EPSS Colloquium - spring-2014

April 3, 2014
4 p.m. - 5 p.m.
Geology 3656

Presented By:

• Jonathan Mitchell - UCLA

Seminar Description coming soon.

April 10, 2014
4 p.m. - 5 p.m.
Geology 3656

Presented By:

• Ulrike Seibt - UCLA

Seminar Description coming soon.

April 17, 2014
4 p.m. - 5 p.m.
Geology 3656

Presented By:

• Edwin Schauble - UCLA

Though rare, heavy elements such as mercury, lead and uranium are of great interest as economic resources, pollutants, and potential tracers of critical environmental variables such as oxygen abundance. Variation in their isotope abundances gives a more detailed and robust picture of their behavior than elemental abundances alone. For instance, signatures in the three radiogenic isotopes of lead provided key insights for understanding environmental lead pollution. Alas, few elements show such rich variation in their isotopic compositions. Only recently have developments in mass spectrometry led to the discovery that (much more subtle) non-radiogenic variations are common in heavy elements, including mercury, thallium and uranium. This talk will focus on attempts to understand what causes isotopic variability in heavy metals, and what insights might be gained from high-precision isotope abundance measurements.

April 24, 2014
4 p.m. - 5 p.m.
Geology 3656

Presented By:

• Caroline Beghein - UCLA

Seminar Description coming soon.

May 1, 2014
4 p.m. - 5 p.m.
Geology 3656

Presented By:

• Aradhna Tripati - UCLA

Seminar Description coming soon.

May 8, 2014
4 p.m. - 5 p.m.
Geology 3656

Presented By:

• Jon Aurnou -

Seminar Description coming soon.

May 15, 2014
4 p.m. - 3 p.m.
Geology 3656

Presented By:

• Jean-Luc Margot - UCLA

The Arecibo and Goldstone planetary radars are the most powerful tools for Earth-based characterization of the physical properties and dynamics of many Near-Earth Asteroids (NEAs). This characterization is essential in multiple contexts: scientific understanding of the asteroid population, impact hazard mitigation, human exploration, and resource utilization. I will review the unique role that UCLA plays in this field. Our work includes the detailed physical characterization of NEAs, orbit computations for binaries and triples, astrometric measurements, Yarkovsky drift determinations, training of radar observers, development of key hardware and software, improvements to asteroid shape modeling techniques, and development of a publicly available database for archival of asteroid radar results (http://radarastronomy.org).

May 22, 2014
4 p.m. - 5 p.m.
Geology 3656

Presented By:

• Laurence Smith - UCLA

The runoff of water melted from the Greenland Ice Sheet (GrIS) surface is thought to generate one-half to two-thirds of its total mass loss to the global ocean, yet its surface remains one of the least studied hydrological systems on Earth. This talk combines rare in situ channel hydraulic measurements with high-resolution remote sensing of the ice sheet surface to show that well-organized supraglacial river networks flowing over and into the ice sheet are the dominant mechanism by which meltwater is removed from the GrIS ablation surface for delivery to the global ocean. Comparison of observed proglacial (terrestrial) and supraglacial river discharge with modeled surface mass balance from a regional climate model sheds useful insights on a standard current practice for computing GrIS runoff contributions to global sea level rise.

May 29, 2014
4 p.m. - 5 p.m.
Geology 3656

Presented By:

• Lingsen Meng - UCLA

Seminar Description coming soon.

June 5, 2014
4 p.m. - 5 p.m.
Geology 3656

Presented By:

• Axel Schmitt - UCLA

Seminar Description coming soon.