15661 (13) Porphyritic Olivine Basalt
Collection:
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Fact sheet

15661 (13) Porphyritic Olivine Basalt

15661 was collected as a rake sample. It is vesicular, vuggy and has a few olivine phenocrysts; typical of olivine-normative basalts. 15661 is a fine- to medium-grained microgabbroic mare basalt with about 60% pyroxene. Rare olivine phenocrysts reach about 1.5mm, are anhedral (see rotation 2), and contain crystallized silicate melt inclusions. Most pyroxene and olivine crystals are less than 0.5mm across. Pyroxene and olivine tend to be granular and the plagioclase feldspar forms subhedral hollow laths. A few variolitic areas are present. Chromite forms cores to some ulvospinel. Cristobalite, fayalite, ilmenite, troilite and some glass is also present. Rotation 1 shows an interstitial melt pocket.

The sample weighed 5.9 grams before analysis and has not been dated.

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
igneous
Rock-forming mineral
olivine
pyroxene
plagioclase
feldspar
Accessory minerals
fayalite
cristobalite
chromite
ulvospinel
ilmenite
troilite
metallic iron
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: