Clues of Earth´s Past

Fossil
 are remains, imprints or traces of prehistoric organism.



 Permialized remains
 are fossils in which the spaces inside are filled with organism from groundwater.



 Carbon film
 a thin film of carbon residue is left, forming a silhoutte of the original organism



 Mold
 the hard part might decay or dissolve, leaving behind a cavity in the rock



 Cast
 mineral rich water or other sediment might enter the cavity, form new rock, and produce a copy of the original form


 Index fossils
 are remains of species that existed on Earth for relative short periods of time, were abundant, and were widespread geographically

 Principle of Superposition
 oldest rocks on the bottom

 Relative age
 something is its age in comparison to other things

 Unconformity
 gaps in rock sequence

 Absolute age
is the age, in years, of a rock or other object

 radioactive decay
the process of breaking down isotopes

 Half life
an isotope is the time it takes half of atoms in the isotope to decay


 Radiometric dating
 the process to decrease as the amount of daughter product increases

 Unconformatism:
process that change the landscape around were slow, and he inferred that they were just slow throught Earth history 



Water Erosion

 Runoff

Water that flows across Earth surface.

Channel

Water moving down the same path that creates a groove.

Sheet Erosion

Occurs when water that is flowing as sheet picks up and carry away sediments

 Drainage Basin

Area of  land from which a stream or river collects runoff

Meander

Growed curved that became a broad arc

Groundwater

Water that soaks into the ground in these pores and empty spaces that became part

Permeable


Rock or sediment that has few pores spaces well connected

Impermeable

Rock or sediment that has few pores spaces or not well connected, then flow and bloack the ground water

Aquifer

Layer of permeable rock that let water move freely

Water Table

Upper surface of the zone of saturation

Spring

a source of fresh water
Gayser

Hot spring that erupts periodically  shooting water and stream in air

Longshore

A shore that carry many metric tons of loose

Beach

Deposit of sediments that are  pararells to the shore

Cave

Cracks in the limestone inlarge until an underground opening