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Intro to Earth Systems and Earth Science
GEOLOGICAL TIME SCALE AND
EARTH’S STRUCTURE
Textbook pages 207-209, 212
GEOLOGYThe study of the nonliving parts of the Earth such as rocks, soil, and land features
GEOLOGIST study Geology
JAMES HUTTON
“FATHER OF MODERN GEOLOGY”
Figured out sedimentary rock gets compacted and compressed over time
PRINCIPLE OF UNIFORMITARIANISM=changes in the Earth’s surface happened slowly. Example: gradual shifting across different continental land forms
RELATIVE TIME MEASUREMENTSMeasurements that give you the age of rock and soil layers by comparing them to layers above and below
RELATIVE DATINGDates an unknown sample to a certain time period when compared to samples of a known time period
PRINCIPLE OF SUPERPOSITION Strata are laid down in succession(layers are piled on top of each other over time)
Top layers are youngestBottom layers are oldest
ABSOLUTE DATING
Process of determining an approximate age of rocks by using radiometric methods
GEOLOGICAL TIME SCALE
*The history of the Earth is measured in Geological Time*It is organized according to major events*The largest unit of time is EON
EONERA
PERIODEPOCH
IMPORTANT STAGES IN EARTH’S HISTORY*4.6 BILLION YEARS AGO (HADEAN EON) = ORIGIN OF EARTH- NO LIFE
*3.5 BILLION YEARS AGO (ARCHEON EON/PRECAMBRIAN ERA) = FIRST PROKARYOTIC CELL- LIFE*2.5 BILLION YEARS AGO(PROTEROZOIC EON/PRECAMBRIAN ERA) = ATMOSPHERIC OXYGEN EXISTS*1.5 BILLION YEARS AGO(PROTEROZOIC EON/PRECAMBRIAN ERA) = FIRST EUKARYOTIC CELL*550 MILLION YEARS AGO(PROTEROZOIC EON/
PALEOZOIC ERA/CAMBRIAN PERIOD) = PRIMITIVE ALGAE/MARINE INVERTEBRATES
*450 MILLION YEARS AGO (PHANEROZOIC EON/PALEOZOIC ERA/ = FIRST MARINE VERTEBRATES (FISH)ORDOVICIAN PERIOD)
*400 MILLION YEARS AGO (PHANEROZOIC EON/
PALEOZOIC ERA/SILURIAN PERIOD) = FIRST LAND INVERTEBRATES & PLANTS*200 MILLION YEARS AGO (MESOZOIC ERA/TRIASSIC PERIOD) = FRIST BIRDS/ROCKY MOUNTAINS FORM
*150 MILLION YEARS AGO (MESOZOIC ERA/JURASSIC PERIOD) = AGE OF DINOSAURS
*65 MILLION YEARS AGO(CENOZOIC ERA/TERTIARY PALEOGENE PERIOD)=EXTINCTION OF DINOSAURSPALEOCENE EPOCH)
1.8 MILLION YEARS AGO(CENOZOIC ERA/QUATERNARY PERIOD) =FIRST MAN/MAMMALS/INSECTS/FLOWERSPLEISTOCENE EPOCH)
Earth and our Solar System
• _________ planet from the Sun
*only planet that can support _______________
*orbits the Sun in an ____________ pattern/shape
*takes ________ days to complete one orbit
*takes _____ hours to complete one rotation
*was formed _______ billion years ago
3rd
life
elliptical
365
24
4.6
EARTH’S INTERACTIVE COMPONENTS
LITHOSPHERE = makes up the Earth’s interior (rock)
ATMOSPHERE = makes up the gases surrounding Earth (air)
HYDROSPHERE= makes up the areas of water
BIOSPHERE = makes up all the living things within the other
parts EARTH IS AN INTEGRATED SYSTEM OF 4 INTERACTING COMPONENTS
HOW EARTH FORMED- CAME FROM COSMIC DUST IN THE SOLAR SYSTEM (BIG BANG THEORY)- ALL THE ELEMENTS FOUND ON EARTH ARE AS OLD AS EARTH- EARLY EARTH WAS A HOT, MOLTEN SPHERE- AS MOLTEN MATERIAL COOLED, THE ELEMENTS SEPARATED INTO LAYERS
BASED ON MASS (HEAVY IRON TOWARDS THE CENTER)
EARTH LAYERS BECAUSE EARTH’S ELEMENTS SETTLED INTO PLACE BASED ON MASS…… EARTH IS DIVIDED INTO LAYERS
2 GROUPS OF LAYERS:
COMPOSITIONAL LAYERS&
PHYSICAL LAYERS
KNOWLEDGE OF EARTH’S LAYERS *SEISMIC WAVES ANALYSIS *LAVA ANALYSIS *METERITE COMPOSITION
COMPOSITIONAL LAYERS OF EARTHCRUST = thinnest (only 0.5% of earth’s total mass), outermost layer, solid, brittle, coolest layer, mostly oxygen, oceanic & continental
MANTLE = medium density, has magma that circulates in convection cells,mostly iron, magnesium, aluminum
CORE = innermost layer, greatest density, hottest,mostly iron and nickel
PHYSICAL LAYERS OF EARTH1. LITHOSPHERE = outer layer, includes crust
and uppermost mantle, divided into tectonic plates
2. ASTHENOSPHERE = middle part of mantle, flexible, rock flows slowly
3. MESOPHERE = lower part of mantle
4. OUTER CORE = outer part of core, dense liquid nickel and iron
5. INNER CORE = inner most part of core, densesolid nickel and iron due to
pressure, over 4000 ° C
Comparison of the Compositional and Physical Layers
Physical Layers