72315 (78) Impact Melt Breccia
Click the microscope button to view a thin section for this sample.
Click the microscope button to view a thin section for this sample.

Fact sheet

72315 (78) Impact Melt Breccia

72315 was thought to be an anorthositic clast (light-coloured patch) in the host rock. However, the sample turned out to be mostly an impact melt breccia – same as the other samples collected from this location (see 72395). It contains abundant mineral clasts, but only minor recognizable clasts of granulitic anorthosite or norite. It is a vesicular impact melt with a characteristic micro-poikilitic texture. It is about 80 % matrix with about 15 % mineral clasts and ~5 % annealed lithic clasts. It also has about 3 % pore space as small irregular vugs. The crystalline matrix of 72315 is composed of interlocking grains of plagioclase, pyroxene and olivine with small, poorly-developed poikilitic pyroxene and ilmenite enclosing laths of plagioclase and rounded inclusions of olivine. Plagioclase in 72315 often has undulatory extinction, and is sometimes feathery (maskelynite devitrification). Apatite, armalcolite and metallic iron with a meteoritic origin are the accessory species. An assortment of mineral clasts are shown in rotations 1 and 2.

The sample weighed 131.4 grams before analysis and has not been dated.

A transcript of the dialogue between astronauts Eugene A. (Gene) Cernan (CDR) and Harrison P. (Jack) Schmitt (LMP) as they sampled this boulder is available on the Lunar and Planetary Institute site.

Further details of this and other Apollo samples are here: http://curator.jsc.nasa.gov/lunar/

About this collection

Apollo 17, the final manned landing mission, had two objectives: to obtain samples of ancient rocks from the lunar highlands and to look for evidence of younger volcanic activity on the valley floor.

This small Collection contains material deriving from both periods, including igneous rocks around 4.3 billion years old from the lunar highlands as well as younger volcanic samples dating from about 3.6 billion years ago.

Apollo 17 was launched on 7 December 1972.

Sample details

Collection: Apollo 17
Rock-forming mineral
Accessory minerals
metallic iron
Category guide  
Category Guide
Refers to any word or phrase that appears in the individual rock names. Names are generally descriptive; they allow users to search for broad terms like ‘granite’ as well as more specific names such as ‘breccia’. However, the adjacent descriptions of the specimens captures a wider range of general words and phrases and is a more powerful search tool.
Refers to any word or phrase that appears anywhere in the descriptions of the specimens
Accessory minerals
Minerals that occur in very low abundance in a rock. They are usually not visible with the naked eye and contribute perhapssver, they often dominate the rare elements such as platinum group metals.
Rock-forming minerals
Minerals that make up the bulk of all rock samples and are also the ones used in rock classi?cation.
Selecting one or more period, for example 'Jurassic'.
A term used to group together related samples that are not already gathered into a single Collection. For instance, there is a ‘SW England granites’ theme that includes such rock types as granite, hydrothermal breccia, skarn and vein samples.
A general term used to label a rock sample. It is a useful way of grouping similar samples throughout a collection. Category names are often, but not exclusively, common rock names (e.g. granite, basalt, dolerite, gabbro, greisen, skarn, gneiss, amphibolite, limestone, sandstone).
The owner of the sample that appears in the collection. For example, NASA owns all the samples that appear in the Moon Rocks collection
We would like to thank the following for the use of this sample: