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在生物地层控制下,对塔里木盆地柯坪地区乌什鹰山剖面和柯坪水泥厂剖面的寒武-奥陶系界线附近地层进行了连续的、密集的同位素采样.样品碳同位素测定结果表明,这两条剖面寒武-奥陶系界线附近碳同位素组成以负δ13C值为主.其中,乌什鹰山剖面碳同位素的演化趋势表现为交替出现的4次负漂移和4次正漂移,柯坪水泥厂剖面表现为交替出现的5次负漂移和5次正漂移.在生物地层框架下,可以将这两条剖面的碳同位素演化趋势与国际上重要的寒武-奥陶系界线剖面(1)中国大阳岔剖面、(2)加拿大Green Point剖面、(3)澳大利亚Black mountain剖面以及(4)美国Lawson Cove剖面进行良好的比对.基于碳同位素演化趋势的对比结果,确定了乌什鹰山剖面和柯坪水泥厂剖面的寒武-奥陶系界线,对界线附近的地层进行了细分和对比.
Under the control of biostratigraphy, the continuous and intensive isotope sampling of the strata near the Cambrian-Ordovician boundary in the Wushiying Mountain section of the Keping area in the Tarim Basin and the Cambrian Cement Plant section was carried out. The results of the carbon isotope determination of the samples show that, The δ13C value of carbon isotope composition near the Cambrian-Ordovician boundary between these two profiles is dominant, in which the evolution trend of carbon isotopes in the section of Wushan Mountain shows alternating 4 negative and 4 positive drift, The section of Ping Cement Plant shows alternately five negative excursions and five positive excursions.Under the framework of biostratigraphy, the carbon isotopic evolution trend of these two sections can be compared with the internationally important Cambrian-Ordovician boundary line ( 1) a good alignment of the Dayangcha profile in China, (2) the Green Point profile in Canada, (3) the Black mountain profile in Australia and (4) the Lawson Cove profile in the United States.Based on the comparison of carbon isotopic evolutionary trends, Yingshan section and the Cambrian Cement Plant section Cambrian - Ordovician boundary line, stratigraphy near the boundary were subdivided and compared.