A team of research scientists working in the Rocky Mountains this summer hopes to find keys to unlock geological secrets buried deep underground for nearly two billion years.
The University of Colorado at Boulder is among 14 American universities and one from Germany taking part in the project known as the Continental Dynamics -- Rocky Mountain Project, or CD-ROM.
CU-Boulder has three of the 19 scientists involved in a series of seismic experiments stretching more than 600 miles between Saratoga, Wyo., and central New Mexico. The route will be studded with seismic instruments every half mile.
Results from mine blasts and a handful of smaller explosions, together with the activities of specially designed vibrating trucks on the surface, will feed information to that network of 1,200 seismometers.
In addition to the approximately 1,200 seismic instruments stretching from Wyoming to New Mexico, 50 additional earthquake recording instruments were put in place in April and June. They will remain in place for a year, picking up small vibrations from earthquakes as far away as Japan and South America and allowing scientists to "see" several hundred miles down into the Earth.
This summer a handful of the Vibroseis trucks will trundle 375 miles along separate north and south segments of the route, sending synchronized vibrations into the earth through large pads.
The vibrations will be recorded by the sensitive seismometers and used to create profiles up to 30 miles deep, going right through the Earth’s crust.
The seismic reflection data bouncing back from different rock layers deep below the surface will produce the Earth’s equivalent of a medical ultrasound image, says Assistant Professor Anne Sheehan, of CU’s geological sciences department and CIRES, the Cooperative Institute for Research in Environmental Sciences. CIRES is a joint institute of CU-Boulder and the National Oceanic and Atmospheric Administration.
The computer-generated, three-dimensional maps which emerge from these late summer and fall experiments should give scientists a clearer understanding of what lies beneath this planet’s surface all the way down to where the Earth’s crust meets the mantle.
In conjunction with the seismic studies, Professor Lang Farmer, also of the geological sciences department and CIRES, is coordinating geochemical and geophysical studies of fragments of the lowermost crust present in volcanic rocks found along the Colorado/Wyoming border.
These crustal fragments will be used to help interpret the seismic data, to determine the age of the lowermost crust and to test the possibility that the lower crust may have been the original source of Colorado gold deposits.
Researchers believe this study, supported by $2.7 million in funding from the National Science Foundation, will help increase our knowledge of how the Rockies were formed and the interaction between mountain ranges in Wyoming and Colorado.
Sheehan said about two billion years ago Colorado’s rocks were volcanic islands -- similar to Japan and the Philippines today -- before they were pushed northward, "crashing" into Wyoming where the rocks are about 800 million years older.
The Rocky Mountain region is of fundamental interest in studying the dynamics and evolution of the whole North American continent, she said.
On a more practical level, improved knowledge of geologic structures arising from the geology project may lead to a better understanding of earthquake hazards, natural resources and scarce water resources such as deep aquifers.
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