Whole Rock Geochemistry of the Ultramafic and Lower Banded Series of the Stillwater Complex,Montana:Preliminary Interpretations
New whole rock data on the rocks of the Ultramafic and Lower Banded Series of the Stillwater Complex combined with data from the chill rocks suggests that the composition of the rocks essentially reflects that of their cumulate phases and that they contain ~10 % trapped liquid fraction.The Ultramafic Series rocks and in particular the chromite layers contain an excess of platinum-group elements relative to the trapped liquid fraction,which might suggest the presence of cumulate sulfides.However,the S content of the rocks is too low for cumulate sulfides to be present.Possibly S has been removed from the rocks as suggested by the low S/Se ratios.The reef samples show similar incompatible trace element contents to the rocks underlying and overlying the reef suggesting that they too contain ~10 % trapped liquid fraction.The reef rocks show no additional signs of continental crust contamination e.g Th or LREE enrichment.The JM reef is enriched in Pd relative to Pt with Pd/Pt ratio of 3 greater than that of the chills.We suggest this is due to leaching of Pd from the footwall to reef.
S.-J.Barnes Philippe Pagé
Sciences de la Terre,Université du Québec á Chicoutimi,Chicoutimi,G7H 2B1,Canada
国际会议
贵阳
英文
85-88
2012-06-16（万方平台首次上网日期，不代表论文的发表时间）