What is tie line flip reaction?
Tie line flip reactions involve two phases becoming stable together that were previously unstable together, and vice versa. As with terminal reactions, they may be solid-solid reactions or may involve a fluid phase. An example of a tie-line flip reaction is: chlorite + garnet = biotite + staurolite.
What is net transfer reaction?
Net-transfer reactions involve the breakdown of preexisting mineral phases and corresponding nucleation and growth of new phases. (Nucleation is the process in which a crystal begins to grow from one or more points, or nuclei.)
What is metamorphic reaction mechanism?
A metamorphic reaction is a chemical reaction that takes place during the geological process of metamorphism wherein one assemblage of minerals is transformed into a second assemblage which is stable under the new temperature/pressure conditions resulting in the final stable state of the observed metamorphic rock.
What is the discontinuous reaction series?
A reaction series in which early-formed crystals react with later liquid by means of abrupt phase changes; e.g., the minerals olivine, pyroxene, amphibole, and biotite form a discontinuous reaction series.
How many minerals are involved in a normal Univariant reaction?
Normal univariant reactions, then, involve 5 phases. For example, the (Di) reaction involves four minerals and a fluid. Invariant points involve 6 phases, and 4 phases are stable in each divariant field.
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 the difference between the continuous and discontinuous series of Bowen’s reaction series?
The continuous branch describes the evolution of the plagioclase feldspars as they evolve from being calcium-rich to more sodium-rich. The discontinuous branch describes the formation of the mafic minerals olivine, pyroxene, amphibole, and biotite mica.
What is brown reaction Series?
Bowen’s Reaction Series describes the temperature at which minerals crystallize when cooled, or melt when heated. The low end of the temperature scale where all minerals crystallize into solid rock is approximately 700°C (158°F).
Where does sillimanite occur?
It is sometimes used as a gem, as brown chatoyant crystals and aggregates are known from several localities, among them southern India and Sri Lanka. The finest light blue, transparent crystals are found in the gem sands of Sri Lanka and Burma.
What does sillimanite mean?
Definition of sillimanite : a brown, grayish, or pale green mineral that consists of an aluminum silicate in orthorhombic crystals often occurring in fibrous or columnar forms.
What is Bowens reaction principle?
Bowen’s reaction principle A concept, first propounded in 1928 by Norman Bowen, which explains how minerals can respond to the changing equilibrium conditions when a magma is cooled, by either a continuous, diffusion-controlled exchange of elements with the magma or discontinuous melting of the mineral.
How do you explain Bowen’s reaction series?