Topic 13 Interpreting Geologic History Vocabulary
Unlock all answers in this set
Unlock answersquestion
inclusion
answer
Body of older rock within igneous rock
question
extrusion
answer
Lava flows on the Earth's surface and solidifies
question
volcanic ash
answer
Consisting of sand sized and clay sized particles of extrusive igneous rocks shot into the air
question
intrusion
answer
Magma squeezes into preexisting rocks and crystallizes
question
absolute age
answer
Actual age of the rock or an event in years
question
evolution
answer
States that life forms change through time
question
bedrock
answer
An area's local rock covered by soil and other loose materials
question
radioactive decay
answer
Emission of particles and electromagnetic energy
question
index fossils
answer
Fossils used in correlation that have lived over a wide geographic area and are short lived
question
principle of superposition
answer
Rocks are deposited in layers with youngest on top, oldest on the bottom
question
relative dating
answer
Determination of the age of a rock in relation to other rocks or events
question
unconformities
answer
Evidence of buried eroded surfaces
question
carbon-14
answer
Useful isotope with a half life of 5700 years that is used to date fossils or organic remains
question
fossils
answer
Remains or evidence of former living things (bones, shells, footprints...)
question
outgassing
answer
Gases from the Earth's interior seeped out of the crust through cracks in the crust and volcanoes
question
half-life
answer
Time required for half of the atoms in a given mass of an isotope to decay
question
isotopes
answer
Elements exist in several different varieties
question
radioactive dating
answer
Method used to estimate the absolute age of a rock
question
geologic time scale
answer
Divisions of geologic time (Eons, Eras, Periods, Epochs) make up this chart
question
uranium-238
answer
Important radioactive isotope used in dating very old rocks
