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Dr. Ken Ridgway - Geologist
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Do you know that we can read the history of the Earth in rocks?  Many of the rocks that you can see at the top of a mountain, for example, may have formed at the bottom of the ocean.  Rocks that form at the surface of the earth are called sedimentary rocks.  These types of rocks have layers, and each layer often has fossils.  As a geologist, when I study the layers of fossils and sediment in sedimentary rocks, I can “read” their history.  Many natural resources, like coal, oil, and groundwater come from sedimentary rocks. Understanding the connection between sedimentary rocks and natural resources can help us make good decisions about how to find, use, and preserve these resources in the future.

Examples of the history that I can learn by studying sedimentary rocks are changes in climate of the Earth.  A serious question for scientists right now has to do with global warming, which means that the Earth’s climate is getting warmer.  Although this is a big concern because humans are contributing to the rise of the Earth’s temperature, it is not the first time in the Earth’s history that the temperature has risen.  We’ve also had periods of global cooling.  However, since humans haven’t always kept written records, the best way for us to learn about these changes is to “read” the record of climate change found in sedimentary rocks.

Fossils, which are imprints of plants or animals in rock, can also be made by pollen, a powder-like material produced by many plants and transported by the wind.  By looking at fossilized pollen in rocks, scientists can figure out not only when the Earth’s climate was cooler or hotter, but also what effect those temperature changes had on life on Earth.  This information can help us answer important questions about how life might change in the future because of global warming.

I can also learn about the history of pollution by looking at sedimentary rocks.  For example, the Great Lakes used to be very polluted about thirty years ago.  Many companies around the lakes dumped waste products into the water, which was very harmful to the wildlife.  Now the lakes are much cleaner, but the chemicals and poisons that were in the water in the 1970s are now in the sediment at the bottom of the lakes.  By taking cores of the sediment in lake bottoms, we can start to understand the history of pollution in an area. 

My main reason for choosing geology was that I love nature, and I love being outdoors.  As a professor at Purdue University and as a geologist, my students and I have the chance to spend a lot of time in some of the most beautiful places on Earth.  It’s important to me that my students appreciate the Earth because some of them may go on to work for petroleum and environmental companies and help make important decisions about environmental issues.

I also chose to become a geologist because I feel a responsibility to the Native American communities.  I’m Lenape (Delaware) Indian, and I lived a pretty traditional lifestyle as a kid.  Who I am has a lot to do with the way I was raised, so I wanted to do something that would help my community.  As a geologist, I can help Native American communities make good decisions about how to use the natural resources that exist on reservations.  By looking at the sedimentary rocks, I can tell where the best places are to find oil and natural gas, to locate drinking water wells, and safe locations for landfills.  I believe that it’s very important for there to be Native American geologists to help make these decisions in ways that respect the land and the traditions of the people living on it.

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