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Chapter 8/9 review
Chapter 8 assessment
| Question | Answer |
|---|---|
| Geologists estimate the Earth to be ____________ years old. | 4.6 billion |
| The principle that geologic processes that occurred in the past can be explained by current geologic processes called ____________. | uniformitarianism |
| Layers of rock, called ___________, show the sequence of events that took place in the past. | strata |
| Even though all three classes of rock can form layers, the ones most commonly studied are _____________. | sedimentary |
| The boundary between two 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 _________________. | superstition |
| The principle that a fault or intrusion is younger than the layers it cuts through is called the law of ____________. | crosscutting relationships |
| 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 as the Grand Canyon which is millions of years old. | erosion |
| In general, about 30 cm of sedimentary rock are __________ over a period of 1,000 years. | deposited |
| Some sedimentary rock layers show annual layers called ____________. | varves |
| Which layer 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 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-14 |
| 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 do not survive such low temperatures. | ice |
| When minerals in groundwater percolate through buried organic matter, the result is nearly perfect mineral replica of the object. This process is called ___________. (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 is from an animal is called a __________. | coprolite |
| 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 index fossils to locate deposits of ______________. | oil and natural gas |
| The geologic time scale is a scale that divides Earth's history into _____ __________. | time intervals |
| Scientists are able to determine the absolute ages of most rock layers in a geologic column by using ________ _______. | radiometric dating |
| o determine the age of a specific rock, scientists might correlate it with a layer in a geological column that has the same relative position and _______ ____________. | fossil content |
| Geologic periods can be divided into __________. | epochs |
| Precambrian time ended about ________________. | 542 million years ago. |
| The most common fossils that occur in Precambrian rock are _________________. | cyanobacteria |
| The first vertebrates appeared during the _____________ _________. | Paleozoic era |
| The age of reptiles is the name commonly given to the ____________ _____________. | Mesozoic Era |
| The first flowering plants appeared during the _____________. | Cretaceous Period |
| The Age of Mammals is the name commonly given to the _________ _______________. | Cenozoic Era |
Created by:
lyndseyjeffries
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