AuthorsR. Nerlich, S. Clark and H. Bunge
TitleAn outlet for Pacific mantle: The Caribbean Sea?
Afilliation, Scientific Computing
StatusPublished
Publication TypeJournal Article
Year of Publication2015
JournalGeoResJ
Volume7
Pagination59-65
Date Published09/2015
PublisherElsevier
Abstract

The Pacific Ocean is surrounded by subduction zone systems leading to a decreasing
surface area as well as sub-surface mantle domain. In contrast, the Atlantic realm is
characterized by passive margins and growing in size. To maintain global mass balance,
the Caribbean and the Scotia Sea have been proposed as Pacific-to-Atlantic transfer
channels for sub-lithospheric shallow mantle. We concentrate on the Caribbean here and
test this idea by calculating the present-day regional dynamic topography in search for a
gradual decrease from west to east that mirrors the pressure gradient due to the shrinkage
of the Pacific. To calculate the dynamic topography, we isostatically correct the observed
topography for sediments and crustal thickness variations, and compare the result with
those predicted by lithospheric cooling models. The required age-grid was derived from
our recently published reconstruction model. Our results confirm previous geochemical
and shear-wave splitting studies and suggest some lateral asthenosphere flow away from
the Galapagos hotspot. However, they also indicate that this flow is blocked in the Central
Caribbean. This observation suggests that rather than through large scale Pacific-to-
Atlantic shallow mantle flow, the global mass balance is maintained through some other
process, possibly related to the deep mantle underneath Africa.

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