What Is The Geological Makeup Of Missoula Valley

Rapids in Swan River as it enters Flathead Lake This 1846 map fatigued past Jesuit priest, Father Peter John De Smet, is perhaps the primeval published depiction of the geography and h2o courses of the Flathead region.

In 1840 Male parent De Smet left St. Louis Missouri, charged with bringing the Catholic organized religion to the native tribes of the Northern rockies. For the next six years he worked to institute missions for the Flatheads, Pend Orielles, and Blackfeet and profoundly influenced their acceptance of Christian theology.

Returning to St. Louis in 1846 De Smet published several pop books on Indian life and continued his efforts to financially support the Indian missions of the Rockies.

Although De Smet visited the Flathead, this map was based on data obtained from the native inhabitants of the area. The Kootenai referred to Swan Lake as "Nasoquat", merely De Smet gave information technology the name of "Lac Hughes", in honor of Curvation bishop John Hughes.

THE SWAN VALLEY – GEOGRAPHY AND GEOLOGY De Smet1846 Map

The Swan Valley is located in northwest Montana, roughly at latitude 47° 33" N; longitude 113° 45" W. It is west of the Continental Divide and thus enjoys a Pacific Northwest blazon of climate, with more moisture and moderate temperatures than eastern Montana. The Swan Valley is virtually 93 miles long and drains an area of roughly 671 square miles. The valley is bounded by the Swan Mount Range to the east and the Mission Mountain Range to the westward. The Swan Range rises abruptly from the valley flooring of near three,000 feet to peaks above 9,000 feet high – frequently within 10 horizontal miles of the river.[1]

These 2 mountain ranges both extend south across the headwaters of the Swan River (which flows northerly into Flathead Lake at Bigfork) to the Clearwater River drainage, which flows southerly to join the Blackfoot and Clark Fork rivers. A low divide at about 4,200 anxiety separates these two river basins, and the combined drainages are referred to as the "Seeley -Swan" Valley.

Both the Swan and Mission ranges are Precambrian sedimentary formations, created by long faults or lines of surface motion. An upward-thrust block mistake scarp forms the steeply rising Swan Range to the east. Both ranges accept formations tilting down to the east. Related to the sedimentary foundation, no significant mineral deposits have been found in the Swan Valley.[2]

The Swan Valley was probably affected past several glaciers during the ice ages, resulting in "U" shaped canyons and an undulating valley flooring with many pocket-size lakes and bogs. Geologists believe that i such ice sheet flowed south in the Rocky Mount trench from the Yukon to the Flathead Valley, where it was dissever by the Mission Mountains, with one portion flowing downwards the Swan Valley. Most one-half of the Swan basin is now covered with glacial deposits.[iii]

Annual precipitation in the valley ranges from 20-xxx inches at lower elevations to 80 inches or more in the mountains. Average almanac precipitation in this roughly 430,000 acre basin is near 1.v million acre feet, or a basin boilerplate of 41 inches. Comparison this precipitation to the Montana country-broad boilerplate of 15 inches per year shows that the Swan Valley is unusually moisture for our state. This relatively high precipitation and the above noted glacier-created bogs, basins, and lakes makes the Swan Valley truly unique, as the bowl is a huge water reservoir. In fact, well-nigh 16 per centum of the Swan basin surface is covered by some type of water – lakes, rivers, ponds, and bogs. This is the highest proportion of surface coverage of any river drainage in Montana, and represents a bully natural resource of increasing value.

High atmospheric precipitation with deep winter snows encouraged dense forests and discouraged both permanent villages by Native Americans and afterward settlement past Euro-Americans. The lack of mineral deposits further delayed development of the surface area relative to other locations in Montana. These all go important factors in the present environment of the Swan Valley and its history, which will be reviewed in other chapters. SOURCES/BIBLIOGRAPHY Curtis, Lori S., Flathead Watershed Sourcebook: A Guide to an Boggling Place, Flathead Community of Resources Educators, 2010 ——-, Swan Valley and Condon Community Profile, Swan Valley Community Council Sept 21, 2010 Whitehorse Associates, Source and Ecological Classification, Swan River Basin Montana, Fws.gov/Montana field role, Jan, 1996

Source: http://www.swanlakers.org/geography-geology/

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