Planetary Geology on Earth: Moonstone EarthCache
Hidden : 3/3/2016
Difficulty:
1.5 out of 5
Terrain:
1.5 out of 5

Size: Size: other (other)

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Geocache Description:

-- THIS IS AN EARTHCACHE, PLEASE READ BELOW FOR LOGGING REQUIREMENTS --


A quick summary:

  • These rocks are not from the moon - but they are the same type of rock that makes up the majority of the moon's surface (Anorthosite)
  • The Moon River was not named for the moon, but for the ojibwa name for moose - "moonz-ziibi"
  • The Cheese content of the moon is presently 0

Contrary to popular belief, the moon is not made of cheese! Neil Armstrong and Buzz Aldrin collected 21.5 kg (47.5 lb.) of lunar material for return to Earth. During subsequent Apollo surface excursions, 2,415 samples weighing 382 kg (842 lb.) were collected, the majority by Apollo 15, 16, and 17. It turns out that the moon's bright areas are mostly composed of Anorthosite - a mineral commonly found in Northern Ontario, and through out the Canadian Shield.

We also know it has taken Sudbury a long time to shed its lunar image. During the Apollo exploration program, NASA (North American Space Agency) astronauts trained in Sudbury to become familiar with rare rock formations produced by large meteorite impacts. However, the popular misconception that they were visiting the "Nickel City" because it resembled the lifeless surface of the moon was then initiated.

In reality it was the geology of northern Ontario that was important and remains so. Particularly, the Apollo 16 astronauts were the first to visit the Sudbury basin for their mission. They participated in an extensive training program that included several field geology trips to introduce the astronauts to concepts and techniques they would use on the lunar surface. During these trips, the astronauts visited and provided scientific descriptions of geologic features they were likely to encounter. Geologists chose the Sudbury area because of a 97 km (60 miles) wide crater created about 1.6 million years ago by a large meteorite (see Earthcache here). During the training exercises the astronauts did not wear spacesuits, but carried radio equipment to converse with each other, practicing procedures they would use on the lunar surface.



Anorthosite is a calcium rich feldspar and can also be processed to produce a raw material for the manufacture of reinforcing glass fibre and other industrial products such as mineral fillers. Anorthosite is an unusual mafic igneous intrusive rock consisting of greater than 90% plagioclase feldspar. A 417 tonne of pure anorthosite product sample was used in a furnace trial to evaluate its performance as an alternative raw material for certain fibreglass applications offering potential product quality, cost and environmental benefits including reduction of furnace greenhouse gas emissions.

Whether occurring on the Earth or on the Moon, anorthosite is formed by the crystallization of plagioclase feldspar from a cooling body of molten magma. In the case of the Moon, shortly after its giant impact formation early in the history of the Solar System, it was so tremendously hot that the entire planet was covered by a deep molten magma ocean. As the Moon subsequently cooled and began to solidify, the plagioclase slowly crystallized at the top to form the anorthosite of the primitive lunar crust. Subsequent geologic activity on the Moon produced the dark-colored basaltic lava flows that we see today as the lunar maria, but the bulk of the Moon's primitive anorthosite crust remains visible as the light-colored lunar highlands. The Apollo astronauts returned samples of this ancient anorthosite that dates back over 4 billion years to the earliest history of the Solar System.



The Moon River anorthosite is pervasively layered. The layers consist of granoblastic white anorthosite layers ranging from 1 to 25 cm in thickness. These alternate with mafic layers which range from 1 to 10 cm in thickness. The river itself was not named for the lunar geology however - The name of the river is thought to be derived from its Ojibwa name moonz-ziibi, which means "moose river".

The Moon River anorthosite is very clean. The feldspar is almost white and is free of iron oxide inclusions. Although it is commonly sercitized, the flake size of the sericite appears to be sufficiently fine that it may not present a problem in screening. The feldspar is white and is considered to have undergone a high degree of recrystallization. The anorthosite consists of labradorite crystals and laths. The plagioclase generally displays some degree of alteration to sericite.

Anorthosite is commonly used in Fibre Glass Manufacturing, and is a popular decorative stone for gardens and patios. It also has a high aluminum content, but requires highly caustic chemicals to seperate - making it a hard sell as an aluminum ore.

Logging Requirements
Please send a message to the cache owner with answers to the following questions:

  1. Walk to the GZ and study closely a bit of Anorthosite. What Colour is it?
  2. How large in mm would you estimate the crystals are ?
  3. There is a predominant mineral mixed into the Anorthosite. Characterize the colour and size of crystals - and if you know it - the name of the mineral
  4. Based on the content of Anorthite in Anorthosite and the chemical composistion of Anorthite, what component in Anorthosite has a potential large industrial potential?
  5. (Optional) Take a picture of your team and some moon (river) rock!

Additional Hints (No hints available.)



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