introduction to geology (1) Flashcards
Geology
The science that examines Earth, its form and composition and the changes that it has undergone and is undergoing
Physical Geology
A major division of geology that examines the materials of Earth and seeks to understand the processes and forces acting beneath and upon Earth’s surface
Historical Geology
A major division of geology that deals with the origin of Earth and its development through time. Usually involves the study of fossils and their sequence in rock beds.
List three different geological hazards.
Earthquakes
Volcanoes
Landslides
Aside from geologic hazards, describe another important connection between people and geology.
Geologic resources, we use a lot of resources
People influence geologic processes
Describe Aristotle’s influence on geology.
Aristotle presented nebulous ideas, but he was authoritative and his ideas were prominent until the renaissance
Catastrophism
The concept that Earth was shaped by catastrophic events of a short-term nature
(James Ussher)
Uniformitarianism
The concept that the processes that have shaped Earth in the geologic past are essentially the same as those operating today
Who published Theory of the Earth?
James Hutton
What is the age of the Earth?
4.6 billion years
Which eon, era, period and epoch do we live in?
Phanerozoic
Cenozoic
Quaternary
Holocene
Hypothesis
A tentative explanation that is then tested to determine if it is valid
Theory
A well-tested and widely accepted view that explains certain observable facts
Scientific Method
The process by which researchers raise questions, gather data, and formulate and test scientific hypothesis
Hydrosphere
Water portion of the planet
Atmosphere
Earth’s gaseous envelope
Geosphere
Solid earth
Biosphere
Totality of all plant and animal life on Earth
Soil
the thin veneer of material at Earth’s surface that supports the growth of plants, may be thought of as part of all four spheres
Earth System Science
An interdisciplinary study that seeks to examine Earth as a system composed of numerous interacting parts or subsystems
System
A group of interacting or interdependent parts that form a complex whole
How much of Earth’s surface do oceans cover?
71%
What percentage of Earth’s water supply do oceans represent?
96%
List 3 examples of systems.
Car
Economy
Planet
What are the two sources of energy for the Earth system?
Energy released from radioactive decay
Sun
When is it thought that the Big Bang occurred?
13.7 billion years ago
Nebular Theory
A model for the origin of the solar system that supposes a rotating nebula of dust and gases that contracted to form the Sun and planets
Solar Nebula
The cloud of interstellar gas and/or dust from which the bodies of our solar system formed
Describe the steps in the formation of Earth’s layered structure
Heavy elements (iron) sunk and less massive elements rose (oxygen)
List the inner planets
Mercury, Venus, Earth, Mars
List the outer planets
Jupiter, Saturn, Uranus, Neptune
What are the differences of the inner and outer planets?
Inner, rocky planets are small and dense
Outer, gas planets are large and gaseous
Explain why density and buoyancy were important in the development of Earth’s layered structure.
Density allowed layers to sink or rise
Crust
The very thin, outermost layer of Earth
Mantle
The solid rocky shell that extends from the base of the crust to a depth of 2900 kilometers
What percent of Earth’s volume is the mantle?
82%
Lithosphere
The rigid outer layer of Earth, including the crust and upper mantle
Asthenosphere
A subdivision of the mantle situated below the lithosphere. This zone of weak material exists below a depth of about 100 km and in some regions extends as deep as 700 km. The rock within this zone is easily deformed.
Transition Zone
The lowest portion of the upper mantle
Lower Mantle
The part of the mantle that extends from the core-mantle boundary to a depth of 660 km
D” Layer
The boundary layer between the rocky mantle and the hot liquid iron outer core will be examined in
Core
The innermost layer of Earth. It is thought to be largely an iron-nickel alloy, with minor amounts of oxygen, silicon, and sulfur
Outer Core
A layer beneath the mantle about 2270 km thick, which has the properties of a liquid
Inner Core
The solid innermost layer of Earth, about 1216 kilometers in radius
What generates Earth’s magnetic field?
The movement of metallic iron within the outer core
Why is the inner core solid?
The immense pressures that exist in the center of the planet (despite the higher temperature)
Minerals
Chemical compounds (or sometimes single elements) that each have their own composition and physical properties
Rock Cycle
A model that illustrates the origin of the three basic types and the interrelatedness of Earth materials and processes
Igneous Rock
Rock formed from the crystallization of magma
Sediment
Unconsolidated particles created by the weathering and erosion of rock by chemical precipitation from solution in water, or from the secretions of organisms, and transported by water, wind, or glaciers
Sedimentary Rock
Rock formed from the weathered products of preexisting rocks that have been transported, deposited, and lithified
Metamorphic Rock
Rock formed by the alteration of preexisting rock deep within Earth (but still in the solid state) by heat, pressure, and/or chemically active fluids
List two rock characteristics that are used to determine the processes that created a rock.
Composition and texture
What are the two principal divisions of Earth’s surface?
Ocean basins and continents
Ocean Basin
A deep submarine region that lies beyond the continental margins
Continents
A large, continuous area of land that includes the adjacent continental shelf and islands that are structurally connected to the mainland
The _____ _____ that comprise the oceanic crust average only _ km thick and have an average density of about ___ g/cm3.
basaltic rocks
7
3.0
The continents average about __ km thick and are composed of ____ ____ that have a density of about ___ g/cm3.
35
granitic rocks
2.7
Continental Margin
The portion of the seafloor that is adjacent to the continents. It may include the continental shelf, continental slope, and the continental rise
Continental Shelf
The gently sloping submerged portion of the continental margin, extending from the shoreline to the continental slope
Continental Slope
The steep gradient that leads to the deep-ocean floor and marks the seaward edge of the continental shelf
Continental Rise
The gently sloping surface at the base of the continental slope
Deep-Ocean Basins
The portion of seafloor that lies between the continental margin and the oceanic ridge system. This region comprises almost 30% of Earth’s surface
Abyssal Plain
A very level area of the deep-ocean floor, usually lying at the foot of the continental rise
Deep-Ocean Trench
A narrow, elongated depression of the seafloor
Seamount
An isolated volcanic peak that rises at least 1000 meters above the deep-ocean floor
Mid-Ocean Ridge
A continuous mountainous ridge on the floor of all the major ocean basins and varying in width from 500 to 5000 km. The rift at the crests of these ridges represent divergent plate boundaries.
Mountain Belt
A geographic area of roughly parallel and geologically connected mountain ranges developed as a result of plate tectonics
Craton
The part of the continental crust that has attained stability; that is, it has not been affected by significant tectonic activity during the Phanerozoic eon. It consists of the shield and the stable platform
