PENT Geology

                                                                    

Objectives

•Composition of the Earth

•Should be able to identify every rock you pick up

•Or at least you will know HOW to go about identifying it

•A bit of the Earth’s history and the power that drives volcanoes and earthquakes

New theories

•Plate Tectonics – rigid “skin” of the earth in constant motion (but very very slow)

•Dinosaurs existed & numerous other creatures

•Ice Ages: Manitoba and most of Canada covered with ice until only recently
  Periodic asteroid hits that wipe out living forms, mountains are created & later destroyed by erosion

Dark areas: rifts with volcanic mountains

Earth science

•Necessary to see how “the Earth works”, esp. now with climate change (Earth under stress?), repair   damage, be active to protect, teach with examples, go on field trips

•Hurricanes (some human factor),

    tsunamis (not frequent, but always happen),

    volcanoes (deadly, but life-giving)

This course: Geology

•Geo = earth, logos = speech, study, science   Scientific words are GREEK

•Weather is part of Geography

What we study

•Make-up of Earth, volcanoes, earthquakes

•2 Labs. on Minerals, 3 labs on the types of Rocks (igneous, sedimentary, metamorphic)

•Examples of minerals: salt, diamond, graphite

•Examples of rocks: limestone, granite, basalt

New theory : MOON BLAST theory

Earth has a secret!

Energy inside earth? Yes!

•Responsible for events like : volcanoes, earthquakes, geysers, slow movement of crust that creates mountains (at a rate of a growing finger nail)

•Theory of the origin of the earth : explains energy “trapped” in the interior

How did it all start ?

•Gas and dust particles floating in space from previously existing stars that died and blew up

•Particles accumulate by gravity

•Particles trying to get into the center eventually swirl like in a hurricane

•They combine, heat up and form a new star

•Left-over particles form the planets

•All planets continue to move around the star

Theory on the Origin of Earth

•Stages :

     1. dustball

     2. fireball

     3. differentiation by density

     4. cooling

     5. later changes (life forms

         change, mountains form)

•Layers found on earth:

     atmosphere

     crust  (ign/sedim/meta)

     mantle

     core

                         age             origin                explanation                 future

•Universe  13.7 b.y.     Bing Bang  all stars move away       expansion

•Solar System  4.6 b.y. nebula                dust+gas                  explodes

                      -----------------------------

•Star : is born -  burns gas  - dies when runs out

                                                           of gas

“Dating” rocks

•Radioactivity discovered early in 1900’s accidentally by Madame Currie of Paris

•A radioactive element like uranium decays at a constant rate to form lead. During the decay, it releases electrons, protons and powerful gamma rays, detectable with a Geiger Counter (scintillometer)

•The ratio of U / Pb in the rock (extremely low concentrations) would be proportional to the age of the rock

•Plate Tectonics : 30 year old theory

•Heat rises under thin ocean & lava spreads

•Meets land & subducts

•All surface in constant motion

•Geologic processes take place slowly with the speed at which fingers nails grow (a few cm/year

•Geologic time is enormous

Organic Evolution: Life on this planet is marine in origin

.   Ingredients may have come to this planet from comets, meteorites

•First life in black smokers (still around today)

•Photosynthesis (plants like bacteria) later

•Single cell plants(first) & animals (later)

•Invertebrates (no hard parts, later skeletons)

•Vertebrates: Fish, first vertebrate

•Amphibian, reptile(some warm-blood), mammal, bird

•Homo sapiens emerged from the Ice Age

Life

•Invertebrates: most abundant life on the planet, includes insects, clams, snails, etc

•Have external skeleton

•Vertebrates invented later to be able to travel in the sea (originally)

•Conditions were good for life to move onto land about 400 m.y. ago (ozone layer formed)

•It took 4 b.y to build the ozone, but only 50 years for humans to destroy it partially (freon)

•Fish to amphibian was a relatively simple transition

•Amphibian to reptile (100 % land animal) was a big step

•Reptiles made tremendous advances, like the amniotic egg, warm blood, teeth for chewing

•These were passed on to the mammals, such as us

•We are grateful to the dinosaurs for all these advances (Hollywood will never teach you these simple facts, because the producers are NOT educated)

•On this planet life is Carbon-based with sulfur, nitrogen, etc: all products of volcanoes

•In other words, life was created by the ingredients that are emitted by volcanoes

•Most volcanoes are under the sea, so life started there

•Life elsewhere in the universe maybe different, such as silicon-based (reportedly, the “grays”)

•Reproduction was by division (offspring identical to parent), then branched out into sexual reproduction from about 1.5 billion years ago

•The life on this planet maybe very rare in the universe

•Judging by the interest shown by other civilizations – the media obscures “strange” events, such as crop circles & flying saucers because they think most people are stupid

•You can ask the astronauts about the strange events they encountered. That is why no one wants or volunteers to fly to the moon again!

Scientific method in all sciences

•Observe and make an explanation (hypothesis, theory, law)

•Uniformity (“the present is the key to the past”): only law in geology

•Once in a while dramatic disruption of life by the fall of an asteroid (large meteorite)

•Earth is a closed system (can’t export pollution)

Now

•Humans have been able to change the planet’s atmosphere & kill off some of the ozone layer (protective layer from UV radiation of the sun)

•Need to repair damage or face the consequences

•Have to protect the environment (it is “our only home”, some of my students wrote in essays/projects)

Meteorites

•They fall from the sky coming from the Asteroid Belt (between Mars and Jupiter)

•Most have been unchanged since the formation of the Solar System

•They contain information about the origin of the Solar System

•They are very valuable and are worth a lot of money (at least $ 10,000) to whoever finds one

•Meteorites are named after the nearest community in which they fall or are found (they are called  “finds”)

•Rarely, a meteorite is seen to fall (a “fall”)

•Only about 70 have been found in Canada, so start looking

The biggest known fall: Sikhote Alin, Russia, 1947 (painting, no cameras then)

2001, near Winnipeg

14-year old hit in the foot in the U.K.

The “eye of Quebec”
Manicouagan crater

New Science of Meteorites

•Fascinating facts about them

•Their speed: min. of 11 km/sec up to a max. of 70 km/sec. Average 30 km /sec (2 sec to Wpg)

•Worth at least $ 10,000 and you still owe it!  (in Canada): You lease it to a museum!

•Analysis can give information about birth of our Solar System

this was part of the dinosaur killer!

Comet

Comet Shoemaker -Levy 9 hit Jupiter in 1994 after it broke in 22 pieces

The collision with one of these fragments made a blast (light on Jupiter) bigger than the Earth!
Manitoba craters

•Gypsumville (St. Martin): biggest in western Canada, 40 km across

•West Hawk Lake (near Ontario border): It is 100 m deep with another 100 m of mud and 330 m broken up rock

•A BUNTEP student found a small crater in his trap line (probably the third in Manitoba)

Video: The Miracle Planet

•Origin of the solar system

•Meteorites on earth: Chicago

•Murchison meteorite: water, aminoacids

•Manicouagan (The “eye of Quebec”)

•Planetesimals, Bombardment, Fireball

•First rain

•K/T boundary, clay with iridium

•Mexico meteorites

•Famous 1972 “near –miss”

Video: The Heat Within

•Yellowstone

•Witwatersrand, 3 km deep mine, temp. at 52 degrees C

•Iceland: land of volcanoes (besides the ice= frozen ocean as one approaches the island)

•1974: started exploring ocean floor

•Black smokers

•East African Rift

•Himalayas: fossils

•Purification of minerals : Cu in Cyprus

•Andes 8,000 km long: “copper mountains”

Geological History of Manitoba   ß------- search in google

•In poster form

Minerals

MINERALS (not rocks!)

•92 chemical elements

•Made of atoms: smallest possible unit. Can be seen under 17X million. Impossible to split? Atom bomb! (mass turns into energy)

•Electrons (means, amber) in specific orbits, mostly empty space

•If less than 8 in outer orbit, substance is unstable, forms compounds

•covalent (diamond), ionic (salt), metallic (copper), van de Waals (graphite)

Diamond

Diamonds measured in carats

•Here are samples of carats

•The pods in a chocolate bean (carob) found in Greece – makes herb chocolate, chips as well

•Each pod weighs exactly 0.2 gram

•Used as a measure of weight for gems (not for gold anymore)

Museum in Toronto changed appearance

Natural, solid, inorganic, unique structure/composition

•Crystal (“ice”): solid form

•Color, streak (plate, hematite)

•cleavage, fracture (conchoidal)

•hardness (Mohs)

•S.G. = wt/ loss in wt, or equal volume of water

•Graphite 2

•Diamond 3.5

•Silver      10

•Gold        19

Miscellaneous

•Acid test: calcite / dolomite

•Magnetism : magnetite / pyrrhotite

•Taste : halite / potash

•Double refraction : calcite

•Twinning : plagioclase

•Elastic : only micas

Glass breaks like that, also quartz (CONCHOIDAL fracture)

Hematite: BLOODSTONE, it bleeds when scratched, but does not cry

FIREROCK (pyrite) or Fool's gold : sparks when hit !

Specific gravity / Archimedes principle or Law of Buoyancy

1.King Hieron gives a jeweller a bar of gold to make into a crown

2.When the crown was delivered, the king measured the mass. It had the same mass as the gold bar

3.The king is suspicious. He asks Archimedes.

4.A. notices that the amount of water that overflowed the tub was proportional to the amount of his body that was submerged

No one knows about density then

Archimedes reasoned that

1.If the gold bar and the crown had the same mass, and

2.If both had the same volume,

Then, the crown was pure gold

Density = weight in air / loss in weight when immersed in water
                                                                or,  weight of water displaced

Archimedes reasoned that

The volume of water displaced by the crown should be the same as the volume of water displaced by the bar of gold

However, the crown displaced twice the amount of water than the gold bar(it had lower density, consisted of less dense material)

•Water displacement: an object immersed in water will displace a volume of water equal to the volume of that object

•Water Bridge: A ship always displaces an amount of water that weighs the same as the ship

OTHER inventions byArchimedes: screw

•Used to bring water up

•Essential for irrigation in Egypt & elsewhere

Other inventions: Mirrors, Levers

Earth’s crust

•98.5 % made up of only 8 elements

•75 % of these are OXYGEN, then SILICON

•Rest are Fe, Mg, K, Na, Ca, Al

•Most common compounds are Silicates, or rock-forming minerals

•Basic unit : 1 Si, 3 O atoms

SILICATES  
      units          mineral        crystal form   color

•Isolated          Olivine           granular        green

•Single chains  pyroxene    long crystals   green

•Double chains amphibole long cry black/green

•Sheets             micas           layers            various

•3D                    quartz        like boxes        various

•                      orthoclase    ‘’      “        pink/white

•                      plagioclase   “       “      white/black

Major Elements in Silicates & their symbols

•Iron  Fe

•Magnesium    Mg

•Sodium     Na

•Calcium    Ca

•Potassium  K

•Aluminum   Al

Elements in Silicates

•Olivine                                     Mg     Fe

•Amphibole, Pyroxene           Mg    Fe

•Micas                                      K, Na, Ca 

•Orthoclase                             K

•Plagioclase                             Na, Ca

Typical multiple-choice question on minerals

•This white, soft mineral has glassy luster, basal cleavage, white streak and is used in wall construction.

                          a) quartz

                          b) calcite

                          c) gypsum

                          d) epidote

                          e) pyrite

Previously melted

IGNEOUS ROCKS

Video: St. Elmo's Fire

Plane travels from Jakarta, Indonesia to Perth, Australia

It hit St. Elmo's Fire, # 4 engine stops, then # 1,2,3 engines stop! Very quiet in the cabin!
It turns back to Jakarta, but is unable to cross the mountains until some engines re-start.
Just before it hit the ocean the #4 engine restarts, then the other 3 engines re-start together.

While approaching the airport, the engines stop again! Also, the front windows have been etched and one can't see through, but it lands safely.

The engines were taken out and examined thoroughly. Dust from the volcano entered the engines and melted, crusting up the engine so that it could not get enough air and oxygen to function. When the dead engine cooled enough the crusted material cooled and broke off and fell outside the engine, so the engine could restart.

•80 % of all rocks, used to be molten

•Magma : molten silicates + gases + metals

•All gases (except oxygen) & all metals come with magma

•Geothermal gradient : 30 ‘ C / km of depth

•Entire interior should be molten, but no room

•Any movement below ~ 35 km creates magma

Centigrade (Celsius) scale

•Metric (French, brought from Egypt by Napoleon)

•Water freezes at 0 degrees

•Water boils at 100 degrees

•Divide scale into hundred divisions

•On that scale magma melts at ~ 1,000 degrees

•Our body temperature is 36.6 degrees

•So, keep away from magma !!

Hypothermia (just to think in metric)

•Erika Nordby, Edmonton, 2001         Karlee Kosolofski, Rouleau, Sask. 1994    Brittany Eichel, W.Virg. 1991

•1 year-old                                                2    year old                                                    3 year old

•Toes frozen together                            tried to follow   her dad to work                 2.5 hours at – 3 ‘ C

•Outside for 3-4 hours                           winter coat + boots over pyjamas               only underwear

•Took doctors 1 ½ hours to get            found 6 hours later at – 22’C                        lost a toe

•the heart beating again                        body almost frozen solid

•slowed metabolism enough        legs were frozen like blocks of ice

•it didn’t need normal blood flow        left leg amputated, bone surgery, skin grafts

•                                                                   14 ‘ C :  lowest ever recorded

• 

•Hypothermia made first heart transplant possible

•Wilfred Bigelow (Brandon) in 1950 found how to safely lower the body’s need for oxygen by lowering the body’s temperature. Also developed the first pacemaker.

•Revolutionized heart surgery which is routine operation today.

Magma cools

•Interior : intrusive, plutonic

•Exterior : extrusive, volcanic

•TEXTURE: size of crystals

             - small crystals means it cooled quickly

             - large crystals means it cooled slowly

             - glassy means extremely fast

               (that is how window glass is made)

Crystallization of magma

•When temperature drops

•Olivine : first to appear

•Followed by other dark minerals (pyroxene, amphibole, Ca-rich plagioclase, biotite)

•Followed by light colored minerals ( Na-rich plagioclase, orthoclase, muscovite)

•Quartz: last to crystallize

•Impossible to have olivine and quartz in the same rock

•Igneous rock would have

               - high temperature minerals

              -  intermediate temperature minerals

  or       -  low temperature minerals

Can’t have them all in the same rock !

Porphyry

•Originally, the “purple dye” taken from some clams in the eastern Mediterranean

•Red or purple color

•Byzantine Emperors were dressed in red or purple color

•Red or purple columns of porphyry in great demand during the early years of Christianity, reserved for the first churches. Found only in one place in the Egyptian desert

 NOTE: all government buildings in Regina constructed with granite porphyry!

Pegmatites : rare

•Extremely slow cooling of magma

•Crystals accumulate in layers

•Beryllium (emeralds)- Dryden, Ont.

•Platinum: only mine in S. Africa, for seat belts

•Titanium: 1^st find in Cross Lake, for zippers, tennis rackets, bicycles, airplanes, paints, etc

•Chromium: for car bumpers, etc

•Vanadium: for making steel

Pegmatites

•Many in SE Manitoba

•Mine at Bernic Lake (near Lac Du Bonnet)

•Produces unusual metals like

             - lithium: for batteries, stomach pills

             - cesium: for accurate clocks, electronics

                             see also Cesium festival

             - tantalum: for bone repairs

             - columbium: for electronics

Classification of igneous rocks

•Based on texture & minerals present

•Light colored – intermediate – dark

•Commonest : granite (makes continents) &

                             basalt (makes the ocean floor)

•Rare on surface: Ultramafic, makes up the mantle (basically, olivine + some diamonds)

Granite : very hard rock

Trango Tower, Pakistan

Cooling of mafic (black) magma

•Columns

•pillows

example: Giants Causeway, N. Ireland (basalt)

Shapes of intrusions

•Thin : dike or sill

•Laccolith : mushroom shaped

•Volcanic pipe

•Pluton or batholith

                      Other Features:

•Chilled margins

•Xenoliths (foreign rocks)

Why granite so common?

•Granite found only on Earth

•No granite when Earth was created. Produced by plate tectonic processes

•Contains small amount of radiation (uranium)

•Origin: Widespread melting during formation of mountains, collisions of continents and subduction of ocean floor

•Every mountain has a core of granite

Magma to the surface

Volcanoes

•Don’t kill people

•It is the people who get on their way

•Respect it and move away until it is safe to go back

•Its power is tremendous

Volcanism

•~ 50 eruptions per year

•Most volcanoes under the sea

•Fissures along 70,000 km Rift system of ocean-spreading ridges-only place above water is Iceland

•Also, volcanoes in subduction zones &

•About 25 “hot spots”: Hawaii, Yellowstone, Galapagos, Iceland, many in Africa

Disaster v. Rebirth (Blessing)

•Lava will burn, toxic gases will suffocate, etc

•But, new rock, land, soil (very productive)

•Gases: water, carbon, sulfur, nitrogen, halogens (Cl, F, I), noble (Ar, Ne, He)

•Metals in black smokers (Au, Ag, Cu, Zn, Ni, etc)

•Diamonds

What comes out?

•Lava that flows or is sticky like honey

•Stones of all sizes from ash to bombs

•Gases (they make magma light & moving upwards)

Mt. Unzen, Japan: 44 people trapped (cloud moves 100 km/hour DOWN the hill)

The Blue Lagoon, Iceland (resembles hot spring, but is waste product of geothermal plant

sand baths

Martinique, 1904: big disaster, whole town destroyed , everyone killed = a mistake)

Vesuvius, Italy: threatens 2 million people living around it

Volcanic sunsets (lots of dust in the air)

Composition of magma

On continent   On continent  near ocean        On ocean floor           In mantle

----------------      ---------------------------------          ------------------             ------------

rich in quartz              some quartz                      low in quartz               no quartz

rich in gases                some gases                        low in gases                 no gases

light colored             intermediate                     dark colored                dark green

viscous (gases            can be explosive              fluidy (gases                      ----

cannot escape)                                                      can escape)                      

very explosive                                                        not explosive

Landforms

•Shield: flat, basalt, fluidy, aa, pahoehoe, pillow

•Dome: steep, rhyolite, viscous, St. Helens

•Cinder cone: steep, rhyolite, pyroclastic, explosive

•Composite: lava & pyroclastics, Mt. Fuji

•Caldera: crater, collapsed volcano, Toba, Oregon

pahoehoe

Aa

Basalt pillows under the sea

Accumulate on the ocean floor

Can be found on the surface: these are pillows from the Archean, 2.8 billion years old

Effects

•Lava flow predictable – throw water to it & will stop moving!

•Pyroclastics: dangerous, ash + stones + gases all hot : Nuee ardente (pyroclastic flow) heavier-than-air, flows downhill at 100 km/h

•Martinique, 1904: 40,000 died + 1 survived

•Pompei, 79 AD: gypsum bodies

•Hot ash mixed with rain or melting snow= lahar, like cement—Armero 1985

•Phreatic eruption: Krakatoa 1883 magma + sea waterà superheated water, extr.  Violent

•Tremendous noise to Africa, Australia

•Atlantis (Santorini), 1650 BC destroyed Minoan civilization- no skeletons, gold, therefore people escaped & went to America (?)

•Gases only: Africa, 1986 CO2 escaped from lake suffocating people-animals

Santorini, Greece (Atlantis?): half of the island still here

Gypsum casts - Vesuvius

bread

Nearest volcano to Manitoba

Devil’s Tower, Wyoming

Prediction

•Rhythmic tremors

•Unusual animal behavior

•Hot springs, smoking

•Sulfur gases indicating magma

VIDEOS ON VOLCANOES (some of these will be shown)

Video: Mt. Pinatubo

•June 12, 1991. It was asleep for 600 years!

•Largest eruption of 20^th century: 5-8 cu km of ash, that is 10 X that from St. Helen’s. Ash blocked sunlight for 5 years. Lahar deposits up to 200 m thick

•Warnings:

-frequent earthquakes

-increase in gas emissions esp. sulfur

-appearance of magma on the surface (a magma blob forming a small steep hill)

Lahars from mixing of ash with rain from typhoon

Video: Forces of nature

•Explosions of lava

•Hawaiian volcanoes: erupting since 1983

•Pahoehoe: ropy

•Aa: crusty, sharp

•Pour water to stop lava

•Mt. Vesuvius, Pompei, 2,000 buried alive

•Martinique : pyroclastic flow

•1980: Mt. St. Helen’s, mountain blows up, mudflow

Video: Deadliest volcanoes on Earth

•Mt. St. Helen’s: eruption for 9 hours, geologist 9 km away did not survive

•Mt. Rainier: dormant for 100 years, most dangerous in N. America

•Mt. Unzen, Japan: pyroclastic flow coming down at 100 km/hour !  Run!

•Indonesia:

•Krakatoa, 1883 (24X nuclear blast) killed 36,000 by tsunamis, 1925

.   Golongo

.   Tambora, 1815 (“year without a summer”), cold weather, famine

.   Toba, 75,000 years ago a global catastrophy that reduced human population from 700,000 to 10,000. Finding supported by DNA evidence: this disaster is the reason why humans are only one species today

•A big eruption throws lots of dust into the air blocking the sun

•A nuclear winter scenario

•Temperature drops, crops fail, massive famine

•Where will the next big eruption be?

•Mexico City, Montserrat, or in your own backyard?

St. Pierre, Martinique, 1902
a sequence of events

•Early April : smoke

•April 23  : cinders

•April 25 : could of rocks & ashes

•May 2 : pillar of dense black smoke falls like snow

•May 4 : ash rain, very dense. Lost electricity

•May 5 : explosion louder than thunder

•May 7 : Two fiery craters glowing like blast furnaces. Dark ash cloud

•May 8 : 7:52 am: Enormous column of black smoke moved incredibly fast. It filled the whole sky. It became dark. Cloud reached town in less than a minute. Superheated steam and gases (“a glowing avalanche”) or nuee ardente exploded sideways

West coast volcanoes

Mt. Meager     180 km N of Vancouver: hot springs

                                                                Last activity 2,400 y. ago

Mt. Garibaldi     50 km N of Vancouver: landslides,

                                                               last activity 13,000 y. ago

Mt. Baker (“sleeping giant”)minor eruption in 1870

                                          Avalanche reached Vancouver 7,000 y. ago

Mt. Rainier                              most dangerous in N.A.

Mt. St. Helen’s                             last eruption in 1980

                                                      Mudflows reached 120 km away

Video: The Kraffts (Maurice & Katia)

•Travelled 9 months/year for 20 years

•Kilauea volcano: lava lake in a depression

•Lungay, Africa: black lava like mud, very fluidy

•Indonesia: filmed nuee ardente in action, even at night

•Stromboli: frequent eruptions

•Heimay: cooled flow with water

•Indonesia: sulfuric acid lake, skin dissolved

•Armero: people did not trust volcanologists, but in Indonesia people evacuated & disaster averted

Video: Kilimanjaro, Tanzania

•Tallest free-standing mountain at 4,600 m (above clouds)

•Has its own micro-climate, with unique species of plants / animals. Soil is fertile from melting snow and supports a rainforest. Produces coffee & bananas.

•Last eruption 300,000 years ago

•Hot vent activity today, must be magma ~ 120m below. However, the glaciers on top are melting fast, 80% of icefield has gone. Maybe the rest will evaporate and the animal/plant life below will disappear

Video: Vesuvius
National Geographic

•50 eruptions since Roman Empire

•Today, 2 million people live around the volcano. It is monitored

•Pompei, 79 AD: people thought it was a mountain. Most fled. It was soft pumice rock to dig out, but in Herculaneum it was hard like cement. Romans were cremated, skeletons are rare. Only those trapped in Pompei, plaster was injected to make casts of the victims

•Eruption had 2 stages: Ash & pumice for 18 hours first followed by the collapse of ash & pyroclastic flows entombed the people. The surges were most dangerous, violent like from a nuclear blast

•Pliny the Elder wrote down the events

•Was the biggest eruption for 4,000 years

•24 Aug. 79 AD 4 m of ash + pumice. Most people survived that. Magma turns into foam & magma around gas turns into glass. It fell at a rate of 20 cm / hour

•There were forests on the mountain, it had not erupted for a long time (400 years)

•Investigation discovered surges of pyroclastic flows. People died by suffocation, they had no injuries, there was a lack of oxygen. People had their mouth open upwards. Six surge layers were found. Surge # 4 killed most people at Pompei. It deposited a layer 5-10 cm thick like concrete. It formed with heat at 100 ‘C (no bacteria in the soil surrounding the bodies) with ash. It was like a jet blast.

•1997 in Monserrat: a pyroclastic surge killed 20 people – island deserted since

•Final surge was at 8 am into Herculaneum. Pliny the Elder was found 2 days later. He looked as if he was asleep.

•Probably 10,000 died in the countryside from the final surge

•No excavations have been done outside Pompei, so the dead have not been found yet

Video: St. Helen's eruption, 1980

Tomb of St. Helen in Italy


May 18th, 1980

Biggest eruption in modern times
Largest landslide in recorded history
Cascadia mountain belt
Called “fire mountain” by the native
Last activity 1857
First sign, an earthquake on March 20th
Small explosion on Mar. 27
Brings curiosity to people

Scientists (not specialists) started studying

Harmonic tremors: magma on its way up

“The bulge” formed on northern side

May 18: earthquake under the bulge, caused landslide (avalanche) plus explosion 700 X bigger than atom bomb

Lateral blast (pyroclastic flow) overtaken landslide

Black ash made day into night 

Eruption pumped ash into the air for 9 hours

57 people died 

Video: The Ring of Fire

•“Our Earth was born of Fire”

•Volcanoes threw out the gases that formed air/sea

•400 volcanoes around the Pacific

•Hawaii: volcanic lake

•San Fransisco: 1906, 1989 (1.5 m slip)

•Mt. St. Helen’s

•Mt. Sikurajima, city of Sigosima, 1914 eruption

•Japan: 50 volcanoes

•Geothermal  energy: health spas

•Indonesia: 140 volcanoes, temple of Burabadur, sulfur miners

•Bali: Ganun Lagun (sacred mt.) 1916 eruption

•Hawaii: tallest mountain on earth (10 km)

•In less than 1 year after eruption life emerges

•Earth is alive!

It is breaking down on the surface

WEATHERING

•Any rock exposed breaks down by mechanical / chemical means to form

1. Sediment + 2. solubles in water

•Life uses solubles to form skeletons and blood

{in the old days iron - Fe -was also soluble in water, but not since oxygen appeared}

MECHANICAL WEATHERING

•Frost wedging: water expands into ice ~ 10%, it cracks rock/pavement. Tremendous power

•Root wedging

•Extreme temperatures

•Wind

•Exfoliation (pressure release) like onion skin

    Rock climbers know about this

-  Salt crystal growth

CHEMICAL WEATHERING

•Water and acids (acid rain)

•Products of weathering of silicates:

mineral                   insoluble                         soluble

olivine                   iron oxides (rust)                Mg

micas, pyroxene, iron,Al oxides,clays      Mg,K,Ca,Na

amphibole

feldspars                      clays                          K,Na,Ca

quartz                       (quartz)                         (silica)

                              ----------------                 ---------------

                           remain on land               into the sea

CLAYS (recently found on Mars as well)

•a set of new minerals form as a result of weathering (not found in other planets)

•Used in medicine pills- eat them all the time

•Nutrients (that plants need) attach themselves to clays in the soil

•We refer to clays as mud or dirt, esp. when wet & slippery

ACID   RAIN

•Accelerates chemical weathering

•Source is exhaust of all kinds of engines

A.Carbon gases: from engines

B.Sulfur gases: from engines

C.Nitrogen gases: from heated up air around engines

Trees die, lakes/sea become acidic. Fish die from eating colloidal Al oxides

SOILS

•Depends on temperature & precipitation

•Layered by action of water into

   A horizon : dark, organic-rich, zone of leaching

   B horizon: brown, zone of accumulation

   C horizon: broken-up rock with soil

Types of soils

precipitation increases

    --------------------------------------- >>>> ------------------------------------------------

                                                                                                          Laterite (red brick)

                                                                                                     thin  A, clay-rich B+ Fe

Temp.          Desert                                     Prairie

Increases    over-fertilized     thick A, clay-rich B, tall grasses              Podzol

      up         productive, if watered 

                                                                  Chernozem               white A, in mountains

                                                                 short grasses            

                                                                                                                  Tundra

                                                                                                       permafrost, immature

Soil Productivity

•Very valuable resource, need to prevent erosion by keeping roots in after harvest & erect “shelter belts”

•Fertilizers needed to replenish it after use:

Nitrogen: from ammonium sulfate, also from the air(if soil is broken up)

Sulfur: from ammonium sulfate, gypsum

Potassium: from wood ashes, potash (plants take K2O)

Phosphorus: from manure, sewage, guano

   “ no animal or plant can exist without phosphorus”

Sedimentary Rocks

•From products of weathering (2 types):

 - sediment (soil) -------à  Clastic sed. rocks

 - solubles ----------à Chemical sed. rocks

Lithification : 2-stage process

1. Compaction + 2.cementation to form a sedimentary rock from sediment (long process)

Grand Canyon, Arizona

•Any sed. rock may contain fossils

Fossils – observed around the building:

                     Corals, brachiopods, Cephalopods

Corals are animals

Marine reptiles of Manitoba

Early mammals (bigger than elephant)

Cadborosaurus of BC (resembles a snake)

Ammonite: skeleton up to 10 m

Quebec “fisherman”: clams, clams, clams, lots of people eat them(esp. people living by the sea)

Clastic sedimentary rocks

•Classified according to size of grains

   large rounded stones : conglomerate

   large angular stones : breccia

   sand –size stones : sandstone

   silt – size stones : siltstone

   clay-size (not visible) : mudstone & shale

Chemical sedimentary rocks

•Classified according to chemical substance present :

Most common is Limestone, made of calcite (chalk is a variety, made from skeletons of microscopic plants) also, Dolomite, made of dolomite

These rocks are usually made up of skeletons of visible or microscopic animals / plants

blocks of foraminifera limestone – make the PYRAMIDS OF Egypt (2.5 million blocks for one)

The OCEAN EVAPORATES

Evaporites: from chemicals precipitating after the sea water evaporates:

Halite: common salt

Potash: fertilizer (Saskatchewan)

gypsum, anhydrite, selenite : fertilizer, “safe food additive”

borax: in soap detergents (TV rock)

sodium sulfate: in soap detergents

•Chert, jasper, flint, diatomaceous earth: made up of quartz which used to be skeletons of microscopic animals

•Diatomaceous earth: insect repellent & liquid absorbant (no reaction to acid, although it looks like chalk)

•Iron Formation: layers of magnetite & chert. Formed before oxygen was part of the air (today, oxygen would attack iron & turn it into iron oxide or rust)

•Iron was soluble in water in ancient times and was part of the sea and formed the blood of animals

•Rock attracts magnet, frequently red or black

Watrous lake, Sask.

Salts dissolved in lakes, like the Dead Sea heal many things including smallpox!

•Remains of ancient sea whose deposits are found under the surface, about 1 km deep

•Brought to the surface by movement of groundwater

•Watrous (“waters make wonders”, or “doctors” lake) is a spa that has cured the sick for a very long time

•The “Royal Inquiry” whitewashed it

Organic remains

•Buried with sediment change under pressure

•Plant remains become coal, bitumen (asphalt)

•Animal remains become oil & gas (petroleum, diesel) from which we make plastics, lipstick, varnish, etc, etc

•“Fossil Fuels” are super-concentrated in carbon (+ sulfur, mercury, etc, etc) & big problem when you burn them: their tremendous amount of emissions have changed our climate

Sedimentary structures

•Most common : bedding or layering as the sediment or chemical ppt. is accumulating on the ocean floor or on land

•Cross bedding: layers in various angles, formed in deserts

•Graded bedding: formed in slopes, larger stones at the bottom

•Ripple marks: formed by waves

•Mud cracks: in dried up areas, clay shrinks into 6-sided blocks

•Oolites: look like fish eggs, actually chemical precipitates on the ocean floor by movement of currents

Sedimentary Facies

•Environments of deposition

•Most sedimentary rocks form in shallow water (continental shelf) with the sediment or chemical transported there by rivers

•The bigger the fragments, the closer to the shore at the time: Sand size fragments accumulate close to the shore, clay-size further away from the shore

      

Mountains form :          Sedimentary rocks near top of mountains (see “lines” on

                                             slopes)

                                             Metamorphic rocks  at some depth

                                             Igneous rocks at great depth – after the rock melts

Metamorphic rocks

•“change in form”, alteration of an igneous/sedimentary rock due to a higher T/P environment, usually under a mountain

•Alteration in solid form (no melting)

•Changes in composition (minerals present)

                        texture (size of crystals)

                        structure (layered or not)

Metamorphic minerals”: only found in metamorphic rocks

•Talc

•Garnet – multi-color

•Graphite

•Asbestos

•Serpentine - green

•Chlorite - green

•Epidote – pistachio green

•Diamond (150 km depth)

•Ruby - red

•Lapis lazuli - blue

•Jade - green

Energy supplied by

•Higher temperature (from greater depth)

•Higher pressure (from greater depth)

•Heat from hydrothermal solutions

Result

•Denser minerals

•More compact rock (no pore spaces)

•Rock cleavage (slate for pool tables)

Classification

•Foliated (layered)

4 types according to T/P

Size of crystals increase

1.Slate (not visible)

2.Phyllite (sheen)

3.Schist (visible)

4.Gneiss Visible & segregated, striped rock

•Non-foliated (massive)

Marble : calcite/dolomite

Quartzite

Serpentinite - green

Amphibolite – dark green

Soapstone - green

Hornfels - green

Gneiss: is used to bake bread
it won’t crack, because it has not melted previously(probably)

Ancient marble theatre

Metamorphic facies

•Minerals are stable under certain T/P conditions

•Can tell T & P from the minerals present

•Can also tell depth inside the earth where rock formed

•Minerals are stable under certain T/P conditions

•Can tell T & P from the minerals present

•Can also tell depth inside the earth where rock formed

Rock Cycle

•Continuous recycling of rocks, their minerals,

•their metals and gases

•Cycle starts when rocks exposed to the surface

•Weathering breaks rock down

•Addition of water forms clays (example: feldspars turn into clays)

•Deposition & diagenesis forms sedimentary rocks

•Deeper burial

•Water loss as minerals change into other minerals (example: amphibole to pyroxene releasing water)

•Rock reorganizes under higher T, P & the presence of hydrothermal fluids and turns into metamorphic rock

•With deeper burial there is melting, magma forms and it will either cool in the interior (to form a pluton) or extrude as lava plus gases (water released)

Conclusions

•One type of rock can turn into a different type

•Any type of rock can be exposed to the surface and weathering will break it down. In this way, the rock cycle starts again

•The Sun drives the surface processes while the “Heat Within” powers the formation of metamorphic rocks and magma (which leads to the formation of igneous rocks)

HOW CAN YOU IDENTIFY THE 3 TYPES OF ROCKS ?

IGNEOUS                                 SEDIMENTARY                         METAMORPHIC

Bunch of crystals                   sediment or chemical             flattened rock

No layers                                 layers, some maybe thick       layered or massive

Only silicates                    around here mostly limestone    gneiss most common

Alfred Wegener, early 1900’s

Plate Tectonics

•World map available ~ 1,550 AD. He matched coastlines of Africa & S. America

•Alfred Wegener travelled the world to prove that continents used to fit together like pieces of a puzzle (Pangea was the supercontinent)

•Proposed the continents moved, but he did not know how (Continental Drift discovered around 1974)

Wegener’s evidence

•Coasts matched

•Rocks formations matched

•Fossils matched (examples: dinosaurs, plants)

•Mountain chains continue across continents

•Ice Age formations also continue across continents

•Present-day coast outlines match exactly if continental shelves are added around continents

New evidence

•Paleomagnetism : ancient magnetism preserved in rocks –magnetite crystals line up with magnetic field at the time they form

•Earth behaves like a bar magnet. Also, the polarity reverses once in a while

•Magnetic reversal pattern of successive lava flows on the ocean floor supports the seafloor spreading theory with identical patterns on both sides of the oceanic ridges

Electricity & magnetism go hand in hand

•An electric current will form a magnetic field around it

•Moving a magnet will create electricity

•On the globe : 30 % is Land                & 70% is water

            but 45 % is continents               & 55 % is ocean

                        (land + continental shelves)

Lithosphere (plate) : solid made up of crust + upper mantle & in constant, slow motion

Asthenosphere : plastic layer underneath the plate, where magma forms

Plate boundaries : 3 types

•Divergent (pull-apart, spreading ridges, rifts):

System of inter-connected fissures on  ocean floor & Iceland. East African Rift (Dead Sea to Mozambique)

   Transform (Sliding) : along faults. One side moves in opposite direction to other. Examples: San Andreas Fault, Anatolian Fault

•Convergent (colliding): 3 types

•1. ocean plate against ocean plate: result is subduction with trench forming. Melting produces magma than forms chains of volcanic islands: “island arcs” such as Japan, Philippines, Indonesia, Aleutians, Caribbean. These islands form arcs, because plates meet at oblique angles, not at right angles

•2. ocean plate against continental plate. Result is subduction under the continent. Magma forms volcanoes on land. Examples : Nazca collides with S. America and forms the Andes mountains, Cocos plate collides with Central America and forms volcanoes, while Juan de Fuca plate collides with N. America & forms the volcanoes of the Cascadia Mountain range

•3. two continental plates collide forming mountains. Examples : India collided with Asia to form the Himalayas & Africa collided with Europe to form the Alps & other mountains in southern Europe

Volcanic mounds & Hot Spots

•Hot spots are stationary. The plates move over them carrying the volcanic pile with them, much like pulling a carpet & everything on top of it. Example is Hawaiian islands. There is a continuous chain of volcanic mounds on the ocean floor extending to the NW as far as the Aleutian islands- the end of the Pacific plate. The further away from the hot spot, the older the volcanic pile is. In front of the Aleutian islands the oldest mound is 75 m.y. old. That is as old as the Hawaii hot spot.

Driving mechanism

•The heat trapped within the earth since its creation provides the energy to drive the plates.

•Heat moves upwards towards the surface by convection (compare to heating water in a pot)

•Relatively hot areas within the mantle (mantle plumes) have been outlined in the earth’s interior. Eventually, these plumes will create new rifts or hot spots in the crust.

Natural resources & plate tectonics

•The intrusion or extrusion of magma in the earth’s crust is responsible for mineral deposits, such as gold, silver, copper, zinc, nickel, etc. Therefore, such deposits are forming at the plate boundaries of today and have been found in former plate boundaries of the earth’s past.

•Example: the porphyry copper deposits of the American Cordillera, Central American mountains and the Andes mountains.

Plate Tectonics Theory

Explains

•Location of volcanoes

•Location of earthquakes

•Predicts future eruptions & earthquakes

•Predicts the discovery of new metal deposits

Shaking & waves

•“Earthquakes don’t kill people, buildings do”

•In earthquake areas, you have to make sure buildings are built acc. to regulations

Earthquakes

•Movements in the crust due to plate tectonics

•Energy for shaking the earth comes from stretching of rocks (like an elastic band, it becomes warm when stretched)

•Earth behaves like an elastic, can

1.Deform under stress

2.Strained rock stores energy. This energy is released in 2 ways: slowly by continuous movement of the rock (aseismic creep), or suddenly, rocks move past each other along a fault creating an earthquake

•Most of the energy is used to displace rocks.

•Some is released in the form of seismic waves

•Accumulated energy is tremendous, equivalent to many atomic bombs

•Place of movement is the focus or center with epicenter directly above- where most damage takes place. Deepest focus is 680 km, below that no movement due to high pressure

Seismic waves

•P (primary, compressional) in straight lines, all directions, like sound waves. Possible in solids, liquids & gases. Travel at ~ 5 km/sec

•S (secondary, shear) up & down. Only possible in solids. Slower than P

•P & S are body waves, travel through whole earth unlike the

•L (Love, first to describe them) travel along surface & do most of damage to buildings. Combination of P & S movement

Seismographic stations - see Lab. 6

•Instrument to record movement of ground

•A rotating drum anchored to ground with a writing device suspended with a spring so that it is not attached to the ground.

•Record of earthquake is the seismogram

•Time difference between P & S waves tells us how far the earthquake was (like lightning & thunder)

For your iPhone: get a warning

Make a seismometer in class!

•Time difference will not tell in which direction the earthquake was

•The distance to the earthquake can be plotted as a circle around the recording station

•Need to have 3 circles that intersect at 1 point to locate the source of the earthquake.

•~ 100 seismographic stations in Canada

Magnitude of an earthquake

•The max. up and down movement of the instrument would be proportional to the strength of the quake

•Use Richter scale. A logarithmic scale, each number is 10 X bigger than smaller number

•A magnitude 5 quake and higher will cause damage to buildings

•Highest recorded was 9.5 in Chile, 1960

Effects

•Ground shaking is the most common effect

•Less damage if building built on bedrock

•More shaking if built on sediment

•Worst if built on soil with water. Ground will behave like quicksand (liquefaction)

•Surface faulting on the surface will displace a road, fence, etc

•Landslides on slopes with unconsolidated material

•Tsunamis if quake below sea floor

•Waves of a very long amplitude, hardly noticeable in  the ocean, move very fast (1,000 km/h) & become very high  approaching the shore and sweep onto land destroying structures & trees on their way (when they hit land they keep moving uphill, that is how much energy they have)

“Earthquake wedding”: Sichuan,  China, 2008

Story of tsunamis

•1,650 BC: Minoan civilization (oldest in Europe) destroyed by tsunami on the island of Crete (the Crees left & prob. moved to N. America : they were the best marines then & now)

•Exodus of the Jews from Egypt: water retreats just before tsunami hits

•365 AD: Alexandria destroyed by tsunami that killed 50,000

•Last major in 1964 then, nothing until 2004

Videos/pictures of tsunamis they used to call it “tidal wave” !!

•Very rare

•Paintings of Alexandria tsunami & Atlantis tsunami exist

•1 picture of the 1946 tsunami in Hawaii & very short video

•1 video of tsunami in Siberia – only Russians knew about it

•Fake posters, fake movies to warn people did NOT work

•No big tsunami from 1964 (Crescent City) to 2004!

New wave of tsunamis

•Start in 2004 with a Bang!

•People tragically caught unaware

•Both Indonesians plus thousands of European / American tourists (supposed to be more “educated”, some Americans thought it was a terrorist attack !!!)

•Only 2 kids, 9 & 10 year olds (from England) seem to know what a tsunami is

•The 9 year old girl convinced hotel people to move to top floor, all of them saved!

2004 tsunamis

•Killed at least 250,000, maybe as high as 350,000

•No one really knows, because whole families/villages were wiped out

•Some affected areas were in a state of war with their country (Indonesia), so they didn’t care to help them!

Sumatra, 2004: lots of video, only 1 picture

Only picture

It is a natural phenomenon

When you feel tremor and you are near the sea:

•You run uphill

•Like all animals (who are smarter than people)

    including insects & birds

. The fish in the sea disappear (they go hiding, or trying to jump onto the land)

Sumatra, 2004: completely unprepared

Height of two of the waves

waves have already hit

Chile, 2010

Japan 2011 earthquake & tsunamis: lots of video, lots of pictures

The Japanese

•Are the only people in the world who are prepared for tsunamis

•Tsunami is a Japanese word meaning “harbor wave”

•Some towns have built walls along the shore for protection

•Have frequent evacuation drills

•Even they suffered because of inadequate warnings – about 14,000 died

Cascadia earthquake, 1700 AD with tsunami

Evidence of Cascadia tsunamis: “ghost forest” along the shore

Seismic belts

•75% of quakes around the Pacific ocean assoc. with subduction, trenches and volcanoes

•15 % along mountain belts of Europe & south Asia

•5% along the ocean rifts

•5% in other scattered areas

Earthquake prediction

•Small periodic tremors usually precede bigger quakes, but sometimes no warnings

•Radon gas seeps into groundwater prior to a quake

•Unusual animal behavior described previously  by ancient authors

-Mass migration of ants carrying their eggs

-Rats, snakes, weasels, centipedes, worms, beetles migrating out in numbers

-Locusts (grasshoppers) creeping through the streets towards the sea

-Eels crowded onto the beach in advance of a tsunami

-Bees flew from their hives out 2 min before & returned after the shock

-Hibernating snakes left their burrows & froze to death rather than return to the earth

-Appearance of bats during the day

VIDEOS ON EARTHQUAKES

Video :•India, San Andreas Fault, Mexico, Armenia, Tangshang, Tokyo

Video: Turkey & elsewhere

•Specialists in the rescue : remote cameras, listen for noise

•Dehydration of victims

•Northridge, 1994: 13 seconds, 72 died

•Alaska, 1964: 4.5 minutes! “end of the world”

•Mexico city, 1985: 22 “miracle babies”

•Japan: Earthquake capital of the world

Video: The 1985 Mexico City Earthquake

VIDEOS ON TSUNAMIS (some will be shown)

Video: Tsunamis (killer wave)

•Last century: 50,000 died

•Hilo, Hawaii in 1946 (hit from Alaska)

•Pacific Tsunami Warning Center from 1948

•Hilo hit again in 1960 (from Chile)

•Frequent disasters in Japan including Okushiri

•Walls, signs & evacuation drills

•Crescent City, Calif. In 1964 (from Alaska)

•New danger in Cascadia

•It was just a legend

•Ghost forest, sand layer from tsunami, land dropped from quake forms salt marsh

•People don’t trust tsunami warnings

Video: 5 years after the 2004 tsunami

•9.3 quake + 6 tsunamis

•Videos taken by tourists

•Banda Ache, Indonesia

•Malaysia : Phuket, Khao Lak, Phi Phi

•Sri Lanka

Video: Cascadia Tsunamis

•Expecting N. America’s biggest disaster (?)

•Evidence of past tsunamis

•“you can survive a tsunami if you know what to do”

•Computer modeling of previous tsunamis help prediction with great accuracy

•“people take tsunamis seriously now”

•Port Alberni “wave” of 1964

•Movement of mountains in B.C.

•Japan records gave exact date & time of the 1700 tsunami

•Bottom-sea sampling proved previous tsunamis (from sand layer in the soil)

•Research along San Andreas Fault

•Buildings reinforced in Vancouver

•Seaside, Oregon get prepared with town model

•B.C. hesitated to put warning signs up

•Prediction studies done for every town along ocean

•Vertical evacuation in strong buildings

•Many people still don’t get it (seriously)

•9-yr old girl saved all people in one hotel (2004)

Years between Cascadia tsunamis

•314 from last one    |    174

•174                             |    136

•106                             |    285

•269                             |    324

•228                             |    211

•184                             |    318

•173                             |    348

•298                             |    732, 754, 350, 462, …

Japan 2011 videos

•From You tube

•Coast Guard boat out at sea

•Tourist Liner almost capsizes

•Master boatman saves fishing boat

•Tsunamis hit

•Tall buildings swaying from 9.0 earthquake

Earth’s Interior

•Information obtained by studying seismic waves, drilling long holes (only a 12 km long in Russia) & studying meteorites which give clues from other parts of the solar system

•Seismic waves refract (bend) as they travel in the interior due to higher densities. P waves go right through (~ 20 minutes to cross the earth), while S waves can’t go through outer core (which is liquid)

•Continental crust is 35-100 km thick &

•Oceanic crust is only 5 – 8 km thick

•The Moho separates the crust from the mantle below

•The Gutenberg separates the mantle from the core at a depth of 2,900 km

•The center of the earth is 6,400 km away where the temp. is 4,500 ‘C with a pressure of 4 million atmospheres

•Crust is made up of igneous, sedimentary or metamorphic rocks (no meteorites are like that, because the earth’s crust is unique to earth - no meteorites like the crust have fallen!

•The mantle is made up of olivine + pyroxene. The stony meteorites are like the earth’s mantle

•The core is made up of iron plus some nickel and cobalt. So, it is like the iron meteorites

You know…

•What the planet is made up of

•How the earth “works”

•The heat within is the power that drives surface phenomena

•Earth does not punish people, but people have to learn how to respect nature

Fieldtrip May 21, 2015

May 2016

May 2017 class

Other courses offered:

First year : Historical Geology

Second year:  Environmental Geology

                       Continents Adrift

                      Earth's Mineral Resources

                     Geology of Meteorite Craters

                     Geomorphology