黄海全新世泥质体表层沉积物重矿物特征及其指示意义

Characteristics and Significance of Heavy Minerals in the Surface Sediments of the Holocene Mud of the Yellow Sea

基于对黄海56个表层沉积物样品的碎屑重矿物和粒度分析,研究了黄海全新世泥质体底质表层沉积物的重矿物特征及其指示的物源和环境信息。结果表明:泥质体重矿物含量低且组成变化大,矿物组合主要为普通角闪石-不透明矿物-片状矿物-绿帘石-自生黄铁矿,泥质体可分为三个矿物区:泥质体北部矿物区(Ⅰ区)、山东半岛沿岸矿物区(Ⅱ区)和泥质体南部矿物区(Ⅲ区),泥质体之外西南侧分布着南黄海西部矿物区(Ⅳ区)和南黄海南部矿物区(Ⅴ区)。Ⅰ区和Ⅱ区明显受黄河物质控制,Ⅲ区物源较为复杂,除黄河物质外,东海北部陆架和长江物质也对其产生一定影响。自生黄铁矿的富集指示了冷水团的存在和弱还原的沉积环境;多种矿物的含量分布指示了切变锋的存在,其"水障"作用对泥质体的空间分布和矿物组成造成了很大影响,对沉积物的运移趋势也具有显著限制作用。

Based on the analysis of detrital heavy minerals and grain size of 56 surface sediments in the Yellow Sea,the author researched the heavy minerals characteristics,source and environmental information of the surface sediments in the Holocene mud of the Yellow Sea.The results show that the heavy minerals of the Holocene mud have low content and huge variation,and the mineral assemblage is common hornblende,opaque mineral,schistose mineral,epidote,authigenic pyrite.The Holocene mud is divided into three regions:northern mineral area of mud(DistrictⅠ),the coastal mineral area of Shandong Peninsula(DistrictⅡ)and southern mineral area of mud(DistrictⅢ).In addition,there are the western mineral area of South Yellow Sea(DistrictⅣ)and the southern mineral area of South Yellow Sea(DistrictⅤ)in the southwest side of the Holocene mud.District I andⅡare obviously controlled by the Yellow River,but the provenance of the districtⅢis complex.Besides the Yellow River,the northern continental shelf of the East China Sea and the Yangtze River affect the districtⅢas well.The enrichment of authigenic pyrite indicates the existence of cold water mass and the weak reductive sedimentary environment.Many content distribution of minerals reflect the existence of shear front whose“water barrier”function affects the distribution of Holocene mud and the composition of minerals deeply.Furthermore,it has obvious limit on transport trend of sediment.