Meta Rocks - iii.The loss of volatiles is important III...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
I) Meta Rocks a. Formed by the alteration of rocks i. Changes result in the restoration of equilibrium under new environmental conditions ii.The kind of rock being metamorphosed (i.e. parent rock) is the most important factor in determining what meta rock will be formed. 1. Changes occur solid to solid b. Scales of metamorphism i. Batholith contacting host rock ii.Produces broad bands of meta (several km wide) c. Contact metamorphism i. Dike intrudes host rock ii.Forms a metamorphosed aureole (“baked zone”) around intrusion. II) Metamorphic processes a. Temperature i. Measurement of kinetic energy of molecules. ii.Chemical reactions take place more easily at higher temperatures. iii.Water drive off b. Pressure i. Force/unit area 1. Changes rock texture ii.Higher pressure can be achieved by 1. Deep burial 2. Stress [directional pressure] c. Metasomatism i. Chemical action of pore fluids. ii.Rextallization is accompanied by some chemical change.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Background image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: iii.The loss of volatiles is important III) Effects of metamorphism a. Recrystallization i. Pre-metamorphic minerals are transformed into larger crystals. b. Foliation i. The parallel alignment of platy minerals c. Chemical recombination i. Two or more minerals in the host rock recombine to form a new mineral without the addition of any new material. d. Chemical replacement i. New material is combined with host rock minerals to produce a new mineral. e. Index minerals i. Minerals that define specific temperatures and pressure of formation. IV) Metamorphic textures\ a. Foliation i. Slate 1. Very fine cleavage 2. Fissile a. Break easily along cleavage plane ii.Phyllite 1. Waxy/greasy look on the surface. iii.Schist 1. Coarse foliation a. Visible micas iv.Gneiss 1. Very coarse foliation 2. Light and dark bands in rock v.Marble 1. Metamorphosed limestone vi.Quartzite 1. Metamorphosed sandstone...
View Full Document

{[ snackBarMessage ]}

Page1 / 2

Meta Rocks - iii.The loss of volatiles is important III...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online