共查询到20条相似文献，搜索用时 15 毫秒
1.
T.R. Charlton A.J. Barber A.J. McGowan R.S. Nicoll E. Roniewicz S.E. Cook S.T. Barkham P.R. Bird 《Journal of Asian Earth Sciences》2009,36(4-5):341-363
The palaeontologically rich and lithologically diverse Triassic successions of Timor provide a key stratigraphic and palaeontological link between northwestern Australia and other terranes of former eastern Gondwana (present-day Southeast Asia). Timor is now located in the zone of collision between the northern margin of the Australian continent and island arc terranes bordering the Eurasian plate, with the Triassic successions exposed in a fold-and-thrust belt and an extensive mélange complex. Three formal lithostratigraphic units have been defined previously within the main Triassic succession in Timor (Niof, Aitutu and Babulu formations), with a fourth, the Wai Luli Formation, primarily Jurassic in age but extending down into the Triassic. The Niof Formation (Anisian to Ladinian, possibly also Early Triassic) is a fine-grained deepwater succession, succeeded conformably by the Aitutu and Babulu formations (Ladinian to Norian/Rhaetian), which were deposited contemporaneously, with the Aitutu Formation continuing locally into the Lower Jurassic. The Aitutu Formation consists of deep shelf limestones interbedded with shales and marls, while the Babulu Formation is a deltaic to turbiditic siliciclastic succession. The Late Triassic to Jurassic Wai Luli Formation is characterised by marine shales and marls.Informal stratigraphic units include the Cephalopod Limestone Facies, a Rosso Ammonitico-type deposit, which contains an extremely rich fossil fauna (particularly ammonoids) and ranges through the entire Triassic; and the Fatu Limestone and Pualaca Facies which consists of shallow to marginal marine carbonates (mud mounds, oolitic limestones and reefs) restricted to the Late Triassic. Facies diversity was low during the Early Triassic and Anisian, but became more pronounced from the Ladinian and continuing through the Late Triassic, probably as a consequence of renewed tectonic extension. Triassic extension was not associated with major volcanism, unlike a previous phase of extension in the Early Permian.The Cablac Limestone Formation, originally defined as a Miocene stratigraphic element, is now recognised to be at least partly Late Triassic–Early Jurassic in age, with lithologies comparable to parts of the Fatu Limestone. The stratigraphy of these shallow marine carbonate sequences is clearly in need of rigorous revision, but it is not yet possible to suggest appropriate redefined formations. 相似文献
2.
Integrated biostratigraphic studies are undertaken on the newly discovered Gondwana successions of Purnea Basin which have been recognized in the subsurface below the Neogene Siwalik sediments. The four exploratory wells, so far drilled in Purnea Basin, indicated the presence of thick Gondwana sussession (± 2450m) with varied lithological features. However, precise age of different Gondwanic lithounits of this basin and their correlation with standard Gondwana lithounits is poorly understood due to inadequate biostratigraphic data.Present biostratigraphic studies on the Gondwana successions in the exploratory wells of PRN-A, RSG-A, LHL-A and KRD-A enable recognition of fifteen Gondwanic palynological zones ranging in age from Early Permian (Asselian-Sakmarian) to Late Triassic (Carnian-Norian). Precise age for the Gondwanic palynological zones, recognized in the Purnea Basin and already established in other Indian Gondwana basins, are provided in the milieu of additional palynological data obtained from the Gondwana successions of this basin.The Lower Gondwana (Permian) palynofloras of Purnea Basin recorded from the Karandighi, Salmari, Katihar and Dinajpur formations resemble the palynological assemblages earlier recorded from the Talchir, Karharbari, Barakar and Raniganj formations respectively, and suggests the full development of lower Gondwana succession in this basin. The Upper Gondwana (Triassic) succession of this basin is marked by the Early and Middle to Late Triassic palynofloras that resemble Panchet and Supra-Panchet (Dubrajpur/Maleri Formation) palynological assemblages, and indicates the occurrence of complete Upper Gondwana succession also in the Purnea Basin.The lithological and biostratigraphic attributes of Gondwana sediments from Purnea, Rajmahal and western parts of Bengal Basin (Galsi Basin) are almost similar and provides strong evidences about the existence of a distinct N-S trending Gondwana Graben, referred as the Purnea-Rajmahal-Galsi Gondwana Graben. Newly acquired biostratigraphic data from the Gondwana sediments of CHK-A, MNG-A and PLS-A wells from central part of Bengal Basin and Bouguer anomaly data suggest that these wells fall in a separate NE-SW trending graben of “Chandkuri-Palasi-Bogra Gondwana Graben”. Although, the post-Gondwana latest Jurassic-Early Cretaceous Rajmahal Traps and and intertrappean beds succeed the Upper Gondwana successions in Rajmahal, Galsi and Chandkuri-Palasi Gondwana basins, but not recorded in the drilled wells of Purnea Basin, instead succeeded by the Neogene Siwalik sediments. 相似文献
3.
辽西凌源牛营子盆地晚三叠世--中侏罗世地层层序及区域对比 总被引：12，自引：0，他引：12
本文根据重新理清的辽西凌源牛营子盆地晚三叠世-中侏罗世地层层序及时代,讨论其区域地层对比.晚三叠世晚期的邓杖子组是一套崩滑流为主的碳酸盐角砾,其为区域印支期构造运动的造山记录,与京西、冀北杏石口组、辽西北票羊草沟组(坤头菠罗组)可以对比;早侏罗世水泉沟组与京西、冀北南大岭组、辽西北票兴隆沟组层位相当,且各组火山岩时代基本相同;中侏罗世早期郭家店组底部含煤段与京西上窑坡组、冀北下花园组中部、辽西北票组中上部植物组合面貌一致;中侏罗世中期郭家店组砾岩段是燕山期构造变形主幕的产物,北京西山龙门组、冀北下板城下花园组上部、辽西北票海房沟组都是该期的记录,层位相当;辽西中侏罗世中晚期蓝旗组底部的时代为158±1Ma,与京西、冀北髫髻山组安山岩的同位素年龄总体一致.这说明差异较大的燕山板内造山带三叠纪-中侏罗世盆地的沉积记录显示了相似的演化规律. 相似文献
4.
《International Geology Review》2012,54(16):2000-2014
Basement exposed in the Placer de Guadalupe–Plomosas uplift in northern Mexico provides important clues for the geologic evolution of the region. The stratigraphic units form stacked thrust sheets of psammitic and calcareous formations, interlayered with magmatic rock. The eastern calcareous and quartzite formations exhibit structures associated with ductile deformation, whereas the upper stratigraphic units only contain structures formed via younger brittle deformation. Porphyry interlayered in the upper Plomosas Formation has a U-Pb zircon age of 171 ± 1 Ma. This age is consistent with its stratigraphic position, interbedded quartzarenites with a maximum depositional age of ~168 Ma. Granite flakes within the Horquilla Formation are dated at 209 ± 3 Ma, and the La Viñata quartzite exhibits a maximum age of ~193 Ma. The Upper Plomosas Formation correlates well with the arc-related Middle Jurassic Nazas Formation of northeastern Mexico, constituting the first report of a Jurassic continental margin arc outcrop in the ‘Central Mexican Gap zone’. We document Late Norian to Bajocian ages for the stratigraphic units cropping out in the Placer de Guadalupe area. The Jurassic age cluster indicates that the Nazas Arc magmatism in the region occurred during the Late Triassic and ended in the Middle Jurassic times. Permian ages previously assigned to these rocks and the occurrence of a Permo–Triassic deformation event have to be dismissed. 相似文献
5.
A. N. F. Edilbi M. A. Maleko A. Y. Mohamed S. A. Bowden 《Arabian Journal of Geosciences》2017,10(3):73
Here, we report that a lithostratigraphic unit that outcrops at Sararu village, 6 km northeast of Qumri village that had previously been assigned to the Baluti Formation is not Triassic in age and therefore can not be a correlative equivalent of the Baluti Formation. The outcropping unit at Sararu comprises intercalation of calcareous mudstones and limestones, and is indeed lithologically similar to the Baluti Formation (Late Triassic). The Baluti Formation (also known as the Baluti Shale) is known from a typical section found at the Gara Anticline and from many deep drilled oil exploration wells. It is generally composed of alternations of the shales, limestones, dolomites, and dolomitic limestones. It is underlain by the Kurra Chine Formation (Upper Triassic) and overlain by the Sarki Formation (Lower Jurassic). In this study, detailed field observations, an assessment of stratigraphic successions, studies of microfossils such as age-specific planktonic foraminifera (e.g., Globotruncana bulloides), and age-specific biomarkers (oleanane index and C28/C29 regular sterane index) reveal that the lithostratigraphic unit at Sararu village can not be a correlative equivalent of the Baluti Formation, and it is more likely from the Upper Cretaceous. There are a number of Upper Cretaceous formations found in this part of Kurdistan, but based on fossil-type and palaeoenvironmental associations, the Hadiena Formation, from the Upper Cretaceous, is considered as the most likely correlative equivalent to the calcareous mudstone and limestone succession found at Sararu village. 相似文献
6.
鄂尔多斯西南缘前陆盆地沉积物物源分析及其构造意义 总被引：32，自引：0，他引：32
前陆盆地充填沉积物中岩屑的分散形式和砂岩成分研究对确定物源区的逆冲事件、构造背景和与沉积物对应的物源层十分有效。通过对鄂尔多斯西南缘安口地区上三叠统沉积剖面系统采样测定发现，沉积物物源为一套变质碎屑岩和变质火山岩，为东祁连褶皱逆冲带中的陈家河组（Ｏ３ｃｈ）和葫芦河组（Ｚ－Ｏ２ｈｌ）。而西南缘千阳县上侏罗统砾岩物源为陇山群（Ｐｔ２ｌｎ）。上三叠统地层的物源分散形式为混合型，而上三叠统和上侏罗统两套地层统一的分散型式为倒序型，它是两期逆冲活动的沉积响应。根据鄂尔多斯西南缘安口地区上三叠统沉积物的ＱｍＦＬｔ端元成分作砂岩三角投影图，确定晚三叠世鄂尔多斯西南缘盆地性质为发育于碰撞造山带之前陆的前陆盆地。其物源为再旋回活动的褶皱逆冲断块 相似文献
7.
鄂尔多斯西南缘前陆盆地沉积物物源分析及其构造意义 总被引：3，自引：0，他引：3
前陆盆地充填沉积物中岩屑的分散形式和砂岩成分研究对确定物源区的逆冲事件、构造背景和与沉积物对应的物源层十分有效。通过对鄂尔多斯西南缘安口地区上三叠统沉积剖面系统采样测定发现，沉积物物源为一套变质碎屑岩和变质火山岩，为东祁连褶皱逆冲带中的陈家河组（Ｏ３ｃｈ）和葫芦河组（Ｚ－Ｏ２ｈｌ）。而西南缘千阳县上侏罗统砾岩物源为陇山群（Ｐｔ２ｌｎ）。上三叠统地层的物源分散形式为混合型，而上三叠统和上侏罗统两套地层统一的分散型式为倒序型，它是两期逆冲活动的沉积响应。根据鄂尔多斯西南缘安口地区上三叠统沉积物的ＱｍＦＬｔ端元成分作砂岩三角投影图，确定晚三叠世鄂尔多斯西南缘盆地性质为发育于碰撞造山带之前陆的前陆盆地。其物源为再旋回活动的褶皱逆冲断块。 相似文献
8.
9.
10.
The Rajmahal Traps were discovered in the Panagarh area, West Bengal, during the exploration for coal resources. A Gondwana succession was found beneath the traps, consisting of the Early Cretaceous Intratrappean Rajmahal Formation, the Early Triassic Panchet Formation and the Late Permian coal-bearing Raniganj Formation. The present palynological study was aimed at confirming the age of the Panchet Formation. As a result of this study it has been found that Jurassic sediments are also included in the Panchet Formation. The study has revealed that the Panchet Formation, defined on a lithological basis, is a time-transgressive unit extending from the Early Triassic to the Late Jurassic, with a phase of non-deposition between the Middle Triassic and Middle Jurassic. 相似文献
11.
12.
The Jurassic succession of western Iraq includes the Ubaid, Hussainiyat, Amij, Muhaiwir, and Najmah formations. Each formation is composed of basal clastic unit overlain by upper carbonate unit. Extensive and huge erosional unconformity occurred at the Triassic–Jurassic boundary due to marked shifting of structural (E–W) strike of the Triassic (Rhaetic) Zor Hauran Formation to (NE–SW) Jurassic formations. Sea level falling (lowstand system tracts) would result in the progradation of the land on the expense of the sea forming the recognizable progradation of the fluvial and deltaic deposits of the lower clastic units of the Jurassic formations, whereas sea level rising (highstand system tract), i.e., sea prograding, causes deposition of the carbonate units of the Jurassic formations system. This progradation resulted to various carbonate environments of deposition ranging from subtidal, intertidal, to supratidal. The main target on most of the exploration blocks in the western part of Iraq focused on the lower Paleozoic successions, whereas prospects in Triassic, Jurassic, and lower Cretaceous targets are less extensive but may have significant potential on certain blocks in both stratigraphic and structural traps. The western part of Iraq was subjected to intermittent pulses of uplifting (sea regression) and subsidence (sea transgression) to form the Jurassic basin system in the area. The Jurassic formations lack the characteristics of petroleum systems. In contrast, in the central and northern parts of Iraq, the Jurassic formations (Najmah and Gotnia formations) were deposited in subsiding basins in which the reservoir and sealed evaporitic rocks existed. In turn, in the western desert of Iraq, the Jurassic formations lack these petroleum system characteristics. Hence, it can be proposed that the petroleum–nonpetroleum inflection could be proposed in the east of area km 160. 相似文献
13.
The thermal maturity and source-rock potential of the Upper Palaeozoic and Mesozoic sediments in the Hecla field, Melville Island, Arctic Canada, have been studied using reflected-light microscopy and Rock-Eval pyrolysis. Approximately 250 polished whole-rock samples were examined and their reflectance (% R0, random) measured. In addition, approximately 100 samples were subjected to Rock-Eval/TOC analyses.Hydrogen-rich organic matter in the Schei Point Group sediments is dominated by alginite (Tasmanales), dinoflagellate cysts with minor amounts of sporinite, cutinite, resinite and liptodetrinite in an amorphous fluorescing matrix. Vitrinite reflectance in Cretaceous sediments ranges from 0.41 to 0.54%; in Jurassic sediments it ranges from 0.43 to 0.64% and in Triassic sediments from 0.50 to 0.65%. The Triassic Schei Point Group calcareous shales and marlstones contain organic matter mainly of marine origin, whereas the predominantly terrestially-derived organic matter present in the Jameson Bay (Lower Jurassic) and in the Upper Jurassic to Lower Cretaceous Deer Bay formations have ower TOC. Only the Ringnes Formation has a TOC content of equivalent to or greater than Schei Point source rocks. Within the Schei Point Group, the Cape Richards and Eden Bay members of the Hoyle Bay Formation are slightly richer in TOC than the Murray Harbour Formation (Cape Caledonia Member). Higher average TOC contents (>3.0%) have been reported in the Cape Richards and Eden Bay members in almost all Hecla drillholes.Variations in the level of thermal maturity of Mesozoic sediments in the Hecla field are a function of burial depth. The stratigraphic succession thickens towards the main Sverdrup Basin depocentre located in a N-NE direction. The pattern of the isoreflectance contours at the top of the Triassic (Barrow Formation) is similar to that of formation boundary lines of the same formations, an indication that present-day maturation levels are largely controlled by basin subsidence. 相似文献
14.
15.
黄陵穹隆东、西两翼上三叠统的精细对比 总被引：3，自引：0，他引：3
报道了采自于鄂西巴东县上三叠统沙镇溪组新层型剖面3种楔羽叶植物化石，即Sphenozamites marioni Counillon，Sph．fenshuilingensis Meng和Sph．cf．changi Sze。在分析秭归盆地上／中三叠系接触界面特征和化石组合带的基础上，指出盆地西缘上三叠统与下伏中三叠统为连续沉积，而东缘则呈假整合接触。依据黄陵穹隆东、西翼上三叠统的岩性特征、动植物化石和与下伏地层的接触关系，提出荆门—当阳盆地上三叠统王龙滩组和九里岗组可分别与秭归盆地沙镇溪组上部和中下部进行精细对比。 相似文献
16.
须家河组二段是川西坳陷中的区域气层。长期以来，地质分层采用岩石地层单位界面。这一界面的穿时性，造成了构造演化分析中的误差。笔者以钻井、测井和地震资料为主要研究对象，在引入地震反射“等时”约束条件的前提下，通过对须家河组长期基准面旋回层序及须二段中期基准面旋回层序的划分和对比，在建立高分辨率时间一地层格架的基础上，经过地震微相特征的仔细分析，确认须二段顶面属Ⅲ级整合界面。 相似文献
17.
BASIN-RANGE TRANSITION AND GENETIC TYPES OF SEQUENCE BOUNDARY OF THE QIANGTANG BASIN IN NORTHERN TIBET 相似文献
18.
Luis O'Dogherty Agustín Martín-Algarra Hans-Jürgen Gursky Roque Aguado 《International Journal of Earth Sciences》2001,90(4):831-846
Middle Jurassic radiolarites and associated pelagic limestones occur in the Rondaide Nieves unit of the Betic Cordillera, southern Spain. The Rondaide Mesozoic includes: (a) a thick succession of Triassic platform carbonates, comparable to the Alpine Hauptdolomit and Kössen facies; (b) Lower Jurassic pelagic limestones comparable to the Alpine Hierlatz and Adnet facies; (c) the Middle Jurassic Parauta Radiolarite Formation, described herein; and (d) a thin Upper Jurassic-Cretaceous condensed limestone succession. The Parauta Radiolarite Formation and associated limestones were studied with respect to stratigraphy, petrography, micropalaeontology (radiolarians, calcareous nanno- and microfossils) and facies. Radiolarite sedimentation occurred in the Middle Bathonian in a restricted and dysoxic deep Nieves basin, perched in the distal zone of a continental margin fringing the Tethyan ocean. This margin was adjacent to a young narrow oceanic basin between the South-Iberian margin and a continental block called Mesomediterranean Terrane. The Nieves basin was part of a marine corridor between the Proto-Atlantic and Piedmont-Ligurian basins of the Alpine Tethys. The regional tectonic position, the stratigraphical evolution since the Triassic, the age and the nature of the Mesozoic facies and the palaeogeographic relations to adjacent domains show striking analogies between the Betic Rondaide margin and coeval units of the Alps. 相似文献
19.
前人研究表明西藏南羌塘盆地存在中三叠世地层,然而一直以来缺乏确凿的古生物化石证据.在西藏改则县古姆乡座倾错地区原被划为晚三叠世日干配错组的地层中测制了两条剖面,在硅质岩样品中分析和鉴定出18属33种（含未定种）放射虫化石,主要分子包括Cryptostephanidium longispinosum（Sashida）、Eptingium manfredi Dumitrica、Falcispongus falciformis Dumitrica、Hindeosphaera spinulosa（Nakaseko et Nishimura）、Muelleritortis firmum（Gorican）、Oertlispongus inaequispinosus Dumitrica,Kozur et Mostler、Paroertlispongus chinensis（Feng）、Paroertlispongus hermi（Lahm）、Paroertlispongus weddigei Lahm、Paurinella aequispinosa Kozur et Mostler、Pseudostylosphaera coccostyla（Rüst）、Pseudostylosphaera compacta（Nakaseko et Nishimura）、Pseudostylosphaera gracilis Kozur et Mostler、Pseudostylosphaera japonica（Nakaseko et Nishimura）、Pseudostylosphaera nazarovi（Kozur et Mostler）、Pseudostylosphaera tenue（Nakaseko et Nishimura）、Triassocampe imitata Bragin、Triassospongosphaera triassica（Kozur et Mostler）.座倾错放射虫化石组合指示这段地层时代为中三叠世安尼期晚期-拉丁期早期.结合之前的工作积累,将南羌塘盆地三叠系划分为表示稳定型浅海相碳酸盐岩沉积的下三叠统孜狮桑组、表示半深海-深海相碎屑岩-硅质岩沉积的中三叠统座倾错组、上三叠统日干配错组以及上三叠统-下侏罗统萨门熊组.该发现为了解中三叠世南羌塘地区的真实面貌提供了地层学和古生物学证据,也进一步证明中三叠世南羌塘盆地不是陆地剥蚀区或隆起区,而是一种半深海-深海相沉积区. 相似文献
20.
从烃源岩特征、天然气组分、油气碳同位素、凝析油全烃和轻烃、储层沥青等方面对营山地区上三叠统和中、下侏罗统油气源特征进行了对比研究,阐明了营山地区上三叠统须家河组和中、下侏罗统油气的地球化学特征、成因和可能来源。研究表明营山地区上三叠统须家河组油气主要来自须家河组自身的煤系烃源岩,天然气以成熟腐殖型母质成因为主,而中、下侏罗统气藏产出的油气主要来自其自身的烃源岩。营山地区构造活动强烈,断层发育,使得部分井区中、下侏罗统产出的天然气特征与下伏产层极为相似,反映了断层对该井区附近的各层段有一定的沟通作用。中、下侏罗统地层在部分井区可能有上三叠统须家河组油气的侵入,须家河组烃源岩对中、下侏罗统油气成藏有一定贡献作用。 相似文献