东海外陆架晚更新世沉积物中的有用重矿物及其资源潜力

对东海外陆架中部表层沉积物34个样品，南部两个岩心75个样品的沉积物特征和重矿物特征进行了分析，计算了其中有用重矿物砂的品位。东海外陆架晚更新世残留沉积中有用的重矿物砂来源于中国大陆，其含量与细砂含量、重矿物总量、沉积物的粒度和分选性呈正相关关系。重矿物砂赋存在海退层位中，形成于滨岸带，并经过后期海侵过程的改造和进一步富集，主要分布在水深100～200 m范围内。外陆架中部有用重矿物砂高品位异常区面积达1.2×10.4 km锆石和石榴石品位达到Ⅰ级异常。南部岩心中异常品位的有用重矿物砂的厚度1.5～2 m，锆石品位达到工业边界品位，研究区钛铁矿普遍出现Ⅱ级和Ⅱ级以上的异常品位。东海外陆架区浅海砂矿成矿条件较好，具有较大的资源潜力，值得进一步调查研究。

Valuable heavy minerals and their resource potential on outer shelf in East China Sea during the Late Pleistocene

Thirty four samples were collected from surface sediments on outer shelf of the middle East China Sea，and 75 samples were collected from two cores of outer shelf of the southern East China SeaThe characteristics of sediments and heavy minerals of these samples have been studied，and grades of valuable heavy minerals in these samples are calculatedThe results show that valuable heavy minerals in relict sediments from the outer shelf of the East China Sea during the Late Pleistocene were derived from the continent of ChinaThe content of valuable heavy minerals is closely related to the content of fine sand and the total heavy minerals，grain size and sorting of the sedimentsHeavy minerals occured in regressivesequence in the littoral zone，and had been reworked and enriched by late transgressive processThey are mostly distributed between 100 m and 200 m of water depthThe high grade valuable heavy minerals cover an area of about 1.2×10.4 kmThe grades of zircon and garnet have reached the order Ⅰanomaly of marineplacer，and the thicknessof valuable heavy minerals bearing sand in southern cores range from 1.5 to 2 metersZircon has met boundary grade(≥0.5 kg/m)，and the grade of ilmeniteis commonly up to order Ⅱ and above order Ⅱ anomaly in the study areaThe conditions to form marine placer on the outer shelf are favorableThe placer resourceis considered to have a good economic potential and it is worth further investigation on the outer shelf of the East China Sea，especially along southern outer shelf