Strong Coupling Between Carbon Cycle, Climate, and Weathering During the Paleocene-Eocene Thermal Maximum

The Paleocene-Eocene Thermal Maximum (PETM; similar to 56 Ma)-a geologically rapid carbon-release event similar to anthropogenic carbon emissions-is ideal for investigating weathering responses to rapid carbon release and associated climate change. Here, for the first time, we present high-resolution lacustrine lithium isotope data that reflect basin-scale silicate weathering across the PETM in the Nanyang Basin, eastern China. Our results reveal an similar to 100% increase in regional silicate weathering intensity through the PETM relative to the pre-PETM level. Synchronous variations between carbon isotope values and weathering intensity demonstrate a strong coupling between carbon cycle, climate, and chemical weathering on millennial timescales. These findings argue that strong negative weathering feedback and massive removal of CO2 maintained Earth's climate within a habitable range during the PETM. Plain Language Summary The chemical breakdown of silicate minerals on continents is a major regulator of climate via atmospheric CO2 removal on million-year timescales; however, on shorter timescales of greater relevance to understanding the fate of anthropogenic CO2, the link between silicate weathering and climate remains unclear. The Paleocene-Eocene Thermal Maximum (PETM; similar to 56 Ma)-a geologically rapid carbon-release event similar to anthropogenic carbon emissions-represents an ideal interval for investigating weathering responses to rapid carbon release and climate change. Here, we measured the chemistry of lacustrine sediments that span the PETM in the Nanyang Basin, eastern China to reveal the link between silicate weathering and rapid carbon release. We find that regional silicate weathering increased by similar to 100% through the PETM. Our results also demonstrate that carbon release, climate change, and silicate chemical weathering were closely coupled over millennial time scales. Strong negative silicate weathering feedback and massive removal of (CO2) maintained Earth's climate within a habitable range across the PETM.