Crater Lake - GEOL 4321 Crater Lake 1. The fiammi is easily...

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GEOL 4321 Crater Lake 1. The fiammi is easily distinguishable from lithic clasts by textures and grain sizes. The fiammi is a fine grained eutaxitic glass that was once pumice, but has been compressed do to heat and the overlying pumice. The fiammi is actually compressed around the lithics. Because the fiammi consists of glass, it is best seen in PPL. The fiammi exhibits a flow characteristic around the lithic grains. The lithic grains often have a bimodal distribution of grainsizes (porphyritic), containing crystals of pyroxenes and plagioclase with a plagioclase ground mass. Other lithics may be only a single lath of plagioclase. 2. L3-6 and CL-LL-1 are both mafic enclaves representing a mafic magma that was injected into and mingled with the host felsic magma. The texture of the boundaries between the enclaves and the felsic glass consists of a dark mafic glass that is lobate in form. The enclaves primarily consist of plagioclase and hornblende. If the enclave was either an accidental xenoliths or cumulates of earlier magma, you would expect the boundaries to be more jagged or sharp without the dark mafic glass. The lobate boundaries can be
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Crater Lake - GEOL 4321 Crater Lake 1. The fiammi is easily...

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