Titus Salt is an man associated with the local area, though we are not here to discuss his history, we are here to look at his statue, and the geology of the stone that it is made of.
The statue is made of marble.
Marble is a metamorphic rock resulting from the recrystallization of limestone.Limestone is a sedimentary rock composed largely of the minerals calcite and/or aragonite, which are different crystal forms of calcium carbonate (CaCO3).
Marble is composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Heat and pressure over time cause the carbonate minerals to recrystallize into an interlocking mosaic of crystals, the different colours due to the various mineral impurities such as clay, silt and sand.
The resulting marble rock is typically composed of an interlocking mosaic of carbonate crystals. Primary sedimentary textures and structures of the original carbonate rock (protolith) have typically been modified or destroyed.
Pure white marble is the result of metamorphism of a very pure (silicate-poor) limestone or dolomite protolith. The characteristic swirls and veins of many colored marble varieties are usually due to various mineral impurities such as clay, silt, sand, iron oxides, or chert which were originally present as grains or layers in the limestone.
Green coloration is often due to serpentine resulting from originally high magnesium limestone or dolostone with silica impurities. These various impurities have been mobilized and recrystallized by the intense pressure and heat of the metamorphism.
Metamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure (temperatures greater than 150 to 200 °C and pressures of 1500 bars) causing profound physical and/or chemical change. The protolith may be sedimentary rock, igneous rock or another older metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and are classified by texture and by chemical and mineral assemblage (metamorphic facies). They may be formed simply by being deep beneath the Earth's surface, subjected to high temperatures and the great pressure of the rock layers above it. They can form from tectonic processes such as continental collisions, which cause horizontal pressure, friction and distortion. They are also formed when rock is heated up by the intrusion of hot molten rock called magma from the Earth's interior. The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides us with information about the temperatures and pressures that occur at great depths within the Earth's crust.
Some examples of metamorphic rocks are gneiss, slate, marble, schist, and quartzite.
There are two basic types of metamorphic rocks, these are known as 'Folidated' and 'Non-Foliated'. A Foliated metamorphic rock has a layered or banded appearance that is produced by exposure to heat and directed pressure a Non-foliated metamorphic rock is the opposite of this and does not have a layered or banded appearance.
Because of its specific colours and textural variations, marble is highly valued as a decorative stone.
This being an EarthCache, in order to log it, I ask that you answer the above questions. Please send them to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile.
(1) Are there any evidence of impurities on the statue, if so what colour are these?
(2) Is this a foliated or non foliated stone?
(3) Please describe the texture and colour of the stone. You will only be able to feel the base.