Key Definitions Flashcards
minerals, igneous rocks
mineral
naturally occurring substance having a definite composition and crystalline structure
rock
aggregate or mixture of one or more minerals
sublimination
the transition of a substance directly from solid to gas whithout passing the intermidiate liquid phase
lusture
surface appearance, as it interacts with light
crystal
a solid wit plane faces formed when atoms are arranged in a structurally ordered pattern
glass
an amorphous solid with no crystalline structure
grain boundary
the line of contact between mineral crystals in a rock
cations
atoms that have lost electrons leaving them with a net positive charge
anions
atoms that have gained electrons leaving them negative
covalent bond
formed by the sharing of a pair of electrons
tetrahedron
a solid contained by 4 triangular plane faces
solid solution
describes two end member crystals with defined compositions, within which one or more atoms may be substituted for the original atom in a solid state, without changing the structure and allowing varied compositions between the end members
bridging oxygen
an oxygen atom shared by two SiO4 tetrahedra in a crystal structure
polymers
consist of repeating chains of smaller molecules (monomers)
magma accumulation
magma collecting in a magma chamberin
intrusions
igneous rock formed below he earths surface, magma forced into pre-existing rocks
extrusions
the emission of magma onto the earths surface where is forms a lava flow
foliation
a texture in metamorphic rocks formed by the pre-alignment of flat/tabular minerals
deposition
the laying down of sediment that occurring when transporting agent loses energy
weathering
the breakdown of rocks in situ
erosion
the removal of weathered material, usually by physical actions of transported fragments
transport
weathered material is moved from one place to another by: wind, water, ice or gravity
uplift
the return of buried rocks to the earths surface by tectonic forces
igneous rocks
rocks cooled from magma
phenocrysts
large crystals in an igneous rock, much larger than the groundmass
essential mineral
minerals used to classify igneous rocks- other minerals may be present by aren’t used for classification
felsic minerals
light coloured, silica rich
magma
molten rock, beneath the earth surface
mafic minerals
dark coloured, silica poor and rich in magnesium and iron
flow banding
formed by friction as the magma or lava slows down near an interface, aligning the minerals as it moves
conchoidal
fracture which results i a curved surface
vesicular
a rock which contains vesicles- gas bubbles which came out of solution as a result of pressure release
porphyritic
phenocrysts completely surrounded by a ground mass
equigranular
crystals in a rock are approximately the same size
amygdaloidal
large vesicles have been filled with a secondary material
lava
molten rock that cools at the surface
ophiolites
sections of the earths oceanic crust that have been tectonically moved onto continental crust
hypabyssal
igneous rocks forming at relatively shallow depths below the surface
plutonic
igneous rocks forming deep below the surface
euhedral
crystals are well formed wit good crystal faces