【摘要】 通过对3块中太平洋铁锰结壳样品进行的生物地层学及其结构构造、元素地球化学剖面的综合研究发现,铁锰结壳的生长主要集中于两个形成环境存在差异分别由不同因素控制的形成阶段,一个是约25Ma以来其形成环境氧化程度由南极底层流(AABW)控制的对应于结壳新壳层的生长幕,另一个是渐新世之前其形成环境氧化程度由环赤道表中层洋流和高密度温盐表层水下沉控制的对应于结壳老壳层的生长幕,而在早、中渐新世处于两种环境的转换期,也正好是海退期、大洋低生产力期、低CCD和生物碳酸盐低产率期,形成结壳生长的主要生长间断。该研究成果对于进一步了解太平洋的古海洋、古环境演变有一定意义。更多还原

【Abstract】 [HJ*2/5]By the synthesis study for three central Pacific ferromanganese crusts (hereinafter for short as crusts) of their biostratigraphy, structure and element geochemistry on the section along their growth directions, it was found that the formation of the crusts concentrate on two different formation stages which were controlled by the different factors. The first formation stage which corresponds to the new layers of these crusts is the stage whose degree of oxidation of their ore-forming environment after about 25Ma obviously controlled by the Antarctic bottom water (AABW), and the other formation stage which corresponds to the old layers of these crusts is the stage whose degree of oxidation of their ore-formingenvironment before Oligocene controlled by surface and middle-level ocean currents which surrounds the earth’s equator and the sinkage of high density warm saline surface water, and in early and middle Oligocene the ore-forming environment belonged to their turnaround time of those two stages, which was also a period of marine regression, low oceanic primary productivity, low CCD and low production of the biogenetic carbonate, the crusts’ main growth hiatus occurred. This research finding is significance to the further study of the Pacific paleoceanography and its palaeoenvironment.更多还原