1.4 C: Geology = the Changing Earth 1.4 Getting a Handle on Time Flashcards
Who was William Smith and what was his significance?
William Smith (1769-1839) was a geologist known for mapping sedimentary rock layers in England.
What are catastrophist theories?
Catastrophist theories are explanations that attribute past changes in the Earth to violent events such as earthquakes, volcanic eruptions, and floods.
What did William Smith propose about sedimentary rock layers?
Smith proposed that the sedimentary rock layers he mapped were deposited by a series of catastrophic floods.
What types of events are considered in catastrophist theories?
Events such as earthquakes, volcanic eruptions, enormous floods, meteorite impacts, and upheavals of Earth’s crust.
In what centuries were catastrophist theories particularly influential?
The eighteenth and nineteenth centuries.
Fill in the blank: Catastrophist theories involve processes of a different type or intensity than those observed in the _______.
present.
True or False: Catastrophist theories suggest that past geological changes were gradual and uniform.
False.
What is uniformitarianism?
The principle that the geological processes in action today have always fundamentally operated in the same way throughout Earth’s history
This concept is often summarized by the phrase ‘the present is the key to the past.’
Define unconformity.
A surface in a rock sequence that represents a break in the pattern due to erosion or a lack of deposition
Unconformities can indicate significant geological time gaps.
What is uniformitarianism?
The principle that the geological processes in action today have always fundamentally operated in the same way throughout Earth’s history
This concept is often summarized by the phrase ‘the present is the key to the past.’
Define unconformity.
A surface in a rock sequence that represents a break in the pattern due to erosion or a lack of deposition
Unconformities can indicate significant geological time gaps.
What is sedimentary rock composed of?
Eroded fragments of other rock
Sedimentary rock forms from the accumulation and compression of these fragments.
How are sedimentary rocks formed?
From layers of sediment under relatively low temperatures
Sedimentary rocks form at the surface of Earth.
What is the origin of igneous rock?
Formed when molten magma intrudes into the crust or extrudes onto the surface
Igneous rock can form from magma that cools either underground or above ground.
What conditions lead to the formation of metamorphic rock?
Intense pressure and heat
Metamorphic rock is formed from sedimentary or igneous rock transformed at the molecular level.
Where are igneous rocks typically formed?
Deep within Earth’s crust and mantle under extreme heat
The entire mantle is composed of igneous rock.
What geological processes are associated with the formation of metamorphic rocks?
Collisions between crustal plates
Metamorphic rocks can form at tectonic plate boundaries where pressure and heat are significant.
What is the process called that describes the continual change of rocks from one type to another?
rock cycle
The rock cycle includes various processes such as weathering, erosion, and deposition.
What are the three main types of rocks involved in the rock cycle?
- igneous rocks
- sedimentary rocks
- metamorphic rocks
Each rock type undergoes transformation through various geological processes.
According to Hutton, where do all rocks start their formation?
molten magma within Earth’s mantle
This magma cools and solidifies to form igneous rocks.
What happens to igneous rocks after they form?
They weather and erode
Weathering and erosion are caused by elements such as water and wind.
Fill in the blank: The process by which sediments are laid down is called _______.
deposition
Deposition is a key process in forming sedimentary rocks.
What are sediments typically formed from?
weathered and eroded rock materials
Sediments can also include organic materials and minerals.
True or False: Metamorphic rocks can form from sedimentary rocks.
True
Metamorphic rocks are formed under heat and pressure from existing rock types.
What is the role of magma in the rock cycle?
Magma cools and solidifies to form igneous rock
The cooling process is essential for the formation of the first rock type.
What are the processes involved in the rock cycle? List at least three.
- weathering
- erosion
- transportation
These processes contribute to the transformation of rocks through the cycle.
What is the process called by which rocks change?
The rock cycle
The rock cycle describes the continuous transformation of rocks from one type to another.
According to Hutton, where do all rocks start out?
Molten magma within Earth’s mantle
Hutton’s theory emphasizes the origin of rocks from molten material.
What type of rock forms when magma cools and solidifies?
Igneous rock
Igneous rocks are formed from the cooling of magma or lava.
What processes weather and erode rock on the surface?
Water, wind, and ice
These natural elements contribute to the breakdown of rocks into sediments.
What do sediments eventually form?
Sedimentary rock
Sedimentary rocks are created from the accumulation and compaction of sediments.
What can sedimentary and igneous rocks be transformed into?
Metamorphic rocks
Metamorphic rocks are formed under extreme heat and pressure.
What ultimately happens to all rocks in the rock cycle?
They melt and return to the mantle
This melting is part of the continuous cycle of rock transformation.
What drives the rock cycle?
Energy released by nuclear reactions in Earth’s core
The heat generated from the core facilitates the processes involved in the rock cycle.
True or False: The rock cycle is a perpetual, balanced cycle.
True
The rock cycle is ongoing and maintains a balance in rock transformation.
Who is credited with bringing Hutton’s theory of uniformitarianism to the forefront?
Charles Lyell
Lyell was a geologist who expanded on Hutton’s ideas and made them more accessible.
What is the primary theory that Hutton proposed?
Uniformitarianism
This theory suggests that geological processes have remained consistent over time.
What methods did Lyell use to build the Geological Time Scale?
Index fossils
Index fossils are used to identify and date the layers of sedimentary rock.
What processes did Lyell argue have operated in fundamentally the same manner throughout Earth’s history?
- Erosion
- Sediment deposition
- Volcanic action
- Earthquakes
These processes contribute to the understanding of geological changes over time.
True or False: Hutton’s theories gained immediate acceptance in the scientific community.
False
Hutton’s theories were initially difficult to understand and were not widely accepted.
What was a significant challenge in Hutton’s original presentation of his theories?
Buried in a 2000-page book filled with difficult language
This complexity hindered the acceptance and understanding of his ideas.
How did Lyell’s writing style contribute to the acceptance of uniformitarianism?
He used a much more readable style
Lyell’s clarity helped communicate complex geological concepts effectively.
Who was influenced by Lyell’s methods and writing style?
Charles Darwin
Darwin’s work in natural selection was shaped by the geological principles established by Lyell.
Who is credited with bringing Hutton’s theory of uniformitarianism to the forefront?
Charles Lyell
Lyell was a geologist who expanded on Hutton’s ideas and made them more accessible.
What is the primary theory that Hutton proposed?
Uniformitarianism
This theory suggests that geological processes have remained consistent over time.
What methods did Lyell use to build the Geological Time Scale?
Index fossils
Index fossils are used to identify and date the layers of sedimentary rock.
What processes did Lyell argue have operated in fundamentally the same manner throughout Earth’s history?
- Erosion
- Sediment deposition
- Volcanic action
- Earthquakes
These processes contribute to the understanding of geological changes over time.
True or False: Hutton’s theories gained immediate acceptance in the scientific community.
False
Hutton’s theories were initially difficult to understand and were not widely accepted.
What was a significant challenge in Hutton’s original presentation of his theories?
Buried in a 2000-page book filled with difficult language
This complexity hindered the acceptance and understanding of his ideas.
How did Lyell’s writing style contribute to the acceptance of uniformitarianism?
He used a much more readable style
Lyell’s clarity helped communicate complex geological concepts effectively.
Who was influenced by Lyell’s methods and writing style?
Charles Darwin
Darwin’s work in natural selection was shaped by the geological principles established by Lyell.
What is the primary source of Alberta’s resource wealth?
Microscopic plants and animals that lived in warm tropical seas more than 300 million years ago
This organic matter transformed into oil sands and conventional petroleum reserves.
What role do bacteria play in the formation of Alberta’s petroleum resources?
Bacteria helped transform organic matter into petroleum
This process occurred over millions of years under heat and pressure.
What is the theory of uniformitarianism?
Changes of the past can be explained by geological processes still in operation
This theory was proposed by geologists Hutton and Lyell.
What does the rock cycle explain?
How the three major rock types form and change
The three major rock types are igneous, sedimentary, and metamorphic.
What do rock strata represent?
A record that has taken millions of years to develop
This concept was supported by Hutton and Lyell.
Fill in the blank: The three major rock types are ______.
igneous, sedimentary, and metamorphic
True or False: The processes that formed Alberta’s oil sands are still occurring today.
True
