塔里木盆地三叠系烃源岩有机岩石学特征与生烃评价   总被引：5，自引：1，他引：5  

肖贤明 《地球化学》1997,26(1):64-71

应用现代有机岩石学方法，配合有机地球化学方法，通过对塔里木盆地三叠系烃源岩的研究，认识了一种较特殊的烃源岩类型，其生烃母质以菌解无定形体为主，不仅其实测镜质组反射率Ｒ°具有明显抑制作用，而且其生烃早，“液态窗”范围介于镜质组Ｒ°为０．４０％－０．９５％之间。这类烃源岩生烃潜力较强（相当于ⅡＢ型干酪根），实际上已进入成熟－成烃峰期阶段，并广泛分布于塔北轮南及其以南地区，预测展布面积达１．０－１．５万  相似文献   

楚雄盆地晚三叠世古地理变迁   总被引：4，自引：1，他引：4       下载免费PDF全文

尹福光  万方  许效松  谭富文  陈明  汪正江 《沉积与特提斯地质》2004,24(3):52-57

楚雄盆地晚三叠世为一建立在扬子板块西缘前寒武纪基底之上的海相—海陆过渡相—陆相沉积盆地。中三叠世拉丁期—晚三叠世卡尼期沉积了一套深水的灰色薄层状粉砂质泥岩和泥质粉砂岩；诺利期早期以华坪隆起为界有两个沉降中心，华坪隆起以西的推覆体之上为广海陆架相的细碎屑岩沉积、远源浊积岩，以东为局限环境下的细碎屑岩沉积夹浊积岩；诺利期晚期为大规模的三角洲前缘砂体组成下超的复合体，古地理格局继续保持东西向分带，呈对称分布，盆地西部为陆相、海陆过渡相，盆地中部为海相沉积。瑞替期在原形盆地中形成舍资组的河流—滨岸沉积，在推覆体上形成白土田组的冲洪积物。总之，表现古地理变迁为一个由西东逐渐超覆、由下向上粒度逐渐变粗、由海相变为陆相的过程。  相似文献   

Palaeomagnetism and magnetostratigraphy of the Permian–Triassic northwest central Siberian Trap Basalts     

E.L. Gurevitch  C. Heunemann  V. Rad'ko  M. Westphal  V. Bachtadse  J.P. Pozzi  H. Feinberg 《Tectonophysics》2004,379(1-4):211-226

A detailed palaeomagnetic and magnetostratigraphic study of the Permian–Triassic Siberian Trap Basalts (STB) in the Noril'sk and Abagalakh regions in northwest Central Siberia is presented. Thermal (TH) and alternating field (AF) demagnetisation techniques have been used and yielded characteristic magnetisation directions. The natural remanent magnetisation of both surface and subsurface samples is characterised by a single component in most cases. Occasionally, a viscous overprint can be identified which is easily removed by TH or AF demagnetisation.The resulting average mean direction after tectonic correction for the 95 flows sampled in outcrops is D=93.7°, I=74.7° with k=19 and α₉₅=3.3°. The corresponding pole position is 56.2°N, 146.0°E.Unoriented samples from four boreholes cores in the same regions have also been studied. They confirm the reversed–normal succession found in outcrops. The fact that only one reversal of the Earth's magnetic field has been recorded in the traps can be taken as evidence for a rather short time span for the major eruptive episode in this region. However, there is evidence elsewhere that the whole volcanic activity associated with the emplacement of the STB was much longer and lasted several million years.  相似文献   

Mise en évidence d'un nouveau front de chevauchement dans l'Atlas tunisien oriental de Tunisie par sismique réflexion. Contexte structural régional et rôle du Trias salifère     

Sami Khomsi  Mourad Bédir  M. Ghazi Ben Jemia  Hédi Zouari 《Comptes Rendus Geoscience》2004,336(15):1401-1408

Structural interpretations of newly acquired seismic lines in northeastern Tunisia allow us to highlight a new thrust front for the Atlasic range of Tunisia, in contrast to the previously Zaghouan fault thrust Dorsale zone. This new thrust front takes place on weakness tectonic zones, materialized by inherited faults anchored on the pre-Triassic basement. This front seems to be a paleogeographic trend controlling structural style and basin fill with a synsedimentary activity. The front is expressed by reverse faults, thrust faults, back thrusting, and decollement structures. To cite this article: S. Khomsi et al., C. R. Geoscience 336 (2004).  相似文献   

Latest Jurassic–earliest Cretaceous radiolarian fauna from the Xialu chert in the Yarlung Zangbo suture zone, southern Tibet: Comparison with coeval western Pacific radiolarian faunas and paleoceanographic implications     

Atsushi  Matsuoka  Qun  Yang  Masahiko  Takei 《Island Arc》2005,14(4):338-345

Abstract The Xialu chert radiolarian fauna is latest Jurassic–earliest Cretaceous in age (Pseudodictyomitra carpatica zone) and contains many taxa in common with coeval northern hemisphere middle‐latitude (temperate) radiolarian faunas represented by the Torinosu fauna in southwest Japan. Common elements include Eucyrtidiellum pyramis (Aita), Protunuma japonicus Matsuoka & Yao, Sethocapsa pseudouterculus Aita, Sethocapsa (?) subcrassitestata Aita, Archaeodictyomitra minoensis (Mizutani), Stichocapsa praepulchella Hori and Xitus gifuensis (Mizutani). The Xialu fauna is less similar to low‐latitude (tropical) assemblages represented by the Mariana fauna. For this reason, the Xialu fauna is regarded as representative of a southern hemisphere middle‐latitude (temperate) fauna. A mirror‐image bi‐temperate provincialism to the equator in radiolarian faunas is reconstructed for the Ceno‐Tethys and Pacific Ocean in latest Jurassic–earliest Cretaceous time.  相似文献   

Unique Marine Olenekian-Anisian Boundary Section from South Primorye, Russian Far East     

Yuri D Zakharov Alexander M Popov Galina I Buryi 《中国地质大学学报(英文版)》2005,16(3):219-230

INTRODUCTION LateOlenekianandAnisianmarinedepositsin SouthPrimoryewerefirststudiedbyD.L.Ivanov,thechiefofageologicalteammakingreconnaissance workfortheconstructionofthetrans Siberianrail road.HecollectedEarlyandMiddleTriassicam monoidsonRussianIsland.Arep…  相似文献   

Halocinèse précoce associée au rifting jurassique dans l'Atlas central de Tunisie (région de Majoura–El Hfay)     

Dorra Tanfous Amri  Mourad Bédir  Mohamed Soussi  Hajer Azaiez  Lahoussine Zitouni  M. Hédi Inoubli  Kamel Ben Boubaker 《Comptes Rendus Geoscience》2005,337(7):703-711

Seismic and sequence stratigraphy analyses, petroleum-well control and surface data studies of the Majoura–El Hfay region in the Central Atlas of Tunisia had led to identify and calibrate Jurassic seismic horizons. Seismic stratigraphic sections, seismic tectonics analyses, isochron and isopach mapping of Jurassic sequences show a differentiated structuring of platform and depocentre blocks limited by deep-seated NE–SW, north–south east–west and NW–SE faults intruded by Upper Triassic salt. The early salt migration seems to have started by the platform fracturing during the Lower Liassic rifting event. These movements are fossilized by thickness variations of Jurassic horizons, aggrading and retrograding onlap and toplap structures between subsiding rim-syncline gutters and high platform flanks intruded by salt pillows and domes. The salt migration is also attested by Middle and Upper Jurassic space depocentre migrations. Around the Majoura–El Hfay study blocks bounded by master faults, Triassic salt have pierced the Cretaceous and Tertiary sedimentary cover in a salt diapir extrusion and salt wall structures. To cite this article: D. Tanfous Amri et al., C. R. Geoscience 337 (2005).  相似文献   

PETROLOGY 1.IGNEOUS PETROLOGY     

《Abstract of Chinese Geological Literature》2014,(2)

正20140707Bai Yunshan(Wuhan Center,China Geological Survey,Wuhan 430205,China);Duan Qifa Geological Characteristics and Tectonic Significance of Volcanic Rocks from Kenan Formation of the Upper Triassic in Zhahe Area,Southern Qinghai Province(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(2),  相似文献   

Progradational and backstepping shoreface deposits in the Ladinian to Early Norian Snadd Formation of the Barents Sea          下载免费PDF全文

Tore G. Klausen  Alf Ryseth  William Helland‐Hansen  Helge K. Gjelberg 《Sedimentology》2016,63(4):893-916

Shoreface sandstone deposits within the Early Carnian part of the Snadd Formation of the Norwegian Barents Sea can be traced for hundreds of kilometres in the depositional strike direction and for tens of kilometres in the depositional‐dip direction. This study uses three‐dimensional seismic attribute mapping and two‐dimensional regional seismic profiles to visualize the seismic facies of these shoreface deposits and to map their internal stratigraphic architecture at a regional scale. The shoreface deposits are generally elongate but show variable width from north‐east to south‐west, which corresponds to a sediment source in the northern part of the basin and a southward decrease in longshore sediment transport. The Snadd Formation presents an example of how large‐scale progradational shoreface deposits develop. The linear nature of its shoreface deposits contrasts with more irregular, cuspate wave‐dominated deltaic shorelines that contain river outlets, and instead implies longshore drift as the main sediment source. In map view, discrete sets of linear features bounded by truncation surfaces scale directly to beach ridge sets in modern counterparts. The shoreface deposits studied here are characteristic in terms of scale and basin‐wide continuity, and offer insight into the contrast between shallow marine deposition under stable Triassic Greenhouse and fluctuating Holocene Icehouse climates. Findings presented herein are also important for hydrocarbon exploration in the Barents Sea, because they describe a hitherto poorly understood reservoir play in the Triassic interval, wherein the most prominent reservoir plays have so far been considered to be found in channelized deposits in net‐progradational delta‐plain strata that form the topsets to shelf‐edge clinoforms. The documented presence of widespread wave‐dominated shoreface deposits also has implications for how the relative importance of different sedimentary processes is considered within the basin during this period.  相似文献   

Is Darwin's ‘Abominable Mystery’ still a mystery today?     

《Cretaceous Research》2016

Darwin described the Cretaceous diversification and subsequent rapid rise of flowering plants (angiosperms) as an “abominable mystery”: how could they have achieved worldwide ecological dominance by early Paleogene times when the oldest angiosperm fossils are only Cretaceous in age? However, recent phylogenetic and palaeobiogeographical analyses have suggested a much earlier, perhaps Triassic origin for the stem angiosperms. We suggest that the fossil record is accurately reflecting the rapid diversification of the crown angiosperms that molecular data suggests occurred in Cretaceous–early Palaeogene times, and which coincides with similar explosive diversifications that occurred in other parts of the terrestrial biota including insects, birds and mammals. Early, stem angiosperms are poorly represented in the fossil record for a combination of taphonomic and ecological reasons. We conclude that the reported evidence shows that the Darwin's “mystery” is in fact no mystery and confirms that it merely requires an appropriate reading of the fossil record.  相似文献