摘要
对华北克拉通南缘豫西燕山期具类似于板块俯冲带花岗岩成分变化规律（成分极性）的八宝山、柳关、后瑶峪花岗斑岩类的Pb、Sr、Nd同位素地球化学特征的研究,揭示了这些斑岩的主要物质来源是新太古代的太华群斜长角闪岩部分熔融产生的熔浆与地幔来源物质混合形成的产物。稀土元素含量非常低的八宝山花岗斑岩在岩石形成过程中有流体与其发生交代作用,由于交代及混合作用造成花岗斑岩类的Rb—Sr等时线多为假等时线;柳关花岗斑岩基本上完全由太华群的斜长角闪岩提供物质,豫西地区燕山期的花岗岩岩基其物质来源更为复杂,可能有宽坪群为其提供物质。
The Yanshanian granite-porphyries in the Lushi district exhibit a regular compositional va-riation from the Babaoshan stock in the south, the Liuguan stock in the intermediate area to the Houyaoyu stock in the north.The composition variation is very similar to the composition polarity shown by are-type granites, as well as the Early Paleozoic granites of are-type in the North Qinling Belt. Their Pb, Sr and Nd isotopic characteristics reveal that the major source material of the granite - porphyies was a mixture of a melt produced by partial melting of the amphitolite of the Archean Taihua Group with a small proportion of basaltic magma originated from the upper mantle. The Babaoshan granite - porphyry with very low REE contents infers that the rock suffered hydrothermal metasomatism which resulted in pseudoisochron of Rb -Sr isotopic system of the porphyry. The Liuguan granite-porphyry originated from almost single source rock- the amphilolite of Taihua Group. The Yanshanian granite from the Erlangping batholith in the North Qinling Belt should have a more compli-cated source rock in the light of its Pb, Sr and Nd isotopic features. The rocks of the Kuanping Group might provide material for the granitic magma.
出处
《地球科学（中国地质大学学报）》
EI
CSCD
北大核心
1994年第3期375-382,共8页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金
地质行业科学发展基金(No.48970171)
国家自然科学基金(No.9192200l)联合资助
关键词
花岗岩
同位素示踪
地球化学
granite-porphyry
isotopic tracing
compositional polarity
source of granitic magma.
