Chapter 2: Earth Systems
Chapter 2: Earth Systems GEOL 1005
Popular in Environmental Geology
Popular in Geology
This 6 page Class Notes was uploaded by Kerrigan Unter on Monday October 19, 2015. The Class Notes belongs to GEOL 1005 at George Washington University taught by Brown, C in Summer 2015. Since its upload, it has received 30 views. For similar materials see Environmental Geology in Geology at George Washington University.
Reviews for Chapter 2: Earth Systems
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/19/15
GEOL 1005 Chapter 2 Earth Systems 2 Earth s Geosphere Geosphere solid Earth together with the molten parts that lie deep within it Nebula immense cloud of gas and interstellar debris Solar system dust rocks and gases swirling around the Sun that coalesced to from planets Core contains two parts the solid inner core and the liquid outer core Inner core accounts for 17 of Earth s mass composed of iron and nickel solid in spite of extreme high temperatures because of very high pressures at Earth s center Outer core 308 of Earth s mass liquid because pressure is slightly lower temperatures still very high Mantle 671 of Earth s mass composed of mostly magnesium silicon oxygen and iron Lower mantle solid rock that gradually increases in density and seismic wave velocity downward toward the boundary with the molten material of the outer core Mantle transition zone well defined by changes in seismic wave velocities at its boundaries Upper mantle lies above the transition zone and extends upward to the base of the crust Asthenosphere distinctive part of the upper mantle directly below the lithosphere mostly solid but pliable and can ow under pressure upper mantle s low velocity zone Lithosphere shallowest physical layer in the geosphere it is made up of strong rigid rocks that can break when they move Crust outer thin layer 70 km at its deepest point Continental crust Earth s landmasses and their shallowlysubmerged edges Granite rock containing calcium sodium potassium aluminum silicon and oxygen Oceanic crust second type of crust that underlies the oceans thin ironrich and young compared to the continental crust Basalt formed from partially melted mantle that migrates to Earth s surface at sea oor volcanoes oceanic crust consists primarily of this Density mass per unit volume Minerals naturally occurring solids With an orderly arrangement of atoms and distinct chemical composition 22 Earth s Atmosphere Atmosphere gases that surround the Earth Nebular cloud gases condense to form the solar system contains hydrogen helium methane and ammonia First atmosphere early atmosphere of Earth formed from the nebular cloud very high in temperature Volatiles elements and compounds that vaporize easily hydrogen carbon nitrogen water carbon dioxide and ammonia Carbonaceous chondrites primitive meteorites containing volatiles Volcanoes are a key way that matter is transferred from Within the geosphere to Earth s surface and the atmosphere Magma molten rock Within the geosphere Lava molten rock on the surface Outgassing volcanic processes that transfer volatile components from the geosphere to the atmosphere Second atmosphere created through outgassing early in our planet s history Greenhouse gases carbon dioxide methane and water vapor Third atmosphere current atmosphere A lot of water and carbon dioxide had to be removed and a lot of nitrogen and oxygen had to be added to create the third atmosphere Calcium carbonate dissolved carbon dioxide reacted With calcium accumulated along the sea oor Nitrogen is the most abundant element in Earth s third atmosphere Photosynthesis sunlight is used to convert carbon dioxide and water into food and oxygen Cyanbacteria earliest forms of microorganisms on Earth photosynthetic Banded iron formations formed through chemical reactions solid layers of mainly iron oxides that accumulated through sediments that became rocks sinks were Earth s early oxygen is stored today Because the atmosphere s gases are compressible gravity pulls most of the gases down to low levels near Earth s surface 90 of the atmosphere s mass is below 16 km Homosphere compositionally homogenous part of the atmosphere containing the same proportions of nitrogen oxygen and argon throughout Heterosphere above the homosphere contains few gas molecules heterogeneous compositional character molecules with greater masses nitrogen are concentrated lower and molecules with lower masses oxygen helium hydrogen are concentrated higher Troposphere lowest layer temperatures decrease from Earth s surface upward to the top of the troposphere area where temperature become constant called tropopause 717 km in height depending on location on Earth Stratosphere layer above the troposphere up towards 50 km in height temperatures in crease upward through the stratosphere top of stratosphere is marked by a temperature decrease called stratopause temperature changes through the stratosphere are caused by the interaction of incoming solar radiation which creates ozone ozone layer contained in lower part of stratosphere ozone is a good absorber of ultraviolet radiation Mesosphere Layer above stratosphere 5085 km in altitude Temperature decrease upwards through the mesosphere to a zone where the lowest temperatures in the atmosphere are present called the mesopause Low concentration of gas molecules that absorb ultraviolet radiation very small amounts of carbon dioxide Thermosphere Layer above the mesosphere Temperatures increase and air molecules become fewer and fewer upward through the thermosphere 480 km Also called ionosphere When solar radiation is intense gas molecules can become ions Ion charged particles Exosphere where the atmosphere merges with space 23 Earth s Hydrosphere Covers 71 of the Earth s surface Volcanic outgassing released volatile elements and compounds including water vapor during the formation of the Earth s second atmosphere Once the planet cooled the water vapor condensed 972 of Earth s water is in the ocean 28 is fresh water Ice makes up 686 of Earth s freshwater Freshwater is widely distributed in lakes streams rivers underground and in the atmosphere Specific heat capacity amount of heat energy required to raise the temperature of one gram of water by one degree centigrade Glacier large mass of ice moving slowly Ice cap glaciers less than 50000 km2 Ice sheet glaciers more than 50000 km2 Ice covers 10 of Earth s land area Antarctic ice is the largest accumulation of freshwater ice on Earth Water cycle transfers water among its reservoirs in the oceans the atmosphere on land and below the land s surface Precipitation transfers water to three hydrosphere reservoirs on land Ice accumulates in glaciers ice caps and ice sheets Surface water in streams rivers ad lakes Groundwater below the land surface 24 Earth s Biosphere Consists of all life on Earth Fossils remains and indications of former life that are preserved in rocks Stromatolites fossils found in even older rocks approximately 35 billion years old Evolution change in organisms over successive generations that leads to new forms and functions and new species Natural selection process in nature by which organisms better adapted to their environment tend to survive outreproduce less welladapted members of their population and transmit their genetic characteristics in increasing numbers to succeeding generations The Origin of Species by Charles Darwin Variation in traits Differential reproduction Descent of traits through hereditary Mass extinctions large number of species become extinct At least 5 major mass extinctions in the last 540 million years Currently extinction rates are as high as 70700 species per year compared to the long term average of 110 species per year 25 Understanding Geologic Time and Earth History Geologic time periods of time longs enough to give us perspective and understanding of Earth s history Relative age identifies whether one material or event is older or younger than another Sediment material carried along by currents and deposited on river lake or ocean bottom accumulate in layers and eventually become sedimentary rocks Fossil successions sequence of fossil types in a distinctive order that represents changes in the biosphere through geologic time Geologic time scale chronologic arrangement of the periods and events in geologic time Eon major interval of geologic time on the geologic time scale Hadean eon 45385 billion years ago surface cooled Archean eon 38525 billion years ago simplest forms of life evolved continents formed Proterozoic eon 25054 billion years ago continental masses approach present sizes seas formed life gained complexity Phanerozoic eon 542 million years ago to present diversity of life Isotopes atoms of an element that have different atomic masses Halflife the time it takes for half of an isotope s atoms to decay Radiometric dating determination of a natural material s age by measuring the concentrations of radioactive elements and their decay products included Within the material Absolute ages numerical age of any physical entity or even in years before the present
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'