final test Flashcards
breaking of rocks into smaller pieces:
Weathering
Types of Weathering:
Mechanic Weathering
Chemical Weathering
without a change in their composition.
Mechanic Weathering
Water freezes in a crack of a rock.
Frost Wedging
tectonic forces lift deeply buried rocks close to the surface.
Pressure-release
grinding and rounding of rock surfaces by friction.
Abrasion
crack in the rock is expanded by plant roots or broken by animals and human activities.
Organic Activity
temperature changes rapidly, causing the surface of the rock to heat or cool.
Thermal expansion and Contraction
change rock’s composition.
Chemical Weathering
rock dissolves in water.
Dissolution
mineral reacts with water to form a new mineral
Hydrolysis
mineral decomposes when it reacts with oxygen
Oxidation
removal of rock particles. It is due to some agents such as water, wind, waves, rain and ice.
Soil erosion
removal of rocks and soil.
Erosion
There are three ways of load to be transported:
In Solution (Dissolved Load)
In Suspension (Suspended Load)
Scooting or rolling Along the Bottom (Bed Load)
acquired by dissolving rocks along the stream’s course.
In Solution (Dissolved Load)
during floods, larger particles are also transported.
In suspension (Suspended Load)
coarser particles that move along the bottom of the stream by rolling, sliding.
Scooting or Rolling Along the Bottom (Bed Load)
Types of Erosion:
Splash erosion
Sheet erosion
Rill erosion
Gully erosion
is the movement of rocks, soil, and regolith downward
It occurs on both terrestrial and submarine slopes.
It is called slope movement.
Mass Wasting
Mass wasting is triggered and controlled by the following factors:
Water
Over Steepened Slopes
Vegetation Removal
Earthquakes
If soil and regolith dominate
Debris, Mud or Earth
Common form of movement on very steep slopes
Rocks
When movement involves the free-fall of detached individual pieces of any size.
Fall
when material remains fairly coherent and moves along a well-defined surface.
Slide
when a material moves downslope as a viscous fluid and most are saturated with water and typically move as lobes or tongue.
Flow
Downward sliding of a mass of rock or unconsolidated material moving as a unit along a curved surface.
Slump
Rapid slide of a mass of rock downslope.
Rockslide
Involves a flow of soil and regolith containing a large amount of water and also called mudflows or lahar if it occurs on slopes of volcanoes.
Debris Flow
Quite viscous so it moves slower than debris flow and a special type is called liquefaction.
Earthflow
gradual downhill movement of soil and regolith
Creep
occurs in a zone above the permafrost called the active layer, which thaws in summer and refreezes in winter.
Solifluction
Earth’s interior:
Crust
Mohorovicic
Mantle
- Upper layer
- Lower Layer
Gutenberg
Outer core
Lehman
Inner core
Thinnest and the outermost layer of the Earth.
Extends from the surface to about 32 km below
Thickness extends to 72 km
Consist of 2 layers: upper layer (composed of granite and found in the continental crust only); lower layer ( composed of basalt and found under continents and oceans)
Composed of continental and oceanic crust
Crust
Mostly 30-40 km in thickness
Found under land masses
Made of less dense rocks such as granite
Continental Crust
- 7-10 km in thickness
- Found under ocean floor
- Made of dense rocks
- Heavier than continental crust
Oceanic crust
beneath the crust
Extends about 2900 km from the earth’s surface
Makes up to 80 % of the earth’s total volume and about 68 % of its total mass
is solid because P and S waves pass through it
Lower part of the mantle consist of more iron than the upper part
Lower mantle is denser than the upper portion
Mantle
It consist of two different layers:
Litosphere- the rigid zone which is the upper mantle
Asthenosphere
Mesosphere- lower layer
Mantle
region separates the crust and the mantle.
named after Andrija Mohorovicic, a scientist from Yugoslavia
Mohorivicic
It is 2900 km below the earth’s surface
It is 2250 km thick
Has temperature reaches up to 2000 degrees Celsius
It is molten based on the seismic data analysis and magnetic field strength of the earth
Thought by scientists to be liquid
Outer Core
Has a radius of 1300 km
Has a temperature reaches up to 5000 degrees Celsius
Boundary between the outer core and inner core was discovered by Inge Lehman
Inner core
process of mineral assemblage and texture variation that results from the physical-chemical changes of solid rock.
Metamorphism
is usually characterised by low temperature and high pressure conditions.
Regional metamorphism
usually occurs under higher temperature conditions.
Contact metamorphis
when sediments are buried deeply enough that the heat and pressure cause minerals to begin to recrystallize
Burial metamorphism
the presence of magma near the surface of the Earth leads to the circulation of hot water through the upper crust.
Hydrothermal metamorphism
mainly along the plate boundaries, the zones that are not stable.
Faulting and Folding
When two forces push towards each other from opposite sides.
Large-scale folds are found mainly along destructive plate boundaries.
Folding
is the fracturing and displacement of more brittle rock strata along a fault plane.
Faulting
A break in rock
Fault
line of fault which appears on land surface.
These lines are often lines of weakness
Fault line
line of fault which appears on land surface.
These lines are often lines of weakness
Fault line
Types of Faulting:
Normal Fault
Reverse Fault
Tear Fault
the block above the fault has moved downward
Normal Fault
the hanging wall moves up relative to the footwall.
Reverse Fault
the motion is predominantly horizontal.
Tear Fault
the motion is predominantly horizontal.
Tear Fault
most common type of mountain. The world’s largest mountain ranges are fold mountains.
Fold Mountains
are formed when two plates collide head on, and their edges crumbled.
Fold mountains
The upward folds are known as
anticlines
the downward folds are
synclines
Examples of fold mountains include:
Himalayan Mountains in Asia
Alps in Europe
Andes in South America
Rockies in North America
Urals in Russia
when cracks in the earth’s crust force some materials or blocks of rock up and others down. The earth’s crust fractures (pulls apart).
Fault-block Mountains
Examples of fault-block mountains include:
Sierra Nevada mountains in North America
Harz Mountains in Germany
result of a great amount of melted rock (magma) pushing its way up under the earth crust.
The uplifted area created by rising magma is called a dome
Dome Mountains
formed by volcanoes. Formed when magma deep
erupts, and piles upon the surface.
Volcanic Mountains
when magma breaks through the earth’s crust.
Lava
Examples of volcanic mountains include:
Mount St. Helens in North America
Mount Pinatubo in the Philippines
Mount Kea and Mount Loa in Hawaii
formed by erosion.
Plateau Mountains
large flat areas that have been pushed above sea level.
Plateaus
Examples of plateau mountains:
The mountains in New Zealand
Continental Jigsaw Puzzle
Fossils Match across the Seas
Rocks and Types Structure Match
Ancient Climate (Coal Deposits)
Continental Drift Theory:
Convergent Boundaries
Divergent Boundaries
Transform Boundaries
The Plate Tectonic Theory
Convection Current Hypothesis
Slab-push and Slab-pull Hypothesis
Hot plumes Hypothesis
Driving Mechanism
Continental Drift Theory
Evidence #1. Continental Jigsaw Puzzle
Evidence #2. Fossils Match across the Seas
Evidence #3. Rocks and Types Structure Match
Evidence #4: Ancient Climate (Coal Deposits)
States that the Earth’s solid outer crust, the lithosphere, is separated into plates.
The Plate Tectonic Theory
two plates are colliding.
Where oceanic crust meets ocean crust
Where oceanic crust meets continental crust
Where continental crust meets continental crust
Convergent boundaries
two plates are moving apart.
On land
Under the sea
Divergent boundaries
plates slide passed each other.
Transform boundaries
The soul of Sea Floor Spreading theory
The heat source for these currents is heat from Earth’s core and from the mantle itself.
Hot columns of mantle material rise slowly.
At the top of the asthenosphere, the hot material spreads out and pushes the cooler material out of the way.
This cooler material sinks back into the asthenosphere.
Convection currents like these have been moving inside Earth for more than 4 billion years.
Convection Current Hypothesis
are thought to be the major forces driving the motion of oceanic plates.
Slab-push and slab-pull Hypothesis
is caused by the potential energy gradient
Ridge push
is caused by the negative buoyancy of the subducting plate.
Slab pull
postulates that this melt rises to the surface and erupts to form “hot spots”.
Hot Plumes Hypothesis
envisages the feeder structures to be fixed relative to one another,
The hypothesis thus predicts that time-progressive chains of volcanoes.
Hotspot volcanic chains
professor of geology at Princeton University in the 1960’s
played a key role in the development of the Theory of Plate Tectonics.
He and his crew conducted sonar test to map the seafloor, then found in his new hypothesis of Seafloor Spreading.
Harry Hess
This document was an important contribution to the development of Plate Tectonics.
History of Ocean Basins
means that the scientists could see that the magnetic pull had changed
Magnetic striping
science of determining the relative order of past events without necessarily determining their absolute age.
Relative dating
study of layered sedimentary rocks.
Stratigraphy
This section discusses principles of relative time used in all of geology:
Principle of Superposition
Principle of Original Horizontality
Principle of Lateral Continuity
Principle of Cross-Cutting Relationships
Principle of Inclusions
Principle of Fossil Succession
the layers on the bottom are the oldest and layers above them are younger.
Principle of Superposition
Layers of rocks deposited from above are originally laid down horizontally.
Principle of Original Horizontality
Layers of rocks deposited from above are originally laid down horizontally.
Principle of Original Horizontality
Within the depositional basin, strata are continuous in all directions
Principle of Lateral Continuity
Deformation events like folds, faults and igneous intrusions that cut across rocks are younger than the rocks they cut across.
Principle of Cross-Cutting Relationships
When one rock formation contains pieces of another rock, the included rock is older than the host rock.
Principle of Inclusions
Evolution has produced a succession of unique fossils that correlate to the units of the geologic time scale.
Assemblages of fossilsgroups of several unique fossils occurring together.
Principle of Fossil Succession
occurs when sedimentary rock is deposited on top of igneous and metamorphic rocks.
Unconformities
Types of unconformity:
Disconformity
Nonconformity
Angular unconformity
break or stratigraphic absence between strata
Disconformity
sedimentary strata are deposited on crystalline rocks.
Nonconformity
sedimentary strata that have been deformed by tilting, folding, and/or faulting.
Angular unconformity
Process of determining an age on a specified chronology
scientists prefer the terms chronometric or calendar dating, as use of the word “absolute” implies an unwarranted certainty of accuracy.
Radiometric Dating
Absolute Dating
Often called radioactive dating, is a technique used to determine the age of materials
Radiometric Dating
is a method for determining the age of an object containing organic material by using the properties of radiocarbon.
Carbon Dating
Published the first geologic time scale that included absolute dates in 1913
published the world-renowned book The Age of the Earth in which he estimated Earth’s age to be at least 1.6 billion years.
Arthur Holmes
“calendar” for events in Earth history.
It subdivides all time into named units of abstract time: (in descending order of duration)
Eons
Eras
Periods
Epochs
Ages
Geologic time scale
One of the most widely used standard charts showing the relationships between the various intervals of geologic time which is maintained by the International Commission on Stratigraphy (ICS).
International Chronostratigraphic Chart
Additional information: What era are we living in today?
Phanerozoic eon
Cenozoic era
Quaternary period
Holocene Epoch (Recent epoch)
preserved remains, or traces of remains, of ancient organisms.
they are rocks.
Fossils
Types of Fossils
Body Fossils
Molds and Casts
Per mineralization and Petrification Fossils
Footprint and Trackways
Fossilized Feces
entire remains of prehistoric organisms
bones and teeth – are the most common types of fossils.
Body Fossils
is an imprint left by the shell of a hard skeleton on surrounding rock.
may be internal or external.
Molds
Replicas of molds
Casts
fossils form in the original shape of the organism, but the composition is different, and it is heavier.
Per mineralization.
organic matter is entirely replaced by minerals and turns to stone.
Petrification fossils
Footprints, trackways, trails and burrows through mud sometimes harden and become fossils known as trace fossils.
These give information about how animals behaved when they were alive.
Footprints and Trackways
several footprints together.
Trackways
also known as dung-stone
give clues to where certain animals lived and what they ate.
are rare because feces usually decay quickly.
The most common coprolites are of sea organisms, particularly fish and reptiles.
Fossilized Feces
