Earth Mat Flashcards - Ch 7
Differentiate Holocrystalline, Hypocrystalline, and Holohayaline
Wholly crystal, half crystal half glass, and wholly glass respectively
how large are pegmatites and what influences their formation
more than 30 mm, influenced by volatile amount
different grain sizes of phaneritic texture
coarse 10-30 mm
medium 3-10
fine 1-3
The process of which liquids are cooled to temperatures under the liquidus
Undercooling
it is produced when ions form bonds during crystal formation and in turn, the main reason why seed crystals that just nucleated are remelted again
Heat of formation
it is the rate at which elements migrate through magma
Diffusion
elements that increase molecular linkage, and elements that decrease these linkages
network formers and modifiers respectively.
it is a type of glassy igneous rock containing cristobalite seed crystals
Snowflake Obsidian
an igneous texture wherein higher amounts of trapped water results in a cloudy form of obsidian
Perlitic texture
a process in which volatiles nucleate into small bubbles
Vesiculation
it is a location wherein bubbles constitute 70-80% of the magma volume
Fragmentation surface
how do the amounts of vesicles influence the naming of rocks
pumice or scoria - more than 30%
vesicular - 5-30%
vesicle bearing - less than 5%
Secondary fluids precipitating in vesicles
Amygdules
aka airbourne pyroclastics
Tephra
types of welded tuffs
unwelded tuffs - Random shard orientation
partially welded tuff - paarallelism among shards
densely welded tuffs - withflattening and parallelism
statistics of Si and O and the major elements relative to its abundance on Earth
75% Crust weight
94.7% volume
other elements constitute 25% weight and 5.3% volume
as for the major elements: 99.2% weight
examples of minor elements and which minor elements are present in mafic and felsic rocks
minor elements: 0.1-1% abundance
Cr, Mn, P, H, Ti
Mafic: Cr, Ni, Cu
Felsic: Li, Ba, Be
it is the solid residual rock
Restite
enumerate the LREEs and HREEs
LREEs: La, Ce, Pr, Nd, Sm
HREEs: Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu
enumerate the LILEs and HFSEs
HFSEs: (immobile) Ti, Ni, Cr, V, Zr, Hf, Nb, Ta, Y
less than 0.2 radius/charge ratio
LILEs: (mobile) Cs, Ba, Rb, Sr, U, Pb, K, Zr, Th, Ta
greater than 0.2 radius/charge ratio
Europium positive anomaly in a system signifies the presence of?
Plagioclase
what does Sr87/Sr86 ratio differentiate?
it differentiates various magma environments
less than 0.7028 - ocean floor
0.7039 - ocean islands
0.7044 - island arcs
what are the abundances of major minerals and accessory minerals
major - greater than 5% abundance in a rock
accessory - less than 5% such as oxides, sulfides.
it is the first normative mineralogy classification
CIPW (Cross, Iddings, Pirsson, Washington) norm classification
what are the Relative abundances terms for Aluminum relative to Alkalis?
Peraluminous - Al> Alkali metals
Metaluminous -Na + K < Al < Ca, Na, K
Subaluminous - Al = Na +K
Peralkaline - Al < Na + K
Requirements to have QAPF and TAS diagram eligible of use
QAPF - more than 10% felsic minerals and less than 90% mafic minerals
TAS - Less than 2% water, and 0.5% Carbon dioxide
