72215 (181) Aphanitic Impact Melt Breccia
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Fact sheet

72215 (181) Aphanitic Impact Melt Breccia

72215 was collected from the side of a layered boulder. Samples 72235, 72255 and 72275 are from other layers in this boulder. It contains intricate swirls of light and dark, interlayered, crushed highland materials produced in an as yet unexplained fluidized impact mechanism. The dark portions are finer-grained and the lighter are coarser-grained, but both portions are found to have similar bulk composition. Six domains have been described.

The sample is a coherent, clast-rich, impact melt breccia. It is aluminous and feldspathic and contains numerous small patches of granitic material. The granitic clasts have high silica (>75%) and high K2O contents (~6%). They are made of various intergrowths of silica, Ba-K feldspar, plagioclase feldspar and Fe-rich pyroxene. Some basalt clasts contain pink spinel. Rotations shows clasts of anorthositic norite.

The sample weighed 379.2 grams before analysis and has been dated at 3.83-4.02 billion years (Ar/Ar).

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: