GEOL 120: Planet EarthGEOL 120: Planet Earth

• Dr. James R. Ebert• Dennison 23• X3065• Ebertjr@oneonta.edu

Seven “Big Ideas”Seven “Big Ideas”about our Earthabout our Earth

Seven “Big Ideas” about our EarthSeven “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

Seven “Big Ideas” about our EarthSeven “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.

1) Earth can be described as a system of 1) Earth can be described as a system of interacting “spheres” and processes.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

2) Energy is transferred2) Energy is transferredwithin and between within and between

spheres.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

3) Earth’s surface is constantly changed by3) Earth’s surface is constantly changed by Interior ProcessesInterior 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

3) Earth’s surface is constantly changed by3) Earth’s surface is constantly changed by Surface ProcessesSurface Processes

• Weathering – breakdown of rock• Erosion – movement of rock fragments• Deposition – settling of moving fragments• Formation of sedimentary rocks

4) Changes occur over vast expanses of time.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

4) Changes occur over vast expanses of time.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

5) Materials are transferred within and between 5) Materials are transferred within and between spheres in a massive version of “recycling.”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

6) Life has a long history of6) Life has a long history ofinteracting with and changing Earth.interacting 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

7) Geologists use multiple methods to understand 7) Geologists use multiple methods to understand Earth processes and products.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

7) Geologists use multiple methods to understand 7) Geologists use multiple methods to understand Earth processes and products.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

Seven “Big Ideas” about our EarthSeven “Big Ideas” about our Earth1) Earth can be described as a system of interacting

“spheres” and processes.2) Energy is transferred within and between

spheres.3) Earth’s surface is constantly changed by

1) Interior processes2) Surface processes

4) Changes occur over vast expanses of time.5) Materials are transferred within and between

spheres in a massive version of “recycling.”6) Life has a long history of interacting with and

changing Earth.7) Geologists use multiple methods to understand

Earth processes and products.