News & Events

Noon seminar - Neogene tectonic events in the West Antarctic rift: Implications for landscape

Monday, April 08, 2019, 12:15PM - 1:15PM

Speaker

Wesley LeMasurier

Location:

SEEC room S228 (Sievers Room)

Full title

Neogene tectonic events in the West Antarctic rift system: Implications for landscape evolution and environment of ice sheet formation

Abstract

The West Antarctic rift differs from other volcanically active rift systems of similar scale in two unusual respects: (1) the rift floor lies 1000–2000 m lower in elevation than others, and (2) five interior ice-filled troughs extend between 1500 m and 2555 m below sea level. Two of the troughs are more than twice the depth of Lake Baikal, the world's deepest lake. The Marie Byrd Land dome, by contrast, compares closely with the intra-rift Kenyan and Ethiopian domes in the East African rift. Comparisons between these rift systems suggest (1) that the West Antarctic rift interior is comparatively cool and volcanically inactive, which seems anomalous considering the scale of exposed volcanic activity, (2) it is likely that there have been intervals of extension and basin deepening beneath the ice sheet during Neogene time, and (3) that dome uplift and basin subsidence have greatly changed the West Antarctic landscape over the past 25 m.y. The West Antarctic ice sheet (WAIS) is the only continental-scale ice sheet on Earth today, or in the recent past, that rests on a tectonically active landscape. One implication of this evolution is that the WAIS, which is believed to have formed ~34 Ma, developed initially on a landscape of very low relief.

Refreshments

Coffee and cookies will be served at 11:45 in the hallway outside S228.

Audience

Free and open to the public.