EARTH SCIENCE Flashcards
AGE OF EARTH
4.543 billion years old
a collective layer of gas that envelopes the Earth.
Atmosphere
Earth’s four major spheres
Atmosphere
Hydrosphere
Biosphere
Geosphere
(1) It shields the Earth and its inhabitants from harmful ultraviolet (UV) radiation from the Sun;
(2) it maintains the warmth of the Earth’s surface; and
(3) it contains all of the essential gases needed to support life.
Atmosphere
refers to the bodies of water consisting of freely flowing bodies of water found on the surface of the Earth
Hydrosphere
refers to the narrow band on the Earth’s surface where all biological life resides.
Biosphere
This sphere covers nearly 71% of the Earth’s surface.
Hydrosphere
the largest out of all the spheres, extending from the surface of the Earth down to its center.
Geosphere
Layers of Earth Based on Compositional Differences
Crust
Mantle
Core
This is the thinnest and outermost layer of the Earth.
Crust
two types of crust
the continental and oceanic crust.
younger and denser type of crust.
oceanic crust.
comprises most of the Earth’s volume
Mantle
The boundary between the crust and mantle
Mohorovičić discontinuity
core begins at the mantle-core boundary
Gutenberg discontinuity
divided into the upper and lower mantle, separated by
Repetti discontinuity.
its composition comprises a Fe-Ni (iron and nickel) alloy.
Core
Layers of Earth Based on Physical Properties
Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core
thick and brittle layer comprising the entire crust and uppermost layer of the upper mantle.
Lithosphere
Contrary to popular belief, it is not a “sea of molten rock.” The upper mantle comprises an Mg- and Fe-rich rock called
peridotite.
mechanically weak layer consisting of the lower portion of the upper mantle, extending to 660 km.
Asthenosphere
-comprised of the lower mantle
-is much stronger and flows with more resistance. Because of the immense pressure from the overlying layers, the strength of this layer increases with depth.
Mesosphere
The dominant rock type in this layer (Mesosphere) is a silicate rock called
perovskite.
Layer the only one made out of liquid
Outer Core
Core’s flow of liquid metals is responsible for the
Earth’s magnetic field
The outer-inner core boundary is also known as
Lehmann discontinuity.
To be considered a mineral:
Naturally-occurring
Inorganic
Homogeneous solid
Has definite chemical composition
Ordered crystalline structure
It refers to the wavelengths of light reflected by the minerals. While it can be tempting to identify a mineral based on its-, it is the least valuable property because many minerals can occur in different colors.
Color
It describes how light is reflected from the mineral’s surface.
Luster
This refers to the shape of each crystal or an aggregate of crystals.
Crystal Habit or Shape.
his is the color of the mineral when it is powdered.
Streak
This refers to how resistant a mineral is to scratching.
Hardness
refers to the tendency of a mineral to break along preferred planes called zones of weakness.
Cleavage or Fracture
This refers to the ratio between a mineral’s weight and the weight of a specific volume of water
Density or Specific Gravity
This describes how well a mineral handles stress, such as breaking, crushing, bending, or tearing.
Tenacity
This refers to how well light travels through a mineral.
Diaphaneity
This describes the magnetic property of a mineral
Magnetism
This describes a mineral’s reaction to a strong acid
Effervescence
Geologist licking rocks
Odor and Taste
-most common mineral group
-most abundant blocks
silicates
less abundant mineral group
non-silicates
are formed when molten material cools and solidifies.
Igneous Rocks
When igneous rocks form below the surface of the Earth
intrusive igneous or plutonic rocks
When igneous rocks form on the surface
extrusive igneous or volcanic rocks.
are formed from loose material called sediments that have been eroded in weathering and then buried and compacted in a process called diagenesis.
Sedimentary Rocks
are classified based on the characteristics of their clasts, such as size, angularity/roundedness, and sorting.
Clastic Sedimentary Rocks
Chemical sedimentary rocks are formed when water evaporates, leaving behind dissolved minerals. Common examples include halite or rock salt, gypsum, flint, chert, travertine, umber, and limestone rocks.
Non-clastic Sedimentary Rocks
When a rock is subjected to certain chemical (addition or removal of chemicals) or physical (change in temperature or pressure) processes that alter its chemical composition, mineralogy, and/or texture
Metamorphic Rocks
Type of metamorphic tock that is a rock is the result of deformation
foliated rocks.
Type of metamorphic rock usually develop in environments where deformation is minimal and other factors, such as chemically-active fluids, play a larger part in altering the rock.
Nonfoliated rocks
geological process in which earth materials are weathered and transported
Erosion
Land and water forms in this environment can be found on land and usually involve freshwater.
Terrestrial Environments
represent the interface between land and sea. It is here where freshwater meets with seawater.
Transitional Environments
These environments can be found in the open waters, from the shallow depths to the deepest portions of the ocean.
Marine Environments
branch of geology that studies rock layers, beds, or strata
Stratigraphy
the layers on the bottom are the oldest, while the layers above are younger.
Law of Superposition
Each stratum extends laterally until it encounters a barrier or obstacle.
Law of Lateral Continuity
Strata are deposited horizontally.
Law of Original Horizontality
If a geologic body (like an intrusion) or discontinuity (like a fault) cuts across strata, it must be younger than the strata it cuts.
Law of Cross-cutting Relationships
igneous rock body that forms when magma cuts through sedimentary layers and solidifies before it reaches the surface.
intrusion
Father of English Geology
William Smith
Sedimentary strata may contain fossils of plants and animals in a definite and invariable sequence. Thus, the age of a stratum and another stratum in a different location can be correlated if they share the same fossil assemblage.
Principle of Faunal Succession
the “missing time” represented by the unconformity in a rock sequence.
hiatus
This type of unconformity is present when there is a missing stratum or strata in the sequence, usually due to a period of non-deposition or erosion.
Disconformity
When strata are disturbed by forces that cause folding, tilting, and/or faulting, they no longer appear horizontal. The surface is then exposed to erosion, and another set of sedimentary strata is soon deposited on top of the disturbed sequence.
Angular unconformity
This occurs when sedimentary strata are deposited on top of igneous or metamorphic rock bodies.
Nonconformity
identifying the age of strata in relation to other strata in a method called
relative dating
Determining the absolute age of a layer requires certain techniques collectively known as
absolute dating.
Radioactive isotopes are unstable (parent isotopes) and lose subatomic particles or energy over time in a process called
radioactive decay.
is the study of fossils linking concepts of geology and biology
Paleontology
This occurs when pores and open spaces in tissue (such as bone and wood) are filled with minerals precipitated from mineral-rich solutions such as groundwater.
An example of - at work is when silica precipitates inside the wood’s pores, creating petrified wood.
Permineralization
When organisms buried in sediment dissolve or decay away, it leaves behind a hollow space called - in the organism’s shape. If minerals eventually fill in this hollow space, a - is made.
mold and cast
These organisms are preserved when they fall into a viscous tree sap which hardens into -
amber
Soft-bodied organisms and delicate plant parts can be conserved via -. This happens when these organisms are buried in sediment and eventually dissolve, leaving behind a thin layer of carbon outlining the organism’s shape.
Carbonization
Organisms can also be exceptionally preserved when they are encased in ice
Freezing
can tell a lot about how an organism lived–how it moved, what it ate, and other types of behavior.
trace fossils
tool geologists use to classify and date rocks and fossils. Instead of numerical ages, time is divided into eons, eras, periods, epochs, and ages
The Geologic Time Scale
era; The formation of the Earth; magma ocean; intense bombardment of space bodies (“Late Heavy Bombardment”)
Hadean Eon
era; Life begins as prokaryotic bacteria; Blue-green algae start to produce oxygen in the atmosphere
Archean Eon
era; Multicellular life emerges
Proterozoic Eon
era; Multicellular life flourishes and diversifies (“Cambrian Explosion”)
Cambrian Period
era; “Age of Invertebrates”
Ordovician Period
era; Emergence of plants on land
Silurian Period
era; “Age of Fishes”; Towards the end, true amphibians emerged
Devonian Period
era; “Age of Amphibians”
Carboniferous Period
Amphibians diversified; large coal swamps formed
Mississippian
Emergence of reptiles
Pennsylvanian
era; Existence of Pangaea; the largest mass extinction in Earth’s history occurred towards the end (“The Great Paleozoic Extinction”)
Permian Period
era; Dinosaurs emerged; start of the Age of Reptiles; first true mammals (therapsids) emerged as well
Triassic Period
era; Dinosaurs dominated the Earth; the first birds emerged
Jurassic Period
era; first flowering plants emerged (angiosperms); marked the end of the Age of Reptiles with the Cretaceous-Tertiary Extinction (“K-T Extinction”)
Cretaceous Period
era; start of the Age of Mammals
Paleogene Period
era; Mammals and birds evolved into modern forms; hominids, the ancestors of humans, appeared towards the end
Neogene Period
Evidence of Continental Drift Theory
Continental Jigsaw Puzzle
fossils
Similar rock types and geologic features
ancient climates
New oceanic crust forms in the axis of this ridge system. Because of this, rocks become progressively older and thicker with sediment away from the axis.
seafloor spreading
7 Major Plates
African plate
Antarctic plate
Eurasian plate
Indo-Australian plate
North American plate
Pacific Plate
South American plate
Minor plates
Philippine Sea plate
Juan de Fuca plate
Cocos plate
Nazca plate
Scotia plate and
Arabian plate
are formed when two plates move apart relative to each other.
Divergent Plate Boundaries (Constructive Margins)
are the sites where plates move towards each other
Convergent Boundaries (Destructive Margins)
a collision or one plate going under the other
subduction process
When an oceanic plate converges with a continental plate
Oceanic-Continental Plates Convergence - Mariana Trench
occur when two continental plates move towards each other.
Continental-Continental Plates Convergence - Himalayan mountain range
Because continental crust is too thick and buoyant to be subducted, most crustal material is deformed and pushed up instead. This results in the accumulation of sediments and rocks along the margin, forming mountain belts in a process called
orogeny
when two oceanic plates collide.
Oceanic-Oceanic Plates Convergence - volcanic island arc or island arc.
two plates sliding past each other
Transform Plate Boundaries (Conservative Margins)
are linear breaks on the ocean floor that run perpendicular to oceanic ridges.
Fracture zones
occur when one block of earth slips past another block along surfaces called faults or fault planes and generates ground shaking.
Earthquakes
are waves that travel through the interior of the Earth.
Body Waves
These are the fastest seismic waves and can travel through solid, liquid, and gas. These waves push and pull the rocks in the direction the wave is traveling. They are also called compressional waves because of this behavior.
Primary Waves
These waves cause the rocks to shake up and down at right angles to the direction of the traveling wave. They are also called shear waves.
Secondary Waves
waves that can only travel on the surface of the Earth
Surface waves
These waves are responsible for shaking the ground horizontally and vertically in an S-like pattern.
Love Waves
These waves move in a rolling motion similar to ocean waves.
Rayleigh Waves
is the study of earthquakes.
Seismology
refers to the qualitative measurement of ground shaking at a particular location, depending on the damage to property, life, and nature.
intensity
the size of the earthquake.
Magnitude
The hanging wall moves down relative to the footwall in a normal fault.
Normal Faults
the hanging wall moves up relative to the footwall.
Reverse Faults
blocks move horizontally to one another due to shearing forces.
Strike-Slip Faults
ombining shearing and tensional or compressional forces would result in an
Oblique-Slip Faults
form of mass wasting where large amounts of earth move down a slope under the influence of gravity.
landslide
sudden sinking of the Earth’s surface due to the movement of the earth underneath.
Subsidence
sudden sinking of the Earth’s surface due to the movement of the earth underneath but occurs when sediments are saturated with water.
Liquefaction
geological process where hot molten rock from underneath the earth reaches the surface through an opening in the ground.
Volcanism
describes how the molten material was ejected, whether it was violent (explosive eruptions), non-explosive (effusive eruptions), or what caused the eruption (hydrothermal, phreatic, phreatomagmatic, etc.).
eruption
The hot, molten material is called - when it’s underground
magma
The hot, molten material is called - when it reaches the surface.
lava
are large dome-shaped volcanoes with broad gentle slopes and large craters.
Shield Volcanoes
volcano that are steeper and have smaller craters They are usually made up of loose pyroclastic material called scoria, a dark-colored igneous rock that is highly vesicular (has lots of vesicles or cavities) and made from extruded basaltic magma.
Cinder cones
volcano that’s symmetrical steep-sided cone-shaped morphology. Alternating layers of viscous andesitic lava flows, volcanic ash, and cinders are responsible for their shape.
composite volcano
is the primary source of precipitation and cloud formation in the atmosphere and, thus, a significant factor when predicting the weather.
Water Vapor
These are minuscule solid and liquid particles that are suspended in the air. - include smoke, pollen, sea salt, dust, airborne microorganisms, and other natural or man-made sources.
Aerosols
It is a form of oxygen with three oxygen atoms in each molecule (O3).
Ozone
Parts of the Atmosphere
Troposphere
Stratosphere
Mesosphere
Thermosphere
This is the lowest layer of the atmosphere. In this layer, temperature decreases with increasing altitude. The - is the most crucial layer for meteorologists because all weather phenomena occur here.
Troposphere
The temperature in this region increases with altitude because the ozone layer is located here.
Stratosphere
protects us from meteors by burning up most meteors and asteroids before they reach the Earth’s surface.
Mesosphere
Temperatures start to rise again in this layer due to oxygen and nitrogen atoms’ constant absorption of high-energy radiation from the Sun. It is in this layer where satellites orbit around the Earth.
Thermosphere
refers to the conditions of the atmosphere in a region over a short period of time.
Weather
is the long-term behavior of the atmosphere over a region.
climate
These are thin, wispy, and white clouds that resemble hair.
Cirrus clouds
These are thin layers of clouds that cover extensive portions of the sky.
Stratus clouds
