Types of Rock
Sedimentary, Igneous, and Metamorphic
Strata means "layers"
What is weathering?
Weathering is the chemical and physical processes that break down rocks at Earth's surface
What is deposition?
The process of depositing sediment that has been moved by erosion.
4.6 billion years old
Which type of rock forms from cooled magma or lava?
Igneous Rock
What is a fossil?
A fossil is the remains or traces of ancient plants and animals
Name two types of weathering. (Hint: remember your comic strip notes)
Biological (animals burrowing, roots growing)
Chemical (acid rain, oxidation/rusting)
Physical (frost wedging, abrasion)
This a landform that is formed by deposition. Hint- this happens at the end of a river where it meets a larger body of water.
A delta is an example of a landform created by deposition.
What is the geologic time scale?
A timeline that organizes Earth’s history through different eras and periods.
What is the name of the type of rock formed through high heat and high pressure?
Metamorphic Rock
What type of rock usually contains fossils?
Sedimentary rocks typically carry fossils because they are made of layers of sediments that build up over time.
How does weathering differ from erosion?
Weathering is what breaks down rocks. Erosion is when water, wind, ice, or other forces move rocks and sediment.
Weathering does the breaking, erosion does the taking
Explain how human actions can impact deposition in rivers.
Construction and damming can change water flow and affect where sediments are deposited. Pollution can also affect deposition in rivers.
What does the term 'mass extinction' mean?
Mass extinction is a widespread and rapid decrease in the number and variety of animals on Earth.
What needs to happen for a sedimentary rock to transform into a metamorphic rock?
It would need to go under high heat and high pressure.
The rock layer closest to the surface is ___________________________ in age than the layers beneath it.
younger
Define 'erosion' and name two types of erosion
Erosion is the process where wind, water, ice or other forces MOVE rocks/sediment.
Types include: wind, water, glaciers, gravity
What is the law of superposition and why is it important for scientists?
The Law of Superposition states that in undisturbed rock layers, the oldest layers are at the bottom. It's important because it helps us understand Earth's history. It teaches us about the plants and animals that used to live here and important events that have happened.
Absolute = exact age of something
Relative = about/approximately how old something is
Which rock is formed from compaction and cementation?
Sedimentary rocks
How can geologists use strata to learn about Earth's history?
Strata can give us clues about different periods in time and the plants and animals that lived millions of years ago. It can also help us understand our planet and predict what might happen in the future.
Describe ways water can contribute to weathering?
Water can seep into cracks in rocks, freeze overnight, and eventually cause the rocks to crack and break.
John finds a fossil 2 feet under the ground. May finds a fossil ten feet below John's. Whose fossil is older and how do you know?
May's fossil will be older. I know this because the farther down you dig, the older the materials and fossils you will most likely find.
What are the four major eras in Earth's geologic time scale? Hint: this was in the Generation Genius video on geologic time- they divided the football field into these four eras.
Precambrian, Paleozoic, Mesozoic, and Cenozoic