摘要
以英国北威尔士和我国黔东湘西、新疆乌尔禾和塔里木的沥青为例,讨论了沥青的 Pb、Sr、Nd 同位素地球化学特征。结果表明:(1)沥青(前身物石油)的形成可能有多种途径,如壳源有机物生成(北威尔士、黔东湘西)和深源无机合成,后者的地质环境为地幔俯冲带(乌尔禾沥青)或下地壳麻粒岩相(塔里木);(2)沥青生成的时代比习惯认为的要古老得多。Pb、Sr、Nd 同位素还可给出原油运移、沥青沉淀的年龄。深入研究沥青的成因,对油气资源评价、勘探目标选择有重要意义。
Authors take the bitumen from North Whales in Britain,East Guizhou- West Hunan,Wu'erhe in Kelamayi oil field of Xingjiang and Tarim Basin for examples,describe Pb,Sr,Nd isotope geochemical features of the bitumen mentioned above.It is shown that concerning the origin of bitumen,there may be several ways.It may either evolve from organic matter in earth's crust,the bitumen from North Whales,East Guizhou -West Hunan as examples,or come from inorganic synthesis in deep source with a geological setting either of subducting mantle zone such as Wu'erhe bitumen,or of lower crust granulite facies such as Tarim bitumen.The time of bitumen-generating is often much older than it is used to be considered.The Pb,Sr and Nd isotopes also tell the time of oil migration and bitumen precipitation.It is considered that further study on the origin of bitumen may have great significance in assessment of oiL/gas resource and choice of the goals.
出处
《海相油气地质》
1997年第4期53-57,共5页
Marine Origin Petroleum Geology
