Start date:
November 2015
End date:
December 2015
Wright Valley, Taylor Valley, Lake Joyce, Lake Vanda, Miers Valley, Garwood Valley, Hobbs Valley, Blue Glacier
Principle Investigator:
Dr. John M. Cottle
University of California-Santa Barbara
Rocks highly enriched in potassium such as lamprophyres potentially provide direct insight into of foundering and the processes that occur during, and immediately after, termination of subduction. These enigmatic rocks are important because they represent near−primary mantle melt compositions and therefore their age, geochemistry and petrologic evolution reveal key information on both the composition of the upper mantle and its thermal state. Of equal importance, they reveal how these key parameters vary through both space and time. This project will study a suite of lamprophyres spanning c.1300km along−strike and emplaced during the latest stages of the Neoproterozoic − Ordovician Ross orogeny, Antarctica. High−precision geochronology coupled with whole rock and mineral−scale elemental, isotope geochemical and petrologic analysis will elucidate the mechanisms for, and temporal and spatial scales over which, deep crustal foundering/delamination occurred and the processes responsible for the significant isotopic heterogeneities observed in these rocks.