A third process can occur, wherein living organisms extract ions dissolved in water to make such things as shells and bones.
This type of sedimentation is called biochemical sedimentation.
he question of the ages of the Earth and its rock formations and features has fascinated philosophers, theologians, and scientists for centuries, primarily because the answers put our lives in temporal perspective.
Until the 18th century, this question was principally in the hands of theologians, who based their calculations on biblical chronology.
A giant impact collision with a planet-sized body named Theia while Earth was in its earliest stage, also known as Early Earth, is thought to have been responsible for forming the Moon.
Over time, the Earth cooled, causing the formation of a solid crust, and allowing liquid water to exist on the surface.
Another type of sedimentary deposition occurs when material is dissolved in water, and chemically precipitates from the water.
This type of sedimentation is referred to as chemical sedimentation.
Earth formed around 4.54 billion years ago by accretion from the solar nebula.
When ‘parent’ uranium-238 decays, for example, it produces subatomic particles, energy and ‘daughter’ lead-206.
Isotopes are important to geologists because each radioactive element decays at a constant rate, which is unique to that element.
When the energy of the transporting current is not strong enough to carry these particles, the particles drop out in the process of sedimentation.
This type of sedimentary deposition is referred to as clastic sedimentation.
Geologists often need to know the age of material that they find.