Spatial Distribution and Provenance of Detrital Minerals of Surface Sediment in the Okhotsk Sea

Kunshan Wang,Sergey Alexandrovich Gorbarenko,Xuefa Shi,Zhengquan Yao,Jianjun Zou,Yanguang Liu

doi:10.3389/feart.2021.636850

Abstract

The Okhotsk Sea is a distinctive marginal sea in the northwestern Pacific Ocean, which is characterized by the prevalence of seasonal sea ice in winter. Sediment is sourced from the around region through sea ice transportation, rivers input, and volcanic eruptions. Surface sediments of the Okhotsk Sea shelf vary greatly in grain size, and the sand content is generally high, which is conducive to source-to-sink studies using ice-rafted detritus (IRD),detrital minerals and single mineral geochemistry methods. In this paper, the 63–125 μm grain size fraction was selected for the detrital minerals analysis of surface sediments (top 0–10 cm) from 58 sediment stations and 15 stations samples has been chosen for garnet chemistry. These stations are mainly located in the south central Okhotsk Sea. The distribution and composition of the heavy minerals are influenced by material derived from the Amur River, the north shelf (Okhotsk-Chukotka volcanic belt), Sakhalin Island, the Kamchatka Peninsula, and the Kuril Islands. The detrital mineral results show that hornblende, epidote and garnet are terrigenous material indicators. High contents of fresh hypersthene can be used as an indicator of volcanic eruption materials. And high content of abraded hypersthene can be used as an indicator of Okhotsk-Chukotka volcanic materials. In the northern Okhotsk Sea, the southward moving sea ice produced in Sakhalin Bay collides with the sea ice produced off the east coast of Sakhalin Island, which causes the sea ice to accumulate to the southeast. This results in the deposited ice-rafted debris having a southeastward facing fan shape, and the geochemical analysis of the garnet supports this conclusion. From west to east, the amount of material from Sakhalin Island gradually decreases, while the amount of material from the Amur River and Chukchi-Kamchatka increases.

Highlights

Heavy mineral analysis methods are usually used to interpret the provenance, transport pathways, and geochemistry of sediments, especially in source-to-sink studies (Sevastjanova et al, 2012; Nicholson et al, 2013)
The second reason is that the material inputs are derived from different areas, i.e., in the Sakhalin Bay, sediment is dominated by river input; on the northern shelf of the Okhotsk Sea, sediment is dominated by volcanic debris and coastal erosion materials transported by sea ice; and off the west coast of the Kamchatka Peninsula and around the Kuril Islands, sediment is dominant by volcanic detrital material
Based on the mineral assemblages and the garnet geochemistry, the sediments off the eastern coast of Sakhalin Island were mainly transported by sea ice

Summary

Introduction

Heavy mineral analysis methods are usually used to interpret the provenance, transport pathways, and geochemistry of sediments, especially in source-to-sink studies (Sevastjanova et al, 2012; Nicholson et al, 2013). Heavy Minerals in Okhotsk Sea analysis methods are often used in studies of the source of fine sands, especially on shelves where river input of heavy minerals can provide abundant information about the sediment source, sedimentary environment, and hydrodynamic conditions (Zhang et al, 2015; Wang et al, 2019). Cores with more sediment analysis indicators, including geochemistry, IRD, and detrital minerals, are mainly located in the south central Okhotsk Sea [e.g., cores PC-7R, LV28-40 (42 and 44), and OS03-1] (Gorbarenko et al, 2007, 2010, 2014; Nürnberg et al, 2011; Zou et al, 2015). Fewer studies have been conducted on the sediment cores from the northern shelf of the Okhotsk Sea (Gorbarenko et al, 2007)

Results

Discussion

Conclusion