An Early Ordovician fossil seamount of the Hongguleleng–Balkybey Ocean in the northern West Junggar terrane (NW China) and its implications for the ocean evolution

•A “typical” seamount rock assemblage is determined in the northern West Junggar terrane, NW China.•The fossil seamount formed in the Early Ordovician.•The seamount formed in an ocean intraplate environment and derived from a mantle plume source.