摘要
秦岭造山带中分布于商丹和勉略缝合带之间的泥盆系,发育有众多Au、Ag和Pb-Zn矿床,长期以来备受关注。对于泥盆系物源和形成环境认识始终存在不同认识。砂岩碎屑组成、碎屑重矿物、地球化学成分、砾岩组成以及古水流研究表明,北秦岭是秦岭泥盆系的主要物源区,盆地基底隆起也是泥盆系重要物源区。砂岩碎屑组成、碎屑重矿物和砾岩组成表明,泥盆系物源区曾出露有岛弧火山岩、花岗岩、变质岩及少量沉积岩、超镁铁岩。砂岩地球化学成分和砂岩碎屑模式研究表明,秦岭造山带中泥盆系主要形成于活动大陆边缘,其碎屑沉积物来自多种构造环境中的岩石单元。
Devonian sediments in the Qinling orogen predominantly crop out between the Shandan and Mianlue sutures. Abundant Au, Ag and Pb-Zn deposits in the Devonian strata have attracted considerable interest since the late 1960s, but provenance and tectonic setting of these sediments are controversial. Sandstone detrital fragments, detrital heavy mineral assemblage, geochemistry of siltstone and mudstone, composition of conglomerate and paleocurrent data demonstrate that the North Qinling was the major source area of the Devonian sediments, and basement uplift should be another important source area. Detrital fragment and heavy mineral assemblage of sandstone and fragments of conglomerate indicate that arc-related igneous rocks, granitoids, metamorphic rocks and some sedimentary and ultramafic rocks should out crop in the source area. Geochemistry of siltstone/mudstone and detrital model of sandstones suggest that the Devonian sediments in the Qinling orogen mainly deposited in an active continental margin, and they derived from the rocks with different tectonic settings.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2007年第5期1023-1042,共20页
Acta Petrologica Sinica
基金
国家自然科学基金项目(40334044
40602026)
地质调查项目(1212010611807)共同资助
关键词
秦岭泥盆系
碎屑组成
重矿物
地球化学成分
源区
构造环境
Devonian system in the Qinling orogen, Detrital fragments, Heavy mineral assemblage, Geochemistry, Provenance, Tectonic setting
