An early Eocene transient warming ( ˜ 53 Ma): Implications for astronomically-paced early Eocene hyperthermal events.

Details An early Eocene transient warming ( ˜ 53 Ma): Implications for astronomically-paced early Eocene hyperthermal events. An early Eocene transient warming ( ˜ 53 Ma): Implications for astronomically-paced early Eocene hyperthermal events.

Dec 2004

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agufmpp14a..03s&link_type=abstract

American Geophysical Union, Fall Meeting 2004, abstract #PP14A-03

Other

1610 Atmosphere (0315, 0325), 1615 Biogeochemical Processes (4805), 1620 Climate Dynamics (3309)

Scientific paper

Here we report on a pronounced hyperthermal event approximately 2 Myrs after the Paleocene-Eocene thermal maximum (PETM) and place both events in a new orbitally-tuned framework. This previously unrecognized transient event and the underlying PETM were both recovered at five sites along a 2km depth transect on the Walvis Ridge (southeast Atlantic) during Ocean Drilling Program Leg 208. Similar to the PETM, this event, \textit{Elmo}, is marked by a red clay layer, associated with severe drop in CaCO3 concentrations, suggesting a ˜ 2 km rise in the lysocline. High-resolution (1cm) bulk carbonate δ 13C measurements of the shallowest, and hence most complete Site 1263 revealed a ˜ 1.5% drop in δ 13C and δ 18O. The negative δ 13C excursion is composed of three steep steps of which the last one corresponds to the base of the red clay layer. The post-\textit{Elmo} interval mirrors the typical PETM signature with an exponential recovery to pre-excursion δ 13C values. The planktonic foraminiferal δ 13C record (measured on single specimens of the surface dweller \textit{Acaranina soldadoensis}) confirms the bulk pattern, although the amplitude of the excursion, ˜ -2.5, is larger. The planktonic foraminiferal δ 18O record shows the same ˜ -1% excursion as the bulk, suggesting a fast increase in sea surface temperature of ˜ 4 degrees C. The case of conditions similar to the PETM during the ELMO event is further strengthened by the occurrence of low diversity, diminutive benthic foraminifer assemblages, and a decrease in planktonic foraminifer diversity. Examination of published isotope, X-ray fluorescence and magnetic susceptibility records further indicates that this event is global in nature and recorded in other marine and terrestrial basins. Orbital tuning of the deepest Sites 1262 magnetic susceptibility and Sites 1262 and 1267 color reflectance records to the La2004 and R7 astronomical solutions shows that the \textit{Elmo} is five 400-kyr eccentricity cycles younger than the PETM and that both events are linked to eccentricity-maxima. This, and the subtle resemblance between the \textit{Elmo} and PETM mentioned above, suggests that similar, astronomically modulated, mechanisms are at the root of them. The leading hypothesis to explain the PETM climatic event and its δ 13C excursion is the dissociation of submarine methane hydrates. If the \textit{Elmo} shares a similar origin, its less extreme appearance may be associated with the ability of the methane hydrate reservoir to recharge after the PETM, especially under the warm conditions that prevailed in the interval spanning the two events.

Affiliated with

Also associated with

No associations

Rating

An early Eocene transient warming ( ˜ 53 Ma): Implications for astronomically-paced early Eocene hyperthermal events. does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with An early Eocene transient warming ( ˜ 53 Ma): Implications for astronomically-paced early Eocene hyperthermal events., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and An early Eocene transient warming ( ˜ 53 Ma): Implications for astronomically-paced early Eocene hyperthermal events. will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1456165