Download History of the Earth

Vocab
Fossil
 Remains, imprints, or traces of prehistoric organisms
Permineralized Remains
 Fossils in which the spaces inside are filled with
minerals from groundwater
Carbon film
 A thin film of carbon residue that forms a silhouette of
the original organism
Mold
 A cavity in a rock left behind from a decaying
organism
Cast
 A copy of the original object formed by mineral-rich
water or other sediment
Index fossil
 Remains of species that existed on Earth for relatively
short periods of time, were abundant, and were
widespread geographically.
Principle of Superposition
 The oldest rocks are on the bottom and the rocks
become progressively younger toward the top
Relative age
 An objects age in comparison to the ages of other
things
Unconformities
 A gap in a rock sequence
Absolute age
 The age, in years, of a rock or other object
Radioactive decay
 The process of breaking down
Half-life
 The time it takes for half of the atoms in the isotope to
decay
Radiometric dating
 Calculating the absolute age of a rock by measuring
the ratio of parent isotope to daughter product in a
mineral and by knowing the half-life of the parent
Uniformitarianism
 Principle that states that Earth’s processes occurring
today are similar to those that occurred in the past
Weathering
 The breaking down or disintegration of substances
such as rocks and minerals by physical, chemical, or
biological changes
Erosion
 The movement of sediment or soil from one location
to another by means of water, wind, or ice
Deposition
 When particles carried by water, ice, or wind are
deposited in another location
Metamorphic rock
 Rocky material experiences intense heat and pressure
in the crust of the earth.
Igneous rock
 Formed when magma cools and makes crystals.
Sedimentary rock
 Form at or near the earth's surface at relatively low
temperatures and pressures primarily by: deposition
by water, wind or ice