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Chapter 8 Assessment
Review over the three sections in Chapter 8
Question | Answer |
---|---|
Geologists estimate that the Earth is ________ years old | 4.6 Billion |
The principle that geologic processes that occurred in the past can be explained by current geologic processes is called_______ | Uniformitarism |
Layers of rock, called _______, show the sequence of events that took p;lace in the past. | Strata |
Even though all three classes of rock can form layers, the ones most commonly studied are ________ | Sedimentary |
The boundary between 2 beds of rock is called a _______ | Bedding plane |
The principle that a sedimentary rock layer is older than the one above it is called the law of _______ | Superposition |
The principle that a fault or intrusion is younger than the layers it cuts through is called the law of ________ | Crosscutting Realationships |
The absolute age of a rock layer is its _________ age | Numeric |
Using the rate of ________ to determine absolute age would be less accurate for a surface feature such a s the Grand Canyon which is millions of years old. | Erosion |
In general, about 30cm of of sedimentary rock are _______ over a period of 1,000 years. | Deposited |
Some sedimentary rock layers show annual layers called _________ | Varves |
Which layer (summer or winter) is composed of darker finer grains? | Winter |
Atoms of the same element that have different numbers of neutrons are called ________ | Isotopes |
The original radioactive isotope is called the _________ isotope | Parent |
The half-life is the time required for half of a radioactive sample to break down by decay to form the _______ isotope | Daughter |
What is the half-life of Uranium-238? | 4.5 billion years |
The ages of wood, bones, shells and other organic remains embedded in rock can be determined through _________ dating | Carbon |
The scientific study of fossils is called _________ | Paleontology |
Some insects become fossilized in hardened tree sap called __________ | Amber |
Organisms buried in ________ do not decay, because bacteria does not survive in such low temperatures | Ice |
When minerals in groundwater percolate through buried organic matter, the result is a nearly perfect mineral replica of the object. This process is called _________ (Hint: it often happens to wood) | Petrification |
A fossil residue of a leaf that makes a "shadow" on sedimentary rock is called a _______ | Carbon film |
Fossilized dung or waste from an animal is called a _________ | Caprolite |
The stones from the digestive tracts of dinosaurs are called _________ | Gastroliths |
Fossilized tracks, borings, or burrows are called ________ fossils | Trace |
Fossils that occur only in rock layers of a particular geologic age are called _________ fossils | Index |
Geologists also use these fossils (most previous question) to locate deposits of ________ | Oil or Natural gas |