GEOLOGY LECTURE 1 Flashcards
It is the study of earth
Geology
It is concerned with the earth and the rocks of which it is composed, the processes by which they were formed during geological time, wnd the modelling of the earth’s surface in the past and at the present day.
The science of geology
This term is used for those materials of many kinds which form the greater part of the relatively thin outer shell, or crust of the earth.
Rocks
Rocks are made up of ________ units
Small crystalline
Rocks are made up of small crystalline units. What are these crystalline units called?
Minerals
In geology this is a hard material.
Rocks
In geology, these are either sediments which have not yet become rock-like or a granular residue from a rock that has completely weathered.
Soil
It is an interdisciplinary field which uses geoscience to solve engineering and environmental problems.
Geology engineering
It is a branch of geology concerned with the study of Strata and stratification.
Stratigraphy
What are the 2 sub-fields of stratigraphy.
LithoStratigraphy and Biostratigraphy
The visible layering of bedding on strata is due to?
Physical Contrast in rock type
These are the changes in environments of deposition.
Facies
This is a basic concept of stratigraphy that states: in an undeformed stratigraphic sequence, the oldest strata occur at the base of the sequence.
Law of Superposition
It is the classification of bodies of rock based on the observable lithologic properties of the strata and their relative stratigraphic positions.
Lithostratigraphy
This studies the changes in the relative proportions of trace elements and isotopes within and between lithologic unit.
Chemostratigraphy
This type of LithoStratigraphy documents the often cyclic changes in the relative proportions of minerals, grain size, thickness of sediment layers(varves) and fossil diversity with time.
Cyclostratigraphy
This is the study of strata based on fossil evidence in the rock layers.
Biostratigraphy/Paleontologic stratigraphy
What was biologic stratigraphy based on?
William smith’s Principle of faunal succession
This is a branch of geology concerned with establishing the absolute ages of strata.
Chronostatigtaphy
This curve attempts to define a global historical sea-level curve according to inferences from worldwide stratigraphy patterns.
Vail curve
What are the 3 rock types?
Igneous, Sedimentary, and Metamorphic rocks.
This is the process that transforms and moves rocks.
Rock-Cycle
How many minerals have been identified?
3500
What are the two types of igneous rocks?
Intrusive and extrusive igneous rocks
What type of igneous rocks are plutons made out of?
Intrusive igneous rocks
What are the largest types of plutons called?
Batholiths
Cooling speed of igneous rocks with large mineral crystals.
Slow
What kind of igneous rocks are formed from lavas in volcanoes?
Extrusive igneous rocks
The word igneous is from latin that means fire-formed.
What is the most common type of igneous rock?
Basalt
What is the type of igneous rocks formed from magma?
Intrusive igneous rocks
What are rocks from deep magma called?
Plutonic
What are the two best known igneous rocks?
Basalt, and Granite
What are rocks that are rich in Magnesium and Iron called?
Mafic rock
These rocks are rich in Feldspar and Quarts.
Felsic rocks
This is the cementing, compacting, and hardening of sediments to form sedimentary rocks.
Lithification
It is a zone in rocks where movement occurred
Faults
A fault caused by pulling strength and downward slip
Normal faults
One block is pushed over the other due to compression.
Reverse fault
Horizontal movement occurs. Because of the high friction of fault places, movement occurs not gradually, but in short events, here are earthquakes occur
Strike-slip fault
This is formed in relief of stress which has accumulated in rocks.
Fractures
These are fractures on which relative displacement of the two sides of the break has taken place.
Fault
These are fractures where no displacement has occurred.
Joint
This is a fold downwards
Syncline
This is a fold upwards
Anticline
If the movements continue after folding a fold can break, and becomes a ________.
Thrust
An arched fold in which the two limbs dip away from one another is called __________
Antiform
This is antiform but the rocks that form the core are older than the outer strata.
Anticline
A fold in which the limbs dip towards one another is a _________
Synform
This is a synform but the strata forming the core of the fold is younger than those below them
Syncline
A Strata that has behaved as a brittle material.
Competent
A strata which flowed as ductile material.
Incompetent
This term is used for structures produced by materials such as rock salt or mobile granite which have moved upwards and pierced through the overlying strata.
Diapir
This is a group of parallel joints.
Joint sets
Two or more joint sets that intersect
Joint system
Developed from the drying and freezing, resultant shrinkage of sedimentary deposits.
Shrinkage-joints
Joint parallels the axis of the fold and are concentrated in the fold hinge where tension is at greatest.
Tension joints
Joints that cross many bedding planes are called ________
Master joints
This is the general term for the Land areas continually being reduced and their shapes modified by weathering and erosion.
DENUDATION
This is the breakdown of minerals into new compounds by the action of chemical agents, although they act slowly, produce noticeable effects especially in soluble rocks.
Decomposition or chemical weathering
The break down of rocks into smaller particles by the action of temperature, by impact from raindrops and by abrasion from mineral particles carried by the wind.
DISINTEGRATION OR MECHANICAL WEATHERING
Decomposition and Disintegration of the ground that are directly associated with the activities of animals and plants.
Biological Weathering
What are the agents of erosion?
Rivers, wind, moving ice, and water waves.
This is the term for the weathered material.
Detritus
The removal of material.
Erosion
This is the scientific study of earth surface processes, including erosion, deposition and formation of landforms and sediments.
Geomorphology
The breaking down and changing of rocks as a result of exposure to the environment
Weathering
In what climate chemical reactions are most intense?
When the climate is most wet and hot
The altering of rocks as a result of exposure to different substances.
Decomposition
Processes commonly involved with Decomposition
SOLUTION, OXIDATION, REDUCTION, HYDRATION, HYDROLYSIS, LEACHING, AND CATION EXCHANGE,
This layer of rock ranges in depth from only a few centimeters to a meter or more. It has a mixture of inorganic particles and vegetable humus and high porosity.
Top-soil
In this layer is a mixture of soil with rock fragments, with decreasing organic content, and then into weathered rock and finally unweathered rock
Sub-soil
What are the terms for layers of soil in Pedology?
A-horizon, B-Horizon, C-Horizon
What is the C-Horizon?
Rock at depth
What is the A-Horizon?
Soil
B-Horizon
Sub-soil
The terms A-horizon, B-horizon, C-horizon are used in?
Pedology
A vertical column showing the sequence of soil layers.
Soil-profile
Dissociation of minerals into ions, greatly aided by the presence of CO2 in the soil-profile, which forms carbonic acid (H2CO3) with percolating rainwater
Solution
The combination of oxygen with a mineral to form oxides and hydroxides or any other reaction in which the oxidation number of the oxidized elements is increased
Oxidation
The release of oxygen from a mineral to its surrounding environment: ions leave the mineral structure as the oxidation number of the reduced elements is decreased
Reduction
Absorption of water molecules into the mineral structure. This normally results in expansion, some clays expand as much as 60%, and by admitting water hasten the processes of solution, oxidation, reduction and hydrolysis.
Hydration
Hydrogen ions in percolating water replace mineral cations: no oxidation-reduction occurs.
Hydrolysis
The migration of ions produced by the above processes. The mobility of ions depends upon their ionic potentials.
Leaching
Absoption onto the surface of negatively charged clay of positively charged cations in solution, especially Calcium, hydrogen, Potassium, and Magnesium.
Cation Exchange
In limestone the process of Decomposition is dependent on?
Feeble acids such as CO2 and SO2
These are Ground surface that show depression that may continue downwards as irregular channels.
Pipes
Vertical joints that are widened by solution.
Grikes
Continued solution to grikes that may lead to the formation of _________.
Swallow Hallows
Rough Shafts which communicate with solution passages at lower levels along which water flows underground.
Shallow holes
Where are swallow holes often situated?
At the intersection point of the vertical joints.
What causes Disintegration?
The effects of changing temperature on rocks.
This occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.
Freeze-thaw
Types of Disintegration
Frost action, Exfoliation, abrasion, and Root wedging
The freezing/thawing of ice cracks rocks
Frost action
Grinding of rock against rock
Abrasion
Plant roots growing into rocks
Root Wedging
Altering hot/cold cracks rocks
Exfoliation
Processes of Disintegration
Mechanical unloading, Mechanical loading, thermal loading, wetting and drying, crystallization, Pneumatic loading.
Vertical expansion due to the reduction of vertical load by erosion. This will open existing fractures and may permit the creation of new fractures.
Mechanical unloading
Impacts on rock, and abrasion, by sand and silt size wind-borne particles in deserts. Impact on soil and weak rocks by rain drops during intense rainfall storms.
Mechanical loading
Expansion by the freezing of water in pores and fractures in cold regions, or by the heating of rocks in hot regions. Contractions by the rolling of rocks and soils in cold regions
Thermal loading
Expansion and contractions associated with the repeated absorption and loss of water molecules from mineral surfaces and strictures
Wetting and Dryinf
Expansion of pores and fissures by _________ within them of minerals that were originally in solution. Expansion is only severe when ___________ occurs within a confined space
Crystallization
The repeated loading by waves of air trapped at the head of fractures exposed in the wave zone of a sea cliff.
Pneumatic loading
These living organisms grow on essentially bare rock surfaces and create a more humid chemical microenvironment.
Lichens and Mosses
The physical interaction of flowing water and the natural channels of rivers and streams. This includes the motion of sediments and erosion or deposition on river beds
Fluvial Process
What bodies of water are Fluvial processes associated.
Rivers and streams and landforms and deposits created by them.
The physical interaction of Stream or rivers that are associated with glaciers, ice sheets, or ice caps.
Glaciofluvial or Fluvioglacial
How many ways can erosion of moving water happen?
2
Sediments in rivers are transported as?
Bedload or suspended load
This is the coarser fragments which move close to the bed.
Bedload
These are finer fragments carried in the water.
Suspended load
A specific velocity at which the grains start to move.
Entrainment Velocity.
In rivers, areas where more particles are dropped.
Alluvial or flood plains
In rivers, these are called the dropped particles
Alluvium
In earth science, this is the action of surface processes that removes soil, rock, or dissolved material from one location on the earth’s crust and then transports it to another location.
Erosion
Agents of erosion inclusion:
Rainfall
Bedrock wear in rivers
Coastal erosion by the sea and waves
Glacial plucking, abrasion, and scour
Areal flooding
Wind abrasion
Ground water processes
Mass movement processes in steep landscapes like landslides and debris flows.
How many times did human activities increase the rate of erosion globally?
10-40 times
What are the two primary causes of land degradation?
Water and wind erosion
Is the geological process in which sediments, soil and rocks are added to a landform or landmass. Can also refer to the buildup of sediments from organically derived matter or chemical processes.
Deposition
When forces responsible for sediment transportation are no longer sufficient to overcome the forces of gravity and friction, creating a resistance to motion.
Null-point hypothesis
The geomorphic movement by which soil, sand, regolith, and rock move downslope typically as a solid, continuous or discontinuous mass, largely under the force of gravity, frequently with characteristics of flow as in Debris flows and mudfloes
Mass wasting, slope movement, mass movement
Is the formation, movement and recession of glaciers.
Glaciation
Are landforms created by the action of glaciers.
Glacial landform
How many of the world’s land area do glaciers cover?
10% or 14.9 million km²
What are the 2 methods that erosion by glaciers occurs?
Abrasion and Quarrying
This is the underlying material under the rocks.
Bedrock
Is the process by which blocks of bedrock are removed by overriding ice
Quarrying
An example of quarrying
Roches Moutonnées
In glaciers, is the process in which glaciers add sand, minerals and other materials to the bedrock underneath.
Deposition
A rounded hill or mound formed by the streamlined movement of glacial ice across rock debris.
Drumlin
A depositional feature of high- relief forms consisting of mounds, ridges and knobs, some of which are doughnut-shaped
Hummocky moraines
Bow-shaped ridges of varying heights and lengths
Recessional moraines, Cross-valley, ribbed, De Geer, washboard
Single, prominent ridges marking the limit of glacial advance.
Terminal moraines
Consists of an irregular blanket of till deposited under a glacier
Ground moraine
Is an unsorted, unstratified glacial sediments
Glacial till
The mixture of glacial till.
Clay, silt, sand, pebbles, cobbles, and boulders
Can originate from the surface, inside or at the base of glaciers. Streams that can become an interconnecting network of shallow channels that carry and deposit gravel and sand.
Meltwater
The process of breaking down and dispersing particles by wind movement
Wind erosion
The process of the wearing away of a solid object due to the impact of particles carried by the wind.
Wind abrasion
Rocks with flat, wind-abraded surface are reffered to as __________.
Ventifacts
The boundary of the continent/island. Describes the area where the land meets the sea or the ocean.
Coastline
The boundary of the land.
Shoreline
A landform along the coast of an ocean or sea.
Beach
Tides that are higher than normal.
Spring tides
Tides that are lower than normal.
Neap tides
The horizontal movement of water or air.
Currents
What are waves often called.
Shakers
Parts of a beach
Swash zone, Beach face, Wrack line, berm
Is alternately covered and exposed by wave run-up
Swash zone
Sloping sections below berm that is exposed to the swash of the eaves
Beach face
The highest reach of the daily tide where organic and inorganic debris is deposited by eave action.
Wrack line
A nearly horizontal portion that stays dry except during extremely high tides and storms may have sand dunes.
Berm
Layers of soil or sediments on the beach.
Beach profile.
A form of coast where the action of marine waves has formed steep cliffs that may or may not be precipitous.
Cliffed coast also called abrasion coast
The continuous action of marine waves on the coastline.
Abrasion
From when a river carrying sediments reaches another body of water.
Deltas
Deltas form when river reaches:
-A body of standing water, such as a lake, ocean, reservoir.
-Another river that cannot remove sediments quickly enough to stop delta formation.
-Inland region where the water spreads out and deposits sediments.
A bar of rock, sand, coral, or similar material, lying beneath the surface of water.
Reef
Built by microorganisms or organisms that don’t grow a skeletal framework.
Mounds
Caused by on shore winds pushing water on to the coastline on the left side of the hurricane as it spins counter clockwise.
Storm Surge
They are immense sea waves, which are produced by underwater events such as earthquakes, mud slide, and volcanic eruptions.
Tsunamis
It is derived from many sources, most come from rainfall and melting snow.
Ground water or meteoric ground water.
The passage of water through the surface of the ground.
Infiltration
It is described as the downward movement of water to the saturated zone at depth.
Percolation
The word used to describe precipitation that has infiltrated into the ground and travels down until it reaches the impervious stratum where it is stored as groundwater.
Ground water
Where is groundwater stored?
In the pores present in the geological formations.
The process in which water from saturated ground zones moves towards rivers, lakes, and seas.
Ground-water flow
The circulation of water.
Hydrological Cycle
The seas and oceans contain approximately _________ of all the water presently involved in the cycle.
97%
Frozen soil
Permafrost
The level of standing water in the ground.
Watertable
Ground through which water flows at rates of significance to engineering works
Aquifers
Are described as unconfined if their upper surface is ground level and confined if they are covered or confined by less permeable material.
Aquifers
Aquifers whose upper surface is ground level.
Unconfined
Aquifers that are covered or confined by less permeable materials.
Confined
Ground through which water does not flow at such a rate.
Aquitard
A surface ( bedding,fault,etc.) that separates ground of different hydrogeological character.
Hydrogeological boundary
Where does infiltration readily occur?
Open fractures and joints in exposed rock.
What happens when rainfall exceeds the infiltration capacity?
Results to flooding
An underground boundary between the soil surface and the area where groundwater saturates spaces between sediments and cracks in rock.
Water Table
Rocks and soils that transmit water with ease through their pores and fractures.
Aquifers
Rock and soils that are difficult to transmit water.
Aquicludes
A body of rock and/or sediments that holds groundwater.
Aquifers
A geological formation which is impermeable to the flow of water.
Aquicludes
A zone within the earth that restricts the flow of groundwater from one aquifer to another.
Aquitard
An impermeable geological formation which is neither porous nor permeable.
Aquifuge
Aquitards comprises layers of
Clay or non-porous rock with low hydraulic conductivity.
Typical aquifers are:
Gravel, sand, sandstone, limestone, and fractured igneous and metamorphic rocks.
Typical Aquicludes are:
Clay, mudstones, shales, evaporite, and unfractured igneous and metamorphic rocks.
How does soils transmit water?
Through their pores
How do most rocks transmit water?
Through their pores and fractures.
one where the water table occurs within the aquifer layer. It is also called a water table or Phreatic aquifers.
Unconfined aquifers
An aquifer confined between two impermeable beds such as aquifuge, aquiclude, etc.
Confined Aquifer
The water in the confined aquifer will be under greater pressure. Hence, the water level shown by the piezometer is always higher than the top level of the confined aquifer.
The recharge of confined aquifer occurs at a place where it exposes to the ground surface
The pores between small clay particles.
Micropores
Larger pore spacing between larger particles, such as sand.
Macropores
The gap between solid particles, which contains water and air.
Soil Porosity
A measure of the ease of flow of a fluid through a porous solid.
Permeability
It is the material left behind by glaciers
Moraines
The water in the pores of a soil
Pore pressure
The pressure within a porewater, this refers to the pressure of groundwater held within a soil or rock, in gaps between particles.
Pore water pressure
• Pore water pressures below the phreatic level of the groundwater are measured with PIEZOMETERS
The magnitude of pore water pressure is dependent on:
• The depth below the water table.
• The conditions of seepage flow
Pore water pressure at depth will be _______ since the void space between the solid particles is continuous.
Hydrostatic
This is denoting the equilibrium of liquids and the pressure exerted by liquid at rest
Hydrostatic
The tool is used to measure pore water pressured below the phreatic level of the groundwater?
Piezometers
A device used to measure pore water pressure in the ground by measuring the height to which a column of fluid rises against gravity
How is the pore pressure determined in the Vadose zone?
By Capillarity
The pore water pressure in the Vadose Zone is also referred to as?
Tension, Suction, Matric pressure
Matric pressures are measured with _________.
Tensiometers
This tool operates by allowing pore water to come into equilibrium with a reference pressure indicator through a permeable ceramic cup placed in contact with the soil
Tensiometers
This is defined as the difference between the overburden pressure minus the measured pore pressure
Effective pressure
or
Difference pressure
•Difference pressure Governs the compactions process in sedimentary rocks.
