U/Pb detrital zircon provenance from late cretaceous metamorphic units of the Guajira Peninsula, Colombia: Tectonic implications on the collision between the Caribbean arc and the South American margin
Academic Article
Mesozoic metamorphic units exposed along the northern margin of the South American plate record the different stages of subduction evolution or arc-continent collision between the margins of the Caribbean plate and the South American continent. U-Pb detrital zircon geochronology for provenance analysis was carried out on meta-sedimentary rocks of the Etpana formation and metamorphic boulders found within a nearby Tertiary conglomerate, including high-pressure rocks in the Colombian Caribbean. All samples have similar age populations, suggesting that they share a relatively common source and paleogeography. Prominent age peaks include Meso and Paleoproterozoic ages of ca. 1624. Ma and 1315. Ma, Cambrian to Neoproterozoic ages of ca. 630. Ma, 580. Ma and 547. Ma, and less abundant Jurassic and Permian ages of ca. 270. Ma and 160. Ma, which indicate that the South American margin is a major source for the sedimentary protoliths. There are also remnants of younger Cretaceous allocthonous Caribbean arc input at ca. 90-70. Ma. The deposition and metamorphism of these units records 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, and sediments with continental signatures were incorporated into the subduction channel and the accretionary wedge. As convergence continued, sediments derived from a mix of South American and arc sources were deposited and included in the collisional wedge up until ylt;71. Ma.
