61015 (44) Dimict Breccia
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Fact sheet

61015 (44) Dimict Breccia

61015 is one of the best examples of the Apollo 16 dimict breccias. These breccias consist of anorthositic material and impact melt rock with high aluminium content. It consists of roughly about 75% impact melt and 25% anorthosite lithologies. The impact melt (rotation 2) seems to have intruded the anorthosite lithology (rotation 1) and has recrystallized. The plagioclase in the anorthositic material is extremely fractured and deformed by impact processes. Plagioclase has patchy and undulatory extinction, contains healed shears, and locally contains patches of narrow shock-induced twin lamellae. Pyroxenes within the anorthosite show undulatory extinction and very locally augite contains shock-induced twinning. Most of the melt-rock has a fine-grained intersertal texture and largely consists of a mat of randomly oriented plagioclase laths, equant grains of olivine, sub-ophitically enclosing the plagioclase, and microcrystalline dark brown mesostasis filling the interstices. Included within this mat are rare large olivine grains, small pink spinels and globules of intergrown iron-schreibersite-troilite.

The sample weighed 1789 grams before analysis and has been dated at 3.90 ± 0.036 billion years (Ar/Ar).

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

About this collection

The Apollo 16 landing site was in the hilly region around Descartes crater in the lunar highlands. The landing spot was chosen to allow the astronauts to gather geologically older lunar material (Descartes Formation and the Cayley Formation) than the samples obtained in the first four landings, which were in or near lunar maria.

The mission lasted 11.1 days, with a stay on the lunar surface of 71 hours. The crew were on the lunar surface for 20.2 hours during which they traversed approximately 27 kilometers and collected approximately 96 kilograms of samples.

Apollo 16 was launched on 16 April 1972.

Sample details

Collection: Apollo 16
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: