APES UNIT 1 NOTES

GEOLOGICAL TIME SCALE AND

EARTH’S STRUCTURE

GEOLOGY

The study of the nonliving parts of the Earth such as:rocks, soil, 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 DATING

Dates an unknown sample to a certain time period when compared to samples of known ages

PRINCIPLE OF SUPERPOSITION layers are piled on top of each other over time…Strata are laid down in succession

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

EON

ERA

PERIOD

EPOCH

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)

• 2 MILLION YEARS AGO(CENOZOIC ERA/QUATERNARY PERIOD) =FIRST MAN/MAMMALS/INSECTS/FLOWERS

• PLEISTOCENE 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

GEOSPHERE = 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

GEOSPHERE

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, outermost layer, solid , brittle,

coolest layer, mostly oxygen

MANTLE = medium density, has magma that circulates, mostly iron, magnesium, aluminum

CORE = innermost layer, greatest density, hottest,mostly iron and nickel

LAYERS GET DENSER TOWARDS THE MIDDLE

PHYSICAL LAYERS OF EARTH

PHYSICAL1. 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