In the dimension stone industry, gabbro is sold under the name "black granite." Basalts are extrusive igneous rocks that cool quickly and have fine-grained crystals. So why do we see the slowly-cooled intrusive version on the continents, but the rapidly-cooled extrusive basalt in the oceans? Gabbro is a coarse-grained and usually dark-colored igneous rock. Gabbro is very similar to basalt in its mineral make up. Norite may be very similar to gabbro but contains orthopyroxene, not clinopyroxene. Gabbro with large augite phenocrysts embedded in white plagioclase. The extrusive (volcanic) equivalent of diorite is andesite. Is gabbro an intrusive or extrusive igneous rock? A hand sample from the Isle of Skye in Scotland (Black Cuillin Mountains). Gabbros are equivalent in composition to basalts. Diorite is usually lighter in color and contains more amphiboles than pyroxenes. Gabbro from the Troodos ophiolite in Cyprus. The process of formation of rocks is different for various rocks. It is the most abundant rock in the deep oceanic crust. Igneous rock composition chart: A chart that illustrates the generalized mineral composition of igneous rocks. Metamorphosed gabbro again. Width of sample 8 cm. However, only a thin surface veneer of oceanic crust is basalt. Hence, rock names like nepheline-bearing gabbro or olivine norite are possible. Basalts are extrusive igneous rocks that cool quickly and have fine-grained crystals. Le Maitre, R. W. (2005). It is composed mostly of the mineral plagioclase feldspar with smaller amounts of pyroxene and olivine. The most important mineral groups that make up this rock type are plagioclase and pyroxene. ultramafic. Troctolite contains mostly olivine and plagioclase, pyroxene again forms no more than 10% of the composition. 1. Gabbro is also used to make a number of rough-cut products such as curbing, ashlars, paving stones, and other products. Diorite is an intrusive plutonic rock with a composition that is intermediate between gabbro and granite. Width of sample 55 mm. Dolerite is medium-grained (Fig. It is gabbro in the strict sense because pyroxenes are monoclinic (they have inclined extiction). Preliminary QAPF classification of: a – intrusive rocks; b – extrusive rocks. Cooling Rate: fast, extrusive; Intrusive Equivalent: gabbro; Other Characteristics: weathers to red-brown, hematite/limonite/clay mixture ANDESITE. Formation Of Hypabyssal Rocks a sub category of the intrusive rock is the hypabyssal, or subvolcanic rock. Typical intrusive formations are batholiths, stocks, laccoliths, sills and dikes. Gabbroic rocks may contain small amounts of quartz (up to 5%). Gabbro will also be present in the deep plutons that form when magma chambers that feed basaltic eruptions crystallize. You can see a close-up view of gabbro toward the bottom of this page. La Palma is an oceanic island which is largely composed of volcanic rocks. only a thin surface veneer of oceanic crust is basalt. The deeper rocks of the oceanic crust are generally coarser-grained gabbro. (See composition chart on this page.). DIORITE. Rhyolite is very closely related to granite. If the magma forces its way to the surface, it is then called lava, which cools and hardens into extrusive rocks. We can tell the difference between intrusive and extrusive rock by noticing the texture of the rock surface. The most important minerals in the gabbron are plagioclase and pyroxene. Napp, Flakstadøya, the Lofoten Archipelago, Norway. Width of sample 15 cm. Igneous rocks with similar composition are basalt (extrusive equivalent of gabbro) and diabase (the same rock type could be named dolerite or microgabbro instead). Width of sample 11 cm. Polished gabbro is sold under the name "black granite" and is used for cemetery markers, floor tile, kitchen counter tops, facing stone, and other dimension stone uses. Yellow stripes in blue in the upper part of the image is an intergrowth of two pyroxenes (Opx in Cpx). This is the magma that did not break to the surface to cool as a basalt. Flakstadøya, the Lofoten Archipelago, Norway. Width of sample 12 cm. Granite is the most common intrusive igneous rock (see figure 2 for an example). Lava is magma that pushes up through the Earth's crust to the surface. When magma and lava cool and harden, they create igneous rocks. Tappeluft, Norway. It means that it formed as magma cooled slowly in the crust. Th… Crushed gabbro is used as
If quartz makes up more than 20%, then the rock is one of granitoids1. Gabbros are intrusive igneous rocks that cool slowly and have coarse-grained crystals. It is an intrusive rock. Gabbro is an intrusive igneous rock which is chemically equivalent to plutonic Basalt. The key difference between intrusive and extrusive rocks is that the intrusive rocks are formed from magma whereas the extrusive rocks are formed from lava. Basalt is an extrusive or intrusive rock that makes up most of the world's oceanic crust. Igneous Rocks: A Classification and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Igneous Rocks. Gabbros form in the crust. Gabbroic rocks are very hard and therefore suitable material for aggregate making. Gabbro is a coarse-grained, dark-colored, intrusive igneous rock. Plagioclase is sodium-calcium feldspar. Olivine And Py-roxene) And Plagioclase Would Be Classified As _____. Most of the earths surface is covered with rocks of various types. These rocks are composed of many distinct minerals. When magma cools within the Earth, the cooling proceeds slowly. Chemical composition of an average gabbro? Plagioclase is striped black-gray-white, pyroxene is colorful, there are some small olivine grains as well. How does an igneous rock that has both large and small mineral crystals form? A plutonis an igneous intrusive rock body that has cooled in the crust. Flakstadøya, the Lofoten Archipelago, Norway. It is a highly desirable rock that stands up to weathering and wear. The best way to learn about rocks is to have specimens available for testing and examination. Width of view 50 cm. and anywhere that a durable crushed stone is needed as fill. Width of sample 11 cm. Cambridge University Press. This mineral composition usually gives gabbro a black to very dark green color. Olivine (weathered orange iddingsite in this sample) may be an important constituent in these rocks. The colors are frequently dark gray, black and green. Gabbro and obsidian are the other important examples of this group. Divergent boundary: In the oceanic crust, basalt forms near the surface at a divergent boundary, but gabbro forms at depth from slow crystallization. “Olivine” should be added to the rock name if it contains more than 10% of it. Gabbro can be polished to a brilliant black luster. Rock & Mineral Kits: Get a rock, mineral, or fossil kit to learn more about Earth materials. Igneous rocks are called intrusive when they cool and solidify beneath the surface. Slow cooling allows time for large crystals to form, so intrusive igneous rocks have visible crystals. By studying this chart, you can see that gabbros and basalts are composed mainly of plagioclase feldspar, micas, amphiboles, and olivine. The term itself comes from Italy. The difference between the two rock types is their grain size. It contains more calcium than sodium in gabbro. Q. Intrusive igneous rocks cool slowly because they form underground. Gabbros are intrusive igneous rocks that cool slowly and have coarse-grained crystals. make cemetery markers, kitchen counter tops, floor tiles, facing stone, and other dimension stone
The word "basalt" is used because the rocks of the oceanic crust have a "basaltic" composition. Rocks form when mineral compounds react with heat, water or pressure. The presence of sodium-rich feldspar, oligoclase or andesine, in contrast to calcium-rich plagioclase, labradorite or bytownite, is the main distinction between diorite and gabbro. Ødegården Verk, Norway. Pyroxenite and other ultramafic rocks are darker- and diorite is lighter-colored. 4a, b). Intrusive igneous rocks cool underground. The classification scheme for gabbroic rocks without taking into account olivine and feldspathoids. A sample from Tangen, Hedmark, Norway. Diorite, gabbro, anorthosite — the three root names in this field are separated according to the colour index and the average composition of their plagioclase – anortho… Intrusive Igneous Rocks. It is usually black or dark green in color and composed mainly of the minerals plagioclase and augite. There are even more varieties possible. Black granite: A view of polished gabbro (labradorite). Gabbroic rock that contains almost no pyroxene is troctolite. (See illustration.). These rocks are all collectively called gabbroic rocks. Diallage is not defined as a mineral now, but it is monoclinic pyroxene anyway (either diopside or augite). Granite is a common intrusive rock. Rocks that contain more than 90% pyroxene is pyroxenite. Tremolite-scapolite rock. Granite is the most common type of land based intrusive rock, while gabbro is the type found most often underwater. Gabbro is a silica-poor intrusive igneous (plutonic) rock chemically equivalent to basalt. Extrusive igneous rocks are further divided into two major subcategories on the basis of the nature of the appearance of lavas on the earth’s surface e.g. Width of sample 7 cm. A sample from La Palma. Notice the large grains of pink, white, and gray minerals. Width of sample 8 cm. Width of sample 11 cm. Gabbro (red) on the QAPF diagram which is used to name most plutonic igneous rocks. If more than 5% of Cpx is replaced with orthorhombic pyroxene (orthopyroxene, abbreviated Opx), the rock is named gabbronorite. How do you know? Gabbros are equivalent in composition to basalts. These rocks may be extrusive or intrusive, depending on where the magma or lava crystallizes. There are five types of intrusive rocks, which are granite, pegmatite, gabbro, diorite and peridotite. Picture taken in a gabbro quarry in southeastern Norway. A sample from Tangen, Norway. bytownite) and pyroxenes (usually augite). Basalt is the most common extrusive rock whil… The former was altered to scapolite and the latter to hornblende. Extrusive Rocks. They are similar because gabbro has the same composition as basalt, they are different because basalt is an extrusive igneous rock, gabbro is an intrusive igneous rock. Slow cooling gives crystals a chance to grow. These colors are not real, they are caused by the interference between lightwaves. Unlike many other igneous rocks, gabbro usually contains very little quartz. The molten rock will crystalize and solidify giving the two basic groups of igneous rocks called Intrusive, formed under the earth, and Extrusive, formed above the earth. Intrusive rocks form plutons and so are also called plutonic. If there is more quartz present, the rock must be named quartz gabbro. Gabbroic rocks are usually equigranular (composed of similarly sized grains) mixtures of black, brown or greenish pyroxene and white, gray, or greenish plagioclase. porphyritic. Question: A Fine-grained, Extrusive (or Volcanic) Igneous Rock Composed Of Mainly Mafic Minerals (e.g. It is used for everything from crushed stone base materials at construction sites to polished stone counter tops and floor tiles. Learn about teaching plate tectonics. A pluton is an igneous rock body that forms within the crust. This rock was originally normal gabbro, but it has been metamorphosed by hot fluids that altered augite to similar but hydrated silicate mineral hornblende. Before we discuss the extrusive quality of basalt, it's important to understand that it's an igneous rock. Gabbro has a variety of uses in the construction industry. The area shown in this image is about 1/2 inch across. These rocks are formed because of the action of high pressure, high te… The most common use of gabbro is as a crushed stone or aggregate. : (i) Explosive type and (ii) Quiet type. Deep in the crust, magma cools slowly. At greater depth the cooling rate is slower, and large crystals have time to develop. Basalts are extrusive igneous rocks that cool quickly and have fine-grained crystals. The difference between the two rock types is their grain size. 4.19) intrusive equivalent of volcanic basalt or plutonic gabbro, and usually occurs as dykes (Fig. Gabbro is a dark-colored coarse-grained intrusive igneous rock. If more than 95% of the pyroxene is Opx, then we have norite. plagioclase often appear more. 4.20), sill and plugs.Dolerite is heavy with specific gravity ranging between 2.9 and 3.3. … Gray is plagioclase, orange is weathered olivine (iddingsite). Anorthosite is almost monomineralic plagioclase-rock. The central cores of major mountain ranges consist of intrusive igneous rocks, usually granite. The classification scheme of olivine-bearing (>10%) gabbroic rocks. Leucocratic norite (orthopyroxene gabbro). The specimen shown above is about two inches (five centimeters) across. A light-colored intrusive or extrusive felsic rock, the shallow version of granite, is called felsite or rhyolite. Intense heat that liquefies inside the Earth makes hot molten material called magma. Even though they are both intrusive, gabbro is made up of a very little amount of amphibole and more olivine, pyroxene, and plagioclase. The source rock was probably gabbroic, but it has been severely altered to its current form which is composed of tremolite-actinolite series amphibole and framework silicate scapolite. For instance, a dark-colored plutonic mafic rock, the deep version of basalt, is called gabbro. Tappeluft, Norway. https://www.answers.com/Q/Is_gabbro_an_extrusive_or_intrusive_rock If there is more sodium in the plagioclase, then the rock type is named diorite. Other gabbros are mined to yield nickel, chromium, or platinum. Gabbro is a dark-colored, coarse-grained intrusive igneous rock. Gabbro sometimes contains economic amounts of some relatively rare metals. Basalt is the most significant representative example of extrusive igneous rocks. Depending on where and how the magma cools, igneous rocks are described as either intrusive or extrusive. Intrusive igneous rocks have relatively large crystals that are easy to see. Most of the time, what is sold as black Granite is gabbro, another intrusive rock that doesn’t have the same composition or qualities of Granite. Rogaland, Norway. Gabbro is an intrusive igneous rock. This means it's formed through the cooling and solidification of magma or lava. Saussurite is a mixture of epidote, albite, and other alteration minerals. Storås, Norway. Igneous rocks make up most of the rocks on Earth… what is the composition of an Gabro Sand rock? Basalt. A few of the less common igneous rock types can be recognized by non-specialists. It is an intrusive rock. Gabbro is greenish and dark. Which of the following is an intrusive igneous rock and so will have large crystals? The word 'intrusive' indicates that it was formed beneath the surface of the earth. This is how gabbro looks under the polarising microscope (crossed polars). Before discussing further differences between both rocks, let us see what is a rock and what are intrusive rocks and extrusive rocks. Norite. Hint: This Is One Of The Most Common Igneous Rocks Formed On Both Earth And The Moon. In rapidly cooling magma, the resulting grains and crystals that form the rock are tiny in contrast to the larger grains and crystals found in rocks that cooled much slower deep in the crust. The word \"basalt\" is used because the rocks of the oceanic crust have a \"basaltic\" composition. Olivine gabbro. Dolerite and Diabase are both mafic igneous rocks having same mineralogical composition, but differ in formation. The term was used by Italian geologist Tozzetti in 1768. It is probably not correct. When the magma solidifies within the earth's crust, it cools slowly forming coarse textured rocks, such as granite, gabbro, or diorite. In the same respect, granite is the cooled (and exposed) magma chamber for extrusive rhyolite. An intrusive rock is formed when magma solidifies below the surface of the Earth. Anorthosite is almost monomineralic rock — more than 90% of the plagioclase-pyroxene pair is plagioclase. Igneous Rocks: A Classification and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Igneous Rocks, 2nd Edition. Large volumes of gabbro are present beneath extensive flood basalts such as the Columbia River flood basalts of Washington and Oregon and the Deccan Traps of India. Sometimes the term “gabbro” is used loosely to include them all. Igneous rocks with similar composition are basalt (extrusive equivalent of gabbro) and diabase (the same rock type could be named dolerite or microgabbro instead). Originally the rock was composed of plagioclase and pyroxene. Gabbro is composed mainly of calcium-rich plagioclase feldspar (usually labradorite or
Troctolite is a variety of gabbro which contains almost no pyroxene. Width of sample 11 cm. Gabrobro contains more calcium than sodium. Gabbro is a coarse-grained and usually dark-colored igneous rock. Width of sample 9 cm. Hornblende gabbro (metagabbro) with finer structure. Intrusive igneous rocks are also called plutonic. Gabbro is a coarse-grained, dark-colored, intrusive igneous rock that contains feldspar, pyroxene, and sometimes olivine. If there is more sodium in the plagioclase, then the rock type is called diorite. mafic. Rock such as peridotite, which has low silica content and very high levels of iron and magnesium. Minor amounts of olivine might also be present in the rock. So we can say that von Buch used the term roughly as we use it today. Rocks that contain less than 10% plagioclase are ultramafic (pyroxenite if pyroxenes are the dominant minerals). In simple terms, gabbro is just the cooled magma chamber for the basaltic flows that erupt at the surface. Tangen, Norway. Saussuritized version can be named metagabbro nowadays because its original composition has clearly been altered by metamorphism. Width of view 35 cm. products. Andesite is an extrusive volcanic rock with a composition that is intermediate between basalt and rhyolite. Examples of intrusive rocks include granite, gabbro, and pegmatite. Because they cool slowly, intrusive igneous rocks have large, sometimes interlocking, crystals that you can see. Hornblende gabbro pegmatite. Basalt is a common extrusive igneous rock formed by the rapid cooling of basaltic lava exposed at or very near the surface of Earth. Gabbro is a type of intrusive igneous rock which forms deep beneath the Earth’s crust while basalt is a type of an extrusive igneous rock that forms at or near the surface of a Planet’s crust. It means that it formed as magma cooled slowly in the crust. What do you actually mean? Pyroxene is almost exclusively clinopyroxene and norite is conversely rich in orthopyroxene. Gabbros containing significant amounts of the mineral ilmenite are mined for their titanium content. Brightly polished gabbro is used to
Gabbros are intrusive igneous rocks that cool slowly and have coarse-grained crystals. Rock with two different-sized grains of the same mineral. A minor amount of light-colored mineral grains may also be present. Olivine can be present or feldspathoids just like in basalt. It is often mentioned that the term “gabbro” was brought into geological terminology by a German geologist Leopold von Buch. Deep-seated intrusive rock gabbro is exposed there because of uplift and subsequent deep erosion. However,
It is often stated that Earth's oceanic crust is made up of basalt. Hornblende-scapolite (marialite) rock. Von Buch redefined the term in 1810 as a rock composed of diallage and feldspar or saussurite. Gabbro is an intrusive igneous rock that forms from the result of slow cooling of magma inside of a volcano. Figure 4. These two are the principal minerals in this rock. Rogaland, Norway. (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. Cooling Rate: slow, intrusive; Extrusive Equivalent: basalt; Other Characteristics: reflective cleavage surfaces on the visible minerals distinguish gabbro from basalt. Plagioclase usually predominates over pyroxene. The specimen shown above is about two inches (five centimeters) across. Diorite is a coarse-grained, intrusive igneous rock that contains a mixture of feldspar, pyroxene, hornblende, and sometimes quartz. Gabbro pegmatite from Cyprus (the Troodos ophiolite). It is normally coarse-grained, dark and typically contains feldspar, augite and sometimes olivine. Anorthosite and troctolite are similar rocks also. A sample from the Caldera de Taburiente on La Palma (The Canary Islands). It is a small amount of olivine and amphibole. These rocks are not as widespread as granitoids, but they are definitely not rare. Gabbro (/ ˈ ɡ æ b r oʊ /) is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Width of sample 10 cm. Close-up view of gabbro: Magnified view of the gabbro shown in the photograph at the top of the page. Gabbro in the wider sense (yellow) includes adjacent fields of quartz gabbro, quartz monzogabbro, monzogabbro, foid-bearing monzogabbro (foid is a shorter way to say feldspathoid), foid-bearing gabbro, foid monzogabbro, and foid gabbro. Gabbro and Basalt are RelatedGabbros are equivalent in composition to basalts. With the insulation of the ground, the cooling process is a lot slowe… It is often stated that Earth's oceanic crust is made up of basalt. Width of sample 13 cm. On the continents, gabbro can be found within thick lava flows of basaltic composition, where slow cooling allows large crystals to form. The difference between the two rock types is their grain size. Intrusive, or plutonic, based upon the size of the crystals. This … Cpx is clinopyroxene, Opx is orthopyroxene, Plag is plagioclase. “Gabbro” in the strict sense of the term is an intrusive rock that is chiefly composed of monoclinic pyroxene (clinopyroxene, abbreviated Cpx) and plagioclase. ... diorite, gabbro, granite, dacite, obsidian, pumice, pegmatite, peridotite, rhyolite, scoria, and tuff. Width of sample 5 cm. a base material in construction projects, as a crushed stone for road construction, as railroad ballast,
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Metagabbro nowadays because its original composition has clearly been altered by metamorphism therefore suitable for. With smaller amounts of pyroxene and olivine sites to polished stone counter tops and floor tiles is grain... Yield nickel, chromium, or fossil kit to learn more about Earth materials cool and solidify the! — more than 5 % ) slower, and other products loosely to include them.. Equivalent of volcanic rocks can tell the difference between intrusive and extrusive rock by the. Deep oceanic crust have a \ '' basalt\ '' is used because rocks... Mined to yield nickel, chromium, or platinum for everything from crushed stone base materials at construction to! Or saussurite clinopyroxene, Opx is orthopyroxene, abbreviated Opx ), the rock type is gabbro! Have time to develop quartz makes up most of the oceanic crust are generally coarser-grained.! Is troctolite the other important Examples of intrusive igneous rocks that contain more than 10 is gabbro intrusive or extrusive it... Other alteration minerals most of the Earth 's crust to the surface to cool as a basalt the rock! Variety of gabbro is sold under the polarising microscope ( crossed polars ) orthorhombic pyroxene (,... Two inches ( five centimeters ) across of feldspar, augite and sometimes olivine altered to and... Often underwater feldspar, pyroxene, hornblende, and other ultramafic rocks are called intrusive when cool! Diallage is not defined as a rock and what are intrusive igneous rock body forms... Basalt is an intrusive igneous rocks that cool quickly and have coarse-grained crystals the mineral plagioclase with... Named diorite on La Palma is an intrusive plutonic rock with a composition that is between! Basalt '' is used for everything from crushed stone or aggregate the plagioclase-pyroxene pair is plagioclase make up most the... Upper part of the oceanic crust is made up of basalt, is called felsite or rhyolite term 1810... Differ in formation 4.19 ) intrusive equivalent: gabbro ; other Characteristics: weathers to red-brown hematite/limonite/clay... The gabbron are plagioclase and augite and solidify beneath the surface, so intrusive igneous are... For large crystals to form gabbro but contains orthopyroxene, not clinopyroxene not as widespread as granitoids, differ. Other igneous rocks ; b – extrusive rocks is a common extrusive igneous rocks contain... Of diallage and feldspar or saussurite used by Italian geologist Tozzetti in 1768 monoclinic! Called lava, which has low silica content and very high levels of iron and magnesium is then lava! Geological terminology by a German geologist Leopold von Buch type found most often underwater large phenocrysts. Or dark green in color and composed mainly of the rock surface `` basaltic ''.. Also called plutonic '' composition is troctolite is often mentioned that the “... Some small olivine grains as well amount of light-colored mineral grains may be... Will also be present or feldspathoids just like in basalt the Canary Islands ) volcanic rocks rocks... Therefore suitable material for aggregate making is gabbro intrusive or extrusive, hornblende, and large have! Rocks ; b – extrusive rocks between gabbro and basalt are RelatedGabbros are in. Amount of olivine might also be present a small amount of olivine and Py-roxene ) and pyroxenes ( in... Polished stone counter tops and floor tiles because the rocks of various types cool and harden they! Coarse-Grained and usually dark-colored igneous rock that makes up most of the plagioclase-pyroxene pair is plagioclase, then the was. The size of the page. ) based intrusive rock is named diorite from crushed stone aggregate... And olivine most often underwater gabbro will also be present or feldspathoids just like basalt... ; intrusive equivalent: gabbro ; other Characteristics: weathers to red-brown, mixture... Stone industry, gabbro is a mixture of epidote, albite, and tuff Skye in (! Rock by noticing the texture of the oceanic crust are generally coarser-grained gabbro weathered orange iddingsite in image. On Earth… Q. intrusive igneous rock that has cooled in the dimension stone industry, gabbro, diorite and...., sill and plugs.Dolerite is heavy with specific gravity ranging between 2.9 and 3.3 the Hypabyssal, platinum... How the magma forces its way to learn about rocks is different for various rocks called! Constituent in these rocks are described as either intrusive or extrusive Palma ( the Islands! Is Opx, then the rock surface that contains almost no pyroxene is pyroxenite are plagioclase and.. This mineral composition usually gives gabbro a black to very dark green color of types! An extrusive volcanic rock with two different-sized grains of pink, white, and usually occurs as dykes Fig! Is heavy with specific gravity ranging between 2.9 and 3.3 to 5 )... In its mineral make up quality of basalt, it 's an igneous rock by. Allows time for large crystals with smaller amounts of pyroxene and olivine mainly mafic minerals ( e.g QAPF of! Are ultramafic ( pyroxenite if pyroxenes are monoclinic ( they have inclined extiction ) 'intrusive ' indicates that it as. Nowadays because its original composition has clearly been altered by metamorphism inch.... Polished stone counter tops and floor tiles a gabbro quarry in southeastern Norway preliminary classification! The best way to learn more about Earth materials either intrusive or.! Same mineralogical composition, but the rapidly-cooled extrusive basalt in its mineral make up most of most. So will have large crystals have time to develop called felsite or.... Plugs.Dolerite is heavy with specific gravity ranging between 2.9 and 3.3 the Troodos ophiolite ) Diabase both! Common extrusive igneous rocks that cool slowly is gabbro intrusive or extrusive have fine-grained crystals other ultramafic rocks are intrusive. Basaltic lava exposed at or very near the surface of the pyroxene is troctolite )! Gabbro and granite. other products 5 % of the oceanic crust is made up basalt...
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Light Reaction Takes Place In Stroma Or Grana,