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When metamorphic rocks undergo pressure, how are they changed?

Metamorphic rocks are formed when a rock (sedimentary, igneous or a previous metamorphic rock) comes under high pressure and/or temperature. Pressure and temperature forces the atoms to form new ...
user2821's user avatar
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Which geological processes will destroy plastic?

Some simplifying assumptions This is quite a broad and complex question to answer, so I'm going to simplify it shamelessly to make it a little more answerable. Firstly, there are a huge number of ...
Pont's user avatar
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What causes compositional banding in metamorphic rocks?

There are several different ways in which gneissic banding can form. The three most common mechanisms are: Preservation of banding from source material: Consider a protolith that already contains ...
Zenopsis's user avatar
4 votes

What is the age of the earliest traces of life on Earth?

The oldest (fairly) definitive fossils date from about 3.48 billion years ago (Ga) and consist of sedimentary structures associated with microbial mats living in coastal environments.[1] Beyond this ...
bon's user avatar
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When metamorphic rocks undergo pressure, how are they changed?

Metamorphic rocks are changed by transformations deep underground. Being deep underground there is immense pressure and heat. The transformations can be just crystal size of the particular mineral, ...
MaxW's user avatar
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How can you infer the burning degree (Celcius etc) of a wood from a heat effected specimen?

There has been a recent study about this: Pensa et al. (2023) used charcoal samples found in the deposits of the 79 CE eruption of Mount Vesuvius to infer the temperature of its pyroclastic density ...
Jean-Marie Prival's user avatar
2 votes

When metamorphic rocks undergo pressure, how are they changed?

Metamorphic can have been halfway to the state of lava for a short time, it may have been like quite tough dough of bread. You can imagine the viscosity of it to be the same as ordinary glass which is ...
bandybabboon's user avatar
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When metamorphic rocks undergo pressure, how are they changed?

The existing answers are correct but I think they miss an important aspect of your question, which is the effect of pressure. Do they become fragments of rocks? No. Fragmentation of rocks is a ...
Gimelist's user avatar
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Where can I find papers on the geology of the Wastach Range in Utah

This report on the stratigraphy is probably a good place to start. Additonally, searching Google Scholar for Wasatch Range geochronology brings up a number of papers on the geochronology of specific ...
bon's user avatar
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Is there any mineral that survives hard degree metamorphism?

Zircon is one mineral which survives metamorphism. Zircons can survive processes like erosion, transport and metamorphism, so they preserve a record of past geological processes. From Wikipedia, ...
Fred's user avatar
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2 votes

Isotopic dating of metamorphic rocks

There are two ways (at least two I will discuss here) to date a metamorphic rock. The first is using an isochron. During a heating event, isotope ratios between different minerals (most often used are ...
Gimelist's user avatar
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1 vote

Isotopic dating of metamorphic rocks

The main objection with regard to sedimentary rock is that you can date the individual mineral grains with isotopic techniques but not when they were laid down together. All metamorphic rocks show ...
Ash's user avatar
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Any recommendations for a good online lecture series on Metamorphic Petrology

ClassCentral.com, SouthAlabama.Edu, ndsu.com, ocw.mit.edu You can learn a lot from these sites.
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When sediments are deposited, do they sink into the earth?

The podcast may have given the impression that sediment always gets buried or pushed down into the earth. This isnt the reality of the processes which are dynamic and dependent on geologic time as ...
Armondo Villaescuza's user avatar
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What is the metamorphic field gradient useful for?

You are entirely correct. Todd and Engi write: The mineral assemblages of rocks at the surface lie on a locus of P–T-conditions… It must be stressed…does not imply a P–T-distribution or geotherm ...
Gimelist's user avatar
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1 vote

Does grade of metamorphism apply to igneous and sedimentary rocks?

Metamorphic "grade" ONLY applies to metamorphic rocks; the "grade" referring to how much pressure and temperature the rock, be it sedimentary, igneous, and even metamorphic, has been subjected to. ...
Knob Scratcher's user avatar
1 vote

Does grade of metamorphism apply to igneous and sedimentary rocks?

I'm not sure I entirely understand your questions but I'll have a go. Does grade of metamorphism apply to igneous and sedimentary rocks? Yes. Both igneous and sedimentary rocks can be ...
Gimelist's user avatar
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are laccolith, lobolith, dikes and sills formed of porphyritic texture?

Laccoliths, lopoliths, dikes and sills are all characteristic modes of occurrence of hypabyssal rocks, generally small in scale compared to most magma chambers. They are magmas which have cooled in a ...
Gordon Stanger's user avatar

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