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Sediment Dynamics and Morphodynamics of River-Sea Sediment Dispersal Systems through Space and Time: A Source-to-Sink Perspective
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Source-to-Sink processes and environment variations in the East Siberia Sea since the last deglaciation
Tuesday 8th @ 1410-1430, Conference Room 1
Xuefa Shi* , 1 Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China
2 Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China Oceanography, State Oceanic Administration, Qingdao 266061, China
Limin Hu, 1 Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China
2 Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China
Jianjun Zou, 1 Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China
2 Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China
Shuqing Qiao, 1 Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China
2 Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China
Yangguang Liu, 1 Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, State Oceanic Administration, Qingdao 266061, China
2 Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266061, China
Anatolii Astakhov, V.I.Il'chev Pacific Oceanological Institute, Far East Branch of Russian Academy of Science, (FEB of RAS) Vladivostok, 690041, Russia
Presenter Email: xfshi@fio.org.cn |
The East Siberia Sea with one of the widest continental shelf in the world ocean has undergone dramatic changes in past environment, accompanied by diminished sea ice covers, increased river runoff, intensified melting of permafrost and strengthened coastal erosion. Here, we investigate both source-to-sink processes and environment changes in the East Siberia Sea since the last deglaciation on the basis of data and samples collected during the Sino-Russia Joint Expedition in 2016, in combination with published results.
Our results suggest that amounts of terrigenous material is delivered to the East Siberia Sea from river and coastal erosion. In particular, the old carbon associated with permafrost formed during ice ages is erodedand transported to the East Siberia Sea. On average, modern sedimentation rate is ~1.4mm/yr on the continental shelf of the East Siberia Sea, which is lower on the continental slope. Presently, the surface sediments mainly consist of fine-grained fraction on the East Siberia Sea shelf. Wave-induced sediment transport mainly occurs in coastal areas, whereas sea ice dominates the cross-shelf transport of sediments.
Exposed East Siberia Sea shelf during the last glacial sea-level lowstand was re-submerged with rising sea level since the last deglaciation. Subsequently, processes related to sediment deposition and biogeochemistry on the shelf are mainly controlled by both oceanic circulation and sea ice. In addition, the spatial distributions of sediments are also affected by coastal erosion with rising sea level besides the fluvial input. It is found that higher TOC input from the permafrost during the early Holocene than that of the last deglacial period , which is mainly related to rapid warming and enhanced coastal erosion.
Totally, The sedimentation rates varies greatly in space. The main factors controlling the sediment processes and environmental evolution changesduring the transition from the last deglaciation to the Holocene. Both rivers and sea level are dominated during the last deglacial interval, while sea ice became to play a more pronounced role during the Holocene and become a key factor linking land-ocean-atmosphere-biosphere interactions. |
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