LPI Seminar Series

Effective January 1, 2011, LPI seminars will be held on Fridays.

LPI seminars are held from 3:30–4:30 p.m. in the Lecture Hall at USRA, 3600 Bay Area Boulevard, Houston, Texas. Refreshments are served at 4:30 p.m. For more information, please contact Georgiana Kramer (phone: 281-486-2141; e-mail:kramer@lpi.usra.edu) or Oliver White (phone: 281-486-2148; e-mail: white@lpi.usra.edu). A map of the Clear Lake area (PDF format) is available here. The Acrobat Reader 8.0 is available from Adobe. This schedule is subject to revision.

See also the Rice University Department of Physics and Astronomy Colloquia and the Department of Earth Science Colloquia pages for other space science talks in the Houston area.

June 2012

Friday, June 1, 2012 - Lecture Hall, 3:30 PM

Arlin Crotts, Columbia University
Lunar Volatiles: Sources and Resources

It is now clear that hydration on the Moon of both internal and external originhas been discovered. One can easily hypothesize a diversity of sources: comets/asteroids, the solar wind, the lunar interior, and even the interstellar medium. How can we further characterize and discriminate between volatiles from these sources? Can we characterize how have they changed over time? We describe several approaches to accomplishing this.

Friday, June 8, 2012 - Lecture Hall, 3:30 PM

Dave Blewett, Johns Hopkins University, APL
Mercury Hollows

High-resolution images of Mercury's surface returned by MESSENGER reveal a class of unusual depressions, mostly associated with impact craters. Named hollows, these depressions are shallow with rounded outlines and flat floors. Many hollows have high-reflectance halos and interiors. The hollows have no analog on the Moon but do resemble the "Swiss cheese" terrain found in the polar regions of Mars, thought to form by sublimation of carbon dioxide ice. The morphology of the hollows suggests that they form through loss of a volatile phase when rocks are exposed to the harsh thermal and space-weathering environment of the mercurian surface. Compositional information collected by MESSENGER's elemental sensors over large areas of the planet indicates a higher-than-expected content of sulfur, thus sulfur-bearing minerals may be involved in the formation of the hollows. I will present an overview of these fascinating features and discuss how they fit with other evidence for relatively high volatile content in Mercury.

Friday, June 22, 2012 - Lecture Hall, 3:30 PM

William Farrand, Space Science Institute
Acid Sulfate Minerals in Mawrth Vallis and Related Areas on Mars

The Mawrth Vallis region has been recognized as having the most expansive exposures of Noachian-aged phyllosilicate bearing layered rocks on the surface of Mars. The Mawrth Vallis stratigraphy consists of a lower Mg/Fe smectite bearing unit and an upper unit containing an assortment of Al phyllosilicate minerals. Recently scattered occurrences of acid sulfate minerals such as jarosite and possibly alunite have been recognized in the region. These identifications have been made on the basis of reflectance spectra measured by the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on-board the Mars Reconnaissance Orbiter (MRO). The detection of occurrences of these minerals and their relevance for the early history of aqueous activity on Mars will be discussed.