Provenance and tectonic setting ofmiddle-upper Devonian sandstones in the Qinling Orogen (Shanyang area): New insights from geochemistry, heavy minerals and tourmaline chemistry
Provenance and tectonic setting ofmiddle-upper Devonian sandstones in the Qinling Orogen (Shanyang area): New insights from geochemistry, heavy minerals and tourmaline chemistry
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秦岭造山带（山阳地区）中上泥盆统砂岩物源及构造环境：地球化学、重矿物和电气石化学的新认识
DOI：
10.1016/j.tecto.2016.09.023
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发表时间：
2016
期刊：
影响因子：
2.9
通讯作者：
Song Guangzeng
中科院分区：
文献类型：
--
作者：
Shi guanzhong;Wang Hua;Huang Chuanyan;Yang Shuiyuan;Song Guangzeng
山阳地区泥盆系砂岩出露于秦岭造山带南部。地球化学分析表明，砂岩中富Zr，Th/U和Rb/Sr比值高，表明砂岩曾经历过多次再循环。主要重矿物为锆石、电气石、磷灰石、金红石和金红石，次要矿物为尖晶石、辉石、钛铁矿和磁铁矿。碎屑电气石颗粒的矿物组成表明，碱性组分亚群占主导地位，电气石的主要矿物种类为黑云母和镁电气石。电气石成分环境判别图解表明，约70%的颗粒与变细晶岩、变砂岩和钙硅酸盐来源一致，约30%的颗粒来自花岗岩类和伴生伟晶岩和细晶岩。秦岭杂岩区的变质岩和花岗质岩石是潜在的物源。地球化学、重矿物和矿物化学的综合数据表明，泥盆纪砂岩在前陆盆地环境中广泛再生，而不是在被动大陆边缘。
Devonian sandstones in the Shanyang area crop out in the southern part of the Qinling Orogenic Belt. Geochemical.analyses showthat the sandstones are enriched in Zr and have high Th/U and Rb/Sr ratios indicating the sandstones.underwent repeated recycling. Zircon, tourmaline, apatite, rutile and anatase are the predominant heavy.minerals while minor minerals include spinel, pyroxene, ilmenite and magnetite. The mineral compositions of.detrital tourmaline grains indicate that the alkali compositional subgroup dominates; schorl and dravite are.the main tourmaline species. A tourmaline composition environment discrimination diagram shows that about.70% grains are consistent with metapelite, metapsammite, and calc-silicates sources and about 30% of grains.are from granitoids and associated pegmatites, and aplites. Metamorphic and granitic rocks in the Qinling Complex.area are potential provenance. Overall data from geochemistry, heavy minerals and tourmaline chemistry.suggests the Devonian sandstones were extensively recycled in a foreland basin setting rather than at a passive.continental margin.