Lunar and Planetary Science XXXIII (2002) sess39.pdf

Wednesday, March 13, 2002 LUNAR : THE WIND CRIES MARE 8:30 a.m. Salon A

Chairs: J. J. Gillis K. Righter

Elphic R. C.* Lawrence D. J. Maurice S. Feldman W. C. Prettyman T. H. Gasnault O. M. Binder A. B. Lucey P. G. An Index for Evolved Lithologies on the Lunar Surface: Lunar Thorium-to-REE Ratio [#2009] Using neutron and gamma ray spectrometer data, we develop an “evolved lithology index” based on the ratio of thorium to rare earth element abundance. This is useful in identifying exotic compositions.

Gasnault O.* Lawrence D. J. Vaniman D. T. Elphic R. C. Feldman W. C. Systematics on Thorium in Lunar Basalts [#2010] We study the thorium content in basalts. A severe selection is made to make sure that the studied sub-dataset is representative of basaltic flows. The thorium distribution in those basalts presents strong patterns. Relation with iron, age, and topography are investigated.

Vaniman D.* Lawrence D. Gasnault O. Reedy R. Extending the Th-FeO Sampling Range at : Under the Footprint of Lunar Prospector [#1404] Using measured FeO and using K as a Th surrogate, glasses in Apollo 14 regolith breccias provide a wider sampling than other Apollo 14 samples. The range of variation compares broadly with that found by Lunar Prospector for the whole .

Gillis J. J.* Jolliff B. L. Korotev R. L. Lawrence D. J. The Origin of Elevated Th in the Eratosthenian Lava Flows in the Procellarum KREEP Terrane [#1934] spectral reflectance and compositional data, Lunar Prospector gamma ray and neutron spectrometer data, and sample analysis of lunar soils are used to examine the origin of high-Th in Eratosthenian basalts of the Procellarum KREEP Terrane

Lawrence D. J.* Elphic R. C. Feldman W. C. Gasnault O. Genetay I. Maurice S. Prettyman T. H. Small-Area Thorium Enhancements on the Lunar Surface [#1970] The spatial resolution of the LP-GRS global thorium abundances has been optimized and new abundances have been mapped onto 0.5° pixels. With this map, we identified a number of small-area (<60 km) thorium enhancements including the Compton/Belkovich thorium anomaly and Timocharis crater.

Staid M. I.* Pieters C. M. Gaddis L. R. Eliason E. Spectral Comparisons of Mare Basalts from Clementine UVVIS and NIR Data [#1795] Clementine UVVIS and NIR multispectral data are used to characterize the reflectance properties (0.4-2.0 microns) of the least weathered (most crystalline) and uncontaminated surfaces within major mare deposits.

Antonenko I.* Yingst R. A. Mare and Cryptomare Deposits in the Schickard Region of the Moon: New Measurements Using Clementine FeO Data [#1438] Clemetine FeO data was used to estimate thickness, area, and volume of mare and cryptomare units in the Schickard region of the Moon. The results show more mare patches than previously mapped in the area. Cryptomare units were also better defined.

Hawke B. R.* Lawrence D. J. Blewett D. T. Lucey P. G. Smith G. A. Taylor G. J. Spudis P. D. Remote Sensing Studies of Geochemical and Spectral Anomalies on the Nearside of the Moon [#1598] A variety of remote sensing data was used to determine the composition and origin of selected spectral anomalies (Red Spots) on the Moon.

Lunar and Planetary Science XXXIII (2002) sess39.pdf

Hiesinger H.* Head J. W. III Wolf U. Jaumann R. Neukum G. Thicknesses of Lunar Mare Flow Units: A New Investigation Based on Crater Size-Frequency Distribution Measurements [#1065] We used crater size-frequency distribution measurements in order to estimate the thickness and the volume of flow units in several nearside basins. We found that thicknesses of flow units are on the order of 30–60 m and volumes are about 590–940 km3.

Theno T. W.* Yingst R. A. Lava Pond Characterization in Mercurius Crater, Mercurius C, and the Surrounding Region [#1926] We surveyed the lava ponds within the Mercurius region for inclusion in ongoing lava pond mapping and classification. Pond morphology, FeO and TiO2 content, depth, and volume, were used to provide a more detailed geologic picture of the region.

Shih C.-Y.* Nyquist L. E. Reese Y. Wiesmann H. Nazarov M. A. Taylor L. A. The Chronology and Petrogenesis of the Mare Clast from Lunar Meteorite Dhofar 287: Rb-Sr and Sm- Nd Isotopic Studies [#1344] The Sm-Nd isochron for lunar mare basalt meteorite Dhofar 287A yields T=3.46±0.03 Ga and ε_Nd = –0.6 ± 0.3. Its Rb-Sr isotopic system is severely altered. The basalt is unique, probably coming from an enriched mantle source.

Righter K.* Nickel and Cobalt Partitioning Between Spinel and Basaltic Melt: Applications to Planetary Basalt Suites [#1253] New experimental spinel/melt partition coefficients for Ni and Co have been measured in basalt samples with natural levels of Ni and Co, are lower than previous high doping experiments, and are applied to several planetary basalt suites.

Yakovlev O. I. Dikov Yu. P. Gerasimov M. V.* Wlotzka F. Huth J. The Behavior of Pt in Silicate Melts During Impact-simulated High Temperature Heating [#1271] Experimental simulation of an impact vaporization of a Pt-rich target shows the formation of Pt-Fe particles. The formation of metallic iron phases during an impact provides appropriate conditions for the separation of Pt into a metallic iron phase.