Cover Story：Oil seepage in the foreland of Yumu Mountain, Gansu Province. Field geological survey and structural mapping revealed the large-scale thrust and nappe system, right-lateral strike-slip faulting, and strike-slip related duplex in the Yumu Mountain area, northern Qilian Mountains. Structural analysis of shallow levels of deep seismic reflection and magnetotelluric (MT) sounding profiles validate the existence of thrust-nappe system with the Yumu Mountain as the klippe. Structural relationship analysis shows that the major Yumu Mountain nappe was formed approximately in the early period of Early Cretaceous, which reflects a strong tectonic compression in the late Mesozoic before the Cenozoic Indian-Asian collision. The discovery of oil seepages in the footwall Early Cretaceous strata underneath the Yumu Mountain nappe expands promising oil and gas prospects in this area. The research achievement led by Professor CHEN Xuan-hua obtained the honor of one of the excellent sci-tech achievements of the Chinese Academy of Geological Sciences in 2018. For details, see pp. 377-392 of this issue. (Photo by CHEN Xuan-hua)
