地质论评2026，Vol.72Issue(5)：1479-1493,15.DOI:10.16509/j.georeview.2026.01.002
西藏狮泉河—纳木错蛇绿混杂岩带中东段舍所硅质岩地球化学特征及其沉积环境
Geochemical characteristics and sedimentary environment of Shesuo siliceous rocks in the middle—east segment of the Shiquanhe—Nam Lake ophiolitic mélange zone,Xizang(Tibet)
摘要
Abstract
Objectives:The Shesuo ophiolitic mélange is located in the middle—east segment of the Shiquanhe—Nam Lake(Nam Co)ophiolitic mélange zone,Xizang(Tibet).In order to clarify the petrogenesis,sedimentary environment and understand its geological significance of the siliceous rocks in the Shesuo ophilitic mélange.Furthermore,attempt to explore the tectonic attributes of the Shiquanhe—Nam Lake ophiolitic mélange zone. Methods:In this paper,research on the siliceous rocks from the Shesuo ophiolitic mélange,including field work,petrology,as well as major-and trace-element analysis.Moreover,the petrogenesis and sedimentary environments of these siliceous rocks have also been discussed. Results:The Shesuo siliceous rocks are exposed on the top of basalt,is purplish red or red color.The Shesuo siliceous rocks consist of three types:rich radiolarian siliceous rocks,interbedded radiolarian siliceous rocks,and rare radiolarian siliceous rocks.The geochemical characteristics of the rich radiolarian siliceous rocks reveal that they were biogenic siliceous rocks deposited at the continental magin which more farther from mainland in the subduction and reduction stage of the oceanic plate.interbedded radiolarian siliceous rock show that they were biogenic siliceous rock affected by the mid-oceanic ridge marginal hydrothermal plume,and were deposited in the oceanic basin.Rare radiolarian siliceous rocks reveal that it was hydrothermal siliceous rocks mey be deposited in the marginal area of the mid-oceanic ridge,far from the central rift valley.These siliceous rocks should have been deposited in different stages during the late Jurassic to early Cretaceous with the expansion of the oceanic crust.The subsequent geological structural activities such as the shortening of the Lhasa terrane,and the Qinghai—Xizang(Tibet)Plateau continuous uplift lead to the Shesuo siliceous rocks exposure within a limited area at present. Conclusions:Based on the research result of the Shiquanhe—Nam Lake ophiolitic mélange zone,in this paper,we speculated that the Shesuo Meso-Tethy Ocean which located at the middle—east segment of the Shiquanhe—Nam Lake Meso-Tethys Ocean was already has complete mid-oceanic ridge—oceanic basin—continental margin system,and the oceanic basin was mature and expansive relatively.It may be indicated that the Shiquanhe—Nam Lake Meso-Tethys Ocean was an independent and new fromed ocean that emerged slightly later than the Bangongco—Nujiang Meso-Tethys Ocean.关键词
硅质岩/狮泉河/纳木错/蛇绿混杂岩带/地球化学特征/沉积环境/西藏Key words
siliceous rock/Shiquanhe/Nam Lake/ophiolitic mélange zone/geochemical characteristics/sedimentary environment/Xizang(Tibet)引用本文复制引用
张诗启,王建科,贺承广,翟文建,黄丹峰..西藏狮泉河—纳木错蛇绿混杂岩带中东段舍所硅质岩地球化学特征及其沉积环境[J].地质论评,2026,72(5):1479-1493,15.基金项目
本文为中国地质调查局项目(编号:1212011020000150005-07)和河南省地质研究院科研项目(编号:2024-909-XM05、XM04)的成果. This work was supported by the China Geological Survy Foundation(No.1212011020000150005-07) （编号:1212011020000150005-07）
the Henan Academy of Geology Foundation(Nos.2024-909-XM05,2024-909-XM04) （Nos.2024-909-XM05,2024-909-XM04）
