Enhanced terrestrial weathering/runoff and surface ocean carbonate production during the recovery stages of the Paleocene-Eocene thermal maximum
Enhanced terrestrial weathering/runoff and surface ocean carbonate production during the recovery stages of the Paleocene-Eocene thermal maximum
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DOI：
10.1029/2005pa001163
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发表时间：
2005-12-17
期刊：
影响因子：
--
通讯作者：
Schellenberg, SA
中科院分区：
文献类型：
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作者：
Kelly, DC;Zachos, JC;Schellenberg, SA
[1]在被称为古新世-始新世热极大期（PETM）（约55 Ma）的短暂全球变暖事件期间，海洋的碳酸盐饱和度剖面明显变浅。据信，大量碳迅速释放到海洋-大气系统中引发了这一强烈的溶解事件，沿着伴随着碳同位素的负偏移。PETM的短暂（120 - 220 kyr）反映了地球外生碳循环中负反馈机制的快速增强，起到了缓冲海洋pH值和降低大气温室气体水平的双重作用。对大洋钻探计划690号站点（威德尔海）的PETM地层学的详细研究表明，CIE恢复期比CIE开始时间晚约80 kyr，由一个扩展的（约2.5 m厚）间隔代表，该间隔包含一个独特的被颗石藻碳酸盐强烈稀释的南极有孔虫组合。总的来说，微体古生物学和沉积学的变化保存在CIE恢复间隔反映了一个短暂的状态时，海洋大气化学促进多产的颗石藻水华，抑制当地溶跃层相对较深的深度。粘土矿物高岭石丰度的一个显著峰值与CIE恢复间隔有关，表明大陆风化/径流也在此时加强（Robert和肯内特，1994年）。这种平行的地层变化通常与增强的大陆风化/径流和碳酸盐沉淀有助于在PETM恢复期（例如，例如，在一个实施例中，狄更斯等人，1997; Zachos等人，2005年）。
[1] The carbonate saturation profile of the oceans shoaled markedly during a transient global warming event known as the Paleocene-Eocene thermal maximum (PETM) ( circa 55 Ma). The rapid release of large quantities of carbon into the ocean-atmosphere system is believed to have triggered this intense episode of dissolution along with a negative carbon isotope excursion (CIE). The brevity ( 120 - 220 kyr) of the PETM reflects the rapid enhancement of negative feedback mechanisms within Earth's exogenic carbon cycle that served the dual function of buffering ocean pH and reducing atmospheric greenhouse gas levels. Detailed study of the PETM stratigraphy from Ocean Drilling Program Site 690 (Weddell Sea) reveals that the CIE recovery period, which postdates the CIE onset by similar to 80 kyr, is represented by an expanded ( similar to 2.5 m thick) interval containing a unique planktic foraminiferal assemblage strongly diluted by coccolithophore carbonate. Collectively, the micropaleontological and sedimentological changes preserved within the CIE recovery interval reflect a transient state when ocean-atmosphere chemistry fostered prolific coccolithophore blooms that suppressed the local lysocline to relatively deeper depths. A prominent peak in the abundance of the clay mineral kaolinite is associated with the CIE recovery interval, indicating that continental weathering/runoff intensified at this time as well ( Robert and Kennett, 1994). Such parallel stratigraphic changes are generally consonant with the hypothesis that enhanced continental weathering/ runoff and carbonate precipitation helped sequester carbon during the PETM recovery period ( e. g., Dickens et al., 1997; Zachos et al., 2005).