What are AFM diagrams?
The AFM diagram is a ternary plot used to show the relative proportions of the oxides of alkalis (A), iron (F), and magnesium (M) in igneous rocks. The components of the diagram are thus A (Alkalis: Na2O + K2O), F (FeO & Fe203), and M (MgO).
What is ACF diagram?
ACF diagram A three-component, triangular graph used to show how metamorphic mineral assemblages vary as a function of rock composition within one metamorphic facies. Besides SiO 2, the five most abundant oxides found in metamorphic rocks are Al 2O 3, CaO, FeO, MgO, and K 2O.
What is Chemographic diagram?
Minerals and rocks have chemical compositions that comprise some of the most important data for phase equilibria studies. Important relationships among rocks and minerals can be discovered or demonstrated by the construction of composition diagrams (also called chemographic diagrams) to display the data.
What is Chemographic projection?
Chemographic projections are often used in metamorphic petrology to plot complex compositions on two-dimensional triangular diagrams. A popular chemographic projection for metapelites is the AFM diagram, which represents Al2O3, FeO, and MgO at its corners.
What is a Harker diagram?
Harker diagram (variation diagram) A diagram that shows the amount of each of the chemical constituents of a rock as a proportion of the main ingredient (usually silica).
What is a pelitic rock in geology?
A pelite (Greek: pelos, “clay”) or metapelite is a metamorphosed fine-grained sedimentary rock, i.e. mudstone or siltstone.
What is metamorphic phase rule?
Since metamorphism usually involves long periods of geologic time, most metamorphic rocks represent an equilibrium mineral assemblage. The Phase Rule for Metamorphism. Recall that the phase rule states that. F = C + 2 – P.
Why is AFM useful?
The AFM has several advantages over electron microscopy in the study of biological materials, including the ability to image in liquid with minimal sample preparation (no labeling, fixing, or coating). The AFM also allows the topographic characterization of surfaces at resolutions not achievable by optical microscopy.
What is variation diagram?
[‚ver·ē′ā·shən ‚dī·ə‚gram] (petrology) A diagram constructed by plotting the chemical compositions of rocks in an igneous rock series in order to show the genetic relationships and the nature of the processes that have affected the series. Also known as Harker diagram.
How is CNK calculated?
A/CNK [A/CNK= molar ratio Al 2 O 3 / (CaO+Na 2 O+K 2 O) and A/NK= molar ratio Al 2 O 3 /(Na 2 O+K 2 O)]. The QGC rocks have predominantly metaluminous compositions. Symbols as in Fig. 3.
What are argillaceous rocks?
Argillaceous minerals are minerals containing substantial amounts of clay-like components (Greek: ἄργιλλος = clay). Argillaceous components are fine-grained (less than 2 μm) aluminosilicates, and more particularly clay minerals such as kaolinite, montmorillonite-smectite, illite, and chlorite.
What does Gibbs phase rule state?
The Gibbs phase rule p+n=c+1 gives the relationship between the number of phases p and components c in a given alloy under equilibrium conditions at constant pressure, where n is the number of thermodynamic degrees of freedom in the system.
What is the major working principle of AFM?
The Underlying Principle of AFM AFM microscopes operate on the principle of surface sensing using an extremely sharp tip on a micromachined silicon probe. This tip is used to image a sample by raster scanning across the surface line by line, although the method varies dramatically between distinct operating modes.