minerals Flashcards
is a manganoan variety of muscovite that was originally described in 1865 by J.F.H. Breithaupt who also named the mineral. The name alurgite is from the Greek word “halourges” meaning (“genuine purple dye from the sea”) in allusion to its typical reddish-purple color. Alurgite is a reddish-purple variety of muscovite that gets its color from the presence of Mn in its chemical formula. W. T. Schaller (1959) Placed alurgite as an intermediate between leucophyllite (now a synonym of aluminoceladonite) and muscovite.
Alurgite - K2(Mn, Mg,Al)4-5(Al,Si)8O20(OH)4
a common regional metamorphic mineral which forms under low pressure and low to high temperatures. The minerals kyanite and sillimanite are polymorphs of andalusite, each occurring under different temperature-pressure regimes and are therefore rarely found together in the same rock. All three polymorphs can be used as index minerals in metamorphic rocks. They all develop in alumina-rich pelites under different conditions of temperature and pressure. Andalusite form al low pressures (<1.5 Kb) and low moderate temperature in thermal aureoles and regional metamorphism of Buchan type (high T and low P). At higher temperature its invert in sillimanite.
Andalusite
commonly contains dark inclusions of carbon or clay which form a checker-board pattern when shown in cross-section, while viridine, or manganandalusite, is a Mn-rich variety of andalusite, with deep green colors.
variety chiastolite
a mineral belonging to the serpentine group of minerals. forms during low-grade metamorphism of olivine-rich rocks (peridotite and other ultrabasic rocks, gabbros, lamprophyres, etc.); is a major component in serpentinites. Antigorite can be accompanied by lizardite which can form the major component in pseudomorphs after orthopyroxene.
Antigorite
common component of some metamorphic and metasomatic rocks. Its name comes from the Latin word for clove and is an allusion to its typical and distinct clove-brown color.is the product of metamorphism of magnesium-rich rocks, especially ultrabasic igneous rocks and impure dolomitic shales. It also forms as a retrograde product rimming relict orthopyroxenes and olivine, and as an accessory mineral in cordierite-bearing gneisses and schists. also occurs as a retrograde metamorphic mineral derived from ultramafic rocks along with serpentinite.is formed by the breakdown of talc in ultramafic rocks in the presence of water and carbon dioxide as a prograde metamorphic reaction. The partial pressure of carbon dioxide (XCO2) in aqueous solution favors production of anthophyllite. indicative of at least greenschist facies metamorphism in the presence of carbon dioxide bearing metamorphic fluids.
Anthophyllite
occurs in contact and medium to high grade metamorphic rocks in association with garnet, cordierite, anthophyllite, cummingtonite, sapphirine, sillimanite,kyanite, quartz, staurolite and biotite. Gedrite was first described for an occurrence in Gèdres, Héas Valley, Francein 1836.
Gedrite
a solid solution between the end members Phlogopite KMg3AlSi3O10(OH)2 and Annite KFe3AlSi3O10(OH)2, although pure Annite does not occur in nature. In addition, small amounts of Na, Rb, Cs, and Ba may substitute for K, and like in other minerals, F can substitute for OH and increase the stability of Biotite to higher temperatures and pressures. a sheet silicate; iron, magnesium, aluminium, silicon, oxygen, and hydrogen form sheets that are weakly bound together by potassium ions. It is sometimes called “iron mica” because it is more iron-rich than phlogopite. It is also sometimes called “black mica” as opposed to “white mica” (muscovite). the most ubiquitous ferromagnesian mineral occurring in most igneous and metamorphic rocks. Nearly pure phlogopite is found in hydrous ultrabasic rocks like kimberlite, and is also found in metamorphosed dolomites. ore Fe-rich compositions is common in dacitic, rhyolitic, and trachytic volcanic rocks, granitic plutonic rocks, and a wide variety of metamorphic rocks.
Biotite
Form: pseudoexagonal basal section (001), rectangular (110) section.
* Relief: Moderate.
* Color: brown to black.
* pleochroism: yellow to brown to green colors.
* Interference colors: third-order colors.
* cleavage: perfect {001} micaceous cleavage.
* extinction: Bird’s eye extinction, or bird’s eye maple, is a specific type of extinction exhibited by minerals of the mica group under cross polarized light of the petrographic microscope. It gives the mineral a pebbly appearance as it passes into extinction
Biotite
A fibrous variety of Brucite is called
nemalite
has a layer structure with hydroxyl (OH-) groups in hexagonal close packing. Each Mg is octahedrally coordinated to six O– groups and these octahedra share edges to form the layers. Brucite is a common alteration product of periclase, which is commonly formed in metamorphosed dolomites. common low-temperature hydrothermal mineral in metamorphosed limestones and chlorite schists and is often found serpentinized dunites.
Brucite - Mg(OH)2
Form: Is typically in flattened tabular crystals with rare rhombohedral terminations. Also found in lamellar and fibrous aggregates and as foliated masses.
* Cleavage: Perfect in one direction, basal.
* Relief: Moderate.
* Birefringence: High.
Brucite - Mg(OH)2
Aragonite will change to calcite at what temperature
380-470 °C
Trigonal carbonate have a structure similar to
halite
low pressure polymorph and is the only truly stable form under surface condition. Color: Colourless
* Form: In thin section usually show fine to coarse anhedral aggregate
* Cleavage: Perfect rhombohedral cleavage intersect at about 75°
* Interference colors: V orders interference colors
* Relief: Calcite is characterized by change in relief during a 360°rotation of the stage; the crystals is said to “twinkle” during rotation.
Calcite
tin oxide mineral and it is the most important source of tin, and most of the world’s supply of tin is obtained by mining cassiterite. Small amounts of primary cassiterite are found in igneous and metamorphic rocks throughout the world. It is also a residual mineral found in soils and sediments. more resistant to weathering than many other minerals, and that causes it to be concentrated in stream and shoreline sediments an be found in hydrothermal veins and pegmatites associated with granite intrusions. May also precipitate from volcanic gas, as shown by experiments of Africano et al. (2002), in which it deposits in the 550-240°C range.
Cassiterite - SnO2
Form: Usually as fibrous, botryoidal crusts or concretionary masses. Granular, coarse to fine.
* Twinning: Both contact and penetration twins.
* Colour: Black, yellow, brown, red or white.
* Relief: Very High.
* Interference colours: Very High.
Cassiterite - SnO2
“the lilac miracle of Siberia” and It is considered “the main mineralogical discovery of the second half of the 20th century”. Charoite was discovered in 1949 and confirmed as a new mineral species in 1977. According to the discoverers of the mineral, the name originates from the Chara River, situated close to the southem border of the Murun complex. An “unofficial” hypothesis suggests the Russian word “charovat” (to charm) as a possible origin for the name. It has been found at only one locality in at the broad contact aureole of the Early Cretaceous Malyy Murun syenite massif, northwestern Aldan Shield of the Siberian Craton
Charoite - K5Ca8(Si6O15)2(Si2O7)Si4O9(OH)*3(H2O)
- Form: Massive to Fibrous.
- Color: Colorless.
- Pleochroism: Weak (from rose to colorless).
- Relief: Low.
- Interference colors: Low (I order white-gray).
Charoite - K5Ca8(Si6O15)2(Si2O7)Si4O9(OH)*3(H2O)
ostly monoclinic (also triclinic or orthorhombic) micaceous phyllosilicate minerals with a structure consisting of T-O-T layers with two layers having their silicate tetrahedral apices pointing towards each other, separated by an interlayer that may be simple octahedrally coordinated cations or which may be a brucite-like layer of two sheets of closely packed OH groups with the interstices between sheets providing the octahedral cordination site. linochlore: (Mg5Al)(AlSi3)O10(OH)8
♦ Chamosite: (Fe5Al)(AlSi3)O10(OH)8
♦ Nimite: (Ni5Al)(AlSi3)O10(OH)8
♦ Pennantite: (Mn,Al)6(Si,Al)4O10(OH)8 an important constituent of many contact and regional metamorphic rocks of low to medium grade, usually with temperatures of to 400°C and pressures up to a few Kb. It also found in amygdules, fractures in altered volcanic rocks, hydrothermal vein deposits and soils often found with biotite, garnet, staurolite, andalusite, muscovite, chloritoid, and cordierite in pelitic rocks. In mafic rocks, it occurs with talc, serpentine, actinolite, hornblende, epidote, and garnet. It can also be found with feldspars, quartz, calcite, dolomite, olivine, plagioclase, rutile, ilmenite, titanite, magnetite, chromite, sulfides, zircon, and zeolites. forms by the alteration of mafic minerals such as pyroxenes, amphiboles, biotite, staurolite, cordierite, garnet, and chloritoid. Chlorite can also occur as a result of hydrothermal alteration of any rock type, where recrystallization of clay minerals or alteration of mafic minerals produce
Chlorite - (Mg,Fe2+,Fe3+,Mn,Al)12(Si,Al)8O2016
- Color: Colourless ore green, pale green
- Habit: Tabular crystals with pseudo-hexagonal shape
- Cleavage: (001) perfect
- Interference colors: Very weak (brown, deep green, gray), usually with anomalous deep berlin blue
- Relief: Low to moderate
Chlorite - (Mg,Fe2+,Fe3+,Mn,Al)12(Si,Al)8O2016
formely known as octahedrite
polymorph of titanium dioxide
anatase
formed by weathering pf titanite
anatase
weathered anatase becomes
rutile
crystal system of anatase
tetragonal
crystal system of brookite
orthorhombic
brookite is widespread in mineral veins in the
Alps
rednor glowing
appears a pale golden needlelike crystals inside quartz latticelike
starlike sprays
minor constituents of granites and schists and gneisses
rutile
crystal system of rutile
tetragonal
medium grade metamorphic rocks metamorphosed shales mknoclinic parallel extinction pleochroism positive optic sign 2V = 82- 90 inclusions with quartz
staurolite
accessory mineral more siliceous igneous rocks lokes granites granodiorites and syenites dates to be obtained on the original tock prior to metamorphism protolith
reddish colored crystals uniaxial positive high birefringence lots of ponks occurs as small crystals with relief higher than polarized light without analyzer
zircon
plutonic igneous tocks like granites seen as small wedge shaped relief sinilar to that of zircon found in small crystals elongated diamond shape
sphene titanite
epidote group 10 fold
epidote clinozoisite zoisite
Fe rich variety of epidote
clinozoisite
clinozoisite and epidote
zoisite
nonoclinic
orthorhombic
optically negative 2V 64-90 pistachio green in color anomalous blue extinction
epidote
negative with a 2V of 14-90 no pleiochroism
clinozoisite
show parallel extinction relative to faces parlel to the crystallographic axes
zoisite
occur as alteration products of plagioclase and as veins in granitic rocks
clinozoisite and epidote
under cyclosilicates
beryl
tourmaline cordierite
hexagonal if pink it is morganite high relief than quartz optic sign and length fast charac found in aluminous mica schisys confused with apatite
beryl
orthorhombic cyclical twinning show albite twinning distinguished from quartz by its biaxial charac constituent aluminous metamorphic rocks assoc andalusite sillimabite feldspar
cordierite
hexagonal with a rounded triangular cross section perpendicular to the c axis common mineral in pegmatites assic with quartz and alkali feldspar found in metasomatized precipitated feom boron and solica uniaxial negative optical chrac extinction parallel
tourmaline
orthorhombic pyrixenes opx
enstatite-ferrosilite
monoclinic pyroxenes cox
diopside hedenbergite diopside-ferrohedenbergite
closely related to the dipsiode hedenbergite series with add of al minor na substitution
augite
a monoclinic puroxene compo similar to the opx with more ca substituting for fe and mg
pigeonite
sodic pyroxenes
jadeite and aegerine
mg rich opx and fe rich is
hypersthene
ferrosilite
present between the diopside hedenbergite series and px series
solid immiscibility
only stable at higher temperature and inverts to opx found in volcanic and shallow intrusive igneous rocks or as exsolution lamellae in a host augite or opx
pigeonite
inclined extinction
cpx
found in plutonic and volcanic igneous hogh grade meta igneous rocks like gneisses and granulites 90 cleavage anges distinguish from opx by onclined extinction higher mac birefringence than opx optically positive with a 2V of about 60 degrees higj relief no pleiochroism
augite
found both plutonic and volcanic igneous rocks in meta igneous rocks distinguish from augite by lower intercerence lack of inclined extinction optically positive 2V of 60-90
hypersthene
found in volcnaic igneous rocks occur as exsolution lamellae ib augites distinguish from augute by its lower 2V of 0 to 30 distinguish from hypersthen lack of pleiylower 2V and inclined extinction
pigeonite
also called acmite sodic pyroxenes found i alkalic ifenous rocks assoc eith soduc amphiboles alkali fels and nepheline found in sodic volcanic rocks like peralkaline rhyolites distinguish from cpz by low wxtinction angle cause augite have 35-48 optically negative with a 2V of 60-70 and
aegerine
higher 2V can be pos or neg distinguish from pleochroic sodic nearly 90 degrees pyroxene cleavage angle
aegerine augite
sodium aluminum pyroxene that is charac its presence in metamoprphic rocks formed at relatively high pressure lower refractive index its monoclinic extinction angle of 33-40 has lwoer birefringence than augite and aegerine
jadeite
solid solution between anthophyllite and grunerite
cummingtonite-grunerite
hornblende series
tremolite-ferroactinolite
sodic amphiboles
glaucophane
riebeckite
arvedsonite
low grade metamorphic those with high Ca concentration fibrous habit in thin section it is distinguished from wollastonite ans diopside by its anphibole cleavage no pleiochroism shows high relief inclined extinction optically negative 2V of about 85
tremolite
low grade metamorphic green in hand specimen elongated habit yellow to green pleiochroism has hig hrelief optically negative a 2V of 60 to 85
actinolite
found in andesites dacites and rhyolites metamorphosed to intermediate grades kf regional metamorphism found in ultrabasic rocks high relief optic sign and 2V angle cover a wide range and not very useful in the distinction of hornblende
hornblende
results from oxidation during crystallization of basalts dark reaction rim that consists of opaque oxide
basaltic hornblende oxy hornblende
low grade metamorpphic rocks high Ca concentration hand specimen white color fibrous havit and distinguished from wollastonite and diopside by its amphibole cleavage cleae to no pleiochroism high relief inclined extinction optically negative with a 2V of about 85
tremolite
dows not occur in igneous rocks but constituent of metamorphic rocks orthorhombic amphibole parallel exctinction relative to the cleavage
anthophyllite
metamorphosed ifneous rocks series occur hornblende found in siliceous volcanic tocks optically positive while grunerite is negative
cummintonite-grunerite
common mineral in blueschist facies from low temperature high pressure metamorphism found in alkali granites distinguished distinguished from other amphiboles by its blue lavender pleiochroism length slow and riebeckite length fast
glaucophane-riebeckite
peralkaline volcanic rocks occurs with sodic pyroxene aegerine yellow grwen pleiochroism distinfuish it drom the other amphiboles
arfvedsonite
serpentine group
antigorite not similar bending sheets and lizardite usually massive and fine grained chrisotile continuous
found as an alteraation peodict of mg rick silicates like pyroxene and olivine foundpsedomorphed after olivines and lyroxenes altered basic and ultrabasic igneous rocks
serpentine group
micaceous structure rich in Mg low grade metamorphic rocks mg bearing biaxial negative with a 2V of 0-30 muscovite has higher birefringence and higher 2V
talc
divided into dioctahedral and trioctahedral
what are the white micas that relresents the dioctahedral
and the black or brown mica represents the trioctahedral
and rich pink micas
mica group
muscovite paragonite margarite
biotite snd clintonite(xanthophyllite)
lithium lepidolite, k
al rich medium grade metamorphic al rich schists and contributed to the schistose foliation found in siliceous al rich plutonic igneous rocks found in assoc alkali felds high birefringence biaxial negativr with a 2V between 28 and 50 birds ee extinction exhibited
muscovite
how much oercent of kuscoite in k rich and na rich
65%-100%
89%-100%
solid solition between end members phlogopite and anniye higher temp and pressure and pure phlogopite is found in hydrous ultrabasic rocks like kimebrlite parallel to the schistose foliation biaxial negative with a low 2V of 0-25
biotite
consists of phlogopite T O T layers sandwiching brucite like octahedral layer low grade metamorphic to ks an alteration product of pyroxenes recognized by its green color kicaceous habit assoc with other actinolite and epidote low relief and low birefringe midnight blue to black distinguished from biotite by its lower relief and anonaloud interference color
chlorite group
solution that has abundant free H+ ions
acid
produced in raineater by readtion of the water with carbon dioxide gas in the atmosphere
caebonic acid
most abundant contributors to clastic sediment and soil
clay minerals and quartz
main constituents of mudeocks and 40% of the minerals in sed rocks used in ceramics industry
clay
based kn kaolinite show a TVO dtructure octahedral dimilar to the hibbsite structure bonding week since vanderwaals other similar structures anauxite dickite nacrite formed by waethering or hydrothermal alteration of aluminosilicate minerals rocks imrich in felds weather to kaolinite
kandite
is alos a kandite clay similar to kaolinite tho it has water molecules
kaolinite bec it does jot wbsorb water
halloysite
has T O T amounts of mg and fe substituting into the octahedral laters both diocathedral and trioctahedral ability for H2O nilecules to be absorbed between T O T dheets ovlume of miberlas ot increase when thry come invfontact with water these are expanding clays
smectite
most common smectite and main constituent of bentonite weathering of volcanic ash exaond by several times original volume makes it useful as a drilling mud plug leaks
montromorillinite
members of the smectite group
beidellite hectorite nontronite sauconite saponite
similar to muscovite deficient in alkalies with less Al substitution for Si non exoanding clays formed from weathering of ak and Al rich tockes ubder high Zpzh conditiond form by alteration kf minerlas like muscovite and feldsppar ancient mudrocks and shales
illites
change from one type to another theough stacking sequence montromillite layers can alternate with illite layers in sn ordered way
mized layer clay
disintegrating agent that is added to the water to keep particles from adhering to one another
calgon
polymorphs of SiO2
stishovitcoesite
low quartz
high quartz
kaetite
low tridymite
high tridymite
low cristobalite
high cristobalite
tetragonal
monoclinic
hexagonal
hexagonal
tetragonal
monoclinc ornorthorhombjc
hexagonal
tetragonal
isometric
high pressure forms of SiO2 higher densitites and refractive indices than the other polymorphs
stishovite and coesite
the only polymorph where the Si occurs in 6 fold due to high pressure under which mineral forms
stishovite
hezagonal microcrystalline masses occurs in siliceous ignesous rocks such as volcanic rhyolite and pkutonic granitic rocks common in metamorphic rocks resistant to chemical weathering uniaxial positive low relief and low birefringenece smooth and plished like structure distinguish from feldspar by the viaxial nature and nepheline is uniaxial negative
quartz
trace anounts if Fe that’s why its violet
amethyst
color resulting to trace amounts of Ti+4
rose quartz
color appears to result from trace amountd Al+3
smokey quartz
red colored chalcedony
carnelian
apple green colored as a result of colorstion from NiO
chrysoprase
alternating curving layers of chalcedony with different colors or different porosities
agate
alternating laters kf chalcedony of different colors or porosities arranged ib oarallel lines
onyx
green chalcedony containing red spots of jasper
bloodstone
occurs as nodules in limestone
layered rock deposited on the ocean floor
flint
chert
high temperature SiO2 found in ifneous rocks cooled rapidly diliceous volcanic rocks like rhyolites occurs as wedge shaped crystals in cavities assco with crustibalite and sanidine occurs as orthorhombic or monoclinic positive between 40-90 lower refractive incldices negative rwlief conpared to feldspar
tridymite
high temperature SiO2 polynorph thermally metamorphosed sandstones lining in open cavities fine graine crystals tetragonal uniaxial negativeoptic sign shows lower relief than quartz vut similar birefringence
cristobalite
higher temperature than the slbite component
anorthite
caused by incompleye reaction of crystals with liquid during cooling of a solid solution oscillatory normal skeme show ca rich cores and na rich tims but reverse possible under certain conditions
zoning
high temperature yo lower temperature changes from sanidine which is monoclinc to ortho monoclinic sanidine to microline is tricilinc
low releief and loe birefringence
alkali feldspar
equant habit simple twinning optically negative with a 2V of 20-50 distinguished fro nquaryz uniaxial positivr larger values of 2V
sanidine
common in alkali felds in granitic rocks and k al rich metamorphic rocks 001 and 010 rougher compared to quartz biaxial 2_mV orthoclase varies 60-105 either positive or negative 2V angle
orthoclase
lowest temperature form of alkali feldspar reareange from monoclinc to triclinic teinning conbination of albite and pericline twinning cross hatched pattern tartan twinning
microcline
na rich felds equal anounts of anorthite and orthoclase 2V shows a low 2V of 5 to 20 like sanidine optically negativr usually forms crystals with a tabulst elongated habit
anorthoclase
alkali rich mienrals that kccur ib low SiO2 high Na2O-K2O assoc pyroxenes and amphiboles aegerine and riebeckite
main are nepheline kalsilite and leucitr
feldspathoids
other minerals under feldpsathoids
sodalite
nosean
hauyne
plansr composition surface separating 2 indiv crystals twin law expressed a twin plane orthoclase twinned on teh braveno law eith 021 twin plane
contact twins
irregular composition surface separating 2 indiv defined by a twin or twin acis orthoclase twinned kn the carlsbad law with 001 as twin axis
penetration twins
parallel to one another plag shows this called albite twin law with 010 twin plane
polysynthentitic twins
notnparallel to one another chersoberyl 031 plane
cyclical twins
feldspar minerals plag and microcline ate common
triclinic system
twin law 019 incdicates that the twinning occurs perpendiculst to the b crystallographic acid common i nolaclg
albite law
has 019 twin axis result of monoclinic orthoclase amor sanidine transforming to mcirocline combination with labite twinning in microcline tartan twinning whrn this is combiend eith albute twinning
pericline law
msot common twins occur in planes 100 and 001 felds orthoclase snaidine both contact and penetration twind occue result accidents during growth
monoclinic system
001 forms a contact twin onserved in the mienral orthoclase diagnostic of orthoclase when it occurs
manebach law
[001] forms a penetration tein in yhe mienral orthoclase two intergrown cyrstals one rotated 180 from the other about the [901] axis kost common type of twinning in orthoclase
carlsbad law
021 forms a contact twin in the mineral orthoclase
braveno law
100 observed in gypsum
swallow tail twins
twin o nolanes parallel to a prism face common is 120 results in orthorhombic mienrals having cyclical twins
orthorhombic system
110 mineral aragonite chrysoberl anf cerussite gives pseudo hexagonal appearance
cyclical twins
monolcinic but has a angle hery close to 90 so it alpearance of an krthorhombic mineral teo types kf interpretation occurs 031 right angled cross and thr 231 cross about 60 degrees
staurolite law
011 forming cyclical contact twins minerals rutile and cassiterite shows this thpe of twinning
tetragonal
mienrals calcite and wuart common
hexagonal system
2 most common twin laws observed 0001 anf yhe rhombohedron 0113 contact yeund can occur as polysyntheric twins result from deformation
calcite twins
1120 result of penetration twin from transformation
brazil law
0001 penetration twin results from transformation
dauphine law
1122 contact twin tesults from accidents during growth
japanese law
quartz twinning
brazil law
dauphine law
japanese law
111 twin plane parallel to an octahedron occur sin spinel
spinel law
twin axis perpendiculat to an octahedral face adds 3 fold rotational symemtry
[111]
mienrlacpyrite shows mad eof interpretation of two pyritohedrond occurs in nvladd 2/m3 eith no 4 gold rotstion aces the [001] mineral apparent 4 fold symmetry about 3 leroenficular axes
iron cross
pure forsterite and fayalite melts at
1890
1205
during metamorphism kaolinite rqcts with quartz to form the mineral
pyrophyllite
occures in metamorphosed al rich sed rocks (metapelites) as >500 brownish color monoclini appear orthorhombic crystals crucifrom twins charac features
staurolite
orthorhombic occurs as granitic rocks best crystals fournd in granitic pegmatites
topaz
low temp 200-400 occurs in cracks in beind as metamorphic mienral essential mineral in greenschists which are emtamorphosed basalts
epidote
be2+ small cations large cations large anions
boron lithium
thorium uranium
fluorine hydroxyl
occurs in late stage granitic rocks in pegmatites assoc with quartz k felds li-mica tourmaline
beryl
fontains boron forms trigonal crystala triangular cross section striated prallel with the c axis
tourmaline
tourmaline fe richli rich
balck
green brown green and red
same structure as beryl at high temp but changes to an orthorhombic symmetry on cooling external is hexagonal but internal is orthorhombic occurs in al rich sed rocks been metamorphosed at tenperatures >500
cordierite
dark brown to balck occurs in igneous in some basalts coarse grtianed evidence of high temepfature inportabt mineral in matle peridotes
orthopyroxene
plutonic rocks composed of orthopyroxene and plag felds
norites
nagesi dark green
aegerine augite
forms amunder high pressure end member of clini
jadeite
between jadeite and augute and occurs in eclogite
omphacite
metamorphic equivalents of basalts formed under very high pressures and relatively low temperatures considts of two green omphacite and red brown garnet dense
eclogite
breaks into 90 cleavage and break into rectangular
dimaond shaped cross section
pyroxene
diamond
orthorhombic amphibole grey brown mineral forms elongate prisms occur in aggragates olivine rich ultramafic rocks
anthophyllite
2 end members of monoclinic amphiboles which id colorless pame green result of ca and mg bearing carbonate seds dolomites occur green konerals in metamorphosed basaltci rocks greenschists
tremolite pale green
actinolite
layered sturtufe in greenschists
chlorite
most wifespread amphibole dark green to black mineral common in intermediate to acidic granites important in metamorphosed equivalents of basaltci rocks amphibolites
hornblende
consist of hornblende and felds plag form higher temp than greenschist
amphibolites
amphibole is blue occurs in basaltic rocks metamorphosed at high pressures and low temperature
blueschists
mg rich vatieties are brown
phlogopite
hardness 2.5-3 fe rich varieties are black
biotite
formed by alteration of silicate kiwnrals tjay contain mg and fe (olvine augite hornblende biotite) reac temp range ~-00-500 wifespread late stage mineral fills holes in volanoc rocks componennt of greenschissts basalays metamorphosed at 300-500
chlorite
silicified replaced by microcrystalline quartz
fossilised wood
na tich alkali felds with >10%
anorthoclase
celavage of orthoclase and microcline a
001 and good prismatic 010 cleavage
known as green microcline
amazonite
carlsbad twinning componeneyd og granite and syenite important in gneisses
microcline and orthoclase
rhyolite and trachyte contain high twmp of
sanidine
temp of anorthite and albite
melts at 1560
1118
anhydrous framework silicates related yo alkali felds most important nepheline and leucite
feldspathoids
repated to albuge hexagonal 5.5-6
nepeheline
related to k felds forms white crystals with cubic smetey frim k ruch inverts terragonal on cooling symmetry external cubic form fmaous bearing of this miners is my.vesuvius pompeii A.D. 79
leucite
cubic one is deep blue feldspathoids
sodalite lazuritw
lazurite occurs togehter with calcite and pyrite
lapis lazuli
monoclinic tabulat 010 perfect cleavage attractiv eaggregates are desert roses occurs with ore minerals in veins
gypsum
white tabular orthorhombic perfect 001 cleavage high density for a non metallic 3-3.5 occurs in ore minerals in veins
barytes
hecagonal longprismatic cyrstals greenish pegmatites large green hexagons
apatite
plutonic rocks classified acc to their modal monetal content and actual mienral content in volume % classification known as
streckeisen
rocks with >60% foid minerals amongst light mienrals are rarw and are called
fodolites
used for equivalent volcanic rocks of foidolite
nephelinite
differentiate gabbro and diorite
ga bro contains plag An>50 while diorite has An<50
consists dominantly of plag clinopyroxene (augite) olivine and orthopyroxene (hypersthene) field 10
gabbro
clinopyroxene + plag
gabbro
opx + plag
norite
olivine+ plag
troctolite
cpx+opx+plag
gabbronorite
olivine + cpx+ plag
olivine gabbro
melanocratic
m 65-90
meso mesonorite
m 35-65
leucogabbro leuco when
M is 10-35
plutonic rocks contain opx norite is part of this family
charnockitic
used for hypersthene granite include mangarite and jotunite assoc with large bodies of anorthosite in dominant mafic mineral in opx
charnockitic
hypersthene monzonite
mangerite
hypersthen monzonorite
jotunite
ultramafic rocks >40% olivine
peridotites
otyoes of peridotirw
dunite
harzburgite (olivine+opx)
wehrlite (olivine and cpx)
lherzolite (olivine+ 2 pyroxenes)
rocks with >60% pyroxene
pyroxenites
feeders to lava flows may have glassy margins but phaneritic centres
chilled margin formed by rapud cooling against cd wall rocks
occur in large and minor intrusions
synonyms for microgabbro commonly used for dykes and sills for appropriate composition
dolerite and diabase
granitic rock in ec the groundmass quartz and alkali felds occur in a micrographic intergrowth
granophyre
fine grained granitic rocks which typically occur as dykes veins or patches in or assoc with granitic intrusions
aplite
porphyritic melanocratic rock type usually occurs in minor intrusiond feldspar/feldspathoids only occur in the groundmass biotite amphibole are common hydrothermal alteration of mafic mienrals is widespread calcite is a common primary mienral geochemically distinct
lamprophyres
similar to lamprophyre but with more wxtreme chemical composition
lamproite
imorotant mienrals are olivine serpentinised mg rich mica phlogopite pyroxenes garnet snd carbonates formed at high pressure
kimberlite
jcolor index of basts to andesite
M>35
M<35
used for dark volcanic rocks includes basalts and andesites
TAS classification
volcnaic equivalens of foid sywnites ex: nepheline syenits in volcani leucite might be and important foid mienrlas
phonolites
differentiate basanites and tephrites
basanite >10% olivine
tephrite <10%olivine
amount of olivine is estimated on the basisi of the chemical composition of yhe rock recalculated j germs of simple mineral proportions
normative comoposition
hypothetical mienral composition of a rock calculated from its chemical composition
volume % mienrals present
modal
pearly grey glass with concentric curved fractures
perlite
useful chemical prameywrs in volcanic rocks sio2 and na2o+k2o
total alkalies
si contentn ultrabasic
basic
intermediate
acid
<45
45-52
52-63
>63
basalts
andwsites
rhyolites
basic
intermediate
acidic
ultrabasic TAS
foidite picrobasalt basanite (tephrite)
high pressures so high high the pmag is not stable green cpx and red brown garnet
eclogite
volcnaic rocks with 41-45% sio2 and <3% tas are
picrobasalts
basic rocks with 45-52% sio2 and <5% total alkalies
basalts
52-57%
basaltic andesites
57-63%sio2 intermediate volcnaic rocks relatively low total alkali contents
andesites
> 63% are acidic volcanics grade into rhyolites
dacites
69-77% sio2
rhyolites
differentiate trachyte and trachydacite
<20% normative quartz
>20% normative quartz
fiery clouds deposited from one of the most vioelny types of volcnaic eruption pyroclastic floes
ignimbrites
flattened glassy fragments
flames
rock composed entirely of blocks
volcanic breccia
volcanic equivalent kf peridotite but is rare
komatiite
sio2 content increases from increases from left to right from for the ultramaficperidotite to for the felcsic acidic granite/rhyolite
<45%
>63%
decreases from lef tto right
%mafic minerals m
consists of 90% oliving+pyroxene and 10% ca rish plags
peridotite
consists of ca rich plags and pyroxene and olivine
gabbros/basalts
dominated by plag and hornvlende+puroxene
diorites/andesites
contain quartz na rich plag and hornblende + kfelds and biotite
granodiorites/dacites
dominated by qrz and kfelds with na rich plag and minor mica and hornvlende but mica are rare in volcnaics
granites/rhylolites
forms when the temp of mantle peridotite id above its solidus
basalt
produces the basaltic magma that is erupted along mid ocean ridges
10-25% melting of peridotite
hydrous mienrlas release water during subduction
chlorite serpentine hornblende
temeprature of baslatic lava and rhyolitic
1200
900
temp of a melt is that teno when the first crustals vegin to form
liquidus
lst drop of melt crystallizes
solidus
dru basalt the temp of liquidus and solidus
1200
990 so basalt crystallizes >200
for dey rhyolite at surface the liquidus and solidus is
900
750
grabboric bodies consist largely og plag rich layers alternating with cpx layers
layered gabbros
mienrals are removed in sequence and the magma changes in composition in consequence
fractional crystallizaiton
augute and olivine will sink to the floow of the chamber this mineral will form above dunite
wehrlite
first plag to cyrstallize wil have a compostion of
An75
overloes ghe earlier formwd dunite and wehrlite
olivine gabbro
where is bushveld it ruison located
south africa
where is chemical weathering most effective?
chemical weathering
components of rust
goethite and hematite
final product of breccia
sandstone
how mang percent when sand is compacted and mud
10-20%
50-80%
coarse grained sandstone containing feldspar as well as qtz grains
arkose
forms marine wnvi result of redistribution of unconsolidated sediments accumulation downslope deep sea floor contain a range of grain size in a fine grained matrix and have yhe unusual name show graded sgructure grain size decreases upwards
greywacke
formed in an environment where clay deposited simultaneously gives rise to a micture of limestone and clay
marl
limestone contains of microscopic shelss of plankton called
foraminifera (chalk)
lime mud can consolidate to give very fine grained limestone called
micrite
colors the shale black and turns into oul dhale when this happens
soft parts of plankton mix with muc on the sea floor and be incorporated into shale
when 80% of the water has evaporated what forms? 90%
gypsum
halite
sylvite
beige in color and used as facing stone direct precipitation from water w/oorganism involved of linestone
limestone
layers are selarated fron each pther by
bedding planes
alternativ e term for layering
stratificiation
several layers jointly referres as
strata
usually named after a place (type of locality) and the rock type
formation
beds that ate inclined relative to a thicker stratum in wc they occur forms when sand/silt prticles ate deposited on a slope
cross bedding
rock fragmentx on the surface sometimes develop charac shapes reflecting different wind directions polished rocks are
dreikanted
a thin graded layer reflects deosition of one year no new materail enters the lake fine grained material may settle out
varve
wht are deposited in foreset
silt and mud
become buried of the foreset deposits
bottomsets
dominated by shell fragments and occur today on tropical islands far from maonland wc could supply clastic mayerial oites spherical carbonate structures are common in
shallow marine carbonate deposits
deep sea floor is covered by these and wx are small metal rich spehcrical bodes that represent potential ore reserves
manganese nodules
temp and pressure conditions of igneous sed and metamorphic
650-1250 sirface to ca 10kb
<15” surafce conditions very low pressure
150-180 upto 10 kb
clay form large mineral grians i metamorphic rocks
porphyroblasts
metamorphic equivalent of phenocrysts in igneous rocks
porphyroblasts
convertion
1 atm
1kb
1 bar
1000bar
100vmrgapascal mpa
0.1 gigapascal (Gpa)
non foliated meta rocks that have been baked because of their proximity to an intrusion relatively fine rained massive rocm
hornfels
clay rich sed rocks prior to mwtamorphism
metapelitic
in the presence of water, forsterite breaks down in the presence of water at >200
serpentine
mg rich silicate mirntal that can be formed from the metamorphism of olivine tich rocks is
talc
in metamorphic petro clay rich sed rocks are
pelites
metamorphic products are
metapelites
rich in aluminum
pelites
phyllosilicates become oriented perpendiculat to the direction of oressure to dorm a distinct parting called
slaty cleavage
high temp white mica muscovite vegins to form from the breakfow of clay minerals crenulated
phyllite
metamorphic foliation in schists
shistosity
part of grabite that did not melt
restite
after gneiss granite will form then the mixed rock is called
migmatite and the granitic part of this is igenoues
deformation of mafic rocks gabbro andesite gabbro diorite greenish color of this meta rock is due to chromite and chlorite white albite is also present and as the grade increases these mienrals break down as horbblende(black) and plag (white)
greenschist
meta rock consisting largely of these two minerals is an
amphibolite
high pressure low temp baslatic rocks metamorphosed blusichcolor glaucophane (amphibole) plag felds is unstable mafic rock from plag and augite to garnet and omphacite eclogite is red green coz garnet is red and onphacite is green>90% mafic mineral in ultramfic rock
bluschists
dolomite skeme
trenolite amphibole
diopside pyroxene
forsterite olivine
state the protolith
pelite
basic
ultrabasic
calc siliciate
quartzo frldspathic
shale
mafic igneous rock basalt andesite gabbro diorite
ultramafic peridotite
limestone dolomite marl a mixture of clay and limestone
granite rhyolite
metamorphosm befins at
150 C
metapeliye will begin to melt at
650
at what tem pdoes kaolinite reacts with quartz
200-250
w/o water what does kaolinite forms to
pyrophyllite a phyllosilicate
form from slate
chlorite
formation pf pyrophyllite and chlorite takes place under
low grade metamosphic conditions
wher eis stayrolite seen
schists
new mienrals sequence
prophyllite
chlorite
white kica
biotite
andalusite/kyanite
garnet
kfelds
sillimanite
enough white mica and then this mienral will form
phyllite
after the andalusite and kyanite what is next
dark mica biotite
alumnium braring mienrals occurs in schosts
cordierite
staurolite
garnet
kfelds forms from the breakdown of muscovite after the dakr biotite
sillimanite is formed
beru high grade metamorphic rocms
migmatites
progression form shale to gneiss called
prograde mwtamorphism
good indicator of metamorphic grade since they only appear when dpecific pt conditions are reached
index minerals
line separating two index mienrals
isograd
cannot form in non pelyitic rocks( such as metamorphosed limestones or sandstones which often occur together with metapelites
al2sio5 polymorphs
metamorphic zones index miebrals
sillimanite zone
kyanite sone
garnet zone
biotite sone
chlorite zone
reqyires water
retrograde metamorphism
pelit emetamorphosed at 5kb and 550 may contiang
wtz muscovite biotite almandine granet and sillimanite
garnet sillimanite mica schists
qtz bearing dolomitic limestone metamorphosed under the same t and p conditions will consist
calcite diopside (a cpx) and palg felds and hornblende (foliated amphibolite)
form in rocks of appropriate composition at a very low grade of metamorphism
zeolite
forms as a tesult of thermal metamorphism (geaying at low pressure) rocks are bot foliated and are usually fine graiend and brittle spotted because of the growtn of nrw porphyroblasts(andalusite cordierite in metapelites)
hornfels
dgelops under low to meduum grades of metamorphism charac appearanc rof metamorphosed basaltic tocks that becone this under low to medium grades of metamorphism dir to chlorite and epidote
greenschist
dveelops under medium to high grades of metamorphism bamed after basatic rocks that develop plat feldspar and hornblende (an amphibole) under
amphibolite facies
forms under high hrades of metamorphism rocks are commonly granular in alpearance rocks begin to mely in the presence of water under granuliye facies conditiond form udner dry conditiond melting could not tka eace charac mineral is orthopyroxene
granulite facies
formsu nder high P and low T named after charac appearance of metamorphosed basaltic rock become blue due to glaucophane a blue ampuibole
blueschists
develops under high pressure conditions consists largely of reddish garnet (pyrope rich) and greenish cpx (ompahcite) formed when plag in metabaslatic rocks becomes unstable becaus eof high pressure
eclogite
100
15
50-20
geothermal gradient temp
hornfels
blueschists
greenschists amphibolite grabulte
is a metabasalt
blueschist facies
result of the combined effects of deformation and heating and is also known dynamothermal metamorphsim
regional metamorphism
product of regional metamorphism
caledonian mountain
contact metamorphism around a pluton increasing temperature
unmetamorphosed
chlorite
muscovite
biotite
hornfels
garnet
staurolite
sillimanite
pluton
geolgoical environment this occurs in the vicinity of faults
dynamic metamorphism
no deformation during metamorhpsicj no shisyosity develops and basaltic chanege sto greenschisys
ocean floor metamorphism
occur in the precambrian shield and mountai nbelts
metamorphic to kd
dominated by gneissic tocms
precambrian shields
young mountain belt stretches east west from the alpd to hinalayad formed as a result of tje aftican and indian continental plates with the
european and asian continental plates
represent the root zones of ancient mountain belts
gneissic areas
compressed pumice fragments in a tuff
fiamme
ovoid blobs created by liquid immiscibility mingled magamas or filled vesicles
ocelli
ovoid masses of radiating crystals concentrically banded found in some granites
orbicules
centimenter scale texture subparallel to dendritic growth of olivine cryatsls in some quenched ultramafics
spinifex
concentric fracture pattern resulting from contraction of some volcanic glasses ipon cooling
perlitic
large ovoid structures representing gas bubbles in devritified rhyolitic glass
lithophysae
