Embark on a captivating journey through the annals of time with the geologic time activity worksheet answer key, a treasure map guiding us through Earth’s rich history. From the formation of towering mountains to the evolution of life, this comprehensive resource unlocks the secrets of our planet’s dynamic past.
Delve into the intricacies of geologic time periods, unraveling the significance of fossils in reconstructing ancient environments, and exploring the challenges and advancements in geologic time scales. Prepare to be captivated as we uncover the forces that have shaped our planet, from the colossal to the microscopic.
Geologic Time Periods: Geologic Time Activity Worksheet Answer Key
Geologic time is divided into hierarchical units based on the relative and absolute ages of rocks and fossils. These units include eras, periods, epochs, and ages.
The geologic time scale is organized into four eras: the Precambrian, Paleozoic, Mesozoic, and Cenozoic. Each era is further divided into periods, which are then divided into epochs, and finally into ages. The approximate dates for each geologic time period are shown in the following table:
| Era | Period | Epoch | Age | Approximate Date (mya) |
|---|---|---|---|---|
| Precambrian | Hadean | N/A | N/A | 4.6
|
| Precambrian | Archean | N/A | N/A | 4.0
|
| Precambrian | Proterozoic | N/A | N/A | 2.5
|
| Paleozoic | Cambrian | N/A | N/A | 541
|
| Paleozoic | Ordovician | N/A | N/A | 485
|
| Paleozoic | Silurian | N/A | N/A | 444
|
| Paleozoic | Devonian | N/A | N/A | 419
|
| Paleozoic | Carboniferous | Mississippian | N/A | 359
|
| Paleozoic | Carboniferous | Pennsylvanian | N/A | 323
|
| Paleozoic | Permian | N/A | N/A | 299
|
| Mesozoic | Triassic | N/A | N/A | 252
|
| Mesozoic | Jurassic | N/A | N/A | 201
|
| Mesozoic | Cretaceous | N/A | N/A | 145
|
| Cenozoic | Paleogene | Paleocene | N/A | 66
|
| Cenozoic | Paleogene | Eocene | N/A | 56
|
| Cenozoic | Paleogene | Oligocene | N/A | 34
|
| Cenozoic | Neogene | Miocene | N/A | 23
|
| Cenozoic | Neogene | Pliocene | N/A | 5.3
|
| Cenozoic | Quaternary | Pleistocene | N/A | 2.6
|
| Cenozoic | Quaternary | Holocene | N/A | 0.0117
|
FAQ Summary
What is the significance of fossils in geologic time?
Fossils provide invaluable clues to the age of rocks and the history of life on Earth. They allow scientists to reconstruct past environments and trace the evolution of species over millions of years.
How does radiometric dating help determine the age of rocks?
Radiometric dating utilizes the decay rates of radioactive isotopes to determine the age of rocks. By measuring the ratio of parent to daughter isotopes, scientists can calculate the time elapsed since the rock’s formation.
