15357 (9) Impact Melt
Collection:
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Fact sheet

15357 (9) Impact Melt

15357 is a rake sample that can be compared with 15356 and 15359. It is a poikilitic impact melt with mineral clasts that may be a rare piece of the Imbrium melt sheet. The texture is micropoikilitic with pyroxene (pigeonite) oikocrysts about 100 microns across containing small stubby plagioclase crystals. Some coarser (50 microns) plagioclase crystals are interoikocryst or penetrate oikocrysts. Ilmenite is elongated but not bladed. Interstitial silicic glass with apatite is common. Clasts are larger, more varied, and more abundant that in 15356. Rotation 1 shows clasts of pyroxene and plagioclase feldspar, whereas rotation 2  mainly shows a basalt clast and a small devitrified glass fragment.

The sample weighed 11.8 grams before analysis and has been dated at 3.85±32 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 15 landing site was in the Apennine Highlands, and close to Hadley Rille — a long, narrow winding valley. Approximately 76 kg of lunar material, including soil, rock, core-tube and deep-core samples, were returned to Earth.

This mission was the first flight of the Lunar Roving Vehicle which allowed the astronauts to venture further from the Lunar Module than in previous missions. During three periods of extravehicular activity, or EVA, on July 31st, and August 1st and 2nd, Scott and Irwin completed a record 18 hours, 37 minutes of exploration, travelling 17.5 miles, in the first car that humans had ever driven on the Moon.

Apollo 15 was launched on 26 July 1971.

Sample details

Collection: Apollo 15
Type
metamorphic
Rock-forming mineral
pyroxene
plagioclase
feldspar
glass
Accessory minerals
ilmenite
troilite
apatite
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: