The C isotopic ratios of organic carbon in the black shale are from –26 to –30 permil.Horizontal veins are often recognized in the clastic sediments, and are composed of quartz, calcite, sphalerite, pyrite, arsenopyrite, pyrrhotite and chalcopyrite. The C isotopic ratios of vein carbonates are from –4.6 to –5.2 permil.