70 Ma以来风尘活动在太平洋铁锰结壳中的记录

开展风尘沉积研究对于了解源区气候变化和大气循环过程具有重要意义。利用高分辨率电子探针技术，通过对铁锰结壳中风尘指示因子（Al沉积通量）的年际变化研究，探讨低纬度铁锰结壳中风尘沉积特征。结果显示：在过去近70 Ma中，低纬度铁锰结壳Al沉积通量平均值为300.5  μg/(cm^2·ka)，并且记录了南、北半球的不完整风尘史。在晚白垩世－晚中新世期间，M06铁锰结壳位于热带辐合带之南，受南半球风系影响，其Al沉积通量大小反映了环太平洋区域火山活动强度；晚中新世后，受北半球风系控制，M06铁锰结壳Al通量的变化反映了亚洲风尘源区构造和气候的变化。

Records of Past 70 Ma Dust Activities in Ferromanganese Crusts from Pacific Ocean

The eolian deposition is one useful index to know the climate change of source region and the atmospheric cycle model at that time.The eolian records indicated by Al fluxes in the low-latitude ferromanganese crusts are determined by the high-revolution microprobe technique.The results show that the average content of Al fluxes in the ferromanganese crusts during the past 70 Ma is 300.5 μg/(cm2·ka),which has recorded the incompleteness of eolian history in the southern hemisphere and the northern hemisphere.From the Late Cretaceous to the Late Miocene period,the M06 ferromanganese crust lay in the southern of the intertropical convergence zone,and its’ Al fluxes recorded the eolian deposition from the episodic volcanism in the southern hemisphere.Since the Late Miocene period,the M06 has been controlled by the wind system of the northern hemisphere,and its’ Al fluxes can reflect the change of tectonic and climate in Asian dust source area.