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| The Overall study of rocks. |
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| The study of the description and classification of rocks (aka lithology). |
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| The study of the histories and origins of rocks. |
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| Mineralogical Composition |
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| The composition of a rock with respect to the minerals in it? |
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| List of minerals observed and their volume percentages. |
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| List of hypothetical minerals and their percentages calculated from whole rock geochemistry. |
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| Whole Rock Chemical Composition |
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| Concentrations of the major, minor and trace elements. |
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| Siderophiles ("Iron-Loving") |
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Definition
| exhibit a weak affinity to both oxygen and sulfur. Siderophiles have an affinity for iron and a distinguishing characteristic of siderophiles is that they exhibit high solubility in molten iron. Siderophile elements generally have a low reactivity and exhibit an affinity to form metallic bonds. As a result, siderophiles are most often found in their native state. Not abundant in the core or mantle, most siderophiles are thought to be richest at Earth's core. Platinum (Pt) group metals, including Ruthium (Ru), Rhodium (Rd), Palladium (Pd), Osmium (Os), and Iridium (Ir), show exhibit a strong siderophile tendency. |
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| Chalcophiles ("Sulfur-Loving") |
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Definition
| have a high bonding affinity—usually in the form of covalent bonds—with sulfur, and are, accordingly, usually abundant in sulfides. Chalcophiles also exhibit a bonding affinity with selenium, tellurium, arsenic, and antimony and therefore also exhibit high levels of derivatives of these elements. When sulfur is abundant, chalcophile elements readily form sulfide minerals as they precipitate from the magma. This process partially explains the formation of extensive deposits of iron-nickel-copper sulfides. |
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| Lithophiles ("Rock-Loving") |
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Definition
| have a high bonding affinity with oxygen. Lithophiles have an affinity to form ionic bonds and are represented by silicates (silicon and oxygen) in the crust and mantle. Other lithophile elements include magnesium, aluminum, sodium, potassium, iron, and calcium. |
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| Total Alkali vs Silica Classification |
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| The compositional range between end-member minerals that share the same basic chemical formula, but experience substitution of elements in one or more atomic sites. |
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| An equation relating the nuber of components, the phases, and the veriance of a system: F = C - P + 2, where F = # of degrees of freedom, C = # of components, and P = # of phases. |
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Definition
| A homogeneous material that, because of its physical properties, can be separated by mechanical means from other phases with which it may occur. |
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| A chemical species (e.g. SiO2, OH-). In the phase rule, the # of components is defined as the smallest number of chemical species needed to define the compositions of all phases in the system. |
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| The # of variables (e.g. pressure and temperature) that can be independently changed without altering the state of the system. |
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| neither P or T can be changed |
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| either P or T can be changed independently, but to maintain the state of the system, there must be a corresponding change in the other variable |
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| both P and T are free to change independently without changing the state of the system |
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| It specifies the maximum temperature at which crystals can co-exist with the melt in thermodynamic equilibrium. Above the liquidus temperature the material is homogeneous. Below the liquidus temperature more and more crystals begin to form in the melt if one waits a sufficiently long time, depending on the material. |
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Definition
| The solidus quantifies the temperature at which melting of a substance begins, but not necessarily the substance is melted completely, i.e., the solidus is not necessarily a melting point. |
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Definition
An invariant point representing the melt composition and the lowest temperature at which a mixture of two or more solid phases will melt. Initial melting does not change the composition o the solid phases. The eutectic point is the lowest point on the liquidus curve.
Of, relating to, or formed at the lowest possible temperature of solidification for any mixture of specified constituents. |
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Definition
An inflection point on a liquidus curve representing the melt composition and temperature at which a discontinuous reaction (i.e. inconguent melting or crystallization) occurs.
A reaction where a solid phase and liquid phase will together form a second solid phase at a particular temperature and composition. |
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| The line on a phase diagram that separates two separate phase fields and represents the line of liquid composition, or the temperature - composition curve, along which two solid phases crystallize simultaneously. |
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| Equilibrium Crystallization |
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Definition
| Crystallization where the crystals are not fractionated out when crystallization occurs. |
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| Fractional Crystallization |
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Definition
| Crystallization where the crystals are fractionated out when crystallization occurs. |
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| Gravitational Differentiation |
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Definition
| A process of magmatic differentiation in which crystals are separated from the liquid by sinking (or flotation) due to the relatively higher (or lower) density of the crystals. |
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| A region separating two or more minerals consisting of the products of a reaction between them. |
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| Plane of Silica Saturation and Critical Plane of Silica Undersaturation |
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| Distribution Coefficient (Kd, "Bulk D", etc.) |
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Definition
| It lets you find out how compatible something is. |
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