Val W. Chandler, geophysicist extraordinaire, has been my friend and professional colleague for almost forty years. We have worked together on projects too numerous to mention, beginning in 1979 only a few weeks after Val escaped to the blissful cool of Minnesota after a brief stint at Amoco, Inc. in the heat and humidity of Houston, Texas. His personal accomplishments and contributions to diverse joint projects at the Minnesota Geological Survey, and beyond, are remarkable in their scientific breadth. It is a privilege for me to be Val’s citationist for the 2018 Goldich Medal.
Val was born and raised in Indianapolis, Indiana. After graduating from high school in 1967, having excelled academically and also athletically in track and field, he entered Indiana University. There he majored in geology and continued his athletic career as a “weight-man” on the IU varsity track team. In 1970 he won the Big Ten Conference championship in discus and placed second in shot-put. Fortunately for us, he declined the overtures of professional football scouts attracted by his impressive size and strength and instead decided to pursue a graduate education in the earth sciences at Indiana, where he obtained an M.S. in geophysics, and at Purdue, where he acquired a Ph.D. in geophysics in 1978 under the tutelage of Prof. Bill Hinze. His graduate work in both universities involved extensive practical applications of magnetic and gravity methods.
Val’s professional contributions to understanding the geological framework of Minnesota and the greater Lake Superior region can be subdivided into three main parts. His first challenge was to plan and then supervise the production of a state-wide, high-definition aeromagnetic map of Minnesota. That project, spread over roughly 12 years, involved negotiating contracts with private-sector geophysical mapping firms, performing quality-control tests of the data, writing progress reports to university and governmental administrators, and securing funding for successive segments of the project from the Minnesota legislature. More or less coincident with all of this, Val oversaw a parallel effort to complete a high-quality gravity survey of the state that involved faculty and students from the University of Minnesota and Northern Illinois University and included important contributions of data from private-sector sources. The net result of these efforts was a set of digital potential-field geophysical maps of the state that were widely acknowledged to be among the very best in North America.
After the geophysical mapping of Minnesota was essentially finished, about 1992, Val devoted more and more of his time to geological interpretation of the geophysical data. In this work he collaborated in various ways with geologists in the MGS, such as myself, Mark Jirsa, Jim Miller, and Terry Boerboom, and with many geologists in adjacent states and provinces. Furthermore, he contributed to important national and international geophysical projects such as the development of the gravity anomaly map of North America (1988) and the magnetic anomaly map of North America (2002). All along, Val was assiduous in applying the latest technological advancements to the presentation and interpretation of geophysical data. Among the techniques he perfected is the so-called “SMOG” presentation in which gravity and magnetic anomalies are combined. The SMOG acronym means Superimposed Magnetics On Gravity. A SMOG map shows the first vertical derivative of the magnetic signature (typically in grayscale) draped over the second vertical derivative of the gravity signature (typically shown in bright colors). The value of modern computing power in producing these maps and other analytical tools cannot be overemphasized, and Val’s efforts in developing and improving computational applications, such as SMOG maps and various digital modeling methods, have proven to be powerful aids to the geologic mapping of Precambrian terranes beneath glacial cover in Minnesota and the rest of the Lake Superior region.
As we all know, the Precambrian rocks of the Lake Superior region host a wealth of metallic mineral resources, and the potential for discovering and developing future economically viable Precambrian mineral deposits in covered areas has long been an attractive possibility to exploration companies and politicians. Indeed, that possibility was emphatically presented to Minnesota policy makers in the late 1970s, during a deep recession in the Minnesota iron-mining industry. It gave rise to a push for “minerals diversification” and created a political environment in which the importance of geophysics to the diversification effort could be successfully argued. That set of conditions brought Val to us, and his presence has produced dividends. Today we can make much better geologic maps of Precambrian terranes than we could before digital aeromagnetic and gravity maps became a reality, and consequently can make more credible assessments of mineral potential.
In recent years, however, the sense of urgency expressed in the public and political sectors has changed. Clean water, especially clean groundwater, has supplanted metals as the political “ore of choice”. This is reality. Val, in the third chapter of his career, has pivoted from the geophysical interpretation of Precambrian rocks to the pursuit of techniques that aid three-dimensional hydrogeologic mapping of Quaternary glacial deposits. He has applied passive seismic methods to the estimation of sediment thickness above sub-Quaternary bedrock, an important parameter in aquifer delineation and groundwater management. He continues to perfect passive seismic techniques and works in close cooperation with soft-rock stratigraphers and hydrogeologists at MGS and affiliated state agencies.
Last but not least, Val is a teacher. He is an adjunct professor of geophysics in the school of earth sciences at the University of Minnesota. He has taught various undergraduate-level geophysics courses over the years and advised or co-advised several graduate students pursuing M.S. or Ph.D. degrees. He has long been an advocate for advancing the understanding and sensible application of science in the public sphere.
Submitted by David Southwick