南极半岛西北部海域表层沉积物碎屑矿物研究

本文通过对南极半岛西北部海域23个表层沉积物中碎屑矿物分析研究,获得以下结果:1.主要矿物有单斜辉石、斜方辉石、角闪石、绿帘石、磁铁矿、钛铁矿、黄铁矿、白云母、黑云母、绿泥石、橄榄石,玄武闪石、石榴石、磷灰石、锆石、金红石及火山玻璃、斜长石、石英等;2.根据矿物分布特征和稀土元素特征本区可分为三个矿物区和三种矿物组合类型:①基性火山碎屑矿物沉积区,矿物组合类型为辉石-火山玻屑型;②中酸性火成矿物沉积区,矿物组合类型为辉石-绿帘石-角闪石-石英;③基性火山碎屑矿物和变质矿物混合沉积区。矿物组合类型为辉石-绿帘石-石榴石-石英-火山玻屑。

A STUDY ON CLASTIC MINERALS OF SURFACE SEDIMENTS IN THE SEA AREA NORTHWEST OF THE ANTARCTIC PENINSULA

Clastic minerals of surface sediments recovered from 23 stations in the sea area northwest of the Antarctic Peninsula were analysed to determine the composition and distribution pattern of the minerals and their sources. This study focused on the clastic minerals of 0.063-0.125 mm size fraction. The average content of heavy minerals in the sediments is 7.3%. The minerals are mainly chinopyroxene, orthopyroxene, hornblende, epidote, magnetite, ilmenite, pyrite, muscovitc, biotite, chlorite, olivine, oxyhorn-blende, garnet, zircon, apatite, rutite, volcanic glass, plagioclase, quartz, etc. Analysis and study were also made for traceclements and rareearth elements of the heavy sand minerals. These minerals are divided into three mineral associations according to their distribution pattern, i.e. (1) pyroxene-volcanic glass, (2) pyroxene-epidote-hornblende, and (3) pyroxene-epidotc-garnet associations, The minerals in this area are also localized in three zones, i.e. (1) the zone dominantly with basic volcanic clastic minerals, which is primarily located at surrounding sea off the south Shetland islands. (2) the zone dominantly with mid-acidie pyroclastic minerals, located at the western adjacent sea off the Antarctic peninsula and Bellingshausen sea. and (3) the zone with mixed the basic-volcanic clastic and metamorphic minerals, located at the eastern part off the south Shetland islands. Environment of the sedimentation were briefly discussed based on mineral investigation.