TY  - JOUR
A1  - Weber, Marion
A1  - Cardona, A.
A1  - Valencia, V.
A1  - Altenberger, Uwe
A1  - Lopez-Martinez, M.
A1  - Tobon, M.
A1  - Zapata, Sebastian Henao
A1  - Zapata, G.
A1  - Concha, A. E.
T1  - Geochemistry and geochronology of the Guajira Eclogites, northern Colombia evidence of a metamorphosed primitive Cretaceous Caribbean Island-arc
JF  - Geologica acta
N2  - The chemical composition of eclogites, found as boulders in a Tertiary conglomerate from the Guajira Peninsula, Colombia suggests that these rocks are mainly metamorphosed basaltic andesites. They are depleted in LILE elements compared to MORB, have a negative Nb-anomaly and flat to enriched REE patterns, suggesting that their protoliths evolved in a subduction related tectonic setting. They show island-arc affinities and are similar to primitive island-arc rocks described in the Caribbean. The geochemical characteristics are comparable to low-grade greenschists from the nearby Etpana Terrane, which are interpreted as part of a Cretaceous intra-oceanic arc. These data support evidence that the eclogites and the Etpana terrane rocks formed from the same volcano-sedimentary sequence. Part of this sequence was accreted onto the margin and another was incorporated into the subduction channel and metamorphosed at eclogite facies conditions. Ar-40-Ar-39 ages of 79.2 +/- 1.1Ma and 82.2 +/- 2.5Ma determined on white micas, separated from two eclogite samples, are interpreted to be related to the cooling of the main metamorphic event. The formation of a common volcano-sedimentary protolith and subsequent metamorphism of these units record the ongoing Late Cretaceous continental subduction of the South American margin within the Caribbean intra-oceanic arc subduction zone. This gave way to an arc-continent collision between the Caribbean and the South American plates, where this sequence was exhumed after the Campanian.
KW  - Eclogites
KW  - Primitive island-arc
KW  - Geochronology
KW  - Guajira Peninsula
KW  - Colombia
KW  - Caribbean
Y1  - 2011
U6  - https://doi.org/10.1344/105.000001740
SN  - 1695-6133
VL  - 9
IS  - 3-4
SP  - 425
EP  - 443
PB  - Facultat de Geologia, Divisio III, Ciències Experimentals i Matemàtiques, Universitat de Barcelona
CY  - Barcelona
ER  -