The application of detrital zircon U-Pb and Lu-Hf isotope systematics to sediment provenance, basin configuration and paleogeographic issues of Neoproterozoic to Lower Paleozoic strata in northwestern South America.
Thick sedimentary successions of lower Paleozoic and potentially late Neoproterozoic strata are buried under the Andean foreland deposits of the Colombian Llanos Basin. However, despite the geodynamic importance of these units as tracers for a crucial time interval during the tectonic development of northern South America, our knowledge about their stratigraphy, sediment provenance and general basin configuration is still very limited.
The Neoproterozoic Era was a period of fast plate reaccommodations, during which the break-up of the supercontinent Rodinia led to the development of a passive-margin along northern Gondwana and eventually to the diachronous initiation of Avalonian-type magmatic arc activity. Timing constraints for most of these events have been inferred from geochronologic, stratigraphic, and isotopic studies performed on a variety of the so-called peri-Gondwanan terranes of the Appalachian and Variscan orogens, but very few modern studies have taken place in northern South America that would allow these timing and terrane-sourcing hypotheses to be tested. This project seeks to partially fill this gap by performing U-Pb geochronological and Lu-Hf isotopic analysis on detrital zircons extracted from this Cryogenian to Ordovician (?) Amazonian miogeocline, on samples collected from outcrops of the Araracuara Fm. in eastern Colombia and recovered from deep exploratory wells drilled in the Llanos basin. Our results will provide first-order insights into the timing of Neoproterozoic-Paleozoic basin formation, as well as provide other critical paleogeographic information that will prove crucial to better understand the economic potential of these successions and for evaluating peri-Gondwanide terrane linkages.