Peraluminous igneous rocks as an indicator of thermogenic methane release from the North Atlantic Volcanic Province at the time of the Paleocene–Eocene Thermal Maximum (PETM)
- 716 Downloads
Unusual cordierite-bearing peraluminous dacites, produced by melting of organic-rich sediments by intrusion of basaltic magma, are found within the North Atlantic Volcanic Province (NAVP). Calculations suggest that formation of the dacites, radiometric dated at 55.9 ± 0.3 Ma and possibly widespread, could have released an average of ∼4,500 Gt (range from 3,000 to 6,000 Gt) of carbon as methane, with a δ13C of about −35‰. Published model results suggest that such a methane release could explain the negative δ13C excursion in the oceans and atmosphere, the extreme global warming, and the marked dissolution of carbonates in the deep oceans that accompanied the concurrent Paleocene–Eocene Thermal Maximum (PETM). Outgassing from melting of sediments and formation of dacites, possibly in conjunction with methane produced in contact metamorphic aureoles and by methane hydrate release, provides a novel way of explaining the PETM and its timing.
KeywordsNorth Atlantic Volcanic Province Paleocene–Eocene Thermal Maximum Peraluminous dacites
Thanks to S. Self, Th. Thordarson, H. Svensen, A. Miles, and S. Galeotti for careful reading of the paper.
- Boulter MC, Manum SB (1989) The Brito-Arctic igneous province flora around the Paleocene/Eocene boundary. In: Eldholm O, et al. (eds) Proceedings of the Ocean Drilling Program, Scientific Results 104, 663–680Google Scholar
- Colosimo A, Bralower TJ, Zachos JC (2006) Evidence for lysocline shoaling at the Paleocene–Eocene Thermal Maximum on Shatsky Rise, Northwest Pacific In: Bralower T, et al. (eds), Proceedings of the ocean drilling program Scientific Results 198, 1–36Google Scholar
- Isaksen GH, Wilkinson DR, Hitchen K (2000) Geochemistry of organic-rich Cretaceous and Jurassic mudstones in the West Lewis and West Flannan basins, offshore north-west Scotland: implications for source rock presence in the north-east Rockall Trough. Marine Petrol Geol 17:27–42CrossRefGoogle Scholar
- Joppen M, White RS (1990) The structure and subsidence of Rockall Trough from two-ship seismic experiments. Jour Geophys Res 95(19):821, 837Google Scholar
- LeHuray AP, Johnson ES (1989) Rb-Sr systematics of Site 642 volcanic rocks and alteration minerals. In: Eldholm O, et al. (eds) Proceedings of the Ocean Drilling Program, Scientific Results 104: 437–448Google Scholar
- Lipinski M, Warning B, Brumsack H-J (2003) Trace metal signatures of Jurassic/Cretaceous black shales from the Norwegian Shelf and the Barents Sea. Palaeogeogr Palaeoclimatol Palaeoecol 190:459–475Google Scholar
- Murphy B, Lyle M, Olivarez-Lyle A (2006) Biogenic burial across the Paleocene–Eocene boundary: Ocean Drilling Program Site 1221 In: Wilson PA, et al. (eds) Proceedings of the Ocean Drilling Program, Scientific Results. 199:Google Scholar
- Parson LM, Viereck LG, Love D, Gibson I, Morton AC, Hertogen J (1989) The petrology of the Lower Series volcanics, ODP site 642. In: Eldholm O, Thiede J, Taylor E, et al. (1989) Proceedings of the Ocean Drilling Program, Scientific Results 104B: 993–1030Google Scholar
- Saunders AD, Fitton JG, Kerr AC, Norry MJ, Kent RW (1997) The North Atlantic Igneous Province. In: Mahoney JJ, Coffin MF (eds) Large Igneous Provinces, Geophys Monogr 100: 45–93. Amer Geophys Union, Washington DCGoogle Scholar
- Sinton CW, Hitchen K Duncan, RA (1998) Ar-40-Ar-39 geochronology of silicic and basic volcanic rocks on the margins of the North Atlantic. Geol Mag 135:161–171Google Scholar