GEOL 120: Planet Earth

1. GEOL 120: Planet Earth • Dr. James R. Ebert • Dennison 23 • X3065 • Ebertjr@oneonta.edu

2. Seven “Big Ideas”about our Earth

3. Seven “Big Ideas” about our Earth • Earth can be described as a system of interacting “spheres” and processes. • Energy is transferred within and between spheres. • Earth’s surface is constantly changed by • Interior processes • Surface processes

4. Seven “Big Ideas” about our Earth • Changes occur over vast expanses of time. • Materials are transferred within and between spheres in a massive version of “recycling.” • Life has a long history of interacting with and changing Earth. • Geologists use multiple methods to understand Earth processes and products.

5. 1) Earth can be described as a system of interacting “spheres” and processes. • Geosphere – Earth’s rocky portion • Lithosphere: Crust and uppermost Mantle • Mantle • Outer and Inner Cores • Hydrosphere – Earth’s water • Atmosphere – Earth’s air • Biosphere – Life on and in Earth • Cryosphere – Earth’s ice

6. 2) Energy is transferredwithin and between spheres. Heat Energy is the most important type • Conduction – direct transfer of heat by contact • Radiation – transfer of heat across a distance without direct contact • Convection – transfer of heated material from place to place through gravity acting on differences in density of the materials

7. 3) Earth’s surface is constantly changed byInterior Processes • Movement of lithospheric plates • Formation of ocean basins • Formation of igneous rock • Formation of Mountains • Formation of igneous rock • Formation of metamorphic rock • Rates may be • Slow – movement of plates • Rapid – earthquakes, volcanic eruptions

8. 3) Earth’s surface is constantly changed bySurface Processes • Weathering – breakdown of rock • Erosion – movement of rock fragments • Deposition – settling of moving fragments • Formation of sedimentary rocks

9. 4) Changes occur over vast expanses of time. • Earth is ancient • Planet formed 4.6 billion years ago • Earth processes produce recognizable products • These products provide evidence for past operation of processes • Even slow processes can produce great changes over great lengths of time

10. 4) Changes occur over vast expanses of time. • Sequences or histories of these processes can be compiled from across the Earth • Fossils are very useful for determining relative ages • Numerical ages can be determined • Radioactive decay provides numerical ages for rocks that contain radioactive elements

11. 5) Materials are transferred within and between spheres in a massive version of “recycling.” • Law of Conservation of Matter • Matter can neither be created nor destroyed • Matter can be changed from one form into another • Water is recycled among the hydrosphere, atmosphere, lithosphere and cryosphere • Gasses are recycled among the atmosphere, hydrosphere and lithosphere • Rocks are recycled in the lithosphere with help from Earth’s interior heat and from circulation in the hydrosphere

12. 6) Life has a long history ofinteracting with and changing Earth. • Life appeared on Earth at least 3.8 billion years ago • Life has changed through time (evolution) as documented by fossils • The biosphere depends on the lithosphere, hydrosphere and atmosphere • The biosphere modifies these other spheres through life processes acting over long periods of time

13. 7) Geologists use multiple methods to understand Earth processes and products. • Earth is a complex planet and must be studied at various scales • Satellite remote sensing, seismic imaging, regional mapping using GPS and GIS, single outcroppings, hand samples, thin sections, scanning electron micrographs • Owing to tremendous scale, both spatial and temporal, we use models, simulations, etc. to study some processes • We use quantitative, qualitative, experimental and deductive methods to study Earth

14. 7) Geologists use multiple methods to understand Earth processes and products. • Modern processes provide analogies to help understand ancient products • Ancient products provide insights into the workings of modern processes • Everything we know about Earth, like all scientific knowledge, is subject to revision as we learn more

15. Seven “Big Ideas” about our Earth • Earth can be described as a system of interacting “spheres” and processes. • Energy is transferred within and between spheres. • Earth’s surface is constantly changed by • Interior processes • Surface processes • Changes occur over vast expanses of time. • Materials are transferred within and between spheres in a massive version of “recycling.” • Life has a long history of interacting with and changing Earth. • Geologists use multiple methods to understand Earth processes and products.