--> ABSTRACT: Evaluation of the Close-Out of Deep-Marine Deposition in the Magallanes/Austral Basin, Patagonian Chile and Argentina, by Schwartz, Theresa; Malkowski, Matthew ; Graham, Stephan; #90142 (2012)

Datapages, Inc.Print this page

Evaluation of the Close-Out of Deep-Marine Deposition in the Magallanes/Austral Basin, Patagonian Chile and Argentina

Schwartz, Theresa *1; Malkowski, Matthew 1; Graham, Stephan 1
(1) Geological & Environmental Sciences, Stanford University, Stanford, CA.

The Magallanes/Austral Basin of Patagonian Chile and Argentina contains a thick succession of Jurassic to Miocene rocks that record the evolution of the Andean orogen and eastward-adjacent foreland basin system. The Upper Cretaceous fill of the Magallanes Basin records periodic deposition into the early, Deepwater phase of the retroforeland basin, with each depositional pulse related to thrust-front propagation and resulting in a unique depositional style. The Latest Cretaceous to Paleocene Dorotea Formation reflects the final phase of marine deposition, recording southward shelf-edge delta progradation and progressive shallowing in the basin. A regional Paleocene unconformity separates the Dorotea Formation from the overlying, dominantly terrestrial Eocene Río Turbio Formation. This drastic change in facies is accompanied by a distinct change in provenance, illustrated by a pronounced increase in volcanic detritus, as well as a large-scale change in paleodispersal, from foredeep-axial (north to south) to transverse across the incipient wedge top (west to east). Coupled with other recent detrital zircon provenance work, this indicates regional uplift immediately east of the orogen, structural inversion of the Late Cretaceous foredeep, and recycling of its sedimentary fill into a new, eastward-displaced basin tract.

 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California