Paleocene/Eocene carbon feedbacks triggered by volcanic activity

Abstract

The Paleocene–Eocene Thermal Maximum (PETM) was a period of geologically-rapid carbon release and global warming ~56 million years ago. Although modelling, outcrop and proxy records suggest volcanic carbon release occurred, it has not yet been possible to identify the PETM trigger, or if multiple reservoirs of carbon were involved. Here we report elevated levels of mercury relative to organic carbon—a proxy for volcanism—directly preceding and within the early PETM from two North Sea sedimentary cores, signifying pulsed volcanism from the North Atlantic Igneous Province likely provided the trigger and subsequently sustained elevated CO2. However, the PETM onset coincides with a mercury low, suggesting at least one other carbon reservoir released significant greenhouse gases in response to initial warming. Our results support the existence of ‘tipping points’ in the Earth system, which can trigger release of additional carbon reservoirs and drive Earth’s climate into a hotter state.

Unraveling ecological signals from a global warming event of the past

“… 5 ). Recent work suggests the triggering carbon source was volcanic in origin ( 6 – 8 ) and released in less than 5,000 y ( 9 ). The volume and geologically rapid nature of this carbon release is what makes the PETM a useful analog for modern-day CO 2 emissions, although it should be noted that the rate of carbon release is over significantly different timescales: hundreds of years in the present day, in comparison to thousands of years during the PETM ( 7 ).…”

Reduced plate motion controlled timing of Early Jurassic Karoo-Ferrar large igneous province volcanism

“…The plate reconstruction model used here suggests that also the emergence of the Iceland hot spot from under Greenland’s east coast, after the craton had migrated westward, instigated (together with nearby mid-ocean spreading ridges) basalt emplacement, leading to the onset and first phase of North Atlantic Igneous Province volcanism at ~60 Ma (Fig. 5B) ( 65 , 85 ), followed by a second phase of magmatism at ~56 Ma, possibly causing the Paleocene-Eocene Thermal Maximum ( 28 , 86 ). These observations may suggest that the migration and velocity of the Greenland craton initially effectively suppressed the surface expression of the Iceland Plume, with a hot spot track only forming when the thick cratonic lithosphere migrated away to make room for thinner proto-oceanic crust.…”

Cenozoic igneous activity in Northern China as a mechanism for late Oligocene climate warming

“…Plausible mechanisms include mountain building, recon gurations in oceanic gateways, and orbital forcing [3][4][5][6][7] . A very important mechanism driving climate warming, extrusive and intrusive igneous activity, is also suggested as a main cause of past global warming, such as during the early Jurassic warming and the well-known PETM 8,9,13,15,[45][46][47] . However, this mechanism is seldom being documented in literature to be one of the mechanisms for the LOW event, despite that more than six episodes of major climatic and environmental perturbations throughout geological history were correlated with the formation of Large Igneous Provinces (LIPs) such as the Permo-Triassic Extinction Event (~ 251 Ma), the Toarcian Oceanic Anoxic Event (~ 183 Ma), and in the early Eocene climatic optimum (~ 55 Ma) 9,13,[48][49][50][51] .…”