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Pervasive mantle plume head heterogeneity: Evidence from the late Cretaceous Caribbean-Colombian oceanic plateau

Kerr, Andrew Craig, Tarney, John, Kempton, Pamela D., Spadea, Piera, Nivia, Alvaro, Marriner, Giselle F. and Duncan, Robert A. 2002. Pervasive mantle plume head heterogeneity: Evidence from the late Cretaceous Caribbean-Colombian oceanic plateau. Journal of Geophysical Research: Solid Earth 107 (B7) , 2140. 10.1029/2001JB000790|

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Abstract

In SW Colombia picritic pillow lavas and tuffs, as well as breccias composed of picritic clasts, occur interspersed with basalts of the Central Cordillera and represent accreted portions of the ∼90 Ma Colombian/Caribbean oceanic plateau (CCOP). We present new geochemical data for these picrites and high-MgO basalts from SW Colombia, along with new data from Deep Sea Drilling Project Leg 15 drill sites. The 40Ar/39Ar ages for the CCOP in the Central Colombian Cordillera range from 87 to 93 Ma. Both SW Colombia picrites and Leg 15 basalts are compositionally diverse and range from reasonably enriched ((La/Nd)n > 1 and (εNd)i < +4.1) to relatively depleted ((La/Nd)n < 1 and (εNd)i > +8.0). Nb/Y and Zr/Y systematics suggest that the depleted component is not depleted MORB mantle, but is an intrinsic part of the plume. The bulk of the CCOP compositions can be explained by mixing between this depleted mantle and a HIMU component. However, radiogenic isotope systematics indicate the presence of an EM2 (or possibly EM1) component within the plume. Mantle melt modeling suggests that the enriched magma types are the product of deeper, small degree melting of a pervasively heterogeneous plume comprising a refractory matrix with enriched streaks/blobs, whereas shallower, more extensive melting, results in the formation of relatively depleted magmas.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Earth and Ocean Sciences
Uncontrolled Keywords: mantle plume ; Mantle melting ; Oceanic plateau ; Picrite ; Komatiite ; Colombia
Additional Information: Pdf uploaded in accordance with publisher's policy at http://www.sherpa.ac.uk/romeo/issn/2169-9356/ (accessed 20/02/2014).
Publisher: American Geophysical Union
ISSN: 2169-9356
Date of First Compliant Deposit: 30 March 2016
Date of Acceptance: 13 January 2002
Last Modified: 14 Feb 2019 12:36
URI: http://orca.cf.ac.uk/id/eprint/1296

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