Introduction As we learned last time, melting of the mantle usually produced basaltic magmas, compositions that are referred to as mafic because of their high proportions of Mg and Fe. Magma, and the igneous rock it becomes, has a range of chemical compositions. Examples of intrusive igneous rocks are granite, diorite, gabbro, and peridotite. The name is appropriate because these rocks are born of fire. Igneous amphibole is made of hornblende, which is composed of an iron-magnesium silicate, a calcium-iron-magnesium silicate and an aluminum-iron-magnesium silicate. Representative Image: Igneous intrusion. Igneous rocks are those that form via the process of melting and cooling. Igneous Rocks . Felsic rocks are rich in silica, potassium, sodium, and aluminum and contain only small amounts of iron, magnesium, and calcium. Mafic igneous rocks. For example, basalt is a mafic lava flow rock which originates from melting of the upper mantle. In geology, mafic is a term which describes an igneous rock or a silicate mineral rich in iron and magnesium. Igneous rocks are basically used in . Igneous rocks get their name from the latin word for fire “igneus”. Felsic rocks are made of light-colored, low-density minerals such as quartz and feldspar. Back. Granite: Granite and other rocks of the granite family are the most widely distributed of the deeper plutonic igneous rocks forming the major component of the earth’s crust. The way that magma turns into a solid rock gives it a distinctive igneous texture. Mafic - igneous rock that is less than 52% silica and rich in Fe, Mg, and Ca. Mineral cleavage and hardness are additional features to help discern between minerals. The term mafic is a combination of the words “magnesium” and “ferric.” The majority of mafic minerals are dark green or greenish black and are medium to coarse-grained. Differences Of Mafic And FelsicYouTube. This lesson will examine the definition of this term and how to relates to earth processes. The mineral compositions of igneous rocks are usually described as being felsic, intermediate, mafic, or ultramafic (as examples, see Figure 4.7 and Figure 4.8). Now that we have learned that granite, rhyolite, and other common types of rock are igneous, we can think about all the times we see igneous rocks in day-to-day life.Now you can categorize any granite statue you see around as extrusive or intrusive (remember – can you visually see the crystals of pure composition inside?) Mafic rock is an example of igneous rock which is dominated by olivine, silicates pyroxene, mica, and amphibole. Since igneous rocks are characterised by silica content in them, mafic is the one with less silica content (approx. Basalt and gabbro are the extrusive and intrusive names for mafic igneous rocks, and peridotite is ultramafic, with komatiite as the fine-grained extrusive equivalent. The quick cooling gives this rock a glassy look. Definitions Gabbro is an example of a mafic rock. Intrusive igneous rock - forms under the earth’s surface . Rocks composed mostly of hornblende and intermediate plagioclase feldspars make up the intermediate family of igneous rocks. Typical felsic rocks are dacite and rhyolite. ; Mafic rocks are dominated by plagioclase and pyroxene (even if you can't see them with the naked eye) and smaller amounts of olivine. You may have noticed that there are many kinds of rocks, from the soft sandy rocks that form the cliffs at Scripps beach to the hard rocks … Course grained example of intermediate igneous rock. Tend to be light-colored and less dense. INTRODUCTORY GEOLOGY IGNEOUS ROCKS 8.8 STUDENT RESPONSES 1. The Many Uses of Igneous Rock. A common mafic rock is basalt. Common mafic rock samples are basalt and gabbro. Figure 2 schematically illustrates the occurrence of igneous (mafic and felsic) rocks in the LHS, with lithological characteristics of the Kali Gandaki Supergroup and inferred depositional environment (modified from Sakai, Iwano, Danhara, Takigami, et al., 2013) with some age information. The four classifications of igneous rocks are ultramafic, mafic, intermediate, and felsic. Intermediate magmas are somewhat more viscous than the mafic magmas. Click any image to enlarge. 0-15%MCI 2. b. Obsidian with iron. The felsic plutonic rocks usually have quartz, large proportions of potassium feldspar (orthoclase), and lesser amounts of plagioclase and mafic minerals. Plutonic rocks are igneous rocks that solidified from a melt at great depth. The dominant mineral of the rock is alkali feldspar which occurs as large crystals. Rhyolite. Mafic is a term used by geologists to describe igneous rocks and minerals. Examples of Igneous Rocks Examples of metal depleted mafic rocks associated with economic or subeconomic concentrations of Ni-Cu-PGE sulfide mineralization are recognized in several other large igneous provinces: 1. A great example of a glass igneous rock is obsidian, which cools quickly on the surface of the earth after erupting from a volcano. The difference in elemental composition causes mafic rocks to be denser than felsic rocks. First Mafic rocks are darker and denser than Felsic rocks. Therefore, rocks are divided into ultramafic, mafic, intermediate, and felsic. • Magmatic segregation deposits: –formed in intrusive bodies –ore deposits formed during fractional crystallisation • Exceptions: Igneous rocks are derived from the Latin word Ignis which means of fire or heat, the name best describes these rocks since they are born of fire. Basalt. All of these minerals contain iron and magnesium. ES10 - EARTH Lecture 6 - Igneous Rocks Lisa Tauxe Rocks - a brief overview The solid Earth (the mantle and crust) is made of rock. The classification is done based on their silica content, as silica is usually the most abundant of all the oxides present. If the rock is highly dominated by Magnesium and Iron, it is called Ultramafic. Diorite. The following is an example of igneous rocks. Plutons include batholiths, stocks, dikes, sills, laccoliths, lopoliths, and other igneous formations. It is a light coloured rock. a. Igneous Rock # 1. Get Price; Igneous Rock Granite. Igneous rocks are classified on the basis of their composition and their texture. In geology, a pluton is a body of intrusive igneous rock (called a plutonic rock) that is crystallized from magma slowly cooling below the surface of the Earth. There are a couple things that differ Mafic rocks from Felsic. What color are mafic igneous rocks and how much feMg. Igneous rock is one of the three main types of rocks; other ones are sedimentary rocks and metamorphic rocks.Igneous rock is formed from the cooling and solidification of molten magma. Ore deposits related to mafic igneous rocks • Range from largest, most extensive igneous petrologic systems in the world (e.g., Bushveld Complex) down to moderate-sized bodies like carbonatites. Difference Between Mafic and Felsic Rocks. What is Igneous Rock. igneous rock uses are specific to its . Also Mafic rocks are rich in calcium, iron, and magnesium, and poor in silicon. Sample 11 has what mafic color index (MCI)? As per Wikipedia, “Igneous rock (derived from the Latin word ignis meaning fire) is one of the three main rock types, the others being sedimentary and metamorphic.Igneous rock is formed through the cooling and solidification of magma or lava. See Some Examples. Learn geology igneous rocks with free interactive flashcards. Igneous Rocks.pdf from GOVT 1403 at Lone Star College System. 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