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igneous rocks texture - Coggle Diagram
igneous rocks texture
glassy玻璃岩理
fractures conchoidally貝殼狀斷口
rapid cooling of lava
common felsic igneous rocks
obsidian黑曜石- felsic volcanic glass
tachylite 玄武玻璃 - bubble-free, mafic (>80%) glass
pumice 浮石 - frothy felsic rock full of vesicles; it floats
scoria 火山渣 - glassy, vesicular mafic rock
porphyritic texture斑狀岩理
two-stage cooling history
initial slow cooling creates phenocrysts斑晶
mixture of coarse and fine crystals
fragmental碎屑岩理
pyroclastic debris
igneous chunks
interlocking嵌合岩理
texture
phaneritic顯晶質(coarse-grained)
slow cooling
crystals have a long time to grow
intrusive
aphanitic隱晶質(fine-grained)
extrusive
rapid cooling
crystals do not have time to grow
composition
intermediate中性火成岩
mafic基性火成岩
felsic酸性火成岩
ultramafic超基性火成岩