Lunar and Planetary Institute

LPI Seminar Series

LPI seminars will be held on Thursdays.

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 Nicholas Castle (phone: 281-486-2144; e-mail: or Julia Semprich (phone: 281-486-2180; e-mail: A map of the Clear Lake area is available here. This schedule is subject to revision.

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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.

January 2019

Wednesday, January 23, 2019 - Lecture Hall, 3:30 PM

CANCELED Seungyeol Lee, University of Wisconsin-Madison
LPI Seminar: Application of Combined Techniques for Studying Nano-Minerals in Geological System
Modern technology allows us to detect, characterize, and understand the nature of nano-minerals. However, it is still challenging to determine its structure at the nanoscale when structures include the short-range ordering, defects, and local domains. I used integrated techniques (X-ray/Neutron diffraction, Pair distribution function, TEM, Z-contrast imaging) for solving this problem and applied some nano-minerals in geological environments. This presentation will several research examples: new nano-mineral observation (luogufengite and valleyite), crystal structure of minerals (6-line ferrihydrite, vernadite and low-temperature tridymite/cristobalite), nano-structure enhancing magnetic coercivity (lodestone and hemo-ilmenite).
Thursday, January 24, 2019 - Lecture Hall, 3:30 PM

Steven J Desch, Arizona State University
LPI Seminar: Ureilite Diamonds from Mars’s Core: A Tale of Three Planets, None of Them Lost
Recent analyses of mineral inclusions inside ~100 μm diamonds from the Almahata Sitta ureilite meteorite show they formed at pressures > 21 GPa, demanding origin inside a planet. We argue the diamonds are exogenous to the ureilite parent body (UPB) and instead formed at Mars’s core-mantle boundary. After floating to the top of Mars’s magma ocean, they and other materials were ejected in the Borealis basin impact early in Mars’s evolution. One fragment struck the UPB, which until then resembled other meteorite parent bodies like Vesta. The impact catastrophically disrupted the UPB. Mixing of Martian surface materials with the UPB material gave ureilites many of their unusual characteristics. We identify the asteroid 15 Eunomia as potentially the largest remnant of the collision, and 438 Zeuxo as a possible source of Almahata Sitta. We identify a dynamical pathway for delivery of ureilites to Earth. Ureilites may contain the only known samples of a planetary core.


Previous Seminars

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