Multi-stage formation of the Feragen ophiolite,Norway:Implication from petrology and geochemistry of peridotites and chromitites and its potential for prospecting  

作　　者：Tian Qiu Fa-hui Xiong David G.Gee Yuan Li Jing-sui Yang 

机构地区：[1]Center for Advanced Research on the Mantle(CARMA),Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China [2]Southern Marine Science and Engineering Guangdong Laboratory,Guangzhou 511458,China [3]Key Laboratory of Depositional Mineralization and Sedimentary Minerals,Shandong University of Science and Technology,Qingdao 266590,China [4]Orogen Dynamics Department of Earth Sciences Uppsala University Villavagen 16,Uppsala SE-75236,Sweden [5]School of Earth Sciences and Engineering,Nanjing University,Nanjing 210023,China

出　　处：《China Geology》2024年第4期686-701,共16页中国地质（英文）

基　　金：financially supported by the National Natural Science Foundation of China(92062215,41720104009,42172069);the China Geological Survey(DD20221886,DD20221817,DD20221657,DD20230340,DD20221630);the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0201);the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0801)。

摘　　要：The ultramafic massif of Feragen,which belongs to the eastern ophiolitic belt of Norway,has abundant amounts of chromite ores.Recent studies have revealed a complex melt evolution in a supra-subduction zone(SSZ)environment.This study presents new whole-rock major element,trace element,and platinum-group element chemistry to evaluate their petrogenesis and tectonic evolution.Harzburgites have high CaO,Al_(2)O_(3),TiO_(2),MgO,and REE contents corresponding to abyssal peridotites,whereas dunites have low CaO,Al_(2)O_(3),TiO_(2),MgO,and REE contents corresponding to SSZ peridotites.The Cr^(#)and TiO_(2) of chromian spinels in the harzburgites suggest as much as about 15%–20%melting and the dunites are more depleted with>40%melting.The harzburgites and the dunites and high-Cr chromitites represent,respectively,the products of low-degree partial melting in a back-arc setting,and the products of melt-rock interaction in a SSZ environment.The calculated fO_(2) values for dunites and high-Cr chromitites(-0.17–+0.23 and+2.78–+5.65,respectively and generally above the FMQ buffer)are also consistent with the interaction between back-arc ophiolites with oxidized boninitic melts in a SSZ setting.

关 键 词：GEOCHEMISTRY ƑO_(2) Platinum-group elements High-Cr podiform chromitites SSZ peridotite Harzburgites Feragen ophiolite Norway DUNITE Abyssal peridotite 

分 类 号：P618.31[天文地球—矿床学] P618.33[天文地球—地质学]