Intro to Earth Systems and Earth Science GEOLOGICAL TIME SCALE AND EARTH’S STRUCTURE Textbook pages 207-209, 212

GEOLOGY The 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 https://www.youtube.com/watch?v=lMfPSdrrjZI

RELATIVE TIME MEASUREMENTS Measurements that give you the age of rock and soil layers by comparing them to layers above and below RELATIVE DATING PRINCIPLE OF SUPERPOSITION Strata are laid down in succession (layers are piled on top of each other over time) Dates an unknown sample to a certain time period when compared to samples of a known time period Top layers are youngest Bottom layers are oldest

ABSOLUTE DATING Process of determining an approximate age of rocks by using radiometric methods https://www.youtube.com/watch?v=phZeE7Att_s

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 DINOSAURS PALEOCENE EPOCH) 1.8 MILLION YEARS AGO(CENOZOIC ERA/QUATERNARY PERIOD) =FIRST MAN/MAMMALS/INSECTS/FLOWERS PLEISTOCENE EPOCH)

Geologic Time Scale Music Video https://www.youtube.com/watch?v=7PQURsc2SYs

Earth and our Solar System _________ planet from the Sun 3rd *only planet that can support _______________ life *orbits the Sun in an ____________ pattern/shape elliptical *takes ________ days to complete one orbit 365 *takes _____ hours to complete one rotation 24 *was formed _______ billion years ago 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) https://www.youtube.com/watch?v=BBwqendK8zc

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 EARTH CRUST = 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 EARTH 1. 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, dense solid nickel and iron due to pressure, over 4000 ° C

Comparison of the Compositional and Physical Layers

What is plate tectonics? If you look at a map of the world, you may notice that some of the continents could fit together like pieces of a puzzle.

The Earth’s crust is divided into 12 major plates which are moved in various directions. This plate motion causes them to collide, pull apart, or scrape against each other. Each type of interaction causes a characteristic set of Earth structures or “tectonic” features. The word, tectonic, refers to the deformation of the crust as a consequence of plate interaction.

World Plates This diagram shows the major Tectonic Plates. Presenter: Point out the UK, sitting on the Eurasian Plate. Also the plate boundary between Africa and South America (note that it has the same shape as the coastlines in these countries).

What are tectonic plates made of? Plates are made of rigid lithosphere. The lithosphere is made up of the crust and the upper part of the mantle. Plates are made of rigid lithosphere – formed of the crust and the extreme upper mantle (point out these layers on the figure).

What lies beneath the tectonic plates? Below the lithosphere (which makes up the tectonic plates) is the asthenosphere. The asthenosphere, beneath the lithosphere, is part of the upper mantle and is so hot that it is 1 – 5% liquid (I.e. 95 – 99% solid). This liquid, usually at the junctions of the crystals, allow it to flow – which is why ‘astheno’ means weak.’ Beneath the asthenosphere is the rest of the mantle, which is completely solid – but can also flow (on geological time scales) because of the intense temperatures and pressures involved. The base of the lithosphere-asthenosphere boundary corresponds approximately to the depth of the melting temperature in the mantle. The plastic layer below the lithosphere The plates of the lithosphere float on the asthenosphere

Plate Movement “Plates” of lithosphere are moved around by the underlying hot mantle convection cells How and Why do tectonic Plates move around? The question of how tectonic plates are moved around the globe is answered by understanding mantle convection cells. In the mantle hot material rises towards the lithosphere (like hot air rising out of an open oven - ever opened an oven door and felt the blast of hot air coming past your face?). The hot material reaches the base of the lithosphere where it cools and sinks back down through the mantle. The cool material is replaced by more hot material, and so on forming a large “convection cell” (as pictured in the diagram). This slow but incessant movement in the mantle causes the rigid tectonic plates to move (float) around the earth surface (at an equally slow rate).

Plate Tectonics Excel Graph Activity On our class webpage is the link for the activity (word document) and the data (excel document) See Plate Tectonics Exercise 1. Work on the webquest when you are done