The Geologic Record and the Environment

Geologic Time Evidence suggests Earth is approximately 4.6 billion years old! Earth’s history is divided into sections based on… ◦Climate ◦Earth’s surface ◦Living Organisms

Uniformitarianism Processes that occur on Earth’s surface today have occurred for 4.6 billion years. ◦Weathering ◦Erosion

◦Deposition ◦Tectonic plate activity ◦Volcanoes ◦Folding ◦Faulting ◦Continental drift

Evidence of Past Environments Ripples found in rocks. ◦Moving water Basalt or Granite (igneous rocks) ◦Volcanoes

Mud and Shale ◦Lake, swamp, or other small body of water Sand or Sandstone ◦Desert or Ocean

Evidence of Past Climates Rocks ◦Till rocks left by glaciers. ◦Rocks with iron (red) formed in deserts. ◦Salt in rocks from evaporated oceans.

Fossils ◦Animals with adaptations to warm/cold climates. ◦Woolly mammoth and coral reef.

Landscape ◦Glacier erosion ◦Glacier deposition

Ice cores ◦Temperature (water isotopes) ◦Atmosphere composition (amount of CO2) ◦Precipitation ◦Volcanic eruptions ◦Ocean size ◦Deserts ◦Forest fires

Global Warming The average global temperature has increased over 1 degree F in 100 years. The amount of CO2 (greenhouse gas) has increased very fast!

Evidence for Global Warming Average global temperature Sea level rising Shrinking ice caps Warmer oceans Fewer glaciers

Why is this bad?