Provenance of Cenozoic Siliciclastic Units in the Southern Gulf of Mexico by Heavy-Mineral Determinations and Geochemistry, and Detrital Zircon U-Pb Geochronology

Abstract

Abstract We established provenance of Cenozoic sequences sampled in wells in the southern and southwestern Gulf of Mexico by heavy mineral analysis and LAICPMS detrital zircon U-Pb ages. The age spectra are dominated by Cenozoic ages. Other populations are of Cretaceous, Late Permian-Early Triassic, and Neo-Mesoproterozoic ages. Minor Jurassic, Devonian, and Ordovician ages are included. Paleoproterozoic-Archean ages are related to the Amazonian craton. Meso-Neoproterozoic ages (1 Ga) are ubiquitous in Mexico (Oaxaquia terrane) and are related to the Grenville orogen. Neoproterozoic ages (750-550 Ma) were possibly derived from sedimentary rocks on the Panafrican orogen. Cambrian-Ordovician ages (490-450 Ma) might relate to plutons of the Esperanza suite of the Acatlán complex. Carboniferous and Permian ages (350-290 Ma) were possibly derived from the western Gondwanan arc. Permian and Triassic ages (290-250 Ma) may represent the east Mexican arc. Late Triassic and Jurassic ages (210-170 Ma) suggest a derivation from the Nazas arc in north-central Mexico. Late Jurassic ages (160 Ma) may represent the Jurassic magmatism associated with an extensional regime. Cretaceous ages (145 Ma) might be derived from Early Cretaceous arc of Mexico. Cretaceous ages (135-90 Ma) were possibly derived from the Alisitos-Peninsular Ranges arc. Late Cretaceous-Early Palaeogene ages (90-55 Ma) suggest relations with Laramide magmatism and the Late Cretaceous volcanic province in southern Mexico. Paleogene-Neogene zircons (50 Ma and younger) are likely related to Cenozoic volcanic arcs in Mexico such as the Sierra Madre Occidental. Three earlier recognised ignimbrite flare-ups in the Eocene-Oligocene, early Oligocene, and early Miocene, match our detrital zircon populations. Furthermore, Miocene units contain kyanite-sillimanite possibly related to medium- to highgrade rocks such as the Acatlán complex or the Guatemalan Chuacús complex. We discuss the provenance based on geochemistry of the heavy minerals.