University of Connecticut

Events Calendar

Geography colloquium - Julie Fosdick

Friday, November 6, 2015
12:20pm – 1:15pm

Storrs Campus
AUST 434

Rising mountains and retreating seas: Unraveling tectonic and climatic controls on Cenozoic paleogeography in the Patagonian Andes

Tectonics, climate, and changes in global sea level influence (1) fluctuations between marine and terrestrial conditions along continental margins, (2) growth of mountainous topography, (3) rates of erosion and sediment delivery to the oceans, and (4) biogeography and major biotic events. Complex tectonic plate boundaries with narrow (<250 km) terrestrial connections between landmasses are especially sensitive to these processes, such as the early Cenozoic archipelago and coastal plain connecting Tierra del Fuego and the northern Antarctic Peninsula prior to opening of Drake Passage. With the emergence of a new paradigm in the last two decades recognizing the dynamic interactions among these processes, it has become all the more essential to differentiate between their signals (timing, tempo, magnitude) in the stratigraphic record.

This study centers on improving our understanding of the timing and controls of basin subsidence, marine transgressions, and continental sediment dispersal patterns in the Magallanes-Austral region of South America during middle Cenozoic time. In Patagonia and Tierra del Fuego, several middle Cenozoic transgressions have been linked to global sea level rise due to climate, but it is as of yet undetermined to what extent these phases were driven by tectonic subsidence and changes in upland sediment supply or eustasy alone. New stratigraphy, sedimentary provenance analysis, and thermochronology data track changes in paleogeography of upland orogenic source areas during deposition, signaling a tectonic control on sedimentation patterns. Additionally, youngest detrital age components of zircon U/Pb geochronologic data from middle Cenozoic strata suggest significantly younger depositional ages than previously thought for the these deposits, motivating the need for rethinking of their depositional connections to changes in Cenozoic climate and/or phases of deformation in the active Andean orogenic belt.


Lisa Park Boush []

Geography Department (primary), Geosciences, UConn Master Calendar

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