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Research about St. Louis County, Minnesota

Source-linked reports with geographic coverage including St. Louis County, Minnesota.

4 recordsLinked to original sources
USGS1978

A paleolimnological comparison of Burntside and Shagawa Lakes, northeastern Minnesota

The paleolimnological records of Burntside and Shagawa Lakes in northeastern Minnesota reveal that these two adjacent lakes have been limnologically distinct for many years prior to the late 19th century activities of white men that polluted Shagawa Lake. Although both lakes occur within the same vegetation type and share much of their water, the diatom stratigraphy of their bottom sediments indicates that Burntside Lake was less productive in its natural state than Shagawa Lake. The causes for this natural difference are not clearly known, but differences in relative size of drainage area and in bedrock geology may he responsible. Intensive white settlement around Shagawa Lake beginning in 1866 supplied nutrients that increased its productivity and finally supported the massive blooms of blue-green algae that characterize culturally eutrophic lakes. Burntside Lake was spared such intensive eutrophication, but its diatom record shows that nutrients derived from shoreside recreational cabins and related construction activity are increasing the lake's productivity. The results of this study show that paleolimnological studies may provide better comparative information for lake rehabilitation programs than do biological and chemical analyses of contemporary unpolluted water bodies.

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USGS1966

Reconnaissance of the geology and ground-water resources in the Aurora area, St. Louis county, Minnesota

The Aurora area is a glaciated upland of drift-mantled slopes, channels, swamps, and glacial-lake plains. It covers about 24 square miles of the eastern part of the Mesabi Iron Range in northeastern Minnesota. A deep narrow channel along the Embarrass River, the principal outlet of a former large glacial lake north of the Embarrass Mountains, lies partly within the area. The deposits in the report area consist of bedrock and unconsolidated glacial drift. The 'bedrock belongs to the Animikie Group of late Preeambrian age and consists of taconite (an iron-rich silicate rock) in the northern part and slightly metamorphosed argillite in the middle and southern parts. Bedrock is exposed only in the open-pit iron mines. Large quantities of ground water are pumped from porous and permeable ore zones in the St. James Mine. Small quantities of ground water are obtainable from openings along bedding planes and fractures in the argillite. Unconsolidated deposits consisting of till and water-laid glacial and alluvial materials mantle the bedrock to depths ranging from about 20 feet in the north-central part of the Aurora area to more than 300 feet near the Embarrass River. Thick deposits of sand and gravel in the Embarrass channel are capable of yielding large quantites of water. At places along the Partridge River glaeiofluvial deposits (glacial sediments deposited in running water) could yield moderate to large quantities of water. Sandy to bouldery till yields small quantities of water to domestic wells. Well yields in the Aurora area range from less than 5 gpm (gallons per minute) to about 250 gpm from a well tapping an ore body. The specific capacity of wells penetrating ore zones ranges from about 7 gpm per foot of drawdown to 25 gpm per foot of drawdown. Although no attempt has been made to develop a high-yield well in the sand and gravel deposits of the Embarrass channel, more than 5,000 gpm is pumped from sumps which collect water from these deposits in the Embarrass mine. Most domestic wells yield about 5 gpm and are drilled and finished in sand or gravel in either the bouldery till or glaciofluvial deposits. Ground water from the unconsolidated deposits is hard and commonly contains large, undesirable amounts of iron and manganese. Water from the 'bedrock aquifers contains less iron and manganese than does water from the unconsolidated deposits.

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USGS1961

Exploratory drilling for ground water in the Mountain Iron-Virginia area, St. Louis County, Minnesota

The Mountain Iron-Virginia area is a broad, southwest-trending valley in the central part of the Mesabi Range. The valley, which heads in the Laurentian Divide, and covers about 120 square miles, coincides approximately with a bedrock valley filled with as much as 150 feet of glacial deposits. A complex sequence of glacioaqueous sediments made up of clay, silt, sand, and gravel was delineated from test holes drilled at 238 sites. These sediments range in thickness from 0 to 125 feet and can be considered a hydrologic unit, bounded below by sandy till or bedrock and above by as much as 60 feet of clayey till. The piezometric surface ranges from 0 to about 70 feet below land surface, thus, the glacioaqueous deposits are not everywhere completely saturated. In places, however, the water is under artesian pressure. Within the Mountain Iron-Virginia area about 50 square miles are underlain by deposits 20 feet or more in thickness of silt, sand, or gravel that constitute an aquifer that is a large potential source for additional water supplies. Except for iron and manganese, which are present in excessive amounts in some wells, the water meets U.S. Public Health Service standards for municipal supplies. Pumping tests of wells in the permeable sand or gravel deposits at five sites indicate that yields of several hundred gallons per minute and possibly as much as 2,000 gpm (gallons per minute) can be expected.

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