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Accession Number N20130009074
Title Testing the Origins of Basalt Fragments from Apollo 16.
Publication Date 2013
Media Count 2p
Personal Author C. R. Neal P. H. Donohue R. A. Zeigler R. E. Stevens
Abstract Several 2-4 mm regolith fragments of basalt from the Apollo 16 site were recently described by (1). These included a high-Ti vitrophyric basalts (60603,10-16) and one very-low-titanium (VLT) crystalline basalt (65703,9-13). As Apollo 16 was the only highlands sample return mission distant from the maria, identification of basaltic samples at the site indicates input from remote sites via impact processes (1). However, distinguishing between impact melt and pristine basalt can be notoriously difficult and requires significant sample material (2-6). The crystal stratigraphy method utilizes essentially non-destructive methods to make these distinctions (7,8). Crystal stratigraphy combines quantitative petrography in the form of crystal size distributions (CSDs) coupled with mineral geochemistry to reveal the petrogenetic history of samples. The classic CSD plot of crystal size versus population density can reveal insights on growth/cooling rates, residence times, and magma history which in turn can be used to evaluate basaltic vs impact melt origin (7-9). Electron microprobe (EMP) and laser ablation (LA)-ICP-MS analyses of mineral phases complement textural investigations. Trace element variations document subtle changes occurring during the formation of the samples, and are key in the interpretation and preservation of this rare lunar sample collection.
Keywords Basalt
Geochemistry
Impact melts
Lunar rocks
Mineralogy
Petrography
Regolith
Sample return missions
Size distribution
Titanium
Trace elements

 
Source Agency National Aeronautics and Space Administration
NTIS Subject Category 54 - Astronomy & Astrophysics
84B - Extraterrestial Exploration
Corporate Author Goddard Space Flight Center, Greenbelt, MD.
Document Type Conference proceedings
Title Note N/A
NTIS Issue Number 1319
Contract Number N/A

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