77135 (116) Poikilitic Impact-Melt Breccia
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Click the microscope button to view a thin section for this sample.

Fact sheet

77135 (116) Poikilitic Impact-Melt Breccia

77135 was sampled as green-grey breccia. It is an impact melt breccia remarkably similar in textural appearance and chemical composition to 76015. In fact, sample 77135 is a fine-grained, grey, vesicular, fragment-laden, crystalline matrix breccia. It has two parts: a larger, highly vesicular part which includes clasts of recrystallized troctolitic anorthosite and a smaller less vesicular part which includes recrystallized troctolitic breccia. Our thin section samples a pyroxene-rich region. The coarse-grained matrix of 77135 consists predominantly of poikilitic pyroxene (mostly pigeonite with minor augite) enclosing subhederal to euhedral plagioclase and minor olivine. Borders between pyroxene oikocrysts contain granular olivine, ilmenite plates and rods and mesostasis.The finer-grained matrix commonly surrounds or is adjacent to large lithic clasts. The matrix of the finer fraction also consists predominantly of poikilitic pyroxenes enclosing plagioclase. Intergrowths of olivine and plagioclase form aggregates approximately the same size as pyroxene oikocrysts. There appears to be more olivine, less pyroxene and less vesicles in the finer-grained lithology. Rotation 1 shows a shocked olivine clast and rotation 2 shows a region containing two dark, glassy aphanitic clasts and a few shocked pyroxene clasts. Metallic iron and less common troilite are visible in reflected light.

The sample weighed 337.4 grams before analysis and has been dated at 3.94±0.04 billion years.

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

About this collection

Apollo 17, the final manned landing mission, had two objectives: to obtain samples of ancient rocks from the lunar highlands and to look for evidence of younger volcanic activity on the valley floor.

This small Collection contains material deriving from both periods, including igneous rocks around 4.3 billion years old from the lunar highlands as well as younger volcanic samples dating from about 3.6 billion years ago.

Apollo 17 was launched on 7 December 1972.

Sample details

Collection: Apollo 17
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: