Ancient lithospheric source for Quaternary lavas in Hispaniola

作者：Kamenov George D^*; Perfit Michael R; Lewis John F; Goss Adam R; Arevalo Ricardo Jr; Shuster Robert D

来源：Nature Geoscience, 2011, 4(8): 554-557.

DOI：10.1038/NGEO1203

Fragments of ancient continental lithosphere, entrained in the shallow oceanic mantle, have been found in a number of locations in the Southern Hemisphere(1-4), including rare arc settings(5). Lavas erupted in these locations exhibit Pb isotopic characteristics that are similar to the so-called enriched mantle 1 reservoir(1), one of the end-members that define the isotopic composition of the Earth's mantle. However, no lavas with isotopic signatures resembling enriched mantle 1 have been identified in the Caribbean region. Here we present isotopic analyses for mafic-alkaline lavas from Quaternary volcanic centres in Hispaniola. We identify unusual isotopic characteristics indicating the presence of a mantle component similar to enriched mantle 1 beneath Hispaniola. Furthermore, we find evidence for an involvement of this mantle component in the genesis of spatially associated calk-alkaline lavas. On the basis of these isotopic systematics we estimate that the mafic-alkaline lavas are derived from an ancient lithospheric fragment with affinities to the supercontinent Gondwana. We conclude that the fragment originated from the Grenvillian terranes of Central America and Mexico, which also have affinities to Gondwana(6), indicating that Hispaniola interacted tectonically with these terranes.

• 出版日期2011-8