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

Abstract

[1] 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 40 Ar/ 39 Ar 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 (e Nd ) i < +4.1) to relatively depleted ((La/Nd) n < 1 and (e Nd ) 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.

Asthenosphere–lithosphere interaction triggered by a slab window during ridge subduction: Trace element and Sr–Nd–Hf–Os isotopic evidence from Late Carboniferous tholeiites in the western Junggar area (NW China)

“…6a, plumerelated lavas plot between two parallel lines, and oceanic plateau basalts also plot between these lines (Kerr et al, 1997), whereas N-MORB and arc lavas plot at lower values (Fitton et al, 1997). All the Hatu basalts plot within the plume-derived field along with Caribbean and Ontong Java plateaux data, which are mafic igneous provinces generally attributed to ascending mantle plumes (Kerr et al, 2002). Although the Hatu basalts are geochemically similar to these oceanic plateau basalts and plot in the plume-derived field in the Nb/Y-Zr/Y plot, there is a lack of supporting evidence for their origin in oceanic plateau.…”

“…It is important to note that the trace element distributions and isotope geochemical compositions of the Hatu basalts share many features in common with those found in modern and Phanerozoic oceanic plateaux (e.g., the Caribbean and Ontong Java plateaux; Kerr et al, 2002;Hastie and Kerr, 2010;Hastie et al, 2008;). The log-log Nb/Y-Zr/Y plot has proved to be a robust discriminant between basalts derived from DMM source regions and from mantle plumes (oceanic island and plateau basalts) and the Zr/Y and Nb/Y ratios display only small variations with low-pressure crystal fractionation and partial melting processes (Fitton et al, 1997).…”

The basaltic volcanism of the Dumisseau Formation in the Sierra de Bahoruco, SW Dominican Republic: a record of the mantle plume magmatism of the Caribbean Large Igneous Province

“…La parte sumergida del plateau en el Mar Caribe fue muestreada durante las perforaciones de los proyectos DSDP Leg 15 y ODP Leg 163 (Donnelly et al, 1990). No obstante, secuencias emergidas del CLIP afloran en Jamaica, La Española, Puerto Rico, bordes costeros de Venezuela, Curaçao y las islas de Aruba, la costa Pacífica de América Central, y el occidente de Colombia y Ecuador (Lapierre et al, 2000;Kerr et al, 2002;Hastie et al, 2008). El CLIP incluye rocas volcá-nicas emitidas en tres grandes fases de diferente edad: 124-112 Ma (Lapierre et al, 2000;EscuderViruete et al, 2007), 94-83 Ma (la aparentemente más voluminosa; Kerr et al, 1997;Sinton et al, 1998;Hastie et al, 2008) y 80-72 Ma (Révillon et al, 2000;Escuder-Viruete et al, 2011).…”

High resolution magnetic, regional gravity and petrophysical characterization of the Dominican Republic tectonic domains with special focus on the Central Cordillera

“…This terrane is composed of Upper Cretaceous basalts similar to those that form the substratum of the Caribbean Sea (Maurrasse et al, 1979;Sen et al, 1988;Mann, 1999;Kerr et al, 2002).…”