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  2. Gneiss - Wikipedia

    en.wikipedia.org/wiki/Gneiss

    Augen gneiss, from the German: Augen, meaning "eyes", is a gneiss resulting from metamorphism of granite, which contains characteristic elliptic or lenticular shear-bound grains (porphyroclasts), normally feldspar, surrounded by finer grained material. The finer grained material deforms around the more resistant feldspar grains to produce this ...

  3. Metamorphism - Wikipedia

    en.wikipedia.org/wiki/Metamorphism

    The solidus temperature depends on the composition of the rock, the pressure, and whether the rock is saturated with water. Typical solidus temperatures range from 650 °C (1,202 °F) for wet granite at a few hundred megapascals (MPa) of pressure [9] to about 1,080 °C (1,980 °F) for wet basalt at atmospheric pressure. [10]

  4. Granulite - Wikipedia

    en.wikipedia.org/wiki/Granulite

    The granites pass into gneiss and granulite; the gabbros into flaser gabbro and amphibolite; the slates often contain andalusite or chiastolite, and show transitions to mica schists. At one time these rocks were regarded as Archean gneisses of a special type.

  5. Metamorphic rock - Wikipedia

    en.wikipedia.org/wiki/Metamorphic_rock

    They can be divided into a lower group of metabasalts, including rare metakomatiites; a middle group of meta-intermediate-rock and meta-felsic-rock; and an upper group of metasedimentary rock. [ 38 ] The greenstone belts are surrounded by high-grade gneiss terrains showing highly deformed low-pressure, high-temperature (over 500 °C (932 °F ...

  6. S-type granite - Wikipedia

    en.wikipedia.org/wiki/S-type_granite

    Figure 8. Cross-polarized light photomicrograph of a "pressure-quench" texture in sample Cv-114 from the S-type Strathbogie Granite. A rapid change in pressure, from loss of volatile components (e.g., dissolved water in the melt) during crystallization can lead to a period of rapid crystallization.

  7. Peninsular Gneiss - Wikipedia

    en.wikipedia.org/wiki/Peninsular_Gneiss

    The earliest rock was a dark coloured amphibolite which was converted into grey biotite gneiss during migmatization. The grey biotite gneiss during migmatization was first intruded by grey porphyritic granite and later by pink granites. Pegamatities of several generations have traversed all these rocks. Gneissic exposure at the Lalbagh hillock

  8. Lewisian complex - Wikipedia

    en.wikipedia.org/wiki/Lewisian_complex

    Geological map of the Hebridean Terrane showing distribution of rocks of the Lewisian complex Undeformed Scourie dyke cutting Lewisian Gneiss, about 1.6 km west of Scourie Scourie dykes (now foliated amphibolites) cutting grey gneiss of the Scourie complex, both deformed during the Laxfordian tectonic event and cut by later (unfoliated) granite veins - road cutting on the A838 just north of ...

  9. Woodstock Quartz Monzonite - Wikipedia

    en.wikipedia.org/wiki/Woodstock_Quartz_Monzonite

    This mass of granite, which is evidently intruded into the gneisses, is entirely enveloped by them and sends no dikes or apophyses into the surrounding rock. That the gneiss is really older than the granite is shown by the great number of inclusions found within the latter. These are chiefly of gneiss, and they occur often in huge irregular ...