• 责任者：Yuan Yajuan (Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Xia Bin
• 刊名：Geochimica
• 出版年：2013
• 卷期：42(5)
• 关键词：变质岩 ; metamorphic rocks ; 铀—铅计时 ; U-Pb dating ; 元素地球化学 ; elements geochemistry ; 江苏 ; Jiangsu Province
• 页码：p.499-506
• 图表：6 illus., 2 tables, 25 refs.
• 分类号：0802
• issnNo：ISSN0379-1726
• isbnNo：CN44-1398/P

     The low-grade metamorphic rocks in Shiqiao area are characterized by alkali-rich （Na2O＋K2O= 6.39%-10.65%）, high K20 （Na2O/K2O =0.03-0.05） and low Na20. They are further characterized by enrichment in 1 Rb, Ba, Th, Pb and U and depletion in Sr. The concentration of rare earth elements （REE） is in the range 130.89-232.80 μg/g. These rocks are enriched in light REE （LREE/HREE = 7.92-14.84） and lack of obvious Eu negative anomaly （δEu = 0.73-0.91）. The new shells of metamorphic composite zircon range in age from Proterozoic era （2483 Ma, 2370 Ma, 2211 Ma and 778 Ma） to Paleozoic era （544 Ma）. However, the existence of Paleozoic-age indicates the low-grade metamorphic rock within Shiqiao area belongs to the early Paleozoic （554 Ma）. The U-Pb ages of inherited zircons are concentrated at Mesoarchean, Neoarchean, Paleo-proterozoic. The different age within the news shells of metamorphic composite zircon shows that the inherited zircons were subjected to metamorphism in the source area. As the preceding feature are different from the paragneiss within Dabie-Sulu ultrahigh pressure metamorphic belt, the petrogenesis of the low grade metamorphic rock is a klippe.