1)Combustible organic deposits often coexist with soda saline-alkalai soil

drab soil and sajong black soil.All these kind of carbonate-rich soils are called carbonate-soils in this paper.2)Large amount of CO

2

is emitted during the formation of the combusti-ble organic deposits.As confirmed by regional mapping

the landscape of gas-bearing soils in Song-Nen Basin

as well as the concentration of soda there in soils are related in some extent to the gas of Daqing Oilfield.3)Having determind the background value of carbonates in soils of a se-dimentary basin and contoured its abnormal zones

can one roughly point out the organic carbon-rich areas beneath the soils.There are three carbonate-soil zones in China

which involved partially the nine big oil-bearing sedimentary basins and drab soil zones.Numerous combustible organic deposits could be found in these three large carbonate-soil zones.