Shunli Li

Bio: Shunli 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 8, co-authored 26 publications receiving 160 citations. Previous affiliations of Shunli Li include China University of Petroleum & University of Texas at Austin.

Classification, formation, and transport mechanisms of mud clasts

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...

Growth of the paleo-Orinoco shelf-margin prism: Process regimes, delta evolution, and sediment budget beyond the shelf edge

Abstract: The first sedimentological characterization and correlation of onshore outcrop and offshore subsurface data (southern Columbus Basin) are presented for the paleo-Orinoco (Upper Miocene–Pliocene) shelf-margin prism, Trinidad Island, Trinidad and Tobago. The paleo–Orinoco River delta system and associated continental slope, which generated the 10-km-thick sedimentary prism, was a mixed river, tide, wave, and sediment-gravity flow system that tracked down to deep-water submarine fans. The analysis here includes: (1) an evaluation of delta-plain to deep-water turbidite sedimentary facies, which are seen in spectacular outcrops along the southwest, south, and southeast coasts of Trinidad Island, (2) well-log correlation of the same Upper Miocene–Pliocene strata across southern Trinidad and out to the southern part of the offshore Columbus Basin along an off-axis transect, because the main fairway into the most rapidly subsiding part of Columbus Basin is structurally complex, and few detailed data have been released for publication; and (3) use of published seismic data for reconstruction of clinoform morphology across the relatively undeformed segment of the margin, with quantitative sediment flux calculations and predictions. Paleo-Orinoco shelf-margin growth was generated by repeated (~<100 k.y. time scale) cross-shelf, regressive-transgressive transits (>100 km) of the Orinoco delta system, with internal variability in clinoform architecture and process-regime changes dur-

Change from tide-influenced deltas in a regression-dominated set of sequences to tide-dominated estuaries in a transgression-dominated sequence set, East China Sea Shelf Basin

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.

The effects of land subsidence and rehabilitation on soil hydraulic properties in a mining area in the Loess Plateau of China

Abstract: Land subsidence caused by underground coalmining gives rise to severe surface deformation and results in a number of soil cracks, which markedly affect soil hydraulic properties; moreover, land rehabilitation is an effective measure to restore the ecological function of impacted lands. To analyze the effects of land subsidence and rehabilitation on soil hydraulic properties, an underground coalmine in the Loess Plateau of China was selected to conduct a field plot experiment. Four plots were designed, including one unmined plot (UMP), two subsided plots (SPI and SPII) and one rehabilitated plot (RHP), and 16 sampling points were located in each plot. The bulk density (BD), soil moisture retention curve (SMRC), field capacity (FC), saturated hydraulic conductivity (Ks) and soil disintegration rate (SDR) at the depths of 0–20 cm, 20–40 cm, 40–60 cm and 60–80 cm at each sampling point were measured, and soil pore size distribution (PSD) based on SMRC was analyzed. The correlation analysis among soil hydraulic properties and the path analysis of effects of subsided cracks on the hydraulic properties were carried out in this study. Land subsidence increased the variability of soil hydraulic properties; whereas, they became relatively uniform after land rehabilitation. Land subsidence significantly altered soil hydraulic properties, increasing BD, Ks, SDR and soil micropores and decreasing FC; however, land rehabilitation can improve soil hydraulic properties and increase the use efficiency of soil water, decreasing BD, Ks, SDR and increasing FC and soil macropores. The cracks related to subsidence and vegetation had significant effects on soil hydraulic properties, especially BD; the crack width and vegetation coverage had a marked effect on BD.