Fossils

Fossils

Are thr remains, imprints, or traces of prehistory organisms.





Are the fossils in which the spaces inside are filled with minerals from groundwater.





Carbon film

 A thin film of carbon residue is left, forming a silhouette of the original organism.

Mold

The hard part might decay or dissolve leaving behind a cavity rock.

Cast

Mineral-rich water or other sediment might enenter the cavity, form ew rock, and produce a copy of the orginal object.

Index fossils

Are the remains of species that existed on Earth for relatively short periods of time, were abundant, and were widespread geogrephically.

Principle of superposition

The oldest rocks are on the bottom and the rocks become progressively younger toward the top.

Relative Age

Something is its age in comparison to other things.

Unconformities

Gaps in rock sequence.

Absolute age

Age, in years, of a rock or other object.

Radioactive decay

Process os breaking down.

Half-life

The time it takes for half of the atoms in the isotope to decay.

Radiometric dating

Measure the ratio of a pafrent isorope to daughter product in a mineral and by knowing the half-life of the parent.

Unoformitarianism

Scottish scientist James Houtson used it.

Permineralized remains