• 责任者：San Feixue (Graduate School ; China University of Geosciences ; Wuhan 430074 ; China) ; Ling Wenli
• 刊名：Geochimica
• 出版年：2013
• 卷期：42(5)
• 关键词：闪长岩 ; diorites ; 风化作用 ; weathering ; 湖北 ; Hubei Province
• 页码：p.430-446
• 图表：13 illus., 8 tables, 38 refs.
• 分类号：0100
• issnNo：ISSN0379-1726
• isbnNo：CN44-1398/P

     As the important period of supergene elements＇ geochemistry circulation, rock weathering has important connection with the survival and the living environment of mankind. It is ideal to study the migration behaviors of elements under the surface condition in the eastern Three Gorge, located in Yichang, Hubei. This paper reports element and Sr-Nd isotopic geochemistry profiles of weathered Huangling dioritic rock mass in eastern Three Gorges. The samples were collected from three profiles, and their element mobility and Sr-Nd isotopic system stability are discussed. It demonstrates that （1） Ti is the ideal reference element for calculating element activity and indicating weathering characters; （2） CIA and CIW value increases from bedrock （D） to the top weathered layer （A）; the order of major elements activity is Na, Ca 〉 Si, P 〉 Mg, K 〉 A1 〉 Fe, Mn, Ti; （3） For trace elements, Zr, Hf, Sc, V, Y and REE are relatively stable, whereas chalcophile elements Cu, Mo and Zn are varied indistinctively and Pb is enriched. Variations of Sr, Ba and Rb are different in different profiles; （4） LREE of profile 1 and 2 is relatively enriched, whereas LREE of profile 3 is relatively depleted; the rising trends of δEu and δCe from bedrock to top weathered layers indicate preferential alteration and loss of Eu-enriched plagioclase, high oxygen fugacity resulting in transition of Ce^3＋ to Ce^4＋ and alteration and loss of soluble complex duringweathering; （5） the rising trend of initial Sr isotope ratios with increasing weathering and the involvement of extra high radiogenic Sr indicates that the Rb-Sr isotope system is an open system during weathering of dioritic rocks.The decrease of initial Nd isotope ratios with increasing weathering indicates the involvement of extra low radiogenic Nd; compared with their bedrocks, the weathering layers show wider ranges of εsr and εnd values with overall decreasing εnd. However, relatively the constant Nd isotopic model ages within error likely reflect the characteritics of bedrocks.