scispace - formally typeset
Search or ask a question
Author

Shengli Li

Bio: Shengli Li is an academic researcher from China University of Geosciences (Beijing). The author has contributed to research in topics: Sedimentary rock & Sedimentary depositional environment. The author has an hindex of 4, co-authored 8 publications receiving 61 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: In this article, the relative balance of volumetric abundance of sedimentary clasts in non-marine to marine sedimentary records is identified as the most important criterion for classification.
Abstract: Mud clasts are common in non-marine to marine sedimentary records, however, why lack a widely accepted classification scheme? We propose that it is the relative balance of volumetric abundance, sor...

36 citations

Journal ArticleDOI
TL;DR: In this article, the authors explore facies and architectural changes from tide-influenced deltas to tide-dominated estuaries in transgressive-regressive cycles, as well as their controlling factors.
Abstract: The East China Sea Shelf Basin was a back-arc basin located at the active continental margin of the western Philippine Sea Plate. This study explores facies and architectural changes from tide-influenced deltas to tide-dominated estuaries in transgressive–regressive cycles, as well as their controlling factors. Cores, wireline well-logs and seismic data allow the sedimentary architectures and models of the depositional systems to be reconstructed. In the Xihu Depression of the East China Sea Shelf Basin, the stratigraphic sequences of the Eocene Pinghu Formation are interpreted to be dominated by repeated phases of deltaic progradation, but with intervening transgressive phases only thinly developed as bioturbated, open-marine shelf deposits. The sequences of the overlying Oligocene Huagang Formation, in contrast, are interpreted as stacked, tide-dominated estuary units, alternating with only poorly preserved regressive half-cycles because of repeated, strong estuary down-cutting. The intervening unconformity in the succession corresponds to the Yuquan tectonic movements, which triggered a change from extensional to compressional settings in the Xihu Depression. In the Late Eocene, extension of the Xihu Depression led to moderately high rates of subsidence (163 m Ma ), and short-term sea-level falls led to multiple phases of deltaic progradations. After the Yuquan Movement, Early Oligocene compression brought overall lower rates of subsidence (110 m Ma ), as well as sea-level rise and stacked estuary development with significant tidal influence in the infill. The interaction of tectonics, sea-level change and sediment supply determined the nature of the depositional systems on the shelf during the entire period, whereas the sedimentary processes were key to reworking and shaping the facies distribution, geomorphology and architectures in the back-arc basin. This research provides an insight into spatial and temporal characterization of deltaic and estuarine systems, contributing to a better understanding of the mechanisms controlling a change in dominant coastline type, despite continued strong tidal influence.

22 citations

Journal ArticleDOI
TL;DR: In this paper, outcrops of the Lower Cretaceous deposits on the Lingshan Island are well exposed to illustrate flow transformations between turbidity currents and debris flows in shallow water and basin floor in a lacustrine basin.

11 citations

Journal ArticleDOI
TL;DR: Zhang et al. as discussed by the authors proposed three mass transport deposit (MTD) patterns related to canyon activity that occurred contemporaneously or epigenetically with it: well preserved MTDs, MTDs eroded by canyon migration, and MTDs dislocated by contemporaneous faults.
Abstract: Since 2017, a plenty of gas hydrates have been drilled in a new area of Shenhu, and good heterogeneity has been found throughout the spatial distribution of the reservoir. After distinguishing different sedimentary sequence types and matching their formation with slope deposition settings, this study proposes three mass transport deposit (MTD) patterns related to canyon activity that occurred contemporaneously or epigenetically with it: well preserved MTDs, MTDs eroded by canyon migration, and MTDs dislocated by contemporaneous faults. Based on seismic reflection characteristics, this study proposed methods of quantitatively analyzing sedimentary factors, such as measuring the turbidities flow rate in the canyon, and results are interpreted with respect to canyon activity. Combining the above parameters and their relationship with gas hydrate accumulation, fine-grained seals overlapping coarse MTDs reservoirs are found to be indispensable to gas hydrate accumulation, as they prevent the release of free gas. Based on grain size data of hydrate samples from drilling wells, multi-layered gas hydrate reservoirs capped by fine-grained sediments and overlapping mud show favorable hydrate-bearing prospects. The release of gas hydrates, however, is mostly caused by the lack of mud sealing in relation to canyon activity, such as turbidities flow erosion and contemporaneous fault breaking. Canyon migration with respect to MTDs may be the actual cause of erosion of overlapping syn-sedimentary layers, and high bottom flows may contribute to an increase in the release of free gas. It is believed that contemporaneous faults caused by unstable canyon walls may break the muddy over layers and decrease the accumulation pressure of gas hydrate bearing. Thus, according to the sedimentary characteristics of MTDs and the hydrate accumulation process, three responding accumulation or releasing patterns are proposed, which respond to the different types of MTDs distinguished above: a well-preserved MTD accumulation pattern; a canyon migration eroded MTD release pattern; and a micro-contemporaneous fault dislocated MTD release pattern.

8 citations


Cited by
More filters
Journal Article
Carl L. Amos1

305 citations

Journal ArticleDOI
TL;DR: In this article, detrital zircon U-Pb ages and whole-rock geochemical data for clastic rocks from flysch strata in the Shannan area were reported.
Abstract: The Upper Triassic flysch sediments (Nieru Formation and Langjiexue Group) exposed in the Eastern Tethyan Himalayan Sequence are crucial for unraveling the controversial paleogeography and paleotectonics of the Himalayan orogen. This work reports new detrital zircon U-Pb ages and whole-rock geochemical data for clastic rocks from flysch strata in the Shannan area. The mineral modal composition data suggest that these units were mainly sourced from recycled orogen provenances. The chemical compositions of the sandstones in the strata are similar to the chemical composition of upper continental crust. These rocks have relatively low Chemical Index of Alteration values (with an average of 62) and Index of Compositional Variability values (0.69), indicating that they experienced weak weathering and were mainly derived from a mature source. The geochemical compositions of the Upper Triassic strata are similar to those of graywackes from continental island arcs and are indicative of an acidic-intermediate igneous source. Furthermore, hornblende and feldspar experienced decomposition in the provenance, and the sediment became enriched in zircon and monazite during sediment transport. The detrital zircons in the strata feature two main age peaks at 225–275 Ma and 500–600 Ma, nearly continuous Paleoproterozoic to Neoproterozoic ages, and a broad inconspicuous cluster in the Tonian–Stenian (800–1200 Ma). The detrital zircons from the Upper Triassic sandstones in the study area lack peaks at 300–325 Ma (characteristic of the Lhasa block) and 1150–1200 Ma (characteristic of the Lhasa and West Australia blocks). Therefore, neither the Lhasa block nor the West Australia blocks likely acted as the main provenance of the Upper Triassic strata. Newly discovered Permian–Triassic basalt and mafic dikes in the Himalayas could have provided the 225–275 Ma detrital zircons. Therefore, Indian and Himalayan units were the main provenances of the flysch strata. The Tethyan Himalaya was part of the northern passive margin and was not an exotic terrane separated from India during the Permian to Early Cretaceous. This evidence suggests that the Neo-Tethyan ocean opened prior to the Late Triassic and that the Upper Triassic deposits were derived from continental crustal fragments adjacent to the northern passive continental margin of Greater India.

60 citations

Journal ArticleDOI
TL;DR: In this paper, the pore size distribution can be divided into five groups: Ⅰ-micro-pores, Ⅱ-micro pores, small pores, medium pore, and macro pores.

38 citations

01 Jan 2016
TL;DR: Wang et al. as mentioned in this paper analyzed high-resolution three dimensional seismic surveys, seismic characteristics, distributions and origins of these features, and presented a distribution map and geometrical parameters and spatial distribution patterns are summarized.
Abstract: Mass transport deposits and geological features related to fluid flow such as gas chimneys, mud diapirs and volcanos, pockmarks and gas hydrates are pervasive on the canyon dominated northern slope of the Pearl River Mouth basin of the South China Sea. These deposits and structures are linked to serious geohazards and are considered risk factors for seabed installations. Based on high resolution three dimensional seismic surveys, seismic characteristics, distributions and origins of these features are analyzed. A distribution map is presented and geometrical parameters and spatial distribution patterns are summarized. Results show that various groups of the mapped features are closely tied to local or regional tectonism and sedimentary processes. Mass transport complexes are classified as slides near the shelf break, initially deformed slumps on the flanks of canyons and highly deformed slumps on the lower slope downslope of the mouth of canyons. We propose them to be preconditioned by pore pressure changes related to sea level fluctuations, steep topography, and fluid and fault activities. Gas chimneys are mainly located in the vicinity of gas reservoirs, while bottom-simulating reflectors are observed within the gas chimney regions, suggesting gas chimneys serve as conduits for thermogenic gas. Mud diapirs/volcanos and pockmarks are observed in small numbers and the formation of pockmarks is related to underlying gas chimneys and faults. This study aims at reducing risks for deep-water engineering on the northern slope of South China Sea. (C) 2016 Elsevier Ltd. All rights reserved.

34 citations