Review of videos you watched in class
Assume you work for the local newspaper and PBS showed you the first episodes of the documentaries (that you
watched in class) as preview to what they are going to show for their fall program. Write a brief review of 400 –
600 words, as you would write a newspaper column highlighting how effective the videos are explaining the
geological forces that have shaped this earth, how effective they are in
1) explaining and providing evidence for the age of the earth which is at least 4.6 BYA and
2) how nothing has been stable when measured in geological time including the location of continents and
climate.
Also discuss, how watching these videos give a perspective on the current human induced climate change and why
this is cause for concern even though when measured in geological time climate has been always been changing.
You could also include a note whether you liked one video better than the other or if both complemented each other
in explaining the concepts.
I have provided a summary of the major points discussed in the videos below.
They are also in the review sheet for Exam I
Video – BBC Earth Story – Two episodes – Episode 1: time Travelers and Episode 2: The Deep
(Narrated by Aubrey Manning)
– What is the significance of sedimentary layers in rocks?
– -Why is the age of the earth estimated from meteorites?
– -Why is there a difference of 500 MY between the rocks on earth and meteorites?
– -Destruction and formation of the earth’s crust
– – What did Hutton see at the exposed rock cliff in Scotland?
– -rocks – Igneous, Metamorphic, and sedimentary types
– – Which one is used to estimate dates?
– – different rock layers contain different assemblages of fossils. This is used to estimate relative ages of fossils.
– – index fossils
– – What does the shiny pyrite reveal in the rock beds at 6000m below the surface?
– Absence of free atmospheric oxygen when the earth was first formed.
– – What does the presence of crystals in 3.5 BY old rocks in Barberton in south Africa Reveal? Water
– – What do the globules trapped between rock layers suggest? Volcanic activity.
– – Presence of bacterial fossils in the rocks at Barberton.
– What is the significance of the rift valley along the continental crust in the oceans?
– How thick is the ocean floor compared to the thickness of the continents?
– How was the reversal of the magnetic fields used to explain continental drift? Magnetism and plate tectonics
support Wegener’s idea
– What hypothesis was tested to show the validity of continental movement?
– What kinds of organisms are the primary producers that live around hydrothermal vents in the bottom of the
oceans? How do these organisms obtain energy to make the macromolecules necessary for life?
Video – BBC- The Power of the Planet – Episode 1: Volcanoes (Narrated By Iain Stewart)
Stewart climbs to Erta Ale which has a permanent lake of molten lava in the Afar Region to show what process?
This compares to what other process?
The process of lava welling up, forming a crust, and then sinking affects the entire planet. The history of Earth has
been driven by the molten core which is as hot as the sun and fuels volcanoes.
In Iceland, molten rock heats the water. Stewart describes how Surtsey formed in the same manner as Iceland.
The Almannagja Fault in Iceland. Stewart scuba dives in the chasm to show the North American plate and between
it and the European plate, to explain plate tectonics and how hot rock rises when magma erupts, moving plates apart.
These continents move three-quarters of an inch annually and Stewart describes how Pangaea broke apart into seven
distinct lands.
He then explains how Mountain Form over time and how the Pacific and Australian plates collide, forming New
Zealand and the Southern Alps. Other ranges including the Andes, Himalayas, and the European Alps also form
similarly and shows an event in Northern Pakistan, Muzaffarabad how an earthquake that was measured before and
after the event saw the land rise by several inches. This process repeated again and again is what causes mountains
to rise over time – measured in millions of years to account for the Himalayas.
He then illustrates how if wasn’t for these geological events that build mountains water in the form of rain and in
rivers would erode all land and carry silt to the oceans. This earth will become flat if the plates stop moving.
How does Stewart use volcanoes to explain key roles in providing the raw materials for origin of life and also to
recycle carbon captured by photosynthesis back into the atmosphere.
What was the role of volcanoes in ending the snowball earth era (When did this happen?) and what effect did it have
in the evolution of life? What role do volcanoes play in climate measured in geological time and how does it
compare with current human induced climate change?