Beginnings

1. Earth’s formation2. Earth’s timeline

The Universe - formed 10-15 billion years ago Currently referred to as the ‘Big Bang‘

• current theory is that the universe was formed from something smaller than an atom

• the atom exploded and everything was blown outward with great heat and speed

Earth’s Formation

Our Solar System was formed 4.6 billion years agoThe Earth is assumed to be the same age http://www.talkorigins.org/faqs/faq-age-of-earth.html

• At this time, Earth had a surface~ known from radiometric dating of meteorites (uranium and potassium)

• We think water condensed on the planet 3.9 billion years ago~ known from radiometric dating of sedimentary rocks that

formed by processes requiring water

Earth’s Formation

Old Theory:

a) H2O came from big comets during period of heavy bombardment

a) H2O locked up in minerals released from differentiation (cooling and melting of magma) and

heating processes

Earth’s FormationWhere did oceans come from?

New Theory:

a) Oceans are still forming and H2O comes from many small cometessimals that continually bombard the Earth

a) H2O came from big comets during period of heavy bombardment

a) H2O locked up in minerals released from differentiation and heating

Where did oceans come from? (cont’d)

Earth’s Formation

Mother Earth formed 4.6 billion years ago..

What has happened during this time?

Earth’s Timeline

Divide by 4.6 billion by 100 million years - makes Earth 46 years old

0-3 yrs no record3 yrs dated from rocks in Canada, Africa

and Greenland8-11 yrs 1st living cells - primitive bacteria22-23 yrs oxygen production by cells begins31 yrs atmosphere has enough oxygen to

support life39th yr first invertebrates-hard shelled fossils41rst yr primitive fish and corals

Earth’s Timeline (cont’d)

41-42 yrs land plants, fish43 yr reptiles, dinosaurs, sharks44 yr dinosaurs dominate45 yr dinosaurs die

1 yr ago plants and flowers proliferate7 mos. ago insects, mammals, birds proliferate25 days ago first humans6 days ago homosapiens1/2 hour ago 1st recorded civilization1 minute ago industrial revolution

change Earth and relationship with Earth for all time…

Earth’s Timeline (cont’d)

Earth

1. Coordinates2. Earth’s Water3. Earth’s Structure

Earth • Highest mountain is Mt. Everest at 8840m above sea level• Lowest trench is the Mariana Trench (Pacific) at 11,000m

below sea level

Earth has a huge mass!!!

Think of earth like a basketball - the bumps would be the mountains and the dimples would be the trenches.

Coordinates

Latitude and Longitude

Latitude• Parallel to the equator

• Expressed as degrees N or S of the equator where equator = 0

Coordinates (cont’d)

Longitude • Lines of longitude are meridians• Longitudinal lines are at a right angle to

latitudinal grid• 0° longitude is known as the prime meridian

Goes right through Royal Observatory in Greenwich, England

Greenwich Mean Time = ‘Universal Time’, when sun is directly above 0 longitude• Expressed as degrees E or W of prime meridian

where prime meridian = 0

Latitude and Longitude (cont’d)

Coordinates (cont’d)

Connected by 2 processes:evaporation and precipitation See fig 1.18 (Intro 7e) or 2.13 (Fund. 4e)

Earth’s water reservoirs:

Oceans 97.2%Lakes, rivers and inland seas 0.017%Glaciers 2.14%Atmosphere 0.001%Ground H20 0.61%Biosphere 0.005%

Earth’s WaterHow Earth's water reservoirs are connected

WORLDS WATER SOURCES:

• Layered system (like an onion, concentric regions)~ differentiation of mineral material

Not only Earth’s mineral material, but also:

1. hydrosphere2. biosphere3. atmosphere

Earth’s Structure

Classification according to chemical compositionEarth’s Structure (cont’d.)

4 concentric regions of mineral material:

1. crust2. mantle3. outer core - molten4. inner core - solid

1. Crust Two types:continental granite – composed of silicates rich in Na, K & Al

ocean basalt – composed of silicates rich in Ca, Mg & Fe• represents 0.4% of Earth’s mass• extends down to 75 km

Classification according to chemical compositionEarth’s Structure (cont’d.)

2. Mantle Three parts:uppermost/middle/innermost• Composed of Mg-Fe silicates• represents 68% of Earth’s mass• extends down from base of

crust to ~2,900 km

Classification according to chemical compositionEarth’s Structure (cont’d.)

3. Core Two parts:Outer Inner• Composed of Fe & Ni• Represents 28% of Earth’s

mass• Extends down from base of

mantle ~ 6400km

Classification according to chemical compositionEarth’s Structure (cont’d.)

1. lithosphere - rigid outer shell (crust & uppermost mantle)• 100 - 150km thick• does not change shape

(factor in temperature and pressure)Classification according to physical properties

Earth’s Structure (cont’d.)

4 concentric regions:

2. Asthenosphere - soft, flows over geologic time under the weight of the lithosphere (small fraction of middle mantle)• lithosphere ‘floats on top’• zone where magma formed• 200 – 350km thick• easily deformed, can be pushed down by overlying lithosphere –

“plastic” – tar or asphalt

Earth’s Structure (cont’d.)

3. Mesosphere - rigid but not as hard as lithosphere• higher temp than asthenosphere, but not molten because of

compression pressure• 4950km thick

Classification according to physical propertiesEarth’s Structure (cont’d.)

4. Core - outer is molten, inner is solid

Classification according to physical propertiesEarth’s Structure (cont’d.)

IsostacyPrinciple that dictates how different parts of the lithosphere stand in relation to each other in the vertical direction

• Continental crust less dense (granitic) therefore rises higher relative to ocean crust (basaltic)

• Continents move up and down depending on weight on top (i.e. from glaciers - ‘isostatic rebound’)

~ Continents pop up after glaciers melt

~ Canada and Scandinavia rising at a rate of 1m/100yrs because the glaciers are receding

Earth’s Structure (cont’d.)

Five oceans:1. Atlantic – shallowest, greatest number of adjacent seas-

regional seas: i.e. Gulf of Mexico, Caribbean, Mediterranean, North), has the largest freshwater input (i.e. Amazon, Congo, Mississippi)

2. Pacific – largest, deepest

3. Indian – smallest, muddiest

4. Arctic – covers N. Pole, saltiest

5. Southern Ocean – coldest, most productive

Earth’s Water (cont’d.)

(Some) OCEANS’ FACTS:

Our planet is actually the Ocean Planet - 77% of the Earth’s surface is covered by oceans and seas. However, less than 10% has been investigated.

Oceans provide more than 70% of oxygen we breathe

80% of world’s plant and animal species live in oceans

More than 60% of the current human population (5.8 billion) lives in the coastal zones (~60 km wide), the areas representing only 8% of the Earth surface!

‘Poorest of the poor’ - 1.1 billion people ‘survive’ on less than 1$/day 1 billion people rely on fish as the only daily source of protein

Global climate change and the humans’ well being depend on the conditions and health of the oceans;

Poverty, hunger, diseases as well as casualties from natural disasters can be alleviated by improving the health of the environment and by sustainable use and management of the coasts and oceans!