Summary of ground-water hydrology of the Cambrian-Ordovician aquifer system in the northern Midwest, United States

Abstract

Investigations, Circulars, publications of general interest (such as leaflets, pamphlets, booklets), single copies of Earthquakes & Volcanoes, Preliminary Determination of Epicenters, and some miscellaneous reports, including some of the foregoing series FOREWORD THE REGIONAL AQUIFER-SYSTEM ANALYSIS PROGRAM The Regional Aquifer-System Analysis (RASA) Program was started in 1978 following a congressional mandate to develop quantitative appraisals of the major groundwater systems of the United States. The RASA Program represents a systematic effort to study a number of the Nation's most important aquifer systems, which in aggregate underlie much of the country and which represent an important component of the Nation's total water supply. In general, the boundaries of these studies are identified by the hydrologic extent of each system and accordingly transcend the political subdivisions to which investigations have often arbitrarily been limited in the past. The broad objective for each study is to assemble geologic, hydrologic, and geochemical information, to analyze and develop an understanding of the system, and to develop predictive capabilities that will contribute to the effective management of the system. The use of computer simulation is an important element of the RASA studies, both to develop an understanding of the natural, undisturbed hydrologic system and the changes brought about in it by human activities, and to provide a means of predicting the regional effects of future pumping or other stresses. The final interpretive results of the RASA Program are presented in a series of U.S. Geological Survey Professional Papers that describe the geology, hydrology, and geochemistry of each regional aquifer system. Each study within the RASA Program is assigned a single Professional Paper number, and where the volume of interpretive material warrants, separate topical chapters that consider the principal elements of the investigation may be published. The series of RASA interpretive reports begins with Professional Paper 1400 and thereafter will continue in numerical sequence as the interpretive products of subsequent studies become available.

Groundwater and climate dynamics derived from noble gas, 14C, and stable isotope data

“…The hydrostratigraphy of the area consists of Paleozoic marine sedimentary rocks, consisting of interbedded sandstones, siltstones, shales, and dolomites (Young, 1992;Feinstein et al, 2005aFeinstein et al, , 2005b. Regional hydrostratigraphy is given in Figure 1.…”

“…Because groundwater is a very important regional water resource, a number of studies have been conducted to investigate the deep sandstone aquifer of southeastern Wisconsin (e.g., Bahr, 1991a, 1991b;Young, 1992;Grundl and Cape, 2006). Previous groundwater fl ow modeling (Feinstein et al, 2005a(Feinstein et al, , 2005b, isotopic studies (Perry et al, 1982), and some unpublished 14 C data (D.I.…”

Evidence for preferential flow through sandstone aquifers in Southern Wisconsin

“…The Tunnel City Group has previously been lumped into an upper bedrock aquifer (Dane and LaCrosse Counties, Wisconsin) or a comprehensive regional aquifer (Rock County, Wisconsin) in order to describe and simulate groundwater flow using numerical models (Krohelski et al, 2000;Gaffield et al, 2002;Hunt et al, 2003). Elsewhere, the Tunnel City Group has been treated as a confining unit along with the overlying, more silty and dolomitic St. Lawrence Formation (Young, 1992;Mandle and Kontis, 1992). In a recent assessment of the hydrostratigraphy of southeastern Minnesota, Runkel et al (2003) described the lithostratigraphic and hydrogeologic complexity of the Tunnel City Group, also referred to as the Franconia Formation, and noted variability in secondary porosity due to bedding plane fractures (see also Runkel et al, this volume).…”

Geochemical Factors Controlling Radium Activity in a Sandstone Aquifer

“…An unconsolidated surficial veneer of Quaternary deposits overlies the eroded bedrock (Young 1992;Mickelson et al 1984). An unconsolidated surficial veneer of Quaternary deposits overlies the eroded bedrock (Young 1992;Mickelson et al 1984).…”

“…In descending order, from youngest to oldest, the stratigraphic system consists of the Sinnipee Group ( City, Wonewoc, Eau Claire, and Mount Simon sandstones) (Young 1992;Borman and Trotta 1975;Gonthier 1975;and Young and Batten 1980). Although the system is generally considered a sandstone aquifer, interlayered carbonates are common.…”