The Geology of the Upper Mississippi Valley Zinc-Lead District

Lead isotopes as particulate contaminant tracers and chronostratigraphic markers in lake sediments in northeastern North America

“…The large relative abundance of 206 Pb imparted in these ores is fairly unique to UMV-type ores ( Figure 3). Since UMV ore smelting was a dominant Pb source to the atmosphere between 1830 and 1870 for northeastern North America (Figure 2) (Heyl et al, 1959) and a peak in 206 Pb/ 207 Pb is observed in several other archives downwind of the UMV (Gobeil et al, 2013;Graney et al, 1995;Kelly et al, 2009;Kemp et al, 2012;Lima et al, 2005;Marcantonio et al, 2002), a peak at this time in…”

“…After this, coal combustion became the dominant source of Pb to the regional atmosphere, identified by lower 206 Pb/ 207 Pb particulates deposited in the river basin soon after the mid-19 th century. Figure 2 shows the importance of UMV ore smelting between 1830 and 1870 (Heyl et al, 1959). Lima et al (2005) argued that 26 this very clear isotope peak could be used to determine the deposition date of deeper sediments in watersheds where it exists.…”

“…It is most likely that this transition is due to increased input due to coal combustion as ore smelting in the UMV region became a less important atmospheric Pb source (Heyl et al, 1959 (Chow and Earl, 1972;Millen et al, 1995). Coal is the most abundant fossil fuel in the world, and by the second half of the 19 th century, its use in North America expanded from steampowered transportation to electricity and steel production (U.S. Department of Energy, 2013).…”

Hydroecological model predictions indicate wetter and more diverse soil water regimes and vegetation types following floodplain restoration

“…The watershed at the downstream end of the study site is 14.1 km 2 and has roughly 250 m of topographic relief, with slopes of 15% or greater covering over one fifth of the basin. Surficial bedrock in the watershed consists of nearly flat-lying Ordovician dolomite and sandstone and some Silurian dolomite in the far northeastern corner [Heyl et al, 1959]. A thin layer of silty loess blankets the uplands and the depth to bedrock is typically less than 2 m. During the Holocene, streams migrated laterally on a layer of gravel deposited on valley bottoms during late Wisconsin periglacial conditions and later winnowed during the change to a Holocene climate [Knox, 2006].…”

The Midcontinent Strategic and Critical Minerals Project; summary and background information to accompany folio of maps of the northern Midcontinent area, latitude 36-46 degrees N. and longitude 88-100 degrees W.

“…These three maps (MF-1835-1) show the other main part of the MVT depositional model mentioned previously specifically, the areal extent, thickness, and carbonate lithofacies of the region's three principal carbonate units that have proven potential as host rocks. As shown in figure 10, from the base up these are (1) the Upper Cambrian carbon?te units (Bonneterre and Eau Claire Formations and equivalents), which are the principal host rocks of MVT deposits in the Southeast Missouri district (Snyder and Gerdemann, 1968); (2) the Middle and Upper Ordovician carbonate units, (Galena Dolomite-Viola Limestone-Kimmswick Limestone and equivalents), host rocks in the Upper Mississippi Valley district (Heyl, 1968); and (3) the Lower Mississippian (Kinderhookian-Osagean-Meramecian) carbonate units (ChouteauBurlington-Keokuk and Ste. Genevieve Limestones and equivalents), host rocks in the Tri-State (Kansas-MissouriOklahoma) district (Brockie and others, 1968) and in the Illinois-Kentucky fluorspar district (Grogan <nd Bradbury, 1968).…”