Starr-Aisa Hayes
Intro to Physical Geology
1.
The white granite of the Idaho Batholith near Boise, ID contains dark gray xenoliths
of metamorphic material. Which is older? How do you know?
The xenoliths are older; you know this because of the principle of inclusions.
2.
The Mississippi River cuts through Silurian-aged dolomite between northwestern
Illinois and eastern Iowa. Which is older? How do you know?
The
dolomite is older and you know this because of the principle of cross-cutting relationships.
3.
What is the difference between an index fossil and a fossil assemblage?
Index fossil is far and wide and related with a somewhat restricted stretch of time and fossil
assemblage is the covering scopes of fossils in an assemblage might be utilized to lay out an age
for a rock layer that contains different fossils
4.
You are studying an outcrop where the base layer is limestone and the layer directly
on top of that is sandstone. Near the base of the sandstone are small, weathered
pieces of limestone entirely contained within the sandstone. Explain how these pieces
of limestone came to be contained within the sandstone.
This is possible because the Limestone was formed first and then the layer of Sandstone above it
formed after. Then through inclusion, sandstone formed around parts of the Limestone towards
the bottom of the sandstone layer.
5.
Assuming that humans went extinct today, do you think that humans would be good
index fossils? Why or why not? (List three reasons.)
It is improbable that humans would be helpful as to list fossils later on, as the time span during
which people have existed on Earth is somewhat short contrasted with the age of the Earth
overall. Furthermore, people are not small, broadly appropriated creatures like a significant
number of the regularly utilized file fossils. Instead, humans are large, highly adapted organisms
that have a wide range of habitats and are found on most of the continents.
