Origin of Earth and OceanOrigin of Earth and OceanScientific Observations and Explanations Scientific Observations and Explanations

on the Origin and Evolution of Earth’s on the Origin and Evolution of Earth’s OceanOcean

GEOL100 - Physical GeologyGEOL100 - Physical GeologyRay Rector - Instructor

Preview of Preview of TopicsTopics Origin of the UniverseOrigin of the Universe Origin of the Solar SystemOrigin of the Solar System Origin of Earth-Moon SystemOrigin of Earth-Moon System Origin of the Ocean and AtmosphereOrigin of the Ocean and Atmosphere Origin of LifeOrigin of Life The Age of the EarthThe Age of the Earth

A Twisted COSMIC TimescaleA Twisted COSMIC Timescale

Starting with the Big Bang event 13.7 billion Starting with the Big Bang event 13.7 billion years ago, and evolving to the present day.years ago, and evolving to the present day.

The Visible and Invisible The Visible and Invisible UniverseUniverse

13.7 Billion Years of Creation and Destruction13.7 Billion Years of Creation and Destruction

The Basic The Basic ComponentsComponents

Expanding SpaceExpanding Space 4 Fundamental Forces4 Fundamental Forces Energy - EMREnergy - EMR MatterMatter Dark energyDark energy Dark MatterDark Matter

How Much Stuff Is Out How Much Stuff Is Out There?There?

Position in the sky and the extent of the magnification Position in the sky and the extent of the magnification

Hubble Deep Field ImageHubble Deep Field Image

Every spot of light is a galaxy!

The Rough Stats:The Rough Stats:1) Size1) Size: 30 x 10: 30 x 1099 cubic light cubic light

yearsyears 1x101x1066 light yrs between light yrs between

galaxiesgalaxies

2) Matter2) Matter: 100 billion galaxies: 100 billion galaxies 1.6 x 101.6 x 106060 kilograms kilograms

@ 1.4 kg per cubic meter@ 1.4 kg per cubic meter

3) Only3) Only 0.0000000000000000000042 % 0.0000000000000000000042 % of the universe contains any of the universe contains any mattermatter

It’s a SUPER empty place!It’s a SUPER empty place!

Survey of Elements Found in Survey of Elements Found in UniverseUniverse

Questions:Questions: 1) What processes made the elements? 2) Why the three-step, relative abundance distribution of the elements?

92 Naturally-occurring elements

Predominantly Hydrogen and Helium

Lots of Carbon, Nitrogen, Oxygen, Silica, Sulfur, and common metals

Minor amounts of rare earth and very heavy elements

BIG BANG Theory -BIG BANG Theory - 14 Billion Years of Cosmic 14 Billion Years of Cosmic

EvolutionEvolution

The Big Bang Elements:The Big Bang Elements: Hydrogen and Helium were the two Hydrogen and Helium were the two major elements generated in cosmically-massive amounts soon major elements generated in cosmically-massive amounts soon after the initial Big Bang event – very little else.after the initial Big Bang event – very little else.

?

The Fate of Our Universe?The Fate of Our Universe?

Possible OutcomesPossible Outcomes1) The Big Freeze1) The Big Freeze

Expand forever Cold and Dark

2) The Big Crunch2) The Big Crunch CollapseCollapse Prelude to BB#2?Prelude to BB#2?

3) The Big Rip3) The Big Rip Runaway dark energyRunaway dark energy Anti-gravity tears Anti-gravity tears

apart all matter apart all matter

Galaxies – Gigantic Star ClustersGalaxies – Gigantic Star Clusters

Galaxies are “island universes” Galaxies are “island universes” where stars are born, live and die where stars are born, live and die

Gravity is the controlling force on Gravity is the controlling force on galaxy formation and evolutiongalaxy formation and evolution

Universe contains roughly 100 Universe contains roughly 100 billion starsbillion stars

Typical galaxy contains 100 billion Typical galaxy contains 100 billion starsstars

A typical star located in a galaxy is A typical star located in a galaxy is much like our Sunmuch like our Sun

Stars generate new elements during Stars generate new elements during fusion and novafusion and nova

All elements except for the very All elements except for the very light ones can only form inside starslight ones can only form inside stars

Our galaxy – the Milky Way – looks Our galaxy – the Milky Way – looks very much like our neighbor – the very much like our neighbor – the Andromeda galaxy.Andromeda galaxy.

Andromeda Galaxy

Circus of Galaxies

Key Points:Key Points:

Our Very Own Island Our Very Own Island UniverseUniverse

Milky Way Galaxy is 100 Milky Way Galaxy is 100 million light in diametermillion light in diameter

Our galaxy contains Our galaxy contains roughly 400 billion starsroughly 400 billion stars

Sun is a very typical Sun is a very typical star located in one of star located in one of the arms of the Milky the arms of the Milky Way GalaxyWay Galaxy

Other planetary Other planetary systems have been systems have been found in our galaxyfound in our galaxy

We arehere

Milky Way GalaxyMilky Way Galaxy

Nebula – Star NurseriesNebula – Star Nurseries Nebula are regions of dense Nebula are regions of dense

hot gases, stellar debris, and hot gases, stellar debris, and very young starsvery young stars

New stars and planetary New stars and planetary systems form from the both systems form from the both primordial matter and the primordial matter and the remnants of exploded stars remnants of exploded stars within nebulawithin nebula

Our solar system most likely Our solar system most likely formed in a nebula much like formed in a nebula much like this onethis one

Condensation Theory for star Condensation Theory for star and planet formationand planet formation

Carina Nebula

Observed Stellar Systems in the Observed Stellar Systems in the MakingMaking

The Trifid Nebula

Observations of Newly Observations of Newly Forming Stars Within a Forming Stars Within a Nebula CloudNebula Cloud

The Nebula Condensation Theory best explains The Nebula Condensation Theory best explains the formation of stellar systems such as oursthe formation of stellar systems such as ours

Stellar Fusion – The Element Stellar Fusion – The Element FactoryFactory

1) Normal Star = Helium

3) Red Supergiant Star = Neon through Iron

2) Red Giant Star = Carbon

The Fusion Process

Note: Stellar fusion processes generate the light to medium weight elements: from Helium (He) all the way up to Iron (Fe).

Three-Stage Star EvolutionThree-Stage Star Evolution

Supernova – Heavy Element FactorySupernova – Heavy Element Factory

Supernova Process

Collapse of Red Supergiants

Tycho-supernova

Stellare Implosion – Explosion ProcessStellare Implosion – Explosion Process

Note: Supernova processes generate the medium- to heavyweight elements: from Iron (Fe) all the way up to Uranium (U)

We arehere

Our Solar Our Solar SystemSystem

4 Inner Planets

Mercury

Venus

Earth

Mars

4 Outer Planets

Jupiter

Saturn

Uranus

Neptune

What about

poor little Pluto?

The Nebula The Nebula Condensation Condensation

TheoryTheory

Animation1

Animation2

Origin of the MoonOrigin of the Moon

Multiple Theories

Twin Planet Theory

Moon Capture Theory

Earth-Birthed Theory

Giant Impact Theory

Most Likely Origin of the Moon

Giant Impact Theory

Impact Sequence of Earth and Mars-size Body

The Giant Impact Theory best explains formation The Giant Impact Theory best explains formation of the moon, based on physical and chemical dataof the moon, based on physical and chemical data

Density Differentiation of Young Density Differentiation of Young EarthEarth

Proto-earth was homogenous

Proto-earth underwent complete melting due to accretion energy and radioactive decay

Heaviest elements sank down to form core – mainly iron and nickel

Medium weight elements formed mantle and crust– mainly silicate minerals

Lighter elements floated up to form ocean and atmosphere

Early-stage Differentiation ModelEarly-stage Differentiation Model

Composition and Structure of EarthComposition and Structure of Earth

Five Chemically Distinct Layers

Eight Physically Distinct Layers

Formation of the Earth’s Formation of the Earth’s Ocean and Atmosphere Ocean and Atmosphere

1) The Origins of Earth’s Atmosphere and Ocean are Closely Tied Together

2) The Composition of the Atmosphere Has Greatly Changed Over the Last Four Billion Years

3) The Composition of Ocean Initially Changed Over the First Billion Years But Has Since Remained Stable

Evolution of Earth’s Evolution of Earth’s AtmosphereAtmosphere

Three StagesThree Stages1) Primordial Atmosphere ???

Hydrogen and helium from original condensed nebula

Probably stripped away by early solar wind and heating

2) Secondary Atmosphere

Volcanic outgassing of volatiles from inside planet

Primarily water and carbon dioxide with sulphuric and hydrochloric acid, and methane

No free oxygen – a nasty, poisonous, acidic mixture

3) Modern Atmosphere Modification of earlier atmosphere by life processes

Removal of carbon dioxide and enrichment of free oxygen

The Oxygen The Oxygen RevolutionRevolution

1)1) Photosynthetic marine Photosynthetic marine bacteria begin releasing bacteria begin releasing oxygen (Ooxygen (O22) into the ocean ) into the ocean and the atmosphere by 3 and the atmosphere by 3 billion years agobillion years ago

2) By about 2 billion years ago, sufficient 2) By about 2 billion years ago, sufficient OO22 in atmosphere to oxidize (rust) rocks in atmosphere to oxidize (rust) rocks

Protects Earth’s surface from ultraviolet solar radiationProtects Earth’s surface from ultraviolet solar radiation

Photosynthesizing Photosynthesizing CyanobacteriaCyanobacteria

3) Also by 2 billion years ago, protective ozone (O3) Also by 2 billion years ago, protective ozone (O33) layer ) layer

built up in atmospherebuilt up in atmosphere

4) By about 500 million years ago, O4) By about 500 million years ago, O22 levels in atmosphere levels in atmosphere

approach today’s levelsapproach today’s levels

Original Sources of Ocean Original Sources of Ocean WaterWater

Two Primary SourcesTwo Primary Sources

1) Volcanic Outgassing

Majority Amount of H20

2) Comet Impacts

Minority Amount of H20

Outgassing of Interior

Comet Strikes

Water initially collected from these Water initially collected from these two sources as part of a thick, dense two sources as part of a thick, dense atmosphere that later condensed and atmosphere that later condensed and precipitated into surface watersprecipitated into surface waters

Water from OutgassingWater from OutgassingMajority Primary Source = Volcanic Outgassing

Composition of volcanic gases for three volcanoes

Formation of Our OceanFormation of Our OceanThree Phase HistoryThree Phase History

1) Initially there was only water Initially there was only water vapor in atmospherevapor in atmosphere – Air and ground surface too hot for liquid

2) Cooling of atmosphere led to Cooling of atmosphere led to condensation and raincondensation and rain – Ground surface still too hot for pooling

3) Further cooling of ground Further cooling of ground surface finally led to the surface finally led to the accumulation of liquid water on accumulation of liquid water on surfacesurface – Ocean formed by 4 billion years ago

1)

2)

3)

The Twisted Geological The Twisted Geological TimescaleTimescale

Video Review of Big Bang to Present Day - YouTube

Timeline of Earth’s First Billion Timeline of Earth’s First Billion YearsYears

First Organisms

End of Bombardment

Oldest Existing Rocks

Formation of Ocean

Formation of Moon

Formation of Earth and Solar System

The Geological The Geological TimescaleTimescale

Key Ideas:Key Ideas: Originally based on Originally based on relative dating and relative dating and the use of age-the use of age-specific fossils specific fossils

Periods separated Periods separated by mass extinction by mass extinction events events

Numeric ages Numeric ages derived from derived from radiometric analysis radiometric analysis of igneous rocks of igneous rocks found within the found within the stratigraphic recordstratigraphic record

The Origin of Life on The Origin of Life on EarthEarth

Why Life on Earth? The Why Life on Earth? The ConditionsConditions

Mars

Venus

Did Life Did Life Start in the Start in the

Ocean?Ocean?

1) Earliest life forms found are 1) Earliest life forms found are fossilized bacteria in rocks fossilized bacteria in rocks dated 3.5 billion years old.dated 3.5 billion years old.

2) Found in both shallow and 2) Found in both shallow and deep ocean sedimentary deep ocean sedimentary rocks.rocks.

3) Exposed land surfaces back 3) Exposed land surfaces back then were barren and hellish.then were barren and hellish.

4) The ocean was much 4) The ocean was much milder, particularly the deep milder, particularly the deep ocean.ocean.

Stromatolites Microfossils

Conditions for Sparking Conditions for Sparking LifeLife

Lab ExperimentsLab Experiments1) Simulate early Earth conditions

2) Formed life-giving organic chemicals

3) No actual life created

4) Still an unsolved mystery

Comet Impacts?Comet Impacts?

5) Recent studies point to comet impacts

Most Likely Cradle for Life on Most Likely Cradle for Life on Earth?Earth?

Deep Sea Hydrothermal Vents?Deep Sea Hydrothermal Vents?

Warm, water-rich environment

Chemical-rich volcanic fluids

Protected from harsh surface

Class DiscussionClass Discussion

Review of Study Review of Study TopicsTopics

The Origin of Universe – The Origin of Universe – Energy and MatterEnergy and Matter

The Origin of the Solar SystemThe Origin of the Solar System Origin of Earth-Moon SystemOrigin of Earth-Moon System Origin of the AtmosphereOrigin of the Atmosphere Origin of the Ocean Origin of the Ocean Origin of the LifeOrigin of the Life

Preparation for Next Preparation for Next MeetingMeeting

Next Meeting TopicsNext Meeting Topics

1) Deep Time and The Age of Earth 1) Deep Time and The Age of Earth 2) Continental Drift Hypothesis2) Continental Drift Hypothesis 3) The Plate Tectonic Theory3) The Plate Tectonic Theory

Homework Assignment:Homework Assignment: Read Chapter 2 in Textbook Study the Instructor’s Website

@ www.geoscirocks.com Lecture Notes PowerPoint ER Videos 5 and 6

Continental Drift HypothesisContinental Drift Hypothesis

Alfred Wegener (1880-1930)