造;古生界受逆冲断裂控制,形成一系列的北陡南缓的背斜隆起,冲断带前锋位置与新生代构造前锋位置相近。三叠纪末古地貌形态由于特提斯造山带的强烈隆升,总体呈南高北低的地貌形态,但是褶皱冲断构造带受地表风化剥蚀作用,背斜核部形成南缓北陡的古隆起,而断层破碎带形成南陡北缓的洼地,是侏罗系发育前的基本地貌格架。早侏罗世受特提斯造山带造山后伸展的影响,西昆仑山前发育4个箕状断陷,控陷断层发育于古造山带一侧;受大型控陷断层的影响,在断陷内部呈北高南低的地形特点,断陷内侏罗系逐渐向北部斜坡超覆。晚三叠世形成的古构造-古地貌与早侏罗世断陷叠加形成的古地理格架一直控制了侏罗纪-早白垩世的沉积,直到晚白垩世沉积时才没有起到控制作用。  相似文献   

14.
赵珍  吴珍汉  于俊秋  吴艳君 《地质学报》2019,93(8):1849-1866
尼玛—荣玛地区位于羌塘盆地中段,发育大量的逆冲推覆构造体系。尼玛以北主要发育自北向南运动的逆冲推覆构造体系,导致中央隆起带和班公—怒江构造带的岩石地层组合、三叠系和侏罗系地层逆冲在红层之上,其中北羌塘盆地侏罗系地层越过中央隆起,在南羌塘盆地发育滑脱构造并形成薄皮逆冲推覆构造及大型逆冲岩席;尼玛以南主要发育自南向北运动的逆冲推覆构造体系,造成侏罗—白垩系、白垩系岩石组合逆冲在红层之上。逆冲推覆构造普遍控制了红层盆地的生长,并被中新世湖相沉积角度不整合覆盖。逆冲推覆构造活动时代为早白垩世晚期至古近纪,其中中央隆起和班公—怒江构造带最早经历了早白垩世晚期—晚白垩世的抬升,随后整个研究区经历了古近纪的构造抬升,分别与新特提斯洋板片的北向俯冲以及印度—拉萨地块陆陆碰撞存在动力学相关;中新世以来的东西向伸展构造则导致局部差异抬升。逆冲推覆构造破坏了早期油气成藏,但同时伴生的断褶系统也促进地层增厚和有机质成熟,为二次生烃提供了有利的构造圈闭条件,桑列勒以及尼玛一带背斜圈闭是有利的油气靶区。  相似文献   

15.
Cenozoic sedimentary deposits in central-southern Ningxia province, NW China are an important record of Tertiary tectonic events along the evolving Qinghai–Tibetan Plateau’s northeast margin. Shortly after the onset of the Indo-Eurasia collision to the south, a thrust belt and adjoining foreland basin began to form during 40–30 Ma. The Eocene Sikouzi Formation developed in a distal setting to this basin, in normal fault-bound basins that may have formed in a forebulge setting. Subsequent deposition of the Oligocene Qingshuiying Formation occurred during a phase of apparently less intense tectonism and the previous underfilled foreland basin became overfilled. During the Early Miocene, contractional deformation was mainly distributed to the west of the Liupan Shan. This resulted in deformation of the Qingshuiying Formation as indicated by an unconformity with the overlying Miocene Hongliugou Formation. The unconformity occurs proximal to the Haiyuan Fault suggesting that the Haiyuan Fault may have begun movement in the Early Miocene. In the Late Miocene, thrusting occurred west of the southern Helan Shan and an unconformity developed between the Hongliugou and Qingshuiying Formations proximal to the the Cha-Gu Fault. Relationships between the Miocene stratigraphy and major faults in the region imply that during the Late Miocene the deformation front of the Qinghai–Tibetan Plateau had migrated to the Cha-Gu Fault along the western Ordos Margin, and the Xiang Shan was uplifted. Central-southern Ningxia was then incorporated into the northeast propagating thrust wedge. The driving force for NE propagation of the thrust wedge was most likely pronounced uplift of the northeastern plateau at the same time. Analysis of the sedimentary record coupled with consideration of the topographic evolution of the region suggests that the evolving fold-and-thrust belt experienced both forward-breaking fold-and-thrust belt development, and out-of-sequence fault displacements as the thrust wedge evolved and the foreland basin became compartmentalised. The documented sedimentary facies and structural relationship also place constraints on the Miocene-Recent evolution of the Yellow River and its tributaries.  相似文献   

16.
江汉盆地当阳向斜区主要不整合面剥蚀厚度   总被引:1,自引:0,他引:1  
施小斌  石红才  杨小秋 《地质学报》2013,87(8):1076-1088
本文利用磷灰石裂变径迹、(U-Th Sm)/He及镜质体反射率Ro%等古温标方法综合分析了江汉盆地当阳向斜区主要不整合面剥蚀厚度.结果表明:发育于古近纪末期不整合面T1界面累积剥蚀厚度超过1000m,且局部正反转区域如谢家湾断褶带等则遭受更大规模的剥蚀,剥蚀厚度可能超过2000m,而发育于晚侏罗世一早白垩世的不整合面T11界面累积剥蚀厚度超过4000m,且主要是晚侏罗世早白垩世构造事件的结果,表明该期剥蚀量明显大于古近纪末T1界面剥蚀量;晚三叠世—侏罗纪期间,当阳地区发育前陆坳陷带,侏罗纪堆积体具有明显东厚西薄的楔形体特征,位于盆地东部的前渊区沉积厚度可超过5000m;包括现今三叠系和侏罗系出露区以及江陵凹陷局部断隆区在内的前白垩系在侏罗纪前陆坳陷带发育时期达到最大埋深和最高古温度,其Ro%主要是该期获得的;晚白垩世—古近纪发育的断陷盆地范围可能远比现今残留盆地分布广,江陵凹陷上白垩统—古近系厚度超过9000m,其中古近系可能超过7000m,而在河溶凹陷谢家湾断褶带古近系厚度可超过3300m.  相似文献   

17.
The Ordos basin was developed from Mid-Late Triassic to Early Cretaceous, and then entered into its later reformation period since the Late Cretaceous. Its main body bears the features of an intra-cratonic basin. The basin also belongs to a multi-superposed basin which has overlapped on the large-scale basins of the Early and Late Paleozoic. Currently, Ordos basin has become a residual basin experienced reformation of various styles since the Late Cretaceous. It's suggested that there were at least four obvious stages of tectonic deformations existing during the basin's evolution, dividing the evolution and sedimentation into four stages. The prior two stages were of the most prosperous, during which the lake basin was broad, the deposition range was more than twice larger than the current residual basin, resulting in major oil- and coal-bearing strata. The two stages were separated by regional uplift fluctuations in the area. At the end of the Yan'an Stage, the depositional interruption and erosion were lasting for a short period of time. The third one is the Mid- Jurassic Zhiluo-Anding stage, in which the sedimentation extent was still broad but the lake area was obviously reduced. In the Late Jurassic tectonic deformation was intensive. A thrust-nappe belt was formed on the basin's western margin while conglomerate of different thickness were accumulated within the foredeep of the eastern side. The central and eastern parts of the basin were subject to erosion and reformation. A regional framework with "uplift in the east and depression in the west" took shape in the area west of the Yellow River. In the Early Cretaceous sediments were widely distributed, unconformably overlapping the former western margin thrust belt and the ridges on the northern and southern borders. There are abundant energy resources such as oil, natural gas, coal and uranium deposits formed in Ordos Basin. The main stages of generation, mineralization and positioning of the multiple energy resources have obvious responding co  相似文献   

18.
准噶尔盆地西部油气资源丰富,油气分布受构造演化过程控制作用显著。本文根据地表露头、地震、钻井、同位素年代学资料对盆地西部多期构造演化进行了研究,发现现今的盆地结构是造山带与盆地的相互作用下多期成盆演化与构造叠加演变的结果。根据地层不整合接触关系与空间展布特征,将该区构造地层层序划分为石炭系、中下二叠统、上二叠统—三叠系、侏罗系、白垩系、新生界等6个构造地层层序。石炭纪末的构造事件为车排子、中拐凸起和玛湖、沙湾、四棵树凹陷的形成奠定了基础。早二叠世为伸展构造环境,形成玛湖、沙湾及四棵树3个沉降、沉积中心,盆地西部重要烃源岩形成。中二叠世形成坳陷型盆地,沉积、沉降中心由山前向盆地内迁移。中二叠世末构造运动导致了西部山前沉积地层反转与隆升剥蚀,断裂向盆地逆冲。晚二叠世—三叠纪大型坳陷盆地的沉积、沉降中心在沙湾凹陷,受车排子凸起北翼断裂控制,地层向北、西超覆沉积,相继将中拐凸起、玛湖凹陷及山前断裂带埋藏。三叠纪末的构造运动在乌-夏和车排子地区形成向盆地方向的逆冲构造带。前侏罗纪,造山带与盆地表现出不同方式、不同强度构造耦合作用。侏罗纪—白垩纪,西准噶尔的构造活动弱,湖盆地不断扩张,沉积地层不断向造山带方向超覆;沉积、沉降中心由西向东,再由东向西,最后向南迁移演化。新生代,北天山山前强烈拗陷,盆地整体南北向掀斜,形成新近纪前陆盆地。盆地的多期翘倾掀斜作用与后期沉积地层向造山带的超覆沉积作用控制了油气的聚集,被后期埋藏的冲断带成为油气富集带。  相似文献   

19.
The Dabie orogenic belt underwent deep subduc-tion of continent, rapid exhumation, and huge amount of erosion during the Mesozoic. Its tectonic evolution, especially how that was recorded in sedimentary ba-sins at the flanks of the Dabie orogenic belt is one of the most important issues. The overall distribution of different basin types in the orogenic belt indicates that shortening and thrusting at the margins of the orogenic belt from the Late Triassic to the Early Cretaceous controlled the foreland basins, and extension, doming and rifting were initiated in the core of the orogenic belt from the Jurassic to the Early Cretaceous, and were expanded to the whole orogenic belt after the Late Cretaceous.  相似文献   

20.
The southern Central Andes of Argentina and Chile (27–40°S) are the product of deformation, arc magmatism, and basin evolution above a long-lived subduction system. With sufficient timing and provenance constraints, Andean stratigraphic and structural records enable delineation of Mesozoic-Cenozoic variations in subsidence and tectonic regime. For the La Ramada Basin in the High Andes at ∼31–33°S, new assessments of provenance and depositional age provided by detrital zircon U-Pb geochronology help resolve deformational patterns and subsidence mechanisms over the past ∼200 Myr. Marine and nonmarine clastic deposits recorded the unroofing of basin margins and sediment contributions from the Andean magmatic arc during Late Triassic to Early Cretaceous extension, thermal subsidence, and possible slab rollback. Subsequent sediment delivery from the Coastal Cordillera corresponded with initial flexural accommodation in the La Ramada Basin during Andean shortening of late Early Cretaceous to Late Cretaceous age. The architecture of the foreland basin was influenced by the distribution of precursor extensional depocenters, suggesting that inherited basin geometries provided important controls on later flexural subsidence and basin evolution. Following latest Cretaceous to early Paleogene tectonic quiescence and a depositional hiatus, newly dated deposits in the western La Ramada Basin provide evidence for a late Paleogene episode of intra-arc and proximal retroarc extension (development of the Abanico Basin, principally in Chile, at ∼28–44°S). Inversion of this late Paleogene extensional basin system during Neogene compression indicates the southern Central Andes were produced by at least two punctuated episodes of shortening and uplift of Late Cretaceous and Neogene age.  相似文献   

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