Day 2 Purgatory Flashcards
can determine whether a suite of rocks is related through a process such as magmatic differentiation or mixing.
Major element geochemistry
is used to identify the role various minerals may have played as either crystallizing phases or residual phases in a suite of rocks.
Trace element geochemistry
and stable isotopes, can determine whether a suite of rocks formed from a single magma, or whether a more complex, multisource process was involved.
Isotope geochemistry
What does the AP line in the QAPF plot represent
line of SiO2 saturation
contain complete crystal faces that are not impinged upon by other crystals
Euhedral
contain partially complete crystal forms in which at least one of the crystal faces is impinged upon by adjacent rock material
Subhedral
crystals lack any observable crystal faces
Anhedral
contain small crystals less than 1 mm in diameter that are not generally discernible to the eye
Aphanitic
characterized by large crystals averaging more than 30 mm in diameter
Pegmatite
igneous rock that consist of two distinctly different size crystals
Porphyritic
frequently used to refer to volcanic materials ejected from a volcanic vent
Pyroclastic
fragments form by mechanical friction during movement of lava and breakage of cool brittle
outer margins, or gravity crumbling of spines and domes Reworking
Autoclastic Fragments
Volcaniclastics that are formed by magma-water interaction
Hydroclasts
clasts of volcanic composition derived from erosion of volcanoes or ancient volcanic terrane with no volcanic edifice
Epiclasts
Nearly molten bombs, usually basaltic, that readily weld upon impact to form agglutinate
Splatter
Less vesicular than pumice sinks in water more mafic than pumice no size limitations
Scoria
Lapillus size particles formed by concentric accretion of ash
Accretionary Lapilli
Particles ( lithic, vitric) derived from new magma
Essential (juvenile)
Particles derived from earlier eruptions at same volcanic center
Accessory (Cognate)
Particles of any origin or composition from rocks through which the vent penetrates
Accidental
grains with rectangular tablet shapes
tabular
if the rock contains numerous holes that were once occupied by a gas phase, then
vesivular
a texture consisting of intergrowths of quartz and alkali feldspar wherein the orientation of the quartz grains resembles cuneiform writing
Graphic
grains that have all of their boundaries of approximately length
Equant
describe grains that show an abundance of
prism faces
prismatic
if phenocrysts are found to occur as clusters of crystals, then the rock should
be described as
Glomeroporphyritic
if vesicles are so abundant that they make up over 50 of the rock and the rock has a
density less than 1
Pumiceous
if vesicles are so abundant that they make up over 50 of the rock and the rock has
a density greater than 1 then the rock is said to be
Scoriaceous
an intergrowth of quartz and plagioclase that shows small wormlike bodies of quartz enclosed in plagioclase This texture is found in granites
Myrmekitic
laths of plagioclase in a coarse grained matrix of pyroxene crystals, wherein the plagioclase is totally surrounded by pyroxene grains This
Ophitic
the plagioclase grains are not completely enclosed in a matrix of pyroxene grains
Subophitic
smaller grains of one mineral are completely enclosed in large, optically
continuous grains of another mineral
Poikilitic
a texture in which the angular interstices between plagioclase grains
are occupied by grains of ferromagnesium minerals such
Intergranular
a texture similar to intergranular texture except that the interstices
between plagioclase grains are occupied by glass or
Intersertal
Symmetry of Cubic Systems
4 3-fold axes
Symmetry of Tetragonal Systems
1 4-fold axes
Symmetry of Hexagonal Systems
1 6-fold axes
Symmetry of Trigonal Systems
1 3-fold axes
Symmetry of Orthorhombic Systems
3 2-fold axes
Symmetry of Monoclinic Systems
1 2-fold axes
Symmetry of Triclinic Systems
1 1fold axes
Shale, sandstone and limestone together form 95% of the sedimentary rock
95%
Shale comprises ____of the sedimentary crust, sandstone_____, and
limestone
66.5%
19%
9.5%
A galoon of sea water contains about ____ oz of salt
4.7 oz salt
results from metasomatism of granitic rocks
greisen
results from metasomatism of peridotite
serpentinite
results from high-grade regional metamorphism of basalt
Eclogite
Low P Moderate T, contact metamorphism facies
Ab-Ep Hornfels
Low P, Mod to high T, contact metamorphism facies
Hb Hornfels; Px Hornfels
Low P, high T, contact metamorphism facies
Sanidinite
Mod T, low P regional metamorphic facies
Prenite-Pumpellyite, Zeolite
Mod T, low to med P regional metamorphic facies
Greenschist
Mod T, med to high P regional metamorphic facies
Amphibolite
Mod T, high to very high P regional metamorphic facies
Granulite
Very high to High T, Low P Metamorphic Facies
Blueschist
Very high to High T, High P Metamorphic Facies
Eclogite
Diganostic mineralogy of Zeolites
Qtz + Laumontite + Chl
Diganostic mineralogy of Prenite-Pumpellyite
Prenite + Pumpellyite
No zeolites, glaucophane or Lawsonite
Metagraywackers: Albite +Prenite + Pumpellyite + Qtz + chl + spene
Diganostic mineralogy of Blueschist
Glaucophane + Lawsonite
Diganostic mineralogy of Greenschist
Characteristic Bluschist minerals absent
Basics : ab + ep + chl + act + cal
Pelitic : chl + mus + bio + chloritoid +- Pyrophyllite
Diganostic mineralogy of Amphibolite
Disappearance of Albite
Basic: hbl + plag(oligo and andesine); ep and alamandine
Pelitic: micas w/ alamandinte, Staurolite, Kya, Silimanite
Diganostic mineralogy of Granulite
Basic : Dio + Hypersthene +plag
Pelitic : Silimanite/Kyanite + perthitic felds + alamandine + cordierite
Diganostic mineralogy of Ecolgiote
Basic : cpx + al-py garnet,
No feldspar
Facies under Regional metamorphism
Zeolite, Prehnite-Pumellyite, Blueschist, Greenschist, Amphibolite, Granulite, Eclogite
Diganostic mineralogy of Ab-Ep Hornfels
Basic : ab + chl + actinolite
Diganostic mineralogy of Hb Hornfels
Basic : hbl + plag with ep or al
Pelitic: mica + andalusite, cordierite or silimanit
no kyanites
Diganostic mineralogy of Px Hornfels
Basic : diop+ hypersthene + plag, no Amphiboles
Pelitic : silimanite + cor with Kfelds, No muscovite
Marble : Wollastonite + Cal + forsterite + Perclase
Diganostic mineralogy of Sanidinite
Trdymite, Mullite, Monticellite, Larnite, Sanidine
What would be the contact metamorphic counterpart of amphibolite in terms of mineralogy
Ab-Ep Hornfels
What would be the contact metamorphic counterpart of greenschist in terms of mineralogy
Hb Hornfels; Px Hornfels
What would be the contact metamorphic counterpart of granulite in terms of mineralogy
Px Hornfels
Fe-Mg content of felsic magma
2%
Fe-Mg content of intermediate magma
3%
Fe-Mg content of mafic magma
4%
Fe-Mg content of ultramafic magma
8-32%
- Phase boundary (line) that separates the all-liquid (melt) stability field from stability fields that contain at least some solid (crystals)
Liquidus
- Phase boundary (line) that separates the all-solid (crystal) stability field from stability fields that contain at least some liquid (melt)
Solidus
Condition under which liquid (melt) is in equilibrium with two different solids
Eutectic
Condition under which a reaction occurs between a pre-existing solid phase and a liquid (melt) to produce a new solid phase.
Peritectic
- Occurs when melts of the same composition are produced by melting rocks of different initial composition.
Invariant meting
Occurs when a solid mineral phase melts to produce a melt and a different mineral with a different composition from the initial mineral.
Incongruent melting
- Mineral crystals and melt react to produce a completely different mineral; negligible solid solution exists between the minerals.
Discontinuous reaction
Mineral crystals and melt react to continuously and incrementally change the composition of both; requires a mineral solid solution serie
Continuous reaction
Phase boundary (line) that separates conditions in which complete solid solution occurs within a mineral series from conditions under which solid solution is limited.
Solvus
Two components of Igneous Petrology and Definition
Igneous Petrography: description and classification of igneous rocks
Igneous Petrogenesis: Study of the origin and evolution of igneous rocks.
Division of common minerals according to the IUGS classification
Q = Quartz
A = Alkali Felds
P = Plagioclase
F = Feldspathoids
How does the upper portion of the QAPF differ from the bottom
Upper portion : Silica Saturated
Lower Portion : Silica Undersaturated
In what kind of igneous rock is the QAPF applicable, in what kind it isnt
<90 % mafic, >90% Mafic
Criterias in classifying igneous rocks
Minerals Presentr
Texture
Color
Chemical Composition
Large crystals in a porphyritic rock are referred to as _____________, finer grained material constitutes the __________
Phenocryst, Groundmass
What does texture refer to in the context of petroology
igneous rock’s crystal size, shape/form, and degree of crystallinity.
Primary v Secondary Textures
Primary: forms during crystallization and results from the interactions of the melt and crystals
Secondary: formed due to alterations that take place after the rock is completely solid
Nucleation
clustering of a critical size of compatible ions
Undercooling
cooling of the melt way below the true crystallization temperature of the mineral
What does fabirc refer to in the context of petroology
the mutual relationship between the grains
idiomorphic granular
most of the grains are euhedral
hypidiomorphic granular
most of the grains are subhedral
allotriomorphic granular
most of the grains are anhedral
Vesicular
if the rock contains numerous holes that were once occupied by a gas phase,
Amygdular
if vesicles have been filled with material
Spherulitic
found in glassy rhyolites wherein spherical intergrowths of radiating quartz and feldspar replace glass
Obicular
restricted to coarser grained rocks that consists of concentrically banded spheres wherein the bands consist of alternating light colored and dark colored minerals
Anorthosites can be found in,
Tonalites, Diorite, Gabbros, Dacite, Basalts
Bywotonite can be found in
Granodiorite, Monozodirites, Monzogabbro, Dacite, Andesite,
Labradorites can be found in
Granodiorite, Monozodirites, Monzogabbro, Dacite, Andesite,
Andesines can be found in
Rhyolites, Trachytes, Latites, Granite, Syenites and Mozonites
Oligoclase can be found in
Rhyolites, Trachytes, Latites, Granite, Syenites and Mozonites
Albite can be found in
Alkali felds granite and syenites, Alkali Felds rhyolite and trachyte
The deposition order of minerals in a setting where sea water evaporates
Calcite,
Gypsum or Anhydrite,
Halite
Transgressive seas exhibit a carbonate-shale-sandstone sequence that
progressively migrates toward land.
Zeolite group of minerals
AHSLW
Analcime
Heulandite,
Stillbite
Laumontite
Wairakite
Pelitic Definition
metamorphosed fine-grained sedimentary rock, i.e. mudstone or siltstone.
The zeolite and prehnite-pumpellyite facies result
from the burial of graywacke, shale, and malic volcanic rocks in a eugeosynclinal environment (i.e. subduction zones).
Regionally metamorphosed rocks of the blueschist (also called glaucophane schist) facies develop in a
tectonically active eugeosynclinal environment along the continental margin.
Greenschist facies develop in
a geosynclinal environment that has a normal geothermal gradient.
The high-temperature boundary between the greenschist and amphibolite facies is marked by the disappearance of _____ as the amphibolite facies is entered.
albite
Amphibolite facies rocks typically are found ___
underlying the greenschist facies in orogenic belts.
Granulite facies are the
highest-grade metamorphic rock formed at normal geothermal gradients.
Asbestos minerals found in amphiboles
ACTAA
Amosite
Crocodilite
Tremolite
Actinolite
Anthophyllit
Asbestos mineral found in sepentines
Chrysotile
Pyroclastic deposit with >64 mm for pyroclast, unconsolidated tephra, consaolidated pyroclastic rock
Bomb, Block
Agglomerate
Pyroclastic Breccia
Pyroclastic deposit with 2 - 64mm for pyroclast, unconsolidated tephra, consaolidated pyroclastic rock
Lapillus
Lapili Tephra
Lapilistone
Pyroclastic deposit with 1/16 - 2 mm for pyroclast, unconsolidated tephra, consaolidated pyroclastic rock
Fine Ash (Pyroclasts and Tephra
FineTuff
Pyroclastic deposit with < 1/16 or pyroclast, unconsolidated tephra, consaolidated pyroclastic rock
Coarse Ash (Pyroclasts and Tephra
Coarse Tuff
Degrees of Crystalinity and definition
Holocrystalline : wholly crystalline
Hypocrystalline: partially crystalline/partially glassy
Holohyaline: wholly glassy
Subdivisions of Phaneritic rocks
Fine (1-3mm)
Medium (3-10mm)
Coarse (10-30mm)
If a granitic rock has more than 50% phenocrysts, what would be its classification. What about less than 50% phenocrysts
Granite Porphyry; Porphyritic Granite
Factors that affect the texture of igneous rock
Diffusion rate : rate at which atoms or molecules can move through the liquid
The rate of nucleation: chemical constituents of a crystal can come together in one place without dissolving
Crystal Growth Rate: new constituents can arrive at the surface of the growing crystal
In which part of the nucleation and growth rate curves produces a phaneritic texture. Sketch the graph
High growth, low nucleation
In which part of the nucleation and growth rate curves produces a aphanitic texture. Sketch the graph
Low growth, high nucleation
In which part of the nucleation and growth rate curves produces a holohyaline texture. Sketch the graph
Low growth, low nucleation
Magma Generation
- Increase of temp by radioactivity or heat flux (hot spots)
- Adiabatic decompressions (morbs)
- Addition of volatiles (subduction zones)
Mohs Scale for common items
2.5 fingernail
3.5 copper penny
5.5 pocket knife
6.5 steel file
Pyroclastic debris
0-25 % Blocks and Bombs
75 - 100 % Lapili
Lapili-stone
Pyroclastic debris
0-25 % Blocks and Bombs
25 - 75 % Lapili
Lapili-Tuff
Pyroclastic debris
0-25 % Blocks and Bombs
0-25 % Lapili
Tuff
Pyroclastic debris
25 - 75 % Blocks and Bombs
0 - 100 % Lapili/Ash
Tuff-Breccia
Pyroclastic debris
75 - 100 % Blocks and Bombs
0 - 100 % Lapili/Ash
Pyroclastic Breccia
