15386 (46) KREEP Basalt
Click the microscope button to view a thin section for this sample.
Click the microscope button to view a thin section for this sample.

Fact sheet

15386 (46) KREEP Basalt

15386 is the largest sample of pristine KREEP basalt in the Apollo collection. By pristine we mean that it is lacking in meteoritical siderophiles (Ir, Re, Au etc), and hence not contaminated by meteorite debris. Thus it is thought to represent an indigenous lunar volcanic melt derived from the lunar interior. Plagioclase laths are surrounded by interstitial pyroxene. The cores of pyroxene crystals are Mg-rich orthopyroxene. They are surrounded (overgrown) by pigeonite with patches or rims of subcalcic augite.The mesostasis has significant cristobalite (10%), ilmenite plates (3%), and minor phosphate, metallic iron and troilite. Rotation 2 shows one of the interstital melt pockets enriched in these minerals. 

The sample weighed 7.5 grams before analysis and has been dated at 3.85±0.08 billion years (Sm/Nd).

Our sample has been used for laser-ablation analysis and displays many circular black pits where material has been removed. It has also been gold coated for SEM analysis and although most gold has been cleaned off, some remains in fractures.

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

KREEP is an acronym built from the letters K (the atomic symbol for potassium), REE (Rare Earth Elements) and P (for phosphorus). It is a geochemical component of some lunar impact breccia and basaltic rocks.

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
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: