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Prentice Hall
Chapter 4 section 1-2 vocab
Term | Definition |
---|---|
Fossil | The preserved remains or traces of living things |
Sedimentary rock | The type of rock that is made of hardened sediment |
mold | A fossil formed when an organism buried in sediment dissolves, leaving a hollow area |
cast | A fossil that is a solid copy of an organism's shape, formed when minerals seep into a mold |
petrified fossil | a fossil in which minerals replace all or part of an organism |
carbon films | A type of fossil consisting of an extremely thin coating of carbon on a rock |
trace fossil | a type of fossil that provides evidence of the activities of ancient organisms |
paleontologists | a scientist who studies fossils to learn about organisms that lived long ago |
scientific theory | a well-tested concept that explains a wide range of observations |
evolution | The process by which all the different kinds of living things have changed over time |
extinct | Describes a type of organism that no longer exists anywhere on earth |
relative age | The age of rock compared to the ages of rock layers |
absolute age | The age of rock given as the number of years since the rock formed |
law of superposition | The geologic principal that states that in horizontal layers of sedimentary rock, each layer is older then the layer above it and younger than the layer below it |
extrusion | An igneous rock layer formed when lava flows onto Earth's surface and hardens |
intrusion | An igneous rock layer formed when magma hardens beneath Earth's surface |
fault | A break in Earth's lithosphere along which the rocks move |
unconformity | A place where an old , eroded rock surface is in contact with a newer rock layer |
index fossil | Fossils of widely distributed organisms that lived during only one short period |