Chapter 3 Flashcards
There are two categories of geologic processes: __________ (external) and __________ (internal).
exogenous
endogenous
takes place within or in the interior of Earth. Thermal energy of the mantle and crust is it’s driving force.
endogenous processes
geologic process that is driven by thermal energy
endogenous process
These processes are responsible for earthquakes, and movements related to Earth’s crust.
endogenous processes
Creates relief and responsible with large scale landform building and transforming processes.
endogenous processes
occur on or near the surface of Earth. They are usually influenced or driven by gravity, water, wind or organism.
exogenous processes
Types of exogenous process are
Weathering, Erosion, Mass wasting, and Sedimentation.
Igneous Processes
______________ - Volcanic Eruptions
______________ - Igneous intrusions
Tectonic Processes
_____________ - anticlines and synclines
_____________ - rift valleys, graben, escarpment
Igneous Processes
Volcanism - Volcanic Eruptions
Plutonism - Igneous intrusions
Tectonic Processes
Folding - anticlines and synclines
Faulting - rift valleys, graben, escarpment
result from rapid rock deformation that is accompanied by violent shaking
earthquake
is the process by which rocks and minerals are broken down into smaller particles by various physical, chemical, and biological mechanisms.
weathering
It affects the composition, texture, and distribution of sediments that ultimately contribute to the formation of sedimentary rocks and depositional systems.
weathering
it is the disintegration of rocks, soil, and minerals, together with other materials through contact with Earth’s subsystems.
Weathering
Types of weathering
physical (mechanical) weathering
chemical weathering
biological weathering
The breakdown of rocks into smaller pieces without changing their chemical composition or breakdown of rocks by mechanical forces concentrated along rock fractures.
physical (mechanical) weathering
Water enters cracks in rocks, freezes, expands, and eventually causes the rock to break apart.
frost wedging
Repeated heating and cooling of rocks cause them to expand and contract, leading to fracture.
thermal expansion
rocks and sediment grind against each other, wearing down surfaces.
abrasion
Layers of rock peel away due to pressure release or thermal stress.
exfoliation
as the salt crystals grow, they apply pressure to the surrounding rock weakening it, until it eventually cracks and breaks down.
salt wedging
process in which pressure in a rock is released (unloading) along parallel alignments (sheet joints) near the surface of the bedrock
exfoliation
The breakdown of rocks through chemical reactions that alter the mineral composition. Rock decomposes, dissolves, alters, or weakens the rock through chemical processes to form residual materials. Process by which rocks break down by chemical reactions.
chemical weathering
Water reacts with minerals to form new minerals and soluble salts. A chemical reaction between H+ and OH ions in water and the minerals in the rock.
Hydrolysis
Oxygen reacts with minerals, particularly iron, to form oxides, which can weaken the rock. Accelerates rock decay, rendering it more vulnerable to other forms of weathering.
Oxidation
Process by which carbon dioxide and water chemically react to produce carbonic acid, a weak acid, that reacts with carbonate minerals in the rock. It occurs with limestone or dolomite rocks and produces very fine, clayey particles.
Carbonation
Minerals dissolve directly into water, especially those susceptible to acids.
solution
a process where mineral structure in the rock forms a weak bond with H2O
hydration
the disintegration or decay of rocks and minerals caused by chemical or physical agents of organisms.
biological weathering
(presence of organism) The breakdown of rocks by biological activities. the disintegration or decay of rocks and minerals caused by chemical or physical agents of organisms. Happens by: organic activity from lichen and algae, rock disintegration by plant growth, burrowing and tunneling organisms, and secretion of acids.
Biological weathering
Plant roots grow into cracks in rocks, expanding and causing the rock to break apart.
root expansion
These organisms produce acids that chemically weather rocks.
lichen and moss
Burrowing animals and other organisms disturb the rock structure, leading to mechanical breakdown.
animal activity
is the process by which Earth’s surface is worn away by wind, water or ice.
erosion
It takes place when there is rainfall, surface runoff, flowing rivers, seawater intrusion, flooding, freezing and thawing, hurricanes, wind, etc.
erosion
Agents of Erosion
water
wind
ice
gravity (mass wasting)
__________: Rivers, streams, and rain can erode rocks and soil, carrying them downstream.
____________: can transport fine particles over long distances, particularly in arid regions.
__________: Glaciers can erode large amounts of rock and soil as they move.
____________: Landslides and rockfalls result from gravity pulling loose material downslope.
Water
Wind
Ice
Gravity (Mass Wasting)
Buried ancient erosional surfaces are called ______________
unconformities
Two types of unconformities
disconformities
angular unconformities
is the movement of eroded material from one place to another. It is a key phase in the process of erosion, where particles that have been eroded from their original location are moved to a new area by natural forces.
transportation
Mechanism of sediment transportation
suspension
saltation
traction
solution
is where fine particles like silt and clay are carried in the water column
suspension
is where small pebbles and sand grains are bounced along the bed of a river or by the wind
saltation
is where larger rocks and boulders are rolled along the ground by water, wind, or ice
traction
is where dissolved minerals are transported in waters
solution
the grinding away of sharp edges and corners of rock fragments during transportation. It occurs in sand and gravel as rivers, glaciers, or waves cause particles to hit and scrape to one another or against a rock surface.
rounding
process by which sediment grains are selected and separated according to grain size by the agents of transportation (wind, running water)
sorting
Sediments are considered as ___________ when the grains are nearly all the same size.
well-sorted
Once sediments are transported, they are eventually _____________ when the energy of the transporting medium decreases. This can occur in various environments, such as riverbeds, lakes, ocean floors, deserts, or at the base of slopes. The deposited sediments can later form sedimentary rocks through compaction and cementation over geological timescales.
deposited
is the process by which transported material is laid down or settles in a new location.
deposition
location in which deposition occurs
environment of deposition
Deposition Examples:
- _________________: Sediments are deposited at the mouth of a river as it enters a slower-moving body of water.
- _________________: Wind deposits sand in mounds or ridges.
- __________________: Rocks and debris carried by glaciers are deposited as the glacier retreats.
Deposition Examples:
- River Deltas: Sediments are deposited at the mouth of a river as it enters a slower-moving body of water.
- Sand Dunes: Wind deposits sand in mounds or ridges.
- Glacial Moraines: Rocks and debris carried by glaciers are deposited as the glacier retreats.
is the general term for a group of processes that convert loose sediment into sedimentary rock.
lithification
is the process that packs loose sediment grains tightly together due to increasing weight of overburden, resulting to reduction of open pore space
compaction
is a process in which the precipitation of solid material around sediment grains binds them into a firm, coherent rock, resulting in further reduction of open pore spaces
cementation
what is the solid material that precipitates around sediment grains
cement
are physical features within sedimentary rocks that form during or shortly after sediment deposition.
sedimentary structures
These structures provide valuable insights into the environmental conditions prevailing at the time of deposition. These structures are critical to reservoir studies because they provide insights into the depositional environment, which in turn influences the reservoir’s porosity, permeability, and overall quality.
sedimentary structures
It may also reveal the original stratigraphic top, or upward direction of deposition which helps geologist unravel the geometry of rocks that have been folded or faulted in tectonically active regions.
sedimentary structures
two main categories of sedimentary structures
inorganic sedimentary structures
organic sedimentary structures
These are formed by physical or chemical processes without the direct involvement of biological activity.
inorganic sedimentary structures
different inorganic sedimentary structures
bed forms and surface markings
internal bedding structures
sole marks
These are features which form on the surface of a bed of sediment
bed forms and surface markings
At the time of formation, the “surface of a bed” is equivalent to the sea floor, or the bottom of a lake or river, for example. In a sequence of sedimentary rock, bed forms and surface markings are found on bedding planes.
bed forms and surface markings
different bed forms and surface markings
ripple marks
mud cracks
Small, wave-like structures formed by water or wind movement. These are undulations of the sediment surface produced as wind or water moves across sand.
ripple marks
These are undulations of the sediment surface produced as wind or water moves across sand.
ripple
ripples which form in unidirectional currents (such as in streams or rivers). Crests of asymmetrical ripples may be straight, sinuous, or lobe-like (lingoid ripples), depending on water velocity.
asymmetrical ripples
produced in waves or oscillating water. Crests of symmetrical ripples tend to be relatively straight, but may bifurcate (or fork).
symmetrical ripples
Crests of these ripples may be straight, sinuous, or lobe-like (lingoid ripples), depending on water velocity.
assymetrical
Crests of these ripples tend to be relatively straight, but may bifurcate (or fork).
symmetrical ripples
Polygonal cracks formed in drying mud, indicating subaerial exposure. The mud polygons between the cracks may be broken up later by water movement, and redeposited as intraclasts (particularly ir. lime muds).
mud cracks
Stratification (or layering) is the most obvious feature of sedimentary rocks. The layers (or strata) are visible because of differences in the color or texture of adjacent beds.
Internal Bedding structures
__________________ is the most obvious feature of sedimentary rocks. The ________________ are visible because of differences in the color or texture of adjacent beds.
Stratification (or layering)
layers (or strata)
Strata thicker than 1 cm are commonly referred to as _________; thinner layers are called____________ or ___________; the upper and lower surfaces of these layers are called _____________.
beds
laminations or laminae
bedding planes
Most bedding is ____________ because the sediments from which the sedimentary rocks formed were originally deposited as horizontal layers.
horizontal
It is the result when a sediment-laden current (such as a turbidity current) begins to slow down. The grain size within a graded bed ranges from coarser at the bottom to finer at the top. Hence, graded beds may be used as “up indicators”.
graded bedding
If the individual inclined layers are thicker than 1 cm, the cross-stratification may be referred to as cross-bedding. Thinner inclined layering is called cross-lamination.
cross bedding
If the individual inclined layers are thicker than 1 cm, the cross-stratification may be referred to as ________________. Thinner inclined layering is called ____________.
cross-bedding
cross-lamination
These are bedding plane structures preserved on the bottom surfaces of beds. They generally result from the filling in of impressions made into the surface of soft mud by the scouring action of the current, or by the impacts of objects carried by the current.
sole marks
Produced as “tools” (objects such as sticks, shells, bones, or pebbles) carried by a current bounce, skip, roll, or drag along the sediment surface. They are commonly preserved on the lower surfaces of sandstone beds as thin ridges. are generally aligned parallel to the direction of current movement.
Tool marks
Produced by erosion or scouring of muddy sediment, forming “scoop-shaped” depressions. They are commonly preserved as bulbous or mammillary natural casts on the bottoms of sandstone beds. Because of their geometry, can be used to determine paleocurrent directions.
flute marks (also called flute casts)
These structures result from the activities of living organisms, including both direct and indirect biological processes. The organisms may be animals which walk on or burrow into the sediment, they may be plants with roots which penetrate the sediment, or they may be bacterial colonies which trap and bind the sediment to produce layered structures.
organic sedimentary structures
Disruption of sedimentary layers by organisms such as burrowing animals, leading to a mixed or homogenized sediment.
bioturbation
Indications of biological activity, such as footprints, burrows, or feeding marks preserved in sediment.
trace fossils
Organic buildup of skeletal material from corals or other marine organisms, creating significant depositional features.
reef structures
