60618 (3) Anorthosite in Impact Melt
We would like to thank the following for the use of this sample:
60618 is a rake sample collected close to the Lunar Module. It contains large plagioclase crystals in a grey matrix with prominent vesicles. On first impression it appears to be a porphyritic basalt but it is actually composed of two lithologies anorthosite and impact-melt rock. The impact-melt rock portion contains many relatively large equant (0.5 mm) plagioclase grains (which are relicts) and plagioclase needles (up to 0.5 mm) which crystallized from the melt. Irregular olivine and pyroxene subophitically enclose the plagioclase. Minor phases include ilmenite, armalcolite, metallic iron, schreibersite and troilite (difficult to see in our thin section).
Our thin section image shows a sequence of numbers (1-6) that have been scribed on the glass behind the six rock fragments.
The sample weighed 21.7 grams before analysis and has not been dated.
Further details of this and other Apollo samples are here: http://curator.jsc.nasa.gov/lunar/
Ma = Millions of years ago
Rock forming mineral:
- metallic iron,