Silt is a kind of unconsolidated sediment consisting of fine particles;silt is generally deposited across wide areas on the surfaces of drainages and in oceans under static or slow-hydrodynamic conditions. The organic...Silt is a kind of unconsolidated sediment consisting of fine particles;silt is generally deposited across wide areas on the surfaces of drainages and in oceans under static or slow-hydrodynamic conditions. The organic carbon(OC) in silt has multiple essential environmental functions. This paper elaborates the morphological and environmental indication functions of OC in silt, and the effect of its own migration and transformation on environmental deterioration. Organic carbon exists in silt in two forms, free and mineral-binding. Meanwhile, based on its formation and structure, OC can be divided into light and heavy fraction of OC. Environmental information including data related to paleoclimates, ancient levels of productivity level, and variations in regional organism abundance can be discovered from total organic carbon, the C/N ratio, and OC isotope content. Degradation of OC is believed to participate in the emission of greenhouse gases, release of heavy metals and other contaminants. Finally, from the view of silt deposition, the possible influence of complex water-rock interaction in which OC is involved during the evolution of silt to a clayey aquitard on the hydrochemical composition of groundwater is discussed, which provides a new perspective for future research on the carbon cycle in nature.展开更多
基金jointly supported by the National Natural Science Foundation of China (Nos. 41630318 and 41521001)Research Program for Geological Processes+1 种基金Resources and Environment in the Yangtze River Basin (No. CUGCJ1702)the China Geological Survey Project (Nos. 2019040022,DD20190263)。
文摘Silt is a kind of unconsolidated sediment consisting of fine particles;silt is generally deposited across wide areas on the surfaces of drainages and in oceans under static or slow-hydrodynamic conditions. The organic carbon(OC) in silt has multiple essential environmental functions. This paper elaborates the morphological and environmental indication functions of OC in silt, and the effect of its own migration and transformation on environmental deterioration. Organic carbon exists in silt in two forms, free and mineral-binding. Meanwhile, based on its formation and structure, OC can be divided into light and heavy fraction of OC. Environmental information including data related to paleoclimates, ancient levels of productivity level, and variations in regional organism abundance can be discovered from total organic carbon, the C/N ratio, and OC isotope content. Degradation of OC is believed to participate in the emission of greenhouse gases, release of heavy metals and other contaminants. Finally, from the view of silt deposition, the possible influence of complex water-rock interaction in which OC is involved during the evolution of silt to a clayey aquitard on the hydrochemical composition of groundwater is discussed, which provides a new perspective for future research on the carbon cycle in nature.
