Chatting with the faculty

Headline: Chatting with the faculty

Name: David Osleger

Position: Lecturer

Department: Geology

What do you do?

I am a type of geologist called a stratigrapher. Stratigraphy is a big word meaning that we read the layers of rock that are basically the pages of history of our planet. From these layers of rock we can tell things like ancient climates [and] ancient environments. The history of evolution is written in the types of rocks that I look at.… In a very broad, general way, I am an earth historian.

How did you get interested in this field?

I became interested in geology as an undergraduate simply because I like being outdoors; I like nature and I like science. It is the same characteristics that all geologists have. You like to combine your interests in science with your appreciation for the outdoors. I like looking at a landscape and understanding and what it means, how it got there and what it is telling me.

I try to convey that in the classes that I teach. I try to get students to look around and understand why the Central Valley is flat, why the Sierras are scalloped, and get them to visualize ice age glaciers and where the granite of the High Sierras came from.

What is your research on?

What I am most interested in is the history of climate in the High Sierras. We can tell when there were phases of extreme raininess in the High Sierras versus times of extreme extended drought. I am most interested in paleoprecipitation, times when the water budget in the High Sierras fluctuated between times of extreme wetness and times of extreme dryness. And that has implications for us today because we are very much dependent on snowfall and runoff from the Sierras for our water needs.

The other research that I have worked on in the recent past is a sort of broad topic called ancient ocean chemistry. You could sample rocks from specific locations of a specific age. The ones we look at are in Mexico because they happen to be very well exposed down there in the Sierra Madre Oriental. From these rocks we do a whole variety of chemical techniques such as isotopic and other geochemical analyses to try and tease out what the ancient oceans may have been like that those rocks were deposited in.

Have you made any great discoveries?

That’s tough because all scientists like to think that they have made an impact on one level or another and I like to think that I have in my own discipline. The paper I am having published now on Lake Tahoe should open up a lot of people’s eyes to extreme climatic events. Storms unlike [any] we’ve ever seen before in human history and episodes of drought that are much more extensive and widespread in time, in terms of duration, than we have ever experienced in recent history.

Humans today live in a very benign, soft, stable climate system, but in the recent past – a few thousand years ago, (the cores I have in Tahoe go back to 7,000 years) – we’ve experienced the High Sierra, we’ve experienced thousands of years of very extreme storminess and hundreds of centuries to millennia of extreme drought. So if this does anything to open people’s eyes about the way the climate works and its effect on California and its economy, then that should be considered significant.

What classes do you teach?

This quarter I am teaching a class called Solar System – it is really fun. Last quarter I taught a class called California Geology. I teach a class called Geology of National Parks. I teach Geology 1, which is Introductory Geology. I also teach in the nature and culture program with a colleague in the English department named Michael Ziser.

I have been teaching NAC 1, Intersections of Culture and Nature, for the past fours years and I really like it because I am interested in the overlap between the human, the cultural and literary aspects of nature relative to the science.

Where is the most exotic place you have gone to conduct your research?

As a geologist, I am very fortunate in that I get to travel a lot. I have spent time in Mexico, the American West and the Canadian Rockies. I have looked at rocks in Italy and Spain. The most exotic place has probably been in Oman, in the Middle East.

Are there areas that are best for collecting sediment?

Some places are better than others. Typically [sediments] are found in high mountain ranges. The Southern Canadian Rockies are all bare rock because they have been scraped clean by glaciers during the last ice ages. They are high and steep, but they are also beautiful and tell an interesting story. So we gravitate toward places above tree lines or deserts where the rocks are most likely to be well-exposed.

How can geology be applied to the world today?

Geology has a direct impact, especially [in] California, because of the current climate change and also through natural hazards. If you live in California, you live in earthquake country. The greater knowledge we have about natural hazards like earthquakes, floods, random rare volcanic events and landslides all factor into land use – how we go about using our land in the safest and effective way.

The other issue that geology is directly related to is resource use. Many of our resources are not renewable: oil, coal, natural gas, many minerals; and our entire society is dependent on fossil fuels. So geologists are both involved in finding these fossil fuels and exploiting them, but we’re also interested in what to do next.

Fossil fuels will not be around forever, and so we are interested in determining when the so called peak oil is going to happen and what to do for our energy needs as the fossil fuels are depleted. The three primary disciplines that geology plays directly into our lives are natural hazards, climate change and non-renewable resources.

This interview was conducted by YASSMIN ATEFI. She can be reached at science@californiaaggie.com.