Distal "impact" layers and global acidification of ocean water at the Cretaceous-Paleogene boundary (KPB)

作者：Premovic P I^*

来源：Geochemistry International, 2011, 49(1): 55-65.

DOI：10.1134/S0016702911010095

• Cretaceous-Paleogene
• &quot
• impact&quot
• layer
• global acidification
• ocean water

The KPB sections at Hojerup in Denmark, Agost and Caravaca in Spain and El Kef in Tunisia and (elsewhere in the world) consists of a very thin reddish biogenic calcite-poor smectite-rich "impact" layer overlain by a thicker smectite-rich marl. The massive amount of impact-generated atmospheric CO2 at KPB would have accumulated globally in the ocean surface, leading to acidification and CaCO3 undersaturation. These chemical changes would have induced a low biocalcification of calcareous plankton and a high dissolution of their shells. The biocalcification/dissolution crises may have played a significant role for the low abundance of biogenic calcite in the "impact" layer of the marine boundary clays at Hojerup, Agost, Caravaca and El Kef (and elsewhere in the world). Experimental data and observations indicate that the deposition of the "impact" layer probably lasted only a few decades at most.

• 出版日期2011-1