EPS Research News | The Department of Earth & Planetary Sciences

August 2023

Abrupt Northwest Atlantic deep-sea oxygenation decline preceded the Palaeocene-Eocene Thermal Maximum

Ellen Thomas

Widespread oceanic deoxygenation occurred during the Paleocene/Eocene Thermal Maximum (PETM), but its exact timing and regional variability remains poorly understood. We use magnetofossils at two IODP sites in the NW Atlantic ocean (paleodepth ~ 2900, 4400 m) to trace regional palaeoredox changes. Deep-sea oxygenation started to decrease gradually several hundred thousand years before the PETM, and reached a minimum ∼50 ky before the PETM. We provide evidence for precursors to PETM warming, and suggest that ocean circulation changes might have played an important role in triggering carbon release to the ocean-atmosphere system at the PETM onset.

Xue, P., Chang, L., and Thomas, E., 2023. Abrupt Northwest Atlantic deep-sea oxygenation decline preceded the Palaeocene-Eocene Thermal Maximum. Earth & Planetary Sciences, 618, 118304, doi: 10.1016/j.epsl.2023.118304

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Pannotia: To be or not to be?

R. Damian Nance

The existence of a supercontinent (Pannotia) at the Precambrian-Cambrian boundary, an idea that was popular when the supercontinent cycle first gained popularity, has recently come into question with profound implications, not only for the duration of the cycle, but also for the geodynamic pathway followed by the cycle from the breakup of Rodinia to the assembly of Pangea. This article outlines the origin of Pannotia’s fall from grace and reviews the evidence for and against its existence, the ramifications of either outcome, and some avenues by which the issue might be resolved.

The supercontinent cycle and Earth’s long-term climate

R. Damian Nance

As an introduction to the ANYAS special issue “The Year in Climate Science Research” this article examines the role of the supercontinent cycle in governing long-term global climate. This rests largely on the cycle’s influence on global sea level, continental erosion and silicate weathering, and the consequent abundance of CO2 and other greenhouse gases in the atmosphere. Other roles reflect the cycle’s control of continental geography and the association of supercontinent amalgamation and breakup with the emplacement of large igneous provinces (LIPS).

September 2022

Slab-driven flow at the base of the mantle beneath the northeastern Pacific Ocean
Jonathan Wolf, Maureen Long

August 2022

Talk by Dr. Darius Modirrousta-Galian - Role of Planetary Winds in Planet Evolution and Population. IAU Symposia, South Korea, (Invited talk).

July 2022

Precipitation efficiency constraint on climate change
Nature Climate Change
Ryan Li
Falling raindrops have an essential but as yet unquantified role in planetary climate change. An approach to quantifying precipitation efficiency establishes that the way raindrops reach the surface plays an important part in persistent uncertainties over future tropical atmospheric circulation and extreme precipitation.