Middle Ordovician multi-stage penecontemporaneous karstification in North China: Implications for reservoir genesis and sea level fluctuations

Palaeokarsts contain important information about subaerial exposures due to sea-level regression, which has been considered as a dominant genesis of reservoirs. Herein we describe a typical sedimentary core section of the Middle Ordovician Majiagou Formation that records multi-stage penecontemporaneous karstification in North China. Petrographic observations and stable isotopic data reveal high-frequency penecontemporaneous subaerial exposure...