Overview

In this section you will find materials that support the implementation of EarthComm, Section 1: The Evolution of the Geosphere.

Learning Outcomes

• Analyze and interpret data to determine the distribution and age of Earth’s geologic provinces.
• Analyze and interpret data to determine the age distribution of the basement rocks of the North American continent.
• Obtain information about the formation and development of Earth’s geosphere.

Inquiring Further

1. To learn more about Bowen’s reaction series, visit the following web sites:
   
   Igneous Rocks, USGS
   Looks at the formation of igneous rocks, including Bowen’s reaction series and fractional crystallization.
    
2. To learn more about ophiolites, visit the following web sites:
   
   Ophiolites, Oregon State University
   Describes ophiolites and the plate tectonic processes under which they form.  Includes information about the Samail ophiolite in southeastern Oman.
   
   Ophiolites, University of Oregon
   Examines the five distinctive layers of ophiolites.
   
   The Ocean Basins, Tulane University
   Discusses ophiolites and how they form.
    
3. To learn more about the period of heavy bombardment, visit the following web sites:
   
   The Archaen Eon and Hadean, Univ. of California Museum of Paleontology
   Brief overview of Earth’s early formation.
   
   Impact Processes on the Early Earth, Univ. of Vienna
   Describes the impact processes that occurred during the period of late heavy bombardment.

Asteroid Impacts Once Made the Earth’s Oceans Boil for A Whole Year, Smithsonian Magazine
Describes the violent origins of Earth's beginning and the possibility of boiling oceans.

Earth’s Formation and its Interior Structure, University of Wisconsin-Madison
Overview of Earth’s formation, including the bombardment by meteoric debris.

Is there any record of meteorite impact in the Archean rocks of North America?, Lunar and Planetary Institute
Examines the role of meteorite impact on crustal evolution.

4. To learn more about greenstone belts and metal ores, visit the following web sites:
   
   Gold, Volcano World
   Examines the occurrence of gold in greenstone belts.
   
   Greenstone, Miami University
   Describes the ways in which greenstone belts are significant.  Includes the significant metal deposits including copper, iron, and gold associated with greenstones.

Resources

To learn more about this topic, visit the following web sites:

Crustal Evolution

Age of the Earth, USGS
Explains how scientists have determined the age of Earth.

The Hadean, Indiana University
Tells about the Hadean Eon and early life.

The Archaen Eon and Hadean, Univ. of California Museum of Paleontology
Brief overview of Earth’s early formation.

Impact Processes on the Early Earth, Univ. of Vienna
Describes the impact processes that occurred during the period of late heavy bombardment.

Evolution of Continents and Oceans, Indiana University
Overview of the processes that form new crust and consume old crust.  Also looks at the evolution and features of continental crust, including shields and platforms.

The Precambrian Era, Michigan State University
Describes the geologic history of Earth, including its formation and the evolution of its early crust.

The Evolution of Continental Crust, University of Washington
Examines the conditions required for the formation of continents.  Compares the planets and the extent to which those conditions exist.

Weathering and the Early Rock Cycle

Hadean-Archaen Environment, US National Institute of Health Library of Medicine
Examines the Archean and crustal evolution.  Describes earliest evidence for carbon cycle, running water and weathering and erosion and life.

What is the Rock Cycle, Idaho State University
Looks at the formation, break down, and reformation of rock, including weathering processes.

Development of the Magnetosphere

The Magnetosphere: Our Shield in Space, NASA
Describes Earth’s magnetic field and its relationship to solar wind.

The Earth's Magnetosphere, NASA
Overview of Earth’s magnetic field and its interaction with solar wind.

The Development of the North American Continent

Skeletal Outline of North America's History, Indiana University
Lecture notes describe the formation of the North American Continent beginning from Earth’s formation.

Historical Geology of North America, University of Maryland
Examines North American provinces, their origins, and their development.

The Development of the North American Cordillera

Geologic History of Western US, University of Colorado
The geologic structure and timing of the development of the western margin of the North American continent.