【摘要】 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。更多还原

【Abstract】 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.更多还原