摘要
对大连湾近海表层沉积物进行了重矿物的分离和鉴定,探讨该区沉积物中重矿物来源,并对沉积环境及其主控因素进行了分析。研究区沉积物中普遍出现的碎屑重矿物共有29种,其中普通角闪石含量最高,绿帘石和钛铁矿次之。重矿物特征指数及不稳定矿物/稳定矿物比值被用来协助划分矿物组合区,结合重矿物分布特征,研究区可划分为3个矿物组合区,对应3个沉积环境区。近岸浅水区,物质来源单一,动力分选是控制重矿物分布的首要因素,重矿物主要来源于辽东半岛的沿岸冲刷;中部台地及二级岸坡之上,属于相对静水环境区,重矿物分布的主控因素是长途搬运过程中的分选作用,主要是研究区东部海域物质经过较远的距离搬运而来;南部深水区,重矿物分布受到物源、搬运距离以及水动力条件等多重因素的影响,而且源区含有较多稳定矿物,可能与周边海域较强潮流带动下沉积物的再悬浮有关。
The heavy mineral assemblages and their distribution pattern of the subsurface sediments of the Dalian Bay were preliminarily discussed in this paper in connection with their sources and depositional environments as well as dominant factors. A total of 29 species of heavy mineral were discovered in the study area, dominated by hornblende and followed by epidote and ilmenite. Using heavy mineral characteristic indexes （ATi, GZi, ZTR and UM/SM）, and the ratio of stable and unstable mineral as means, we divided the study area into 3 subregions, corresponding to 3 sedimentary environments. In the subregion of shal low water in the north, where dynamic sorting dominated, sediments were mainly derived from the coastal erosion of the Liaodong Peninsula. In the subregion of Central platform, where hydrodynamics was weak and differentiation dominated the distribution of heavy minerals, sediments were from the east of the study area through a long distance of transportation. In the subregion of deep water in the south, where the dis tribution of heavy minerals were affected by a multiple factors, including source, differentiation and sedi mentary environment, the deposition of sediments was supposed to be related to the sediment resuspension driven by strong tidal current.
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2011年第6期13-20,共8页
Marine Geology & Quaternary Geology
基金
我国近海海洋综合调查与评价(908-01-CJ03
908-02-03-08)
国家自然科学基金项目(41076032)
关键词
重矿物
物质来源
沉积环境
大连湾
heavy mineral provenance
sedimentary environment
the Dalian Bay
