Carbonate deposition in the Arctic during the Paleocene Eocene Thermal Maximum (PETM) and Early Eocene Climatic Optimum (EECO)

Abstract

Recently-acquired, high-quality seismic reflection profiles document the presence of possible carbonate deposits on the Mendeleev Rise in the Arctic Ocean during the Paleocene-Eocene Thermal Maximum and the Early Eocene Climatic Optimum. These deposits are concentrated at the crests of bathymetric highs and consist of clusters of buildups comprising small patch reefs overlain by larger, coalesced platforms, followed by back-stepped higher-relief platforms. The small buildups commonly are ∼ 100–500 m in diameter and 50–100 m in height. The larger platforms are up to 3–7 km wide and up to 400 m thick. Some of the larger buildups are characterized by internal horizontally layered architecture, whereas others are characterized internally by clinoforms suggesting progradational growth. A common characteristic of these buildups is that they tend to achieve a common height (i.e., their tops align along the same level), typical of buildups sensitive to growth within the photic zone, whose upward growth is limited by sea level. The succession of buildup styles indicates carbonate factories under the influence of accelerating relative sea-level rise, which culminated in drowning and ultimate abandonment.