76255 (75) Banded Impact Melt Breccia
We would like to thank the following for the use of this sample:
76255 is a banded impact melt breccia with a large clast of crushed norite and several small white clasts. The matrix of 76255 is both fine-grained and clast-laiden. The texture of the matrix is sub-ophitic with pyroxene and olivine oikocrysts, small spherical vesicles, and abundant mineral and lithic clasts. However, the matrix is variable with finer-grained, dark material intermixed with coarser-grained light material. The plagioclase inclusions in the breccia matrix are very calcic. Rotation 1 shows a clast-laiden area containing a pyroxene crystal with exceptional exsolution features. Rotation 2 focuses on an olivine-rich region within a large anorthositic clast.
The sample weighed 406.6 grams before analysis and has been dated at 4.02±0.04 billion years (Ar/Ar).
Further details of this and other Apollo samples are here: http://curator.jsc.nasa.gov/lunar/
Our thin section has been coated for analysis and some of this coat remins in fractures within the sample (visible in reflected light)
Ma = Millions of years ago
Rock forming mineral: