Platform Margin Research Articles

Syn-rift carbonate platforms in space and time: testing and refining conceptual models using stratigraphic and seismic numerical forward modelling

Abstract Understanding and predicting architecture and facies distribution of syn-rift carbonates is challenging owing to complex control by climatic, tectonic, biological and sedimentological factors. CarboCAT is a three-dimensional stratigraphic forward model of carbonate and mixed carbonate–siliciclastic systems that has recently been developed to include processes controlling carbonate platform development in extensional settings. CarboCAT has been used here to perform numerical experiment investigations of the various processes and factors hypothesized to control syn-rift carbonates sedimentation. Models representing three tectonic scenarios have been calculated and investigated, to characterize facies distribution and architecture of carbonate platforms developed on half-grabens, horsts and transfer zones. For each forward stratigraphic model, forward seismic models have also been calculated, so that modelled stratal geometries presented as synthetic seismic images can be directly compared with seismic images of subsurface carbonate strata. The CarboCAT models and synthetic seismic images corroborate many elements of the existing syn-rift and early-post-rift conceptual model, but also expand these models by describing how platform architecture and spatial facies distributions vary along-strike between hanging-wall, footwall and transfer zone settings. Synthetic seismic images show how platform margins may appear in seismic data, showing significant differences in overall seismic character between prograding and backstepping stacking patterns.

Cambrian Ordovician sedimentary facies and its evolution in Tadong area

In order to clarify the sedimentary development law under the Cambrian Ordovician regional stratigraphic framework in Tadong area, and lay a theoretical foundation for further oil and gas exploration in the study area. The distribution, characteristics and evolution of main sedimentary facies belts of Cambrian Ordovician are studied by means of drilling core observation, cast thin section identification, logging curve feature analysis, seismic profile and well connection profile. The results show that the Cambrian middle lower Ordovician in Tadong area is equivalent to a second-order sequence and can be further divided into 12 thirdorder sequences. Each third-order sequence is mainly composed of transgressive and highstand tracts. Carbonate platform margin beach facies and Reef (mound) beach complex facies are favorable reservoir development facies belts in this area; Under the regional stratigraphic framework, three types of sedimentary facies can be identified in Cambrian Ordovician, and a total of 10 subfacies are developed; The evolution of sedimentary facies is mainly controlled by the rise and fall of sea level, which is characterized by the migration of platform margin facies and the change of platform facies.

Paleomagnetism of the Sette-Daban Meso-Neoproterozoic magmatic complex of the southeastern margin of the Siberian platform

The interval of ~ 1000 - ~ 900 Ma is one of the key ones in the history of the evolution of the Siberian Platform. At this time, the formation of the neoproterozoic supercontinent Rodinia took place, which undoubtedly found its reflection in the geological annals of Siberia. A reflection of the kinematics of the Siberian platform is its apparent pole wander path (APWP), the development of which will help to clarify the geodynamic in which the platform was at the beginning of the Neoproterozoic. However, not many objects of this age are known within the Siberian Platform, suitable for performing paleomagnetic determinations. The consequence of this is a very limited number of existing reliable poles, obtained either from sedimentary rocks with very imprecise age limits, or from rocks of the Yenisei Ridge and Taimyr with an ambiguous structural position. This paper presents the results of paleomagnetic studies of the Proterozoic igneous rocks of the Sette-Daban complex of the southern Verkhoyansk region, the formation of which took place ~ 1000-970 Ma ago. Detailed thermal magnetic cleaning made it possible to reveal the high-temperature (HT) characteristic component in a significant part of the samples. It has maximum unblocking temperatures of about 580 ° C, lying in the region of the Curie point of magnetite. The average direction of the characteristic component for the sills sampled in the valley of the Yudoma, coincides with the direction obtained earlier on the same bodies. The calculated paleomagnetic pole for the intrusive bodies of the Sette-Daban magmatic complex (Plat = 5.8 °, Plong = 182.9 °, dp / dm = 9.0 ° / 14.4 °) confirms and refines the previously obtained pole for the rocks of this complex, and also indicates that Siberia in the range of ~ 970-1000 Ma was located in the northern hemisphere in tropical latitudes (~ 26 ° N). The analysis of the available geochronological and geochemical data, coupled with new paleomagnetic data, made it possible to clarify the age of the Sette-Daban magmatic event and limit it within ~ 970-1000 Ma.

Seismic-scale geometries and sequence-stratigraphic architecture of Early Cretaceous syn-post rift carbonate systems, Presalt Section, Brazil

Abstract Regional and detailed seismic stratigraphic analyses of Early Cretaceous (Aptian) presalt carbonate sections from offshore Brazil reveal the complex stratigraphic architecture of late- and post-rift lacustrine carbonate systems. The lateral and vertical distribution of calibrated seismic facies within this framework highlights the evolution through time of the carbonate system and bathymetry of the host lacustrine basin. Despite the simple, largely abiotic and microbial components, lacustrine carbonate accumulations formed complex geometries that closely resemble those observed from marine systems, suggesting that a downward-tapering carbonate production profile must have occurred. The complexity of the stratigraphic architecture reflects lateral variations in subsidence patterns combined with the interference of the basement topography, palaeowind directions and basinal filling patterns. Well-imaged clinoforms several hundred metres high attest to both the existence of significant lake-bottom topography, locally in excess of 800 m, and the occurrence of deep water at time of deposition. Platform margin trajectory and vertical and lateral architecture of clinoform packages through time reveal distinct sequence boundaries that can be correlated in detail only locally, demonstrating the impact of syndepositional tectonics, and possibly recurrent isolation of smaller lakes during lowstands. Depositional models from this study fill a gap in current understanding of lacustrine carbonate systems and offer a template for exploration and appraisal of the presalt play.

Chapter 2 Tectonostratigraphy of the eastern part of the Oman Mountains

Abstract This chapter provides comprehensive descriptions of 52 numbered formations/rock units of the Southeastern Oman Mountains, based on available literature. The oldest eight siliciclastic and carbonate formations are positioned below the ‘Hercynian’ Unconformity. The overlying formation (9–16) mostly represent carbonates which accumulated in a passive margin platform setting during or after the opening of the Neo-Tethys Ocean. The passive margin slope and platform collapsed during the late Cretaceous because of the obduction of the Semail Ophiolite along with the deep marine Hawasina sedimentary rocks. The collapsing passive margin interval was recorded within the syn-obductional Aruma Group (17; Muti Formation). Above this formation are the allochthonous units (18–42) of the tectonically lower Hawasina deep-sea basin and the structurally overlying Semail Ophiolite. The former contains Permian to Upper Cretaceous formations, while the latter is Cenomanian in age. Above the allochthonous rocks, the Neo-autochthonous formations were deposited, starting with the post-obductional uppermost Cretaceous Aruma Group (43; Al-Khod Formation) until the Quaternary deposits (52). All these formations/rock units are depicted on an accompanying map and stratigraphic chart.

Early Aptian rudist faunas from the Taurides (Southern Turkey): their stratigraphic, palaeogeographic and palaeobiogeographic significance

The eastern Taurides yield an early Aptian rudist fauna including Agriopleura libanica and Offneria murgensis, two key members of the Arabo-African biome, reported for the first time in Turkey. The presence of this assemblage which closely resembles that of the Shu'aiba Formation of Saudi Arabia, Oman and the United Arab Emirates, fills a distributional, geographical gap between its Arabian, North African and Apulian occurences. The rudist fauna and the composition of the associated micropalaeontological elements suggest an early Bedoulian age and a close palaeogeographic proximity with the regional outer platform margin. The presence in the Taurides of an Arabo-African fauna is consistent with the palaeotectonic placement of the Anatolides-Taurides in between the Arabian promontory and the peri-Adriatic zone.

Seismogeological characteristics, model of geological structure and oil and gas potential of the Laptev Sea shelf

Analysis of seismic cross sections in the Laptev Sea showed that a sedimentary basin is developed in the western part of the water area, the thickness of platform deposits in which is 15–20 km. A complex interpretation of geological and geophysical materials on the continental margin of the Siberian platform and the Laptev Sea water area was carried out, seismogeological models of sedimentary complexes on the continent and in the sea were compared, and gravity and magnetic anomalies were analyzed. The research results showed that the western part of the Laptev Sea, in geological terms, is a northern continuation of the Siberian platform. The oil and gas potential of this part of the water area will be associated with the Upper Proterozoic-Middle Paleozoic carbonate deposits and Permian-Mesozoic terrigenous sedimentary complexes.

Hydrocarbon accumulation and exploration prospect of mound-shoal complexes on the platform margin of the fourth member of Sinian Dengying Formation in the east of Mianzhu-Changning intracratonic rift, Sichuan Basin, SW China

Drilling, seismic and logging data were used to evaluate the hydrocarbon accumulation conditions of the mound-shoal complexes in the platform margin of the fourth member of Sinian Dengying Formation in the east side of the Mianzhu-Changning intracratonic rift in the Sichuan Basin. The four understandings are: (1) The platform margin belt of the Deng 4 Member can be divided into three sections, northern, middle and southern; the middle section is at the core of the Gaoshiti-Moxi paleouplift and the structural high now, while the southern and northern sections are at the slope of the paleouplift and the structural lows now; the three sections have similar development characteristics and reservoir features of platform margin mound-shoal complex. (2) In the margin of the east side of the rift, there are several faults nearly perpendicular to the platform margin belt, the faults divide the platform margin belt into rugged paleo-landform, and the high part developed platform margin mound-shoal complexes and the reservoirs are good in physical properties, while the low part developed inter-beach depression and no mound-shoal complexes, where the reservoirs are poor in physical properties. (3) The six groups of faults nearly perpendicular to the platform margin belt divide the platform margin belt into seven large mound-shoal complexes which have similar hydrocarbon accumulation conditions and accumulation evolution process and are rich in petroleum. (4) The inter shoal depressions between the mound-shoal complexes are characterized by tighter lithology, which can block the updip direction of the mounds and shoals at the lower part of the slope of the paleouplift and are favorable for the later preservation of mound-shoal gas reservoirs. This has been proved by Well Jiaotan 1 and Heshen 2 drilled successfully. The mound-shoal complexes on the platform margin of the structural slope area have a good exploration prospect.

Characteristics and main controlling factors of reservoirs in the fourth member of Sinian Dengying Formation in Yuanba and its peripheral area, northeastern Sichuan Basin, SW China

Abstract Based on the abundant outcrops and 3D seismic data in Yuanba and its surrounding areas in northeastern Sichuan Basin, the characteristics, main controlling factors and development regularities of reservoirs in the fourth member of Sinian Dengying Formation (shortened as Deng 4 Member) were analyzed comprehensively. The results show that the reservoirs were mainly developed in microbial dolomite associated with the microbial mound and dolarenite associated with grain beach, and had intergranular dissolution pores, inter-frame dissolution pores and karst caves as main storage space. The reservoirs were large in scale and strong in heterogeneity. The analysis of the reservoir genetic mechanisms shows that the reservoirs in the fourth member of Dengying Formation were the products of karstification on mound-beach facies deposited in the second episode of Tongwan movement. The karstification had the marks of eogenetic karstification such as granophyric karst system and half-dissociation zone. The reservoirs were controlled by the sedimentary facies belt, the mound beach facies was the decisive factor in reservoir development. Further analysis indicates that the Yuanba area had a geological background of well-developed platform margin mound beach facies, so mound beach bodies can be taken as a favorable exploration target.

First report of reef formation from the Balkanide type of Triassic: the Tran Formation (Upper Triassic) near the village of Gorna Sekirna, SW Bulgaria

Sphinctozoa skeletons were the main builders in microbial-sponge boundstones and cementstones. Syndepositional lithification of associated automicrite and marine phreatic cementation by radial fibrous and radiaxial calcite favored stabilization and growth of skeleton-cement reefs across a central reef area (close to a platform margin), but without forming a wave-resistant reef framework. Storm-influenced destruction of the buildups and subsequent reworking by waves and currents produced bioclastic-intraclastic grainstones.

Sedimentary characteristics of the Lower to Middle Ordovician Calathium reefs in the northwestern Tarim Basin, NW China

Recently, geologists are paying more and more attention to the Ordovician reefs in the Tarim Basin of China for related petroleum potential. This work presents a systematic study on the sedimentary characteristics of two well-exposed Lower to Middle Ordovician reefs of the Tarim Basin, one in the Yingshan Formation and the other in the Yijianfang Formation. The organism types, petrography and its sedimentary characteristics were analyzed based on detailed field and thin-section observations. The reef in the Yingshan Formation is identified as a patch reef that developed in open-platform environment and was distinguished four units, including the base facies, reef-core facies, reef-flank facies and sealing facies. In contrast, the reef in the Yijianfang Formation is a platform margin reef and was distinguished three units, including the base facies, reef-core facies and sealing facies. Both reefs had experienced phases of colonization, vertical aggradation and capping. However, the sea-level trends are different: reefs in the Yingshan Formation appear to reflect the sea-level rise with the subsequent fall, whereas reefs in the Yijianfang Formation appear to have been formed in the reverse order. This study improves the understanding of the sedimentary environments where reefs develop and provides guidance for exploration potential petroleum reservoirs in the Tarim Basin.

Late Pennsylvanian carbonate platform facies and coral reef: new insights from southern China (Guizhou Province)

The Pennsylvanian is characterized by intense paleoenvironmental changes related to glacio-eustatic sea-level fluctuations and major tectonic events, which affected the evolution of biocommunities. Most known Pennsylvanian tropical reefs and mounds are predominantly composed of calcareous algae (e.g. phylloid algae, Archaeolithophyllum), calcareous sponges, fenestrate bryozoans, Tubiphytes, and microbialites. However, in Houchang (southern China), the Late Pennsylvanian carbonate platform records a large coral reef lacking any analogs in age (Gzhelian), size (80–100 m thick) and composition (high biodiversity). The large coral reef developed at the border of the Luodian intraplatform basin. The intraplatform basin is characterized by the deposition of green algal grainstone, coated grain grainstone and bioclastic packstone, grainstone, floatstone and rudstone in shallow-waters. In the deep-water shelf, lithofacies are composed of burrowed bioclastic wackestone, microbioclastic peloidal packstone, grainstone, and fine-grained burrowed wackestone and packstone. In this context, the coral reef developed on a deep-shelf margin, in a moderate to low energy depositional environment, below the FWWB. The scarcity of Pennsylvanian coral reefs suggests global unfavorable conditions, which can be attributed to a complex pattern of several environmental factors, including seawater chemistry (aragonite seas), paleoclimatic cooling related to continental glaciation, and the biological competition with the more opportunistic and adaptive phylloid algal community that occupied similar platform margin paleoenvironments. The existence of the large Bianping coral reef in southern China, as well as a few additional examples of Pennsylvanian coralliferous bioconstructions, provides evidence that coral communities were able to endure the Late Paleozoic fluctuating paleoenvironmental conditions in specific settings. One of such settings appears to have been the deep shelf margin, where low light levels decreased competition with the phylloid algal community.

CARBONATE CLASTS FROM CRETACEOUS CONGLOMERATE DEPOSITS OF THE POSTĂVARU MASSIF (SOUTHERN CARPATHIANS, ROMANIA) – DEPOSITIONAL ENVIRONMENTS AND BIOSTRATIGRAPHIC REMARKS

The objective of this study is to describe the composition of the carbonate elements from the upper Albian–Cenomanian Postăvaru Conglomerates. Eight sections were studied. Two major types of conglomerates are identified in the field and thin sections: polymictic orthoconglomerates and paraconglomerates. Carbonate clasts are dominant in both types of conglomerates. Other subordinated clasts are composed of quartzites, sericite-chlorite schists and gneisses. Facies data allow reconstructing the depositional environments, while microfossil assemblages were used to establish the age of the studied carbonate clasts. The identified microfacies characterize a large variety of depositional environments, ranging from basin to shallow water environments (platform margin and inner platform depositional settings). The identified microfossil associations are indicative for three biostratigraphic intervals: Kimmeridgian–Tithonian, Tithonian–Berriasian and Berriasian–? lower Valanginian.

Structural contraints of neotectonic activity in the eastern part of the Western Carpathians orogenic wedge

The eastern part of the Western Carpathians orogenic wedge covering the territory eastward from the 20° meridian could serve as an example for close relation between basement rock structural anisotropy and the neotectonic morphostructural pattern. The neotectonic evolution of the region has been guided by crustal deformations of the entire main Western Carpathian fault systems, defined by steeply dipping faults of NE-SW, NW-SE, S–N and E-W directions. The fault sets bound morphostructural units and form the base for the Quaternary neotectonic activity and landscape development of the region. Closely linked to Western Carpathian lineaments they reflect both the Moho topography and directional orientation of adjoining platform margins. The fault sets represent inherited, poly-stage structures genetically correlating to Cretaceous fold pattern of the Western Carpathians being repeatedly reactivated during Cenozoic times. Summarising vertical movement ratios among neotectonic units, particularly between the highest uplifted/subsiding blocks, we have found the maximal Quaternary movements rate of the region reaching ca 1315 m and neotectonic movements rate of 1710 m.

Late Quaternary tectono-sedimentary processes on an isolated offshore high marginal platform (NW Iberian Continental Margin)

Studies of the most surficial sedimentary record from passive continental margins provide crucial knowledge about sedimentary dynamics and its changes through recent geological times. These studies allow understanding in detail the influence of both tectonic activity and long-term bottom-current circulation over the Late Quaternary sedimentary dynamics. Using a large dataset of multibeam bathymetry, chirp and multi-channel seismic (MCS) records, ROV seabed direct observations and a magneto-chemical facies characterisation, we provide a well-dated record of the tectono-sedimentary processes on an isolated high marginal platform over the Late Quaternary. Our results display several structural and geomorphological features and tectonic pulses that indicate intense faulting, folding, and deformation of the most recent sedimentary cover. Furthermore, we document four main sedimentary systems acting at the study area and controlled by different water masses (MOW, LSW and NADW): the (hemi)pelagic, bottom current-controlled (hemi)pelagic, contourite and downslope sedimentary systems; as well as a new typology of contourite associated to giant depressions, named as pockmarks-related drift. The record also shows erosive features and extremely low sedimentation rates for the last 172 cal ka BP. Results suggest that the topographic configuration of the high marginal platform and reorganizations of the water masses associated to climate changes causes a constriction of the water masses that induce an enhancement of the bottom-current activity, favouring erosion, winnowing and redistribution of sediments. Therefore, this study provides new insight into the tectonic control and bottom current activity effect over the Late Quaternary sedimentary cover from an isolated and elevate offshore morphostructural province, located at the Galician Continental Margin.

The co-relationship of marine carbonates and evaporites: a study from the Tarim Basin, NW China

The coexistence of carbonates and evaporites is common for various petroliferous basins in geological periods globally. It holds much more significance to find out the interaction of these two. This paper expounds the macroscopical and microscopic relationship from petrography, facies, and geochemical analyses from core samples. The study area is dominated by successions of evaporites and carbonates, and three sulfate, five carbonates and mudstone lithofacies have been identified. And carbonates and evaporites are commonly lateral equivalents, both resulted from the similar sedimentary environment and chemical constituents. The intergrowth relationship was mainly reflected in the factors for their formation (including sea-level, evaporation, salinity, climate and so on), sedimentary cycle (including the vertical cycle and banded distribution) and the diagenetic transitions (including TSR, dolomitization, dedolomitization and dissolution). A depositional model has been developed that reveals a bull’s-eye pattern which was dominated by restricted carbonate platform and evaporitic platform with shoal and reef facies developed around the platform margins. With gypsum salts served as the caprock, favorable dolomite reservoir which largely resulted from the diagenetic transition and source of high quality can form a large reservoir.

Late Permian tectono-sedimentary setting and basin evolution in the Upper Yangtze region, South China: Implications for the formation mechanism of intra-platform depressions

Abstract The Upper Yangtze region in the northwestern part of the South China Block was situated in a relatively active tectonic zone during the Late Permian. The expansion of the South Qinling and Jinshajiang–Ailaoshan oceans to the north and south, active mantle plumes, and related magma upwelling in the plate margins have significantly influenced the evolution of this area. The sediments of the Upper Permian Wujiaping Formation and Changxing Formation developed in the Upper Yangtze region are typical intracratonic basin sequences, which records the sedimentological and structural development during this period. To reconstruct the tectonic and paleogeographic framework of the Upper Yangtze region and to better understand the formation mechanism of intra-plate depressions, this study integrates drill core, well log, cross-sections and outcrop data to examine the lithological associations, stratigraphic thicknesses, and sedimentary facies, and further reconstruct the paleogeographic framework of the Late Permian sedimentary successions. Moreover, we integrate this data with 2D and 3D seismic data to describe the tectono-sedimentary framework of the intra-platform depressions. Based on the results, three primary tectono-sedimentary stages are delineated: (1) the Wujiaping Formation documents a rapid basalt eruption event on the southwestern edge of the Upper Yangtze region at the beginning of the Wuchiapingian stage, followed by a marine transgression which occurred from the northeast to the southwest with initial intra-platform depressions formed on the northern basin; (2) during the early Changsingian stage, the Upper Yangtze region comprised a variety of environments, including tidal flat-coast, mixed-platform, open-platform, slope, deep-water shelf, and platform margin reef and shoal, with a rapid sea-level rise and (3) the sea level reached its peak and then slowly dropped. The reefs developed along the intra-platform depressions during the late Changsingian stage. We suggest that the formation and evolution of the Late Permian basin sequences in the Upper Yangtze region were controlled by the plutonic magmatic activities and regional crustal extension. The proposed model has important implications for interpreting the rapid transformation of intra-platform depressions from uplift to depression, as well as the tectono-sedimentary differentiation framework in intracratonic basins.

A late Paleozoic extension basin constrained by sedimentology and geochronology in eastern Central Asia Orogenic Belt

According to sedimentary structure, petrology and sequence analysis from seven sections (S1–S7) across the West Ujimqin basin, the late Carboniferous to Permian sedimentary facies have been recognized and summarized as four sedimentary systems, i.e. the late Carboniferous-early Permian sedimentary system (SA) comprising the alluvial fan–delta–littoral facies, the late Carboniferous sedimentary system (SB) including the littoral facies–delta facies–platform margin facies, the early Permian sedimentary system (SC) characterized by delta front and prodelta facies, and the middle Permian sedimentary system (SD) with alternations of littoral and delta facies. According to the spatial and temporal distribution of the four sedimentary systems, the basin filling process can be divided into three stages. The first stage (324–290 Ma) is dominated by bidirectional terrigenous sediments containing the SA from alluvial fan to delta and littoral facies in the northwestern and the SB from littoral–delta to platform margin facies in the southern, respectively. The second stage (290–270 Ma) is characterized by delta front and prodelta facies of the SC marked by thick-bedded matrix-supported conglomerate, rapid accumulation of terrigenous sediments and volcanic debris, syn-sedimentary deformation and slump. The third stage (270–255 Ma) formed the SD with the alternations of littoral and delta facies, which is represented by complex terrigenous clasts and intra-basin carbonate. These shallow and proximal sedimentary systems from fan delta to littoral facies indicate that there was not oceanic sedimentary system in the eastern CAOB during the late Carboniferous to Permian except for some small red sea basins, which provides convictive evidence that the Paleo-Asian Ocean (PAO) had closed before the late Carboniferous. Detrital zircon dating reveals bidirectional provenances of the West Ujimqin basin, indicating that it was a limited basin between two uplifts, which implies presence of the late Paleozoic “basin and uplift” tectonic framework that developed on the eastern CAOB during the late Paleozoic.

An abrupt Middle-Miocene increase in fluid flow into the Leeward Margin Great Bahama Bank, constraints from δ44Ca and Δ47 values

The advection of seawater into the sediments deposited on the margins of Great Bahama Bank has been demonstrated to play in important role in ventilating the uppermost sediments, as well as supplying elements for diagenetic reactions deeper within the platform. Here, we implement a numerical model to calculate the rate of fluid advection at ODP Site 1003, using calcium isotopes as a tracer for fluid advection. A key parameter for this model, the rate of recrystallization of sediments, was constrained using the clumped isotope proxy. The model was tuned to existing datasets of clumped and carbonate calcium isotope measurements for this site. Results of this modeling effort indicate that, prior to ∼15 Ma, fluids were advected into the platform at a rate substantially lower than the present day. The rate of advection abruptly increased ∼13 Ma to a value greater than the present day. The increase in advective flux during the mid-Miocene coincides with a major reorganization of the platform from a ramp-like geometry to a steeper carbonate platform, indicating a change in the relative contributions of different mechanisms governing fluid flow on the platform margin and interior. This paper aims to explore the utility of using clumped and calcium isotopes to quantitatively reconstruct past fluid advection rates using this novel technique.

The Sedimentary Evolution During Late Triassic‐Jurassic Period and the Hydrocarbon Exploration Direction in the Eastern Part of the Qiangtang Basin, Tibet

AbstractBased on the field outcrops surveyed, combined with recent published the regional tectonic evolution and geochronology data, we analyzed the lithologies and rock associations of strata, identified the sedimentary facies types, and discussed the distribution sedimentary facies and the hydrocarbon accumulation in the eastern Qiangtang basin during the Late Triassic – Jurassic. Marked by regional unconformities, there are two tectono‐stratigraphic units (from the Carnian to the Norian and from the Rhaetian to the Kimmeridgian, respectively) in the eastern part of Qiangtang basin. We systematically described the distribution range, thickness variation and lithological characteristics of different formations in the tectono‐stratigraphic units. The Late Triassic‐Jurassic is dominated by marine facies and marine ‐ continental transitional facies. The marine ‐ continental transitional facies include deltaic and tidal‐lagoon facies. Marine facies including gentle carbonate slope, evaporative platform, restricted platform, littoral, neritic, bathyal and abysmal facies. The Carnian stage is dominated by littoral–neritic–bathyal–abysmal facies in the north Qiangtang depression otherwise the littoral–neritic facies in the south Qiangtang depression. The early Norian stage is dominated by carbonate gentle slope‐mixed continental shelf facies. The late Norian, Bajocian, Callovian and Kimmeridgian stage are dominated by tidal flat‐delta facies in the north Qiangtang depression and littoral‐neritic facies in the south Qiangtang depression. The Bathonian and Oxfordian stage are dominated by evaporative platform‐ restricted platform‐ mixed continental shelf facies. The sedimentary facies formed zones from north to south and extended in an E–W direction. The Eastern Lower Uplift (ELU) played an important role in the division zones of sedimentary facies from north to south. During the Bathonian and Oxfordian, the ELU developed below the sea level and controlled the distribution of restricted platform, evaporative platform and platform margin. We analyzed 20 source rock samples from the upper Triassic‐Jurassic. The total organic carbon (TOC) value from Qoimaco, Buqu and Adula Formations. of late Triassic‐Jurassic in the eastern Qiangtang basin are ranges from 0.17∼0.33% (average 0.28%), 0.05∼0.25% (average 0.15%) and 10.32∼28.78% (average 19.33%), respectively. Obviously, the Adula Fm. developed good source rocks. The values of Tmax and S1+S2 in the Adula formation are 459–461°C (average 460°C) and 6.75‐28.55 mg/g (average 18.18mg/g), indicating that the Adula source rock has reached high‐over‐maturity stage. The bathyal, gentle slop and platform facie belts of the Upper Triassic can configurate the good hydrocarbon prospects in the northeastern area of the Qiangtang basin.