Transcript Law of Superposition

Warm Up
Match the type of evidence with what scientists
could learn about it.
Type of Evidence:
1)Tree rings
2) trace fossils
3) mold fossils
4) petrified wood
What can be learned:
A) ancient trees
B) shape of organisms
C) footprints
D) recent weather patterns
Homework : Vocab Set 3, Day 1
Vocab Set 3
When you are done, copy next vocab
1. Uniformitarianism
2. Geologic Time Scale
3. Evolution
4. Charles Darwin
5. Overproduction
6. Adaptation
7. Variation
8. Natural Selection
9. Isolation
10.Speciation
11.Independent Variable
12.Dependent Variable
13.Control
14.Qualitative
15.Quantitative
5.01 Interpret ways in which rocks, fossils, and ice
cores record Earth's geologic history and the
evolution of life including:
– Geologic Time Scale.
– Index Fossils.
– Law of Superposition.
– Unconformity.
– Evidence for climate change.
– Extinction of species.
– Catastrophic events.
Dating Rock Layers Notes
Relative Age: rock’s age when compared to the
ages of other rocks. Layers of rock that are
younger will be deposited on top of layers of
rocks that are older.
Index Fossil: a fossil that is widely distributed and
represents a type of organism that existed only
briefly
Law of Superposition: in horizontal
sedimentary rock layers, the oldest is on the
bottom and each higher layer is younger than
the layer underneath it
Stack three layers of clay (lightly), draw it into
the superposition area of your notes, label
youngest and oldest layer
Overturning: Horizontal rock layers tilt or fold
due to movement of tectonic plates.
Using the layers created previously, gently fold
your layers in half (like a taco). Draw it into
the overturning section of your notes. Label
the youngest and oldest layers.
oldest
middle
youngest
Unconformity: a gap in the geologic record showing
where some rock layers have been lost because of
weathering and erosion.
Mechanical weathering: wind, water examples
Chemical weathering: acid rain examples
Biological – tree roots
Carefully unfold your rock layers.
Gently remove the top layer.
“Erode” (remove) part of the middle layer
Replace the top layer
Draw this into the unconformity section of your notes.
Label the part of your diagram that is the unconformity.
Chemical weathering
(acid rain most common)
Mechanical Weathering
(wind, water, gravity, ice wedging)
Mechanical Weathering
(wind, water, gravity, ice wedging)
Biological Weathering
Unconformity
Fault: a break in earth’s crust. When examining
rock layers, the fault will have occurred after the
layers it cuts across and before the continuous
horizontal layers above it.
Fault: a break in earth’s crust. When examining
rock layers, the fault will have occurred after the
layers it cuts across and before the continuous
horizontal layers above it.
Happened:
Sixth
Fifth
Fourth
Third
Second
First
Intrusion: lava can cut/melt through rock layers. It
cools and hardens into igneous rock on the
surface. It is younger than the sedimentary
layers it cuts through and may be older than the
sedimentary layers above it.
Carefully layer the three clay colors again
Insert your pencil through the bottom two layers,
make sure you can see it
Draw the clay model into the intrusion/extrusion
section of your notes
Label the youngest and oldest layer, label the
intrusion.
Intrustion
Absolute Age: the number of years since rock
has formed. (IGNEOUS ROCK – “pure”)
Radioactive Dating: Gives the absolute age of
rock by using the unique half-life of an
element.
Half-Life: the length of time it takes for half the
atoms in a sample to change from one form to
another form. Radioactive elements with long
half-lives are better for determining the
absolute age of rocks.
You cannot use radioactive dating on
sedimentary rocks because……
THEY ARE MADE FROM BITS AND PIECES OF
OTHER ROCKS. (not “pure”…muts )
You can use radioactive dating from igneous
rocks/intrusions