Term
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Definition
| Occur during crystallization and result from interaction between minerals and the melt |
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Term
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Definition
| Are alteration that take place after the rock is completely solid |
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Term
| Principle of crystal growth |
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Definition
| 1) nucleation. 2) Growth 3) diffusion of chemical species and heat |
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Term
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Definition
| the phenocrysts contain small inclusions of another mineral that they enveloped when they grew |
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Term
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Definition
| the host crystal in a piokilitic textured rock |
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Term
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Definition
| crystals take branching tree-like form |
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Term
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Definition
| crystal that corners and edges grew more rapidly |
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Term
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Definition
| preferred nucleation of a mineral on another preexisting mineral |
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Term
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Definition
| plag overgrowths on orthoclase – occurs in granites |
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Term
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Definition
| occurs when a mineral changes composition as it grows during cooling (common in plag.) |
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Term
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Definition
plag progresses from a anorthite-rich (Ca) core
to an albite-rich (Na) rim – expected zonation from cooling |
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Term
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Definition
| plag progresses from a more sodic (Na) core to a calcic (Ca) rim |
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Term
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Definition
| : is the most common type of zoning in plag because a regular decrease in anorthite (An) content rarely dominates the full crystallization history |
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Term
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Definition
| grains that are bounded on all sides by crystal faces |
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Term
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Definition
| are grains that are bounded by some crystal faces; and |
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Term
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Definition
| grains are devoid of crystal faces |
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Term
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Definition
| refers to the envelopment of plag. laths by larger clinopyroxene with little or no associated glass |
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Term
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Definition
| (smaller px’s that still partially envelope the plag) |
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Term
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Definition
| (plag and px crystals are sub-equal in size and glass is still relatively minor) |
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Term
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Definition
| an intergrowth of quartz and alkali feldspar |
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Term
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Definition
| reflect a re-fusion ir dissolution of a mineral back into a melt |
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Term
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Definition
| either deep & irregular embayments, advanced resorption, or rapid growth capturing melt |
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Term
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Definition
| Flow within a melt can result in alignment of elongated or tabular minerals - |
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Term
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Definition
| crystals are too small to see by eye |
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Term
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Definition
| can see the constituent minerals |
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Term
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Definition
| term for very course grained size |
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Term
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Definition
| composed of pieces of igneous material (typically from explosive volcanism) |
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Term
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Definition
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Term
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Definition
| if the texture displays two dominant grain sizes (bimodal distribution) |
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Term
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Definition
| larger crystals in porphyritic rocks |
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Term
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Definition
| finer crystal matrix in porphyritic rocks |
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Term
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Definition
| no crystals, even in thin section |
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Term
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Definition
| {feldspar + Silica} quartz, plagioclase, k-feldspar, muscovite |
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Term
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Definition
| {magnesium + FERRIC iron} biotite, hornblende, pyroxene, olivine |
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Term
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Definition
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Definition
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Term
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Definition
| clusters of adnearing phenocrysts |
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Term
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Definition
| felty texture, non-alignment of of microlites |
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