Implications of reduced turbidity current and landslide activity for the Initial Eocene Thermal Maximum – evidence from two distal, deep-water sites

Michael A Clare,Peter J Talling,James E Hunt

doi:10.1016/j.epsl.2015.03.022

Michael A Clare, Peter J Talling + Show 1 more

Open Access

https://doi.org/10.1016/j.epsl.2015.03.022

Copy DOI

Abstract

Previous studies propose that submarine landslides and turbidity currents may become more likely due to future rapid global warming. Determining whether global warming increases likelihood assists in assessment of landslide-triggered tsunami hazards and risk to seafloor structures. Other studies propose that landslides helped to trigger past rapid climate change due to sudden release of gas hydrates. Two deep-water turbidite records show prolonged hiatuses in turbidity current activity during the Initial Eocene Thermal Maximum (IETM) at ∼55 Ma. The IETM represents a possible proxy for future anthropogenically-induced climate change. It is likely that our records mainly represent large and fast moving disintegrative submarine landslides. Statistical analysis of long term (>2.3 Myr) records shows that turbidity current frequency significantly decreased after the IETM. Our results indicate that rapid climate change does not necessarily cause increased turbidity current activity, and do not provide evidence for landslides as a primary trigger for the IETM.

Highlights

A period of unusually rapid global warming occurred at ∼55 Ma (McInerney and Wing, 2011), termed the Initial Eocene Thermal Maximum (IETM)
We suggest that effects of rapid climatic change during the IETM at Zumaia may have reduced the likelihood of turbidity current activity – both immediately before and during the IETM
Several previous predictions suggested landslide and turbidity current activity should increase during periods of rapid global warming, due to dissociation of marine hydrates

Summary

Introduction

A period of unusually rapid global warming occurred at ∼55 Ma (McInerney and Wing, 2011), termed the Initial Eocene Thermal Maximum (IETM). This hyperthermal represents the warmest period on Earth during the Cenozoic (Schmitz et al, 2001), featuring, at its peak, a dramatic 6–8 ◦C warming of global deep waters over a period of approximately 10 kyr (Kennett and Stott, 1991). Other causal mechanisms have been invoked (Dunkley-Jones et al, 2010), but emissions of methane from marine hydrates are one of the most widely held explanations for IETM (Dickens et al, 1995; Katz et al, 1999, 2001). It has been proposed that rapid global warming will lead to significant increases in landslide and turbidity current fre-

Methods

Results

Discussion

Conclusion