Terrestrial record of methane hydrate dissociation in the Early Cretaceous
Abstract
Reconstruction of changing C isotopic composition of Early Cretaceous atmospheric CO2 from fossilized C3 vascular land-plant tissue revealed a brief and striking negative excursion (Δ ≈ -5‰) in atmospheric δ13C, followed by a rapid positive compensation (Δ ≈ +5‰) during the Aptian (ca. 117 Ma). Mass-balance calculations show that dissociation of a small amount of methane gas hydrate is the most tenable cause of the negative excursion; this would also result in an increased CO2:O2 mixing ratio as O2 is consumed during CH4 oxidation to CO2, spurring the exponential phase of angiosperm biogeographic expansion.
- Publication:
-
Geology
- Pub Date:
- February 2001
- DOI:
- 10.1130/0091-7613(2001)029<0159:TROMHD>2.0.CO;2
- Bibcode:
- 2001Geo....29..159J