enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Porphyritic - Wikipedia

    en.wikipedia.org/wiki/Porphyritic

    Porphyritic texture in a granite. This is an intrusive porphyritic rock. The white, square feldspar phenocrysts are much larger than crystals in the surrounding matrix; eastern Sierra Nevada, Rock Creek Canyon, California. A porphyritic volcanic sand grain, as seen under the petrographic microscope. The large grain in the middle is of a much ...

  3. Igneous textures - Wikipedia

    en.wikipedia.org/wiki/Igneous_textures

    Porphyritic textures develop when conditions during the cooling of magma change relatively quickly. The earlier formed minerals will have formed slowly and remain as large crystals, whereas, sudden cooling causes the rapid crystallization of the remainder of the melt into a fine-grained (aphanitic) matrix .

  4. Porphyry (geology) - Wikipedia

    en.wikipedia.org/wiki/Porphyry_(geology)

    "Imperial Porphyry" from the Red Sea Mountains of Egypt A waterworn cobble of porphyry Rhyolite porphyry from Colorado; scale bar in lower left is 1 cm (0.39 in). Porphyry (/ ˈ p ɔːr f ə r i / POR-fə-ree) is any of various granites or igneous rocks with coarse-grained crystals such as feldspar or quartz dispersed in a fine-grained silicate-rich, generally aphanitic matrix or groundmass.

  5. Chondrule - Wikipedia

    en.wikipedia.org/wiki/Chondrule

    More commonly, chondrules display what is known as a porphyritic texture. In these, grains of olivine and/or pyroxene are equidimensional and sometimes euhedral. They are named on the basis of the dominant mineral, i.e. porphyritic olivine (PO), porphyritic pyroxene (PP), and porphyritic olivine-pyroxene (POP). It seems likely that these ...

  6. Phenocryst - Wikipedia

    en.wikipedia.org/wiki/Phenocryst

    Aphyric rocks are those that have no phenocrysts, [3] or more commonly where the rock consists of less than 1% phenocrysts (by volume); [4] while the adjective phyric is sometimes used instead of the term porphyritic to indicate the presence of phenocrysts. Porphyritic rocks are often named using mineral name modifiers, normally in decreasing ...

  7. Porphyry - Wikipedia

    en.wikipedia.org/wiki/Porphyry

    Porphyry (geology), an igneous rock with large crystals in a fine-grained matrix, often purple, and prestigious Roman sculpture material Shoksha porphyry, quartzite of purple color resembling true porphyry mined near the village of Shoksha, Karelia, Russia

  8. Matrix (geology) - Wikipedia

    en.wikipedia.org/wiki/Matrix_(geology)

    Igneous rock, with gray groundmass and white phenocrysts marked. Orthoclase phenocrysts within a finer-grained matrix of a granite porphyry. The matrix or groundmass of a rock is the finer-grained mass of material in which larger grains, crystals, or clasts are embedded.

  9. Glomeroporphyritic - Wikipedia

    en.wikipedia.org/wiki/Glomeroporphyritic

    In geology, the term glomeroporphyritic (also cumulophyritic) refers to the grouping of phenocrysts, not necessarily of the same mineral, into distinct clusters within porphyritic igneous rocks. [ 1 ]