Northwest South American Climate: A story recorded in late Pleistocene deep-sea sediments of the Carnegie Ridge

Donnerstag, 14. November 2013 - 14:00 Uhr
GEO-Gebäude, Raum 1550 (Hörsaal)
Daniel Rincón-Martínez

Over the past half-million years, precipitation along the coast of Ecuador has varied across glacial–interglacial cycles, with more aridity associated with glacial conditions, according to marine sediment-based reconstructions.

Daniel Rincón-Martínez of the Alfred-Wegener Institute for Polar and Marine Research, Germany, and colleagues used a suite of proxies to reconstruct ocean surface conditions in the equatorial eastern Pacific Ocean. They find the lowest amounts of terrestrial run-off during glacial periods, along with strong latitudinal and meridional sea-surface temperature gradients in the Pacific. The team attributes this to more La Niña-like conditions, coupled with a northward shift of the intertropical zone during glacial periods.

Globally, however, the intertropical zone is thought to shift southward during glacials. The contrasting movement in the equatorial eastern Pacific may be driven by strong glacial cooling in the southeast Pacific, which would locally push the intertropical convergence zone northward.