Week 7
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Feb 20, 2024
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Week 7
Palaeontology and relative dating
(1) Which of the following would NOT be considered a fossil?
(a)
a dinosaur bone
(b)
a dinosaur footprint
(c)
the impression of a fern leaf
(d)
a basalt dyke
(2) In which of the following rocks would you be most likely to find fossils?
(a)
gneiss
(b)
limestone
(c)
granite
(d)
basalt
(3) What type of fossil is shown in the picture?
(a)
body fossil
(b)
trace fossil
(c)
permineralized fossil
(d)
cast fossil
(4) Why are feathers rarely found in the fossil record?
(a)
because birds usually die in dry environments
(b)
because feathers do not contain hard parts
(c)
because feathers are very small and thus are not well preserved
(d)
because birds die in forests, areas with high oxygen levels
(7) What type of fossil forms when a buried organism decays or is dissolved, but the original shape is preserved in the sediment?
(a)
body fossil
(b)
trace fossil
(c)
mould fossil
(d)
cast fossil
(8) Explain why the fossil record is incomplete.
The fossil record is incomplete due to biases in fossilization, where not all organisms have equal chances due to factors like hard tissues and environmental conditions. Additionally, destructive forces, limited geological exposure, biological rarity, incomplete preservation, fossil loss, sampling bias, and the challenge of recognizing gradual evolutionary transitions contribute to this incompleteness.
(9) What is a fossil? In what type(s) of rock are fossils most likely to be found? Why?
A fossil is the preserved remains or traces of once-living organisms, and they are most likely to be found in sedimentary rocks. Sedimentary rocks, formed through the accumulation of sediments, provide conditions conducive to fossil preservation, including the protection of soft tissues, burial of organisms, and the layering that preserves fossilized structures.
(10) If the relative ages of two formations are known, what else about them can be inferred?
(a)
their absolute ages
(b)
their fossil assemblages
(c)
their lithologies
(d)
their relative position in the geologic column
(11) Based on the figure below, what is the age of Layer 7 relative to Layer 3
(a)
Layer 7 is younger than Layer 3
(b)
Layer 7 is older than Layer 3
(c)
Layer 7 and Layer 3 are the same rock type, so they are the same age
(d)
Their relative ages cannot be determined
(12) Based on the figure above, which principle of stratigraphy could be used
to determine the relative ages of Layer 7 and Layer 3?
(a)
the principle of fossil succession
(b)
the principle of original horizontality
(c)
the principle of lateral continuity
(d)
the principle of inclusions
(13) Uniformitarianism is succinctly summarized by which phrase?
(a)
The future is the key to the present
(b)
The present is the key to the past
(c)
The past is the key to the present
(d)
The present is the key to the future
(14) As understood by modern geologists, the principle of uniformitarianism implies that
(a)
the Earth has always had the same basic appearance that it has today
(b)
igneous, metamorphic, and sedimentary rocks are uniformly mixed throughout the crust
(c)
physical processes observed today (such as erosion and volcanic eruptions) have been active in the past at roughly the same rates
(d)
physical processes observed today (such as erosion and volcanic eruption) occurred much more rapidly in the past, quickly sculpting the Earth’s surface
(15) In the area immediately surrounding an igneous intrusion, a host limestone is locally metamorphosed to produce marble. Which of the following statements is correct?
(a)
The intrusive igneous rock must be older than the limestone
(b)
The limestone must be older than the marble
(c)
The limestone must be younger than the marble
(d)
The relative ages of the three units cannot be determined with the information given
(16) In an undisturbed sequence of sedimentary rocks, younger layers overlie older layers, according to the principle of
(a)
superposition
(b)
original continuity
(c)
original horizontality
(d)
uniformitarianism
(17) If a basalt dyke cuts across a fault, what are the relative ages of the basalt and the fault?
(a)
The fault must be older, according to the principle of cross-cutting relationships
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(b)
The basalt must be older, according to the principle of cross-cutting relationships.
(c)
The basalt must be older, according to the principle of original horizontality
(d)
Their relative ages cannot be determined from the information given
(18) Which of the following statements is true regarding the clasts (labeled 5) inside the granite pluton?
(a)
The inclusions are the same age as the pluton
(b)
The inclusions are younger than the pluton
(c)
The inclusions are older than the pluton
(d)
The relative age of the inclusions and the pluton cannot be determined
(19) Look at the figure below. The contact between the Unkar Group and the Tapeats Sandstone is a(n)
(a)
conformable contact
(b)
disconformity
(c)
nonconformity
(
d)
angular unconformity
(20)
The photograph below illustrates three relative dating principles. List three relative dating principles and explain how they are visible in the photograph.
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Principle of Superposition:
Description: In an undisturbed sequence of sedimentary rocks, the youngest rocks are at the top, and the oldest rocks are at the bottom.
Principle of Original Horizontality:
Description: Sediments are deposited in horizontal or nearly horizontal layers.
Principle of Unconformities:
Description: Gaps in the geologic record created by erosion or non-deposition, indicating periods of
missing time.
(21)
The outcrop photograph below shows two different
rocks. Indicate on the photo the oldest and the
youngest rock. Which geological principal did you
apply?
The mafic rocks are younger as they didn’t have time to form
crystals so they would have just formed around the original
rock (23) The dark rock in the photo below is a sill that has intruded between older sedimentary rock layers. What is the evidence for this? Page 4
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The evidence for the sill intrusion includes a parallel orientation to the sedimentary bedding, concordant contacts, distinctive mineralogy, smooth contacts, and potential columnar jointing.
(32) Which of the following lists the divisions on the geologic column from largest (most general) to smallest (most specific)? (a)
epoch, period, era, eon
(b)
period, epoch, eon, era
(c)
era, eon, epoch, period
(d)
eon, era, period, epoch
(33)
Use the Geological timescale below to answer the following questions:
(a)
during what era did the dinosaurs diversify and become dominant,
Dinosaurs diversified and became dominant during the Mesozoic Era.
(b) what is the age range of the era when Dinosaurs became dominant?
The Mesozoic Era spans from approximately 252 to 66 million years ago.
(c)
when did the Late Proterozoic finish, in millions of years (Ma)?
The Late Proterozoic finished around 541 million years ago.
(d)
when did the Late Proterozoic finish, in billions of years (Ga)?
The Late Proterozoic finished around 0.541 billion years ago.
(e)
If the earth is 4.2 Ga in age, how many billions of years until the end of the Proterozoic?
If the Earth is 4.2 billion years old, there were approximately 3.659 billion years until the end of the
Proterozoic.
(f)
If the earth is 4.2 Ga in age, how many millions of years until the end of the Proterozoic?
If the Earth is 4.2 billion years old, there were approximately 541 million years until the end of the
Proterozoic
(g)
What is the name of the Period when the dinosaurs diversified?
The period when dinosaurs diversified is the Triassic Period, which is the first period of the Mesozoic Era.
(34)
(a)
When did the Dinosaurs disappear and what was the cause?
Dinosaurs disappeared around 66 million years ago, and the cause is widely attributed to a combination of Page 5
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a large asteroid impact and volcanic activity, leading to environmental changes and mass extinction.
(b)
When did the “Cambrian explosion” occur?
The "Cambrian explosion" occurred approximately 541 million years ago.
(c)
What is the “Cambrian Explosion”?
he "Cambrian Explosion" refers to a rapid diversification of multicellular life forms that occurred during the Cambrian Period. This event marked a significant increase in the variety and complexity of life, with the appearance of various animal phyla.
(d)
What is “Snowball Earth”?
"Snowball Earth" is a hypothesis suggesting that Earth experienced periods of extreme glaciation, possibly covering the entire planet in ice. This hypothesis proposes that during certain intervals in Earth's history, the planet's surface was largely or entirely frozen.
Week 9
Surface processes
(1)
Which of the following is NOT a type of chemical weathering?
(a)
oxidation
(b)
salt wedging
(c)
Hydrolysis
(d)
Dissolution
(2)
Which of the following are NOT considered sediments?
(a)
fragments of shells
(b)
fragments of rock
(c)
cemented grains
(d)
precipitated crystals
(
3)
Which of the following is a type of physical weathering?
(a)
thermal expansion
(b)
dissolution
(c)
oxidation
(d)
hydration
(4) Sediment formation is the result of __________ at the Earth’s surface
(a)
Igneous activity
(b)
metamorphic activity
(c)
weathering
(d)
hydration
(5) Lahars occur on ________.
(a)
volcanic slopes
(b)
vertical cliff faces
(c)
undersea slopes
(d)
divergent plate boundaries
(6)
What does the acronym CLORPT refer to, and how does it encapsulate the major factors of weathering?
C:
Climate affects the type and rate of weathering processes.
L:
Organisms, including plants, contribute to both physical and chemical weathering.
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