DAY 2 Mineralogy Flashcards
when did the mohs scale established
1824
when was mohs hard scale invented?
1894
who invented the mohs scale?
frederic m
who invented the mohs scale?
frederic mohs
who invented mohs scale
frederic mohs
how man
transition elements within crystal lattices that can change the color of a mineral
chromophores
transition elements within crystal lattices that can change the color of a mineral
chromophores
how many silicates in mohs scale
4 talc orthoclase feldspar quartz topaz
how many hydrous in mohs scale
4 talc gypsum apatite topaz
how many hexagonal in mohs scale
calcite apatite quartz corundum
how many isometric in mohs scale
2 fluorite and diamond
how many isometric in mohs scale
2 fluorite and diamond
how many orthorhombic in mohs scale
1 topaz
how many monoclinic in mohs scale
3 talc gypsum orthoclase feldspar
how many orthorhombic in mohs scale
1 topaz
how many isometric in mohs scale
2 fluorite and diamond
ratio of velocity of light in air and the velocity of light in a medium
refractive index
this has a single refractive index
isotropic minerals
more than one refractive index
anisotropic minerals
property of a mineral that can produce a “double image” of an object behind the mineral due to light passing through the mineral having two polarized rays vibrating at right angles from each angle
double refraction
minerals that are deformed through compressive stress
malleable
also called hypdiomorphic hypautomorphic sub idioblastic
suhedral
also called allotriomorphix xenomorphic xenoblastic
anhedral
smallest unit of pattern that when repeated by a set of symmetry operations will generate the long range pattern characteristics of crystal
motif
point used to represent any motif
node
set of rules that govern the repetition of motifs which can produce two or three dimensional patterns with long range order
symmetry operations
specific length and direction of systematic displacement by which the pattern is repeated
unit translation vector
smallest units of meshes which contains at least one node and the unit translation vectors
unit meshes
groups denoted by their rotational and reflection symmetry
plane point groups
combines translation parallel to an axis with rotation about the axis
screw rotation
how many plane lattice groups
17
recognized groups that are based on the total symmetry of their plane lattices
plane lattice groups
3d equivalents of the 2d plane point groups
space point groups
3d patterns of points produced from the translation of nodes of space point groups
space lattices
defined on the basis of the external symmetry of mineral crystals and belong to six crystal systems with its own characteristic symmetry
crystal classes
parallelipiped whose edge lengths and volume are defined by the 3 unit translation vectors
unit cell
orientation of the unit cell edge
crystallographic axes
consists of a 3d set of one or more crystal faces that possess similar relationship to the crystallographic axes
crystal forms
encloses a mineral specimen and exist alone in perfectly formed euhedral crystals and also include all forms in the isometric system and many forms in the tetragonal hexagonal trigonal and orthorhombic systems
closed crystal form
what are the crystal class of isometric?
hexoctahedral
hextetrahedral
gyroidal
dipyroidal
tetraoidal
what are the crystal class of tetragonal?
ditetragonal-dipyramidal
ditetragonal-pyramidal
tetragonal scalenohedral
tetragonal trapezohedral
tetragonal dipyramidal
tetragonal disphenoidal
tetragonal pyramidal
what are the crystal class of hexagonal?
dihexagonal dipyramidal
dihexaginal pyramidal
ditrigonal dipyramidal
hexagonal trapezohedral
hexagonal dipyramidal
hexagonal pyramidal
trigonal dipyramidal
crystal class of rhombohedral/trigonal
hexagonal scalenohedral
ditrigonal pyramidal
trigonal trapezohedral
trigonal pyramidal
rhombohedral
crystal class of orthorhombic?
rhombic ipyramidal
rhombic pyramidal
rhombic disphenoidal
crystal class of monoclinic?
prismatic
sphenoidal
domatic
crystal class of triclinic?
pinacoidal
pedial
consists of a single face
pedion
a pair of parallel faces
pinacoid
has 3 parallel to an axis
prism
has 3 or more faces that intersect at an axis
pyramid
a pair of faces symmetrical about a mirror plane
dome
pair of faces symmetrical about an axis of rotation
sphenoid
proportional lengths of the 3 crystallographic axes
axial ratio
also called unit face any face that intersects all 3 axes at distances from the center that correspond to the axial ration of the mineral
unit plane
method describing the relationship between sets of crystal faces or planes and the crystallographic axes that are always expressed in the sequence a b c where each represents their respective axes generally k k l where each represent a b and c axis
weiss parameters
the reciprocal of any faces or set of planes weiss parameters written as hkl that represents the reciprocal of the face of the planes of the weiss parameters of the a b and c axis respectively
miller indices
what are the forms under isometric
cube 001 6 square faces halite galena pyrite fluorite
octahedron 111 8 triangular faces spinel magnetite chromite diamond
dodecahedron 011 12 diamond shaped faces garnet sphalerite sodalite cuprite
tetrahedron 111 4 triangular faces tetrahedrite sphalerite
pyritohedron h0I 12 pentagonal faces pyrite
forms under tetragonal
tetragonal dipyramid 111 hh1 011 8 triangular faces with top 4 separated from bottom 4 by mirror plane zircon rutile cassiterite wolfenite
tetragonal prism 0kl and variations 4 rectangular faces parallel to c axis scheelite vesuvianite malachite azurite
tetragonal disphenoid 0kl 4 triangular faces with alternation pairs symmetrical about c axis chalcopyrite
basal pinacoid 001 pair of faces perpendicular to c axis vesuvianite wolfenite
forms under hexagonal
hexagonal dipyramidal 1121 12 triangular faces inclined to c axis with top 6 separated from bottom 6 by mirror plane apatite zincite
hexagonal prism 1120 6 rectangular faces parallel to c axis apatite quartz tourmaline
basal pinacoid 0001 pair of faces perpendicular to c axis beryl corundum
forms under trigonal?
rhombohedron 6 parallelogram faces inclined to c axis dolomite siderite rhodochrosite
trigonal scalenohedron 23 scalene triangle faces inclined to c axis calcite
trigonal prism 3 rectangular facs parallel to c axis tourmaline quartz calcite
trigonal dipyramid 6 triangular faces top 3 separated from bottom 3 by a mirror plane tourmaline
orthorhombic forms?
rhombic pyramids 8 triangular faces top 4 separated from bottom 4 by a mirror plane topaz aragonite olivine
rhombic pyramids 4 rectangular faces parallel to a single crystallographic axis stibnite celestite enstatite
pinacoids 2 parallel faces perpendicular to a b or c axis andalusite hemimorphite barite
monoclinic forms?
monoclinic prisms 4 rectangular faces gypsum staurolite clinopyroxene
pinacoids 001 010 110 pair to rectangular perpendicular to a b c axis sphene epidote micas
triclinic forms?
pinacoids 2 parallel faces kyanite plagioclase microcline
pedions single face rhodonite wollastonite
what is the weight of a nucleus and protons
1.00867 amu nucleus
1.00728 amu protons
who developed the periodic table of elements
dmitri mendeleev march 1 1869
the amount of energy required to strip an element of an electron from its outermost shell
ionization potential
mineral groups that has no group or subgroup?
antimonides sb^3
arsenates asO4^3
arsenides As^3
borates BO3^3 BO4^-3
chromates CrO4^-2
molybdates MoO4^-2
nitrates NO3^-1
phosphates PO4^-2
selenides Se^-2
sulfides S-2
tellurides Te-2
Tungstates WO4^-2
Vanadates VO4^-2
what are the mineral groups of carbonates?
calcite group CO3^-2
dolomite group
aragonite group
groups under the mineral group halides
anhydrous halides
hydrous halides CL-1 Br1 F1
what are the subgroups under hydroxides?
brucite type group
gibbsite type group OH1
what are the groups under native element
metals group:
gold group
platinum group
iron group
semimetals group
non metals group
groups under oxides?
simple oxides group:
protoxide subgroup XO-2, X2O-2
rutile subgroup XO2^-2
hematite group X2O3^-2
complex oxides group:
spinel group XY2O4^-2
iron subgroup chromite subgroup O-2
groups under silicates?
nesosilicates island silicates 1:4:
olivine garnet aluminum silicates group SiO4^-4
sorosilicates double island silicates 2:7:
Epidote group Si2O7^-6
cyclosilicates ring silicates- 1:3:
beryl tourmaline group Si2O7^-6
inosilicates chain silicates - 1:3:
pyroxene single Si2O6^-4 amphibole double silicate Si4O11^-6
phyllosilicates sheet silicates 2:5:
mica group serpentine clay chlorite Si2O5^-2
tectosilicates framework silicates 1:2:
silica feldspathoid plagioclase feldspar potassium feldspar group scapolite zeolite SiO2
groups under sulfates?
anhydrous sulfates
hydrous sulfates SO4^-2
this theory suggests that beams of light consist of material particles that spread in all directions from luminous bodies
corpuscular theory
particle of lights which are discrete packets of energy that interact with atoms at the subatomic level
photons
assumes that units of quanta radiates discontinuously from radiating oscillators in a black body
quantum theory
surface that represents the direction of the propagation of light energy simultaneously in same place
wavefront
line at any point in the direction of the propagation of light perpendicular to the surface of a wave front
wave normal
perpendicular to the wavefront represents the direction of propagation of light
ray of light
materials whose light passing through them have light rays parallel to the wave normal and perpendicular to the wavefront
isotropic
light passing have light rays that are not parallel to the wave normal
anisotropic
curve that may represent that combined movement around a circle with movement along a straight line
displacement
component of light found on the wavefront that is perpendicular to the light ray in isotropic materials but is only perpendicular in limited directions for anistropic materials
vibration direction
filters the light and eliminate the orange light
base
blue filter
polarizes light in a single wave direction generally only those oriented in the N-S direction
sub stage
polarizer (lower polarizer)
controls the amount of light passing through the specimen
sub stage
iris diaphragm
controls and focuses the light from the light source
sub stage
condenser
used to retard the light coming through the specimen
intermediate
accessory plates
polarizes light in a single wave direction only those in the E-W direction
intermediate
analyzer (upper polarizer)
used to observe interference figures
intermediate
bertrand lens
magnifies the observed image
intermediate
objective lens
adjusts the stage’s distance from the objective lens
stand
coarse adjustment knob
focuses and sharpens observed image
stand
fine adjustment knob
let’s users to observe the image produced
Assembly: Ocular
Part: Eyepiece
ratio of the wave normal velocity in a vacuum regardless if the medium is isotropic or anisotropic
refractive index
light consists of a single wavelength
monochromatic light
component of light vector that lies parallel to the wave front and perpendicular to the direction of the propagation except for anisotropic minerals
light vector
light vector that measures the electrical displacement
electric light vector
measures magnetic displacement
magnetic light vector
147nm retardation dimensions are usually NW-SE
mica plate
550nm retardation dimensions are usually NW-SE
gypsum plate
various retardation to determine the order of the interference color exhibited by a mineral
quartz wedge
optically positive if the interference color between the melatope ; negative if melatope
decreases; increases
optically positive if the colors move in along the trace of the OAP and out along the ON
negative if the colors MOVE OUT along the trace of the OAP and in along the ON
monoclinic variety of albite
monalbite
lapiz lazuli, chalcedony amazonite and jasper were cut and curved where?
babylonia
it is also known an emerald filter
chelsea
also called flame fusion, was the first commercially successful method of manufacturing synthetic gemstones, developed in the late 1883
Verneuil method
also called as crystal pulling
Czochralski process
heavy walled steel cylinder closed at one end
autoclave or bomb
a process for growing single crystal or crystals of a metal or compounds. ruby and emerald are grown here
Flux method
which materials dyeing used
chalcedony jade and turquoise
gems successful for heat treatment
zircon quartz beryl topaz and zoisite (tansanite)
clinonet is also known as what?
clinonet
what is called as german silver?
iron nickel zinc
equation describing the relationship of than angle of incidence and angle of refraction with the refractive index of the light in air and in the medium and predicts that incident light that is not perpendicular to the surface of the medium will always be refracted in the medium
snells law
degree of visibility of a transparent mineral in an immersion medium or the difference between the refractive index between a mineral and a medium
relief
difference between RI of the mineral and the surrounding medium that involves a halo around the boundary of the mineral grain, and becomes either less or more visible as you increase the free working distance by defocusing the microscope
becke line method
difference between the RI of the mineral and the surrounding medium that involves blocking parts of the light and observing the shadow of the mineral grain. The RI of the mineral is higher than the surrounding medium if the shadow is on the lighted part of the visible field while it is lower when its shadow is on the darkened part of the visible field
oblique illumination method
composed of two rays
cross polarized light
travels in the low refractive index direction
fast ray
travels in high refractive index
slow ray
measured in number of wavelengths and it is the amount by which the slow rays lag behind the fast ray. It is proportional to the birefringence and to the distance traveled through the specimen
retardation
twinning where two crystals form as penetration twins
carlsbad twinning
lamellae are both observed with respect to each other and every alternate twin plate or slab has an identical atomic structure
lamellar twinning
two kinds of repeated twinning in thin sections with one set of twins arranged at 90 to other set
tartan twinning
outer rim is composed of low temp mineral compared to its center which is composed of high temp mineral of the same solid solution
normal zoning
outer rim is composed of high temperature mineral compared to its center which is composed of low tem mineral of the same solid solution
reverse zoning
step like progression of higher temp mineral tot he lower temp mineral at margins with local reversals in adjacent zones
oscillatory zoning
minerals extinct at certain angles that may be due to being deformed
undulatory extinction
systematic pattern of chemical variations from solid solution which starts at the periphery of the crystal towards the center regarding an incomplete continuous chemical reaction between the crystal and surrounding melt
zoning
divisions in the michel levy chart for every 550um that is marked by a reddish hue interference color
order
lens inserted below the oculars used to observe interference figures
bertrand lens
bands of interference colors which increases in order form the melatope to the outer bands
isochrome
arms of the interference figure
isogyre
point where the isogyres cross and where the optic axis emerges
melatope
specific direction in anisotropic minerals where only one ray travels through the mineral
optic axis
is a sphere and indicatrix with constant radius due to light travelling in all directions with the same velocity
isotropic indicatrix
an ellipsoid that revolves around the crystals c axis optic axis
uniaxial indicatrix
anisotropic minerals where minerals with tetragonal and hexagonal crystal system belong which have only one optic axis
uniaxial minerals
semi axis perpendicular to the c axis that has length proportional to the RI perpendicular to c and is associated with the ordinary light
omega
one of the two rays refracted when light entered uniaxial minerals and always moves parallel to the c axis which is parallel tot he crystals c axis and is always perpendicular to the extraordinary ray
ordinary ray
semi axis parallel to the c axis that has a length proportional to the RI parallel to c and is associated with the extraordinary ray
epsilon
one o fthe two rays refracted when light entered uniaxial minerals and moves anywhere between perpendicular to nearly parallel to the ordinary wave and is always perpendicular to the ordinary ray
extraordinary ray
intermediated refractive indices possessed by intermediate velocities of epsilon that are associated with other e ray directions
epsilon prime
perpendicular to the optic axis the c axis and ordinary ray path
circular section
viewed when the optic axis is parallel to the stage which is parallel to the extraordinary wave vibration direction
principal section
other section parallel to the stage that have two rays pass through the crystal path ans is associated with epsilon prime
random sections
a sign that denotes ray is associated with either the larger or smaller refractive index
optic sign
uniaxial minerals that are geometrically prolate that occurs when the epsilon which is the slow ray and associated with the larger refractive index and is more than the omega whish is the fast ray associated with the smaller refractive index
uniaxial positive
uniaxial minerals that are geometrically prolate that occurs when the epsilon which is the slow ray and associated with the larger refractive index and is lesser than the omega whish is the fast ray associated with the smaller refractive index
uniaxial negative
an accessory plate used for minerals with low birefringe in order to determine their optic sign by retarding the ineral by 550um or specifically one order
gypsum plate
observed when the optic axis is perpendicular to the stage so that the circular section is parallel to the stage
centered uniaxial optic axis OA figure
observed when the optic axis is inclined more steeply than 60 - 70 degrees with respect tot he stage making a random section parallel to the stage
off centered optic axis OA figure
observed when the optic axis lies within the plane of the stage making a principal section being viewed thus both the omega and epsilon vibration directions being observed. The flash figure will be observed every 90 degrees rotation of the stage when the optic axis is parallel to one of the two polarizing lenses
uniaxial flash figure
a triaxial ellipsoid the represents the refractive indices of a biaxial mineral in every direction
biaxial indicatrix
class of anisotropic minerals where minerals are triclinic monoclinic and orthorhombic crystals systems belong which have only two optic axes
biaxial minerals
minimum refractive index in the biaxial indicatrix that is associated with the short axis of the ellipsoid X parallel to the vibration direction of the fast ray
alpha
minimum refractive index in the biaxial indicatrix that is associated with the long axis of the ellipsoid Z parallel to the vibration direction of the slow ray
gemma
intermediate refractive index in the biaxial indicatrix that is associated with the intermediate axis of the ellipsoid Y associated with the vibration direction of an intermediate ray
beta
elliptical XY plane
optic plane
elliptical XZ plane perpendicular to the Y
elliptical XZ plane perpendicular to the Y
optic axial plane
circular sections in a biaxial indicatrix that are perpendicular to the two sections
optic normal sections
the angle between the optic axes measured in optic plane
optic angle 2V
line parallel to the y axis of a biaxial indicatrix that intersects the optic normal sections
optic normal
line in the optic plane that bisects the optic angle between the optic axes
optic normal
complementary line that bisects the optic angle that may either 2Vx or 2Vz depending on the mineral optics
acute bisectrix bxa
accessory plate used for minerals with high birefringence to easily determine their optic signs
quartz wedge
biochemical sedimentary rocks that contain more than 15% by weight and occur in rocks that range in age from 3.8 Ga to the present
iron rich bichemical sedimentary rocks
constitutes 60% of the iron ores
banded iron formation
type of BIf dominate the archean iron rich sedimentary rocks that formed between 3.8 ga and 2. 6 ga
algoma type BIF
dominate the proterozoic iron rich sedimentary rocks the formed between 2.6 GA and 1.8 Ga and again 0.8 Ga to 0.5 Ga and are supposedly much larger compared to algoma type
superior type BIF
iron formation contained superior type of BIF which formed in fairly shallow water environments on passive continental shelves with limited influx of detrital sediments
granular iron formation
most widespread type of phanerozoic iron rich sedimentary rock that are quite thin and are composed predominantly of goethite and hematite with smaller amounts of iron bearing chlorite mineral chamosite
ironstone
contain less than 30% gravel sized clasts and sand mud ratio of <1:1 in their detrital fraction
mudrocks
smectite rich that formed from the alteration of volcanic as deposits from explosive eruptions
bentonite
at what temp and pressure does diagenesis occur?
~150 +- 50 degrees celcius and ~0.3 kbar
early shallow diagenesis that occurs shortly after burial
eodiagenesis
later deeper diagenesis
mesodiagenesis
even later and shallow diagenesis that occurs as sedimentary rocks approach the surface due to erosion
telodiagenesis
diagenetic product of plastic grains that can be difficult to distinguish from detrital matrix constituents
pseudomatrix
most abundant group of biochemical sedimentary rocks and constitute about 15% of all sed rocks
carbonates
also called as allochems sand to gravel sized carbonate particles that include shells ooids and limeclasts and peloids
grains
also called as allochems sand to gravel sized carbonate particles that include shells ooids and limeclasts and peloids
grains
mud sized carbonate particles in limestones and dolostones
micrite
process where micro boring activity of blue green cyanophyt texture
micritization
emphasizes the texture of carbonate rocks
dunham classification
emphasizes thecomponents of carbonate rocks
folks classification
carbonate rocks with gravel sized particles
calcirudite/dolorudite
carbonate rocks with sand sized particles
calcarenite/dolarenite
carbonate rocks with mud sized particles
calcilutite/dololutite
composed of lithified colluvium deposited from mass wasting
diamictite
less than 30% gravel sized clasts and a sand:mud ratio of >1:1 in their detrital fraction
sandstones
sandstones containing 75-95% quartz grains with F:L ratio 1:>1
subarkose
sandstones containing 75-95% quartz grains with F:L ratio of 1:> 1
sublitharenite
rock fragment rich sandstones
lithearenite
contains less than 75% quartz grains with F:L ratio between 1:1 to 3:1
lithic arkose
contains less than 75% quartz grains with F:K ratio between 1:1 to 1:3
feldspathic litharenite
how many percent is sed rocks in earths surface
85%
quick method of determining the phi size value for any percentile
sorting coefficient
more complicated measure of sorting that involves finding values that are one standard deviation and two standard deviations above and below the mean
inclusive graphic standard deviation
rod shaped particles that have an elongate cylindrical that have on axis much longer than the other two
prolate
disk shaped particles that have a flattened cylindrical or disk like shape where two saxes are shorter than the other two
oblate
particles that have a flattened shape where the 3 axes have 3 different lengths
bladed
gravelstones with an interior source eroding from the same source and lithifying in place making the clasts and matrices compositions uniform
intraformational
compositions derived outside of depostional basin with the clasts and matrices composition different from each other
extraformational
more than 90% of the framework clasts consisting of a single or few resistant rocks and minerals
oligomict
clasts of different compositions that are prone to weathering and erosion
petromict
clasts composed of a single composition
monomictic
2-4 different types of parent rocks
diamictic
clasts with numerous amounts of types of composition
polymictic
the total overall retardation is greater than that exhibited prior to the accessory plate being inserted
positive elongation
what are the isotropic minerals with low relief
halite
halloysite
antigorite
cliachite
collophane
what are the isotropic minerals with moderate relief
opal
fluorite
lechatelierite
sodalite
analcime
hauyne
what are the isotropic minerals with moderate to strong relief
periclase
garnet group
grossularite
pyrope
almandite
spessarite
uvavorite
andradite
what are the isotropic minerals with very high relief
limonite
spinel
chromite
perovskite
sphalerite
do not affect the polarization direction of the light which has passed through lower polarizer
isotropic minerals
will appear dark or extinct every 90 degrees of rotation of the microscope stage
anisotropic minerals
produce elongate grains and cleavage are distinguishable
biotite hornblende plag
production of plane polarized refractive index
nicol prism
minerals that exhibit parallel extinction
orthopyroxene biotite
minerals that exhibit inclined extinction
clinopyroxene hornblende
minerals that exhibit symmetrical extinction
amphibole calcite
minerals that exhibit no cleavage
quartz olivine
measures double refraction
snells law
how many known minerals
4000 but 50 are common
refractive index varies inversely with wavelength snells law
dispersion of light
cleavage exhibits 56- 124 degrees
amphibole group
two segments of one grain go extinct at different times as the stage is rotated
simple twins
the segments are joined by a smooth twin plane separating the segments
contact twins
the segments are joined by an irregular contact
penetration twins
consists of numerous twin segments joined on parallel twin planes
polysynthetic twinning
the separation of a single homogeneous mineral into two or more distinct minerals in the solid state
exsolution or unmixing
ex: perthite albite exsolution from orthoclase at about 56 degrees celsius
successive layers of sheet structure show regular variations in their orientation occurs in micas and clay
polytypism
this mineral is colorless not pleochroic anhedral no cleavage very low relied uniaxial and length is slow
quartz
colorless but cloudy
not pleochroic
subhedral to anhedral
2 cleavage directions
low relief
biaxial
carlsbad and tartan twinning
alkali feldspars
colorless no pleochroic
euhedral to anhedral
perfect cleavage directions
low relief
weak birefringence
polysynthetic albite carlsbad pericline twinning
triclinic feldspars
plag felds
An0 to An10
albite
an90- an100
anorthite
intergrowth where soda rich phase predominates over potash rich phase
antiperthite
their atomic ration exceeds that of alkali feldspars
feldspathoids
nepheline
sodalite
leucite
colorless
not pleochroic
high relief
no to poor cleavage
strong birefringence
parallel extinction
length slow
olivine
F065-FO0
fe rich igneous rock
colorless and weakly pleochroic
2 cleavage directions at 87 and 93 degrees
stubby crystals
bery high relief
weak to moderate birefringence
parallel inclined symmetric extinctions
pyroxenes
orthorhombic orthopyroxenes
enstatite bronzite hypersthene ferrosilite
monoclinic ca mg fe pyroxenes
augite pigeonite diopside hedenbergite
sodic pyroxenes
aegerine-jadeite
colored with varying pleochroism
slender crystals
high relief
2 cleavage directions
mod to strong birefringence
parallel inclined symmetric
amphibole
mg fe amphiboles
antophyllite-cummingtonite-grunerite
ca fe mg amphiboles
tremolite-actinolite-hornblende
sodic amphiboles
glaucophane-ribeckite-arvedsonite
various shades of brown with tinges of red and green
highly pleochroic
1 perfect basal cleavage
fair relief
strong birefringenece
high interference color
parallel inclinced
biaxial
biotite
minute crystals usually tabular or prismatic habit and birefringent
microllites
smaller spherical rod like and hair like isotropic forms
crystallites
an aphanitic or glassy texture that are completely free of phenocrysts
aphyric
some are euhedral subhedral rest are anhedral
granitic structure
all are anhedral
aplitic texture
phenocrysts are gathered distinct clusters
glomeroporphyritic
monomineralic clusters in a glomeroporphyritic texture
glomerocrysts
polyminerallic clusters in a glomeroporphyritic texture
cumulocrysts
continuous ranges of size in crystals of the principal minerals in a fine grained matrix
seriate
broken series of sizes
hiatal
relatively large crystal of one mineral (oikocryst)
enclose numerous smaller crystals of one or more other mineral (chadacryst) which are randomly oriented oikocryst is the latest to finish crystallizing
poikolitic
randomly arranged plagioclase chadacrysts are elongate and ate wholly poikolophitic enclosed by the augite oikocryst
ophitic
glass occupies wedge shaped interstices between plan laths
intersertal
spaces between plag laths are occupied by one or more grains of pyroxene olivine or opaque minerals
intergranular
other term for euhedral
idiomorphic
automorphic
other term for subhedral
hypidiomorphic
hypoautomorphic
other term for anhedral
xenomorphic
allotriomorphic
subparallel arrangement of microcystalline lath shaped feldspars in groundmass
trachytic
trachytic texture with crystalline material in between feldspars
pilotaxitic
trachytic texture with cglassy material in between feldspars
hyalopilitic
subparallel arrangement of tabular bladed or prismatic crystals which are visible to the naked eye
trachitoid
dense holocrystalline tightly appressed microlites generally of feldspars interwoven in irregular unoriented fashion
felty
boundary involves interdigitations
consertal
form a eutectic mixture or through replacements similar to cuneiform writing
graphic
patches of plag felds intergrown with vermicular qtz
mermyktic texture
intimate intergrowth of 2 minerals in which one mineral has a vermicular
symplectite texture
composed of an aggregate of fibtrous crystals radiating from a nucleus with glass or crystals in between
spherulitic
radiate texture with radiating fibers extending from either end if linear nucleus rahter than a point
axiolitic
radiate texture with fanlike arrangement of divergent often branching fibers
variolitic
crystal of one mineral is surrounded by a rim or mantle of one or more crystals of another mineral
corona
corona texture charac by an overgrowth by NA plag on large K felds
rapakivi
charac by an overgrowth of pyroxene of hornblende or olivine or garnet
kelyphitic
one or more concentric bands ina single crystal are picked out by lines of inclusions or by gradual or abrupt changes in solid solution
zoning
charac having dips or bay like section in thte crystals as a result of resorption disequilibrium
embayed
how many space groups are determined?
230 space groups
4-faced form where the faces
are related by mirror planes
Rhombic Pyramid
4-faced form where the faces
are related by a 4 axis
Tetragonal Pyramid
8-faced form where all faces
are related by a 4 axis.
Ditetragonal Pyramid
o 12-faced form where all
faces are related by a 6-fold
axis. This form results from
mirror planes that are parallel
to the 6-fold axis
Dihexagonal Pyramid
are closed forms consisting of 6, 8,
12, 16, or 24 faces. Dipyramids are
pyramids that are reflected
across a mirror plane. Thus, they
occur in crystal classes that have
a mirror plane perpendicular to a
rotation or rotoinversion axis
Dipyrami
are closed 6, 8, or 12 faced forms,
with 3, 4, or 6 upper faces offset
from 3, 4, or 6 lower faces.
Trapezohedrons
closed form with 8 or 12 faces. In
ideally developed faces each of
the faces is a scalene triangle. In
the model, note the presence of
the 3-fold rotoinversion axis
perpendicular to the 3 2- fold axes
Scalenohedrons
6-faced closed form wherein 3
faces on top are offset by 3
identical upside down faces on
the bottom, as a result of a 3-fold
rotoinversion axis.
Rhombohedrons
closed form consisting of 4 faces.
These are only present in the
orthorhombic system (class 222)
and the tetragonal system (class )
Disphenoids
A hexahedron is the same as a
cube. 3-fold axes are
perpendicular to the face of the
cube, and four axes run through
the corners of the cube.
Hexahedron
8 faced form that results form
three 4-fold axes with
perpendicular mirror planes. The
octahedron has the form symbol
{111}and consists of the following
8 faces: (111), (), (11), (1), (1), (1),
(11), and (11).
Octahedron
12-faced form. Dodecahedrons
can be formed by cutting off the
edges of a cube. The form symbol
for a dodecahedron is {110}.
Dodecahedron
12-faced closed form with the
general form symbol {hhl}. This
means that all faces intersect two
of the a-axes at equal length and
intersect the third a-axis at a
different length
Trapezohedron
occur as accessory
minerals in igneous and
metamorphic rocks and as
resistant detrital grains in
sediments
Oxides
Includes the majority of ore
minerals
Sulfides
adjacent silica tetrahedra share
oxygens to form the different types of
silicates
polymerization
describes the
phenomena of polarization, reflection,
refraction and interference, which form
the basis for optical mineralogy
Wave theory
In isotropic materials the Wave Normal
and Light Ray are?
parallel
A measure of how effective a material is in bending light is called
Index of Refraction (n)
used to calculate
how much the light will bend on
travelling into the new medium
Snell’s law
in which minerals are seen with pleochroism?
tourmaline, biotite, hornblende, (most
amphiboles), some pyroxenes.
The ability to selectively
transmit and absorb light is termed
pleochroism
involves the determination
of the refractive index of minerals, using
the immersion method.
Refractometry
This method relies
on having immersion oils of known
refractive index and comparing the
unknown mineral to the oil.
Refractometry
the degree to which a mineral
grain or grains appear to stand out from
the mounting material, whether it is an
immersion oil, Canada balsam or another
mineral
Relief
the indices of the
mineral and surrounding medium
differ by greater than 0.12 RI units.
Strong relief
indices differ by 0.04 to 0.12 RI units
Moderate relief
Indices differ by or are within 0.04 RI
units of each other
Low relief
what is the index of oil
1.45
It is a band or rim of light visible along the grain boundary in plane light when the grain mount is slightly out of focus.
Becke Line
exhibits parallel extinction
inclined
symmetrical
orthopyroxene biotite
Clinopyroxene, Hornblende
amphibole; calcite
become familiar with this plate, it
produces ~550 nm of retardation.
The interference colour in white
light is a distinct magenta colour.
This colour is found at the boundary
between first and second order
colours on Plate 1. First Order Red Plate)
Gypsum Plate
Retardation of 147 nm, the
interference colour is a first order
white
Mica Plate
Wedge shaped and produces a
range of retardations
Quartz sWedge
the overall total retardation is less than
that exhibited by the mineral prior to the accessory plate being inserted.
negative elongation
the total
overall retardation is greater than that
exhibited prior to the accessory plate
being inserted
- POSITIVE ELONGATION,
Minerals which display moderate to strong
birefringence may display a change in
relief as the stage is rotated, in plane light.
Relief
coloured anisotropic minerals display a
change in colour
pleochroism or diachroism
form when the vibration
directions in the interference figure
parallel the vibration directions of the
polars. These are areas of extinction
Isogyres
breaking up of the white light
Dispersion
Plane-Polarized (PPL) Properties
Color
- Pleochroism
- Habit
- Cleavage and Fracture
- Relief
- Index of Refraction
Cross-Polarized (XPL) Properties
Birefrringence
- Extinction
- Sign of Elongation
- Twinning and Zoning
This property is present when areas with differing extinction orientations within the same mineral grain have planar contacts.
Twinning
polarizing transmitted-light microscope,
commonly known as
petrographic
microscope
typical bulb used has a tungsten filament, which gives the field view a yellowish tint.
The Light Source
used to reduce the area of
light entering the thin section and should be in focus at the same position asthe thin section: it should be opened until it just disappears
field diaphragm
closed to increase resolution, it can be
seen when the Bertrand’s lens is inserted
aperture diaphragm
serves to direct a cone of light on the thin section and give optimum resolution for the objectives used
small circular lens (the condenser) is
attached to a swivel bar, so that it can be inserted into the optical train when required
Condenser and Convergent Lens
marked in degree units and a side vernier enables angles of rotation to be accurately measured
Stage
power of magnification inscribed on each
lens (e.g. x5, x30). An objective of very high
power (e.g. x100) usually requires
immersion oil between the objective lens
and the thin section
Objectives
used to examine interference figures. When
it is inserted into the upper microscope tube an
interference figure can be produced which fills the field
of view, provided that the convergent lens (condenser)
is also inserted into the optical path train
The Bertrand Lens
The slot is oriented so that accessory
plates are inserted at 45o to the cross wires. In some
microscopes the slot may be rotatable
The Accessory Slot
what is the grit called
carborundum grit
standard thickness
30 microns
30 microns
Buffing
> 66 wt. %
Felsic
52 – 66 wt. % SILICA
Intermediate
45 – 52 wt. % silica
Mafic
silica content
< 45 wt. %
Ultramafic
usually occur from the rapid
crystallization of lava extrusive
rocks cool very quickly, therefore their
minerals form fine crystals which
cannot be seen and distinguished by
the naked eye
Aphanitic
type of texture id
formed when magma cools and
some minerals increase in size
extensively. The sizes may range from
some centimeters to quite a number
of meters
Pegmatitic
plutonic igneous rocks, which
underwent slow crystallization
underneath the surface of the earth
Phaneritic
can also form
when magma is crystallized under a
volcano but eruption occurs before
the crystallization is complete.
porphyritic texture
low silica and gas contents make
them very fluid; i.e., they have a low
viscosity, or resistance to flow
Classification of Ultramafic Intrusive
Rocks
Classification of Pyroclastic Rocks
Ultramafic Rocks
intrusive
ultramafic rocks,
peridotite
extrusive ultramafic rocks.
komatiite
Rocks composed mostly of pyroxene,
calcium-rich plagioclase, and minor
amounts of olivine
Mafic Rocks
Rocks composed mostly of hornblende
and intermediate plagioclase feldspars
produced primarily in convergent plate boundaries in which an oceanic plate is subducting beneath either another oceanic plate a continental plate
Intermediate Rocks
similar to pumice but usually made of iron rich minerals found in basalt lava
cinders (scoria)
mafic crystals of felsic
intermediate
mafic
ultramafic
1-15%
16-45%
46-85%
>85%
occurs between
diagenesis and melting
Metamorphism
rock or metamorphic formation
which has arrived at a chemical
equilibrium through metamorphism at
constant temperature and pressure
conditions, the mineral composition is
controlled only by the chemical
composition
metamorphic facies
substantial chemical change
accompanies metamorphism
involves the infiltration of
fluids and/or the diffusion of material
through the fluid and solid phases
chemical alteration takes place as a
result of these fluids
Metasomatism
when
the T-P increases on a body of rock
Prograde metamorphism
T-P fall due to erosion of overlying rock or due to tectonic uplift
Retrograde metamorphism
Pressure increases with depth due to the weight of the overlying bedrocks
lithostatic pressure
orce acting
equally from all directions, it is a type of
stress called hydrostatic stress, or uniform
stress.
Pressure
rocks undergo metamorphic
reactions due to heating (little or no
pressure change)
when a hot igneous intrusion
(magma) comes into contact with
cold country rock, it creates a
metamorphic aureole / contact
aureole or baked zone.
produces hornfels, a nonfoliated
metamorphic rock
Contact Metamorphism
Rock in the deep portions of faults
undergoes dynamic
metamorphism and creates a fine grained metamorphic rock called
mylonite
referred to as shock
quartz
coesite or stishovite
Started out originally with clay
minerals and as a result of
metamorphism, alumna rich
minerals form
Pelitic
The clay minerals have
recrystallized into tiny micas which
reflect a glossy luster
Phyllite
The rock developed a near planar
foliation caused by the preferred
orientation of sheet silicates.
However, quartz and feldspar
grains show no preferred
orientation
Schist
irregular planar foliation
schistosity
When non-mica minerals (quartz,
feldspars, kyanite, garnet,
staurolite, and sillimanite) occur
with a grain size greater than the
rest of the rock, they are called
pophyroblasts
dark colored minerals tend
to become segregated in distinct
bands through the rock, giving
the rock
gneissic banding
e highest grades of
metamorphism, all of the hydrous
minerals and sheet silicates
become unstable and thus there
are few minerals present that
would show this
granulite
the temperature reaches the
solidus temperature, the rock may
begin to melt and start to comingle with the solids. Usually
these solids are felsic with the
mafic material remaining
metamorphic
Migmatites
Usually poorly foliated and form at
intermediate to high grades of
metamorphism of basaltic or
gabbroic protoliths
Amphibolite
Very fine- grained rocks that
usually form as a result from
magma intruding into fine
grained igneous rocks or shales.
- The magma causes a type of
metamorphism called
contact metamorphism.
Hornfels
Mineral assemblages form from
fine-grained unstable starting materials
such as glassy volcanic rocks, pyroclastics
and greywackes. Diagnostic minerals may
also occur in veins cutting largely
unrecrystallized rocks
Zeolite Facies and Prehnite-Pumpellyite
Facies
what are the Intermediate Pressure Facies
Zeolite Facies and Prehnite-Pumpellyite
Facies
Greenschist facies
Amphibolite facie
Granulite facies
heulandite + analcite + Qtz ± clay
minerals
* laumontite + Ab + Qtz ± Chl
* prehnite + pumpellyite + Chl + Ab
+ Qtz
* pumpellyite + Chl + Ep + Ab + Qtz
* pumpellyite + Ep + stilpnomelane
+ Musc + Ab + Qtz
Metavolcanics and greywackes
Musc + Chl + Ab + Qtz
(indistinguishable from
greenschist facies)
Metapelitic rocks
Chl + Ab + Ep ± actinolite, Qtz
* Metagreywackes
* Ab + Qtz + Ep + Musc ±
stilpnomelane
* Metapelites
* Musc + Chl + Ab + Qtz
* chloritoid + Chl + Musc + Qtz ±
paragonite Bt + Musc + Chl + Ab +
Qtz + Mn-rich garnet
Metabasic rocks (Greenschist facies)
- Dolomite + Qtz
Siliceous dolomites (Greenschist facies)
Hbl + Pl ± Ep, garnet,
cummingtonite, diopside, Bt
Metabasic rocks (Amphibolite facies)
Musc + Bt + Qtz + Pl ± garnet,
staurolite, kyanite/sillimanite
* Siliceous dolomites
* dolomite + calcite + tremolite ±
talc (lower amph. f.)
* dolomite + calcite + diopside
and/or Fo (upper amph. f.)
Metapelitic rocks (Amphibolite facies)
Forms under conditions of P(H2O) <Ptotal. The presence of orthopyroxene in metabasic rocks is diagnostic of this and the pyroxene hornfels facies
Granulite facies
Opx + Cpx + Hbl + Pl ± Bt
* Opx + Cpx + Pl ± Qtz
* Cpx + Pl + garnet ± Opx (higher P)
* Metapelitic rocks
* garnet + cordierite + sillimanite +
K-feldspar + Qtz ± Bt
* sapphirine + Opx + K-feldspar +
Qtz ± osumilite (very high T)
Metabasic rocks (Granulite facies)
what are the High Pressure Facies
Blueschist Facies.
Eclogite Facies
Known also as the glaucophane-lawsonite schist facies; these occur along Mesozoic and Tertiary orogenic belts such as the circum-Pacific belts and the Alpine-Himalayan chain. In high pressure rocks,
mica is phengite rather than muscovite.
Blueschist Facies
glaucophane + Law
+ Chl ±
phengite/paragonite, omphacite
* Metagreywackes
* Qtz + jadeite + lawsonite ±
phengite, glaucophane, Chl
Metabasic rocks (Blueschist Facies
)
phengite + paragonite +
carpholite + Chl + Qtz
Metapelites (Blueschist Facies)
Aragonite
Carbonate rocks (Blueschist Facies)
Eclogitessensustricto are metabasic rocks,
occurring in a variety of associations, e.g.
as enclaves or tectonically-incorporated
blocks in blueschists or medium to high
grade gneisses, or as nodules brought up
in kimberlite pipes. In certain regions, rocks
preserve (albeit imperfectly) distinctive
high-pressure assemblages. Plagioclase is
entirely absent
Eclogite Facies
omphacite + garnet ± kyanite,
Qtz, Hbl, zoisite
Metabasic rocks (eclogite facies)
Qtz + phengite +
jadeite/omphacite + garnet
Meta-granodiorite (eclogite facies)
phengite + garnet + kyanite +
chloritoid (Mg-rich) + Qtz
* phengite + kyanite + talc + Qtz ±
jadeite
Metapelites (eclogite facies)
what are the Low Pressure Facies
Albite-Epidote Hornfels Facies
Hornblende Hornfels Facies
Pyroxene Hornfels Facies
Sanidinite Facies
Likely to be recognized only in the
outermost parts of thermal aureoles in
country rocks originally of very low
metamorphic grade. This is the lowpressure equivalent of the greenschist
facies, and the assemblages are very
similar.
Albite-Epidote Hornfels Facies
Ab + Ep + actinolite + Chl + Qtz
* Metapelites
* Musc + Bt + Chl + Qtz
Metabasic rocks (Albite-Epidote Hornfels Facies)
Low pressure equivalent of the
amphibolites facies. The assemblages
described below can also be found in
regionally metamorphosed rocks
belonging to the low pressure facies series
Hornblende Hornfels Facies
Hbl + Pl ± diopside,
anthophyllite/cummingtonite, Qtz
Metabasic rocks
Hornblende Hornfels Facies
Musc + Bt + andalusite + cordierite
+ Qtz + Pl
Metapelites
Hornblende Hornfels Facies
cordierite + anthophyllite + Bt + Pl
+ Qtz
K2O-poor sediments or metavolcanics
Hornblende Hornfels Facies
same as amphibolite facies
Siliceous dolomites
Hornblende Hornfels Facies
Developed in the inner parts of high
temperature thermal aureoles, such as
those around large basic bodies.
Assemblages similar to granulite facies,
but can be developed at P(H2O) = Ptotal
Hornblende is not stable.
Pyroxene Hornfels Facies
- Opx + Cpx + Pl ± Ol or Qtz
Metabasic rocks
Pyroxene Hornfels Facies
- cordierite + Qtz + sillimanite + Kfeldspar (orthoclase) ± Bt
- cordierite + Opx + Pl ± garnet, Sp
Metapelites
Pyroxene Hornfels Facies
calcite + Fo ± diopside, periclase
* diopside + grossularite +
wollastonite ± vesuvianite
Calcareous rocks
Pyroxene Hornfels Facies
Rarely found, as the extremely high
temperatures required are only achieved
at direct contacts with flowing basic
magma, or in completely-immersed
xenoliths
Sanidinite Facies
cordierite + mullite + sanidine +
tridymite (often inverted to Qtz) +
glass
Metapelitic rocks
Sanidinite Facies
- wollastonite + An + diopside
- monticellite + melilite ± calcite,
diopside - alsotilleyite, spurrite, merwinite,
larnite and other rare Ca- or CaMg silicate
Calcareous rocks
Sanidinite Facies
showed
that metamorphism of tuffs in NZ
accompanied by substantial
chemical changes due to circulating
fluids, and that these fluids played an
important role in the metamorphic
minerals that were stable
Boles and Coombs
Mafic Assemblages at Low Grades
Zeolite and prehnite-pumpellyite
facies
Mafic Assemblages of the Medium P/T
Series
Greenschist, Amphibolite, and
Granulite Facies
constitute the most
common facies series of regional
metamorphism
greenschist, amphibolites and
granulite facies
classical Barrovian series of pelitic
zones and the lower-pressure BuchanAbukuma series are variations on this
trend
Mafic Assemblages of the Medium P/T
Series
Metamorphism of mafic rocks first evident
greenschist facies, which correlates
with the chlorite and biotite zones of
associated pelitic rock
impart
the green color form which the mafic
rocks and facies get their name
Chlorite, actinolite, and epidote
Amphibolite facies transition
involves two major mineralogical changes
1. Albite→ oligoclase
2. Actinolite→ hornblende(amphibole
accepts increasing aluminum and
alkalis at higher T)
Greenschist
Mafic Assemblages of the Low P/T
Series
Albite-Epidote Hornfels,
Hornblende Hornfels, Pyroxene
Hornfels, and Sanidinite Facies
Albite-epidote hornfels facies correlates
with the greenschist facies into which it
grades with increasing pressure
Hornblende hornfels facies correlates with
the amphibolite facies, and the pyroxene
hornfels and sanidinite facies correlate
with the granulite facies
Mafic Assemblages of the High P/T
Series
The association of glaucophane +
lawsonite is diagnostic
Blueschist and Eclogite Facies
characterized in
metabasites by the presence of a sodic
blue amphibole stable only at high
pressures (notably glaucophane, but
some solution of crosstie or riebeckite is
possible)
blueschist facies
stable to
lower pressures, and may extend into
transitional zones
Crossite
breaks down at high pressure by
reaction to jadeitic pyroxene + quartz:
Albite
Unstable minerals
pyroxenes,
olivines, amphiboles, some plagioclase
feldspars
Stable minerals
quartz, K-feldspar,
Na- feldspar, muscovite, clay minerals,
some ‘heavy minerals’
(transported to the
site of deposition
allogenic
example: Framework grains and
matrix
precipitated at the site of
deposition
authigenic
cements
Preferential orientation of particles in a
sediment or tendency of a rock to break
in specific directions
Fabric
cemented by minerals
precipitated in pore spaces breccia and conglomerate
✓ Silica (quartz)
✓ Carbonate (calcite)
✓ Ferruginous (Fe-oxides)
Common cements
calcite,
hematite, quartz, and clay
Common association on glacial
till and debris flow deposits
Paraconglomerate
Flat-pebble conglomerates
formed by mud rip-ups
Intraformational (within basin)
More likely to be petromictic
Extraformational (outside basin)
Three components of a rock:
Grains: > 0.03 mm (about φ5 = 31.3 mm;
i.e. coarse silt and coarser).
- Matrix: < 0.03 mm (finer than coarse silt);
- Cement: not considered in this
classification
high textural
maturity, grain-supported fabric,
grains held together by chemically
precipitated cement.
< 15% matrix - arenites
15%-75% matrix
wackes: dirty, low
textural maturity, largely matrixsupported fabric
The degree of mineralogical maturity can be determined by looking at the types of grains present
contains no feldspar (feldspar easily
weathers to clay)
Presence of fresh, large, angular feldspar
fragments in a sandstone imply
a high relief source area (rapid
erosion, transport, burial, with little
weathering effect OR ;
b. a very arid or extremely cold climate
(retards chemical weathering)
Small, rounded, highly weathered
feldspars imply:
a. a low relief source area and/or warm,
humid climate (modernintense weathering processe
Absence of feldspars imply
a. intense weathering (destroying
feldspars) OR no feldspars in original
source
rock fragments are
chiefly of shale or slate
Phyllarenite
where the rock fragments
are of limestone
Calcilithite
Feldspar is chiefly K feldspar and
much of this is microcline.
Texture is typically poorly- to wellsorted, with very
typical red or pink,
through the feldspar’s color, but
also through the presence of
finely disseminated hematite.
Arkoses
chiefly of mudrock and
their low grade metamorphic
equivalents and volcanic grains
Lithics
fluvial and deltaic
sandstones
Immature composition implies
high rates of sediment production
followed by short transport
distances
Litharenites
fine-grained matrix, which consists
of an intergrowth of chlorite,
sericite and silt- sized grains of
quartz and feldspar
fine-grained sedimentary
and meta-sedimentary rock types
dominate. Feldspar grains are
chiefly Na plag
Greywackes
oscillatory (microscale) zoning:
volcanic or hypabyssal origin
- progressive (coarse) zoning:
igneous source, undifferentiated
Plagioclase Zoning
are the most abundant of all
lithologies, some 45 - 55% of sed. rxs.
- Main constituents - clays and qtz.
- Clay mineralogy reflects to a greater
extent the
MUDROCKS
calcareous mudrocks
Marls
<4µm; Silt - 4 to 62 µm
Clay -
usu. laminated and fissile.
Shale
used for a more indurated
mudrock
Argillite
Absent when sediments are
bioturbated, presence of much qtz silt
or calcite, flocculation of clays during
sedimentation
Fissility
mainly due to variations in grain size
and/or changes in composition
- Deposited in relatively short periods of
time (hours or days) by turbidity
currents or
- Develops over months or years if there
are annual or seasonal change in
sediment supply or biological
productivity
Lamination
The simplest phyllosilicates result from
bonding one silicate layer to one
octahedral layer. Because of this
arrangement, we call these the 1:1
phyllosilicates
Phyllosilicate Structures
Montmorillonite and beidellite
result from the alteration of
volcanic ash to give bentonite
clay deposits
Montmorillonite Group (Smectites)
Clay Minerals
the most common clay mineral in
sedimentary rocks
. Illite
Montmorillonite Group 2:1
Illite
Chlorite
dominant in low-latitude areas,
particularly off major rivers draining
regions of tropical weathering.
most important 1:1 phyllosilicate
Kaolinite
more common in ocean-floor muds
of higher latitudes.
Illite
related to active mid-ocean
ridge systems and volcanic oceanic
islands
Smectites
25% of all sedimentary rocks
✓ Present from the pre-cambrian
onward
Carbonate Rocks
Pre-cambrian Carbonates –
almost all dolomite
- Tertiary Carbonates – very
little dolomite
Carbonate Requirements
Sunlight – carbonates form in shallow
water within the photic zone (0-60m);
this is related to primary productivity
(phytoplankton)
2. Turbidity – form in clear clastoic free
water. Low turbidity enhances light
penetration and prevents clogging of
filter feeders, abrasion of shells by
quartz
3. Temperature – form in warm water.
Carbonate accumulate requires
water below 20oC with consistent
temperature
4. Stable normal oceanic salinity – 35 ppt
5. Thus, limited to within 30o Noth and
South of equator (tropics and
subtropics
Orthorhombic Crystal
- Hardness of 4
Aragonite
Hexagonal (rhombohedral crystal)
▪ Hardness of 3
been dominant
skeletal material in during the
Paleozoic
Siderite – (FeCO3)
* Magnesite – (MgCO3)
* Rhodochrosite – (MnCO3)
Dolomite – CaMg(CO3)2
– fecal material excreted
by benthic organisms
Peloids
These are exoskeletons or benthic
(bottom-dwelling), mobile and
sessile (esp. attached) organisms
Gastropods (Snails)
* Pelecypods (Clams)
* Echinoderms (Sand dollars,
Starfish)
* Cnidarians (Corals)
microgranular in many thinwalled foraminifera but fibrous in
larger, thicker species, such as
rotaliids, nummulites and orbitolinids.
test wall
FORAMINIFERA
Composed of low or high-Mg calcite,
rarely of aragonite.
- Very diverse in shape but common
forms are circular to subcircular w/
chambers.
(Jurassic-Recent.)
are planktonic algae w/c have lowMg calcite skeleton consisting of a
spherical coccosphere (10-100µm
diameter) composed of numerous
calcareous plates, called coccoliths.
- Coccoliths are chiefly disc-shaped,
commonly w/ a radial arrangement
of crystals.
significant component
of modern deep-water carbonate
oozes, particularly those of lower
latitudes, esp. in Tertiary and
Cretaceous
Coccolithophorids
other term for Coccolithophorids
Chrysophyta
generally < 4 µm
✓ Lime mud is common in both
modern and ancient
✓ Consists of microcrystalline calcite
or aragonite
✓ In the modern, lime mud is derived
from disaggregation of
calcareous green algae which
releases aragonite needles 1-5µm
long
✓ Other possible sources or origin of
micrite
a. Inorganic precipitation
b. Bioerosion where organisms
such as boring sponges and
microbes attack carbonate
grains and substrates
. Mechanical breakdown of
skeletal grains thru waves and
currents.
. Micrite
large crystals of
Lo-Mg calcite that from cement in
limestones
Sparry calcite
photic zone
(generally 0-30 m) is the most productive
site for carbonate sediments, the socalled carbonate factor
year of folks
1959 1962
limestone
formed in situ such as a stromatolite or
reef-rock;
biolithite-
micrite w/
cavities such as birds-eye limestone
dismicrite
general term for fine-grained
siliceous sediments of chemical,
biochemical or biogenic origin.
Chert
for chert nodules occurring in
Cretaceous chalks
Flint
fine-grained siliceous rocks
w/ a texture and fracture similar to
unglazed porcelain; also used for an
opaline claystone composed largely of
opal-C
Porcellanite
Three major groups of organisms that build
their skeletons of silica:
Sponges-very
important contributors of siliceous
spicules to the sea-floor since the
Paleozoic
Radiolarians- marine planktonic protozoans;
Paleozoic to Recent
- skeleton or “tests” of opaline silica
- live in near surface waters and
feed of phytoplankton dominant
sediment in the Equatorial Pacific
beneath the CCD
Diatoms- marine and non-marine;
photosynthesing algae
- live in the surface water -
photosynthetic zone
- since the early Cretaceous
- principal component of marine
phytoplanktons; a.k.a. “grass of
the sea”; base of the food chain
also referred to as
drusy quartz as it commonly
occurs as a pore- filling cement
megaquartz
usually occur in a radiating
arrangement
* forming wedge-shaped, mammillated and spherulitic growth
structures
fibrous variety
w/ crystals varying from a few tens to
hundreds of microns in length
chalcedonic quartz
defined as sediments with > 15-20%
P2O5; a source of fertilizer
Phosphatic Sediments
associated with regions
of relatively high surface water fertility;
accumulate near the edges of the
oxygen minimum depth zone and is
commonly a place where organic rich
sediments like diatom ooze is being
deposited
Phosphorites
deposits of organic
material (mainly from phytoplanktons)
in marine basins and lakes
Sapropels
forms during the accumulation
of plant remains in anaerobic, watersaturated environment, generally in
fresh water swamps and bogs in cool
climates
peat
vascular (land) plant derived
organic compounds altered
by elevated temperature
and burial pressure
Humic coal
Formed from non-vascular
(algal) plant material
Sapropelic coal
sylvinite: mixture of sylvite,
carnallite and halite – fertilizer
potash
metastable; not
preserved in rocks older than miTertiary; readily devitrified and
replaced during weathering and
diagenesis
Volcanic glass
smectite rich clay beds
derived from the alteration of
volcanic ash
Bentonite
hydrous sodium calcium
aluminum silicates; formed from
alteration volcanic glass, usually
cryptocrystalline; often develop when
ash has fallen into alkaline lakes
Zeolites
generally refers to beds thicker than
10 mm
beds:
✓ very thick bed > 1 m thick
✓ thick bed 1-0.3 m
✓ medium bed 0.3-0.1 m
✓ thin bed 0.1-0.01 m (overlap with thick
lamina)
✓ very thin bed < 10 mm (overlap with
medium lamina)
generally refers to beds thinner
than 10 mm
laminae
✓ thick lamina 10-30 mm
✓ medium lamina 3-10 mm
✓ thin (fine) lamina 1-3 mm (e.g.
Devonian Ratner of Sask) very thin
(fine) lamina < 1 mm (deep sea and
deep lake deposits, glacial lake
varves)
(= ichnofossils = lebensspuren): traces of
organism (commonly animal) activities
and behavior (dwelling, feeding,
locomotion, resting), not actual body
fossils.
Trace fossils
MINERAL RESOURCES FROM SEDIMENTS
Banded iron formation (BIF)
* Evaporite deposits (halite, gypsum,
potassium and magnesium)
* Placer deposits (gold, diamond, tin
oxides)
* Bauxite (aluminum; residual of clay
deposits in tropical and subtropical
regions)
* Laterite (iron; residual soil; tropical
weathering)
* Magnetite
* Fossil fuels (oil, natural gas, coal)
groundmass is made up rectangular formed feldspar instead of lath slender lath crystals
orthopyric
phenocrysts in a porphyritic texture are clustered into aggregates called glomerocrysts or crystals clots which indicates crystal fractionation by crystal settling
glomeroporphyritic
phenocrysts contain small grains of other minerals enclosing them indicating that the smaller grains may have crystallized first
poikilitic
variety of poikilitic texture where plag laths are enclosed by pyroxenes or olivine
ophitic
variety of ophitic wherein plag encloses ferromagnesian minerals indicating slower cooling in basaltic rocks
subophitic
also called corona reaction rim and rapakivi displays a secondary mineral formed around another mineral indicating a post magmatic reaction
opacitic
variety of opacitic where there is a secondary rim or corona
kelyphitic
occurs where crystal occupies occupy spaces between at least two larger crystals indicating a later formation
intergranular
denotes that angular spaces between crystals are filled with glass that may be devitrified or altered and small crystals
intersertal
holocrystalline groundmass with lath shaped microlites typically pla are generally oriented irregularly
pilotaxitic
extrusive igneous rock texture wherein the groundmass flow in the direction of lava flow and around inclusions and occurs in alkali rich rocks
trachytic
microscopic variety of trachytic that is visible to the naked eye
trachytoid
also called symplectic is an intergrowth of branching rods of quartz set in a single crystal of plag
myrmekitic
intergrowth of plag feldspar in alkali feldspar host
perthitic
intergrowth of alkali feldspar in plag feldspar host
holocrystalline
mix of glass and crystals but contains more crystals than glass
hypohyaline
contains 100% glass
holohyaline
contains very coarse grains having >30mm in diameter
pegmatitic
displays grains that are generally equant
granular
medium to coarse grained minerals most of which are devoid of crystal faces
granitic
contains equidimensional cryptocrystalline groundmass
felsitic
variety of poikilitic where in inclusions have a complete series of crystal sizes
seriate
loss or decrease in pressure which becomes the driving force of volcanoees to erupt causing the less dense magma material to rise and migrate to areas with less pressure
decompression
lowering of the melting temperature of the mantle due to the presence of fluxes causing earlier melting and production of the magma
flux melting
who devised the way of measuring the relative size or magnitude of volcanic eruptions ?
The Volcano Explositivity Index
Newhall, C. and Self S. in 1982
steam eruptions that occur when water is heated by the country rock without having the need to be in contact with a magmatic body and erupts as a mixture of hot water and steam
phreatic
also called surseyan eruption
is an explosive eruption produced when a magmatic body comes in contact with water causing rapid quenching and expansion of materials violently bursting into steam and volumes of ash
phreatomagmatic
effusive eruptions that produce large volumes of very hot thin runny lava that extrudes from fissures
icelandic
effusive eruptions similar to icelandic eruptions that originates from vents of volcanoes
hawaiian
explosive euptions that shoot thicker lava along with a burst of steam gas and ash that spatters molten lava
strombolian
series of discrete loud eruptions in throat clearing canon like explosions that shoor high velocity blocks and bombs
vulcanian
also called nuee ardente eruptions occur when large amount of tephra gas and lava are erupted laterally from the crated producing glowing avalanches
pelean
colossal explosive eruptions that involves very viscous magma and produce very large volumes of ash and tephra that can cover a very wide area
plinian
composed mostly of loose ejected ash and some lava appearing relatively symmetrical and steeply built with large deep craters with most being produced by a single eruptive event
pyroclastic cone
pyroclastic cones composed predominantly of vesicular basaltic material
scoria cone
pyroclastic cones with various compositions
cinder cone
volcanoes with an eruptive history that reached VE 8 or stronger
Supervolcano (yellowstone caldera)
give examples of extinct volcano, dormant volcano, inactive volcano and potentially active volcano
mt. chimborazo, ecuador
mt. kilimanjaro tanzania
alligator lake tadlac lake laguna
mt. san cristobal laguna
short detached vesicle free proximal lava that are often produced by viscous lava such as andesitic and rhyolitic lava
block lava
a fractured surface texture formed when bombs cool
breadcrust texture
black glassy streamlined particles that formed as lava droplets that quenched in flight
pele’s tears
golden acicular glassy strands that formed as lava droplets were propelled through the air being partially stretched into shape
pele’s hair
usually associated with phreatic and pheratomagmatic eruptions and identified to have a pinch and swelling beds with moderate sorting of moderately rounded clasts
pyroclastic surge
generally hot flows made up of a mixture of pyroclastic materials and hot gases that can travel at rapid speeds
pyroclastic density currents
also known as cognate clasts are derived directly from magma involved in the volcanic activity
juvenile clasts
rock inclusions from the vent wall or brought from the surface by lava or pyroclastic walls
accidental clasts
fragmentation through explosive ejection and aerial dispersal of pyroclasts of rock and magma from a volcanic vent
autoclastic process
fragmentation brought by the weathering and disintegration of volcanic rocks
epiclastic process
clasts within the mass flow behaving independently in moving interstitital fluids
traction transport
a hot mixture of volcanic debris and tephra that is saturated with water that occurs directly related to an on going eruption
syn eruption lahar
also known as large igneous provinces or LIPS are products of massive outpourings of low viscosity basaltic lava that envelop hundreds of thousands of square kilometers
flood basalt
airborne blobs of liquid lava emitted by lava fountaining
spatter
also called welded spatter are spatters that solidified at the base of the lava fountain
agglutinate deposits
cones produced when welded spatters accumulate around a central vent that can typically grow less than 20m in height
spatter cone
linear ridges formed when lave fountains erupt via fissures
spatter ramparts
smaller tuff rings
tuff cone
glassy volcanic debris and scoria develop die to the explosive eruption of basalt in a water
tuff ring
when was PHIVOLCS established
September 17, 1984
