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藏北羌塘沃若山地区三叠系肖茶卡组之上不整合沉积超覆了一套沉火山碎屑岩夹火山岩地层,该套地层底部的玻屑凝灰岩夹层的SHRIMP锆石U-Pb年龄为(216.1±4.5)Ma,该年龄代表了沃若山地区晚三叠世火山-沉积事件的时代,它与最近获得的羌塘盆地广泛分布的那底岗日、石水河等地区的那底岗日组火山岩的形成时代基本一致,同属晚三叠世.微量元素及同位素地球化学特征表明,沃若山地区火山岩的地球化学特征与其相邻的那底岗日、石水河等地区的那底岗日组火山岩十分相似,表明该时期羌塘地区的火山岩可能具有相同的岩浆源区和相似的构造环境.羌塘盆地晚三叠世大规模火山喷发与火山-沉积事件的正确认识,对于探讨东特提斯域晚三叠世生物绝灭、气候变化与海退事件具有重要的意义,同时,对于了解晚三叠世-侏罗纪北羌塘地区新一轮盆地演化的开启时间、盆地性质及沉积特征也具有重要的意义.
Unconformity sedimentation over the Triassic Xiaochaka Formation in the Woluo Mountain area, northern Qiangtang, overrides a set of Shenlao clastic rock volcanic strata. The SHRIMP zircon U-Pb ages of the vitrinite tuff intercalations at the bottom of the set of formations (216.1 ± 4.5) Ma, which represents the age of the Late Triassic volcanic-sedimentary events in the Woluo Mountain area. It is closely related to the recently obtained areas such as Nabigangri and Shishuihe, which are widely distributed in the Qiangtang Basin The volcanic rocks in the Kongri Formation are basically the same in age and belong to the Late Triassic.The trace element and isotopic geochemical characteristics show that the geochemical characteristics of volcanic rocks in the Woluo Mountain area are similar to those of the adjacent basal day, The volcanic rocks of Kongri Group are very similar, indicating that the volcanic rocks in the Qiangtang area may have the same magma source zone and similar tectonic setting during this period. Correct understanding of the Late Triassic volcanic eruption and volcanic-sedimentary events in the Qiangtang Basin is of great significance. Late Triassic biological extinction, climate change and retreat in the Tethys area are of great significance. At the same time, it is of great significance to know the opening time of the Late Triassic-Jurassic North Qiangtang basin in a new round of basin evolution, The nature and deposition characteristics are also of great significance.