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Are sedimentary rocks that form when minerals come out of a solution classified as porphyritic?
No. I believe they are called chemical precipitate sedimentary rocks. Yes, I'm sure they're called that. Absolutely! Porphyritic is a term usually applied to igneous rocks, having to do with mineral formation and rock texture.
What are rocks containing two different sizes of crystal called?
Such rocks are porphyritic.
Is porphyritic texture is not a feature of sedimentary rocks?
Correct, porphyritic texture is typically associated with igneous rocks and is not a common feature of sedimentary rocks. It is characterized by larger crystals, known as phenocrysts, surrounded by a fine-grained or glassy matrix. Sedimentary rocks are formed through the accumulation and lithification of sediments, which do not typically undergo the same crystallization processes as igneous rocks.
Is felsic porphyritic extrusive?
Felsic porphyritic rocks can be extrusive if they are formed from volcanic eruptions. These rocks have a high silica content and typically contain large crystals (phenocrysts) embedded in a fine-grained matrix. Examples of felsic porphyritic extrusive rocks include rhyolite and dacite.
What Mineral alignment in a metamorphic rock usually gives the rock a porphyritic texture?
A porphyritic texture can be a feature of igneous rocks, but 'porphyritic' is not used to describe metamorphic rock texture. Metamorphic rocks can be foliated or non-foliated, terms used to describe mineral alignment or banding, or the lack thereof.
What are the crystal structures in porphyritic rocks?
Porphyritic rocks typically have a porphyritic texture, where large crystals (phenocrysts) are embedded in a finer-grained matrix (groundmass). The crystal structures within porphyritic rocks can vary depending on the minerals present, but common examples include feldspar, quartz, and mica minerals. These minerals can form a variety of crystal structures such as monoclinic, triclinic, or hexagonal depending on their composition and arrangement of atoms.
Which igneous rock cools the fastest glassy aphanitc pegmatic and porphyritic?
Glassy igneous rocks cool the fastest. The most likely had more nucleation. Pegmatic cooled the slowest, which is why its crystals are larger than 1 cm. Phaneritic is the next slowest in cooling. Porphyritic has slow then rapid cooling, while aphanitic igneous rocks also have rapid cooling.
What is porphyritic texture and what sequence of events produces porphyritic textures in rocks?
Porphyritic texture is a characteristic of igneous rocks where large crystals, known as phenocrysts, are embedded in a finer-grained groundmass or matrix. This texture forms through a two-stage cooling process: initially, magma cools slowly underground, allowing larger crystals to form, and then it erupts or ascends to the surface where it cools rapidly, crystallizing the remaining minerals into a finer-grained texture. The contrast in crystal sizes is a key feature of porphyritic rocks, indicating the different cooling rates experienced during their formation.
What is the cooling rate of a porphyritic rock?
The cooling rate of a porphyritic rock can vary depending on the specific conditions during its formation, but generally it is considered to be intermediate. This means that porphyritic rocks cool at a moderate rate, which allows for the formation of both large crystals (phenocrysts) and finer-grained matrix.
What igneous rocks are both intrusive and extrusive?
The igneous rocks that can be both intrusive and extrusive are known as porphyritic rocks. These rocks form when magma partially cools underground (intrusive) before being erupted onto the Earth's surface where the remaining magma cools quickly (extrusive). This dual cooling process creates distinctive textures in the rock, with larger crystals (phenocrysts) embedded in a finer-grained matrix.
This igneous texture is characterized by two distinctively different crystal sizes?
The igneous texture characterized by two distinctively different crystal sizes is known as porphyritic texture. Porphyritic rocks have larger crystals (phenocrysts) surrounded by a fine-grained matrix (groundmass), indicating two different stages of cooling within the magma.
Is granite rock porphyritic?
Granite rock is not porphyritic. It is phaneritic because it has a coarse-grained texture.
