Ch 1: Foundation of the Earth Flashcards
What makes an idea scientific?
It can tested against observation or experiment
Earth Science is primarily an _______ science.
observational
What are Principles
Generalizations with exceptions. eg: Principle of Superposition, exception: overturned strata in mountain belts
What is the Principle of Uniformitarianism
James Hutton - Ancient features of the Earth are best interpreted in terms of processes that operate at the present day. aka Hutton’s unconformity
What is the Principle of Actualism
Ancient features of the Earth are to be interpreted in terms of physical and chemical processes that operate at the present day
What are Laws
applied to theories which are very well established and for which no exceptions are known. eg: Law of conservation of energy
Geophysicists
Magnetism, gravity, seismic waves
Geologists
Mapping, field observations, sampling, chemicla analyses
Paleontologists and Biogeographers
Paleontologist: fossils and history of life.
Biogeographers: distribution of living things at the present day.
Hydrologists and Oceanographers
Liquid water on the Earth’s surface, sediments deposited on the sea floor
Glaciologists
Behavior and distribution of ice. Materials deposited on the landscape by ice
Atmospheric Scientists
Meteorologists and climatologists: physics of the atmosphere. Short-term (weather) Long-term (climate)
What is a system?
A portion of the universe that can be separated from the rest for the purpose of observing changes>
What is an isolated system?
No matter or energy lost or gained.
What is a closed system?
No matter lost or gained, energy may be exchanged with surroundings. Earth is a closed system.
What is an open system?
Matter and energy exchanged with surroundings
What system is Earth?
An almost closed system. Amouts are negligible.
Systems within Earth
Atmosphere, Biosphere, Hydrosphere, Geosphere
What are Cycles
cycles trace the flow of material or energy through a system. Energy cycle, hydrologic cycle, rock cycle.
What is a budget?
When a cycle is quantified
The Energy Cycle/Budget
Drives all the processes that we see operating on the Earth.
Energy Pathways inputs
Energy inputs: solar radiations, geothermal energy, tidal energy
Energy Loss
Reflected into space, re-radiated
Solar Radiation
Energy comes from the sun as light, UV and other types of radiation. About 1.74 x 10^17 watts or 174000 tW
Where does Solar Energy go?
- 30% reflected into space (52000tW)
- < 50% converted to heat and re-radiated (81000tW)
- < 25%% melts ice and evaporates water into hydrosphere (40000tW)
- 350tW are converted to winds, currents, waves
- 40tW captured by living things
Geothermal Energy and where does it go?
Energy is released within the Earth by slow breakdown of radioactive elements. (about 32tW)
- Volcanoes and hot springs (0.3tW).
- Volcanoes under the sea (11tW)
- Heat loss/Conduction (21tW)
- Converted into movement: lava. geysers, plate tectonics.
Tidal Energy and where does it go?
Gravity of the moon raises a bulge in the ocean surface. (27tW)
- Ultimately converted to heat as water moves over the solid Earth.
Hydrologic Pathways: Evapotranspiration
Evaporations: from the surface water, land
Transpiration: from plants
Hydrologic Pathways: Condensation and precipitation
Condensation: clouds
Precipitation: rain, snow
Hydrologic Pathways: Surface and subsurface flow
Melting
Surface flow: glaciers, streams, rivers
Infiltration
Groundwater movement
Hydrologic Reservoirs
Oceans (97.5%)
Ice Sheets (1.85%)
Groundwater (0.64%)
Lakes, rivers, atmosphere (0.01%)
Residence Time
Size of reservoir / flow rate = residence time
A measure of how long the average water molecule spends in the reservoir.
Oceans/icecaps: 1000s of years
Streams and rivers: a few weeks
Atmosphere: a few days
The Rock cycle
Cycling of rock material at surface of the Earth.
What is Magma?
Molten rock that is underground: solidifies slow = bigger crystals
What is Lava?
Molten rock on the surface: solidifies fast = smaller crystals
How to tell where the magma solidified?
Crystal size
Temperature range of Magma/Lava
800C - 1200C
Felsit (silica rich, pale) - Mafic (iron and magnesium rich, dark)
Igneous Rock
cooling and solidification: granite and pillow lava
Weathering
reactions, creature interactions, not erosion. Happens in situ (in place) no movement. Chemical/physical reaction in the material.
Erosion
caused by exposure. requires transportation. The wearing away of land or soil by the action of wind, water or ice.
Sediment
Reduced pieces. May be deposited
Sedimentary Rock
Lithification
Lithification
the process in which sediments compact under pressure
Metamorphism
Heat and pressure, without melting
Metamorphic rocks
New minerals, change in texture, fabric
