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1.
西藏措勤盆地中侏罗世-早白垩世沉积充填特征 总被引：3，自引：0，他引：3
位于班公湖-怒江缝合带与雅鲁藏布江缝合带之间的措勤盆地,在中侏罗世-早白垩世期间具有以且坎-古昌-阿索裂谷带为沉积、沉降中心向南北两侧展开的古地理格局：①中晚侏罗世时期,裂谷带内由深水浊积岩、放射虫硅质岩和浅水碳酸盐岩、碎屑岩岩片及基性-超基性岩等组成;裂谷带两侧由滨浅海相碎屑岩和碳酸盐岩组成。该期盆地古地理演化具有先变深后变浅的沉积序列。②早白垩世早中期,裂谷带内仍由基性-超基性岩、深水复理石碎屑岩及放射虫硅质岩和浅水碳酸盐岩及碎屑岩组成;裂谷带两侧的日松-革吉-它日错分区主要由浅海相碎屑岩和灰岩组成;盆地南北部的措勤-申扎分区和木嘎岗日分区主要由滨岸．三角洲相碎屑岩及火山岩组成。各相带在纵向上均具有向上变深沉积序列。③早白垩世晚期,盆地以台地相碳酸盐岩沉积为主,裂谷带附近以发育台地边缘礁滩相沉积;裂谷带两侧的日松-革吉-它日错分区主要由开阔台地相灰岩组成;盆地南北部的措勤-申扎分区和木嘎岗日分区由局限台地相灰岩和陆源进积碎屑岩组成。 相似文献
2.
位于班公湖-怒江缝合带与雅鲁藏布江缝合带之间的措勤盆地,在中侏罗世-早白垩世期间具有以且坎-古昌-阿索裂谷带为沉积、沉降中心向南北两侧展开的古地理格局:①中晚侏罗世时期,裂谷带内由深水浊积岩、放射虫硅质岩和浅水碳酸盐岩、碎屑岩岩片及基性-超基性岩等组成;裂谷带两侧由滨浅海相碎屑岩和碳酸盐岩组成.该期盆地古地理演化具有先变深后变浅的沉积序列.②早白垩世早中期,裂谷带内仍由基性-超基性岩、深水复理石碎屑岩及放射虫硅质岩和浅水碳酸盐岩及碎屑岩组成;裂谷带两侧的日松-革吉-它日错分区主要由浅海相碎屑岩和灰岩组成;盆地南北部的措勤-申扎分区和木嘎岗日分区主要由滨岸-三角洲相碎屑岩及火山岩组成.各相带在纵向上均具有向上变深沉积序列.③早白垩世晚期,盆地以台地相碳酸盐岩沉积为主,裂谷带附近以发育台地边缘礁滩相沉积;裂谷带两侧的日松-革吉-它日错分区主要由开阔台地相灰岩组成;盆地南北部的措勤-申扎分区和木嘎岗日分区由局限台地相灰岩和陆源进积碎屑岩组成. 相似文献
3.
措勤盆地生物礁的分布有一定规律性,现今发现的8个生物礁剖面均分布于且坎-古昌-罗波-当穹错断裂两侧。结合该断裂带出现的放射虫硅质岩沉积和火山岩堆积,推测该断裂带不仅为控相断裂,而且曾经有深水沉积,由于后期的再次活动而消失于断裂带内部。断裂带两侧的生物礁应为台地边缘礁。 相似文献
4.
冈底斯弧弧后早白垩世裂谷作用的沉积学证据 总被引：9，自引：0，他引：9
冈底斯弧弧后地区早白垩世地层的一个显著特点是 ,由下而上普遍从陆相 -海陆交互相碎屑岩变化为海相碳酸盐岩。该地区在早白垩世中期开始了广泛的海侵 ,沉积范围由早期仅局限于班公湖 -怒江缝合带附近而扩展至羌塘地体南缘和拉萨地体 ,沉积了巨厚的台地相灰岩 ;与塔里木南部和思茅地区同期海平面变化非常不同 ,那里在晚白垩世才出现海侵。砂岩组分研究显示 ,早白垩世早期碎屑物源主要来自北侧的造山带 ,向上则逐步受到南侧火山弧的控制。在海侵层系的下部 ,发现了丰富的双峰型火山岩和双峰式火山岩碎屑。因而推断该区在早白垩世发生了强烈的裂谷沉降作用。与此同时的在印度和巴基斯坦境内的 L adakh- Kohistan弧后裂谷作用还形成了具有洋壳基底的Shyok边缘海。因此 ,在早中白垩世 ,欧亚大陆南缘为西太平洋型的活动大陆边缘 ,因强烈的弧后裂谷作用产生了一系列边缘海盆地 ;在包括青藏高原南部在内的欧亚大陆南缘 ,既没有构造动力、也没有古地理和古地形证据支持在早白垩世末 ( 99Ma± )即出现强烈的抬升。 相似文献
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塔里木盆地北部坳陷震旦纪-奥陶纪大陆裂谷性质及其演化 总被引：2，自引：0，他引：2
塔里木盆地北部坳陷是在前震旦纪结晶基底之上发育起来的大陆裂谷盆地,始于早震旦世,结束于晚奥陶世.裂谷的轴部自西向东由阿瓦提凹陷、满加尔凹陷、英吉苏凹陷(包括库鲁克塔格南区)组成,向东延伸到罗布泊以东地区.裂谷轴部与地幔隆起带和高磁异常带相对应.裂谷东部主要以半深海-深海相的浊积岩、放射虫硅质岩和笔石页岩为特征,裂谷西部和翼部则以浅水盆地相和台地相的碳酸盐为特征.裂谷早期的火山岩主要分布于中东部的切谷内,具有双峰式火山岩的特征,玄武岩属低硅高钛富碱型.据区域动力学背景、沉积特征、沉降速率,将裂谷演化划分为幼年期,成年期和衰亡期3个阶段. 相似文献
7.
华南新元古代裂谷盆地演化 总被引：6，自引：0，他引：6
《矿物岩石》2001,21(3):135-145
沉积学研究表明,华南新元古代沉积盆地具典型裂谷盆地沉积演化特征.代表裂谷盆地早期形成阶段的成因相组合有冲洪积相组合、陆相(或海相)火山岩及火山碎屑岩相组合、滨浅海相沉积组合、淹没碳酸盐台地及欠补偿盆地黑色页岩相组合;而代表中、后期形成阶段的成因相组合有滨岸边缘相至深海相组合,冰期冰积岩相组合、碳酸盐岩及碳硅质细碎屑岩相组合.华南裂谷盆地岩相古地理演化经历了5个重要的时期,整体上反映了一个由陆变海、由地堑-地垒相间盆地变广海盆地、由浅海变深海、盆地由小变大的演化过程.裂谷盆地的形成经历了裂谷基的形成、地幔柱作用与裂谷体的形成、被动沉降(下拗)与裂谷盖的形成三个阶段.华南裂谷盆地的形成演化与Rodinia超大陆在新元古代时期的裂解作用密切相关,它是超大陆解体过程的一个重要组成部分. 相似文献
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安徽泾县-南陵地区二叠纪沉积相与沉积环境分析 总被引：1，自引：0，他引：1
安徽泾县—南陵地区二叠系较发育,主要由碳酸盐岩、硅质岩和碎屑岩组成。二叠系船山组为浅水碳酸盐台地相;栖霞组底部碎屑岩段是滨海沼泽相,臭灰岩段和上、下富硅质灰岩段是水体较深的斜坡中部相,中部灰岩段是浅水开阔碳酸盐台地相,而顶部灰岩段是缓斜坡上部相;孤峰组和大隆组是缺氧滞流环境下的深水盆地至盆地边缘相;武穴组是碳酸盐台地相,银屏组属于滨海潟湖相;龙潭组是一套海陆交互的三角洲相沉积,包括从三角洲前缘到三角洲平原两个亚相,而泾县昌桥龙潭组顶部发育的生物碎屑灰岩属于开阔碳酸盐台地相。纵观二叠纪有三次大的海侵和两次大的海退旋回,海侵时间分别是:栖霞早期、茅口早期和长兴早期,海退时间分别是:紫松—隆林期末和茅口期末,其中栖霞期还包含两个海侵海退的亚旋回。 相似文献
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塔东地区寒武—奥陶纪岩相古地理分析 总被引：1，自引：0，他引：1
通过钻井资料以及露头资料的详细分析,在塔东地区寒武系—奥陶系识别出盆地相、斜坡相、台地相。根据盆地相沉积特征把塔东地区盆地相分为碳酸盐岩盆地、混积盆地、页岩-硅岩盆地三种类型。碳酸盐岩盆地相岩石类型为碳酸盐岩,混积盆地岩石类型为碳酸盐岩与页岩及硅岩互层,页岩-硅岩盆地岩石类型为泥页岩以及硅质岩。台地区发育台地边缘灰泥丘相、台缘滩相、开阔台地相等。灰泥丘主要为藻凝块岩,滩相主要为颗粒灰岩。综合塔里木盆地寒武纪—奥陶纪沉积特征提出了塔东地区碳酸盐岩沉积综合模式,并指出由台地至盆地方向,盆地由碳酸盐岩盆地向混积盆地及页岩-硅岩盆地过渡。在单井分析、露头资料分析、地震剖面分析的基础上,分析了塔东地区寒武纪—奥陶纪古地理展布。 相似文献
11.
Bilelyeri Group, Antalya Complex: deposition on a Mesozoic passive continental margin, south-west Turkey 总被引：1，自引：0，他引：1
The Bilelyeri Group comprises complexly deformed Mesozoic sedimentary rocks of continental-margin affinities (Kumluca Zone). These are structurally intercalated between a coeval carbonate platform to the west (Bey Daǧlari Zone) and late Triassic ophiolitic rocks and sediments, interpreted as emplaced marginal oceanic crust, to the east (Gödene Zone). Four formations erected in the Bilelyeri Group record the later stages of continental rifting and the progressive development of part of a Mesozoic passive continental margin. The two late Triassic formations, the Telekta? Tepe and the Hatipalani Formations, are dominated by terrigenous clastic and calcareous clastic sediments, including large detached blocks of reef limestone. These rocks were laid down by mostly mass-flow and turbidity-flow into steep-sided rift depressions. Organic reefs were constructed in bordering shallow seas while terrigenous clastic sediment was shed from exposed basement horsts. Thick sequences of mafic lavas were extruded (Norian) in axial parts of the rift zones, followed by a regional change to deposition of pelagic Halobia-bearing limestone. This culminated in a major hiatus involving large-scale sliding of shallow-water limestones into deeper water. The Jurassic to early Cretaceous Dereköy Formation mostly consists of siltstones, radiolarian cherts and mudstones, intercalated with redeposited limestones and black shales. During this time parts of the margin were bordered by major offshore carbonate complexes constructed partly on basement fragments previously rifted off the parent continental areas. Black shales and reduced hemipelagic sediments were deposited in an elongate trough between the main platform and an offshore complex to the east. Some degree of margin reactivation in the early Cretaceous is indicated by renewed deposition of turbiditic sandstone and chloritic clays in some distal sequences. Strong relative enrichment of manganese in some horizons is attributed to offshore volcanic exhalations. Subsequent regional subsidence in the mid-to late Cretaceous is suggested by a switch to predominantly calcareous, pelagic sedimentation on the adjacent platform and the offshore massifs as well as on the Bilelyeri margin. Tectonic disruption of the platform edge during the late Cretaceous is implied by major redeposition of shallow-water shelf limestones in proximal Bilelyeri sequences. The Bilelyeri margin and the adjacent Gödene Zone were tectonically deformed in latest Cretaceous to early Tertiary time and were thrust over the adjacent Bey Daǧlari platform in the early Miocene. Viewed in an East Mediterranean perspective, the Bilelyeri sequences were part of a locally north-south trending segment of a regionally east-west margin to a substantial oceanic area further south. This segment apparently suffered significant strike-slip deformation both during its construction and its later emplacement. Instructive comparisons can be made with other areas of the East Mediterranean, especially south-west Cyprus. 相似文献
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目前关于思茅地块西缘大凹子组的形成时代仍有分歧.在思茅地块西缘大中河剖面采集了硅质岩、砂岩、凝灰岩和玄武岩,通过放射虫组合和锆石U-Pb年龄方法,厘定其地质时代,并结合区域资料恢复地层序列.通过详细剖面实测,发现该剖面由6个地层断片组成:第一、四断片以含放射虫硅质岩为特征,放射虫组合指示其时代为晚泥盆世至早石炭世早期;第二、五断片以火山碎屑岩、具有鲍玛序列沉积特征的火山碎屑沉积岩为主,锆石U-Pb同位素年龄指示其时代为志留纪中期至早泥盆世;第三、六断片以火山岩沉积为特征,锆石U-Pb同位素年龄指示其时代为志留纪早期.结合前人资料认为思茅地块西缘分布的海相火山岩、碎屑岩和含放射虫硅质岩地层层序代表了志留纪到早石炭世早期的岛弧火山-沉积地层序列. 相似文献
13.
Andrzej Pszczółkowski Ryszard Myczyński 《Journal of South American Earth Sciences》2010,29(2):225-253
In the Guaniguanico Mountains of western Cuba, the Late Jurassic–Early Cretaceous limestones occur in three stratigraphic successions, which have accumulated along the proto-Caribbean margin of North America. The Late Jurassic subsidence and shallow-water carbonate deposition of the Guaniguanico successions have no counterpart on the northeastern Maya block, but some distant similarities with the southeastern Gulf of Mexico may exist. Four facies types have been distinguished in the Tithonian–Lower Valanginian deposits of the Guaniguanico tectonic units. Drowning of the Late Jurassic carbonate bank of the Sierra de los Organos occurred at the Kimmeridgian/Tithonian boundary. During this boundary interval, sedimentation in the west Cuban area and southwestern margin of the Maya block (Mexico) has evolved in a similar way in response to a major second-order transgression.The Lower Tithonian ammonite assemblages of the Guaniguanico successions indicate, in general, the neritic zone. Presence of juvenile gastropods and lack of adult specimens suggest unfavorable environment for these molluscs, probably related to low oxygenation levels. The Early Tithonian transgressive phase terminated about the lower boundary of the Chitinoidella Zone. The Late Tithonian “regressive” phase is weakly marked, whereas the latest Tithonian–earliest Berriasian strata were deposited during a deepening phase. The latter transgressive phase has ended in the Late Berriasian Oblonga Subzone. We correlate the bioturbated pelagic biomicrites of the Tumbitas Member of the Guasasa Formation with a significant fall of the sea level during the latest Berriasian–Early Valanginian. The average sedimentation rate for the Tumbitas Member biomicrites was about three times faster than for the Berriasian Tumbadero Member limestones. Sedimentation rates for the Tumbitas Member and the Valanginian limestones at the DSDP Site 535 in the southeastern Gulf of Mexico were similar. In the Los Organos succession, the Late Valanginian transgressive interval is associated with radiolarian limestones and black chert interbeds in the lower part of the Pons Formation. In the Southern Rosario succession, the pelagic limestones pass into the radiolarian cherts of the Santa Teresa Formation indicating a proximity of CCD during Late Valanginian–Hauterivian times. 相似文献
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N. Yu. Bragin 《Stratigraphy and Geological Correlation》2018,26(3):333-343
The assemblages of the Early Jurassic (Hettangian–Pliensbachian) and Late Jurassic–Early Cretaceous (Tithonian–Berriasian) radiolarians were described for the first time in the eastern part of the Ekonai Zone of the Koryak Highland. The Hettangian–Pliensbachian assemblage was found in siliceous rocks of the Ionai Nappe and this finding expands the stratigraphic interval of its siliceous sequences from the Carboniferous to the Early Jurassic. The Tithonian–Berriasian assemblage was found in volcanosiliceous rocks of the Yanranai accretionary complex. Both assemblages contain taxa abundant in the Tethyan regions. 相似文献
15.
S. V. Rud’ko 《Lithology and Mineral Resources》2018,53(4):307-323
The paper presents results of the lithological study of Upper Jurassic limestones, flyschoids and limestone breccias on the southern side of the Baidar Valley in the Crimean Mountains. Study of the microfacies revealed that the limestones are represented by deposits on lagoons, platform edge shoals, reefs, and forereef aprons on the carbonate platform slope. Flyschoids include deposits in the distributive turbidite channels and hemipelagic sediments in the deep-water part of the basin. Limestone breccias were formed by gravitation flows on the carbonate platform toe-of-slope and slope. The presence of gravitation deposits in the Upper Jurassic carbonate complexes of the Crimean Mountains can testify to the primary clinoform structure of this sedimentary sequence. Comparison of the obtained sedimentological data made it possible to reconstruct the facies model of the Crimean carbonate platform and main episodes of its formation. Development of the carbonate shelf was related to two transgressive-regressive cycles. A dome-shaped reef was formed away from the coast at the initial (Oxfordian) stage. The carbonate platform was formed at the early Kimmeridgian lowstand stage when sediments were deposited in the internal part of the platform adjacent to land. In the late Kimmeridgian and early Tithonian, configuration of the carbonate platform profile resembled a distally steepened ramp, and its active progradation and shelf expansion took place in the course of transgression. Regression in the late Tithonian–early Berriasian led to regressive transformation of the ramp into platform with a flattened shallow-water shelf. Tectonic deformations at the Jurassic/Cretaceous transition promoted the formation of megabreccias on the carbonate platform foreslope. The tectonically reworked rock sequence of the “extinct” carbonate platform was overlapped transgressively by the upper Berriasian or lower Valanginian, relatively deep-water deposits of the Cretaceous platform cover. 相似文献
16.
Studies of multichannel seismic reflection profiles, calibrated with borehole data, have been carried out in the Tunisian shelf surrounding the islands of Lampione and Lampedusa, in order to define the Mesozoic-Cenozoic stratigraphie and structural evolution of this sector of the Pelagian foreland. The stratigraphy and subsidence history show a subsiding Upper Jurassic carbonate platform buried, by syn- and post-rift neritic to deep marine siliciclastics, marls and limestones of Neocomian-early Eocene age. Thick Middle-Upper Eocene shallow-water carbonates (Halk el Menzel Fm.), lie unconformably over the deep-water sediments and exhibit progradational geometries.
Messinian evaporites are confined to the deepest parts of the Neogene basins and Plio-Quaternary sediments are widespread over the area. Several unconformities affect the stratigraphic column and have been interpreted as related to compressive events during Late Cretaceous-early Tertiary times. These compressive events produced uplift, folding and reverse faulting, trending about NW-SE and partly reactivating Lower Cretaceous extensional structures. The uppermost regional unconformity indicates widespread emergence and erosion during Oligocene and Miocene tintes and was probably related to a younger compressional phase. A strong Upper Miocene-Quaternary extension event also affected the area, characterized by WNW-ESE trending normal faults, parallel to faults flanking the main grabens of the Sicily Strait rift zone. Since the Messinian, the structural evolution of the area has been controlled by rift-related processes which triggered crustal extension in the Pelagian foreland. 相似文献
Messinian evaporites are confined to the deepest parts of the Neogene basins and Plio-Quaternary sediments are widespread over the area. Several unconformities affect the stratigraphic column and have been interpreted as related to compressive events during Late Cretaceous-early Tertiary times. These compressive events produced uplift, folding and reverse faulting, trending about NW-SE and partly reactivating Lower Cretaceous extensional structures. The uppermost regional unconformity indicates widespread emergence and erosion during Oligocene and Miocene tintes and was probably related to a younger compressional phase. A strong Upper Miocene-Quaternary extension event also affected the area, characterized by WNW-ESE trending normal faults, parallel to faults flanking the main grabens of the Sicily Strait rift zone. Since the Messinian, the structural evolution of the area has been controlled by rift-related processes which triggered crustal extension in the Pelagian foreland. 相似文献
17.
渭北奥陶系的放射虫燧石岩 总被引：5，自引：1，他引：4
渭北奥陶系的放射虫燧石岩是在稳定的华北地台上形成的远洋沉积.它们产在赵老峪组深水碳酸盐地层的下部,并以层位稳定、纹层发育、富含放射虫骨骼、成岩交代组构清楚,以及在剖面上与薄层的硅质页岩呈韵律互层等为等征,表明是深水的放射虫软泥在成岩作用早期由生物蛋白石经溶解-再沉淀反应快速转变而成.这种产在地台上的远洋沉积虽不多见,却是海平面大规模上升及其伴生的重大地质事件的反映.渭北放射虫燧石岩的时代相当于中奥陶世卡拉道克期.当时正值全球性海平面上升,秦岭古海盆也在发生强烈扩张与俯冲,因此,华北地台南缘下沉,使渭北地区变成了弧后深水盆地的北部边缘.当时研究区的古地理位置也恰好处于低纬度的赤道附近.这些都为放射虫燧石岩的堆积提供了有利的条件.由于当时钙质浮游生物尚未大量兴起,所以其沉积作用不受CCD的控制,水深较之现代的类似物可能要浅得多. 相似文献
18.
Sedimentary history of the Tethyan basin in the Tibetan Himalayas 总被引：14，自引：0，他引：14
After an epicontinental phase, the sedimentary rocks in the Tibetan Himalayas document a complete Wilson cycle of the Neo-Tethyan (Tethys Ill) evolution between the Gondwana supercontinent and its northward drifting margin (Lhasa block) from the Late Permian to the Eocene.During the Triassic rift stage, the basin was filled with a huge, clastic-dominated sediment wedge with up to > 5 000 m of flysch in the northern zone. Widespread deltaic clastics and shallow-water carbonates of late Norian to earliest Jurassic age in the southern zone mark, in conjunction with decreasing tectonic subsidence, the transition to the drift stage.Some 4 500 m of Jurassic and Early Cretaceous shallow-water carbonates and siliciclastics accumulated on the Tethyan Indian passive margin. Deepening-upward sequences with condensed beds at their tops alternate with repeated progradational packages of shelf sediments. Extensive abyssal sediments with basaltic volcanics in the northern deep-water zone reflect continued ocean spreading and thermal subsidence. Paleomagnetic data, gained separately for the northern Indian plate and the Lhasa block, indicate that the Neo-Tethys reached its maximum width about 110 Ma ago with a spreading rate of 4.8 cm/year, before it commenced to close again.During the remnant basin stage in the Late Cretaceous and Paleogene, a shallowing-upward megasequence, capped by a carbonate platform, developed in the southern inner shelf realm. In the northern slope/basin plain zone, turbidites and chaotic sediments, derived from both the acretionary wedge and the steepening slope of the passive margin, accumulated. The depositional center of the remnant basin shifted southward as a result of flexural subsidence and southward overthrusting.The sediments from the Triassic to the Paleogene are tentatively subdivided into five mega-sequences, which are controlled mainly by regional tectonics. Climatic influence (e.g., carbonate deposition), due to northward plate motion, is partially subdued by terrigenous input and/or increased water depth. During the Oligocene and Miocene, crustal shortening led to rapid uplift and the deposition of fluvial molasse in limited basins. 相似文献