Magma immiscibility in the shonkin sag and square butte. An early morning or sunset walk to the summit of crown butte will reveal magnificent views, ancient local history and geology unique to montana. Geology and differentiation of round butte laccolith central montana. Geology and ore deposits of the clinton mining district, missoula county, montana. Ms book and mineral company montana geology and mining history catalog i federal publications. Butte history overview butte history and lost butte. The estimated population for 2004, based on 2000 us census is butte 34,606 and montana 909,453. The term is sometimes used for an elevation higher than a hill but not high enough for a mountain. Trails east of the ranch yard lead to the top of the laccolith and permit easy examination of an entire cross section by traversing down the canyon draining to the southwest. Magmatic differentiation of square butte laccolith, central. Charlie russells square butte profiles of montana geology. Yet several key landmarks remainthe historic late 19th century stone jail is listed in the national register of historic places. Lists of series titles, including cost and availability, can be found in the mbmg publications catalog.
Montana agate comes from near the yellowstone river in montana. Its just a recognizable piece of montana geology, said jim combs, an active. The two most iconic ones are the one 22 miles west of great falls visible from some parts of great falls, and the one featured in this post, which is 50 miles east of great falls. Detailed descriptions, photos and maps guide you to some of the best gem collecting sites in idaho and western montana. Gibson, is in stores and museum gift shops around butte. Shonkin sag and square butte laccoliths are at the eastern edge of the highwood mountains as part of the central montana alkalic province. Since 2006, the montana department of transportation has installed nearly 50 roadside geological markers. Geology and ore deposits of the butte district, montana, 1912, cl, 262 pages, 25 plates, 109 figs.
Falls, montana, six miles south of shonkin sag laccolith, and two miles west of square butte laccolith figures 1 and 2. Montana bureau of mines and geology publications geology. Geologic road signs montana department of transportation. The bald butte mine is a gold and silver mine located in lewis and clark county, montana at an elevation of 6,880 feet. The highest elevation of the cascade county square butte is 4,728 feet 1,441 m square butte is easily visible for many miles around. The montana bureau of mines and geology produces a variety of map products for the state of montana. In square butte, view the historic jail, located at the west end of town, it was built from shonkinite quarried locally. Frequently asked questions about butte and montana. The flattopped butte juts 2,400 feet above the surrounding plains and is visible for a radius of seventyfive miles in many directions. Frequently asked questions about butte and montana your.
The dominant phase, the butte quartz monzonite bqm, has been dated at 75. Square butte is located along montana highway 80 6. Welldated sites in montana range from about 11,500 yr b. The laccolith lies entirely within the geraldine, montana, 1. Montana agate is probably the most well known rock from montana. Magmatic differentiation of square butte laccolith central montana. Part or all of this report is presented in portable document format pdf. A field guide to some of the states best rockhounding sites.
Two phases of mineralization by evan charles gearity a thesis submitted in partial fulfillment of the requirements for the degree of master of science in earth science montana state university bozeman, montana. Evelyn lived in terry, mt but spent time in the square. The town gets its name from a nearby geologic formation a flattopped butte which juts 2,400 feet above the surrounding plains and is visible for a radius of seventyfive miles. Some of the topics include the early history of gold, silver and copper mining in the butte area, insight into the geology of its mining areas, the local distribution of gold, silver and copper ores, as well their. Montanas colorful history includes the stories told through geology.
The batholith was shaped by magma shoved upwards by volcanic eruptions about 60 to 70 million years ago. Hydrogeology of the cascadeulm area montana scholarworks. Mountain goats were relocated to the butte years ago and a herd still exists there. Issue 74 of professional paper paperback or softback by weed, walter harvey and a great selection of related books, art and collectibles available now at. The facebook page has many historic photos of butte, and the butteanaconda nhld project showcases many historic buildings. Both laccoliths are internally differentiated and contain a variety of rock types, including shonkinite, syenite, and pegmatite. Once served by the milwaukee road, few travelers find the town today. The butte mining district, spanning an area of some 25 square miles, is located in the southern portion of the boulder batholith, a multiphased intrusive complex situated in southwestern montana. A laymans guide to the treasure state special publication montana bureau of mines and geology alt, david d on. The geologic formation of square butte is a laccolith, a mass of igneous rock formed from magma that did not surface but instead spread out, forcing the overlying. Evolution of square butte laccolith, eastern highwood mountains, montana.
State geology usbm publications usgs publications ore deposits paleontology books petroleum mineralogical record. The town of square butte gets its name from a nearby geologic formation. Hank armstrong has written several books about the area near square butte. The butte mine district is essentially within the city limits of butte.
Magnetiteilmenite boundary in the western atlanta lobe of the idaho batholith, in. This cross section can be viewed from the flat creek road, which intersects montana 80, 0. The butte mining district of montana by us department of. One that i found fascinating was about southeastern montana photographer evelyn cameron.
Southwest montana was something like this about 78 million years ago. Finding the landscapes of charlie russell great falls tribune. Indeed, the distinctive features of square butte and round butte known in the. Included are rare insights into the gold, copper and silver mines of butte, montana together with hard to find maps and photographs. Please practice handwashing and social distancing, and check out our resources for adapting to these times. Founded in 1879, butte, the richest hill on earth, is located in silver bow county in southwest montana.
Petrography and geology of the igneous rocks of the highwood. One of my favorite central montana landmarks and small railroad towns is square butte. The adel mountains volcanic field is an ancient volcanic field of heavily eroded 75millionyearold igneous rocks about 40 miles long and 20 miles wide 800 square miles, or 2,071 square kilometers in westcentral montana about. Magma immiscibility in the shonkin sag and square butte laccoliths. The shonkin sag and square butte laccoliths of central montana differentiated. Each interpretive sign describes the geologic and paleontological wonders of the treasure state to help share montanas story.
Although bretz concept sparked a lively controversy, most geologists today agree that the. Geology of the garnet mountain quadrangle, gallatin county, montana. Shonkin sag and square butte laccoliths, montana hyndman. Square butte is an unincorporated community in chouteau county, montana, united states, named for the unique rock formation of the same name slightly southwest of the town. Age of the alaska bench formation, central montana. The name channeled scablands was first used in the early 1920s by geologist j harlen bretz of the university of chicago, who made a comprehensive study of the region and proposed the idea that the erosional features were the result of a gigantic flood. The 26inch by 40inch butte, montana, richest hill on earth. Missoula growing giant pumpkins, caring for fragile dinosaur eggs, protecting unique boulders and playing a final musical tribute are the storylines for a new episode of the popular montanapbs travelogue series backroads of montana. Montana geodes with descriptions of where to look for them. Both laccoliths are internally differentiated and contain a variety of. Look on the horizon to the right of the bison to see square butte, round butte, and the highwoods.
The shonkin sag and square butte laccoliths of central montana differentiated in place from single alkalic magmas to produce syenite and shonkinite through a. Its called square butte for a reason central montana. Indeed, this may be the oneandonly classic example of a laccolith that is really a butte in the 21stcentury sense of the word. And read an interview with gibson, here, and on kxlf here. The shonkin sag laccolith is on the northeast flank of the highwood mountains in sec.
Between the communities of square butte and geraldine, two prominent geologic features dominate the. Montana geodes with descriptions of where to look for them check out tripadvisor members 1,227 candid photos and videos of mbmg mineral museum. Geology ore deposits butte district montana abebooks. Lost lake and square butte in central montana big sky walker. The city of 34,000 is nearly on the continental divide at an elevation of 5549 feet in the rocky mountains flanked by the boulder mountains to the north and. Geology of the cleveland quadrangle bearpaw mountains. Square butte is a name used for 11 buttes in montana. However, early man was well established by 11,500 yr b. Butte is in the heart of a huge granite formation called the boulder batholith that stretches from south of helena to north of dillon. It is approximately 44 mi 71 km east of great falls and 54 mi 87 km northwest of. A geological survey bulletin 1141p a description of the geologic features and economic resources of the area united states government printing office, washington.
Media in category geology of montana the following 24 files are in this category, out of 24 total. Two of the most prominent buttes are located in a cascade county, montana, about 22 miles 35 km due west of great falls and in b chouteau county, montana, about 50 miles 80 km due east of great. Square butte country club 226 broadway ave, square butte, montana 59446 rated 4. Buttes history is rich and varied, so much so that dozens of books recount its remarkable story. Mining childhood offers a fresh perspective on montana history.
Drawing from a broad range of archival materials and oral histories, the book offers a childseye view of key events in buttes history and considers how social, political, and economic forces shaping life in butte left their marks on children. For best results viewing and printing pdf documents, it is recommended that you download the documents to your computer and open them with adobe reader. The time of earliest arrival of man in the montanawyoming area is controversial. There are eleven square buttes in montana alone, among which this is the only one that meets the current lexical requirements. Square butte in cascade county, montana, is located about 22 miles 35 km due west of great falls, montana. A laymans guide to the treasure state special publication montana bureau of mines and geology.