Evidence used to decipher Earth's prehistoric past is hidden in its rocks. Sedimentary rocks have sequentially recorded many Earth-shaping events and different environments over geologic time. These layers of rocks may be read much as one reads the pages of a book, although many of the pages and numerous characters are missing from this history, especially for the earliest chapters in the story. It is up to the clever and imaginative student of geology to put the pieces together, interpret the clues, and reconstruct the missing parts to tell Earth's story.Top
The Grand Canyon provides one of the best places on the planet to begin looking back into Earth's history. Students join Major John Wesley Powell on his epic adventure down the Colorado River in small wooden boats in 1869. The Canyon's sandstones, shales, and limestones contain fossils that provide evidence of over 1.5 billion years of changing environments. Students recreate the processes that contribute to the creation of these kinds of rocks, from making sand from chunks of granite to observations of stream tables used to demonstrate that rock particles can be removed from one location (eroded), transported by water, and deposited in a distant location. They make sandstone, shale, and limestone to verify that particulates from massive rocks can be reconstituted and cemented together to form new rocks.
The study of Earth history challenges students to consider deep time--time measured in millions and billions of years, rather than the minutes, hours, and days with which students are more familiar. They begin by putting their own lives into a time perspective, considering changes year by year. Students then gradually work toward an appreciation for the length of time that the Earth has existed.
As they observe and compare the processes happening today, both in the classroom and in the world outdoors, they begin to visualize how these same processes may have acted to create the rocks in the Grand Canyon. And by looking carefully for fossil clues in the rocks, they can infer the conditions that were present in the environments in which the rocks formed.
The guiding focus behind the FOSS Earth History course is for students to consider what they know about Earth's past (e.g., 250 million years ago what is now the Colorado Plateau was a warm, shallow sea) and then ask the question, "How do we know?" Through their inquiries, students begin to understand the magnitude of time and the extent of the processes that have shaped the Earth and may even begin to consider how these same processes are shaping the planet today and will continue to do so in the future.
PISCES Project Supporters
|National Science Foundation|
Biogen Idec ||
Boston Scientific ||
Girard Foundation ||
Hewlett Packard Foundation ||
Qualcomm Incorporated ||
San Diego Science Alliance || Sprint || The Legoland Foundation ||
Richard D. Winter Jr. Matching Gift || A generous gift from the Edgar Hardy Family || The San Diego Foundation's Reuben H. Fleet Discretionary Fund & Colonel Frank C. Wood Memorial Fund || Todd and Mari Gutschow Family Foundation || Anne Prause Blue || Proxima || Marilyn and Martin Colby