DAY 2 Mineralogy

Question 1

when did the mohs scale established

Answer 1

1824

Question 2

when was mohs hard scale invented?

Answer 2

1894

Question 3

who invented the mohs scale?

Answer 3

frederic m

Question 4

who invented the mohs scale?

Answer 4

frederic mohs

Question 5

who invented mohs scale

Answer 5

frederic mohs

Question 6

how man

Question 7

transition elements within crystal lattices that can change the color of a mineral

Answer 7

chromophores

Question 8

transition elements within crystal lattices that can change the color of a mineral

Answer 8

chromophores

Question 9

how many silicates in mohs scale

Answer 9

4 talc orthoclase feldspar quartz topaz

Question 10

how many hydrous in mohs scale

Answer 10

4 talc gypsum apatite topaz

Question 11

how many hexagonal in mohs scale

Answer 11

calcite apatite quartz corundum

Question 12

how many isometric in mohs scale

Answer 12

2 fluorite and diamond

Question 13

how many isometric in mohs scale

Answer 13

2 fluorite and diamond

Question 14

how many orthorhombic in mohs scale

Answer 14

1 topaz

Question 15

how many monoclinic in mohs scale

Answer 15

3 talc gypsum orthoclase feldspar

Question 15

how many orthorhombic in mohs scale

Answer 15

1 topaz

Question 15

how many isometric in mohs scale

Answer 15

2 fluorite and diamond

Question 15

ratio of velocity of light in air and the velocity of light in a medium

Answer 15

refractive index

Question 15

this has a single refractive index

Answer 15

isotropic minerals

Question 15

more than one refractive index

Answer 15

anisotropic minerals

Question 15

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

Answer 15

double refraction

Question 16

minerals that are deformed through compressive stress

Answer 16

malleable

Question 17

also called hypdiomorphic hypautomorphic sub idioblastic

Answer 17

suhedral

Question 18

also called allotriomorphix xenomorphic xenoblastic

Answer 18

anhedral

Question 19

smallest unit of pattern that when repeated by a set of symmetry operations will generate the long range pattern characteristics of crystal

Answer 19

motif

Question 20

point used to represent any motif

Answer 20

node

Question 21

set of rules that govern the repetition of motifs which can produce two or three dimensional patterns with long range order

Answer 21

symmetry operations

Question 22

specific length and direction of systematic displacement by which the pattern is repeated

Answer 22

unit translation vector

Question 23

smallest units of meshes which contains at least one node and the unit translation vectors

Answer 23

unit meshes

Question 24

groups denoted by their rotational and reflection symmetry

Answer 24

plane point groups

Question 25

combines translation parallel to an axis with rotation about the axis

Answer 25

screw rotation

Question 26

how many plane lattice groups

Answer 26

17

Question 27

recognized groups that are based on the total symmetry of their plane lattices

Answer 27

plane lattice groups

Question 28

3d equivalents of the 2d plane point groups

Answer 28

space point groups

Question 29

3d patterns of points produced from the translation of nodes of space point groups

Answer 29

space lattices

Question 30

defined on the basis of the external symmetry of mineral crystals and belong to six crystal systems with its own characteristic symmetry

Answer 30

crystal classes

Question 31

parallelipiped whose edge lengths and volume are defined by the 3 unit translation vectors

Answer 31

unit cell

Question 32

orientation of the unit cell edge

Answer 32

crystallographic axes

Question 33

consists of a 3d set of one or more crystal faces that possess similar relationship to the crystallographic axes

Answer 33

crystal forms

Question 34

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

Answer 34

closed crystal form

Question 35

what are the crystal class of isometric?

Answer 35

hexoctahedral hextetrahedral gyroidal dipyroidal tetraoidal

Question 36

what are the crystal class of tetragonal?

Answer 36

ditetragonal-dipyramidal ditetragonal-pyramidal tetragonal scalenohedral tetragonal trapezohedral tetragonal dipyramidal tetragonal disphenoidal tetragonal pyramidal

Question 37

what are the crystal class of hexagonal?

Answer 37

dihexagonal dipyramidal dihexaginal pyramidal ditrigonal dipyramidal hexagonal trapezohedral hexagonal dipyramidal hexagonal pyramidal trigonal dipyramidal

Question 38

crystal class of rhombohedral/trigonal

Answer 38

hexagonal scalenohedral ditrigonal pyramidal trigonal trapezohedral trigonal pyramidal rhombohedral

Question 39

crystal class of orthorhombic?

Answer 39

rhombic ipyramidal rhombic pyramidal rhombic disphenoidal

Question 40

crystal class of monoclinic?

Answer 40

prismatic sphenoidal domatic

Question 41

crystal class of triclinic?

Answer 41

pinacoidal pedial

Question 42

consists of a single face

Answer 42

pedion

Question 43

a pair of parallel faces

Answer 43

pinacoid

Question 44

has 3 parallel to an axis

Answer 44

prism

Question 45

has 3 or more faces that intersect at an axis

Answer 45

pyramid

Question 46

a pair of faces symmetrical about a mirror plane

Answer 46

dome

Question 47

pair of faces symmetrical about an axis of rotation

Answer 47

sphenoid

Question 48

proportional lengths of the 3 crystallographic axes

Answer 48

axial ratio

Question 49

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

Answer 49

unit plane

Question 50

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

Answer 50

weiss parameters

Question 51

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

Answer 51

miller indices

Question 52

what are the forms under isometric

Answer 52

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

Question 53

forms under tetragonal

Answer 53

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

Question 54

forms under hexagonal

Answer 54

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

Question 55

forms under trigonal?

Answer 55

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

Question 56

orthorhombic forms?

Answer 56

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

Question 57

monoclinic forms?

Answer 57

monoclinic prisms 4 rectangular faces gypsum staurolite clinopyroxene pinacoids 001 010 110 pair to rectangular perpendicular to a b c axis sphene epidote micas

Question 58

triclinic forms?

Answer 58

pinacoids 2 parallel faces kyanite plagioclase microcline pedions single face rhodonite wollastonite

Question 59

what is the weight of a nucleus and protons

Answer 59

1.00867 amu nucleus 1.00728 amu protons

Question 60

who developed the periodic table of elements

Answer 60

dmitri mendeleev march 1 1869

Question 61

the amount of energy required to strip an element of an electron from its outermost shell

Answer 61

ionization potential

Question 62

mineral groups that has no group or subgroup?

Answer 62

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

Question 63

what are the mineral groups of carbonates?

Answer 63

calcite group CO3^-2 dolomite group aragonite group

Question 64

groups under the mineral group halides

Answer 64

anhydrous halides hydrous halides CL-1 Br1 F1

Question 65

what are the subgroups under hydroxides?

Answer 65

brucite type group gibbsite type group OH1

Question 66

what are the groups under native element

Answer 66

metals group: gold group platinum group iron group semimetals group non metals group

Question 67

groups under oxides?

Answer 67

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

Question 68

groups under silicates?

Answer 68

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

Question 69

groups under sulfates?

Answer 69

anhydrous sulfates hydrous sulfates SO4^-2

Question 70

this theory suggests that beams of light consist of material particles that spread in all directions from luminous bodies

Answer 70

corpuscular theory

Question 71

particle of lights which are discrete packets of energy that interact with atoms at the subatomic level

Answer 71

photons

Question 72

assumes that units of quanta radiates discontinuously from radiating oscillators in a black body

Answer 72

quantum theory

Question 73

surface that represents the direction of the propagation of light energy simultaneously in same place

Answer 73

wavefront

Question 74

line at any point in the direction of the propagation of light perpendicular to the surface of a wave front

Answer 74

wave normal

Question 75

perpendicular to the wavefront represents the direction of propagation of light

Answer 75

ray of light

Question 76

materials whose light passing through them have light rays parallel to the wave normal and perpendicular to the wavefront

Answer 76

isotropic

Question 77

light passing have light rays that are not parallel to the wave normal

Answer 77

anisotropic

Question 78

curve that may represent that combined movement around a circle with movement along a straight line

Answer 78

displacement

Question 79

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

Answer 79

vibration direction

Question 80

filters the light and eliminate the orange light

Answer 80

base blue filter

Question 81

polarizes light in a single wave direction generally only those oriented in the N-S direction

Answer 81

sub stage polarizer (lower polarizer)

Question 82

controls the amount of light passing through the specimen

Answer 82

sub stage iris diaphragm

Question 83

controls and focuses the light from the light source

Answer 83

sub stage condenser

Question 84

used to retard the light coming through the specimen

Answer 84

intermediate accessory plates

Question 85

polarizes light in a single wave direction only those in the E-W direction

Answer 85

intermediate analyzer (upper polarizer)

Question 86

used to observe interference figures

Answer 86

intermediate bertrand lens

Question 87

magnifies the observed image

Answer 87

intermediate objective lens

Question 88

adjusts the stage's distance from the objective lens

Answer 88

stand coarse adjustment knob

Question 89

focuses and sharpens observed image

Answer 89

stand fine adjustment knob

Question 90

let's users to observe the image produced

Answer 90

Assembly: Ocular Part: Eyepiece

Question 91

ratio of the wave normal velocity in a vacuum regardless if the medium is isotropic or anisotropic

Answer 91

refractive index

Question 92

light consists of a single wavelength

Answer 92

monochromatic light

Question 93

component of light vector that lies parallel to the wave front and perpendicular to the direction of the propagation except for anisotropic minerals

Answer 93

light vector

Question 94

light vector that measures the electrical displacement

Answer 94

electric light vector

Question 95

measures magnetic displacement

Answer 95

magnetic light vector

Question 96

147nm retardation dimensions are usually NW-SE

Answer 96

mica plate

Question 97

550nm retardation dimensions are usually NW-SE

Answer 97

gypsum plate

Question 98

various retardation to determine the order of the interference color exhibited by a mineral

Answer 98

quartz wedge

Question 99

optically positive if the interference color between the melatope ; negative if melatope

Answer 99

decreases; increases

Question 100

optically positive if the colors move in along the trace of the OAP and out along the ON

Answer 100

negative if the colors MOVE OUT along the trace of the OAP and in along the ON

Question 101

monoclinic variety of albite

Answer 101

monalbite

Question 102

lapiz lazuli, chalcedony amazonite and jasper were cut and curved where?

Answer 102

babylonia

Question 103

it is also known an emerald filter

Answer 103

chelsea

Question 104

also called flame fusion, was the first commercially successful method of manufacturing synthetic gemstones, developed in the late 1883

Answer 104

Verneuil method

Question 105

also called as crystal pulling

Answer 105

Czochralski process

Question 106

heavy walled steel cylinder closed at one end

Answer 106

autoclave or bomb

Question 107

a process for growing single crystal or crystals of a metal or compounds. ruby and emerald are grown here

Answer 107

Flux method

Question 107

which materials dyeing used

Answer 107

chalcedony jade and turquoise

Question 107

gems successful for heat treatment

Answer 107

zircon quartz beryl topaz and zoisite (tansanite)

Question 108

clinonet is also known as what?

Answer 108

clinonet

Question 109

what is called as german silver?

Answer 109

iron nickel zinc

Question 110

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

Answer 110

snells law

Question 111

degree of visibility of a transparent mineral in an immersion medium or the difference between the refractive index between a mineral and a medium

Answer 111

relief

Question 112

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

Answer 112

becke line method

Question 113

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

Answer 113

oblique illumination method

Question 114

composed of two rays

Answer 114

cross polarized light

Question 115

travels in the low refractive index direction

Answer 115

fast ray

Question 116

travels in high refractive index

Answer 116

slow ray

Question 117

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

Answer 117

retardation

Question 118

twinning where two crystals form as penetration twins

Answer 118

carlsbad twinning

Question 119

lamellae are both observed with respect to each other and every alternate twin plate or slab has an identical atomic structure

Answer 119

lamellar twinning

Question 120

two kinds of repeated twinning in thin sections with one set of twins arranged at 90 to other set

Answer 120

tartan twinning

Question 121

outer rim is composed of low temp mineral compared to its center which is composed of high temp mineral of the same solid solution

Answer 121

normal zoning

Question 122

outer rim is composed of high temperature mineral compared to its center which is composed of low tem mineral of the same solid solution

Answer 122

reverse zoning

Question 123

step like progression of higher temp mineral tot he lower temp mineral at margins with local reversals in adjacent zones

Answer 123

oscillatory zoning

Question 124

minerals extinct at certain angles that may be due to being deformed

Answer 124

undulatory extinction

Question 125

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

Answer 125

zoning

Question 126

divisions in the michel levy chart for every 550um that is marked by a reddish hue interference color

Answer 126

order

Question 127

lens inserted below the oculars used to observe interference figures

Answer 127

bertrand lens

Question 128

bands of interference colors which increases in order form the melatope to the outer bands

Answer 128

isochrome

Question 129

arms of the interference figure

Answer 129

isogyre

Question 130

point where the isogyres cross and where the optic axis emerges

Answer 130

melatope

Question 131

specific direction in anisotropic minerals where only one ray travels through the mineral

Answer 131

optic axis

Question 132

is a sphere and indicatrix with constant radius due to light travelling in all directions with the same velocity

Answer 132

isotropic indicatrix

Question 133

an ellipsoid that revolves around the crystals c axis optic axis

Answer 133

uniaxial indicatrix

Question 134

anisotropic minerals where minerals with tetragonal and hexagonal crystal system belong which have only one optic axis

Answer 134

uniaxial minerals

Question 135

semi axis perpendicular to the c axis that has length proportional to the RI perpendicular to c and is associated with the ordinary light

Answer 135

omega

Question 136

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

Answer 136

ordinary ray

Question 137

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

Answer 137

epsilon

Question 138

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

Answer 138

extraordinary ray

Question 139

intermediated refractive indices possessed by intermediate velocities of epsilon that are associated with other e ray directions

Answer 139

epsilon prime

Question 140

perpendicular to the optic axis the c axis and ordinary ray path

Answer 140

circular section

Question 141

viewed when the optic axis is parallel to the stage which is parallel to the extraordinary wave vibration direction

Answer 141

principal section

Question 142

other section parallel to the stage that have two rays pass through the crystal path ans is associated with epsilon prime

Answer 142

random sections

Question 143

a sign that denotes ray is associated with either the larger or smaller refractive index

Answer 143

optic sign

Question 144

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

Answer 144

uniaxial positive

Question 145

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

Answer 145

uniaxial negative

Question 146

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

Answer 146

gypsum plate

Question 147

observed when the optic axis is perpendicular to the stage so that the circular section is parallel to the stage

Answer 147

centered uniaxial optic axis OA figure

Question 148

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

Answer 148

off centered optic axis OA figure

Question 149

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

Answer 149

uniaxial flash figure

Question 150

a triaxial ellipsoid the represents the refractive indices of a biaxial mineral in every direction

Answer 150

biaxial indicatrix

Question 151

class of anisotropic minerals where minerals are triclinic monoclinic and orthorhombic crystals systems belong which have only two optic axes

Answer 151

biaxial minerals

Question 152

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

Answer 152

alpha

Question 153

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

Answer 153

gemma

Question 154

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

Answer 154

beta

Question 155

elliptical XY plane

Answer 155

optic plane

Question 156

elliptical XZ plane perpendicular to the Y

Question 157

elliptical XZ plane perpendicular to the Y

Answer 157

optic axial plane

Question 157

circular sections in a biaxial indicatrix that are perpendicular to the two sections

Answer 157

optic normal sections

Question 157

the angle between the optic axes measured in optic plane

Answer 157

optic angle 2V

Question 158

line parallel to the y axis of a biaxial indicatrix that intersects the optic normal sections

Answer 158

optic normal

Question 159

line in the optic plane that bisects the optic angle between the optic axes

Answer 159

optic normal

Question 160

complementary line that bisects the optic angle that may either 2Vx or 2Vz depending on the mineral optics

Answer 160

acute bisectrix bxa

Question 161

accessory plate used for minerals with high birefringence to easily determine their optic signs

Answer 161

quartz wedge

Question 162

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

Answer 162

iron rich bichemical sedimentary rocks

Question 163

constitutes 60% of the iron ores

Answer 163

banded iron formation

Question 164

type of BIf dominate the archean iron rich sedimentary rocks that formed between 3.8 ga and 2. 6 ga

Answer 164

algoma type BIF

Question 165

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

Answer 165

superior type BIF

Question 166

iron formation contained superior type of BIF which formed in fairly shallow water environments on passive continental shelves with limited influx of detrital sediments

Answer 166

granular iron formation

Question 167

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

Answer 167

ironstone

Question 168

contain less than 30% gravel sized clasts and sand mud ratio of <1:1 in their detrital fraction

Answer 168

mudrocks

Question 169

smectite rich that formed from the alteration of volcanic as deposits from explosive eruptions

Answer 169

bentonite

Question 170

at what temp and pressure does diagenesis occur?

Answer 170

~150 +- 50 degrees celcius and ~0.3 kbar

Question 171

early shallow diagenesis that occurs shortly after burial

Answer 171

eodiagenesis

Question 172

later deeper diagenesis

Answer 172

mesodiagenesis

Question 173

even later and shallow diagenesis that occurs as sedimentary rocks approach the surface due to erosion

Answer 173

telodiagenesis

Question 174

diagenetic product of plastic grains that can be difficult to distinguish from detrital matrix constituents

Answer 174

pseudomatrix

Question 175

most abundant group of biochemical sedimentary rocks and constitute about 15% of all sed rocks

Answer 175

carbonates

Question 176

also called as allochems sand to gravel sized carbonate particles that include shells ooids and limeclasts and peloids

Answer 176

grains

Question 177

also called as allochems sand to gravel sized carbonate particles that include shells ooids and limeclasts and peloids

Answer 177

grains

Question 178

mud sized carbonate particles in limestones and dolostones

Answer 178

micrite

Question 179

process where micro boring activity of blue green cyanophyt texture

Answer 179

micritization

Question 180

emphasizes the texture of carbonate rocks

Answer 180

dunham classification

Question 181

emphasizes thecomponents of carbonate rocks

Answer 181

folks classification

Question 182

carbonate rocks with gravel sized particles

Answer 182

calcirudite/dolorudite

Question 183

carbonate rocks with sand sized particles

Answer 183

calcarenite/dolarenite

Question 184

carbonate rocks with mud sized particles

Answer 184

calcilutite/dololutite

Question 185

composed of lithified colluvium deposited from mass wasting

Answer 185

diamictite

Question 186

less than 30% gravel sized clasts and a sand:mud ratio of >1:1 in their detrital fraction

Answer 186

sandstones

Question 187

sandstones containing 75-95% quartz grains with F:L ratio 1:>1

Answer 187

subarkose

Question 188

sandstones containing 75-95% quartz grains with F:L ratio of 1:> 1

Answer 188

sublitharenite

Question 189

rock fragment rich sandstones

Answer 189

lithearenite

Question 190

contains less than 75% quartz grains with F:L ratio between 1:1 to 3:1

Answer 190

lithic arkose

Question 191

contains less than 75% quartz grains with F:K ratio between 1:1 to 1:3

Answer 191

feldspathic litharenite

Question 192

how many percent is sed rocks in earths surface

Answer 192

85%

Question 193

quick method of determining the phi size value for any percentile

Answer 193

sorting coefficient

Question 194

more complicated measure of sorting that involves finding values that are one standard deviation and two standard deviations above and below the mean

Answer 194

inclusive graphic standard deviation

Question 195

rod shaped particles that have an elongate cylindrical that have on axis much longer than the other two

Answer 195

prolate

Question 196

disk shaped particles that have a flattened cylindrical or disk like shape where two saxes are shorter than the other two

Answer 196

oblate

Question 197

particles that have a flattened shape where the 3 axes have 3 different lengths

Answer 197

bladed

Question 198

gravelstones with an interior source eroding from the same source and lithifying in place making the clasts and matrices compositions uniform

Answer 198

intraformational

Question 199

compositions derived outside of depostional basin with the clasts and matrices composition different from each other

Answer 199

extraformational

Question 200

more than 90% of the framework clasts consisting of a single or few resistant rocks and minerals

Answer 200

oligomict

Question 201

clasts of different compositions that are prone to weathering and erosion

Answer 201

petromict

Question 202

clasts composed of a single composition

Answer 202

monomictic

Question 203

2-4 different types of parent rocks

Answer 203

diamictic

Question 204

clasts with numerous amounts of types of composition

Answer 204

polymictic

Question 205

the total overall retardation is greater than that exhibited prior to the accessory plate being inserted

Answer 205

positive elongation

Question 206

what are the isotropic minerals with low relief

Answer 206

halite halloysite antigorite cliachite collophane

Question 207

what are the isotropic minerals with moderate relief

Answer 207

opal fluorite lechatelierite sodalite analcime hauyne

Question 208

what are the isotropic minerals with moderate to strong relief

Answer 208

periclase garnet group grossularite pyrope almandite spessarite uvavorite andradite

Question 209

what are the isotropic minerals with very high relief

Answer 209

limonite spinel chromite perovskite sphalerite

Question 210

do not affect the polarization direction of the light which has passed through lower polarizer

Answer 210

isotropic minerals

Question 211

will appear dark or extinct every 90 degrees of rotation of the microscope stage

Answer 211

anisotropic minerals

Question 212

produce elongate grains and cleavage are distinguishable

Answer 212

biotite hornblende plag

Question 213

production of plane polarized refractive index

Answer 213

nicol prism

Question 214

minerals that exhibit parallel extinction

Answer 214

orthopyroxene biotite

Question 215

minerals that exhibit inclined extinction

Answer 215

clinopyroxene hornblende

Question 216

minerals that exhibit symmetrical extinction

Answer 216

amphibole calcite

Question 217

minerals that exhibit no cleavage

Answer 217

quartz olivine

Question 218

measures double refraction

Answer 218

snells law

Question 219

how many known minerals

Answer 219

4000 but 50 are common

Question 220

refractive index varies inversely with wavelength snells law

Answer 220

dispersion of light

Question 221

cleavage exhibits 56- 124 degrees

Answer 221

amphibole group

Question 222

two segments of one grain go extinct at different times as the stage is rotated

Answer 222

simple twins

Question 223

the segments are joined by a smooth twin plane separating the segments

Answer 223

contact twins

Question 224

the segments are joined by an irregular contact

Answer 224

penetration twins

Question 225

consists of numerous twin segments joined on parallel twin planes

Answer 225

polysynthetic twinning

Question 226

the separation of a single homogeneous mineral into two or more distinct minerals in the solid state

Answer 226

exsolution or unmixing ex: perthite albite exsolution from orthoclase at about 56 degrees celsius

Question 227

successive layers of sheet structure show regular variations in their orientation occurs in micas and clay

Answer 227

polytypism

Question 228

this mineral is colorless not pleochroic anhedral no cleavage very low relied uniaxial and length is slow

Answer 228

quartz

Question 229

colorless but cloudy not pleochroic subhedral to anhedral 2 cleavage directions low relief biaxial carlsbad and tartan twinning

Answer 229

alkali feldspars

Question 230

colorless no pleochroic euhedral to anhedral perfect cleavage directions low relief weak birefringence polysynthetic albite carlsbad pericline twinning triclinic feldspars

Answer 230

plag felds

Question 231

An0 to An10

Answer 231

albite

Question 232

an90- an100

Answer 232

anorthite

Question 233

intergrowth where soda rich phase predominates over potash rich phase

Answer 233

antiperthite

Question 234

their atomic ration exceeds that of alkali feldspars

Answer 234

feldspathoids nepheline sodalite leucite

Question 235

colorless not pleochroic high relief no to poor cleavage strong birefringence parallel extinction length slow

Answer 235

olivine

Question 236

F065-FO0

Answer 236

fe rich igneous rock

Question 237

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

Answer 237

pyroxenes

Question 238

orthorhombic orthopyroxenes

Answer 238

enstatite bronzite hypersthene ferrosilite

Question 239

monoclinic ca mg fe pyroxenes

Answer 239

augite pigeonite diopside hedenbergite

Question 240

sodic pyroxenes

Answer 240

aegerine-jadeite

Question 241

colored with varying pleochroism slender crystals high relief 2 cleavage directions mod to strong birefringence parallel inclined symmetric

Answer 241

amphibole

Question 242

mg fe amphiboles

Answer 242

antophyllite-cummingtonite-grunerite

Question 243

ca fe mg amphiboles

Answer 243

tremolite-actinolite-hornblende

Question 244

sodic amphiboles

Answer 244

glaucophane-ribeckite-arvedsonite

Question 245

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

Answer 245

biotite

Question 246

minute crystals usually tabular or prismatic habit and birefringent

Answer 246

microllites

Question 247

smaller spherical rod like and hair like isotropic forms

Answer 247

crystallites

Question 248

an aphanitic or glassy texture that are completely free of phenocrysts

Answer 248

aphyric

Question 249

some are euhedral subhedral rest are anhedral

Answer 249

granitic structure

Question 250

all are anhedral

Answer 250

aplitic texture

Question 251

phenocrysts are gathered distinct clusters

Answer 251

glomeroporphyritic

Question 252

monomineralic clusters in a glomeroporphyritic texture

Answer 252

glomerocrysts

Question 253

polyminerallic clusters in a glomeroporphyritic texture

Answer 253

cumulocrysts

Question 254

continuous ranges of size in crystals of the principal minerals in a fine grained matrix

Answer 254

seriate

Question 255

broken series of sizes

Answer 255

hiatal

Question 256

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

Answer 256

poikolitic

Question 257

randomly arranged plagioclase chadacrysts are elongate and ate wholly poikolophitic enclosed by the augite oikocryst

Answer 257

ophitic

Question 258

glass occupies wedge shaped interstices between plan laths

Answer 258

intersertal

Question 259

spaces between plag laths are occupied by one or more grains of pyroxene olivine or opaque minerals

Answer 259

intergranular

Question 260

other term for euhedral

Answer 260

idiomorphic automorphic

Question 261

other term for subhedral

Answer 261

hypidiomorphic hypoautomorphic

Question 262

other term for anhedral

Answer 262

xenomorphic allotriomorphic

Question 263

subparallel arrangement of microcystalline lath shaped feldspars in groundmass

Answer 263

trachytic

Question 264

trachytic texture with crystalline material in between feldspars

Answer 264

pilotaxitic

Question 265

trachytic texture with cglassy material in between feldspars

Answer 265

hyalopilitic

Question 266

subparallel arrangement of tabular bladed or prismatic crystals which are visible to the naked eye

Answer 266

trachitoid

Question 267

dense holocrystalline tightly appressed microlites generally of feldspars interwoven in irregular unoriented fashion

Answer 267

felty

Question 268

boundary involves interdigitations

Answer 268

consertal

Question 269

form a eutectic mixture or through replacements similar to cuneiform writing

Answer 269

graphic

Question 270

patches of plag felds intergrown with vermicular qtz

Answer 270

mermyktic texture

Question 271

intimate intergrowth of 2 minerals in which one mineral has a vermicular

Answer 271

symplectite texture

Question 272

composed of an aggregate of fibtrous crystals radiating from a nucleus with glass or crystals in between

Answer 272

spherulitic

Question 273

radiate texture with radiating fibers extending from either end if linear nucleus rahter than a point

Answer 273

axiolitic

Question 274

radiate texture with fanlike arrangement of divergent often branching fibers

Answer 274

variolitic

Question 275

crystal of one mineral is surrounded by a rim or mantle of one or more crystals of another mineral

Answer 275

corona

Question 276

corona texture charac by an overgrowth by NA plag on large K felds

Answer 276

rapakivi

Question 277

charac by an overgrowth of pyroxene of hornblende or olivine or garnet

Answer 277

kelyphitic

Question 278

one or more concentric bands ina single crystal are picked out by lines of inclusions or by gradual or abrupt changes in solid solution

Answer 278

zoning

Question 279

charac having dips or bay like section in thte crystals as a result of resorption disequilibrium

Answer 279

embayed

Question 280

how many space groups are determined?

Answer 280

230 space groups

Question 281

4-faced form where the faces are related by mirror planes

Answer 281

Rhombic Pyramid

Question 282

4-faced form where the faces are related by a 4 axis

Answer 282

Tetragonal Pyramid

Question 283

8-faced form where all faces are related by a 4 axis.

Answer 283

Ditetragonal Pyramid

Question 284

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

Answer 284

Dihexagonal Pyramid

Question 285

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

Answer 285

Dipyrami

Question 286

are closed 6, 8, or 12 faced forms, with 3, 4, or 6 upper faces offset from 3, 4, or 6 lower faces.

Answer 286

Trapezohedrons

Question 287

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

Answer 287

Scalenohedrons

Question 288

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.

Answer 288

Rhombohedrons

Question 289

closed form consisting of 4 faces. These are only present in the orthorhombic system (class 222) and the tetragonal system (class )

Answer 289

Disphenoids

Question 290

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.

Answer 290

Hexahedron

Question 291

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).

Answer 291

Octahedron

Question 292

12-faced form. Dodecahedrons can be formed by cutting off the edges of a cube. The form symbol for a dodecahedron is {110}.

Answer 292

Dodecahedron

Question 293

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

Answer 293

Trapezohedron

Question 294

occur as accessory minerals in igneous and metamorphic rocks and as resistant detrital grains in sediments

Answer 294

Oxides

Question 295

Includes the majority of ore minerals

Answer 295

Sulfides

Question 296

adjacent silica tetrahedra share oxygens to form the different types of silicates

Answer 296

polymerization

Question 297

describes the phenomena of polarization, reflection, refraction and interference, which form the basis for optical mineralogy

Answer 297

Wave theory

Question 298

In isotropic materials the Wave Normal and Light Ray are?

Answer 298

parallel

Question 299

A measure of how effective a material is in bending light is called

Answer 299

Index of Refraction (n)

Question 300

used to calculate how much the light will bend on travelling into the new medium

Answer 300

Snell's law

Question 301

in which minerals are seen with pleochroism?

Answer 301

tourmaline, biotite, hornblende, (most amphiboles), some pyroxenes.

Question 302

The ability to selectively transmit and absorb light is termed

Answer 302

pleochroism

Question 303

involves the determination of the refractive index of minerals, using the immersion method.

Answer 303

Refractometry

Question 304

This method relies on having immersion oils of known refractive index and comparing the unknown mineral to the oil.

Answer 304

Refractometry

Question 305

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

Answer 305

Relief

Question 306

the indices of the mineral and surrounding medium differ by greater than 0.12 RI units.

Answer 306

Strong relief

Question 307

indices differ by 0.04 to 0.12 RI units

Answer 307

Moderate relief

Question 308

Indices differ by or are within 0.04 RI units of each other

Answer 308

Low relief

Question 309

what is the index of oil

Answer 309

1.45

Question 310

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.

Answer 310

Becke Line

Question 311

exhibits parallel extinction inclined symmetrical

Answer 311

orthopyroxene biotite Clinopyroxene, Hornblende amphibole; calcite

Question 312

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)

Answer 312

Gypsum Plate

Question 313

Retardation of 147 nm, the interference colour is a first order white

Answer 313

Mica Plate

Question 314

Wedge shaped and produces a range of retardations

Answer 314

Quartz sWedge

Question 315

the overall total retardation is less than that exhibited by the mineral prior to the accessory plate being inserted.

Answer 315

negative elongation

Question 316

the total overall retardation is greater than that exhibited prior to the accessory plate being inserted

Answer 316

- POSITIVE ELONGATION,

Question 317

Minerals which display moderate to strong birefringence may display a change in relief as the stage is rotated, in plane light.

Answer 317

Relief

Question 318

coloured anisotropic minerals display a change in colour

Answer 318

pleochroism or diachroism

Question 319

form when the vibration directions in the interference figure parallel the vibration directions of the polars. These are areas of extinction

Answer 319

Isogyres

Question 320

breaking up of the white light

Answer 320

Dispersion

Question 321

Plane-Polarized (PPL) Properties

Answer 321

Color - Pleochroism - Habit - Cleavage and Fracture - Relief - Index of Refraction

Question 322

Cross-Polarized (XPL) Properties

Answer 322

Birefrringence - Extinction - Sign of Elongation - Twinning and Zoning

Question 323

This property is present when areas with differing extinction orientations within the same mineral grain have planar contacts.

Answer 323

Twinning

Question 324

polarizing transmitted-light microscope, commonly known as

Answer 324

petrographic microscope

Question 325

typical bulb used has a tungsten filament, which gives the field view a yellowish tint.

Answer 325

The Light Source

Question 326

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

Answer 326

field diaphragm

Question 327

closed to increase resolution, it can be seen when the Bertrand’s lens is inserted

Answer 327

aperture diaphragm

Question 328

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

Answer 328

Condenser and Convergent Lens

Question 329

marked in degree units and a side vernier enables angles of rotation to be accurately measured

Answer 329

Stage

Question 330

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

Answer 330

Objectives

Question 331

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

Answer 331

The Bertrand Lens

Question 332

The slot is oriented so that accessory plates are inserted at 45o to the cross wires. In some microscopes the slot may be rotatable

Answer 332

The Accessory Slot

Question 333

what is the grit called

Answer 333

carborundum grit

Question 334

standard thickness

Answer 334

30 microns

Question 335

30 microns

Answer 335

Buffing

Question 336

> 66 wt. %

Answer 336

Felsic

Question 337

52 – 66 wt. % SILICA

Answer 337

Intermediate

Question 338

45 – 52 wt. % silica

Answer 338

Mafic

Question 339

silica content < 45 wt. %

Answer 339

Ultramafic

Question 340

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

Answer 340

Aphanitic

Question 341

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

Answer 341

Pegmatitic

Question 342

plutonic igneous rocks, which underwent slow crystallization underneath the surface of the earth

Answer 342

Phaneritic

Question 343

can also form when magma is crystallized under a volcano but eruption occurs before the crystallization is complete.

Answer 343

porphyritic texture

Question 344

low silica and gas contents make them very fluid; i.e., they have a low viscosity, or resistance to flow

Answer 344

Classification of Ultramafic Intrusive Rocks Classification of Pyroclastic Rocks Ultramafic Rocks

Question 345

intrusive ultramafic rocks,

Answer 345

peridotite

Question 346

extrusive ultramafic rocks.

Answer 346

komatiite

Question 347

Rocks composed mostly of pyroxene, calcium-rich plagioclase, and minor amounts of olivine

Answer 347

Mafic Rocks

Question 348

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

Answer 348

Intermediate Rocks

Question 349

similar to pumice but usually made of iron rich minerals found in basalt lava

Answer 349

cinders (scoria)

Question 350

mafic crystals of felsic intermediate mafic ultramafic

Answer 350

1-15% 16-45% 46-85% >85%

Question 351

occurs between diagenesis and melting

Answer 351

Metamorphism

Question 352

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

Answer 352

metamorphic facies

Question 353

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

Answer 353

Metasomatism

Question 354

when the T-P increases on a body of rock

Answer 354

Prograde metamorphism

Question 355

T-P fall due to erosion of overlying rock or due to tectonic uplift

Answer 355

Retrograde metamorphism

Question 356

Pressure increases with depth due to the weight of the overlying bedrocks

Answer 356

lithostatic pressure

Question 357

orce acting equally from all directions, it is a type of stress called hydrostatic stress, or uniform stress.

Answer 357

Pressure

Question 358

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

Answer 358

Contact Metamorphism

Question 359

Rock in the deep portions of faults undergoes dynamic metamorphism and creates a fine grained metamorphic rock called

Answer 359

mylonite

Question 360

referred to as shock quartz

Answer 360

coesite or stishovite

Question 361

Started out originally with clay minerals and as a result of metamorphism, alumna rich minerals form

Answer 361

Pelitic

Question 362

The clay minerals have recrystallized into tiny micas which reflect a glossy luster

Answer 362

Phyllite

Question 363

The rock developed a near planar foliation caused by the preferred orientation of sheet silicates. However, quartz and feldspar grains show no preferred orientation

Answer 363

Schist

Question 364

irregular planar foliation

Answer 364

schistosity

Question 365

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

Answer 365

pophyroblasts

Question 366

dark colored minerals tend to become segregated in distinct bands through the rock, giving the rock

Answer 366

gneissic banding

Question 367

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

Answer 367

granulite

Question 368

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

Answer 368

Migmatites

Question 369

Usually poorly foliated and form at intermediate to high grades of metamorphism of basaltic or gabbroic protoliths

Answer 369

Amphibolite

Question 370

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.

Answer 370

Hornfels

Question 371

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

Answer 371

Zeolite Facies and Prehnite-Pumpellyite Facies

Question 372

what are the Intermediate Pressure Facies

Answer 372

Zeolite Facies and Prehnite-Pumpellyite Facies Greenschist facies Amphibolite facie Granulite facies

Question 373

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

Answer 373

Metavolcanics and greywackes

Question 374

Musc + Chl + Ab + Qtz (indistinguishable from greenschist facies)

Answer 374

Metapelitic rocks

Question 375

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

Answer 375

Metabasic rocks (Greenschist facies)

Question 376

* Dolomite + Qtz

Answer 376

Siliceous dolomites (Greenschist facies)

Question 377

Hbl + Pl ± Ep, garnet, cummingtonite, diopside, Bt

Answer 377

Metabasic rocks (Amphibolite facies)

Question 378

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.)

Answer 378

Metapelitic rocks (Amphibolite facies)

Question 379

Forms under conditions of P(H2O)

Answer 379

Granulite facies

Question 380

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)

Answer 380

Metabasic rocks (Granulite facies)

Question 381

what are the High Pressure Facies

Answer 381

Blueschist Facies. Eclogite Facies

Question 382

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.

Answer 382

Blueschist Facies

Question 383

glaucophane + Law + Chl ± phengite/paragonite, omphacite * Metagreywackes * Qtz + jadeite + lawsonite ± phengite, glaucophane, Chl

Answer 383

Metabasic rocks (Blueschist Facies )

Question 384

phengite + paragonite + carpholite + Chl + Qtz

Answer 384

Metapelites (Blueschist Facies)

Question 385

Aragonite

Answer 385

Carbonate rocks (Blueschist Facies)

Question 386

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

Answer 386

Eclogite Facies

Question 387

omphacite + garnet ± kyanite, Qtz, Hbl, zoisite

Answer 387

Metabasic rocks (eclogite facies)

Question 388

Qtz + phengite + jadeite/omphacite + garnet

Answer 388

Meta-granodiorite (eclogite facies)

Question 389

phengite + garnet + kyanite + chloritoid (Mg-rich) + Qtz * phengite + kyanite + talc + Qtz ± jadeite

Answer 389

Metapelites (eclogite facies)

Question 390

what are the Low Pressure Facies

Answer 390

Albite-Epidote Hornfels Facies Hornblende Hornfels Facies Pyroxene Hornfels Facies Sanidinite Facies

Question 391

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.

Answer 391

Albite-Epidote Hornfels Facies

Question 392

Ab + Ep + actinolite + Chl + Qtz * Metapelites * Musc + Bt + Chl + Qtz

Answer 392

Metabasic rocks (Albite-Epidote Hornfels Facies)

Question 393

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

Answer 393

Hornblende Hornfels Facies

Question 394

Hbl + Pl ± diopside, anthophyllite/cummingtonite, Qtz

Answer 394

Metabasic rocks Hornblende Hornfels Facies

Question 395

Musc + Bt + andalusite + cordierite + Qtz + Pl

Answer 395

Metapelites Hornblende Hornfels Facies

Question 396

cordierite + anthophyllite + Bt + Pl + Qtz

Answer 396

K2O-poor sediments or metavolcanics Hornblende Hornfels Facies

Question 397

same as amphibolite facies

Answer 397

Siliceous dolomites Hornblende Hornfels Facies

Question 398

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.

Answer 398

Pyroxene Hornfels Facies

Question 399

* Opx + Cpx + Pl ± Ol or Qtz

Answer 399

Metabasic rocks Pyroxene Hornfels Facies

Question 400

* cordierite + Qtz + sillimanite + Kfeldspar (orthoclase) ± Bt * cordierite + Opx + Pl ± garnet, Sp

Answer 400

Metapelites Pyroxene Hornfels Facies

Question 401

calcite + Fo ± diopside, periclase * diopside + grossularite + wollastonite ± vesuvianite

Answer 401

Calcareous rocks Pyroxene Hornfels Facies

Question 402

Rarely found, as the extremely high temperatures required are only achieved at direct contacts with flowing basic magma, or in completely-immersed xenoliths

Answer 402

Sanidinite Facies

Question 403

cordierite + mullite + sanidine + tridymite (often inverted to Qtz) + glass

Answer 403

Metapelitic rocks Sanidinite Facies

Question 404

* wollastonite + An + diopside * monticellite + melilite ± calcite, diopside * alsotilleyite, spurrite, merwinite, larnite and other rare Ca- or CaMg silicate

Answer 404

Calcareous rocks Sanidinite Facies

Question 405

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

Answer 405

Boles and Coombs

Question 406

Mafic Assemblages at Low Grades

Answer 406

Zeolite and prehnite-pumpellyite facies

Question 407

Mafic Assemblages of the Medium P/T Series

Answer 407

Greenschist, Amphibolite, and Granulite Facies

Question 408

constitute the most common facies series of regional metamorphism

Answer 408

greenschist, amphibolites and granulite facies

Question 409

classical Barrovian series of pelitic zones and the lower-pressure BuchanAbukuma series are variations on this trend

Answer 409

Mafic Assemblages of the Medium P/T Series

Question 410

Metamorphism of mafic rocks first evident

Answer 410

greenschist facies, which correlates with the chlorite and biotite zones of associated pelitic rock

Question 411

impart the green color form which the mafic rocks and facies get their name

Answer 411

Chlorite, actinolite, and epidote

Question 412

Amphibolite facies transition involves two major mineralogical changes 1. Albite→ oligoclase 2. Actinolite→ hornblende(amphibole accepts increasing aluminum and alkalis at higher T)

Answer 412

Greenschist

Question 413

Mafic Assemblages of the Low P/T Series

Answer 413

Albite-Epidote Hornfels, Hornblende Hornfels, Pyroxene Hornfels, and Sanidinite Facies

Question 414

Albite-epidote hornfels facies correlates with the greenschist facies into which it grades with increasing pressure

Answer 414

Hornblende hornfels facies correlates with the amphibolite facies, and the pyroxene hornfels and sanidinite facies correlate with the granulite facies

Question 415

Mafic Assemblages of the High P/T Series The association of glaucophane + lawsonite is diagnostic

Answer 415

Blueschist and Eclogite Facies

Question 416

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)

Answer 416

blueschist facies

Question 417

stable to lower pressures, and may extend into transitional zones

Answer 417

Crossite

Question 418

breaks down at high pressure by reaction to jadeitic pyroxene + quartz:

Answer 418

Albite

Question 419

Unstable minerals

Answer 419

pyroxenes, olivines, amphiboles, some plagioclase feldspars

Question 420

Stable minerals

Answer 420

quartz, K-feldspar, Na- feldspar, muscovite, clay minerals, some 'heavy minerals'

Question 421

(transported to the site of deposition

Answer 421

allogenic example: Framework grains and matrix

Question 422

precipitated at the site of deposition

Answer 422

authigenic cements

Question 423

Preferential orientation of particles in a sediment or tendency of a rock to break in specific directions

Answer 423

Fabric

Question 424

cemented by minerals precipitated in pore spaces breccia and conglomerate

Answer 424

✓ Silica (quartz) ✓ Carbonate (calcite) ✓ Ferruginous (Fe-oxides)

Question 425

Common cements

Answer 425

calcite, hematite, quartz, and clay

Question 426

Common association on glacial till and debris flow deposits

Answer 426

Paraconglomerate

Question 427

Flat-pebble conglomerates formed by mud rip-ups

Answer 427

Intraformational (within basin)

Question 428

More likely to be petromictic

Answer 428

Extraformational (outside basin)

Question 429

Three components of a rock:

Answer 429

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

Question 430

high textural maturity, grain-supported fabric, grains held together by chemically precipitated cement.

Answer 430

< 15% matrix - arenites

Question 431

15%-75% matrix

Answer 431

wackes: dirty, low textural maturity, largely matrixsupported fabric

Question 432

The degree of mineralogical maturity can be determined by looking at the types of grains present

Answer 432

contains no feldspar (feldspar easily weathers to clay)

Question 433

Presence of fresh, large, angular feldspar fragments in a sandstone imply

Answer 433

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)

Question 434

Small, rounded, highly weathered feldspars imply:

Answer 434

a. a low relief source area and/or warm, humid climate (modernintense weathering processe

Question 435

Absence of feldspars imply

Answer 435

a. intense weathering (destroying feldspars) OR no feldspars in original source

Question 436

rock fragments are chiefly of shale or slate

Answer 436

Phyllarenite

Question 437

where the rock fragments are of limestone

Answer 437

Calcilithite

Question 438

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.

Answer 438

Arkoses

Question 439

chiefly of mudrock and their low grade metamorphic equivalents and volcanic grains

Answer 439

Lithics

Question 440

fluvial and deltaic sandstones Immature composition implies high rates of sediment production followed by short transport distances

Answer 440

Litharenites

Question 441

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

Answer 441

Greywackes

Question 442

oscillatory (microscale) zoning: volcanic or hypabyssal origin - progressive (coarse) zoning: igneous source, undifferentiated

Answer 442

Plagioclase Zoning

Question 443

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

Answer 443

MUDROCKS

Question 444

calcareous mudrocks

Answer 444

Marls

Question 445

<4µm; Silt - 4 to 62 µm

Answer 445

Clay -

Question 446

usu. laminated and fissile.

Answer 446

Shale

Question 447

used for a more indurated mudrock

Answer 447

Argillite

Question 448

Absent when sediments are bioturbated, presence of much qtz silt or calcite, flocculation of clays during sedimentation

Answer 448

Fissility

Question 449

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

Answer 449

Lamination

Question 450

The simplest phyllosilicates result from bonding one silicate layer to one octahedral layer. Because of this arrangement, we call these the 1:1 phyllosilicates

Answer 450

Phyllosilicate Structures

Question 451

Montmorillonite and beidellite result from the alteration of volcanic ash to give bentonite clay deposits

Answer 451

Montmorillonite Group (Smectites) Clay Minerals

Question 452

the most common clay mineral in sedimentary rocks

Answer 452

. Illite

Question 453

Montmorillonite Group 2:1

Answer 453

Illite Chlorite

Question 454

dominant in low-latitude areas, particularly off major rivers draining regions of tropical weathering. most important 1:1 phyllosilicate

Answer 454

Kaolinite

Question 455

more common in ocean-floor muds of higher latitudes.

Answer 455

Illite

Question 456

related to active mid-ocean ridge systems and volcanic oceanic islands

Answer 456

Smectites

Question 457

25% of all sedimentary rocks ✓ Present from the pre-cambrian onward

Answer 457

Carbonate Rocks Pre-cambrian Carbonates – almost all dolomite - Tertiary Carbonates – very little dolomite

Question 458

Carbonate Requirements

Answer 458

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

Question 459

Orthorhombic Crystal - Hardness of 4

Answer 459

Aragonite

Question 460

Hexagonal (rhombohedral crystal) ▪ Hardness of 3

Answer 460

been dominant skeletal material in during the Paleozoic

Question 461

Siderite – (FeCO3) * Magnesite – (MgCO3) * Rhodochrosite – (MnCO3)

Answer 461

Dolomite – CaMg(CO3)2

Question 462

– fecal material excreted by benthic organisms

Answer 462

Peloids

Question 463

These are exoskeletons or benthic (bottom-dwelling), mobile and sessile (esp. attached) organisms

Answer 463

Gastropods (Snails) * Pelecypods (Clams) * Echinoderms (Sand dollars, Starfish) * Cnidarians (Corals)

Question 464

microgranular in many thinwalled foraminifera but fibrous in larger, thicker species, such as rotaliids, nummulites and orbitolinids.

Answer 464

test wall

Question 465

FORAMINIFERA

Answer 465

Composed of low or high-Mg calcite, rarely of aragonite. - Very diverse in shape but common forms are circular to subcircular w/ chambers.

Question 466

(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

Answer 466

Coccolithophorids

Question 467

other term for Coccolithophorids

Answer 467

Chrysophyta

Question 468

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.

Answer 468

. Micrite

Question 469

large crystals of Lo-Mg calcite that from cement in limestones

Answer 469

Sparry calcite

Question 470

photic zone

Answer 470

(generally 0-30 m) is the most productive site for carbonate sediments, the socalled carbonate factor

Question 471

year of folks

Answer 471

1959 1962

Question 472

limestone formed in situ such as a stromatolite or reef-rock;

Answer 472

biolithite-

Question 473

micrite w/ cavities such as birds-eye limestone

Answer 473

dismicrite

Question 474

general term for fine-grained siliceous sediments of chemical, biochemical or biogenic origin.

Answer 474

Chert

Question 475

for chert nodules occurring in Cretaceous chalks

Answer 475

Flint

Question 476

fine-grained siliceous rocks w/ a texture and fracture similar to unglazed porcelain; also used for an opaline claystone composed largely of opal-C

Answer 476

Porcellanite

Question 477

Three major groups of organisms that build their skeletons of silica:

Answer 477

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

Question 478

also referred to as drusy quartz as it commonly occurs as a pore- filling cement

Answer 478

megaquartz

Question 479

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

Answer 479

chalcedonic quartz

Question 480

defined as sediments with > 15-20% P2O5; a source of fertilizer

Answer 480

Phosphatic Sediments

Question 481

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

Answer 481

Phosphorites

Question 482

deposits of organic material (mainly from phytoplanktons) in marine basins and lakes

Answer 482

Sapropels

Question 483

forms during the accumulation of plant remains in anaerobic, watersaturated environment, generally in fresh water swamps and bogs in cool climates

Answer 483

peat

Question 484

vascular (land) plant derived organic compounds altered by elevated temperature and burial pressure

Answer 484

Humic coal

Question 485

Formed from non-vascular (algal) plant material

Answer 485

Sapropelic coal

Question 486

sylvinite: mixture of sylvite, carnallite and halite -- fertilizer

Answer 486

potash

Question 487

metastable; not preserved in rocks older than miTertiary; readily devitrified and replaced during weathering and diagenesis

Answer 487

Volcanic glass

Question 488

smectite rich clay beds derived from the alteration of volcanic ash

Answer 488

Bentonite

Question 489

hydrous sodium calcium aluminum silicates; formed from alteration volcanic glass, usually cryptocrystalline; often develop when ash has fallen into alkaline lakes

Answer 489

Zeolites

Question 490

generally refers to beds thicker than 10 mm

Answer 490

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)

Question 491

generally refers to beds thinner than 10 mm

Answer 491

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)

Question 492

(= ichnofossils = lebensspuren): traces of organism (commonly animal) activities and behavior (dwelling, feeding, locomotion, resting), not actual body fossils.

Answer 492

Trace fossils

Question 493

MINERAL RESOURCES FROM SEDIMENTS

Answer 493

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)

Question 494

groundmass is made up rectangular formed feldspar instead of lath slender lath crystals

Answer 494

orthopyric

Question 495

phenocrysts in a porphyritic texture are clustered into aggregates called glomerocrysts or crystals clots which indicates crystal fractionation by crystal settling

Answer 495

glomeroporphyritic

Question 496

phenocrysts contain small grains of other minerals enclosing them indicating that the smaller grains may have crystallized first

Answer 496

poikilitic

Question 497

variety of poikilitic texture where plag laths are enclosed by pyroxenes or olivine

Answer 497

ophitic

Question 498

variety of ophitic wherein plag encloses ferromagnesian minerals indicating slower cooling in basaltic rocks

Answer 498

subophitic

Question 499

also called corona reaction rim and rapakivi displays a secondary mineral formed around another mineral indicating a post magmatic reaction

Answer 499

opacitic

Question 500

variety of opacitic where there is a secondary rim or corona

Answer 500

kelyphitic

Question 501

occurs where crystal occupies occupy spaces between at least two larger crystals indicating a later formation

Answer 501

intergranular

Question 502

denotes that angular spaces between crystals are filled with glass that may be devitrified or altered and small crystals

Answer 502

intersertal

Question 503

holocrystalline groundmass with lath shaped microlites typically pla are generally oriented irregularly

Answer 503

pilotaxitic

Question 504

extrusive igneous rock texture wherein the groundmass flow in the direction of lava flow and around inclusions and occurs in alkali rich rocks

Answer 504

trachytic

Question 505

microscopic variety of trachytic that is visible to the naked eye

Answer 505

trachytoid

Question 506

also called symplectic is an intergrowth of branching rods of quartz set in a single crystal of plag

Answer 506

myrmekitic

Question 507

intergrowth of plag feldspar in alkali feldspar host

Answer 507

perthitic

Question 508

intergrowth of alkali feldspar in plag feldspar host

Answer 508

holocrystalline

Question 509

mix of glass and crystals but contains more crystals than glass

Answer 509

hypohyaline

Question 510

contains 100% glass

Answer 510

holohyaline

Question 511

contains very coarse grains having >30mm in diameter

Answer 511

pegmatitic

Question 512

displays grains that are generally equant

Answer 512

granular

Question 513

medium to coarse grained minerals most of which are devoid of crystal faces

Answer 513

granitic

Question 514

contains equidimensional cryptocrystalline groundmass

Answer 514

felsitic

Question 515

variety of poikilitic where in inclusions have a complete series of crystal sizes

Answer 515

seriate

Question 516

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

Answer 516

decompression

Question 517

lowering of the melting temperature of the mantle due to the presence of fluxes causing earlier melting and production of the magma

Answer 517

flux melting

Question 518

who devised the way of measuring the relative size or magnitude of volcanic eruptions ?

Answer 518

The Volcano Explositivity Index Newhall, C. and Self S. in 1982

Question 519

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

Answer 519

phreatic

Question 520

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

Answer 520

phreatomagmatic

Question 521

effusive eruptions that produce large volumes of very hot thin runny lava that extrudes from fissures

Answer 521

icelandic

Question 522

effusive eruptions similar to icelandic eruptions that originates from vents of volcanoes

Answer 522

hawaiian

Question 523

explosive euptions that shoot thicker lava along with a burst of steam gas and ash that spatters molten lava

Answer 523

strombolian

Question 524

series of discrete loud eruptions in throat clearing canon like explosions that shoor high velocity blocks and bombs

Answer 524

vulcanian

Question 525

also called nuee ardente eruptions occur when large amount of tephra gas and lava are erupted laterally from the crated producing glowing avalanches

Answer 525

pelean

Question 526

colossal explosive eruptions that involves very viscous magma and produce very large volumes of ash and tephra that can cover a very wide area

Answer 526

plinian

Question 527

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

Answer 527

pyroclastic cone

Question 528

pyroclastic cones composed predominantly of vesicular basaltic material

Answer 528

scoria cone

Question 529

pyroclastic cones with various compositions

Answer 529

cinder cone

Question 530

volcanoes with an eruptive history that reached VE 8 or stronger

Answer 530

Supervolcano (yellowstone caldera)

Question 531

give examples of extinct volcano, dormant volcano, inactive volcano and potentially active volcano

Answer 531

mt. chimborazo, ecuador mt. kilimanjaro tanzania alligator lake tadlac lake laguna mt. san cristobal laguna

Question 532

short detached vesicle free proximal lava that are often produced by viscous lava such as andesitic and rhyolitic lava

Answer 532

block lava

Question 533

a fractured surface texture formed when bombs cool

Answer 533

breadcrust texture

Question 534

black glassy streamlined particles that formed as lava droplets that quenched in flight

Answer 534

pele's tears

Question 535

golden acicular glassy strands that formed as lava droplets were propelled through the air being partially stretched into shape

Answer 535

pele's hair

Question 536

usually associated with phreatic and pheratomagmatic eruptions and identified to have a pinch and swelling beds with moderate sorting of moderately rounded clasts

Answer 536

pyroclastic surge

Question 537

generally hot flows made up of a mixture of pyroclastic materials and hot gases that can travel at rapid speeds

Answer 537

pyroclastic density currents

Question 538

also known as cognate clasts are derived directly from magma involved in the volcanic activity

Answer 538

juvenile clasts

Question 539

rock inclusions from the vent wall or brought from the surface by lava or pyroclastic walls

Answer 539

accidental clasts

Question 540

fragmentation through explosive ejection and aerial dispersal of pyroclasts of rock and magma from a volcanic vent

Answer 540

autoclastic process

Question 541

fragmentation brought by the weathering and disintegration of volcanic rocks

Answer 541

epiclastic process

Question 542

clasts within the mass flow behaving independently in moving interstitital fluids

Answer 542

traction transport

Question 543

a hot mixture of volcanic debris and tephra that is saturated with water that occurs directly related to an on going eruption

Answer 543

syn eruption lahar

Question 544

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

Answer 544

flood basalt

Question 545

airborne blobs of liquid lava emitted by lava fountaining

Answer 545

spatter

Question 546

also called welded spatter are spatters that solidified at the base of the lava fountain

Answer 546

agglutinate deposits

Question 547

cones produced when welded spatters accumulate around a central vent that can typically grow less than 20m in height

Answer 547

spatter cone

Question 548

linear ridges formed when lave fountains erupt via fissures

Answer 548

spatter ramparts

Question 549

smaller tuff rings

Answer 549

tuff cone

Question 550

glassy volcanic debris and scoria develop die to the explosive eruption of basalt in a water

Answer 550

tuff ring

Question 551

when was PHIVOLCS established

Answer 551

September 17, 1984