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GLE 2024 (Day 2) > SEDIMENTARY PETROLOGY (CLASTIC SEDS) > Flashcards

SEDIMENTARY PETROLOGY (CLASTIC SEDS) Flashcards

1
Q

How much of the seds and seds rocks are Gravelstones or Rudites?

A

5%

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2
Q

Depositional Agent that forms Gravelstones

A

Glaciers and Debris Flows and some water-laid seds

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3
Q

Whats the minimum percentage of Gravel-sized population to be considered as a rudite?

A

at least 30%

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4
Q

Subrounded to rounded, gravel or sand supported, with one composition of clasts

A

Oligomictic Conglo

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5
Q

Subrounded to rounded, gravel or sand supported, with multiple composition of clasts

A

Polymictic Conglo

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6
Q

Subagular to angular, gravel or sand supported, with one composition of clasts

A

Oligomictic Breccia

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7
Q

Subangular to angular, gravel or sand supported, with multiple composition of clasts

A

Polymictic Breccia

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8
Q

Mud-supported Rudites

A

Diamictite

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9
Q

Single composition clast mud supported rudite

A

Oligomictic Diamictite

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10
Q

Angular Clasts

A

Breccia

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11
Q

Rounded Clasts

A

Conglomerate

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12
Q

Single Composition of clast

A

Oligomictic

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13
Q

Multiple compositions of clast

A

Polymictic

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14
Q

What does breccia texture suggest

A

Minimal Transport and nearby provenance

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15
Q

Breccia Environemtns

A

1) Fault zones
2) Talus Slopes due to Rock Falls
3) Impact Craters- Impactities
4) Karst Collapse of Carbonate Rocks
5) Upper portions of Alluvial Fans where Debris Flows are Commons
6) Whereve cohesive mud clasts are eroded and transporte a short distance by streams, currents or gravity flows

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16
Q

Clast-Supported Framwework where clasts are in contact and therefore support one another

A

ORTHOconglomerate/breccia

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17
Q

Orthoconglo-forming environments

A

Principle: Dapat continuous ung travel ng sand and mud or finer particles and napagiwanan ang mga gravel
1) Aqueous envi - Stream Channels, Beaches and Marine Shoals where sand and mud is continuously tranposted while gravel accumulates
2) Alluvial Fans and Ephemeral Braided Rivers Stream in which fines are removed and settled as SIEVE DEPOSITS
3) In areas where sands are entrained by winds from the surface leaving Gravel as LAG DEPOSITS

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18
Q

A matrix supported rudite with the matrix composed mostly of sand

A

Sand-Supported

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19
Q

Environments of a sand Supported Rudite

A

Principle: Dapat pwedeng mag accumulate together si Sand and Gravel
1) Alluvial Fans
2) River Channels, Braid Bars, Point Bars
3) Beaches, Marine Shoals, Storm Deposits
4) High conc sed gravity flows

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20
Q

Mud-supported Matrix

A

Diamictite or Paraconglomerate

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21
Q

Environments of Mud-Supported/Diamictites/Paraconglo

A

1) Glaciers - Tillites (Gravel + mud rich till)
2) Mudflows and Debris Flows including Lahars
3) Gravel-bearing sed gravity flows deposited in mud rich areas
4) tectonic Melanges at Covergent Plate Boundaries

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22
Q

Typical Composition of Oligomictic

A

Compositionally/Mineralogically Mature and so Quartz Rich

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23
Q

Specific examples of Oligomictic Breccias

A

Fault, Collapse and Rockfall Breccias

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24
Q

What infor can Polymictic conglo give?

A

Significant and easily accessible info concerning the nature of the rocks in the source areas

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25
Q

Info that a Rudite with large clasts can provide

A

1) Provenance infor source Rocks
2) Climate and Relief
3) duration and intensity of Transport
4) Tectonic Settings

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26
Q

A conglo with preserved unaltered rocks implies that

A

1) Clasts are highly durable and chemically stable (Quartz-rich)
2) Low Precipitation and Temp w/c inhibit chem decompostions
3) High Relief and Low Vegetative cover w/c promote rapid erosion and minimize duration of chemical decomposition and clast disintegration
4) Short Tranpo w/c promotes survival of mechaically unstable clasts

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27
Q

PLUTONIC CLASTS imply that

A

A relatively nearby source area

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28
Q

Presence of mafic fragments implies that

A

High Relief
Rapid Erosio
LowrT and Rainfall

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29
Q

Granitoid Rock Fragments are commonly derived from

A

Intracratonic Rift Settings
Magmatic Arc

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30
Q

What is the implication of Limestone-and-evaporite rich Conglo

A

Source area as high relief and high erossion rate and low T and Rainfall

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31
Q

Clasts are both rounded and angular

A

Breccio-Conglomerate

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32
Q

Direct deposits of melting ice by glaciers

A

Till or Tillites (Lithified Rock)

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33
Q

non-glacial til like deposits (Olistostrome or graiflow)

A

Tilloid

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34
Q

Sed chaotic deposits of intimately mixed heterogenous materials w/c accumulate as SEMIFLUID body by submarine gravity sliding or slumping of unconsolidated seds

A

Olistostrome

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35
Q

Percentage of matrix to be considered Orthoconglo/Clast supported

A

<15%

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36
Q

Clast supported with no matrix at all

A

Open Framework

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37
Q

Clast suppored with finer sed matrix

A

Closed Framework

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38
Q

more thant 90% of the clasts consist only of resistant rocks ad mienrals such as metaquartzite, vein quartz and chert and are usually formed in environemtns which promote chemical decomposition (Low Relief, not rapid transport, babad ang seds,) like stream channels, bar deposits, near shore marine settings

A

Oligomict

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39
Q

Clasts of many different composition of metable stable and ustable rocks and are more abundant than the former ad is mostly formed in High Relief Areas

A

Petromict

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40
Q

Boundary between Matrix supported Conglo and sand or mudstone

A

> 50% fines

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41
Q

Clasts same material as the matrix ad was formed as a result of REWORKING of lithified sediment soon after deposition derived from Interior (Intrabasinal sources)

A

Intraformational Conglomerate

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42
Q

A conglo in which clasts are exotic and are normally well rounded and well sorted since the source rock are distant from the depositional area

A

Extraformational Conglomerate

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43
Q

Rocks that contain less thant 30% Gravel and >1:1 Sand to mud ratio

A

Sandstones

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44
Q

Folks Classification

A

Isang Triangle with Seven Divisons beased on %Q, %F , and %LF

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45
Q

Sandstone w/ 95% Q in Folks

A

Qtzarenite

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46
Q

75-95% Q, >1:1 F:L

A

Sub arkose

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47
Q

75-95% Q, <1:1 F:L

A

Sublitharenite

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48
Q

<75% Q, >3:1 F:L

A

Arkoses

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49
Q

<75% Q, <1:3 F:L

A

Litharenites

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50
Q

<75% Q, between 1:1 to 3:1 F:L

A

Lithic Arkose

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51
Q

<75% Q, between 1:1 to 1:3 F:L

A

Feldsphatic Litharenites

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52
Q

Sandstones with significant mud matrix

A

Wackes

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53
Q

Sandstones with neglibile matrix

A

Arenites

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54
Q

Pettijohn’s Classification

A

May Percent matrix na kasama aside from QFL and arkosic and lithic arenite lang

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55
Q

How many percet mud matrix <30microns are needed to be considered wackes

A

15%

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56
Q

Boundary between Mudstone and Sandstone

A

75% Mud Matrix Content

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57
Q

95% Q with 15% Mud Matrix

A

Quartz Wacke

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58
Q

<95% w/ >1:1 F:L

A

Feldsphatic Graywacke

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59
Q

<95% w/ <1:1 F:L

A

Lithic Graywacke

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60
Q

A general term for matrix rich sandstones

A

Graywacke

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61
Q

For blatt and tracy, how much is needed to be considered as mudrock?

A

50%

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62
Q

Feldspathic Sandstone

A

Arkoses

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63
Q

Information which can be revealed by Sanstone composition

A
  1. Exposed rock types in source areas
  2. Chemical stability and decompositio history of rock types
  3. Climate, relief, and rates of erosion
  4. Proximity to Source area, and intensity and duration of transport
  5. Tectonic Settings
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64
Q

Tectonic settings in which sediments are derived from arcs over subduction zones along CPBs

A

Magmatic Arcs

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65
Q

Sediments are derived from orogenic mountiain belts which formed at collision plate boundaries

A

Recycled Orogens

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66
Q

Sediments are derived from stable cratonic source rocks from shields, and/or platforms or Continental rift systems

A

Contintental Blocks

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67
Q

Compositional range of Volcanic-Magmatic Arc-derived arenites

A

Litharenites,
Feldsphatic Litharenites,
Lithic arkose

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68
Q

Progressive Erosion of Volcanic-Magmatic Arc Fragments results to a trend of

A

Increasing Q and F, Decrreasing L

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69
Q

Differentiate Young undissected volcanic arc to dissected plutonic arc

A

The former generates a huge number of Aphanitic Rocks fragments while the latter produces Phaneritic Rocks which contain sand size F and Q

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70
Q

Divisions of Recycled Orogen by Dickenson and Suczek

A

1) Subuction Complexes
2) Collision Orogen
3) Foreland Uplifts

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71
Q

Areas which contain Sed rocks, Met rocks and Recycled Volcanic-Magmatic Arc Seds from uplifted recyced Accretionary complexes

A

Subduction Complexes

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72
Q

Contain sed and met rocks of both continental and oceanic origin uplifted during the continental collision that close ocean basins

A

Collision Orogens

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73
Q

Consist of diverse sed, met, and plutonic ign rocks assmeblages exposed in orogenic belts some distance from convergent plate boundaries

A

foreland uplits

74
Q

Sandstones which are situated or formed in orogenic belts

A

Mostly Litharenite, Sublitharenites w/ Subordinate subarkoses and some lithic arkoses

75
Q

Trend in Orogenic Belt Erosion

A

High Q, Low F and L

76
Q

Consists of primarily Precambrian plutonics and high grade met rocks such as granitoids, gneiss and granulite

A

Shields

77
Q

Relatively thin veneer of largely mature detrital sed rocks and or carbonate sed rocks that overlie the shields

A

Platforms

78
Q

Sediments are derived from pre-existing, generally mature, sed rocks that overly plutonic basements (Shields) in a stable platform with VERY LOW RELIEF (PLATFORM ONLY)

A

Craton Interior

79
Q

Both platform sed rocks and plutonic basement shield are exposed as source rock type with LOW to Moderate RELIEF (Shield + Platform w/ Low-Mod Relief)

A

Transitional Cratons

80
Q

Basement Plutons (Shields) are exposed in area of high relief resulting from uplift esp in continental Rift Settings (Shield+High Relief)

A

Uplifted Basements

81
Q

Sandstone which usually form in Cratonic Settings

A

Less Mature Arkoses and subarkise to more mature qtzarenites

82
Q

Trend in Cratonic or Cotinental Block Souce Areas

A

The higher the Relief, The Rapid the erosion, the higher the Felds

The lower the relief the slower the erosion higher chem decomposition, higher qtz content

83
Q

How much of the sed record is constituted by Mudrocks?

A

60-65%

84
Q

Differentiate silt and clay

A

Clay are much smaller and are produced thru decompostion while silt is larger and is mostly formed by disintegration

85
Q

Detrital fractions of mud

A

<30% Gravel
<1:1 S:M

86
Q

Mudrocks with more than 5% gravel

A

Gravelly mudrocks

87
Q

Mudrocks with >1:9 Sand to Mud Ratio

A

Sandy mudrocks

88
Q

Traction transportation

A

Bed load

89
Q

Coarse mudrocks w. >2:1 Silt to mud fraction or more than 2/3s

A

Siltstones

90
Q

Fine mudrocks that contain <1:2 or less than 1/3 silt and more than 2/3s Clay

A

Claystone

91
Q

Constains substantial amts of both clay and silt

A

Mudstone

92
Q

the tendency of certain mudstones and claystones to split into thin layers parallel to the stratification

A

Fissility

93
Q

Fissile Mudstones and Claystones

A

Shale

94
Q

Why is there fissility in Mudstones and Claystones

A

Because there is subparallel alignment of clay and mica minerals

95
Q

Techniques which can be employed to examine mudrocks

A

XRD

96
Q

Decomposition of Ferrogmag in
ALKALINE soils with
LOW DRAINAGE,LOW TEMP in HIGH LATTITUDES

A

Chlorite

97
Q

Product of weathering of ferromag minerals + plagioclase and is favored by impeded drainage in ALKALINE Conditions and SEMIR ARID Climates

A

Smectite (Montmorillonite)

98
Q

weathering of Feldspars especially K-felds common in TEMPERATE REGIONS with NEAR NEUTRAL pH

A

Illite

99
Q

MID LATITUDES SEMI-ARID - TEMPERATE slightly ALKALINE pH

A

Illite-Smectite Mixed Layer

100
Q

Warm, Humid Climate in SUBTROPICS
ACIDIC SOIL
Leaching

A

Degraded Illites
Kandites - Kaolinite

101
Q

Warm and Humid in Tropical Latitudes
Very High Acidity, Low pH
Intense Decomposition of Silica

A

Gibbsite - Bauxite

102
Q

Chlorite

A

High latitudes

103
Q

Kaolinites

A

Low Latitudes

104
Q

Illites, Smectites

A

Common elsewehere

105
Q

Younger Clays

A

Smectite and Mixed Smectite-Illite

106
Q

Older Clays

A

Illite

107
Q

Smectite and Kaolinite alters to

A

Illite and/or chlorite

108
Q

Generally green-colored K-Fe-rich Illite produced in Marine Envi formed by slow precipitation in agitated, oxidizing, marine envi and replacements of fecal pellets in reducing conditions

A

Glauconite

109
Q

Red and Purple mudrocks contains

A

Hematite

110
Q

Ths commonly form in Iron rich mudrocks around decomposing organic matter that reduces iron which results in the removl of red coloration

A

Reduction Spots

111
Q

Yellow to rusty colored contain

A

Limonite

112
Q

Brown Mudrocs have

A

Goethite

113
Q

Meidium to dk gray and black mudrocks ower their color to

A

Presnce of carbon rich organic Material w/ finely divided pyrite

114
Q

Most widely distrbuted sed rocks

A

Mudrocks

115
Q

Mudrock depositional Envi
Magsesettle lang si Mud kapag Calm na ang lahat

A

1) Calm Environments

116
Q

Smectite rich claystones formed by the alteration of volcanic ash deposits generated by explosive eruptions with lumpy popcorn-like appearance since they swell and shrink

A

Bentonites

117
Q

Mudstones that contain sufficient carbon-rich organic material to substantially influence their properties

A

Carbonaceous Mudrocks

118
Q

A carbonaceous mudrock with a black color due to elevated (>2%) of incompletely decomposed, carbon-rich organic matter

A

Black Shales

119
Q

Used to denote organic-rich mudstones and claystone especially by oceanographers and paleoceanographers

A

Sapropel (Organic - Mud)

120
Q

Characterized by Organic mineral content of 15-30% that have potential to yield profitable amounts of petroleum and/or natural gas when heated sufficiently

A

Oil Shales

121
Q

The process of extracting oil and gas by crushing shale (source rock) and heating it in anoxic conditions to 500 deg cel

A

Pyrolysis

122
Q

Bituminous organic material in mudrocks that makes one a source rock

A

Kerogen

123
Q

Oil window for kerogen to be converted to Oil

A

100-140 deg cel

124
Q

Gas Window for kerogen to be converted to Gas

A

160deg cel

125
Q

Factors that favor formation of Carbonaceous mudrocks

A

1)high Bio Prouctivity in the surface water
2) Sluggish Circulatio w/c impedes coarse detritues and oxygen replenishment
3) Anoxic-Reducing Bottom water conditions

126
Q

BOD stands for

A

Biological Oxygen Demand

127
Q

environments favorable for Carbonaecous mudrock formations

A

Lake
Marginal Sea
Epeiric Sea
Deep Ocean Basin

128
Q

Includes all submetamorphic, post depositional changes that affect sediments after accumulation

A

Diagenesis

129
Q

T and P of Diagenesis

A

0-3Kbar
150+/-50 deg cel

130
Q

early shallow diagensis that occurs shortly after burial

A

Eodiagenesis

131
Q

Later, deeper diagenesis

A

MesoDiagenesis

132
Q

Much later, shallow diageneses that occurs as sed rocks approach surface due to erosion

A

Telogenesis

133
Q

Factors Affecting Diagenesis

A

1) Temp (increses at depths)
2) Pressure (increases with depth)
3) Fluid Chemistry (conc of dissolved solids, gases, PH, and Oxidation-reduction potential (Eh)
4) Aqueous fluid circulation rates and patterns w/c depend on porosity, permeability, hdraulic head and rock structure

134
Q

Occurs as a result of increasing confining pressures as sediments are buried progressively deeper beneath the surface

A

Compaction

135
Q

Can act as excellent aquifers or water bearing horizons due to well sorting and retainment of substantial porosity and permeability even after burial

A

Quartzarenite
Arkosic Sandstones

136
Q

Excellent Aquicludes or Aquitards

A

Mudrocks or Siltsones ot Claystones

137
Q

Aquicluide

A

No Flow At all Very Low Hydr. Conductivity

138
Q

Aquitard

A

May allow flow but very slow

139
Q

Are lithic Sandstones and Conglomerates efficient storers and transmitters of fluid?

A

Better than mudorck but much lesser than arkosic sandstones

140
Q

Solubility of minerals increases with increasing

A

pressure

141
Q

Highest stress in a matrix of detrital grains are situated in

A

Point contacts between rigid grains

142
Q

Dissolution caused by increase in pressure within contact points and presence of thin film of water

A

Pressure Solution

143
Q

Pressolution is common in grains of?

A

Quartz Sands and Gravels w/ little to no plastic matrix

144
Q

Long grain contact formed from differential dissolution when 1 grain is more soluble than the other

A

Concavo-Convex

145
Q

Formed when dissoluton rates are equal

A

Straight Contact

146
Q

Differential dissolution is caused by imperfections in the grain contact

A

Sutured Contact

147
Q

occurs when crystalline solids partially or completely dissolve in pore fluids which migrates through fractures and between grains where they may be precipitated as veins and mineral cements

A

Dissolution

148
Q

Occurs when pore fluids precipitate intergranular mineral or mienraloid cements that bind grains together

A

Cementation

149
Q

Major Cements in Detrital Sed Rocks

A

1) Silica
2) Carbonates
3) Iron Oxides and Hydroxides
4) Feldspars
5) Clay Minerals

150
Q

Type of cement overgrowths in which the silica that precipitates intially nucleates on a pre-xiting detrital qtz grain which both go extinct at the same time under the microscope

A

Syntaxial Qtz

151
Q

IN what type of envi is Quartz Cement usually formed

A

Qtzarenite, Gravelstones that accumulated in beach, dune, and shallow marine envi assoc with Intracratonic basins and passive margins

152
Q

An amorphous mineraloids that contains various amounts of water an is a common cement in Volcanoclastic Seds

A

Opal

153
Q

how are opals formed?

A

Silica by product of devitrification of glass shards and pumice to betonties

154
Q

at what T and P are opal cements precipitated

A

Low T and P since Opal Solubility increases with temp and Depth (EODIAGENESIS)

155
Q

Whats the pH conditions in which OPAL tends to form

A

Alkaline (High pH)

156
Q

Cryptocrystalline silica chracterized by microscopic EQUANT Crystals

A

Chert

157
Q

Microcrystalline Silica which are bladed with radiating to Divergent habit under the microscope

A

Chalcedony

158
Q

The most abundant mineral cement

A

Calcite

159
Q

Addition of CO2 though respiration and bacterial decomposition makes pore solutions

A

Acidic (Lowe Ph)

160
Q

Favorable conditions for Calcite precipitation

A

HIGHLY ALKALINE (HIGH Ph) LOW CO2

161
Q

calcite cement composed of one or more cystals that occupy small pore spaces between detrital grains

A

Blocky Cement

162
Q

composed of single, large calcite crystal that nucleates and grows to fill multiple pore spaces that it completely envelops several detrital grains that appear as inclusions (POIKILS) within a single clacite

A

Poikiloptic Cement

163
Q

Iron-rich oxide cements

A

Hematite
Goethite and
Limonite

164
Q

Where does IRON that forms these cements come from?

A

Alteration of Ferromag Silicates during weathering and diagenesis

165
Q

Where is hematite cementation common?

A

Arid Terrestrial Envi
Alluvial fans
Braided Streams
Meandering streamsm flood plains, deserts

166
Q

Rare cement which occur in fedlspar-rich detrtal sed rocks such as arkosic sandstones and gravelstones and apeear as optically clear overgrowths that nucleated on felspar hosts grains (Orthoclase in K felds) (Albite in Plag)

A

Feldspar Cement

167
Q

Type of clay cements which occur as stacks of platy layers called books that precipitate at fairly shallow depths from Low K. acidic pore waters in Terrestrial envi (Eo and Telodiagenesis)

A

Kaolinite cements

168
Q

clay cements which forms at higher temp and depth from high potassium, alkaline ppore waters esp. in Marine Envi (Late Eodiagenesis and Mesodiagenesis)

A

Illite Cement

169
Q

K felds alter to this finegrained mica

A

Sericite

170
Q

Ca and K felds at higher temperatures alter to

A

Albite

171
Q

Volcanic Fragments typically alter to

A

Zeolites

172
Q

Temperature at which mixed layer clay transformed into more ordered Illite

A

200 deg cel

173
Q

Temp at which clay minerals transform into Chlorite and Mica

A

300 deg cel

174
Q

Zeolite minerals stable at below 100 deg cel

A

Analcime and Heulandite

175
Q

Stable from 100-200

A

Laumontite

176
Q

Stable above 200

A

Prehnite - Pumpellyite

177
Q

What are frequently significant Diagenetic Structures in Detrital seds rocks

A

1) Conretions
2) Nodules
3) Geodes
4) Liesegang Rings or Bands

178
Q

Cannonball-like structures Formed by precipitation around a NUCLEATION SURFACE (Fossil, Sand Grain, Shale chip) and which multiple periods can form a concentric structure and a roughly spherhical shape

A

Concretions

179
Q

Similar to concretions but lack a well defined nucleus and generally do not have concentric growth rings which are commonly chert nodules in limesones or dolostones

A

Nodules

180
Q

A nodule with mineral-filed cracks whose origins are still controversial

A

Septarian Nodules

181
Q

Nodules that were or are partly hallow and have roughly spherical to more irregular outer layers of chalcedony and a cavity lined with crystals

A

Geodes

182
Q

Common in many detrital rocks esp. Carbonate or Fe-rich cements bands which are often truncated against prominent joint surfaces and are formed by precipitation by various FeO minerals moving through bodies of rocks separated by fractures from the outside-in that prodcues ring-like patterns of bands

A

Liesegang Rings

GLE 2024 (Day 2) (41 decks)

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