Browsing by Author "Boerboom, T.J."
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Item C-13: Geologic atlas of Pine County, Minnesota [Part A](Minnesota Geological Survey, 2001) Boerboom, T.J.Item Information Circular 27. Minnesota Kaolin Clay Deposits: A Subsurface Study in Selected Areas of Southwestern and East-Central Minnesota(Minnesota Geological Survey, 1989) Setterholm, D.R.; Morey, G.B.; Boerboom, T.J.; Lamons, R.C.Large deposits of kaolin-the residual products of the weathering of igneous and metamorphic rocks-are common in southwestern and east-central Minnesota. Thin and discontinuous beds of sedimentary kaolin (resulting from the reworking of the residuum) are less common and volumetrically less significant. The weathering occurred prior to deposition of Late Cretaceous sedimentary strata. Because climatic conditions were uniform within the study area, the differences in the thickness and composition of the residuum are attributable to the mineralogic and hydrologic properties of the parent rock (protolith). Goldich (1938) and others have shown that weathering and the products of weathering are strongly controlled by the mineralogic composition of the protolith. Rocks rich in mafic minerals and plagioclase are generally more extensively weathered, and their residuum is richer in kaolinite. This susceptibility to weathering is evident in the mineralogic composition of the residuum and is reflected in the concentration of kaolin near the top, and in the addition of other minerals with increasing depth. The weathering process is also dependent on the movement of water and other fluids; therefore, permeability is a second important control on the production of kaolin. In igneous and metamorphic rocks, fractures in the form of joints or faults are the primary paths of fluid movement. Weathering follows these paths, and the resulting kaolin deposits mimic the shape and orientation of the structural features. Preservation is the final factor controlling the distribution of kaolin clays. The upper part of the residuum contains the largest amount of clay, but it also is the most vulnerable to erosion. Glacial erosion has had a profound effect on the distribution and thickness of kaolin clay deposits in the state. The thickest deposits are found where Late Cretaceous sediments overlie the kaolin and indicate total preservation of the weathered products.Item M-066 Geologic map of the Illgen City quadrangle, Lake County, Minnesota(Minnesota Geological Survey, 1989) Miller, James D., Jr.; Green, J.C.; Boerboom, T.J.Item M-067 Bedrock geologic map of parts of Koochiching, Itasca, and Beltrami Counties, north-central Minnesota(Minnesota Geological Survey, 1990) Jirsa, M.A.; Boerboom, T.J.Item M-072 Geologic Map of the Doyle Lake and Finland quadrangles, Lake County, Minnesota(Minnesota Geological Survey, 1993) Miller, James D., Jr.; Green, J.C.; Boerboom, T.J.; Chandler, V.W.Item M-075 Bedrock geology of the Cook-Side Lake area, St. Louis and Itasca Counties, Minnesota(Minnesota Geological Survey, 1991) Jirsa, M.A.; Boerboom, T.J.; Chandler, V.W.; McSwiggen, P.L.Item M-081 Bedrock geologic map of the Silver Island Lake, Wilson Lake, and western Toohey Lake quadrangles, Lake and Cook Counties, Minnesota(Minnesota Geological Survey, 1994) Boerboom, T.J.; Miller, James D., Jr.Item M-082 Bedrock geologic map of the Cabin Lake and Cramer quadrangles, Lake and Cook Counties, Minnesota(Minnesota Geological Survey, 1994) Miller, James D., Jr.; Boerboom, T.J.; Jerde, E.A.Item M-085 Bedrock geologic map of the Virginia Horn, Mesabi Iron Range, St. Louis County, Minnesota(Minnesota Geological Survey, 1998) Jirsa, M.A.; Boerboom, T.J.; Morey, G.B.Item M-099 Bedrock geology of the Aitkin 30 x 60 minute quadrangle, east-central Minnesota(Minnesota Geological Survey, 1999) Boerboom, T.J.; Severson, M.J.; Southwick, D.L.Item M-100 Bedrock geology of the Mille Lacs 30 x 60 minute quadrangle, east-central Minnesota(Minnesota Geological Survey, 1999) Boerboom, T.J.; Severson, M.J.; Southwick, D.L.Item M-114 Bedrock geologic map of the Eagles Nest quadrangle, St. Louis County, Minnesota(Minnesota Geological Survey, 2001) Jirsa, M.A.; Boerboom, T.J.; Peterson, D.M.Item M-128 Bedrock geology of the French River and Lakewood quadrangles, St. Louis County, Minnesota(Minnesota Geological Survey, 2002) Boerboom, T.J.; Green, J.C.; Jirsa, M.A.Item M-129 Bedrock geology of the Knife River quadrangle, St. Louis and Lake Counties, Minnesota(Minnesota Geological Survey, 2002) Boerboom, T.J.; Green, J.C.; Jirsa, M.A.Item M-132 Maps of bedrock geology and superimposed magnetic on gravity (SMOG) anomaly for East-central Minnesota(Minnesota Geological Survey, 2003) Jirsa, M.A.; Chandler, V.W.; Lively, R.S.; Boerboom, T.J.Item M-139 Bedrock geology of the Two Harbors quadrangle, Lake County, Minnesota(Minnesota Geological Survey, 2003) Boerboom, T.J.; Green, J.C.; Miller, James D., Jr.Item M-140 Bedrock geology of the Castle Danger quadrangle, Lake County, Minnesota(Minnesota Geological Survey, 2003) Boerboom, T.J.; Green, J.C.; Miller, James D., Jr.Item M-141 Bedrock geology of the Vermillion Lake 30' X 60' quadrangle, northeastern Minnesota(Minnesota Geological Survey, 2003) Jirsa, M.A.; Boerboom, T.J.Item M-147 Bedrock geology of the Split Rock Point quadrangle, Lake County, Minnesota(Minnesota Geological Survey, 2004) Boerboom, T.J.Item M-155 Bedrock geology of the Two Harbors Northeast quadrangle, Lake County, Minnesota(Minnesota Geological Survey, 2005) Boerboom, T.J.; Green, J.C.