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Title: Clastic Hierarchies


1
Clastic Hierarchies and Eustasy Spring 2005
Professor Christopher G. St. C.
Kendall kendall_at_sc.edu 777.2410
2
Clastic Depositional Systems
  • Their Response
  • to
  • Base Level Change

Based, in part, on classroom lectures by David
Barbeau Chris Kendall
3
Lecture Series Overview
  • Sequence stratigraphy stratigraphic surfaces
  • Basics Ideal sequence of Vail et al 1977
    associated terminology
  • Clastic system response to changing sea level and
    rates of sedimentation - with movie
  • Carbonate systems response to changing sea level
    and rates of sedimentation - with movie
  • Exercises Sequence stratigraphy of carbonates
    and clastics from chronostratigraphy, seismic,
    outcrop and well log character

4
Sedimentary rocks are the product of the
generation, transport, deposition, and diagenesis
of detritus and solutes derived from pre-existing
rocks.
5
Sedimentary rocks are the product of the
creation, transport, deposition, and diagenesis
of detritus and solutes derived from pre-existing
rocks.
6
After Press Siever, 98
7
Depositional Systems
  • depositional system assemblage of multiple
    process-related sedimentary facies assemblages,
    commonly identified by the geography in which
    deposition occurs.
  • EX nearshore depositional system, deep marine
    depositional system, glacial depositional system,
    fluvial depositional system
  • NB depositional systems are
  • modern features
  • used to interpret ancient sedimentary successions

8
Types of Depositional Systems
  • marine ? ocean, sea
  • transitional ? part land, part ocean
  • terrestrial ? land

9
Clastic Depositional Systems
Terrestrial
Transitional
Marine
10
Clastic Depositional Systems
Terrestrial
Transitional
Marine
11
Clastic Depositional Systems
Terrestrial
Transitional
Marine
12
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13
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14
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15
Characteristics of Clastic System
  • Critical stratigraphic signals of system?
  • Geomorphologic tectonic setting
  • Dominant sedimentary processes
  • Facies
  • Subdividing surfaces
  • Lithology
  • Sedimentary structures
  • Geometries Confined versus open
  • Fauna flora

16
Types of Depositional Systems
  • marine ? ocean, sea
  • terrestrial ? land
  • transitional ? part land, part ocean

17
Types of Depositional Systems
  • marine ? ocean, sea
  • transitional ? part land, part ocean
  • terrestrial ? land

18
Marine Depositional Systems
  • shallow/nearshore
  • tide-dominated
  • wave-dominated
  • reef
  • shelf/platform
  • carbonate
  • clastic
  • deep marine
  • deep sea fans
  • pelagic

19
Marine Depositional Systems
  • wave-dominated coasts
  • tide-dominated coasts
  • fluvial-dominated coasts (deltas)
  • carbonate reefs
  • clastic shelves platforms
  • carbonate shelves platforms
  • deepwater fans
  • pelagic abyssal plains

20
Coastal Depositional Systems
  • Form proximal to shorelines
  • Geographically narrow, geologically important
  • Fluid flow transport and deposition
  • Surface waves
  • Tidal waves (not tsunami!)
  • Fluvial input
  • Grain-size decreases with deeper water
  • Onshore, offshore longshore sediment transport
    important
  • Net sediment input (often from rivers) often
    leads to progradational geometries
  • Important for tracking sea-level changes

21
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22
Coast Types
Dalrymple et al, 1992
23
Coast Types
Dalrymple et al, 1992
24
Tidal Range and Coastal Morphology
Hayes, 1979
25
CoastTypes
26
Marine Depositional Systems
  • wave-dominated coasts
  • tide-dominated coasts
  • fluvial-dominated coasts (deltas)
  • carbonate reefs
  • clastic shelves platforms
  • carbonate shelves platforms
  • deepwater fans
  • pelagic abyssal plains

27
Waves Wave Periods
28
Characteristics of Beach Systems
  • Sediments coarsen upward from marine shales
  • Linear sand bodies parallel to basin margin,
    serrated margins landward
  • Formed by a mix of waves and tidal currents
  • Facies
  • Subdivided erosion surfaces formed during
  • Dropping in base level
  • Local channels
  • Rising in base level
  • Wells sorted and rounded pure quartz arenites
    common
  • Sedimentary structures
  • Offshore hummocky wavy bedding
  • Nearshore cut and fill
  • Gently seaward dipping thin parallel beds
  • Geometries
  • Confined incised channels
  • Open linear sheets parallel to shore
  • Fauna flora
  • Marine fauna at base of units
  • Terrestrial flora at crest of units

29
Vertical stacking of shore line sediments
30
CoastTypes
31
Beach Face - South Carolina Foreshore
Note High Energy Planar Beds
Photo G. Voulgaris
32
Trough Cross-bed Current Ripples
Ordovician Near Winchester Kentucky
33
Offshore Coastal Profile - Hummocky
34
Coastal Profile
35
Geomorphologyof Coast
36
Coastal Morphology
37
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38
Coastal Profile and Lithofacies
39
Coastal Lithofacies Architecture
Aigner Reineck, 1982
40
CoastalLithofacies
Reineck Singh, 1980
41
Coastal Lithofacies
Walker, 1984
Progradation
Transgression
Inlet
42
Hayes, 1979
43
Tide Versus Wave Domination
Hubbard et al., 1979
44
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45
Coastal Morphology
46
Wave Dominated - Texan Coast
Note Storm Washover Serrated Back Barrier
47
Wave Dominated - Texan Coast
Note Storm Washover Serrated Back Barrier
48
Wave Dominated - Texan Coast
Note Storm Washover Serrated Back Barrier
49
Wave Dominated - Texan Coast
Note Storm Washover Serrated Back Barrier
50
Note Storm Washover On a Back Barrier
Pennsylvanian Wave Dominated Coast
51
CoastTypes
52
Chenier Coast Gulf of Carpentaria
Note Channels Reworking Chenier Plain
53
Note Channels Reworking Barrier Islands
54
Delta Mouth Bar - Kentucky
Note Incised Surface Of Reworked Bar
55
Tidal, Storm or Tsunami Channel
Note Incised Surface Beneath Channel
56
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57
Characteristics of Sequence Boundary (SB) from
well logs, core outcrop
  • Defined by erosion or incision of underlying
    flooding surfaces (mfs and TS)
  • Inferred from interruption in the lateral
    continuity of these surfaces

58
Characteristics of Sequence Boundary (SB) from
well logs, core outcrop
  • Defined by erosion or incision of underlying
    flooding surfaces (mfs and TS)
  • Inferred from interruption in the lateral
    continuity of these surfaces

59
Beach Ridges St. Phillips Island, SC
60
Progradation Transgressive Architectures
Kraft John, 1979
61
Sea-Level Changes
Reading, 1986
62
Tidal Bundles
Visser, 1980
63
Bedforms Current Ripples
Sand in mud matrix
Sand predominates
Sand Mud 50/50
64
Asymmetric Current Ripples
Upper Mississippian Pennington Formation Pound
Gap
65
Base Level Change on Coast
66
Tidal Geomorphology
Kraft et al, 1987
67
Transitional Depositional Systems
  • Estuaries
  • Deltas

68
Characteristics of Estuary Systems
  • Sediments coarsen upward from marine shales
  • Sand bodies perpendicular to basin margin, narrow
    landward
  • Formed by a mix of tidal currents and occasional
    storm waves
  • Facies
  • Subdivided erosion surfaces formed during
  • Dropping in base level
  • Local channels
  • Rising in base level
  • Wells sorted and rounded pure quartz arenites
    common
  • Sedimentary structures
  • Offshore hummocky wavy bedding
  • Nearshore cut and fill
  • Gently seaward dipping thin parallel beds
  • Geometries
  • Confined incised channels
  • Open linear sheets perpendicular and occasionally
    parallel to shore
  • Fauna flora
  • Marine fauna at base of units
  • Terrestrial flora at crest of units

69
Estuarine Lithofacies
Horne et al, 1978
70
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71
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72
Marine Depositional Systems
  • Wave-dominated coasts
  • Tide-dominated coasts
  • Fluvial-dominated coasts (deltas)
  • Carbonate reefs
  • Clastic shelves platforms
  • Carbonate shelves platforms
  • Deepwater fans
  • Pelagic abyssal plains

73
Deltaic Depositional Systems
  • Form where rivers with large drainages meet
    standing water bodies (basins)
  • Very large sediment flux
  • Fluid gravity flow transport and deposition
  • Surface waves
  • Tidal waves (not tsunami!)
  • Fluvial input
  • Turbidity currents sub-aqueous debris flows
  • Net sediment input often leads to progradational
    geometries
  • Delta types depend on tidal range, wave climate,
    and composition and depths of water in river and
    basin

74
Characteristics of Deltaic Systems
  • Sediments coarsen upward from marine shales
  • Sand bodies form tongues perpendicular to basin
    margin
  • Formed by a mix of fluvial input, tidal currents
    and storm waves
  • Facies
  • Subdivided erosion surfaces formed during
  • Dropping in base level
  • Local channels
  • Rising in base level
  • Poorly sorted and irregular litharenites common
  • Sedimentary structures
  • Offshore laminated to hummocky wavy bedding
  • Nearshore cut and fill
  • Gently seaward dipping thin parallel beds
  • Geometries
  • Confined incised channels
  • Open linear sheets perpendicular and occasionally
    parallel to shore
  • Fauna flora
  • Marine fauna at base of units
  • Terrestrial flora at crest of units

75
Coast Types
Dalrymple et al, 1992
76
CoastTypes
77
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78
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79
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80
Lena River Delta - Russia
81
Shattal ArabDelta
82
Atachafalya Delta - USA
83
Amazon Delta - Brazil
84
Nile Delta - Egypt
85
Delta Types
  • River-dominated
  • Small tidal range, weak storms and large sediment
    flux build delta out into basin
  • Tide-dominated
  • Large tidal ranges dominate transport, deposition
    geomorphology
  • Wave-dominated
  • Strong and repeated storms rework delta sediment

86
Delta Processes
  • Depositional patterns and geomorphology depend on
    the relative dominance of three competing
    processes at river mouths
  • Inertia
  • River water
  • Basin water
  • Friction
  • Water vs. substrate
  • Water vs. water
  • Buoyancy

87
Delta Processes
  • Relative influence of inertia, friction
    buoyancy is a function of
  • Density contrasts
  • Homopycnal flow equal density water bodies mix
  • Hyperpycnal flow higher density sinks below
    ocean (Yellow)
  • Hypopycnal flow lower density floats on ocean
    (Mississippi)
  • Concentration, grain size and suspended vs.
    bedload ratio
  • Water depths
  • Mouth
  • Basin
  • Water discharge
  • Water inflow velocity

88
Delta Processes
  • Inertia-dominated deltas
  • deep water, steep slopes, high river flow
    velocity
  • moderate sediment transport, large flow expansion
  • Friction-dominated deltas
  • shallow water, low slopes,
  • proximal sediment transport, large bars, limited
    flow expansion
  • hyperpycnal flow possible
  • Buoyancy-dominated deltas
  • deep water, hypopycnal flow, large suspended load
  • distant sediment transport, flow rafting ? plumes

89
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90
Delta Morphology
91
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92
River-Dominated Deltas
93
Lobe-Switching
94
Inter-distributary bays
95
Mahakam River-Dominated Delta
96
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97
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98
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99
Wave-dominated Grijalva Delta
100
Bramaputra Delta - India
101
Tide-Dominated Niger Delta
102
Tide-Dominated Niger Delta
103
DeltaSuccessions
104
Delta Succession
105
Wave-DominatedDelta Succession
106
Delta Collapse
107
Delta Collapse
108
Fan-Deltas
109
Deltaic Succession
110
Deltaic Succession
111
Deltaic Succession
112
Types of Depositional Systems
  • marine ? ocean, sea
  • terrestrial ? land
  • transitional ? part land, part ocean

113
Marine Depositional Systems
  • wave-dominated coasts
  • tide-dominated coasts
  • fluvial-dominated coasts (deltas)
  • carbonate reefs
  • clastic shelves platforms
  • carbonate shelves platforms
  • deepwater fans
  • pelagic abyssal plains

114
Deep SeaDepositional Systems
115
Deep Sea Depositional Systems
116
Characteristics of Deepwater Systems
  • Sediments fine upward from marine fans
  • Sand bodies form lobes perpendicular to basin
    margin
  • Formed by a mix of fluvial input, and turbidite
    currents
  • Facies
  • Subdivided erosion surfaces formed during
  • Migrating fan lobe fill
  • Dropping in base level
  • Local channels
  • Rising in base level
  • Poor to well sorted litharenites common
  • Sedimentary structures
  • Fining upward cycles that coarsen up as
    depo-center of lobes migrate
  • Up dip channel cut and fill
  • Gently seaward dipping thin parallel lobate
    sheets
  • Geometries
  • Confined incised channels
  • Open lobate sheets perpendicular and occasionally
    parallel to shore
  • Fauna flora
  • Restricted Marine fauna often in over bank shales

117
Deep Sea Fan Depositional Systems
  • Form in the moderate to deep ocean, down-dip of
    submarine canyons and often deltas
  • Large sediment flux, high sedimentation rate,
    large area
  • Gravity flow transport and deposition
  • turbidity currents
  • subaqueous debris flows
  • suspension fall-out
  • Lobes and lobe-switching important
  • Both coarse and fine grained sediment
  • Often well-sorted and normally graded

118
Bengal Fan Ganges-Brahmaputra Delta
119
Submarine Canyons and Deep Sea Fans
After Press Siever, 98
120
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121
Submarine Canyons
USGS Redondo Submarine Canyon, Southern Santa
Monica Bay
122
USGS Image
123
Submarine Canyons Deep Sea Fans
Offshore Los Angeles
USGS Image
124
Submarine Fan Morphology
125
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126
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127
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128
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129
SubmarineFan Types
130
Turbidity Currents ? Turbidites
131
Gravity Flows Turbidity Currents
132
Turbidity Currents Hemipelagic Sediment
133
Deep Water Fan Deposits
134
Deep Water Fan Deposits
135
Turbidites
136
Coarse-grained Turbidites
137
Coarse-grained Turbidites
138
Turbidites
139
Proximal Turbidites
140
Distal Turbidites
141
Soft-Sediment Deformation
142
Submarine Channels
143
Delaware Mountains Basin Fans
Deepwater Channel
Channel Sands
Kendall Photo
144
Brushy Canyon Group - Base of Slope Permian Basin
Channel Fill Turbidites
Kendall Photo
145
Brushy Canyon Group - Base of Slope - Permian
Basin
Margin of submarine fan channel incised into
"overbank". Channel fill with amalgamation as
well as flowage injection of sand into the
surrounding strata of the channel walls.
U.S. Highway 62-180 south of Guadalupe Pass
Kendall Photo
146
Pelagic Depositional Systems
  • Form in the open ocean or open (large) lakes and
    seas
  • Small sediment flux, very low sedimentation rate
  • Suspended load current transport
  • Surface waves
  • Tidal waves (not tsunami!)
  • Fluvial input
  • Turbidity currents sub-aqueous debris flows
  • Suspension fall-out deposition
  • Fine-grained (clay, mud and silt) deposition
  • Carbonates
  • Siliciclastic mudstones

147
Pelagic Sediments
148
Deep Marine Sedimentation
149
Pelagic Sediments
150
Calcareous Microfossils
151
CCD
152
Abyssal Plains
153
Siliceous Microfossils
154
Siliceous Microfossils ? Chert
155
Siliceous Microfossils ? Chert
156
Aeolian Dust
157
Aeolian Dust
158
Aeolian Dust
159
Dropstones
160
Types of Depositional Systems
  • marine ? ocean, sea
  • transitional ? part land, part ocean
  • terrestrial ? land

161
Terrestrial Depositional Systems
  • Alluvial Fan
  • Fluvial
  • Glacial
  • Eolian
  • Lacustrine
  • Playa

162
Terrestrial Depositional Systems
  • Alluvial Fan
  • Fluvial
  • Glacial
  • Eolian
  • Lacustrine
  • Playa

163
Alluvial Fan System Characteristics
  • Sediments fine upward within fan lobes
  • Sand bodies form lobes perpendicular to basin
    margin
  • Formed by a mix of fluvial input, and mass
    sediment movement
  • Facies
  • Subdivided erosion surfaces formed during
  • Migrating fan lobe fill
  • Dropping in base level
  • Local channels
  • Rising in base level
  • Poor to well sorted litharenite boulders, gravels
    and sands common
  • Sedimentary structures
  • Fining upward cycles that coarsen up as
    depo-center of lobes progrdes
  • Up dip channel cut and fill
  • Gently seaward dipping thin parallel lobate
    sheets
  • Geometries
  • Confined incised channels
  • Open lobate sheets perpendicular and occasionally
    parallel to Mt front
  • Fauna flora
  • Terrestrial flora can be common in over bank
    lobes

164
Alluvial Fan Depositional Systems
  • Form upon exit of drainage basin from a mountain
    front
  • Mix of sediment gravity flow fluid flow
    depositional processes
  • Debris flows
  • Hyperconcentrated flows
  • Fluvial channels
  • Sheetfloods
  • Lobe-switching processes produce cone
  • Radial sediment dispersal
  • Decreasing grain size downslope

165
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166
exit gorge
active lobes
167
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168
Drainage Depositional Basins
169
Alluvial Fan Architecture
Spearing, 1974
170
Alluvial Fans
Blair McPherson. 1994
171
Alluvial Fan Architecture
Kelly Olson, 1993
172
Alluvial and Fluvial Fans
  • Stream-dominated Alluvial Fans D 10 Km S
    5-15º
  • Gravity-flow Alluvial Fans D 10 Km S
    5-15º
  • Talus Cones D lt 1 Km S 10-30º
  • Fluvial Megafans D 50 -100s Km S lt 1º

173
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174
Alluvial Fan Stratigraphy
Nemec Steel, 1984
175
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176
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177
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178
Stream-dominated AF Stratigraphy
Boothroyd, 1972
179
Gravity-Flow AF Stratigraphy
Blair, 1987
180
Alluvial Fan Architecture
Gloppen Steel, 1980
181
Terrestrial Depositional Systems
  • Alluvial Fan
  • Fluvial
  • Glacial
  • Eolian
  • Lacustrine
  • Playa

182
Fluvial System Characteristics
  • Sediments fine upward within channel fill
  • Sand bodies fine distally from channels
  • Formed by a mix of fluvial bedload, and fine
    suspended sediment
  • Facies
  • Subdivided erosion surfaces formed during
  • Migrating channel fill
  • Dropping in base level
  • Local channels
  • Rising in base level
  • Poor to well sorted litharenite gravels, sands
    and shales common
  • Sedimentary structures
  • Fining upward cycles that fill channels
  • Up dip channel cut and fill
  • Gently dipping thin parallel lobate sheets
    perpendicular to channels
  • Geometries
  • Confined incised channels
  • Open lobate sheets perpendicular and occasionally
    parallel to channels
  • Fauna flora
  • Terrestrial flora can be common in over bank
    sediments

183
Fluvial Depositional Systems
  • Dominant conduit from regions of sediment
    production (mountains) to sediment storage
    (oceans, basins)
  • Characterized by channel pattern
  • Meandering
  • Braided
  • Anastomozing
  • Characterized by sediment load
  • Bedload
  • Suspended load
  • Mixed load
  • Unidirectional sediment dispersal

184
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185
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186
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187
Fluvial Channel Patterns
188
Fluvial Channel Patterns
Schumm Khan, 1972
189
Meandering Streams
190
Meandering Fluvial System
Allen, 1964
191
Thalwegs
192
Avulsion
Cross et al., 1989
193
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194
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195
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196
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197
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198
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199
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200
Meandering Fluvial Architecture
201
Braided Fluvial Architecture
Nemec, 1992
202
Fluvial Channels
Hirst, 1991
203
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204
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205
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206
Maturity
207
Fluvial Characterization
Schumm, 1981
208
Fluvial Channel Patterns
209
Orton Reading, 1993
210
Terrestrial Depositional Systems
  • fluvial
  • alluvial fan
  • glacial
  • eolian
  • lacustrine
  • playa

211
GLACIERSAND GLACIATION
212
Past Glacial Periods
  • Pre-Cambrian at end of Neoproterozoic eon
  • End of the Ordovician
  • Late Carboniferous (Pennsylvanian through
    Permian
  • Pleistocene

213
Glacial Periods
214
The Snowball Earth
  • During last ice age max, 21,000 years ago, North
    America Europe covered by glaciers over 2
    kilometers thick, sea level dropped 120 meters.
    Global chill land sea ice covered 30 t of
    Earth, more than at other times in last 500
    million years
  • Near end of Neoproterozoic eon (1000-543 million
    years ago), glaciation immediately preceded first
    appearance of recognizable animal life some 600
    million years ago

215
Paul Hoffman Daniel Schrag - Snowball Earth
  • Sun abruptly cooled or Earth tilted on its axis
    or experienced an orbital blip that reduced solar
    warmth or carbon dioxide increased?
  • ice sheets covered continents seas froze almost
    to equator, events that occurred at least twice
    between 800 million 550 million years ago
  • Each glacial period lasted millions of years
    ended under extreme greenhouse conditions.
    Climate shocks triggered evolution of
    multicellular animal life, challenge long-held
    assumptions regarding the limits of global change

216
SnowballEarth- Rocky cliffs along Namibia's
Skeleton Coast.
217
SnowballEarth- Drop Stones
218
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219
Glacial System Characteristics
  • Signal extremes in local climate sea level
    position
  • Stratigraphic markers of glacial events
  • Source of tillite (pebbles larger fragments
    supported in fine-grained matrix ) deposited from
    glaciers.
  • Massive tillite inferred deposited below ice
    sheets or dropping from marine supported ice in
    submarine setting
  • Banded tillite may be deposited by ice sheets
  • Laminites common in lakes (Varve), Loess dust on
    land
  • Supraglacial pro-glacial deposits with
    stratified conglomerates sandstone
  • U Shaped valleys glacial striae
  • Mountain glaciation could be source of much
    downslope fluvial sediment

220
Simplified Glacial Systems signals
  • Sediment signal a mix of
  • Glacial carried dumped in moraines
  • Water born fluvial sediment
  • Lacustrian varves
  • Aeolian loess
  • Erosion
  • U-shaped valleys
  • Eroded rock surface
  • Grooved
  • Plucked
  • Striated
  • Base level changes in sea level.

221
Glacial Setting
Currently forms 10 of earthss surface,
Pleistocene reached 30, but in Pre Cambrian
could have reached 100
  • Develop where all of annual snow doesnt melt
    away in warm seasons
  • Polar regions
  • Heavy winter snowfall e.g. Washington State
  • High elevations e.g. even equator
  • 85 in Antarctica
  • 10 in Greenland

222
Adelie Penguins Taking a Dive
223
Glacial Erosion
  • Under glacier
  • Abrasion plucking
  • Bedrock polished striated
  • Rock flour washes out of glacier
  • Polishing and rounding
  • Sheep Rocks
  • Striations- scratches grooves on rock
  • Above glacier
  • Frost wedging takes place
  • Erosion by glaciers steepens slopes

224
Roche Moutone Ice Sheet Plucking
225
Glacial Scarring Of Bedrock - Findelen
Glacier Switzerland - Matterhorn In Background
226
Glacial Sediments
  • Facies of continental glacial settings
  • Grounded Ice Facies
  • Glaciofluvial facies
  • Glacial lacustrine facies
  • Facies of proglacial lakes
  • Facies of periglacial lakes
  • Cold-climate periglacial facies
  • Facies of marine glacial settings
  • Proximal facies
  • Continental Shelf facies
  • Deepwater facies

227
Glacial Deposition
  • Till
  • Unsorted debris in fine matrix
  • Erratic
  • Moraine- body of till
  • Lateral Moraine
  • Medial Moraine- where tributaries join
  • End moraine-
  • Terminal
  • Recessional
  • Ground moraine
  • Drumlin

228
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229
Twenty Mile Medial Moraine
230
Robinson Tumbling Glacier Brit. Columbia
231
Ground and End Moraines
232
Glacial Lakes - Ireland
233
Glacial Sediments
234
Varves
235
Glaciation Subdividing Surfaces
236
Glacial Sediments
  • Facies of continental glacial settings
  • Grounded Ice Facies
  • Glaciofluvial facies
  • Glacial lacustrine facies
  • Facies of proglacial lakes
  • Facies of periglacial lakes
  • Cold-climate periglacial facies
  • Facies of marine glacial settings
  • Proximal facies
  • Continental Shelf facies
  • Deepwater facies

237
Glacial Systems - Conclusions
  • Signal extremes in local climate sea level
    position
  • Stratigraphic markers of glacial events
  • Source of tillite (pebbles larger fragments
    supported in fine-grained matrix ) deposited from
    glaciers.
  • Massive tillite inferred deposited below ice
    sheets or dropping from marine supported ice in
    submarine setting
  • Banded tillite may be deposited by ice sheets
  • Laminites common in lakes (Varve), Loess dust on
    land
  • Supraglacial pro-glacial deposits with
    stratified conglomerates sandstone
  • U Shaped valleys glacial striae
  • Mountain glaciation could be source of much
    downslope fluvial sediment

238
Simplified Conclusions Glacial Systems
  • Sediment signal a mix of
  • Glacial carried dumped moraines
  • Water born fluvial sediment
  • Lacustrian varves
  • Aeolian loess
  • Erosion
  • U-shaped valleys
  • Eroded rock surface
  • Grooved
  • Plucked
  • Striated
  • Base level changes in sea level.

239
AEOLIANAND DESERTS
240
Sandy Desert N. Africa Going
241
Aeolian System Desert Coast
  • Distribution of Aeolian systems Holocene
    Ancient
  • Deserts Transport Depositional Sytems Wind
    Fluvial Action
  • Deposits of Modern Deserts
  • Dunes
  • Interdunes
  • Sheet Sands
  • Aeolian Systems
  • Bounding Surfaces
  • Ancient Deposits

242
Simplified Desert Systems signals
  • Sediment signal a mix of
  • Aeolian sediment dunes and sheets
  • Water born intermittent fluvial sediment
  • Playas and lakes
  • Aeolian loess
  • Erosion
  • Water table Stokes Surfaces marks limit
  • Incised valleys
  • Gravel remnants
  • Rock pavements
  • Ventifacts
  • Base level changes in ground water level.

243
Desert
  • Region with low precipitation
  • Usually less than 25 cm rain per year
  • Distribution
  • Most related to descending air
  • Belts at 30 degrees North South latitude
  • Rain shadow of mountains
  • Great distance from oceans
  • Tropical coasts beside cold ocean currents
  • Polar desserts

244
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245
Earth'sGeneralCirculation
246
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247
Rain Shadow Deserts
248
Deserts Dune Factories
Common characteristics-
  • Lack of through-flowing streams
  • Internal drainage
  • Local base levels
  • Desert thunderstorms
  • Flash floods
  • Mudflows

Dominated by water transportation
249
Deserts Depositional Systems
Dunes fed by water transported sediment
  • Margin rimmed by incised seasonal streams (Wadiis
    or Arroyo)
  • In turn flanked by alluvial fans and rock
    pavements or bajada
  • Intermittent drainage supplying sediment
  • Dunes
  • Playas

250
Bajada PedimentAlluvialFans -Namibia
251
Alluvial fans Death Valley
252
Salt Pan Alluvial Fans Death Valley
253
Sediment Source - Deserts Coasts
  • Abundant sediment supply (sand, silt)
  • Favorable wind regimes
  • Grain transport in wind
  • Transport populations resultant deposits
  • i. Traction (deflation pavements)
  • ii. Saltation (sand dunes)
  • iii. Suspension (loess)
  • III. Subenvironments of eolian dune systems

Dominated by water transportation
254
Wind Erosion and Transportation
  • Sand
  • Moves along ground- saltation
  • Sandstorms
  • Sandblasting up to 1 meter
  • Ventifact
  • Deflation
  • Blowout
  • Dust storms

255
Sand Movement
256
Brice Canyon - Utah
257
Arches National Park Utah
258
Wind Erosion and Transportation
  • Dust storms
  • Sand
  • Moves along ground- saltation
  • Sandstorms
  • Sandblasting up to 1 meter
  • Ventifact
  • Deflation
  • Blowout

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260
Wind Action
  • Strong in desert because
  • Low humidity
  • Great temperature ranges
  • More effective because of lack of vegetation
  • Effective erosion in deserts because sediment is
    dry

261
Wind Erosion and Transportation
  • Sand
  • Moves along ground- saltation
  • Sandstorms
  • Sandblasting up to 1 meter
  • Ventifact
  • Deflation
  • Blowout
  • Dust storms

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263
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264
Wind Erosion and Transportation
  • Sand
  • Moves along ground- saltation
  • Sandstorms
  • Sandblasting up to 1 meter
  • Ventifact
  • Deflation
  • Blowout
  • Dust storms

265
Red Sea Dust Storm
RedSeaDustStorm
266
North Africa - Sea Dust Storm
267
Wind Erosion and Transportation
  • Dust storms
  • Wind-blown dust accumulates in the deep ocean
    floor at a rate of 0.6 x 1014 g/year.

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269
Loess
270
Wind Deposition
  • Loess
  • Gravel Pavements
  • Desert varnish petroglyphs
  • Sand Dunes
  • Well-sorted, well-rounded sand grains
  • Slip face
  • Angle of repose
  • Wind ripples

271
Desert Pavement Formation
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273
Wind Deposition
  • Loess
  • Gravel Pavements
  • Desert varnish petroglyphs
  • Sand Dunes
  • Well-sorted, well-rounded sand grains
  • Slip face
  • Angle of repose
  • Wind ripples

274
Wind Deposition
  • Loess
  • Gravel Pavements
  • Desert varnish petroglyphs
  • Sand Dunes
  • Well-sorted, well-rounded sand grains
  • Slip face
  • Angle of repose
  • Wind ripples

275
Barchan Dunes - Jordan
276
Zion National Park - Utah
277
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278
Wind Deposition
  • Loess
  • Gravel Pavements
  • Desert varnish petroglyphs
  • Sand Dunes
  • Well-sorted, well-rounded sand grains
  • Slip face
  • Angle of repose
  • Wind ripples

279
Dune Evolution
280
Hierarchies exhibited by aeolian and associated
sediments
  • Grains
  • Ripples
  • Dunes
  • Interdune unconfined sheets
  • Confined bodies of wadii channel fills
  • Playa unconfined sheets of heterogenous chemical,
    wind and water transported clastic sediments

281
Mechanisms of Aeolian Transportation
  • Rolling 2-4 mm
  • Surface creep
  • 20-25 of sand moves by grains shifted by
    impacting saltating grains lt 2 mm
  • Suspension fine sand, silt, clay
  • Grains 0.1 mm are most easily moved by wind
    mostly gt 2 m above the ground surface

282
Mice Tracks RipplesWhite Sands, NM
283
Ripples on Dune
284
Wind Deposition
  • Types of dunes
  • Barchan
  • Transverse dune
  • Parabolic dune
  • Longitudinal dune

285
Salt Pan West Texas, El Capitan
LONGITUDINAL
BARCHAN
PARABOLIC
TRANSVERSE
STAR
BARCHINOID
286
North Africa - Sea Dust Storm
Star Dunes Namibia
287
Sahara Barchans Camels
288
Navajo Sandstone
289
Cross-bedded Navaho Sandstone
290
NavajoSandstone
291
Quaternary of UAE Stokes Surface
292
NavajoSandstone
Base level change punctuates the sandstone with
erosion surfaces!
293
NavajoSandstone
Base level change punctuates the sandstone with
erosion surfaces!
294
NavajoSandstone
Base level change punctuates the sandstone with
erosion surfaces!
295
Some characteristics of deserts
  • Stream channels normally dry
  • covered with sand gravel
  • Narrow canyons with vertical walls
  • Resistance of rocks to weathering
  • Desert topography typically steep and angular

296
Aeolian Sediment - Critical Character
  • Aeolian sediments evidenced by x-bedding with
    high angle (30-34 degrees)
  • Horizontal thin laminae common locally
  • Sand rounded and frosted
  • Quartz coated by iron oxide suggests hot arid
    and/or seasonally humid climate (exceptions)
  • Well Sorted often unimodal but if bimodal two
    populations present
  • Silt and clay minimal

297
Aeolian Sediment - Critical Character
  • Small large scale cross bedding, with multiple
    orientations within horizontal bedding
  • Grains in laminae well sorted, especially finer
    sizes, sharp differences in size between lamina
  • Size ranges from silt (60 mu) to coarse (2mm)
  • Max size transported by wind 1 cm but rare
    grains over 5 mm
  • Larger grains (0.5 - 1.mm) often well rounded
  • Sands free of clay and clay drapes rare
  • Uncemented sands have frosted surfaces
  • Mica usually absent

Rules of thumb - Glennie1970
298
Aeolian sediment interpretation
  • Analyse sedimentology internal architecture
    with outcrop, cores and downhole imaging
  • Identify seperate single aggradational units
    bounded by regional deflation surfaces
    (deep-scoured to flat surfaces)
  • Genetic models from cyclic recurrence in facies
  • Aggradation characterises near- continuous
    accumulation
  • Internal facies evolution related to differences
    in sediment budget moving water table
  • Palaeosols provide evidence of climate change

299
Conclusions - Desert Systems - Simplified
  • Sediment signal a mix of
  • Aeolian sediment dunes and sheets
  • Water born intermittent fluvial sediment
  • Playas and lakes
  • Aeolian loess
  • Erosion
  • Water table Stokes Surfaces marks limit
  • Incised valleys
  • Gravel remnants
  • Rock pavements
  • Ventifacts
  • Base level changes in ground water level.

300
LAKE AND ORGANICS
301
Lakes Are Ephemeral
302
Lacustrian Systems
  • Critical characteristics of system?
  • Geomorphologic tectonic setting
  • Dominant sedimentary processes
  • Facies
  • Subdividing surfaces
  • Lithology
  • Sedimentary structures
  • Geometries Confined versus open
  • Fauna flora

303
Lake Systems Simplified Signals
  • Sediment signal a mix of
  • Lake Center sheets and incised unconfined
    turbidite cycles
  • Margins marked by alluvial fans fluvial
    sediment
  • Reducing setting that favors organic preservation
  • Signal cycles in order from
  • Clastics organics
  • Limestone organics
  • Evaporites organics
  • Base level changes in ground water level
  • Origin of large lakes
  • Continental break up
  • Continental collision
  • Sags on craton

304
Significance of Lake Systems
  • Signal extremes in local climate geochemistry
  • Stratigraphic markers (Organics trap radioactive
    minerals)
  • Major source of hydrocarbons along Atlantic
    Margins
  • Major source of oil shale gas in western USA
    Canada
  • Major source of
  • Trona (Hydrated Sodium Bicarbonate Carbonate)
  • Borax (Hydrated Sodium Borate)
  • Sulfohalite (Na6ClF(SO4)2)
  • Hanksite (Sodium Potassium Sulfate Carbonate
    Chloride)

305
Lake Geomorphologic Tectonic Setting
Temporary features forming 1 of earthss land
surface, filling-
  • Major rifted, faulted (Break-up) continental
    terrains E. Africa
  • Major final fill of foreland basin Caspian
    Aral
  • Continental sags Victoria, Kenya, Uganda, and
    Eyre
  • Glacial features including
  • Moraine damming and/or ice scouring Great Lakes
  • Ice damming
  • Landslides or mass movements
  • Volcanic activity including
  • Lava damming
  • Crater explosion and collapse Crater Lake
  • Deflation by wind scour or damming by wind blown
    sand - Fayum
  • Fluvial activity including
  • Oxbow lakes
  • Levee lakes,
  • Delta barrier island entrapment

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307
Lake Tanganyika
308
Lake Tanganyika
309
Lake Tanganyika
  • Lake levels have varied historical and earlier
  • Fossil and living stromatolites abundant around
    the margins of Lake Tanganyika, Africa provides a
    source of paleolimnologic and paleoclimatic
    information for the late Holocene
  • late Holocene carbonates suggests that the
    surface elevation of the lake has remained near
    the outlet level, with only occasional periods of
    closure
  • In past the lake draw down encouraged evaporites

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312
Lakes formed between splitting continents
313
Restricted Entrances To Sea
Isolated linear Belt of interior drainage
Regional Drainage Away From Margin
Organic Rich Lake Fill
Arid Tropics Air System
Wide Envelope of surrounding continents
314
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315
Lakes flanking Major Mountain Chains
316
Caspian and the Arral Sea
  • Bodies of fresh to saline water trapped on craton
    behind major mountain chains
  • Tend to act as traps to clastics, carbonates and
    evaporitic sediments
  • Climatic change is recorded in the record of the
    sediment fill
  • Water draw down encourages evaporites

317
Caspian
318
Aral Sea
319
Great Lakes
320
Great Lakes
  • Bodies of fresh water trapped on glacially
    scoured depressions on craton behind glacial
    moraines
  • Act as traps to clastic sediments
  • Climatic change is recorded in record of sediment
    fill
  • Water draw down encourages precipitates

321
Lake Constance - Switzerland
322
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323
Ice Dammed Lake Alaska
324
Lake Response to Stratification
325
Lake Sedimentary facies
  • Sedimentary signal like that of a foreshortened
    Marine setting
  • Narrow shores with beaches and deltas
  • Finer sediments and turbidites fill the lake
    center

326
Lake Sedimentary facies
  • Presence of freshwater fossils
  • Lake sediments commonly better sorted than
    fluvial and periglacial sediments
  • May (or may not) display a tendency toward fining
    upward and inward towards the basin center
  • Lake sediments are predominantly fine grained
    sediments either siliciclastic muds but may be
    carbonate sediments and evaporates
  • Typical sequence may produced as the lake dries
    up with a coarsening upward sequence from
    laminated shales, marls and limestones to rippled
    and cross-bedded sandstone and possibly
    conglomerates
  • Lake sediment fill often shows cyclic alternation
    of laminae
  • Varves produced by seasonal variations in
    sediment supply and lake circulation which
    changes the chemistry of the lakes

327
Lacustrian sedimentary geometries
  • Shore marked by linear beaches
  • Coarse to fine slope
  • Deeper water lake laminae and turbidites
  • Eclectic clastic and evaporitic sedments

328
GreenRiver Lake
329
Green River Lake Fill
330
Green River Systems Facies
331
Green River Section
332
Green River Section
333
Green River Section
334
Green River Fauna Flora
335
East African Lake Margin
336
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337
Green River Section
338
Conclusions - Lake Systems
  • Sediment signal a mix of
  • Lake Center sheets and incised unconfined
    turbidite cycles
  • Margins marked by alluvial fans fluvial
    sediment
  • Reducing setting that favors organic preservation
  • Signal cycles in order from
  • Clastics organics
  • Limestone organics
  • Evaporites organics
  • Base level changes in ground water level
  • Origin of large lakes
  • Continental break up
  • Continental collision
  • Sags on craton

339
Lakes Are Ephemeral
340
End of the Lecture
  • Lets go for lunch!!!
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