• 责任者：Feng Caixia (State Key Laboratory of Ore Deposit Geochemistry ; Institute of Geochemistry ; Chinese Academy of Sciences ; Guiyang 550002 ; China)
• 刊名：Mineral Deposits
• 出版年：2011
• 卷期：30(5)
• 关键词：硅质岩 ; silicolite ; 岩石地球化学 ; lithogeochemistry ; 沉积环境 ; sedimentary environment ; 青藏高原 ; Qinghai-Tibetan Plateau
• 页码：p.773-786
• 图表：9 illus., 4 tables, 60 refs.
• 分类号：0803
• 出版序号：1689
• issnNo：ISSN0258-7106
• isbnNo：CN11-1965/P

style="MARGIN: 0cm 0cm 0pt" class=MsoNormal>///The Bangong Co-Nujiang suture zone is the second huge ultramafic rock belt in Tibet. Based on detailed geochemical research, this paper discusses the genesis and tectonic setting of siliceous rocks in Gerze area, Tibet. Some conclusions have been reached:&nbsp; 1)&nbsp;the w(SiO₂) content range is 85.23%style="FONT-FAMILY: 宋体; mso-ascii-font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～93.73%, and Si/Al ratios vary in the range of 34.08style="FONT-FAMILY: 宋体; mso-ascii-font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～56.92, indicating that they contain a relatively high proportion of terrigenous muddy sediments; 2)&nbsp;Incompatible elements such as Hf, Pb, Nb, Ta, Th and U are obviously depleted; 3)&nbsp;Al/(Fe+Mn+Al) ratios are 0.41style="FONT-FAMILY: 宋体; mso-ascii-font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～0.69, suggesting bio-genesis. Ba/Sr and U/Th ratios are lower than 1, and Al-Fe-Mn triangular diagram and Zr-Cr diagram show non-hydrothermal characteristics of siliceous rocks; 4)&nbsp;Al₂O₃/(Al₂O₃+Fe₂O₃) ratios are 0.50style="FONT-FAMILY: 宋体; mso-ascii-font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～0.77, and chondrite-normalized as well as North American shale-normalized REE patterns show that siliceous rocks are enriched with LREE with weak positive Ce anomaly and no obvious Ce anomalies; (La/Ce)_SN, Ce/Ce^* and(La/Lu)_SN values are 1.11style="FONT-FAMILY: 宋体; mso-ascii-font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～1.17, 0.90style="FONT-FAMILY: 宋体; mso-ascii-font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～0.92 and 1.10style="FONT-FAMILY: 宋体; mso-ascii-font-family: ’Times New Roman’; mso-hansi-font-family: ’Times New Roman’">～1.62, V<23 μg/g, and V/Y<2.8; and 5)&nbsp;Si and O isotopes indicate typical characteristics of radiolarian chert.style="mso-bidi-font-weight: normal">style="COLOR: black; FONT-SIZE: 14pt" lang=EN-US>space prefix = o ns = "urn:schemas-microsoft-com:office:office" />