摘要
据现有文献报导，除前寒武式系和第三系外，地史时期中白云岩δ＾１３Ｃ值主要分布在－５‰～＋５‰的范围。但是，作者在研究准噶尔盆地上二叠统芦草沟组白云岩碳位素时获得得了一批高富集＾１３Ｃ的资料，其中白云岩δ＾１３Ｃ布于７．３‰～１７．９‰，平均１１．７‰（７）；白云石δ＾１３Ｃ介于７．９‰～１６．１‰，平均１１．６‰（５）。根据区域地质、岩石学和矿物学资料，结合现代沉积剖面。
According to publications, the δ 13 C value of the dolostones mainly ranges from -5‰ to +5‰ in a geological history except the Precambrian and Tertiary. However, we obtained some data of the dolostones which are more enriched in 13 C than +5‰ when we researched the dolostones in the Upper Permian Lucaogou Formation. The δ 13 C value of the dolostones varies in the range from +7.3‰ to +17.9‰ with an average of +11.7‰(7) and that of the dolomites from +7.9‰ to +16.1‰, averag +11.6‰(5). Based on the data of regional geology, petrology, mineralogy of the Upper Lucaogou Formation, the carbon isotopic characteristics of CO 2 from modern sedimentary sections in oceans and lakes and the simulation of bacterial process and carbonate minerals in ancient sedimentary sections we analyzed the distribution characteristics of the dolostones and considered that except higher buried rate of the global Permian living things and higher salinity of the researched area the anomally 13 C-enriched dolosdones are mainly due to the formation of 13 C-depleted CH 4 and 13 C-enriched CO 2 caused by the carbon isotopic fractionation of organic matter during a bacterial process in a fermentation zone under an anaerobic condition. The more fully the process carried out, the more enriched in 13 C the CO 2 in the sedimentary medium was and the heavier the carbon isotope of the dolostones. Simutaneously only when this process continued could the 13 C-enriched dolostones interbeded with black shales be formed. This phenomenon indirectly indicates that there was a long continuous period of the bacterial process when the Upper Permian Lucaogou Formation sedimented so that considerable amounts of biogenic gas dorminated by mechane could be generated. Because the gas was formed earlier and was easy to diffuse, it was difficult for the gas to form gas pools and to be preserved till now, but as one of possible sources of natural gas attention should be paid to it.
出处
《沉积学报》
CAS
CSCD
北大核心
2000年第3期449-452,共4页
Acta Sedimentologica Sinica
关键词
白云岩
细菌作用
生物气
上二叠统
碳同位素
dolostones anormal 13 C enrichment bacterial process biogenic gas Upper Permian Jungar Basin
