Why did Hutton believe earth was older than 6000 years?
He saw really old rocks that had cross cutting relationships.
One layer is up lifted and the next layer is laid across that one.
When the earth was first formed the surface was molten.
Kelvin believed that planet was completely molten and was at least 20 million years
old.
Radioactivity inside our earth is continually heating the inside of our planet.
Radioactive dating turns to lead at a steady rate.
We think earth is 4. 5 billion years old.
Collisions of many hot meteors pitted the earth’s surface.
How do we know the planet was covered with water 1 billion year ago?
Pillow lavas were formed, they can only be formed under water.
Why did all the water that was inside the earth boil away?
Where else could water have come from?
How did carbon dioxide in the atmosphere help to trap the rainfall?
The first rainstorm lasted 1 million years
When did land emerge?
Why was the water filled with iron? The rain and the water in the ocean dissolved
the iron in the ocean water
Why was the air pressure so much more than it is now? The atmosphere was made
up of a heavier gas that is carbon dioxide
Granite is lighter (less dense) than basalt.
After 1 billion years granite began to form and became land.
Super heated basalt coming out of rifts filled cool ocean water made the conditions
that made granite.
Granite does not erode easily, so the land was able to remain against the ocean
currents and waves.
Shallow coastline waters were very important for the development of life.
Stromatolites were the first single celled organisms and produced a lot of oxygen.
They lived off the of the energy of sunlight.
Fossilized stromatolites that are 3.5 billion years old have been found.
Thin layers of algae like organisms and then the waste products are like rocks. That
is why they have such a strong fossil record.
Stromatolites made CO2 into O2. As the oxygen became more concentrated in the
ocean the iron was turned into iron oxide and the ocean turned from green to blue.
Plate tectonics is the study of the movement of land masses.
We first became true believers of plate tectonics in the 1960’s
It was first proposed by Wegener in 1912 as an explanation for the distribution of
fossils.
Fresh water paradoxidies is a fossil that was found on both sides of the ocean.
Mapping the ocean to make good maps by the US Navy for submarines helped us to
see all the rifts on the ocean floor.
Recycling of the ocean floor. Mantle currents cause pieces of oceanic crust to be
dragged back into the inside of the earth and melted.
Fissure eruptions are evidence of divergent plate boundaries. They can result in
curtains of lava flying up in the air for 50 feet.
Iceland is important to the study of plate tectonics.
Fossils and types of ancient rocks and minerals can be matched up on each side of
each rift or continental margin.
When did the land masses draw together to form a super contininent Rhodinia? 1
billion years ago.
Rhodinia was like Mars. Why were there no plants no forest no grasslands? Are we
likely to change Mars to good land? Why or why not?
There was a giant ice age when ocean currents were changed 650 million years ago.
It lasted for at least 50 million years and as it blocked the currents in the ocean the
entire planet was covered by ice and the ocean was entirely covered by a mile of ice.
The whole planet would have died by as the temperature was 40 degrees below
zero .
Beneath the ice the super continent was causing rifts that was breaking Rhodina
apart. The blanket of ice caused the heat from the inside of the earth had no where
to go; the air became filled with co2 and the planet warmed up. It caused the planet
to thaw. As the light reached the waters the land became habitable and the
Cambrian explosion occurred. Animals. Plants thrived because there was a diversity
of habitats, fresh water, salt water, warm and cold, differing soils and reproductive
populations were separated as the continents moved apart.
Complex organisms began to form, This was the time of the highest diversity.
100 million years oxygen was thick enough to form the ozone layer and theur the
ultraviolet light was thick enough that animals and plants could habitate the land.
400 million years ago the to 300 million years ago life covers the land. Tropical
swamps covered the land and resulted in the coals and the oils we are using today.
60 million years of swamps resulted in clas beds on all land masses.
When freshwater swamps rot the seal of the dry plant mass on the top prevents the
under layers from rotting and it turns directly to coal.
Oil is the rotting plants trapped in rock layers.
The industrial revolution is the direct result of the oil and coal trapped back then.
Two foot dragon flies.
Enormous volcanic eruptions would cause a mass extinction. 250 million years ago.
Mantle plume under Siberia plumes of hot mantle surged to the surface of the earth
95 % of the species on earth were driven to extinction.
Pangea super continent emerged. Following this time was the age of the dinosaurs.
Terrible lizard aka dinosaur.
Dinosaurs were cold blooded or luke warm blooded . Active all year long all energy
went tino growing none into keeping war,
Volcanoes 180 million years moved the continents to their current positions
Tropical rain forests were key in their development because all the of the nutrients
were up in the vegetation.
150 million years ago. End of age of dinosaurs. Two causes of their demise.
Overactive volcanoes and
The volcanoes in western India gave aoff 600 feet of ash depth.
The rift pressures that broke aprt the continents was strong enough to give us
diamonds. The diamond bering minerals blew out of the earth in tremendous
pressures.
Powdery rocks layer that is covering the entire earth is made of a thin layer of clay
called the tombstone layer, it has a high concentration of iridium found by Luis and
Walter Alvarez. This was how they discovered that the matter must have been
caused by a meteor that landed 65 million years ago.
50 million years ago began the age of dinosaurs.
Alps are the result of the collision of two continents the African and the European
continent. Quartz crystals that are very small. The crystals are very deformed by the
pressures exerted on them. The Matterhorn is rock of African origin
The only thing that limits the heights of the mountains is the erosion by water. The
grand canyon is 1 mile deep and is the result of water carrying away the dirt and
rocks to leave behind the river bed below.
2 million years ago ancestors of modern humans were on the planet and there was
an ice age. Glaciers has covered the continents the evidence is in boulders and
gravel piles that have been left behind.
We are in a gap between ice ages….we have experience 10,000 years of stable
weather,