锶同位素地层学研究进展

PROGRESS IN STRONTIUM ISOTOPE STRATIGRAPHY

锶同位素地层学 (SIS)根据地质历史中的任何时间全球范围内海水的锶同位素组成都是均一的、海水 87Sr/86Sr比值随时间变化这一基本原理 ,利用代表原始海水的海相碳酸盐 (以及磷酸盐和硫酸盐 )的 87Sr/86Sr比值确定海相地层的年代 ,研究海平面变化、造山运动、古气候等全球事件 ,在地层学、沉积学、石油地质学和矿床学等领域中有着广泛的应用前景。锶同位素地层学已在世界范围内得到地质学家的普遍关注 ,并已获得迅速的发展 ,国内的有关研究则刚刚起步。锶同位素地层学研究的难点主要在于对样品成岩蚀变的控制和分析技术上 ,同时还需要有良好的地层学研究基础 ,在样品选择上应充分考虑其原始组分的抗成岩蚀变能力。锶同位素地层学的研究需要地层学家、沉积学家和地球化学家的共同努力。

Strontium isotope stratigraphy relies on the fundamental principle that the marine strontium is isotopically homogenous world wide at any time and the 87 Sr/ 86 Sr ratio of strontium in seawater of geological history has varied through time. By means of the 87 Sr/ 86 Sr ratio of marine carbonate (also phosphate and sulphate) which should record the original composition of sea water, we can date the marine sediments, research global events, such as history of basin subside, sea level change,orogenic events and palaeoclimate variation. The applied expectation of strontium isotope stratigraphy would be very extensive on stratigraphy, sedimentology, petroleum geology and economic geology, which has attained considerable development internationally. However strontium isotope stratigraphy is still in its infancy in China. The focus of strontium isotope stratigraphy is the influence of diagenesis and technology of measurement of 87 Sr / 86 Sr ratio. Meantime, strontium isotope stratigraphy also needs the support of stratigraphy. The ability of anti alteration of diagenesis of the original component of sample for strontium isotope stratigraphy is very important. The development of strontium isotope stratigraphy needs a great effort from stratigraphers, sedimentologists and geochemists, together.