Cretaceous basaltic terranes in Western Colombia: Elemental, chronological and Sr-Nd isotopic constraints on petrogenesis

• Main Authors: A. C. Kerr, G. F. Marriner, J. Tarney, A. Nivia, A. D. Saunders, M. F. Thirlwall, C. W. Sinton
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1997
• Subjects: Pacific; Iceland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.513.3384; http://petrology.oxfordjournals.org/content/38/6/677.full.pdf

Accreted terranes comprising Mid to Late Cretaceous picrites, basalts an oceanic spreading centre, and valuable comparisons can be made between Iceland and the Caribbean–Colombian plateau.and dolerites occur in three north–south trending belts in western Colombia, in the Central Cordillera, Western Cordillera and along the Pacific coast. The geochemistry of these rocks is consistent with an oceanic plateau (plume-related) origin, and they most probably formed in the Pacific as part of the Caribbean oceanic plateau. KEY WORDS: basalt; Colombia; geochemistry; mantle plume; oceanicThese igneous rocks display small but significant inter-cordillera plateauvariations, being younger and more depleted in incompatible trace element ratios (and with more positive eNd values) to the west. The igneous rocks of the Pacific coast (Serranı́a de Baudó) are dated at 73–78 Ma ( 40Ar/39Ar), and those of the Western Cordillera at INTRODUCTION~90 Ma, whereas the volcanics of the Central Cordillera are The relative contribution of lithospheric vs as-believed to be older than 100 Ma. Most of the igneous rocks are thenospheric (plume) mantle sources to continental floodbasaltic, and it is suggested that they have fractionated from picritic basalt volcanism is a contentious subject in the pet-primary magmas, generated by partial melting within a hot mantle