LAWRENCE — University of Kansas geologists have synthesized the mineral dolomite at a low temperature without the aid of microorganisms — a feat that scientists have been trying to accomplish for almost a century.
Announced in a paper published today in The Proceedings of the National Academy of Sciences (PNAS), this work will eventually provide researchers with more accurate tools for understanding climate change and give geologists better methods for finding new sources of petroleum, said Jennifer Roberts, associate professor of geology and lead author of the paper. This research also represents a major step forward in solving what geologists call The Dolomite Problem.
In their research, Roberts and her team were able to grow dolomite at a temperature of 25 degrees Celsius (77 degrees Fahrenheit) in their laboratory in an abiotic environment. Abiotic means that while organic material was present, it was not actively reproducing. The KU researchers were able to show that a certain kind of coating on organic matter, known as a carboxylated surface, acts as a catalyst to create dolomite.
Previously, researchers had only been able to produce dolomite at temperatures of 80 to 250 degrees Celsius (176 to 482 degrees Fahrenheit), or had used live microorganisms to help synthesize the mineral.
Dolomite is a carbonate mineral commonly found in sedimentary rock. The mineral plays key roles in both the economy and science. Dolomite forms major hydrocarbon reservoir rocks, holding large parts of the world’s petroleum reserves, in areas such as the Middle East and Kansas. The mineral also serves as a proxy enabling scientists to interpret the chemistry of ancient fluids and to estimate temperatures on Earth millions of years ago. Understanding the climate of the geologic past enables scientists to create climate change models.
“Understanding where and how dolomite forms allows petroleum geologists to create predictive models so they can better locate hydrocarbon reservoirs,” Roberts said. “Better understanding the formation of dolomite also enables us to calibrate models that will help us figure out climate change in the future.”
Understanding the formation of dolomite will also solve a mystery that has long baffled geologists. Researchers have been able to determine that while the mineral formed abundantly in the geologic past, it seldom is discovered to be forming today, and then only at temperatures above 50 degrees Celsius (122 degrees Fahrenheit).
“There was a whole lot of dolomite formed in the ancient, and not much of it formed in the modern,” Roberts said. “That flies in the face of one of the basic tenets of how we operate as geologists, which is that the present is the key to the past. In other words, we believe that the geologic processes that work in the present also worked in the past.”
The KU research has helped solve one of the major aspects of The Dolomite Problem, Roberts said, by unlocking the mechanism that allows dolomite to form in open spaces in rocks at a low temperature. Future phases of the research will focus on other parts of this problem.
Joining Roberts in the paper are Paul Kenward, a KU doctoral student at the time of this study and now a postdoctoral researcher at the University of British Columbia; David Fowle, associate professor of geology; Robert Goldstein, associate dean of the College of Liberal Arts and Sciences and Merrill W. Haas Distinguished Professor of Geology; Luis González, chair of the Department of Geology and professor of geology; and David Moore, of KU’s Microscopy and Analytical Imaging Laboratory.
The Department of Geology is part of the College of Liberal Arts and Sciences. The College encourages learning without boundaries in its more than 50 departments, programs and centers. Through innovative research and teaching, the College emphasizes interdisciplinary education, global awareness and experiential learning. The College is KU's broadest, most diverse academic unit.