GLG 301 Lecture Notes - Lecture 4: Sedimentary Rock, Protolith, Amphibolite
Document Summary
Some on land (terrestrial), some in lakes/rivers/oceans (lacustrine, marine, or sub- aqueous ) Form in a diverse variety of environments. Gneissic foliation: planar structures, due to mineral bonding. Changes in the minerals present and their orientations due to heat, pressure, or chemical changes due to fluids (metasomatism) What you get depends on what you start with (protolith - original rock) Pressure will reorient mineral growth or deform pre-existing ones. Rhyolite, granite, basalt - schist - gneiss. Refers to the amount of metamorphism (dependent on increasing pressure and temperature): Metamorphic grades are defined by characteristic minerals that are present. Low pressure/temperature conditions result in chlorite or serpentine, resulting in. High pressure conditions produce a blueschist due to a variety of amphibole. Mineralogy depends on the minerals in the protolith. Any kind of rock can turn into any kind of other rock. The rock record tells us the history of a region at different time scales.
