Migmatites
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Migmatites are mixed rocks formed near large granite intrusions when magma is injected into neighboring metamorphic rock. They contain a paleosome of unaltered parent rock and a neosome of newly formed rock that may be leucocratic or melanocratic. Migmatites exhibit a variety of structures depending on the degree of melting, including dietzonic, schollen, phlebitic, stromatic, and folded structures. They are associated with high-temperature metamorphic facies and often found in close association with other high-grade metamorphic rocks. Common uses include cement manufacture, road aggregate, and building stone.
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Komattite
Named after the Komati River in South Africa.
first described by Morris and Richard (twins) for ultramafic units in the Barberton Greenstone belt of South Africa.
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distributed in the Archaean shield areas.
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Mostly a volcanic rock; occasionally intrusive.
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Spinifex texture-typical of Komatiites:
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Metamorphic rocks form when rocks are altered by heat, pressure, and chemically active fluids. This process is called metamorphism. There are two main types of metamorphism - contact metamorphism near igneous intrusions which alters rocks locally, and regional metamorphism over large areas from tectonic forces which produces foliated rocks. Metamorphic rocks show different textures based on their grade including slate, phyllite, schist, gneiss, and quartzite, and are important construction materials.
Rocks.pptx
This document summarizes the three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from the cooling and solidification of magma either below the surface (intrusive) or above (extrusive). Sedimentary rocks form through the compaction and cementation of sediments. Metamorphic rocks were once igneous or sedimentary rocks that were changed by heat, pressure, and chemical fluids within the Earth. Examples of each rock type are provided along with brief descriptions of their characteristics and formation processes.
Geotechnics & applied geology 21306006
This document provides an overview of petrology and the classification of rocks. It discusses the three main types of rocks - igneous, metamorphic, and sedimentary rocks. For each rock type, it describes their origin and formation processes. It also discusses various rock properties such as texture, structure, and mineral composition. The document emphasizes the importance of petrology for civil engineering applications when constructing with and building on various rock formations.
Texture of Igneous Rock.pptx
Notes/ppt/information on texture of igneous rock geology .
For more information and source of knowledge:- ·
https://egyankosh.ac.in/bitstream/123456789/66685/1/Unit-2.pdf
1 igneous
Petrology is the branch of geology that studies rocks. It includes the origin and formation of rocks (petrogenesis) and their classification and description (petrography). There are three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form from cooling magma or lava. Sedimentary rocks form from the compaction and cementation of sediments. Metamorphic rocks form from changes to existing igneous and sedimentary rocks via heat, pressure, and chemical reactions.
Rocks
Igneous rocks form as magma cools and solidifies. There are different textures that form depending on the cooling rate, including aphanitic (fine-grained), phaneritic (coarse-grained), porphyritic, glassy, pyroclastic, and pegmatitic. Common igneous rocks include granite, rhyolite, obsidian, pumice, andesite, diorite, basalt, and gabbro. Sedimentary rocks form through the lithification of sediment. There are three main types - clastic sedimentary rocks like sandstone that form from cemented sediments, chemical sedimentary rocks like limestone that form from precipitation, and organic sediment
Metamorphic textures
This document discusses metamorphic textures, which refer to the physical appearance or arrangement of minerals in metamorphic rocks at the microscopic level. There are several types of textures that can form during metamorphism due to factors like heat, pressure, and chemically active fluids. Typomorphic textures are characteristic of metamorphism and include porphyroblastic, mortar, and granoblastic textures. Relict textures are inherited from the original rock, such as ophitic or porphyritic textures. Reaction textures involve chemical reactions between minerals, forming textures like coronas or reaction rims. The document provides examples of different textures and concludes that textures provide information about the metamorphic conditions and original rock type.
E.g ex 3 igneous rocks (2015-16 )
Igneous rocks form from the cooling and solidification of magma or lava. There are three main types based on formation environment: volcanic, hypabyssal, and plutonic. Volcanic rocks form from lava at the Earth's surface and are typically fine-grained. Plutonic rocks form deep underground and are usually coarse-grained due to slow cooling. Texture depends on factors like cooling rate and mineral composition, ranging from glassy to phaneritic. Igneous rocks are classified based on their mineralogy and chemistry, particularly their silica content.
Petrology
This document provides an overview of petrology, the geological classification of rocks, and their structures and textures. It discusses the three main types of rocks - igneous, sedimentary, and metamorphic - and how they form. Igneous rocks form from the cooling of magma or lava. Sedimentary rocks form through the compaction and cementation of sediments. Metamorphic rocks form from changes to existing rocks through heat, pressure, and chemically active fluids. The document also outlines common structures within each rock type, such as vesicles in igneous rocks, stratification in sedimentary rocks, and foliation in metamorphic rocks. Finally, it discusses the importance of petrology for civil
Structures and textures of metamorphic rocks
It is useful for the Under Graduating students for easy understanding and it's useful for the exam preparations.
Petrology
The document provides information about petrology, which is the study of rocks. It discusses the structure of the Earth and defines rocks as aggregates of minerals. Rocks are classified based on their geological origin as igneous, sedimentary or metamorphic. Igneous rocks form from the solidification of magma or lava and include intrusive and extrusive types. Sedimentary rocks form from the compaction or cementation of sediments derived from pre-existing rocks by weathering processes. The document outlines the formation of magma from heat and pressure conditions in the Earth's interior and how magma crystallizes into igneous rocks as it cools on the surface or in the crust.
Metamorphic rocks
Metamorphic rocks are formed from existing rocks through heat and pressure within the Earth. This process, called metamorphism, changes the hardness, texture, and layering of the original rocks. There are different types of metamorphism that result in various metamorphic rock formations. Metamorphic rocks exhibit features like foliation, lineation, and different textures depending on the grade of metamorphism experienced. Common metamorphic rocks include slate, phyllite, schist, gneiss, quartzite, and marble.
Petrology
Petrology is the study of rocks and their composition, texture, and structure. There are three main types of rocks: igneous rocks, which form from cooling magma; metamorphic rocks, which form from existing rocks undergoing changes due to heat, pressure, and chemical reactions; and sedimentary rocks, which form from the compaction and cementation of sediments. Igneous rocks can be categorized as extrusive or intrusive, depending on where they solidify. Common igneous rocks include granite, basalt, and syenite. Sedimentary rocks form through the weathering of existing rocks and the deposition and lithification of sediments. Texture, minerals, and formation processes help classify and identify different
Presentation-Earthandlifescience-3-1.pptx
Metamorphic rocks form from the transformation of existing rock subjected to high temperatures and pressures. The original, unmetamorphosed rock is called the protolith. Metamorphic rocks are classified based on their protolith, chemical makeup, texture as either foliated or non-foliated. Foliated metamorphic rocks have a parallel alignment of minerals giving them a banded or layered appearance, while non-foliated rocks lack visible banding due to uniform pressure during metamorphism or blocky mineral composition. Common examples of each include slate and marble.
Metamorphic rocks bs 1st year
Metamorphic rocks are formed from pre-existing igneous, sedimentary, or other metamorphic rocks through the process of metamorphism. Metamorphism involves changes to a rock's mineralogy, texture, and sometimes chemical composition due to changes in temperature, pressure, and exposure to chemically active fluids. The degree of metamorphism can range from slight changes resulting in low-grade metamorphic rocks like slate to more substantial changes producing high-grade metamorphic rocks. Common agents driving metamorphism include heat, pressure, and chemically active fluids.
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Migmatites
- 2. MIGMATITES * Introduced by - SEDERHOLM (1907). * Meaning - Mixed rock. * It have some condtions to forms they are -Temperature -Pressure * It forms near a large intrusions of granite when some magma is injected into the neighboring metamorphic rock. * It may classified as some various terms Paleosome - unaltered parent rock Neosome - newly formed rock Leucosome - containing felsic minerals Melanosome - containing mafic minerals ( biotite, hornblende, garnet etc.,) Mesosome - Rock portion of a migmatite, intermediate between leucosome and melanosome. * Migmatites may sometimes classified as !!- METATEXITES - Low degrees of melting !!- DIATEXITES - High degrees of melting
- 4. STRUCTURES OF MIGMATITES * Dietzonitic structure * Schollen structure * Phlebitic structure * Stromatic structure * Surreitic structure * Agmatic structure * Folded structure * Pigmatic structure * Optalmic structure * Stictolithic structure
- 5. 1. DIETONITIC STRUCTURE - Net like structure. - Paleosome interlocked by net like narrow veins of neosome.
- 6. 2. SCHOLLEN STURUCTURE - Rift like structure. - Paleosome is partially dissolved in the neosome and showing distict borders.
- 7. 3. PHLEBITIC STRUCTURE - Vein like structure. - Veins of light coloured neosome traversing dark colored paleosome.
- 8. 4. STROMATIC STRUCTURE - Layered like structure. - Leucosome and neosome are occurs in parallel. - flows not entirely even.
- 9. 5. SURRETIC STRUCTURE - Diliation like structure - In paleosome, leucosome is occurs like crystal arranged seems like foliated.
- 10. 6. AGMATIC STRUCTURE - Breccia like structure. - Agma means fragments - Veins of neosome intrude in the paleosome. Try
- 11. 7. FOLDED STRUCTURE - Formed by the compressional pressure acting on a rock. - Bending of layers.
- 12. 8. PTYGMATIC STRUCTURE - The fold at the top is thin and the bottom is thick.
- 13. 9. OPTHALMIC STRUCTURE - Augen like structure. - Neosome occupies within the paleosome. - Eye like structure.
- 14. 10. STICOLITHIC STRUCTURE - Fleck like structure - Rarely occured - Mafic minerals are concentrated, thus the result of some pore in the mafic minerals.
- 15. FIELD RELATION & OCCURANCE : * It associated with metamorphic rock of the HIGH TEMPERATURE part of the amphibolite facies and granulite facies. * Fact of metamorphic geology is the close association in the field of HIGH GRADE METAMORPHIC ROCK.
- 16. MIGMATITE PHYSICAL PROPERTIES • Hardness is 5.5-6.5. • Streak is white colour. • Fracture is irregular. • Lustier is dull to pearly to subvitreous. • Poor cleavage. • Specific gravity is 2.65-2.75. • Opaque in nature. • Grain size is medium to fine coarse grain. • Porosity is very less.
- 17. USES OF MIGMATITES • Cement manufacture. • For road aggregate. • Building stones. • Sometimes being polished for ornaments. THANK YOU