Intrusive rock is igneous rock, that is formed by the crystallized magma deep within the earth. Various colors exist amongst the ultramafic rocks such as peridotite, which is a dark green. Describe the environments where basalt accumulates learning objectives lo 1. Theres just a bewildering number of rocks to remember, minerals to be familiar with and textures to recognise. Potassic ultramafic igneous rock forming small volcanic pipes, dykes and sills volatilerich dominated by olivine with subordinate minerals of mantle derivation. Many mountain ranges, such as the sierra nevada in california, are formed mostly from large granite or related rock intrusions. Igneous rocks form through the solidification of molten or partially molten rock lava on the surface or magma underground. This will lead us into discussions on magma, silicate minerals, and the construction of a useful illustration that may be used to both name an igneous rock and determine its mineral content. Conclusion of the rock cycle igneous can change to metamorphic, metamorphic to sedimentary,sedimentary to igneous or igneous to sedimentary. Since a rock is a mixture of minerals our discussion of the igneous rocks peridotite, gabbro, basalt, diorite, andesite, gran ite, and rhyolite figure 2 means we. Igneous rocks are categorized by light, medium and dark colors. Igneous rock is formed through the cooling and solidification of magma or lava. Sedimentary rocks that cooled at the surface volcanic and interior to the surface plutonic of the earth, respectively.
Igneous rock formation intrusive igneous rock volcanic and lava rocks igneous rocks are called fire rocks formed either underground or above ground. Parent material of igneous rocks forms from partial melting of rocks magma at surface is called lava general characteristics of magma general characteristics of magma. Igneous rock igneous rock classification of plutonic rocks. This can happen beneath or above the surface, resulting in 2 subtypes. In addition, igneous rocks make up large parts of all the continents and nearly all of the oceanic crust, which is formed continuously by igneous activity at divergent plate boundaries.
Click the circle by an answer with the mouse, then click on the submit button to get a response. This reader emphasizes how all igneous rocks are formed and explores how the formation is related to igneous rock classification. This term applies to igneous rocks in which certain mineral grains called phenocrysts greatly exceed the average grain size of the rock fig. Rock identification adapted from don peck page 5 of 16 the rock identification key about the rock identification key this rock key has been designed and written to assist children and adults in identifying the common rocks they find in their back yards and on memorable vacations. They often haves large crystals interlocked together to form the rock mass. The most general nongenetic term for layering in metamorphic rocks is foliation. An extrusive igneous rocks definition states these rocks form when magma exits and cools above or very near the earths surface. Their attributes and geologic settings national park service. Igneous rock classification of plutonic rocks britannica. Igneous rocks comprise such types as the common granites which formed from tremendously large masses of molten material intruded from depths of the earth into the crust, then 1. Ideas about the evolution of igneous rocks go back to the early part of this century, and n. The evolution of the igneous rocks work by bowen britannica.
Pdf classification of intrusive igneous rocks using. Identify the information revealed by igneous texture 4. Any use of trade, firm, or product names is for descriptive purposes. An igneous rock is composed of felsic silicate minerals like quartz, mica, and feldspar. Igneous rocks and volcanoes practice exam questions written by timothy h. Intrusive igneous activity, the cooling of magma within. Density and magnetic susceptibility values for rocks in the talkeetna mountains and djacent region, southcentral alaska y elizabeth a. Intrusions are one of the two ways igneous rock can form. Ore deposits of mafic igneous rocks geology papers. Extrusive igneous rocks finegrained or glassy lava flows volcanoes intrusive igneous rocks medium to coarsegrained hypabyssal transitional between fine and coarsegrained. They are formed when magma molten rock, typically derived from the earths mantle solidifies. Examples include basalt, rhyolite, andesite, and obsidian. Igneous textures the texture of a rock is a result of various processes that controlled the rock s genesis and, along with mineralogy and chemical composition, provides information that we may use to interpret the rock s origin and history table 3. In the vernal mesa quartz monzonite abundant phenocrysts of microcline feldspar 1 to 2 inches long form about 20 to 30 percent of the rock.
Experimental study of rocks systems, brought together in his evolution of the igneous rocks 1928. Teacher notes if your students have completed the plate tectonic units on volcanoes, they should be familiar with different volcanic environments. Introduction to igneous rocks an igneous rock is any crystalline or glassy rock that forms from cooling of a magma. While there are many different types of rocks, igneous rocks are formed from volcanic. 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. Metamorphic rocks were formed through recrystallization, in anessentially solid. You can skip questions if you would like and come back to them. 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.
Extrusive igneous rocks form when magma reaches the earths surface a volcano and cools quickly. Explain why obsidian is a felsic igneous rock, even though it has a dark color. Igneous rock textures texture refers to the size, shape and arrangement of grains texture of igneous rocks is controlled by cooling rate extrusive rocks cool quickly at the earths surface and are finegrained small rocks cool slowly deep beneath. Other articles where the evolution of the igneous rocks is discussed. The rock was termed eruptive granite upon the hayden map. This worksheet has 14 earth science regents questions about igneous rocks.
Theyre all connected to the endless rock cycle, moving from one type to a different and dynamic form, texture and even chemical composition of the method. Igneous petrology cheat sheet 1 practical igneous petrology for dummies we can all be dummies when it comes to looking at igneous rocks. In practice, this means that the average dimension of the crystals is less than 1 millimeter. The cooling of thick igneous bodies on a young earth 15 24 wt%. Extrusive igneous rocks, or volcanics, form when magma makes its way to earths surface. Each classification is useful for a certain purpose and reflect a particular way of looking at igneous rocks. The magma can be derived from partial melts of existing rocks in either a planets mantle or crust. Extrusive igneous rocks erupt onto the surface, where they cool quickly to form small crystals. Sedimentary to metamorphic or metamorphic to igneous. Plutonic bodies can be tabular, cylindrical or somewhere between equidimensional and irregular. Density and magnetic susceptibility values for rocks in.
The molten rock erupts or flows above the surface as lava, and then cools forming rock. Igneous rocks formed at some depth plutonic rocks will be coarsegrained. Choose your answers to the questions and click next to see the next set of questions. Experimental petrology, both at the lowtemperature range explored by van t hoff and in the high ranges of temperature investigated by bowen, continues to provide laboratory evidence for interpreting the chemical history of sedimentary and igneous rocks. Therefore, with an understanding of how different kinds of rocks were formed, it is. Bowen did extensive experimentation with igneous minerals and rocks and developed many of the principles of phase diagrams and their interpretation which are integral to understanding igneous rock evolution. The classification and nomenclature of igneous rocks are treated in the final section. Pdf types and physical properties of igneous rocks of popov. There are 3 nice classes of rocks, igneous, sedimentary and metamorphic, and most of the time, they are easy to inform apart. Plutonic rocks igneous rocks that solidify below the surface of the earth. Cooling of thick igneous bodies answers in genesis. Occurrence, texture, and classification of igneous rocks. Describe the process of igneous evolution and the role of 7. These rocks include andesite, basalt, dacite, obsidian, pumice, rhyolite, scoria, and tuff.
Typically, the melting is caused by one or more of. Magma and igneous rock magma forms from the partial melting of rock in the subsurface. It does so in a few different ways, including filling and widening existing cracks, melting the surrounding rock called country rock 1, pushing the rock aside where it. Experimental petrology, both at the lowtemperature range explored by van t hoff and in the high ranges of temperature investigated by bowen, continues to provide laboratory evidence for interpreting the. Magmas and igneous rocks magma and igneous rocks igneous rocks are formed by crystallization from a liquid, or magma. Examples of extrusive igneous rocks include basalt, andesite, rhyolite, dacite, obsidian, pumice and scoria. The mass of mount marcellina bears irregular relationship to the sedimentary rocks. Composed of mainly silicon and oxygen, so when it cools it crystalizes to an igneous rock composed of silicate minerals magma at the surface is called lava. One important reason to study igneous rocks and intrusive igneous activity is that igneous rocks are one of the three main families of rocks. The sio 2 may occur as free quartz or be combined with varying proportions of elements to form minerals such as feldspar. Typical occurrences of igneous rock bodies on the surface include lava flows, lava domes, necks and spines, and pyroclastic deposits. The cooling process may be fast or slow, and determines the color and texture of the intrusive rock.
Types and physical properties of igneous rocks of popov island in peter the great bay of the sea of japan article pdf available in russian journal of pacific geology 82. Igneous rocks are formed when magma cools, either on earths surface or beneath it, though some may form by fragmentation of solidifying magma. Read igneous rocks to find the answers to these questions and many more. Pdf types and physical properties of igneous rocks of. Silica content in most magma ranges from 45 to almost 80 percent by weight see figure 4.
Igneous rocks with a finegrained texture grains generally tiny or too small to see are volcanic in origin. Pdf classification of intrusive igneous rocks using digital. Magma is rich in silica, present as sio2, except in rare cases. Igneous rock derived from the latin word ignis meaning fire, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Some cool so quickly that they form an amorphous glass. These colors correspond to felstic, intermediate and mafic, which indicate the amount of mafic materials chiefly magnesium and iron in an igneous rock.
A usually light colored high in silica igneous rock that is found in continental crust, is the most abundant intrusive rock, and forms the core of many mountain ranges intrusive rock cools deep below the surface forming very large crystals. Underground, they are formed when the melted rock magma deep within the earth becomes trapped in small pockets. Earth, forms one of the most common igneous rocks, granite. Igneous rock or magmatic rock, is one of the three main rock types, the others being. Rocks formed from lava are extrusive, or volcanic rocks. Ore deposits of mafic igneous rocks pges diamonds carbonatitehosted copper ore deposits of intermediate to felsic igneous rocks. Petrography the branch of geology dealing with the description and systematic classification of rocks, especially by microscopic examination of thin sections. Plutonic rocks are always intruded into preexisting sedimentary. Igneous rocks are one of the three main rock types igneous, sedimentary, metamorphic.
They include two types zvolcanic or extrusive igneous rocks form when the magma cools and crystallizes on the surface of the earth zintrusive or plutonic igneous rocks wherein the magma crystallizes at depth in the earth. Igneous rocks are classified is several ways, and methods of classification have evolved a lot over the past 100 years. Choose the best possible answer to the following questions for all of chapter 4. Igneous rocks intrusive igneous rock magma free 30. Questions relate to using the earth science reference tables page 6 scheme for igneous rocks, environment of formation extrusive vs. These rocks are also referred to as intrusive rocks. The table below shows classification of major groups of igneous rocks based on their mineral composition and texture. The lava comes from the upper mantle layer, between 50 km and 150 km below the earths surface when lava erupts onto the earths surface, it cools quickly. Rocks are the physical record of past events in earths history. Igneous rocks form as molten rock cools and solidifies general characteristics of magma. In any classification scheme, boundaries between classes are set arbitrarily. 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.
Igneous rocks and processes revised on 102011 page 5 of 10 finegrained or aphanitic. Intrusive igneous rocks make up the majority of igneous rocks and are formed from magma that cools and solidifies within the crust of a planet known as plutons, surrounded by preexisting rock called country rock. Concepts and testing article pdf available in geotechnical and geological engineering 322. All rock classifications are based on two criteria, however, mineral content of the rock, and texture grain size. The names of common igneous rocks based o n the minerals and texture. All these rocks can even change straight back to their original form. Heaton, professor of earth sciences, university of south dakota. Intrusive rock forms within earths crust from the crystallization of magma. Some examples of sedimentary rocks are limestone, shale, conglomerate, clays, quartz and dolomite are the common dominant mineralsinthem. The three minerals at the bottom do not form by reaction with the firstformed crystals. There are both multiple choice and fillin questions. Welcome to the companion site for igneous rocks and processes. Igneous rock is formed from volcanic molten rock either while underground, intrusive, or from the exterior of a volcano, extrusive.
Sedimentary rocks do not weather as rapidly as the igneous rocks. Rocks formed from magma at depth are intrusive, or plutonic rocks. They are known as intrusive or plutonic igneous rocks. Glen1 penfile report 03268 003 logical survey editorial standards or with the north american stratigraphic code.
This intrusive cooling process occurs very slowly in comparison to extrusive rock. Igneous rocks originated through solidification of molten material either at or below the surface. Plagioclase makes up the continuous reaction series. Extrusive rocks are formed from magma above the surface, while intrusive igneous rocks form from magma beneath the surface. Igneous rocks that cooled at the surface volcanic and interior to the surface plutonic of the earth, respectively. Eastern united states white mountain plutonic series in. The lava comes from the upper mantle layer, between 50 km and 150 km below the earths surface. A plutonic rock may be classified mineralogically based on the actual proportion of the various minerals of which it is composed called the mode. Youll also find a handson activity to try at home or at school, as well as a glossary of unfamiliar words, resources to help you locate additional information, and a useful index. Igneous rocks and processes revised on 102011 page 3 of 10 reaction series contains all of the common ironforming ferromagnesian minerals. Such rocks are characterised by the presence of distinct sediments or layers in them.
In conclusion all rocks can form into anyother type of rock. Igneous rock forms as magma cools and minerals crystallize from the magma. Plutonic rocks, ranging from gabbro to granite in alkalic provinces of the. Typical occurrences of igneous rock bodies on the surface include lava flows, lava domes, necks and spines. Igneous rocks pictures of intrusive and extrusive rock types. Igneous petrology cheat sheet 1 imperial college london. Extrusive igneous rocks are types of igneous rocks that form when hot magma from inside the earth extrudes to the surface as lava which hardens and cools immediately to form small crystals.
A rock is a naturally formed, consolidated material usually composed of grains of one or more minerals the rock cycle shows how one type of rocky material gets transformed into another representation of how rocks are formed, broken down, and processed in response to changing conditions processes may involve interactions of geosphere with hydrosphere, atmosphere andor biosphere. Extrusive igneous rocks form when lava hardens and cools. To simplify the discussion we are severely reducing the number of. This cheat sheet pack contains some practical advice on. Chapter 4 magmas, igneous rocks, and intrusive activity. Komatiite is a very rare and old extrusive igneous rock. To simplify the discussion we are severely reducing the number of igneous rocks you need to know to an essential few. Plutonic bodies with different dimensions and geometry form. Pictures and brief descriptions of some common igneous rock types are shown on this page. Igneous rocks with a porphyritic texture large grains phenocrysts surrounded by a finergrained groundmass cooled in a twostage process, first slowly and then more rapidly. Identify how igneous rock color relates to chemical 5.
89 975 1368 18 895 854 509 1447 710 1148 1271 1165 723 1064 743 1293 718 963 495 1141 932 1324 355 1292 105 732 623 557 1535 362 288 839 656 610 70 969 1208 475 681 993 380