Re-Os同位素是近年来发展起来的一种新的同位素技术,既可用于定年又能用于示踪。国际上如何对沉积岩进行精确定年一直是个难题。近年来的研究表明,Re-Os同位素可以用于黑色页岩的精确定年,同时可用于示踪古海洋环境。笔者对华南下寒武统牛蹄塘组黑色页岩开展了Re-OS同位素定年研究,获得的等时线年龄为537±10Ma。
As one of the recently-developed new geochemical techniques, the Re-Os isotope system can not only serve the precise dating but also provide information on environmental changes. The organism-rich black shales are very suitable for Re-Os dating, and hence precise ages can be obtained. In South China, several periods of oceanic anoxic events occurred from Neoprotercrozoic to Cambrian, resulting in the deposition of huge thickness of black shales. Using the Re-Os isotope method, we can not only estimate the time of such events, but also effectively trace the paleo-oceanic environment. The results obtained by the authors show that the black shales of Lower Cambrian Niutitang Formation yield a Re-Os isochron age of 537 ± 10 Ma.