Planetary Science Lab #3/4 Earth's History/Rock Dating

Rocks and fossils are the primary tools geologists use to study the Earth's history. What is each best used for?

Rocks: numerical ages of geologic events, previous tectonic configurations

Fossils: evolution, extinction events

When did the first true dinosaur evolve?

end of the Triassic Period

Part 1: Life on Earth underwent huge diversification in the early Paleozoic; numerous types of organisms developed in water and on land. This event is called the __________.

Part 2: What two changes needed to happen in the atmosphere to allow life to move onto land?

Part 3: Prior to the widespread appearance of land plants in the middle Paleozoic, what did the land surface look like?

Part 1: Cambrian Explosion

Part 2: Oxygen and ozone had to become available in the atmosphere, The ozone layer in the atmosphere formed to protect the surface from UV radiation

Part 3: The land surface remained a stark landscape of rock and sediment, subject to rapid erosion

Part 1: What was Rodinia?

Part 2: When did Rodinia exist?

Part 3: Use the map of Rodinia below to answer the following question. Is the crust that would become North America in the same position relative to Antarctica as it was to Pangaea's assembly of plates?

Part 1: a supercontinent

Part 2: 1 Ga to 700 Ma

Part 3: no

The Paleozoic Era ended with a mass extinction event that was likely caused by

intense volcanic activity.

There is very little rock record for the Earth's first 600 million years because

intense meteorite bombardment may have destroyed most land surface.

Identify the appropriate time period when vascular plants with woody tissues, seeds, and veins shared the land with spiders, scorpions, insects, and crustaceans, while jawed fish cruised the oceans and the first amphibians left water to visit land.

middle Paleozoic

Which of the following was a component of the Earth's Hadean atmosphere?

ammonia

The first life forms

may have been simple cells of bacteria or archaea living near hydrothermal vents.

Place the following ages in order from oldest to youngest.

1: age of the Earth

2: age of the Moon

3: age of the oldest minerals on Earth

4: age of the oldest rocks on Earth

The first feathered birds appeared in the

Jurassic

Rodinia, Pannotia, and Pangaea are all names of

supercontinents

Solar storms, like the one in the video, may have caused a dramatic increase in nitrous oxide in Earth's early atmosphere, allowing it to warm enough to support life. What is the earliest life form found in the fossil record?

cyanobacteria

Theoretically, "snowball Earth" conditions of the late Proterozoic Eon would have persisted forever, were it not for greenhouse warming caused by

carbon dioxide

Which geologic time interval saw the first continents, the first life, and possibly the first plates?

Archean

The Earth's surface slowly changes due to plate tectonics. Each of the maps below represents a specific time in Earth's history. Drag and drop the three labels to the appropriate targets on the maps.

A (young Atlantic Ocean) top middle, C (Pangaea) bottom left, B (present day) bottom right

Rank the order of occurrences during the first 2 billion years of the Earth's history.

1: earliest evidence of liquid water

2: oldest rock sample

3: first chemical signature of life

4: first cratons

5: oldest undisputed fossils

During the Pleistocene Ice Age,

the continental shelf west of Alaska was exposed and allowed migration of animals and people from Asia to North America.

How did the Cambrian explosion of life change the nature of the living world?

Many defensive structures and behaviors were favored in natural selection due to the proliferation of carnivores, Numerous filter feeders and deposit feeders and large, mobile predators complicated the world food web

The Great Oxygenation Event, which added abundant oxygen to the atmosphere beginning about 2.4 Ga, was due to the

evolution of photosynthetic organisms in oceans.

Geologists believe that the impact of a 13-km-wide meteorite 65 million years ago

generated a hot-air blast and blaze that caused worldwide forest fires.

Which of the following statements is true?

Fossils of modern humans (Homo sapiens) date back about 200,000 years.

Which of the following refers to fossils of early multicellular invertebrates that are 565 Ma to 620 Ma, like the one shown in the photo?

Ediacaran fauna

Which of the following does not provide evidence for the great oxygenation event?

zircon deposits mixed with quartz

Identify the true statement.

There was intense meteorite bombardment of the Earth about 4 Ga that destroyed the Earth's earliest crustal rock.

In this relative age dating interactivity, order the geologic events chronologically from oldest to youngest, with the oldest being labeled "1st" and the youngest being labeled "4th."

From left to right: A, D, C, B

Is knowledge of evolution necessary to reconstruct a stratigraphic reference section using the principal of fossil succession?

No, fossil succession is a pure geometric and logical exercise. Knowledge of evolutionary relationships is not necessary to reconstruct the stratigraphic reference section.

Isotopic dating of rocks can provide you with information about which of the following?

when a rock was uplifted toward the surface, when a rock was metamorphosed, when magma cooled to form an igneous rock

Given the relationships shown in the block, what is the relative age of the features labeled, from oldest to youngest?

1: sedimentary rock

2: pluton

3: fault

4: dike

Order the steps in the formation of an angular unconformity.

1: Sediments are deposited and lithified

2: Regional mountain building takes place, and sedimentary layers are folded into anticlines and synclines

3: Erosion takes place

4: Sediments are deposited on top of an erosional surface

Select the statement that best describes the concept of fossil succession.

There is a definite relative order in which each fossil species occurs within the layers of rock on Earth.

This outcrop of Precambrian and Paleozoic rocks in northern Cape Breton, Nova Scotia, provides a great example of the kinds of relative age relationships that geologists observe in the field. Put the features in order from oldest (bottom) to youngest (top). The rocks have not been overturned.

1: Fault

2: conglomerate

3: mafic intrusion

4: felsic crystalline rocks

In this relative age dating interactivity, order the geologic events chronologically from oldest to youngest, with the oldest being labeled "1st" and the youngest being labeled "4th."

bottom to top: A, B, C,D

Select statements true of unconformities.

Unconformities represent periods of erosion in the rock record, Unconformities represent periods of nondeposition in the rock record, There are three major types of unconformities

A number of geologic principles allow geologists to observe the relative ages of rocks. Which of these images illustrates the principle of inclusions?

Image B, C

The image shows an outcrop of granite and basalt with a pink area between them that records contact metamorphism. Use the concepts of inclusions and baked contacts to select which of the following statements best describes the relative age relationship between the granite and basalt.

The granite is older than the basalt.

Which form of geologic dating is best used to identify when each rock type formed?

Numerical Dating: igneous, metamorphic

Relative Dating: sedimentary

Order the steps in the formation of a nonconformity.

1: Sedimentary layers are deposited and lithified

2: A granitic pluton intrudes sedimentary rock layers

3: Erosion takes place, exposing the pluton at the surface

4: Sedimentary deposition occurs again, covering the erosional surface

Classify the prominent unconformity shown in this illustration.

angular unconformity

Which of the following is a method used to determine numerical age?

counting ice bands in a glacier

Before the development of isotopic dating methods, scientists estimated the age of the Earth by

comparing rates of change on the Earth's surface today with the geologic record.

The diagram depicts the distribution of rock units and structures in a given location. Indicate the type of unconformity shown and the type of underlying geologic structure by labeling the image.

B (disconformity) far left, A (angular unconformity) top right, C (syncline) bottom

Which statements are true about William Smith's discoveries?

Using fossils, the relative order in which different rock layers were deposited is discernable, Not all fossil species are present in all locations, The relative vertical order of fossils is the same in all outcrops

Order the steps in the formation of a disconformity.

1: Sediments were deposited in a marine environment

2: Sea level fell, exposing marine deposits subaerially

3: Erosion took place

4: Sea level rose, covering the erosional surface, which was buried by marine sediments

Unconformities develop when new sedimentary layers accumulate atop old, eroded layers, resulting in a geologic hiatus.

Illustration B

The image shows geological changes that occurred at different times. Identify the geologic features by placing the labels on the appropriate targets.

B (sedimentary rocks) top left, A (baked contact) top middle, E (normal fault) bottom left, C (dike), bottom middle, D (pluton) bottom right

Which bed (labeled 1 through 10 on the image) does this limestone correlate to?

Bed 6

Place the units shown in the diagram into their order of occurrence by dragging labels into the correct position in the ranking (youngest at the top; oldest at the bottom).

1: Bed E

2: Dike H

3: Batholith G

4: Fault F

5: Bed A