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Montana Geologic Map Products
Montana's diverse and challenging geology is evident, from its western mountains lifted and folded by tectonics and sculpted by glaciers, to its vast eastern plains partly overlain by glacial till and dissected by wind and water.
The Geologic Map of Montana includes three parts. Plate 1 is the geologic map of the state (approx. 4x7ft). Plate 2 provides supporting and complementary information including the correlation chart of surface rocks with generalized lithologic information. The third part is a booklet containing all figures shown on plates 1 and 2, additional figures, the description of map units, list of source maps for plate 1, and references cited for all plates, figures, and text.
By JOHN HARRINGTON, Independent Record 10/16/07
After more than half a century, Montana has a new official geological map, with more than triple the detail of the last edition.
The previous version of the state geological map, published in 1955, included 76 distinct geological units. The map unveiled Monday in a ceremony in the Capitol Rotunda features 324. A geological unit is a rock formation that is distinctively recognizable from everything else around it and extends over a distance, according to Ed Deal, state geologist and director of the Montana Bureau of Mines and Geology at Montana Tech in Butte.
"I never thought I'd get so old that the geology changed," joked Gov. Brian Schweitzer, who said a framed version of the new map will hang in the Montana Room in the governor's office.
Deal said the new map, roughly 50 by 80 inches and accommpanied by a separate legend and detailed comb-bound brochure with additional information, was authored by four mappers in the bureau.
"But they compiled the work of hundreds of mappers who did the more detailed work over several decades," he said. "In 55 years we've learned a lot more about the state, there's been more mapping and better accessibility."
Speaking to students from Helena High as well as the Project for Alternative Learning at the unveiling, Schweitzer said understanding what lies beneath the surface of the Treasure State has economic ramifications. Schweitzer said he intends to ask the next Legislature to designate one particular formation, the Madison limestone, as Montana's official State Geologic Feature.
Evident in the Bridger Mountains, the Little Beltsand in Lewis and Clark Caverns, Schweitzer said Madison limestone, the state's "most important" feature, is also valuable as an underground aquifer and as a source of trapped natural gas and oil. In the future, Schweitzer said the formation may prove beneficial as a storage place for carbon dioxide, or for "carbon sequestration," the trapping of the greenhouse gas beneath the ground to slow global warming.
"We have some of the most remarkable geology in the world," Schweitzer said. "The geology that's exposed today won't change during your lifetime, but it will change during the next thousands and millions of years."
It shouldn't be a half-century before the map is updated this time around. Deal said that unlike the previous edition, this map is stored electronically and printed on demand, meaning the computer files can be updated as needed to accommodate new information about the state's bedrock layers.
Copies of the map are available starting this morning for $60 (high-quality plain paper) or $85 (glossy) through the Bureau of Mines and Geology Web site at www.mbmg.mtech.edu.
Reporter John Harrington:406-447-4080 or john.harrington@helenair.com.
Leslie McCartney / The Montana Standard
After 52 years, the state of Montana is getting a geologic update, thanks to the Montana Bureau of Mines and Geology.
Montana Bureau of Mines and Geology compilers Jeffery Lonn and Susan Vuke display the new, just released, geologic map of Montana. The newly released Geologic Map of Montana — a color-coded treasure of geologic data — was unveiled Monday in Helena for Gov. Brian Schweitzer.
"The last new map was in 1955," said Ed Deal, director and state geologist for the bureau, based at Montana Tech. The new map's release coincides with National Earth Science Week, which raises awareness of the importance of Earth sciences.
While it took longer than the expected to
complete, Deal said that actually worked
out in the bureau's favor, since new programs and equipment meant that didn't have to pay another entity to publish the map."Technology has changed so much; now we have a 'plotter' and we can produce it ourselves," Deal said.
New technology also allows the map to be updated easily and more frequently.
Years of work went into the project, from geologists in the field and cartographers, to four bureau employees who compiled the voluminous information. They include Susan Vuke, Karen Porter, Jeffrey Lonn and David Lopez.
The information — billions of years of geologic formations — will be used by various people, including contractors, developers, consultants, geologists, state agencies, seismologists and students.
"It gives a fairly broad overview of the state's geology " Deal said "Several people devoted decades to this"
He added that not everyone will be happy with the changes and how they are presented.
"Geology doesn't change, but our interpretations do," he said.
For example, 1955's map the age of the rocks, shows 76 geologic units; 2007's shows 324 such units.
According to the U.S. Geological Survey, geologic units are named and defined by the geologists who made tne map based on their observations of the kinds of rocks and their investigations of rhe age of the rocks.
"And you can compile things a thousand different ways," Deal said.
Reporter Leslie McCartney may be reached at leslie.mccartney@mtstandard.com.
