Exam One 2
Terms
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- What is a hypothesis?
- A tentative explanation that is then tested to determine if it is valid.
- What is Uniformitarianism?
- The concept that the processes that have shaped Earth in the geologic past are essentially the same as those operating today.
- What is a rock?
- A consolidated mixture of minerals.
- Relative Dating
- Rocks and structures are placed in their proper sequence or order. Only the chronological order of events is determined.
- Law of superposition
- In any undeformed sequence of sedimentary rocks, each bed is older than the one above and younger than the one below.
- Theory
- A well tested and widely accepted view that explains certain observable facts.
- Ion
- An atom or molecule that possesses an electrical charge.
- Mineral
- A naturally occurring, inorganic crystalline material with a unique chemical structure.
- Paleozoic era
- A time span on the geologic time scale between the Precambrian and Mesozoic eras--from about 540 million to 248 million years ago.
- Dike
- A tabular-shaped intrusive igneous feature that cuts through the surrounding rock.
- Batholith
- A large mass of igneous rock that formed when magma was amplaced at depth, crystallized, and was subsequently exposed by erosion.
- Magma
- A body of molten rock found at depth, including and dissolved gases and crystals.
- Viscosity
- A measure of a fluid's resistance to flow
- Bowen's reaction series
- A concept proposed by N.L. Bowen that illistrates the relationships between magma and the minerals crystallizing from it during the formation of igneous rocks.
- Weathering
- The disintergration and decomposition of rock at or near the surface of the earth.
- Wilson Cycle (Supercontinent Cycle)
- The idea that the rifting and dispersal of one supercontinent is followed by a long period during which the fragments gradually reassemble into a new supercontinent.
- Transform Fault
- A major strike-slip fault that cuts through the lithosphere and accommodates motion between two plates
- Transform Fault Boundary
- A boundary in which two plates slide past one another without creating or destroying lithosphere.
- Unicomformity
- A urface that represents a break in the rock record, caused by erosion and nondeposition
- Compressional Stress
- Differential stress that shortens a rock body
- Shield Volcano
- A broad, gently sloping volcano built from fluid basaltic lavas.
- lithosphere
- the rigid outer layer of earth, including the crust and upper mantle
- mesosphere
- the part of the mantle that extends from the core-mantle boundary to a dpeth of 660 kilometers. Also known as the lower mantle.
- Convergent plate boundary
- a boundary in which two plates move together, resulting in oceanic lithosphere being thrust beneath an overriding plate, eventually to be reabsorbed into the mantle. It can also involve the collision on two continental plates to create a mountain system.
- Divergent plate boundary
- a boundary in which two plates move apart, resulting in an upwelling of material from the mantle to create new seafloor.
- Original Horizontality
- layers of sediment that are generally deposited in a horizontal or nearly horizontal position.
- Cross-Cutting
- a principle of relative dating. A rock or fault is younger than any rock or fault through which it cuts.
- Inclusion
- A piece of one rock unit contained within another. Inclusions are used in relative dating. The rock mass adjacent to the one containing the inclusion must have been there first in order to provide the fragment.
- Resources
- water and soil, a variety of mettalic and nonmetallic minerals, and energy
- Earth is gaining ____ people per year
- 100 million
- the magnitude and frequency of flooding can be changed significantly by human activities such as:
- clearing forests, building cities, and constructing damns.
- Who was the most influential greek philosopher?
- Aristotle
- Problems and issues addressed by geology include
- Natural hazards, resources, world population growth, and environmental issues
- Catastrophism
- the belief that earth's ladscapes had been shaped primarily by great catastrophes.
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Science assumes the natural world is
__________ and ___________ - consistent and predictable
- Scientific method involves
- Gathering facts through observations and the formulation of hypotheses and theories
- EarthÂ’s four spheres
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Hydrosphere
Atmosphere
Biosphere
Solid Earth - system
-
Any size group of interacting parts that form a complex whole
Open vs. closed systems - Negative feedback
- maintains the status quo
- Positive feedback
- enhances or drives changes
- The Earth system is powered by the Sun that drives external processes in the
-
Atmosphere
Hydrosphere
At EarthÂ’s surface - The Earth system is also powered by
- Earth's interior
- Nebular hypothesis
- proposes that the bodies of our solar system evolved from an enormous rotating cloud called the solar nebula.
- solar nebula is composed of
- hydrogen and helium
- Nebula began to contract about
- 5 billion years ago
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Formation of EarthÂ’s layered structure:
_____ sank to the center
_________ rose to produce a primitive crust
________________ established the three basic divisions of EarthÂ’s interior
Primitive atmosphere evolved from _____ in Eart -
Metals
Molten rock
Chemical segregation
gases - Layers defined by composition
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Crust
Mantle
Core - Layers defined by physical properties
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Lithosphere
Asthenosphere
Mesosphere
Inner and Outer Core - EarthÂ’s surface
-
Continents
Oceans - Continents
-
Mountain belts
The stable interior - Mountain belts
- Most prominent feature of continents
- The stable interior
- Also called a craton – composed of shields and stable platforms
- Continental margins
- Includes the continental shelf, continental slope, and the continental rise
- Deep-ocean basins
-
Abyssal plains
Oceanic trenches
Seamounts - Ocean Basins
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Continental margins
Deep-ocean basins
Oceanic ridge system - Oceanic ridge system
-
Most prominent topographic feature on Earth
Composed of igneous rock that has been fractured and uplifted - Basic rock types
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Igneous rocks
Sedimentary rocks
Metamorphic rocks - Igneous rocks
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Cooling and solidification of magma (molten rock)
Examples include granite and basalt - Sedimentary rocks
-
Accumulate in layers at EarthÂ’s surface
Sediments are derived from weathering of preexisting rocks
Examples include sandstone and limestone - Metamorphic rocks
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Formed by “changing” preexisting igneous, sedimentary or other metamorphic rocks
Driving forces are increased heat and pressure
Examples include gneiss and marble - The Rock Cycle: One of EarthÂ’s subsystems
-
The loop that involves the processes by which one rock changes to another
Illustrates the various processes and paths as earth materials change both on the surface and inside the Earth - theory of plate tectonics
- provided geologists with the first comprehensive model of Earth's internal workings.
- Hydrosphere
- a dynamic mass of water that is continually on the move, evaporating from the oceans to the atmosphere, precipitating to the land, and running back to the ocean again.
- Atmosphere
- A life-giving gaseous envelope. Thin and tenuous.
- Biosphere
- Includes all life on Earth
- Solid Earth
- Lies beneath the atmosphere and the ocean
- Earth Science System
- to understand our planet scientists learn how land water air and life are interconnected
- open systems
- most natural systems--both energy and matter flow into and out of the system
- closed system
- energy moves freely in and out of the system but matter never enters or leaves it.
- Crust
- Thin, rocky outer skin is generally divided into oceanic and continental crust. Oceanic is composed of dark igneous rock basalt. Continental consists if many rock types.
- The rocks of the ____ crust are younger and more dense than ______ rocks
- oceanic, continental
- Mantle
- a solid, rocky shell that extends to a depth of 2900 kilometers
- Core
- composition of the core is thought to be an iron-nickel alloy with minor amounts of oxygen, silicon, and sulfur--elements that readily form compounds with iron.
- Inner core
- a sphere having a radius of 1216 kilometers. Despite its higher temperature, the material in the inner core is stronger thant the outer core and behaves like a solid.
- outer core
- a liquid layer 2270 kilometers thick. It is the convective flow of metallic iron within this zone that generates earth's magnetic feild.