The Chuanlinggou Formation(ca 17 Ga)is characterized by dark shale and is widespread in the North China Platform， with a thickness up to 900 m. In this formation abundant centimeterscaled pygmatic sandveins are well developed. They have been interpreted as deriving from the sand filled fissures created by biogenic gas release. In the sandveins minor amounts of authigenic carbonate precipitation(ACP)and pyrites have been identified . The ACP is mainly of crypto-to microcrystalline dolomites， occurring either as horizontally continuous seams or as discrete spots， often accompanied with organicrich lamina. The ACP seams generally occur at the places where biofilms densely concentrated， and tend to extend along the biofilms. In contrast, the ACP spots prefer to exist in intergrain pores as cryptocrystalline cements or along the outer margins of sandveins as microcrystalline dolomites. These two types of ACP have been recognized both in the sandveins and host sediments. The associated  framboidal pyrites are more abundant in mud sediments. while rimmed pyrite crystals in the sandveins. Siderite crystals also exist in the sandveins. These minerals are often associated with ACP forming characteristic fabrics， along with the organicrich shale and well developed microbially induced sedimentary structures(MISS)， suggesting an anoxic environment for the Chuanlinggou deposition. Analyses of the morphology and rheology of the sandveins and their distribution in relation to the dark shale suggest that they were derived from the fissures created by gas release as passages and subsequently filled by stormtransported sands. The gas release origin is also supported by the existence of gas blisters(MISS)on sedimentary surfaces. The coexistence of ACP and authigenic pyrites and their preferential occurrence in the sandveins indicate that they resulted from the anaerobic oxidation of methane(AOM)and bacterial sulfate reduction(BSR)happened in a sulfatemethane transition zone(SMTZ)few centimeters below the sedimentary surface. The recognition of putative microbial fossils in the sandveins and the biomarkers indicative of archaea and sulfur bacteria from the dark shale may also provide evidence for AOM. Methane might derive from anaerobic degradation of buried organic matter， with part from the possible methanogenesis as well. The recognition of ACP and AOM in the Chuanlinggou Formation is of significant implications for the Mesoproterozoic plaeoclimate and paleoceanographic analyses. With a low seawater sulfate concentration and therefore a shallow SMTZ during the Mesoproterozoic ocean， the consumption of methane by AOM would be proportionally lower than that in the modern marine environments. As a result， the methane fluxed into the atmosphere would inevitably increase the relative importance of methane in maintaining the Mesoproterozoic greenhouse climate.