岩石矿物学杂志2025，Vol.44Issue(3)：573-586,14.DOI:10.20086/j.cnki.yskw.2025.4185
西准噶尔白碱滩红山梁组硅质岩的地球化学特征、成因及形成构造环境
Geochemical characteristics,genesis and tectonic setting of the siliceous rocks from Hongshanliang Formation in Baijiantan,Western Junggar
摘要
Abstract
The red siliceous rocks of the Late Devonian Hongshanliang Formation in the Baogutu tectonic belt,Western Junggar,are extensively developed,comprising approximately 80％of the total stratigraphic thickness.Studying its geochemical characteristics can reveal the genesis of the rock and indicate the tectonic environment,and provide new sedimentary information for the study of the Late Devonian tectonic paleogeographic evolution in the area.The upper siliceous rocks are predominantly red to reddish-brown,with poorly developed bedding,and mainly occur in massive or banded forms.They are often associated with volcanic lava or within volcanic rock inter-layers,but no sponge spicules have been observed.The middle siliceous rocks are red,display thin-bedded struc-tures with well-developed stratification,and frequently exhibit sedimentary lamination with abundant sponge spic-ules.These rocks are interbedded with tuffaceous siltstone and tuffaceous argillaceous siltstone.The lower siliceous rocks,which are red or gray,show transitional lithological and petrographic features between the two aforemen-tioned types.The upper and lower siliceous rocks are relatively low in SiO2(71.90％,87.48％),CaO(1.45％,1.28％),P2O5(0.09％,0.06％)and δEu,and high in TiO2(0.57％,0.2％),Al2O3(13.47％,5.54％),MgO(1.80％,0.94％),Na2O(3.93％,0.64％),K2O(2.05％,1.14％),Na2O/K2O(1.35,0.40),Al2O3/(Al2O3+TFe2O3)(0.74,0.71)and Sc,V,Cr,Cu,Zn,Sr,Y,Zr,La,Ce,Nd,Yb,Lu,ΣREE,Th/Sc,Th/U.The content and corresponding ratio of the major elements in the siliceous rocks in the middle are just the opposite,with high SiO2(91％),CaO(2.14％),P2O5(0.48％),low TiO2(0.07％),Al2O3(1.05％),MgO(0.32％),Na2O(0.14％),K2O(0.14％),Al2O3/(Al2O3+TFe2O3)(0.37),and significantly depleted in Sc,V,Cr and other elements that are relatively enriched in magmatism.The correlation ratios and graphic analysis show that the volcanism in Hongshanliang Formation had experienced a strong→weak→ strong changing process from bottom to top.The upper and lower siliceous rocks are mainly volcanogenic silicon,which are formed in the back-arc basin margin area near the arc volcano,while the middle siliceous rocks are mainly biogenic,which are formed in the back-arc basin environment during the volcanic dormancy period.关键词
硅质岩/地球化学/岩石成因/构造环境/红山梁组/西准噶尔Key words
siliceous rock/geochemistry/petrogenesis/tectonic setting/Hongshanliang Formation/Western Junggar分类
地质学引用本文复制引用
王韬,李永军,李海,付浩,郑孟林,黄家瑄,韩杨,徐淼..西准噶尔白碱滩红山梁组硅质岩的地球化学特征、成因及形成构造环境[J].岩石矿物学杂志,2025,44(3):573-586,14.基金项目
国家科技重大专项(2017ZX05008-006-003-001) （2017ZX05008-006-003-001）
国家重点研发计划(2018YFC060400) The National Science and Technology Major Project(2017ZX05008-006-003-001) （2018YFC060400）
The National Key Research and Development Program of China(2018YFC060400) （2018YFC060400）
