65785 (4) Troctolite Clast in Impact Melt
Collection:
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Click the microscope button to view a thin section for this sample.
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Fact sheet

65785 (4) Troctolite Clast in Impact Melt

65785 is a crystalline feldspathic impact melt rock containing a coarse-grained pink spinel troctolite clast. Our thin section shows the troctolite only.  Modally the last contains 65% plagioclase (An98), 30% olivine (Fo85) and 5% Mg-Al spinel. The pink spinel occurs as one large crystal (1 mm). Irregular plagioclase grains (0.1–1 mm) are surrounded by one large olivine grain. Minor phases are pyroxene, ilmenite, armalcolite, rutile, metallic iron, troilite, whitlockite, farringtonite and K-feldspar.

The sample weighed 5.16 grams before analysis. The impact melt has been dated at 3.83 ± 0.02 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
Type
igneous
Rock-forming mineral
plagioclase
feldspar
olivine
Accessory minerals
pyroxene
ilmenite
armalcolite
rutile
metallic iron
troilite
whitlockite
farringtonite
k-feldspar
Category guide  
Category Guide
Title
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.
Description
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.
Timescale
Selecting one or more period, for example 'Jurassic'.
Theme
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.
Category
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).
Owner
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: