Deccan Traps, Asteroids and Planktonic Foraminifera
Abstract
The end of the Cretaceous recorded two dramatic external events, the eruptions related to the large igneous province (LIP) emplacement of the Deccan traps in India and an asteroid impact leading to the Cretaceous/Palaeogene (K/Pg) mass extinction, approximately 66 Ma. How this volcanic event and the associated CO2 degassing and warming affected the marine environment and ecosystem has been largely overshadowed by the more dramatic changes associated with the asteroid impact. The two events operated over very different timescales, with the Deccan traps extruding over approximately 100,000 years compared to the geologically instantaneous asteroid impact. Therefore, they provide a unique opportunity to contrast the response of marine ecosystems to relatively long- and short-term environmental perturbation.
The impact resulted in a loss of over 90% of marine calcifies (with a focus on planktonic foraminifera and coccolithophores in the pelagic realm) and a major decrease in planktonic foraminifera size across the world's oceans. To compare the two drivers of environmental change, we generated a record of biotic response across the two events. Here we present a high-resolution planktonic foraminifera size record through the Late Maastrichtian and K/Pg boundary event. We analyse core material from Ocean Drilling Program Site 1262 in the South Atlantic and Site 1049 in the North Atlantic to quantify the magnitude of biotic change for the two events. The Deccan trap eruption leads to a shallowing of the CCD and an increase in fragmentation while the KPg is associated with a deepening of the CCD and improved preservation. A decrease in size is evident in the late Maastrichtian approximately 300 kyrs before the K/Pg consistent with the Deccan Trap outgassing; it is overshadowed, however, by the larger and more permanent size decrease associated with the asteroid impact at the K/Pg boundary.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.V24A..05B
- Keywords:
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- 0473 Paleoclimatology and paleoceanography;
- BIOGEOSCIENCES;
- 4912 Biogeochemical cycles;
- processes;
- and modeling;
- PALEOCEANOGRAPHY;
- 8137 Hotspots;
- large igneous provinces;
- and flood basalt volcanism;
- TECTONOPHYSICS;
- 8408 Volcano/climate interactions;
- VOLCANOLOGY