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导言铁建造,蒸发岩和磷灰岩是经济上有重要意义的化学沉积岩。该沉积岩沉积在经历过很长地质时代的盆地中。因为它们是化学沉淀,所以,它们必定反映出其形成的水体特征,我们小组试图确定生物圈的演变是否能根据这些沉积类型的地层记录来推断。富铁沉积岩可划分为两种广义的类別:铁岩,主要以显生宙的薄层出现;铁建造,一般呈燧石条带状,主要在前寒武纪形成,无疑代表沉积戍因的铁的最大富集。我们的注意力几乎完全集中在后一类岩石,把它看作水圈、大气圈和生物圈演化的潜在指标。
Introduction Iron construction, evaporites and phosphorites are economically important chemical sediments. The sediments are deposited in basins that have undergone a long geological period. Because they are chemically precipitated, they must reflect the water features they form, and our group is trying to determine if the evolution of the biosphere can be inferred from the stratigraphic records of these sedimentary types. The iron-rich sedimentary rocks can be divided into two broad categories: iron rocks, which occur mainly as thin layers of the Phanerozoic; iron, generally flint-banded, mainly formed during the Precambrian, undoubtedly representing the The largest iron enrichment. Our attention is almost entirely focused on the latter type of rock as a potential indicator of the evolution of the hydrosphere, the atmosphere and the biosphere.