Feldspar and quartz are the most common minerals found in rocks. A wide variety of igneous rocks occur in the continental lithosphere, a reflection of its heterogeneous nature compared to oceanic lithosphere. Molten rock that reaches the surface is called lava. Intrusive igneous activity, the cooling of magma within. Igneous rocks form from cooled and solidified magma or lava.
Describe the process of igneous evolution and the role of. Igneous rocks and processes revised on 102011 page 5 of 10 finegrained or aphanitic. A common example of an extrusive igneous rock is basalt. Determination of intrusive and extrusive igneous rocks.
Rocks are an aggregate of one or more minerals held together by chemical bonds. These notes will also be useful for other competitive exams like banking po, ssc, state civil services exams and so on. The book thus serves, uniquely, both as a conventional course text and as a practical laboratory manual. This reader emphasizes how all igneous rocks are formed and explores how the formation is related to igneous rock classification. Igneous rocks introduction textures composition be sure to. Magma is a mixture of liquid rock, crystals, and gas. Textures and structures of igneous rocks pdf file general classification of igneous rocks pdf file.
When igneous or sedimentary rocks come under great heat or. This can occur below the surface of the earth forming intrusive rocks also called plutonic rocks or on or above the surface as extrusive rocks also called volcanic rocks. The classification and nomenclature of igneous rocks are treated in the final section. They are known as intrusive or plutonic igneous rocks. Based on the mode of formation three major groups of rocks are defined. As a generalization, extrusive igneous rocks cool rapidly when compared with intrusive. Also you may use the words in the word bank one time. Lecture notes 3 igneous rocks glendale community college. Hydrothermal activity spatially associated with ultramafic rocks, usually serpentinites, has been observed at several localities proximal.
Igneous rocks formed of cooled lava or volcanic ejecta are common, but most molten material cools below. When lava cools quickly at or near earths surface, we get extrusive volcanic igneous rocks with small or no crystals. See appendix c for links to photos and notes on diagram construction. Identify how igneous rock color relates to chemical. Is a critical step in the development of a crystal. Sedimentary and metamorphic rocks notes can be accessed on notes section of website 6. This and further information about the browser plugins can be obtained by clicking on the icon below.
There are three categories of rocks igneous metamorphic sedimentary the differences between them have to do with how they are formed. Ncert notes on important topics for the upsc civil services exam. Some notes on igneous rock revised april 17, 2020, by vince cronin principle of uniformitarianism. Igneous rocks are formed when magma cools, either on earths surface or beneath it, though some may form by fragmentation of solidifying magma. These uraniferous igneous rocks are to be sought among the acidic and alkalic igneous rocks of ancient shields and massifs or. Introduction to igneous rocks an igneous rock is any crystalline or glassy rock that forms from cooling of a magma.
Rock cycle notes three types of rocks sedimentary igneous metamorphic sedimentary rocks sediment is produced through the process of weathering. An igneous rock is classified on the basis of its mineral. An igneous rock or a part of an igneous rock with a finegrained or aphanitic texture has crystals, but they are too small to recognized with the unaided eye. Very tiny initial crystals have a high ratio of surface area to volume, and thus, a large proportion of ions at the surface however, surface ions have unbalanced charges because lack the complete surrounding lattice. This book is for geoscience students taking introductory or intermediatelevel courses in igneous petrology, to help develop key skills and confidence in identifying igneous minerals, interpreting and allocating appropriate names to unknown rocks presented to them. Plutonic bodies can be tabular, cylindrical or somewhere between equidimensional and irregular. Igneous rocks form from cooling and crystallization of molten rock magma. The physical and chemical laws that govern the physicalchemical world are the same now as in the past. Lecture 4 notes pdf slides are not available for this lecture. Rocks are classified into three distinct groups igneous, sedimentary, and metamorphic and each is discussed in a separate section.
Large rocks are broken down very gradually and the smaller pieces are transported by wind, water, and ice. Sediments produced by weathering and erosion form sedimentary rocks through the process of lithification. Formed when sediments old rocks, dead plant and animal remains are compacted together e. The rocks resulting from volcanic eruptions cool rapidly and are known as extrusive igneous rocks, because the magma was extruded from the earth. Each rock group is further subdivided into subgroups that are defined by the mode of origin of the rocks. Texture refers to the size and arrangement of crystals, glass and pyroclasic material in a rock. An introduction to igneous and metamorphic petrology. This article talks about the different kinds of rocks. Understanding igneous rocks and the minerals of which they are comprised are fundamental knowledge taught within the k12 science curriculum. Lava is molten rock flowing out of fissures or vents at volcanic centers when cooled they form rocks such as basalt, rhyolite, or obsidian. Lecture 5 notes pdf slides are not available for this lecture. Extrusive, or volcanic, igneous rock is produced when magma exits and cools above or. Name date 1 igneous rocks middle school science blog.
Occurrence, texture, and classification of igneous rocks. Teacher notes if your students have completed the plate tectonic units on volcanoes, they should be familiar with different volcanic environments. The term magma refers to molten rock, together with any suspended mineral grains and dissolved gases. Using your knowledge of igneous rocks and esrt page 6, fill in the blanks for letters a through i. Earth, forms one of the most common igneous rocks, granite. Letters a through i indicate parts of the flowchart that have not been labeled.
Igneous rocks are rocks that have solidified from a molten source, called magma. Under high temperature and pressure, the sediment becomes compacted. Engineering geology pdf notes eg pdf notes smartzworld. These rocks are finegrained since minerals crystallize too rapidly to form large crystals. If you choose to download the pdf format lecture notes you will still need the free adobe acrobat reader to view and print the files.
Igneous rock, any of various crystalline or glassy rocks formed by the cooling and solidification of molten earth material. List the examples of igneous, sedimentary, and metamorphic listed in this presentation. Extra credit 001 abreu 003 agena 004 albert 006 araki 091 atiburcio 008 buck 010 byce 011 clements 012 colle 067 peahu 068 santiago 069 shigemitsu 070 soares 084 teramura 086 tomaszek 073 wu 074 yamamoto 075 yanagi 077 yokota 079 zoller. Draw the rock cycle combine the images and notes from figure 4. When magma cools slowly inside earth, we get intrusive plutonic igneous rocks with large crystals. Igneous rocks form from the cooling and crystallization of molten rock material. Lecture notes and slides introduction to geology earth. The engineering geology notes pdf eg notes pdf book starts with the topics covering importance of geology from civil engineering point of view, definition of mineral, importance of study of minerals, geological classification of rocks into igneous, indian stratigraphy and geological time scale, importance of geophysical studies principles. Write the names of three igneous rocks in the provided spaces. Because the continents are not subducted and are subject to uplift and erosion, older plutonic rocks are both preserved and accessible to study. Pdf an introduction to igneous and metamorphic petrology. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
In the modern oceans, the mafic association is found in two specific settings. Igneous petrology igneous rocks are assemblages of minerals predominantly rockforming minerals. When molten rock erupts at the earths surface and flows from a volcano, it is called lava. Igneous rock think about how can two rocks made of the same minerals look very different. Igneous rocks igneous rocks form by cooling and crystallization of molten rock molten material residing below earths surface is known as magma, whereas the same material at the surface is called lava. A magma consists mostly of liquid rock matter, but may contain crystals of various minerals, and may contain a gas phase that may be dissolved in the liquid or may be present as a separate gas phase. Classify igneous rocks according to the proportions of minerals within them. Igneous rocks are defined as types of rocks that are formed when molten rock rock liquefied by intense heat and pressure cools to a solid state.
Typical occurrences of igneous rock bodies on the surface include lava flows, lava domes, necks and spines. Physical geology in our overview of the earth, we found out that earths internal heat combined with other mechanisms causes rocks to melt in the asthenosphere and lithosphere. Rocks are naturally occurring aggregates of mineral grains. Igneous rocks form when magma, molten rock, rises upward. Describes the features of intrusive and extrusive igneous rocks that cool slowly and rapidly, respectively. Petrography the branch of geology dealing with the description and systematic classification of rocks, especially by microscopic examination of thin sections. Igneous igneous rock forms from magma that has cooled and hardened. In practice, this means that the average dimension of the crystals is less than 1 millimeter. Intrusive or plutonic igneous rocks wherein the magma crystallizes at depth in the earth.
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