The Criteria on Maturity of Organic Materials in Carbonate Rocks by Ion Microprobe

Key words: 
• organic materials /
• maturity /
• SIMS

Abstract: he secondary ions of the hydrocarbon fragments suchas CH, CH₃ and benzene series homologues,etc. can be detected by ion microprobe(SIM S) in the organic analysis of carbonate rocks. There is a close relationship of the peak and its abundance of these fragment ions with the themical com posi do nand molecular structure of the organic materials detected. There is certain regularity with the change ofCH/C and CH₃ /C ratios which could reach the maximum at theoil forming period. And the value of themethyl ratio between arene compounds and benzene serial homologues can reflect the cha ng a of o rganicmatuity and shown good linear relationship vitrinite reflectance(R).This paper represented part of theexperimental results obtained during the study of the oil and soure rock correlation and oil-gas evolutionof marine carbonate rocks in the Yunnan, Guizhou and Guangxi area by using SIM S.