PROVENANCE RESPONSE OF DETRITAL MINERALS FROM MEDIUM AND SMALL RIVERS IN OFFSHORE SOUTHERN SHANDONG PENINSULA

106 surface sediment samples from the coastal waters off the southern Shandong Peninsula plus 94 samples from the Dagu, Wulong and Rushan Rivers are collected and analyzed for detrital minerals. The distribution pattern and provenances of the detrital minerals are systematically studied and a total of 40 heavy minerals and 13 light minerals recognized. Heavy minerals are dominated by hornblende, epidote, biotite and authigenic pyrite, whereas light minerals consist mainly of quartz, plagioclase, potassium feldspar and weathered mica. There are four mineral zones in the study area. The Zone Ⅰ is the offshore area from Jiaozhou Bay mouth to Lushantou. The Zone Ⅱ may be further divided into 2 sub-areas. The Zone Ⅱ₁ is a shallow water area near the T-Shaped Bay and Aoshan Bay about 15 m deep. The Ⅱ₂ is far in the southeast of the study area in a water depth of more than 20 m. The Zone Ⅲ is in the transitional zone between Zone Ⅱ and Ⅳ. The Zone Ⅳ is the coastal water in the southwestern part of Rushankou. The mineral assemblage of Zone I and Zone Ⅱ is commonly consisting of hornblende, epidote, quartz and feldspar. The Zone Ⅰ and the Sub-zone Ⅱ₁ are greatly affected by the materials from the Dagu, Wulong and Rushan Rivers, as well as the coastal bedrock and island weathering debris. The Sub-zone Ⅱ₂ is mainly covered by the shelf relict sediments deposited during the Late Pleistocene low sea level. The mineral assemblage in the Zone Ⅲ is dominated by hornblende, quartz, feldspar and flaky minerals. The mineral assemblage in the Zone Ⅳ is dominated by flaky minerals, authigenic pyrite, hornblende and quartz. The material sources of the Zones Ⅲ and Ⅳ are diverse, and the Yellow River contributes significantly.