is diabase intrusive or extrusive

Intrusive, or plutonic, igneous rock forms when magma remains inside the Earth's crust where it cools and … Preliminary QAPF classification of: a – intrusive rocks; b – extrusive rocks. Intrusive. Quartz, Potassium-Felspar, Plagioclase Fledspar, Biotite Mica & Amphibole ... Diabase. Intrusive Igneous Rock . Properties of Igneous Rocks. Its principal minerals are feldspars, quartz, and mica. These types of rock include diabase, quartz-dolerite, micro-granite and diorite. Non-vesicular. Diabase: A hand specimen of diabase approximately ten centimeters across. can be intrusive or extrusive Can be fine or coarse grained* mafic. Coarse grained. Examples of intrusive igneous rocks are diorite, gabbro, granite, pegmatite, and peridotite. Basaltic Glass. Whereas plutonic rocks form continents, basalt lies in the crust underneath the oceans. Figure 4. Extrusive igneous rocks erupt onto the surface, where they cool quickly to form small crystals.

Figure 01: Igneous Rock. 2 Extrusive igneous rocks. Pyroxene, Amphibole, possibly Biotite and/or Olivine. As an example, a rock with the same composition could be called gabbro if it were plutonic, diabase if it were intrusive, or basalt if it were extrusive. Basalt Igneous rock Composition Mafic: plagioclase, amphibole, and pyroxene, sometimes feldspathoids, or olivine. This rock's name (Diabase) is defined by it's medium grained size crystals. The bottom salt-and-pepper colored portion is a polished surface displaying the plagioclase (white) and pyroxene (black) minerals that make up this specimen of an intrusive igneous rock. It is equivalent in composition to the coarse grained intrusive rock Gabbro and to the fine grained extrusive rock Basalt.. These rocks are in many ways similar to other intrusive rocks, but have intermediate grain sizes and textures, generally half way between those found in extrusive and other types of intrusive rocks. Intrusions are formed inside country rock which prevents the magma (=molten rock) intrusion from cooling quickly. Surrounded by pre-existing rock (called country rock), the magma cools slowly, and as a result these rocks are coarse grained. See igneous rocks are classified into extrusive and intrusive categories. Diabase is composed of plagioclase feldspar (mostly labradorite) and pyroxene ().The crystals that make up dolerite are usually visible to the naked eye, but sometimes porphyritic rocks of basaltic composition with pyroxene and especially plagioclase phenocrysts are also named that way. (after Le Maitre, 2005) Once you have determined the mineral assemblage of a rock, you can use the appropriate (intrusive or extrusive) QAPF chart to name it (fig. Greater then 95% of Diabase is composed of 2 minerals. Dark colored diabase dikes intrude through light colored granite at Acadia National Park, Maine. So, an extrusive igneous rock, is in the extrusive category. The Jurassic age York Haven Type Diabase is what forms the Monocacy Hill intnlsion. Extrusive. Basalt is a mafic extrusive igneous rock formed from the rapid cooling of lava rich in magnesium and iron exposed at or very near the surface of a terrestrial planet or a moon. 4a, b). Extrusive rocks have very small, almost microscopic crystals. Intrusive rocks are formed when magma cools underneath Earth’s surface. They contain less than 45 percent silica, and are believed to originate from the mantle. basalt-exrusive obsidian-extrusive pumice-extrusive granite-Intrusive Extrusive means its on the surface (on the ground). 1. Each kind of texture has a variety of different characteristics that make them unique. Extrusive… Felsic. NPS photo by Georgia Hybels. Intrusive igneous rocks crystallize below Earth's surface, and the slow cooling that occurs there allows large crystals to form.

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