Sedimentary Cycle Processes Flashcards
is a simple model of the processes
responsible for the production of sediments and
sedimentary rocks.
Sedimentary Cycle
Called second set of processes
Erosion
referred when sediments accumulate on Earth’s surface
Deposition
sedimentary material is moved or transported in solid or dissolved form across Earth’s surface.
Transportation
Erosion rates depend primarily on: (4)
relief
vegetative cover
precipitation
the type of erosion agents involved
Erosion, transportation and deposition agents
4
Water
Wind
Glaciers
Mass flows
is the major agent by which sediments are eroded, transported and deposited on Earth’s surface.
Water
is the major agent by which
sediments are eroded, transported and
deposited on Earth ’ s surface.
Fluid Flow
possess shear strength. The major stress that initiates flow is the tangential force of gravity (gt), which increases with increasing slope angle.
Plastic Flow
adjacent parcels of the flow move roughly parallel to one another in a well -organized pattern, with negligible mixing between them.
Laminar Flow
adjacent parcels of the flow move in chaotic patterns and random mixing between parcels is common
Turbulent Flow
Can be used to predict whether flow will be
laminar or turbulent
Essentially a ratio between the inertial forces and
the viscous forces in a fluid medium
named after
Reynold’s Number
Osborne Reynold
are capable of picking up loose clay, silt and sandsized debris from the land surface
Wind
In temperate (warm based) glaciers, erosion of the bedrock by ice occurs by two processes
Abrasion and Plucking.
is most common where a glacier flows over an obstacle. The blocks plucked by the ice and subsequently incorporated into the glacier are often
loosened by subglacial freeze–thaw action.
Glacial Plucking
is most effective where the land surface is
not bound by plants and hence it is prevalent where
vegetation is sparse, in cold regions, such as near the
poles and in high mountains, and dry deserts.
Wind Erosion
- occurs by the frictional action of blocks of material embedded in the ice (‘tools’) on the bedrock. The scouring process creates rock flour, clay and
silt-sized debris that is incorporated into the ice.
Glacial Abrasion
On steep slopes in mountainous areas and along
cliffs movements downslope under gravity are
commonly the first stages in the erosion and
transport of weathered material.
Mass Flow
It can attain much higher velocities and is generally
characterized by turbulent flow
Wind
TRANSPORT MEDIA (4)
GRAVITY
WATER
AIR
ICE
Simplest mechanism of sediment transport where
sediments move under the influence of gravity
down a slope
Gravity
movements of material under gravity and
accumulates as a chaotic mass of material at the base of the slope.
Rock Fall
coherent mass of bedrock that has moved
downslope without significantly breaking up in the
process.
Landslide
slow movement of lubricated regolith/soil.
Soil Creep
instantaneous events like slides but the
material is plastic due to saturation by water and it
deforms during movement downslope
Slumping
dense, viscous mixtures of sediment and
water in which the volume and mass of sediment
exceeds that of water. Deposition occurs when internal
friction becomes too great and the flow ‘freezes’.
Debris Flow
are gravity-driven turbid mixtures
of sediment temporarily suspended in water. They are
less dense mixtures than debris flows
Turbidity Current
What type of Mass Wasting?
- Rock, Flow, Rapid
- Rock, Slide, Moderate
- Rock, Flow, Fast
- Rock, Slide/Flow, Slow
- Rock, Flow, Moderate to Rapid
- Avalanche
- Rockslide
- Rockflow
- Rock Creep
- Topple
◂ All molecules within fluid move parallel to
each other
◂ Heterogeneous fluids almost don’t mix
◂ Low Reynolds Number (<500)
Laminar Flow
What type of Mass Wasting?
- Loose Material, Flow, Moderate
- Loose Material, Flow, Slow
- Loose Material, Flow, Slow to Moderate
- Loose Material, Slide, Moderate to Fast
- Loose Material, Slide/Flow, Fast
- Debris/ Mud Flow
- Earth Creep
- Earth Flow
- Debris Slide
- Debris Avalance
High water content mass wasting
4
Soil Creep
Turbidity Currents
Debris Flow
Slumping
◂ Molecules in the fluid move in all direction
but with net movement in transport direction
◂ Heterogeneous fluids mix thoroughly
◂ High Reynolds Number (>2000)
Turbulent Flow
the clasts move by rolling along at the bottom of the air or water flow without losing contact with the bed surface.
Rolling
the particles move in a series of jumps, periodically leaving the bed surface, and carried short distances within the body of the fluid before returning to the bed again.
Saltation
Generally exerts smaller shear stresses on the bottom and therefore tends to entrain and transport smaller particles.
Wind
the clasts move by sliding along at the
bottom of the air or water flow without losing
contact with the bed surface
Traction
turbulence within the flow produces sufficient upward motion to keep particles in the moving fluid more-or-less continually.
Suspension
there is a decrease (fining) in grain size from bottom
to top
Normal Grading
What kind of grading does Bouma Sequence show
- Vertically?
- Laterally?
- Normal
2. Reverse
Where is the complete sequence found?
Oman
morphological feature formed by the interaction
between a flow and cohesionless sediment on a
bed.
◂ Recognition of sedimentary structures generated
by bedforms provides information about the
strength of the current, the flow depth and the
direction of sediment transport.
Bedforms
thin, inclined layers of sand, which build up to form the
sedimentary structure referred to as ______
◂ They form as current ripples migrates downstream and sediments deposit on its lee slope forming a
series of layers at the angle of the slope.
Cross Laminae
Cross Lamination
- a disturbance travelling through a gas, liquid or
solid which involves the transfer of energy between
particles.
◂ The oscillatory motion of the top surface of a water body
produced by waves generates a circular pathway for
water molecules in the top layer
Wave
when grain size increases (coarsening) from top to
bottom
Reverse Grading
have long, straight to sinuous crests which may
divide.
could also be symmetrical with cross-laminae dipping in both directions either side of the crests.
Wave Ripple
A normal graded beds where the coarsest
particles settle first then succeeding finer
particles settle after.
Bouma Sequence
are waning flows, that is, they decrease velocity through time as they deposit material, but this means that they also decrease velocity with distance from the source.
Turbidity Current
Composition of Bouma Sequence Layers
Ta - Tb - Tc - Td - Te -
Ta - Massive
Tb - Laminated Sand
Tc - Cross-laminated Ripples
Td - Laminated Silt
Te - Hemipelagic Mud
deposited by these flows have
a thicker coarse unit at their base, which can
be divided into three divisions.
S1/S2- Traction deposits
S3 - Rapid deposition
turbidites
A general term for clay-rich sediment that is
cohesive and the individual particles tend to stick
to each other as sediment dries out
Mud Cracks
Polygonal pattern of cracks as the sediment
dries out
◂ a very reliable indicator of the exposure of the
sediment to subaerial conditions
Desiccation Cracks
Small-scale erosional features on a bed surface
◂ They are preserved in the rock record when
another layer of sediment is deposited on top
leaving the feature on the bedding plane.
includes _____ and _____
Sole Mark
Tool Mark and Flute Casts/Mark
Turbulent flows that erode the underlying bed creates
Flute Casts
shrinkage cracks that form under water in
clayey sediments
◂ are simple, straight or slightly curved tapering
cracks
Synresis Cracks
formed by a saltating object
Prod, skip or bounce marks
The physical breakdown and chemical
alteration of rocks at or near Earth’s surface
Weathering
- transfer of rock and soil downslope under
the influence of gravity
Mass Wasting
- the physical removal of material by mobile
agents such as water, wind, or ice
Erosion
is the breakdown of larger, more coherent rock bodies into smaller fragments of the same composition.
Disintegration
is any breakdown of rock materials that involves changes in chemical composition
Decomposition
Dominant process in the production of
soils
Weathering
rock materials weather at different rates
Differential Weathering
Formed when an object being carried by a flow
create marks on the bed surface
Tool Mark
are sharp elongate marks created by an object
being dragged along the bed.
Grooves
FACTORS AFFECTING WEATHERING
Mineralogy of the Parent Rock
Climate
No. of Fissures
Time
Dominant Weathering Physical or Chemical
- Humid Climate
- Dry Climate
- Chemical
2. Physical
Accomplished by physical forces that break rock
into smaller and smaller pieces without
changing the rock’s mineral composition
Mechanical Weathering
Involves a chemical transformation of rock into
one or more new compounds.
Chemical Weathering
After water works its way into the cracks in rock, the freezing water enlarges the cracks and angular
fragments are eventually produced.
Frost Wedging
– develops along surfaces parallel to Earth’s surface
when water freezes along bedding planes and/or sheet fractures.
Frost Heaving
Begins when sea spray from breaking waves or salty
groundwater penetrates crevices and pore space in rock
Salt Crystal Growth
Onion-like layers produced when large masses of igneous rocks are exposed by erosion, concentric slabs begin to break loose
Sheeting
Created by continued weathering eventually
causes the slabs to separate and
spall off
Exfoliation Domes
states that the susceptibility of common igneous
minerals is inversely proportional to their crystallization
temperature as summarized in Bowen’s reaction series
Goldich Rule
Chemical reaction between a mineral and water in
which dissolved hydrogen ions and/or hydroxyl ions
are added to form one or more new minerals.
Hydrolysis
Chemical reaction in which one or more electrons
are transferred from a cation in the mineral to an
anion, increasing the valence of the cation.
Oxidation
Acids such as carbonic acid readily decompose many
rocks and produce certain products that are water
soluble. (e.g., Calcite)
Solution
involves the addition of water to a
crystal structure during the reaction between
and mineral and the aqueous solution
Hydration
Gives the weathered rock a more
rounded or spherical shape.
Spheroidal Weathering
A type of weathering brought by various activities
of living organisms.
Biological Weathering
rocks are pried apart and fractures enlarged as
root systems expand during growth
Root Growth
occurs when a force or pressure is applied to
break rocks apart or degrade the minerals in
them by either plants or animals.
Biological Weathering (Physical)
Combination of mineral and organic matter, water, and air.
Soil
Soil Profile
O A E B C R
loss of water
Dehydration
Consists of the Top Soil
O
A
living organisms contribute through their organic
compounds that contain molecules that acidify
and corrode rock minerals
an example is a microbial activity in the form of
Biological Weathering (Chemical)
lichen
Consist of the subsoil
B
Zone of Eluviation and Leaching
E
Sequence in the formation of soil profile
R C O A E B
Zone of Aluviation
A
are often known as light soils due to
their high proportion of sand and little clay
Sandy Soil
are a mixture of sand, silt and clay that are
combined to avoid the negative effects of each type.
Loam Soil
These soils are made of over 25 percent clay, and
because of the spaces found between clay particles, clay soils
hold a high amount of water.
Clay Soil
compromise of medium sized particles they are well
drained and hold moisture well
Silt Soil
are high in organic matter and retain a large amount
of moisture
Peat Soil
highly alkaline soil due to the calcium carbonate or
lime within its structure.
Geologic term of this soil
Chalk Soil
Calcrete
It emphasizes the physical and chemical properties of
the soil profile and is organized on the basis of
observable soil characteristics.
Soil Taxonomy
Soil Taxonomy Classification
Order Suborder Great Group Subgroup Family Series
Soils that result from weathering processes that leach clay minerals into the subsoil/surface where they can hold and supply moisture and nutrients to plants
Alfisols
Young soils in which the parent material is volcanic ash
and cinders deposited by recent volcanic activity
Andisol
Soils that develop in dry places; insufficient water to remove soluble minerals; may have an accumulation of calcium carbonate,gypsum, or salt in subsoil; low organic content.
Aridosol
Young soils having limited development and exhibiting
properties of the parent material.
Entisol
Young soils with little profile development that occur in regions with permafrost
Gelisol
Organic soils with little or no climatic implications.
Histosol
Weakly developed young soils in which the beginning of profile
development is evident.
Most common in humid climates, they exist from the Arctic to the tropics.
Inceptisol
◂ Dark, partially decomposed organic material commonly referred to as peat
Histosol
Dark, soft soils that have developed under grass
vegetation, generally found in prairie areas
Mollisol
Soils that occur on old land surfaces unless parent
materials were strongly weathered before they were
deposited
Oxisol
Soils found only in humid regions on sandy material
Spodosol
Can be found in any climate where organic debris can accumulate to form a bog soil.
Histosol
Soils that represent the products of long periods of
weathering
Ultisol
Beneath the dark upper horizon of weathered organic
material lies a light-colored horizon of leached material,
the distinctive property of this soil.
Spodosol
Soils containing large amounts of clay, which shrink upon
drying and swell with the addition of water
Vertisol
Tarbuck
- High Nutrient Soil
- Volcanic Soil
- Desert Soil
- New Soil
- Permafrost Soil
- Organic Soil
- Young Soil
- Prairie Soil
- Tropical Forest Soil
- Conifer Forest Soil
- Low-Nutrient Soil
- Swelling Clay Soil
- Alfisol
- Andisol
- Aridosol
- Entisol
- Gelisol
- Histosol
- Inceptisol
- Mollisol
- Oxisol
- Spodosol
- Ultisol
- Vertisol
