Earth history

Earth history

1. ·

   • The three main layers of Earth include the crust (1 percent of Earth's volume), the mantle (84 percent), and the core (inner and outer combined, 15 percent)

2. Bombardment

   • The Late Heavy Bombardment ends. About 4 to 3.8 billion years ago a period of intense comet and asteroid bombardment is thought to have peppered all the planets including the Earth.

3. Geological Time Scale

   • The geologic time scale (GTS) is a system of chronological dating that relates geological strata (stratigraphy) 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.

4. layers of Earth

5. Stratigraphy

   • • the branch of geology concerned with the order and relative position of strata and their relationship to the geological time scale.

6. 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.

7. Relative Dating

   • Relative dating is the science of determining the relative order of past events (i.e., the age of an object in comparison to another), without necessarily determining their absolute age, (i.e. estimated age).

8. 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.

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