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Basaltic impact melts in the apollo collections: how many impacts and which events are recorded?
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Spudis, Paul D. |
| Copyright Year | 1992 |
| Description | Many of the rocks in the Apollo collections from the lunar highlands are impact melt breccias of basaltic bulk composition. They are known by a variety of names including low-K Fra Mauro basalt, VHA basalt, and basaltic impact melts. These rocks have been studied to understand the compositional nature of the lunar crust, to decipher the processes of large body impact, and to comprehend the record of impact bombardment of the Moon. Study of terrestrial craters has led to a model for impact melt generation whereby target lithologies are totally melted during impact. The impact melt makes up a few percent of the total volume of crater material; superheated silicate liquids of the impact melt have extremely low viscosities and mix intimately. This mixing thoroughly homogenizes the melt chemically during the excavation of the crater. Colder, unmelted debris is overridden by the melt sheet as the crater cavity grows. Incorporation of these cold clasts rapidly chills the melt, with zones of greater and lesser amounts of clasts being primarily responsible for modestly differing thermal regimes. The net effect of this process is the production of a suite of rocks that have extreme chemical homogeneity, but wide petrographic diversity. Strict application of this model to the petrogenesis of basaltic impact melts from the Moon has some fairly significant consequences for how we interpret early lunar history. The consequences are briefly discussed. |
| File Size | 406427 |
| Page Count | 3 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19930009624 |
| Archival Resource Key | ark:/13960/t8cg4mw39 |
| Language | English |
| Publisher Date | 1992-12-02 |
| Access Restriction | Open |
| Subject Keyword | Lunar And Planetary Exploration Geochronology Petrography Lunar Geology Lunar Crust Lunar Landing Sites Silicates Apollo 17 Flight Breccia Lunar Rocks Impact Melts Petrology Highlands Lithology Lunar Craters Homogeneity Basalt Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Technical Report |
