Yangjiaping

Northwestern Hunan

is situated in the west margin of Central Hubei carbonate platform.In the Cambrian

there occurred successively a series of catastrophic events in the study area

including oceanic anoxic event

turbidity event and tempest event.According to the petrological characterisitics of the black rock series and the facts that they occur on the bases of the rapid transgressional sequences and are distributed widely in South China and the whole world

the formation of the black rock series should be related to the meteorite impact

the break up of pancontinent and the eustatic sealevel abrupt rising between the Sinian and Cambrian.The turbidity events and tempest events were all strong local catastrophic events.The former resulted in phosphorous turbidites and calcareous turbidites

their induced factors were related to tempest activities;the latter resulted in near source tempestites and scoured basement autochthonous tempestites.