Gang Li

Bio: Gang Li is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Provenance & Geology. The author has an hindex of 10, co-authored 22 publications receiving 316 citations. Previous affiliations of Gang Li include Ministry of Land and Resources of the People's Republic of China & Nanjing University.

Distribution, source and pollution level of heavy metals in river sediments from South China

Abstract: The sediment pollution caused by heavy metals has attracted a great deal of attention due to its persistence, bioaccumulation and toxicity. This research was the first to consider the whole of South China to obtain an overall profile of heavy metal spatial distribution, possible sources and pollution levels in river systems. For these data, 14 selected heavy metals were analysed in river sediments collected from sampling sites in Guangdong, Fujian, Guangxi and Hainan Provinces. The geoaccumulation index and enrichment factor revealed that river systems in South China were universally contaminated by Cd, As and Sn, which might be distributed by anthropogenic activities. Moreover, Guangdong Province, a relatively developed area in South China, was relatively polluted by certain heavy metals such as Ni, Cu, Zn and Mn. Multivariate statistical analyses such as Pearson's correlation matrix and a principal component analysis determined that several of the heavy metals might be derived from similar anthropogenic activities such as industrial effluents and domestic sewage discharge. In terms of heavy metal contamination in South China, necessary measures should be undertaken to protect rivers in South China.

The Quaternary Lancaster Sound trough‐mouth fan, NW Baffin Bay

Abstract: The development of the Lancaster Sound Trough Mouth Fan (TMF) and glacial history in Arctic Canada were studied using a high-resolution seismic profile across the entire fan and two piston cores. Stacked tills separated by erosion surfaces on the shelf pass seaward through till deltas into thick transparent glacigenic debris flow (GDF) deposits on the slope, separated by thin, well-stratified glaciomarine layers. An age model was built by ties to the Ocean Drilling Program Site 645. The deepest GDF on the seismic profile was indicative of the onset of shelf-crossing glaciation in the Early Pleistocene. The transition of the growth of Lancaster Sound TMF from an aggradational sequence (unit M) to an aggradational–progradational sequence (unit F) occurred at the Middle Pleistocene transition in glacial cyclicity. In the most recent glacial cycle, GDF sheets were deposited during Heinrich events 4 and 2 according to the correlation of the main detrital carbonate beds in two piston cores. The outmost till wedge reflects the maximum advance of the grounding glacier, far seaward of previously proposed Last Glacial Maximum ice extent. Copyright © 2011 John Wiley & Sons, Ltd.

Bottom water hydrodynamic provinces and transport patterns of the northern South China Sea: Evidence from grain size of the terrigenous sediments

Abstract: Sediment transport in the source-to-sink systems of the northern South China Sea (SCS) has been of increasing interest during the past few decades. However, the mechanisms for sediment redistribution remain unclear. Sources and transport patterns in the northern SCS were investigated in this study based on grain size analyses of 205 surface sediment samples. Detailed characterizations of hydrodynamic conditions and sediment transport have been made using the log-ratio method to partition grain size components of surface sediments in the northern SCS. Results reveal that sediment dispersal patterns in the region generally contain traction, saltation, graded and uniform suspension modes. Based on the spatial distribution characteristics, the study area can be classified into three hydrodynamic provinces. Province A contains high traction concentrations that are exposed to the longshore current and topographic features, which are distributed in the Taiwan Shoal, Dongsha Islands and extends from the Pearl River estuary to the southeast of Hainan Island. Province B is characterized by higher values of saltation and graded suspension, which are widespread along the northern slope of the SCS, and its formation is interpreted as the result of interactions between down- and along-slope processes. Province C reaches its greatest concentration in the abyssal areas, particularly in the vicinity of Luzon Island, which settles only under calm conditions. Combined with previous data concerning magnetic susceptibility distributions of surface sediments from the northern SCS, the sediment transport route near the mainland is traced. Furthermore, based on distribution pattern of sortable silts and hydrodynamic provenance of the terrigenous sediments, the sediment transport route in the deep water region of the northern SCS is outlined. It flows along marginal channels which cut across the continental slope along isobaths. Taken together, the combination of grain-size components and sortable silts of surface sediment used here is a promising tool to better assess the modern variability of hydrodynamic conditions and transport processes in marine environments.

Rare earth elements:A review of applications, occurrence, exploration, analysis, recycling, and environmental impact

Abstract: Rare earth elements (REE) include the lanthanide series elements (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) plus Sc and Y. Currently these metals have become very critical to several modern technologies ranging from cell phones and televisions to LED light bulbs and wind turbines. This article summarizes the occurrence of these metals in the Earth's crust, their mineralogy, different types of deposits both on land and oceans from the standpoint of the new data with more examples from the Indian subcontinent. In addition to their utility to understand the formation of the major Earth reservoirs, multi-faceted updates on the applications of REE in agriculture and medicine including new emerging ones are presented. Environmental hazards including human health issues due to REE mining and large-scale dumping of e-waste containing significant concentrations of REE are summarized. New strategies for the future supply of REE including recent developments in the extraction of REE from coal fired ash and recycling from e-waste are presented. Recent developments in individual REE separation technologies in both metallurgical and recycling operations have been highlighted. An outline of the analytical methods for their precise and accurate determinations required in all these studies, such as, X-ray fluorescence spectrometry (XRF), laser induced breakdown spectroscopy (LIBS), instrumental neutron activation analysis (INAA), inductively coupled plasma optical emission spectrometry (ICP-OES), glow discharge mass spectrometry (GD-MS), inductively coupled plasma mass spectrometry (including ICP-MS, ICP-TOF-MS, HR-ICP-MS with laser ablation as well as solution nebulization) and other instrumental techniques, in different types of materials are presented.

Dusty plasma effects in Saturn's magnetosphere

Abstract: [1] Comets, planetary rings, exposed dusty surfaces, and the zodiacal dust cloud are all examples of environments where dusty plasma effects establish the size and spatial distributions of small grains. Simultaneously, dust often influences the composition, density, and temperature of the plasma surrounding it. The dynamics of charged dust particles can be surprisingly complex and fundamentally different from the well-understood limits of gravitationally dominated motions of neutral particles or the adiabatic motion of electrons and ions in electromagnetic fields that dominate gravity. In this review we focus on observations that are best explained by theories concerning dusty plasma effects at Saturn. In addition to presenting our current models we also discuss our expectations for new discoveries based on existing observations at Jupiter or on purely theoretical considerations. Our intent is to give an up-to-date overview of dusty plasma effects in Saturn's magnetosphere and to draw attention to several outstanding problems that could be resolved by the Cassini mission.