We are pleased to share our newest publication coming out of the Chile Slope Systems project. This paper is led by Univ. of Calgary Ph.D. student Ben Daniels and is now online in the journal GSA Bulletin.
This study reports >6,600 new U-Pb zircon ages from the Upper Cretaceous Tres Pasos Formation in southern Chile. We’ve been investigating the sedimentology and stratigraphic architecture of these exceptional outcrops of slope strata for many years, but haven’t had a robust understanding of the timing until now.
Ben (with the help of others in the group) collected numerous sandstone samples for detrital zircons as well as two volcanic ash deposits. Together, the new geochronologic data constrain the age of distinct “phases” within the Tres Pasos Formation across a ~100 km long by ~2 km thick outcrop belt. With this framework, we discuss rates of progradation/aggradation, comparison to other well-studied slope/margin systems, and potential external controls on the basin-scale architecture. Additionally, we also include a discussion on the use of detrital zircon to calculate maximum depositional ages (MDAs) that will be of interest to anyone using detrital zircon geochronology for sedimentary system analysis.
The figure below (Fig. 2 from the paper) is a regional stratigraphic cross section showing the large-scale architecture, paleocurrent data, and these new U-Pb ages all in one chronostratigraphic framework.
Huge congrats to Ben on spearheading this effort!