Mt Waldo is a small mountain about 1500' high in Knox country, Maine that is a geological formation known as a granite pluton. Please do not confuse this with Pluto the planet, or the dog from Disney!

So, what is a pluton and why did we write this paper? We are a group of people from a small enviromental college taking a core geology class and this is our final project. We hope you learn something and have some fun at the same time! Below are some terms and links along with some pictures that will help explain what Mt. Waldo is all about. CHEERS

Granite :a very hard natural igneous rock of visibly crystalline texture formed essentially of quartz, potassium feldspar, and sodium plagioclase, or albite, and used for building and for monuments.

Intrusive igneous rocks form by the solidification of magma below the Earth's surface. Extrusive igneous rocks form by the solidification of magma on the Earth's surface.The most common igneous rock structures are plutons, batholiths, stock, dikes, and sills. A pluton is a body of intrusive igneous rock, that have become solidified magma and are exposed for years in which erosion removes the overlying rocks

Mt. Waldo is a granite pluton that was mined to bulid Fort Knox, the first fort built of granite in Maine. Granite is an ideal building material.

Basically granite is strong and hard and because of its geological formation, which is condusive to building things with. It breaks in nice staight lines if you know what you are doing, Which the old time granite quarriers did very well. This is due to the fact that as granite is being formed, cleavage lines are being established in the rock.

Cleavage

The following is some information which might prove helpful in identifying and understanding cleavage. Mt. Waldo contains a lot of cleavage which is an even layering of rock.

The strength of bonding between different atoms can vary within a mineral structure. Weaker bonds may be aligned because of the mineral crystalline structure and constitute inherent planes of weakness. When these types of minerals are broken they have a tendency to split or cleave along the planes of bonding weakness. Minerals characterized by such orderly breakage are said to possess cleavage. This type of structural weakness is present in graphite. When graphite is broken, it will cleave along planes between the sheets of strongly bonded atoms. Within any specimen of graphite there are hundreds of thousands of potential cleavage planes. Collectively they define a cleavage direction.

The mineral halite also displays cleavage. When broken, grains split parallel to layers of constituent sodium and chlorine atoms. Because of a cubic internal order, there are different ways in which atom layers may separate. Thus halite has three different directions of cleavage which intersect at 90 degrees. Regardless of how often a piece of halite is broken, each fragment will be bounded by six cleavage planes, two from each of the three cleavage directions. Tiny cubes of table salt are an example of the repetition of this cleavage phenomenon.

Calcite is another mineral species which has three directions of cleavage. In contrast to halite, calcite? cleavage directions do not intersect at right angles and rhombohedral-shaped fragments are produced when calcite is broken.

Minerals may have 1,2,3,4, or 6 directions of cleavage. For any particular mineral species the number of cleavage directions and the angles between intersecting cleavage planes are constant. Because of this consistency, cleavage is a physical property which is useful in mineral identification. Although cleavage is most easily seen by breaking a sample, it is usually not necessary to do so. Careful examination of previously broken surfaces typically reveals the presence or absence of cleavage. Cleavage planes may be recognized because they are generally smooth surfaces which reflect light like a mirror. Cleavage planes frequently occur in close-spaced groups, producing an overall step-like appearance. Rotation of such a sample in direct light will show that each small cleavage plane has an intensity of light reflection which is similar to that of larger cleavage planes which bound the mineral fragment.

When describing a mineral cleavage always include:
1. The number of cleavage directions.
2. The angles between cleavage directions.
3. The smoothness (perfection) of cleavage planes within each cleavage direction.

This page developed by:

Leo St. Peter
John Barnes
Becca Coles
Zack