Dr. Mark Jellinek - The climate footprint of Earth's super continental cycles

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Dr. Mark Jellinek, UBC

Vendredi 15 novembre 2019 à 11h00 - Friday, November 15, 2019 at 11:00 am

Gill Room, FDA 232, 3450 rue Université, Université McGill

Résumé / Abstract:

Supercontinent assembly and breakup can influence the rate and global extent to which insulated and relatively warm subcontinental mantle is mixed globally, potentially introducing lateral oceanic-continental mantle temperature variations that regulate volcanic and weathering controls on Earth's long-term carbon cycle for a few hundred million years. Whereas the relatively warm and unchanging climate of the Nuna supercontinental epoch (1.8-1.3 Ga) is potentially characteristic of thorough mantle thermal mixing, the extreme cooling-warming climate variability of the Neoproterozoic Rodinia episode (1-0.63 Ga), as well as the more modest but similar climate change of the Mesozoic Pangea cycle (0.3-0.05 Ga) are potentially effects of subcontinental mantle thermal isolation with differing longevity. A tectonically-modulated carbon cycle model coupled to a one-dimensional energy balance climate model predicts a warm and ice-free climate during the Nuna epoch as well as the qualitative form of Mesozoic climate evolution expressed in tropical sea-surface temperature and ice sheet proxy data. Applied to the Neoproterozoic, depending on the predominate modes of chemical weathering, this supercontinental control on can drive Earth into, as well as out of, a continuous or intermittently pan-glacial climate, consistent with aspects of proxy data for the Cryogenian-Ediacaran period. The timing and magnitude of this cooling-warming climate variability depends, however, on the detailed character of mantle thermal mixing, which is incompletely constrained. Furthermore, LIP as well as explosive volcanism as well as a predicted tectonically-paced abiotic methane production at mid-ocean ridges can modulate the intensity of this climate change.

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The climate footprint of Earth's super continental cycles

Ajouter au calendrier 2019-11-15 11:00:00 2019-11-06 21:43:20 Dr. Mark Jellinek - The climate footprint of Earth's super continental cycles Résumé / Abstract: Supercontinent assembly and breakup can influence the rate and global extent to which insulated and relatively warm subcontinental mantle is mixed globally, potentially introducing lateral oceanic-continental mantle temperature variations that regulate volcanic and weathering controls on Earth's long-term carbon cycle for a few hundred million years. Whereas the relatively warm and unchanging climate of the Nuna supercontinental epoch (1.8-1.3 Ga) is potentially characteristic of thorough mantle thermal mixing, the extreme cooling-warming climate variability of the Neoproterozoic Rodinia episode (1-0.63 Ga), as well as the more modest but similar climate change of the Mesozoic Pangea cycle (0.3-0.05 Ga) are potentially effects of subcontinental mantle thermal isolation with differing longevity. A tectonically-modulated carbon cycle model coupled to a one-dimensional energy balance climate model predicts a warm and ice-free climate during the Nuna epoch as well as the qualitative form of Mesozoic climate evolution expressed in tropical sea-surface temperature and ice sheet proxy data. Applied to the Neoproterozoic, depending on the predominate modes of chemical weathering, this supercontinental control on can drive Earth into, as well as out of, a continuous or intermittently pan-glacial climate, consistent with aspects of proxy data for the Cryogenian-Ediacaran period. The timing and magnitude of this cooling-warming climate variability depends, however, on the detailed character of mantle thermal mixing, which is incompletely constrained. Furthermore, LIP as well as explosive volcanism as well as a predicted tectonically-paced abiotic methane production at mid-ocean ridges can modulate the intensity of this climate change. Gill Room, FDA 232, 3450 rue Université, Université McGill Geotop admin@example.com America/New_York public