12034 (32) - Regolith breccia
We would like to thank the following for the use of this sample:
12034 is a regolith breccia, but it is largely made up of components foreign to the Apollo 12 regolith and is from some distant, non-mare, regolith. It contains abundant KREEP basalt clasts; both as glasses and annealed lithic fragments. 12034 has not been dated. Sample 12034 is a fragmental matrix breccia similar in appearance to the Apollo 11 fragmental matrix breccias, but with a much lower porosity. It consists of a variety of glass, mineral and lithic clasts contained in a matrix of brown glass fragments and comminuted debris.
The texture of the matrix is seriate with fragments ranging in size from the limit of resolution up to 2 mm. Brown glass fragments dominate the less than 0.05 mm size fraction. The glass clast population in 12034 is extremely diverse, ranging from colorless, pale green, yellow or orange homogeneous glass to completely devitrified glass with included mineral grains . Subrounded to rounded fragments of maskelynite and devitrified maskelynite occur commonly as inclusions in the large devitrified glass clasts. Devitrification features in glass clasts take the form of variolitic clusters of plagioclase needles and more commonly axiolitic intergrowths of tightly packed plagioclase and pyroxene crystals. The lithic clasts in 12034 include basalts, dark-matrix breccia, cataclastic anorthosite and anorthositic gabbro. Rare basalts have textures ranging from ophitic to vitrophryic. Grey mottled basalt clasts in 12034 are made up of about half plagioclase and half low-Ca pyroxene and have the bulk composition of KREEP. They are probably fragments of impact melt.
The sample weighed 155 grams before analysis.
Further details of this and other Apollo samples are here: http://curator.jsc.nasa.gov/lunar/
Ma = Millions of years ago
- metallic iron