A set of black shale deposited in the Early Cambrian and characterized by a large thickness and high organic matter content is one of the important exploration target strata for marine shale gas in South China.The sedimentary environment and enrichment mechanism of organic matters in the black shale are discussed based on the core and geochemical data from Well XYZ-1 drilled through the Early Cambrian Mufushan Formation in northern Jiansu area.The Mufushan Formation in Well XYZ-1 is a set of depositional sequence of black and dark gray carbonaceous shale with stone coal layers on top and at bottom and interbeds of thin-layered carbonate rocks.The average values of V/(Ni+V)

Ni/Co

U/Th

and V/Sc are 0.74

6.78

1.46

and 65.43

respectively.These ratios as indicators of redox environment suggest that the sediments were under anoxic conditions and two strong sulfidation events once occurred at the bottom and top.The average total organic carbon (TOC) content of the Mufushan carbonaceous shale is 5.62%

with the TOC value of 72.2% of the samples collected greater than 2%.The TOC-TS correlation coefficient is as high as 0.89.The hypoxic environment with sulfidation events provided favorable conditions for the enrichment and preservation of organic matters

thus laid down foundation for the development of high-quality source rocks and reservoirs in the Mufushan Formation of northern Jiansu.