Petrology of a sequence of pyroclastic rocks from the valley of Taurus-Littrow (Apollo 17 landing site)
- Los Alamos Scientific Lab., NM
Samples collected from the rim of Shorty Crater, located in the valley of Taurus-Littrow (Apollo 17 landing site), including the orange glass droplets that have been the subject of a great deal of research and some controversy as to their origin. We have studied 13 samples from core 74001/2, collected at Shorty Crater; these samples represent most of the major stratigraphic units described by Nagle (1978). Below 5.5 cm, the samples consist entirely of whole and broken orange glass droplets and their partly to completely crystalline-black equivalents. We believe these droplets are pyroclastic ejecta from a lunar volcano. The crystalline droplets contain olivine and ilmenite as major phases. Minor phases include pyroxene, Cr-spinel, and metallic Fe. Four different properties of these droplets suggest that a wide range of cooling rates is represented. These properties are the grain shape, degree of crystallization, olivine shape or texture, and olivine composition. Many droplets contain vesicles indicating that a gas phase was involved in the eruption. Above a depth of 5.5 cm the core sequence has undergone in situ reworking by micrometeorites and contains exotic fragments including basalt and agglutinates. We conclude that the sequence below 5.5 cm, to a depth of 70 cm, represents 3.5 b.y. old volcanic pyroclastic ejecta which was deposited in a relatively short time period, was buried, and was subsequently brought to the lunar surface by the Shorty Crater impact where it was subjected to minor in situ reworking.
- OSTI ID:
- 5242266
- Journal Information:
- Geochim. Cosmochim. Acta, Suppl.; (United States), Journal Name: Geochim. Cosmochim. Acta, Suppl.; (United States)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Model for eruption behavior of a volcanic vent in Eastern Mare Serenitatis
Tomographic location of potential melt-bearing phenocrysts in lunar glass spherules