Term
| Igneous rocks (ignis = fire) |
|
Definition
| Rocks that form as molten rocks that cool and solidify. ROCKS FORMED FROM MAGMA. |
|
|
Term
|
Definition
| Magma that crystallizes at depth |
|
|
Term
|
Definition
| Molten material consisting of liquid (melt), solid (silicate minerals), and gas (water vapor, carbon dioxide, and sulfur dioxide) components. |
|
|
Term
|
Definition
| FLUIDS - especially water. The parts in the melt that vaporize at surface pressure. Causes rock to MELT AT LOWER TEMPERATURES. Stays with magma until it researches or comes close to the surface or starts to crystallize |
|
|
Term
| RATE at which magma cools, amount of SILICA present , amount of dissolved GASES in the magma |
|
Definition
| Three factors that affect crystal size. |
|
|
Term
| Aphanitic texture (a = not , phaner = visible) |
|
Definition
| Igneous rocks that form at the surface or as small masses within the upper crust where cooling is relatively rapid. RESULTS IN FINE-GRAINED TEXTURE. |
|
|
Term
|
Definition
| Rocks with voids left by gas bubbles at escape as lava solidifies |
|
|
Term
| Phaneritic texture (phaner=visible) |
|
Definition
| COARSE-GRAINED TEXTURE as a result of magma slowly solidifying below the surface |
|
|
Term
|
Definition
| Large crystals(phenocrysts) embedded in a matrix of smaller crystals (groundmass) |
|
|
Term
|
Definition
| Molten rock ejected into the atmosphere during a volcanic eruption results in VERY RAPID COOLING - called obsidian. |
|
|
Term
|
Definition
| CONTINENTAL. GRANITIC rocks that are rich in silica. LIGHTer and less dense. Low viscosity (THIN). Highest silica content (70%+) |
|
|
Term
|
Definition
| OCEANIC. BASALTIC composition rich in ferromagesian minerals. High iron content = DARKer and denser. High viscosity (THICK) |
|
|
Term
|
Definition
| Measurement of RESISTANCE of a fluid. Refers to the thickness of it. Thin liquid = low; Thick = high |
|
|
Term
| Pyroclastic (fragmental) Texture |
|
Definition
| Igneous rocks formed from individual rock fragments ejected during a volcanic eruption that come together and solidify. Common type known as WELDED TUFF - composed of fine glass fragments that FUSE TOGETHER upon impact |
|
|
Term
|
Definition
| Exceptionally COARSE-GRAINED igneous rocks. Made up of interlocking crystals larger than a centimeter in diameter. The crystals are NOT results of prolonged cooling but being a fluid-rich environment in which ION MIGRATION IS ENCHANCED. Found around margins of large PLUTONS as SMALL masses or THIN veins. |
|
|
Term
| Intermediate / ANDESITIC and/or DIORITIC |
|
Definition
| ANDESITIC Composition. IN BETWEEN granitic and basaltic. Has 25% basaltic minerals and is has a dominant felsic mineral: plagioclase feldspar. |
|
|
Term
|
Definition
| PERIDOTITE- igneous rock containing mostly olivine and pyroxene. OPPOSITE to Felsic(GRANITIC) rocks. RARE on surface, but main component of upper mantle. Very low silica content (45%) |
|
|
Term
|
Definition
| Combine silicon (S) and oxygen (O). They are the two most ABUNDANT elements in igneous rocks. Lowest in ultramafic, highest in felsic. |
|
|
Term
|
Definition
| Change in temperature with DEPTH. EX: temp. at 100 km can range from 1200- 1400 degrees Celsius. Temperatures get hotter as you go deeper. |
|
|
Term
|
Definition
| The factor of the state of matter a rock is in. Produced by: increase in DEPTH, FRICTION from subduction zones (huge slabs of crust slide past each other), hot mantle RISING and intruding crustal rocks. |
|
|
Term
| Heat, Pressure, and Volatiles. |
|
Definition
| Three factors that generate Magma |
|
|
Term
|
Definition
| When pressure drops enough so that rock turns from solid to liquid. |
|
|
Term
|
Definition
| Increases with depth. Can melt rock when accompanied with an increase in volume. Melts at high temperature at depth because of this. INCREASING this INCREASES rocks melting point. Meaning more elevating a rock is the hotter it needs to be to melt it. |
|
|
Term
|
Definition
| Confining pressure. Increase in this can cause an increase in rock's melting point. Decrease in this causes rock's melting point to decrease. |
|
|
