Ndsu geosciences petrology 422622 petrology, petrography. Petrologists also include the principles of geochemistry and geophysics through the study of geochemical trends and cycles and the use of thermodynamic data and experiments in order to better understand the origins of rocks. The rock names for volcanicextrusive and plutonicintrusive rocks are written above. General classification of igneous rocks tulane university. For instance the mynydd mawr intrusion in snowdonia nockold, 1938 has a peralkaline composition, which is characterized by a high content of na and k and relatively low al. Characteristic of potassic hydrothermal alteration. Catharines, ontario, has a complete set of lecture notes for a. Classification and nomenclature of igneous rocks prof. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as. These uraniferous igneous rocks are to be sought among the acidic and alkalic igneous rocks of ancient shields and massifs or. This was necessary because the first day of class was cancelled.
The use of visualization and sketches of thin sections to encourage a better understanding of phase diagrams. Introduction to mineralogy and petrology sciencedirect. Those minerals listed in capital letters are most likely to be encountered. The study of igneous, sedimentary and metamorphic rocks by loren a. A links page for mineralogy and petrology resources, by john winter. Because igneous rocks form under diverse conditions, they differ widely in texture, mineral composition, and appearance. Igneous rocks pictures of intrusive and extrusive rock types. Conoscopic 1 f 25 jan 5 fundamentals of igneous petrology m 28 jan 6 classification and textures of igneous rocks biaxials. Most of the rocks available for study come from the earths crust, but a few, such as eclogites, derive from the mantle. Coleman, university of wisconsin, oshkosh and university of north carolina. Petrology of igneous and metamorphic rocks gly 4310c. Texture refers to degree of crystallinity, grain size, and geometrical relationships between the cons tituents of a rock fabric.
Igneous petrology igneous rocks are assemblages of minerals predominantly rockforming minerals. Igneous petrology is concerned with the identification, classification, origin, evolution, and processes of formation and crystallization of the igneous rocks. This webpage provides a compilation of online instructional resources and teaching activities related to optical mineralogy and petrography. Igneous rock is formed through the cooling and solidification of magma or lava. Since then these samples and the samples returned by apollo 12 have been subjected to scientific investigations by hundreds of scientists from many. 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. The magma can be derived from partial melts of existing rocks in either a planets mantle or crust.
Course notes on optical mineralogy can be found in both html and pdf formats on the tulane university geology dept. Igneous rocks west virginia geological and economic survey. Minerals of igneous rocks 1 the ferromagnesian minerals contain iron fe and magnesium mg may or may not contain aluminum al. 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. Petrology utilizes the fields of mineralogy, petrography, optical mineralogy, and chemical analysis to describe the composition and texture of rocks. 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. If your web browser has the proper plugin installed, clicking on the pdf will bring the file into your web browser from which you can then print the notes. Naming igneous rocks dexter perkins, university of north dakota. Igneous rocks crystallize from molten magma or lava. Apatite is a minor but ubiquitous mineral in most igneous rocks. Rocks formed from lava are extrusive, or volcanic rocks. Igneous rocks are classified according to mode of occurrence, texture, mineralogy, chemical composition, and the geometry of the igneous body.
Quartz, potassic feldspar, plagioclase, nepheline, muscovite, pyroxenes. In the modern oceans, the mafic association is found in two specific settings. Typically, the melting is caused by one or more of. Examples include basalt, rhyolite, andesite, and obsidian. The classification and nomenclature of igneous rocks are treated in the final section. Involves a c ombination of mineralogical, chemical and field data. Intrinsic parameters such as temperature, oxygen fugacity, and sulfur.
Notice that this is a rough way to determine a rock name. Mineralogy, petrology, and geochemistry of the lunar samples. Minerals in abundances pdf portable document format versions of the lecture notes are optimized for printing. Complex solid solutions within both systems yield divergent magnetic signatures, which are dependent on primary mineralogy, on deuteric cooling, and on postdepositional alteration of the host rock. Hand specimen and thin section description of igneous rocks.
Extrusive igneous rocks form when magma reaches the earths surface a volcano and cools quickly. If possible, determine the modal mineralogy page 17. Albee on july 24, 1969, the first extraterrestrial samples, with the exception of meteorites, were returned to earth by apollo 11. Igneous rocks formation, occurrence and crystallization of magma magma is the parent material of igneous rocks. Metamorphic petrology 1 metamorphic processes, contact, regional, t. September 18, 2017 a revised version of the syllabus is now posted. Albee on july 24, 1969, the first extraterrestrial samples. Occurrence, texture, and classification of igneous rocks. Raymond pdf, epub ebook d0wnl0ad petrologythe study of the nature, composition, origin, and history of rocksis central to understanding earth history. Minerals of igneous rocks 1 the ferromagnesian minerals contain iron fe and magnesium mg may or may not contain aluminum al coin is 2. Minerals in igneous rocks must have high melting points and be able to coexist with, or crystallize from, silicate melts at temperatures above 800. Pdf the mineralogy chemistry tectonic settings and. Mineralogy, petrology, and geochemistry of the lunar samples arden l.
The birefringence is usually 2 nd and 3 rd order and so epidote, with its high relief. All major rocks from each classified groups are discussed and depicted with physical and chemical properties, grain size, texture and structures, and identification by. V, cr, mn, fe, co, ni, and cu in oxide and silicate minerals causes them to be opaque or strongly colored so that the streak, the ma rk that they leave when. Magma can cool on the earths surface, where it has erupted from a volcano extrusive rock or under the earths surface, where it has intruded older rocks intrusive rock. Mineral composition controls such properties as hardness, density, and. Chemical composition of igneous rocks expressed by means of. Other articles where igneous petrology is discussed. Petrologic, petrographic, and petrogenetic studies can.
Igneous rock igneous rock mineralogical components. A branch of petrology dealing with the origin and formation of rocks. Igneous rocks that crystallize slowly beneath the earth s surface, typically have visible individual minerals. Pdf the iugs systematics of igneous rocks researchgate. Lecture notes petrology earth, atmospheric, and planetary. In how far may the systematic classification of igneous rocks, the basis of their petrographic. Uncommon in good crystals, tabular or short prismatic, with pseudohexagonal outline, to 3 m. Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical including optical properties of minerals and mineralized artifacts.
As the magma loses heat, it cools and crystallizes into an igneous rock. The iugs mineralogical based classification and nomenclature scheme for phaneritic and aphanitic igneous rocks. Degree of crystallinity holocrystalline composed wholly of crystals. The natural classification of igneous rocks journal of the. Igneous rocks are formed when magma cools, either on earths surface or beneath it, though some may form by fragmentation of solidifying magma. Binary and ternary phase diagram exercises jennifer m. The aeromagnetic mineralogy of igneous rocks canadian. Igneous and metamorphic petrology are commonly taught together because they both contain heavy use of chemistry, chemical. Petrography the branch of geology dealing with the description and systematic classification of rocks, especially by microscopic examination of thin sections. Although acid igneous rocks generally have simple mineralogies dominated by feldspar and quartz, in some instances more unusual compositions generate a more varied mineralogy.
These silicate minerals include feldspars plagioclase feldspar, potassium feldspar, quartz, micas muscovite, biotite, pyroxenes augite, amphiboles. Igneous rocks can be generally classed according to their silica content with lowsilica 50 % sio 2 igneous rocks being termed basic or mafic, and highsilica igneous rocks being termed. Geo 426p igneous and metamorphic petrology organizational. Extrusive igneous rocks tend to cool much more rapidly, and the minerals grow quicker and can not get as large. We can easily the inadequacy of a mineralogical classification based on minerals present if you look at the classification schemes for volcanic. Even though magma and lava do not denote, nor imply, differences in mineral composition the geographic distinction plays an important role in the physical. Introduction to igneous rocks an igneous rock is any crystalline or glassy rock that forms from cooling of a magma. The major mineralogical components of igneous rocks can be divided into two groups. Very common mineral in metamorphic and igneous rocks. The classification of the many types of different igneous rocks can provide us with important information about the conditions under which they formed. Pdf the mineralogy chemistry tectonic settings and origin. Magnetic minerals in igneous rocks are dominated by phases in the system feofe 2 o 3 tio 2 and the system fenis. The composition of magma is limited to the eight common elements of the earths crust.
The texture and chemical or mineralogical compositions of an igneous rock can give us information on where and how the rock formed. Oct 01, 20 the volcanic igneous rocks are always extremely fine grained and they may be massive or vesicular or amygdaloidal. Hydrothermal activity spatially associated with ultramafic rocks, usually serpentinites, has been observed at several localities proximal. Igneous rocks form as molten rock cools and solidifies general characteristics of magma. Pdf mineralogy of igneous metamorphic rocks imbarak. Igneous rocks form when magma, molten rock, rises upward. Minerals in abundances pdf version of this file and get started right away. Mineralogical composition of igneous rocks with decreasing silica sio 2 content.
Geo 426p igneous and metamorphic petrology organizational matters instructor. Mcdermott the basic terminology of igneous petrology. Identifying light colored minerals students should understand the relationships between rocks and minerals, be familiar with mineral components of basic igneous rocks types, understand why different minerals are found in different igneous rocks, and be able to identify light colored minerals in hand. These elements combine within a melt to form silicate minerals, the most common minerals of igneous rocks. The properties of rocks depend upon their mineral composition texture, and struc ture. Rocks are classified into three distinct groups igneous, sedimentary, and metamorphic and each is discussed in a separate section. The volcanic igneous rocks are always extremely fine grained and they may be massive or vesicular or amygdaloidal. These uraniferous igneous rocks are to be sought among the acidic and alkalic igneous rocks of ancient shields and massifs or within more recent orogenic belts. The felsic minerals include quartz, tridymite, cristobalite, feldspars plagioclase and alkali feldspar, feldspathoids nepheline and leucite, muscovite, and corundum. Diagrams explaining the physical principles behind optical mineralogy are available, as well as photomicrographs illustrating many of the points discussed. For example, if a basaltic magma containing mgrich olivine mixed with a rhyolite magma containing quartz and the magma was erupted before the quartz or olivine could be redissolved or made over into another mineral, then we would produce a rock containing mineral that are out of equilibrium.
Petrology of igneous and metamorphic rocks gly 4310c spring term, 2012. Each rock group is further subdivided into subgroups that are defined by the mode of origin of the rocks. Typical occurrences of igneous rock bodies on the surface include lava flows, lava domes, necks and spines. First determine composition, which is based on mineral content or color, if you cant see minerals.
Conoscopic 2 w 30 jan 7 structures of igneous rocks optical orientation. This might leave disequilibrium mineral assemblages. Pdf in order to create a sustainable classification of igneous rocks which all geologists might use. Petrology and mineralogy of igneous rocks content writer. Igneous rocks are classified according to mode of formation and mineralogy such as plutonic versus volcanic, style and forms, felsic, intermediate, mafic and ultramafic. Mineralogy and petrology welcomes manuscripts from the classical fields of crystallography, mineralogy, petrology, geochemistry, as well as their applications in academic experimentation and research, materials science and engineering, for technology, industry, environment, or society. Anywhere on the earth, the temperature increases proportionally with the depth. Although the modal proportion of apatite in common rocks is generally low, it can reach high concentrations in enclaves, cumulates, and other rocks of low abundance i. The major types of sedimentary rocks distribution of sediments on the earths surface. The journal strongly promotes crossfertilization among earthscientific and applied materialsoriented. Catharines, ontario, has a complete set of lecture notes for a course in optical mineralogy online.
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