GEOLOGY geo = earth logos = discourse study/science of the Earth materials, processes, products history of the planet and its life forms since its origin study of the Earth and all other solid bodies in space (astrology) its beginning is lost in antiquity modern geology was born in the 1788 1968 Unifying theory of Earth sciences (44 years old) Earth: 4.5 4.6 Billion years old

Major Branches1. Historical- history of the Earth and its life forms- stratigraphy- strata/strarum : layers/beds of rocks- relationship, composition, fossil of rocks- paleontology- paleo=ancient- history of life forms, ancient organisms- micropaleontology- the ff. are protists (one-celled):- foraminifers- skeleton: calcareous (CaCO3 or calcium carbonate)- HCl- radiolarians- skeleton: siliceous (SiO2)- HF- geochronology- study of sequence/timing of events2. Physical- materials, processes and products- crystals: Crystallography- mineral: Mineralogy- rocks: Petrology- volcanoes: Volcanology- land forms: Geomorphology- structures: Structural Geology- weather: Meteorology- earthquake: Seismology

- Eclectic science- ideas from other fields of science- geology + physics = geophysics- geology+ chemistry = geochemistry- geology + biolody = paleontology- powerful tool: geologic mapping- color represents specific rocks with the same history- topographic map: contour lines = equal elevation- has demonstrated the immensity of time- provided the background for organic evolution- Charles Darwins theory of evolution- boring and fascinating science (field-oriented)

Applications of Geology1. Mitigation of natural disasters- NDRMMC: gov. agency2. Environmental impact assessment- Foundation stability analysis3. Preservation of natural resources4. Utilization of water, energy, and other natural resources5. Unraveling the history of life and of the Earth

Uniformitarianism- the physical, chemical and biological features of the Earth were produced by the same processes that are acting today- the physical, chemical, and biological laws that operate today have also operated in the geologic past- James Hutton- Uniformity of Causes- Father of Modern Geology- Edinburgh physician, geologist, farmer, gentleman- 1788, Theory of the Earth, Transaction of the Royal Society of Edinburgh- he said that the history of the planet is composed of long and numerous cycles (geocycles)- no beginning, no end- proof: Siccar Point, Berwick shire, British Geological Survey- flat-lying beds, tilted beds- middle: unconformity or surface of erosion or non-deposition- outcrop: exposure- sand, sandstone, sand- The present is the key to the past.- uniformity of processes but not of rate, time, and place of occurrence- the earth changes but only in accordance with unchanging physical laws

Catastrophism- earths history as a series of catastrophes- each exterminated the existing life- Baron Georges Cuvier- 6 catastrophism- Paris Basin- outcrop with 6 catastrophes, separated by unconformities- 5 catastrophes, no one survived - Great Deluge (Noahs Ark): 6th deluge- NOT TRUE- other places: each layer with mixed species

EARTH

Big Bang- this occurrence was not a conventional explosion but rather an event

Nebular Hypothesis- nebula: cloud of dust and gasa. started to gravitationally collapseb. contracted to a rotating disc heated by the conversion of gravitational energy to thermal energyc. cooling resulted into the rocky and metallic material to condense into tiny solid particlesd. repeated collisions from dust-sized particles to asteroid-sized bodiese. accretion into planetsf. differentiate to create layers- globules: small, dark, round nebulae- gas to liquid to solid

3 layers:1. Core2. Mantle3. Crust

Erastosthenes- Greek mathematician, geographer, astronomer- used geodesy- applied math- measurement of the Earth and other large areas- (distance between 2 points/angelOBSERVATIONS:1. Shadows at noon are shorter, shadows get shorter as the time approaches noon, closer to the equator2. A part of every well is in shadow during the summer solstice in Alexandria, Egypt3. However, there is no shadow in Syene at noon.4. Alexandria is 925 km due North of Syene

ASSUMPTIONS:1. The sun is so distant that its rays are virtually parallel.2. A plabe passing through Syene and Alexandria at noon would also pass through the center of the Earth 3. Plumb lines point directly to the center of the Earth- plumb bob (for leveling)4. The east and west walls of the well in Alexandria are North-South planes.5. The Earth is a sphere.

Polar circumference= (distance from Syene to Alexandria)360/(angle of suns ray to the vertical Alexandria)= between 45,000 and 47,000 kms- 14% bigger than actual: 40,008 kms

ERROR:1. Syene is not in the North of Alexandria2. Syene is not in the Tropic of Cancer

Earth- oblate spheroid- a degree latitude is bigger in Finland than in Peri

1976: International Union of Geogesy and Geophysics

Polar diameter12,713.54 kms

Equatorial diameter12,756.32 kms

Polar circumference40,008.00 kms

Equatorial circumference40,075.16 kms

ATMOSPHERE:- gaseous envelope of the Earth- 78% Nitrogen, 21% oxygen- original atmosphere was different- Nebular hypothesis- blown away by solar winds- methane, ammonia, Hydrogen- second atmosphere- frozen gases were trapped- no oxygen before- water vapor - photochemical dissocation- chemical action of light- H, O2- early photosynthesis- cyanobacteria, blue green algae

HYDROSPHERE:- constant motion- Global Ocean- most prominent feature of the hydrosphere, 70.8% of the Earth- Glacier- glacial ice- land: 29.2%

BIOSPHERE:- narrow zone extending from the photic zone to the snowline in tropical and subtropical mountain ranges- photic zone: sunlit surfaces 200-300 m below surface- snowline: 6000 m above sea level- main factors: temperature, pressure, chemistry

LITOSPHERE- biggest- Continents- triangular- N hemisphere- flata. Basement complex or shield- deformed rocks eroded down to sea level- Canadian Shieldb. Stable platform- basement complex is covered with veneer of sedimentary rocks- platform in Nashville, Tennesseec. Folded mountain belts- applachian mountains- less dense rocks-