论文部分内容阅读
基于中国中部的一个沉积序列的铝浓度重建了过去6.0~2.0 Ma的大气铁载荷与粉尘通量变化。铁载荷从6.0 Ma的~0.3μg·m~(-3)开始增加,到3.0 Ma左右达到最高值约1.2μg·m~(-3),然后开始迅速下降。黄土高原的大气铁载荷和粉尘通量变化型式与ODP 885/886孔的粉尘通量,以及ODP 882孔的生物蛋白石海洋沉积速率的变化型式一致,都显示了从6.0 Ma到2.7 Ma的增加趋势。这表明粉尘的海气交换最可能通过铁肥机制影响海洋生产力。从3.6 Ma至2.7 Ma,铁载荷与北太平洋古海洋生产力及全球大气CO_2的变化存在高度一致性,指示了粉尘/铁通量的增加及其导致的各种反馈作用很可能加速北半球大冰期的发生。
Atmospheric iron load and dust flux over the past 6.0-2.0 Ma were reconstructed based on the aluminum concentration of a sedimentary sequence in central China. The iron loading increased from -0.3 μg · m -3 at 6.0 Ma and reached a maximum of about 1.2 μg · m -3 at about 3.0 Ma, then began to drop rapidly. Atmospheric iron loadings and dust flux variations on the Loess Plateau are consistent with the dust fluxes of ODP 885/886 wells and the oceanic deposition rate of bioalloyed ODP 882 wells, both showing an increasing trend from 6.0 Ma to 2.7 Ma . This shows that the exchange of dust and sea air is most likely to affect ocean productivity through the mechanism of iron fertilizer. From 3.6 Ma to 2.7 Ma, there is a high degree of consistency between the iron load and the paleocean productivity and global atmospheric CO 2 changes in the North Pacific, indicating that the increase of dust / iron flux and its various feedback effects are likely to accelerate the Great Ice Age of the Northern Hemisphere .