Bibcode
Lindstrom, D. J.; Wentworth, S. J.; Martinez, R. R.; McKay, D. S.
Referencia bibliográfica
In Lunar Science Inst., Workshop on Geology of the Apollo 17 Landing Site p 29-31 (SEE N93-18786 06-91)
Fecha de publicación:
12
1992
Número de citas
0
Número de citas referidas
0
Descripción
The Apollo 17 double drive tube 79001/2 (station 9, Van Serg Crater) is
distinctive because of its extreme maturity, abundance, and variety of
glass clasts. It contains mare glasses of both high Ti and very low Ti
(VLT) compositions, and highland glasses of all compositions common in
lunar regolith samples: highland basalt (feldspathic; Al2O3 greater than
23 wt percent), KREEP (Al2O3 less than 23 wt percent, K2O greater than
0.25 wt percent), and low-K Fra Mauro (LKFM; Al2O3 less than 23 wt
percent, K2O less than 0.25 wt percent). It also contains rare specimens
of high-alumina, silica-poor (HASP), and ultra Mg glasses. HASP glasses
contain insufficient SiO2 to permit the calculation of a standard norm,
and are thought to be the product of volatilization during impact
melting. They have been studied by electron microprobe major-element
analysis techniques but have not previously been analyzed for trace
elements. The samples analyzed for this study were polished grain mounts
of the 90-160 micron fraction of four sieved samples from the 79001/2
core (depth range 2.3-11.5 cm). A total of 80 glasses were analyzed by
SEM/EDS and electron microprobe, and a subset of 33 of the glasses,
representing a wide range of compositional types, was chosen for
high-sensitivity INAA. A microdrilling device removed disks (mostly
50-100 micron diameter, weighing approx. 0.1-0.5 micro-g) for INAA.
Preliminary data reported here are based only on short counts done
within two weeks of irradiation.