The Late Heavy
Bombardment (abbreviated
LHB and also known as the
lunar cataclysm) is an event
thought to have occurred
approximately 4.1 to 3.8
billion years (Ga) ago, at a
time corresponding to the
Neohadean and Eoarchean
eras on Earth
The geologic time scale is a system of chronological
dating that relates geological strata to time. It is used
by geologists, paleontologists, and other Earth
scientists to describe the timing and relationships of
events that have occurred during Earth's history.
Geological Time Scale
Layers of the Earth
The internal structure of the Earth is layered in
spherical shells: an outer silicate solid crust, a
highly viscous asthenosphere and mantle, a
liquid outer core that is much less viscous than
the mantle, and a solid inner core.
Stratigraphy
the branch of geology concerned with the order
and relative position of strata and their
relationship to the geological time scale.
Fossil Record
Fossil record, history of life as
documented by fossils, the remains or
imprints of the organisms from earlier
geological periods preserved in
sedimentary rock
Relative Dating
Relative dating is the science of determining
therelative order of past events (i.e., the age of an
object in comparison to another), without
necessarily determining their absolute age,
Absolute Dating
Absolute dating is the process of
determining an age on a
specified chronology in
archaeology and geology. Some
scientists prefer the terms
chronometric or calendar dating,
as use of the word "absolute"
implies an unwarranted
certainty of accuracy.