Lunar Sample 61016, better known as "Big Muley", is a lunar sample discovered and collected on the Apollo 16

Apollo 16

Young and Duke served as the backup crew for Apollo 13; Mattingly was slated to be the Apollo 13 command module pilot until being pulled from the mission due to his exposure to rubella through Duke.-Backup crew:...

 mission in 1972 in the Descartes Highlands

Descartes Highlands

The Descartes Highlands is an area of lunar highlands located on the near side that served as the landing site of the American Apollo 16 mission in early 1972...

. It is the largest sample returned from the Moon

Moon

The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 as part of the Apollo program. The rock, an 11.7 kilogram breccia

Breccia

Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix, that can be either similar to or different from the composition of the fragments....

 consisting mainly of shocked

Shock (mechanics)

A mechanical or physical shock is a sudden acceleration or deceleration caused, for example, by impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation....

 anorthosite

Anorthosite

Anorthosite is a phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar , and a minimal mafic component...

 attached to a fragment of troctolitic

Troctolite

Troctolite is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with variable minor pyroxene. It is an olivine-rich, pyroxene-depleted relative of gabbro. However, unlike gabbro, no troctolite corresponds in composition to a...

 "melt rock", is named after Bill Muehlberger, the Apollo 16 field geology team leader.

Description

Big Muley was discovered on the eastern rim of Plum Crater in the Descartes highlands of the Moon. The rock's cosmic ray

Cosmic ray

Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...

 exposure age has been found to be about 1.8 million years, linking it to ejecta, or debris, from the impact that formed South Ray Crater, another crater in the vicinity of the Apollo 16 landing site.

The rock's age has been estimated since 1980 to be approximately 3.97 ± 0.25 billion years. The rock has been highly shocked throughout its history, as indicated by the fact that most of the rock's plagioclase

Plagioclase

Plagioclase is an important series of tectosilicate minerals within the feldspar family. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a solid solution series, more properly known as the plagioclase feldspar series...

 content was converted to maskelynite

Maskelynite

Maskelynite is a glassy phase found in some meteorites and meteorite impact craters. Typical samples are similar in composition to plagioclase feldspar, and revert to that mineral when melted and recrystallized. It was named after British geologist M.H.N...

 and/or plagioclase glass

Glass

Glass is an amorphous solid material. Glasses are typically brittle and optically transparent.The most familiar type of glass, used for centuries in windows and drinking vessels, is soda-lime glass, composed of about 75% silica plus Na2O, CaO, and several minor additives...

.

External links

• Lunar Sample 61016 — Images of Big Muley