• 责任者：Sun Lixin (Tianjin Center of Geological Survey ; CGS ; Tianjin 300170 ; China) ; Ren Bangfang
• 刊名：Geological Bulletin of China
• 出版年：2013
• 卷期：32(2/3)
• 关键词：花岗质片麻岩 ; granitic gneiss ; 铀—铅计时 ; U-Pb dating ; 内蒙古 ; Inner Mongolia
• 页码：p.341-352
• 图表：illus., 4 tables, 33 refs.
• 分类号：0802
• issnNo：ISSN1671-2552
• isbnNo：CN11-4648/P

Augen and banded gneisses of the Xinhuadukou Group occur in the Hanjiayuanzi area of northern Daxinganling, NE China, which were previously attributed to be the lower meta-strata of Xinghua Formation, Xinhuadukou Group. However, our studies indicate that these augen and banded gneisses are actually deformed granites （orthogneisses）. SHRIMP zircon U-Pb dating yields an ^207Pb/^206Pb age of 1837Ma±5Ma, interpreted to be the crystallization age of the granitic gneisses. LA-ICP-MS zircon U-Pb dating yields an ^20 Pb/^206Ppb age of 1741Ma±30Ma and 1854Ma±20Ma, interpreted to be the crystallization age of the granitic gneisses. Zircon Hfanalyses from 21TW29-2 show that the granitic gneisse have negative and variable εHf（t） values between -3.9 and - 8.5, with Mesoarchean （2.78-3.01Ga） crustal model ages which suggests that the magma of the granitic gneisses were mainly derived from an old Mesoarchean crustal source. The discovery of the Paleoproterozoic granites in the studied area suggests that an early Precambrian metamorphic basement exists in the Eerguna massif.