Spatial variation in grain-size population of surface sediments from northern Bering Sea and western Arctic Ocean: Implications for provenance and depositional mechanisms
at : Aug 03, 2020 16:23:17  (view:103)

Spatial variation in grain-size population of surface sediments from northern Bering Sea and western Arctic Ocean: Implications for provenance and depositional mechanisms

Weiguo WANG1*, Jichao YANG2, Mengwei ZHAO3, Linsen DONG4, Min JIANG1, Erhui HUANG1

1Third Institute of Oceanography, Ministry of Natural Resources, P.R.C., Xiamen 361005, China;

2 National Deep Sea Center, Ministry of Natural Resources, P.R.C., Qingdao 266237, China;

3 Pilot National Laboratory for Marine Science and Technology, Qingdao 266237, China;

4 First Institute of Oceanography, Ministry of Natural Resources, P.R.C., Qingdao 266061, China

Corresponding author, E-mail: wangweiguo@tio.org.cn

Abstract:  In general, sediments in nature comprise populations of various diameters. Accurate information regarding the sources and depositional mechanisms of the populations can be obtained through their temporal and spatial comparisons. In this study, the grain size distribution of surface sediments from the Bering Sea and western Arctic Ocean were fitted and partitioned into populations using a log-normal distribution function. The spatial variations in the populations indicate differences in their sources and deposition mechanisms. The sediments on most of the Bering Sea Shelf originated from the Yukon River, and were transported westward by waves and currents. However, the presence of a coarser population outside Anadyr Bay was the result of Anadyr River transport. Additionally, a northward transport trend of fine suspended particles was observed on the west side of the Bering Sea Shelf. The sediments in Hope Valley in the south Chukchi Sea also originated from the Yukon River. The coarser population on the central Chukchi Sea Shelf originated from the east of Alaska, not the Yukon River, and was transported by sea ice and bottom brine water. The populations of sediments from the Chukchi Basin and the base of the Chukchi Sea Slope are the result of sea ice and eddy action. Surface sediments from the western high Arctic Ocean predominantly comprised five populations, and two unique populations with mode diameters of 50–90 µm and 200–400 µm, respectively, were ubiquitous in the glacial and interglacial sediments. It was difficult to distinguish whether these two populations originated from sea ice or icebergs. Therefore, caution should be exercised when using either the > 63 µm or > 250 µm fractions in sediments as a proxy index for iceberg and ice sheet variation in the high Arctic Ocean.

Keywords: Bering Sea, western Arctic Ocean, surface sediments, grain-size population, provenance, depositional mechanisms