Transcript Understanding What We See

Earth History
From the Rocks
Understanding What We See
As most people drive they ignore road cuts.
Road cuts give us a window into the history
of the the area.
The layers of Sedimentary Rock created by
Weathering, Erosion, Deposition and
Lithification can tell us what conditions were
like in the area when the rock was created.
Understanding What We See
Image an ordinary hill with layers of
Limestone, Shale and Sandstone.
Understanding What We See
Using the Law of Superposition Which layer is oldest? Youngest?
Understanding What We See
How did the Limestone form?
The Shale? The Sandstone?
Understanding What We See
What if the hill looks like this?
Understanding What We See
If we found a fossil in layer III. Then
miles away we found the same fossil in
another layer. What could we infer
about the two layers?
Understanding What We See
Which layer is the oldest? Why?
Which is the youngest? Why?
Understanding What We See
What could cause layer III to be older
than layer V?
Understanding What We See
Why do we have tilted rocks like layers
A-F?
How could that happen?
Understanding What We See
Which layer is older A or D? Why?
Which layer is older F or K? Why?
Understanding What We See
What is represented by the dark line
below layer H?
Understanding What We See
Are layers K & H the same?
Why aren’t they aligned?
Understanding What We See
Which happen first, Layers I & J or the
Fault between E & D?
Question 1
If you understand how sedimentary rocks
form you can?
a.
b.
c.
d.
Infer the history of the area.
Place events in relative order.
Describe how live has evolved.
All of these.
The Law of Superposition says?
a.
b.
c.
d.
Rocks can predict the future.
Rocks can tell you what the area was like.
The bottom is the oldest layer.
How old the fossils are?
Question 3
An Index Fossil can tell you?
a.
b.
c.
d.
The age of the rock layer.
What the place was like.
The new of the old ecosystem.
Why the species went extinct.
Question 4
An unconformity is?
a.
b.
c.
d.
A
A
A
A
layer of sedimentary limestone.
layer of a specific age.
layer with Index fossils.
missing layer(s) that eroded.
Question 5
Siccar Point is/was?
a.
b.
c.
d.
Told
Told
Told
Told
Hutton
Hutton
Hutton
Hutton
how Volcanoes work.
the Earth was old.
about an Index Fossil.
how Sedimentary rocks form.
Question 6
An exception to the Law of Superposition
happens when?
a. A normal fault in under tension stress.
b. When a reverse fault is under tension
stress.
c. When a strike/slip fault moves sideways.
d. When a thust fault has compression
stress.
Understanding What We See
Stratigraphy – the study of rock layers.
To help understand the order of events
a diagram is often used called a
Stratigraphic Column.
Understanding What We See
Uncomformity – is a missing layer(s) of
rock in a Stratigraphic Column. Usually
caused by erosion at the surface.
Understanding What We See
Understanding What We See
Understanding What We See
Volcanic Intrusions – happen when
magma forces it’s way into layer of
Sedimentary Rock.
Earth History
From the Rocks