1. Intro to Earth Systems and Earth Science
GEOLOGICAL TIME SCALE
AND
EARTH’S STRUCTURE
Textbook pages , 212

2. GEOLOGY
The study of the nonliving parts of the Earth such as rocks, soil, and land features
GEOLOGIST study Geology

3. 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

4. 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

5. ABSOLUTE DATING
Process of determining an approximate age of rocks by using radiometric methods

6. 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

7. 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)

8. Geologic Time Scale Music Video

9. 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

10. 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

11. 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)

12. 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

13. 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

14. 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 ° C

15. Comparison of the Compositional and Physical Layers

16. 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.

17. 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.

18. 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).

19. 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).

20. 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

21. 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).

22. 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