Earth History

4. - The process by which rocks are broken down into small grains and soil.
6. - The true age of a rock or fossil that tells scientists the number of years ago a rock layer formed.
7. - cylinders of ice drilled from glaciers and ice sheets
8. - The law that states in any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on bottom
11. - Rock that has formed when sediment transported by water (rivers, lakes, and oceans), ice (glaciers), and wind compress to form a solid. Sedimentary rocks are often deposited in layers, and frequently contain fossils.
14. - The entry of molten rock or magma into or between other rock formations
16. - The remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock

1. - A comparison of age based on which object (or event) is older or younger than some other object or event.
2. - Rock that is formed when magma or lava cools and forms a solid. Igneous rock forms intrusions and extrusions.
3. - The divisions that show timing and relationships between events that have occurred during the history of the Earth.Paleontologist - A scientist that studies fossils
5. - determining of the age of an object based on the known rates of decay of radioactive isotopes of various elements
9. - The movement of magma onto the surface of the earth through volcano craters and cracks in the earth's crust, forming igneous rock.
10. - A division of geologic time marked by distinctive developments and events
12. - The action of surface processes (such as water flow or wind) that remove soil, rock, or dissolved material from one location on the Earth's crust, then transport it away to another location.
13. (geologic time) - one of several subdivisions of geologic time enabling cross-referencing of rocks and geologic events from place to place
15. - A widely distributed fossil of a narrow range in time, used to determine the age of related rock formations