Pebbles in radiolarian cherts from the Lower Jurassic in the Kamusite area at the northeastern margin of the Junggar basin, Xinjiang, China and the radiolarian fauna therein

The Kelamaili orogenic belt, located on the northeastern margin of the Junggar basin, is an important tectonic unit in the Central Asian tectonic framework. Divergent views have long existed as to its evolutionary history though much study has been conducted. This paper reports the pebbles of purplish red radiolarian cherts in the Lower Jurassic Sangonghe Formation in the Kamusite area, northern Xinjiang, and radiolarian fauna therein. The latest radiolarians are early Visean in age. It is inferred thus that the Kelamaili oceanic basin closed in the late Early Carboniferous and that the Kelamaili orogenic belt was uplifted rapidly during the Early Jurassic.