Ce anomaly in minerals of eclogite and garnet pyroxenite from Dabie-Sulu ultrahigh pressure metamorphic belt:Tacking subducted sediment formed under oxidizing conditions  

作　　者：Deltlef Günther 

机构地区：[1]Institute of Inorganic Chemistry,ETHZürich,Universitatsstrasse6,CH-092Zürich,Switzerland

出　　处：《Science China Earth Sciences》2004年第10期920-930,共11页中国科学（地球科学英文版）

基　　金：co-supported by the National Natural Science Foundation of China(Grant No.40133020);the Chinese Ministry of Science and Technology(Grant No.G1999043202).

摘　　要：In-situ excimer laser ICP-MS analysis of minerals of eclogites and garnet pyrox- enites from type localities (Shuanghe, Maowu, Bixiling, and Yangkou) in the Dabie-Sulu ultra- high-pressure metamorphic belt reveals highly variable Ce anomalies from negative to positive in garnet. Similar Ce anomalies are also present in omphacite or clinopyroxene but to a much lesser extent. Such mixed negative and positive Ce anomalies mimic those found in severe weathering profiles developed under oxidizing conditions. They suggest the presence of sub- ducted sediment components in the eclogites and garnet pyroxenites, which in turn points to the potential importance of the recycled sediments in modification of the mantle composition during the deep subduction of the continental crust.In-situ excimer laser ICP-MS analysis of minerals of eclogites and garnet pyrox-enites from type localities (Shuanghe, Maowu, Bixiling, and Yangkou) in the Dabie-Sulu ultra-high-pressure metamorphic belt reveals highly variable Ce anomalies from negative to positive in garnet. Similar Ce anomalies are also present in omphacite or clinopyroxene but to a much lesser extent. Such mixed negative and positive Ce anomalies mimic those found in severe weathering profiles developed under oxidizing conditions. They suggest the presence of subducted sediment components in the eclogites and garnet pyroxenites, which in turn points to the potential importance of the recycled sediments in modification of the mantle composition during the deep subduction of the continental crust.

关 键 词：Dabie-Sulu  eclogite  GARNET pyroxenite  LA-ICP-MS  subducted sediment  Ce anomaly. 

分 类 号：P618.92[天文地球—矿床学]