77017 (194) Feldspathic Granulitic Impactite
We would like to thank the following for the use of this sample:
77017 contains a large, annealed feldpathic breccia set in a frothy black glass matrix. The feldspathic portion is an annealed gabbroic rock that has been recognized as an impactite, because it contains a high concentration of meteoritic siderophile elements. Shock features indicate subsequent impact followed by the addition of black glass of mare composition. The feldspathic portion has been described as an olivine-bearing, anorthositic gabbro with a relatively coarse-grained poikilitic (or poikiloblastic) texture (rotation 1). There are also areas with relict lithic clasts of annealed troctolitic anorthosite and anorthosite. Mineral clasts of plagioclase, olivine, pink spinel and ilmenite are enclosed within pigeonite and augite oikocrysts.
Dating of the sample indicates that a major metamorphic event forming the feldspathic portion was at about 4 b.y., whereas the glass-forming event was about ~1.5 b.y.
The sample weighed 1730 grams before analysis.
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