藏北龙木错东部三岔口地区下奥陶统与泥盆系的不整合界面

在北羌塘三岔口一带采获丰富的腕足类:汉伯矮正形贝及比较种Nanorthiscf.hamburgensis(Walcott)。建立了早奥陶世岩石地层单位——三岔口组,是羌塘地区目前有化石控制的最低层位。中、晚泥盆世拉竹龙组与下伏志留系、奥陶系不整合接触关系的进一步确定,证明了羌北-昌都板块与扬子板块的亲缘性,为羌北-昌都板块属性的确定提供了重要证据。

Unconformity between the Lower Ordovician and Devonian in the Sanchakou area in the eastern part of the Lungmu Co, northern Tibet, China.

Abundant brachiopods (Nanorthis cf. hamburgensis (Walcott)) have been collected from the Sanchakou area, northern Qiangtang, and according to the fossils the authors erect a new Early Ordovician lithostratigraphic unit-Sanchakou Formation, which is the lowest horizon controlled by fossils in the Qiangtang region at present. The further determination of the unconformable contact relationships between the Middle-Late Devonian Lazhulong Formation and its underlying Silurian and Ordovician has prove the affinity between the northern Qiangtang-Qamdo plate and the Yangtze plate. This provides important evidence for the determination of the nature of the Qiangtang-Qamdo plate.