#igneouspetrology — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #igneouspetrology, aggregated by home.social.
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Igneous rock (Volcanology 🌋)
Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial melts of existing rocks in a terrestrial planet's mantle or crust. Typically, the melting is caused by one or more of three proce...
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Lithophysa (Mineralogy 💎)
A lithophysa is a felsic volcanic rock with a spherulitic structure and interior cavity with concentric chambers. Its outer shape is spherical or lenticular. They vary in size from very small up to twelve feet in diameter depending on the age of the magma chamber. These rocks are usually found within obsidian or rhyolite lava flows. Lavas low in feldspar ...
https://en.wikipedia.org/wiki/Lithophysa
#Lithophysa #Mineralogy #Volcanology #VolcanicRocks #IgneousPetrology
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Point counting (geology) (Geology ⛰️)
In geology, point counting is a method to determine the proportion of an area that is covered by some objects of interest. In most cases the area is a thin section or a polished slab. The objects of interest vary between subdisciplines and can for example be quartz or feldspar grains in sedimentology, any type...
https://en.wikipedia.org/wiki/Point_counting_(geology)
#PointCounting #Geology #Petrology #Geostatistics #IgneousPetrology #GeologicalTechniques
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Flow banding (Volcanology 🌋)
Flow banding is a geological term to describe bands or layers that can sometimes be seen in rock that formed from magma. Flow banding is caused by friction of the viscous magma that is in contact with a solid rock interface, usually the wall rock to an intrusive chamber or, if the magma is erupted, the surface of the Earth across which the lav...
https://en.wikipedia.org/wiki/Flow_banding
#FlowBanding #Volcanology #IgneousRocks #IgneousPetrology #StructuralGeology
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@FaithfullJohn I've the first edition (published 1980) that was the textbook for learning igneous petrology back sometime in the 1980's...
#IgneousPetrology #PhaseDiagrams #Basalts #ExperimentalPetrology
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This week's #NewBooks at the library: Second-hand copies of The Theory of #Evolution: Principles, Concepts, and Assumptions from The University of Chicago Press; An Intimate History of Evolution: The Story of the #Huxley Family from Allen Lane (sans dustjacket); and Mind Over Magma: The Story of #IgneousPetrology from @princetonupress #Books #Scicomm #Bookstodon #HistoryOfScience #ScienceHistory #HistSci #EarthSciences #Geology
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Lithophysa (Volcanology 🌋)
A lithophysa is a felsic volcanic rock with a spherulitic structure and interior cavity with concentric chambers. Its outer shape is spherical or lenticular. They vary in size from very small up to twelve feet in diameter depending on the age of the magma chamber. These rocks are usually found within obsidian or rhyolite lava flows. Lavas low in feldspar...
https://en.wikipedia.org/wiki/Lithophysa
#Lithophysa #Mineralogy #Volcanology #VolcanicRocks #IgneousPetrology
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Normative mineralogy (Mineralogy 💎)
Normative mineralogy is a calculation of the composition of a rock sample that estimates the idealised mineralogy of a rock based on a quantitative chemical analysis according to the principles of geochemistry. Normative mineral calculations can be achieved via either the CIPW Norm or the Barth-Niggli Norm. Normative calculations are used t...
https://en.wikipedia.org/wiki/Normative_mineralogy
#NormativeMineralogy #Mineralogy #Geochemistry #IgneousPetrology
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@geologymull An excellent photo of basaltic quench glass (tachylite). I've not seen tachylite in person... It does look like the rock is leaking tar.
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Andesite line (Volcanology 🌋)
The andesite line is the most significant regional geologic distinction in the Pacific Ocean basin. It separates the mafic basaltic volcanic rocks of the Central Pacific Basin from the partially submerged continental areas of more felsic andesitic volcanic rock on its margins. The andesite line parallels the subduction zone...
https://en.wikipedia.org/wiki/Andesite_line
#AndesiteLine #Petrology #Volcanology #PlateTectonics #IgneousPetrology #HistoryOfEarthScience
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Bowen's reaction series (Volcanology 🌋)
Within the field of geology, Bowen's reaction series is the work of the Canadian petrologist Norman L. Bowen, who summarized, based on experiments and observations of natural rocks, the sequence of crystallization of common silicate minerals from typical basaltic magma undergoing fractional crystallization. Bowen's reaction series is able to exp...
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Andesite line (Volcanology 🌋)
The andesite line is the most significant regional geologic distinction in the Pacific Ocean basin. It separates the mafic basaltic volcanic rocks of the Central Pacific Basin from the partially submerged continental areas of more felsic andesitic volcanic rock on its margins. The andesite line parallels the subduction zone...
https://en.wikipedia.org/wiki/Andesite_line
#AndesiteLine #Petrology #Volcanology #PlateTectonics #IgneousPetrology #HistoryOfEarthScience
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QAPF diagram (Petrology 💎)
A QAPF diagram is a doubled-triangle plot diagram used to classify intrusive igneous rocks based on their mineralogy. The acronym QAPF stands for "Quartz, Alkali feldspar, Plagioclase, Feldspathoid ", which are the four mineral groups used for classification in a QAPF diagram. The percentages of the Q, A, P and F groups are normalized, i.e., recalculated so that th...
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Basalt exposure at Calavera. #geology #igneouspetrology This doesn’t appear on any map, but is a clear complication to the site geology.
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#ThinSectionThursday A vision of volcanic loveliness 🌋 🥰 in this porphyritic phonolite from the Canary Islands. Big crystals of sodium-rich amphibole, Na-Fe clinopyroxene titanite, apatite, nepheline, and zircon, in a finer-grained groundmass mostly of sanidine feldspar, and nepheline/glass. Field of view ca. 2mm wide. #Geology #IgneousPetrology #Microscopy