胶东地区蓬莱群沉积岩碎屑锆石年龄和物源

Detritai Zircon Ages and Sources of Sedimentary Rocks in Penglai Formation, Eastern Shandong

分布于鲁东胶北地区蓬莱群为一套浅变质沉积岩，角度不整合覆盖在太古宙胶东群、元古宙粉子山群上。关于蓬莱群的沉积时代尚存较大的争议，认为是震旦纪或古生代沉积形成的。蓬莱群和五莲杂岩、北淮阳变质岩带都是位于大别-苏鲁超高压变质造山带北部的重要岩石构造单元。本文报道蓬莱群沉积岩碎屑锆石年龄和铪同位素分析资料，并探讨其可能的物质来源。

This paper reports ^207Pb/^206Pb ages and Hf isotopic composition of detrital zircons from sedimentary rocks of Penglai Formarion exposed in the northern part of the Sulu orogenic belt. Ages of fifty zircon grains obtained by the evaporation method mostly range from ca. 1 000 Ma to 1 800 Ma, clustering around 1 200 Ma and 1 600 Ma. Model ages of Hf isotopes range from about 1 300 Ma to 3 200 Ma, clustering around 1 700 Ma. The data of zircon ages and Hf isotopic composition imply that the sedimentary rocks were derived from sources of South China affinitv and probably deoosited between 1 000 Ma and 800 Ma.