Li Mingsong, a researcher at the School of Earth and Space, has made progress in the study of the Paleocene-Eocene extreme heat event

5600 years ago, due to huge carbon emissions, a warming event occurred on the earth, and the global average temperature rose rapidly by about 5 ° C, marking a fundamental shift
in the earth's climate system from a warmroom state to a hot chamber state.

Paleocene-Eocene Extreme Heat Event Recovery Diagram (Kump, 2011)

To pinpoint the spatiotemporal evolution of this extreme heat event, a high-resolution chronological stratigraphic framework is essential
.

The results show that this extreme heat event reached its peak
in less than 6,000 years.

Deposition records
of Paleocene-Eocene extreme heat events.

Specifically, the fine chronological structure of this extreme heat event remains controversial
.

The sedimentary strata in the work area selected for this study to record PETM events are thicker, up to 5-15 meters, and the sedimentation rate is more than ten times that of deep-sea sedimentation; The team conducted high-resolution elemental and petrophysical property scans of the obtained more than 100 meters of core over a period of 2 months, and obtained a number of high-quality paleoclimate replacement indicators, such as calcium content and susceptibility
.

Drilling location map (shown by red five-pointed star)

Using these data, based on the astronomical theory of climate change proposed by Milankovich, the research team used a variety of objective sedimentary rate visualization methods to identify the astronomical orbital period in the sedimentary record, completed the conversion from stratigraphic depth to geological time, and obtained a highly reliable astronomical dating scale
.

The astronomical chronology of the Paleocene-Eocene extreme heat event, with the red area representing the span of the event's initiation period

This age can help us decipher the triggering mechanism
of this extreme heat event.

Previous proposed triggers include volcanic activity related to the North Atlantic volcanic rock province, carbon release from natural gas hydrates, carbon burials and emissions controlled by orbital changes, asteroid impacts, etc
.

The study also provides ideas
for some of the scientific problems in this extreme heat event.

First, high-temperature environments are thought to be more prone to heavy rainfall and strong ablation, a process that together with intense silicate chemical weathering and rapid burial of organic carbon drives recovery
from PETM events.

Secondly, the Earth system transient simulation experiment reproduces the astronomical periodic signal of calcium content data in sediments, and the simulation results can be compared with the actual sedimentary records, which provides ideas
for the astronomical driving research of deep-time climate change.

Third, due to the dissolution of carbon dioxide, there has been a significant oceanic acidification event
around the world.

Earth system simulations and data comparisons suggest that astronomical drivers played a role in triggering the Paleocene-Eocene extreme heat event

The paper was recently published in the internationally renowned journal Nature Communications, and the first and corresponding author is Li Mingsong
.

The project has been funded
by the National Key R&D Program (2021YFA0718200), the Helsimmons Foundation (2016-11), the National Natural Science Foundation of China (42072040), and the Basic Research Business Expenses of Peking University Central Universities (7100603368).

Paper Information:

Li, M.