Summary: The Precambrian bedrock of Minnesota records a rich geologic history from the Mesoarchean (~3600 Ma) through the Mesoproterozoic (~1000 Ma). Many of the events recorded in Minnesota’s ancient rocks are recognized to have impacted our understanding of changing geologic processes through time, the evolution of early life, modern economics, and the landscape of Minnesota we recognize today. From exploring some of the earliest known continental crust in the world and the origin of modern plate tectonics recorded in the Superior Province to ancient meteorite impacts and the rise of oxygen in the atmosphere, there is much to be seen in the Precambrian bedrock of Minnesota. This presentation will explore the varied geologic environments and events that have shaped the Precambrian terranes underlying much of Minnesota.

Biography: Eric Nowariak is currently a Precambrian Geologist with the Minnesota Geological Survey, focused on geologic mapping and critical mineral related studies. Eric received a B.S. (2013) in Geology from Winona State University and a M.S. (2016) in Geology from the University of Missouri – Columbia, where he focused on metamorphic petrology, structural geology, and tectonics of Precambrian rocks in Southeastern Wyoming. Prior to joining the MGS in 2021, Eric was a consulting geologist in the mineral exploration industry.

Summary: Josh Kirk and Jill Mickelson, two professional engineers from local environmental consulting firm Braun Intertec, will talk about the geology of bridge construction. This presentation will address not only how bridges are constructed, but how they interact with their environment to provide for a safe and stable structure. We will identify how the geotechnical investigation provides key information that guides designers on how to appropriately support their structures, and evaluate how different geologic settings can lead to different bridge foundation approaches. We will also discuss how some of the unique geological settings in Minnesota lead to the need for creative construction approaches as designers and contractors deal with sinkholes, bogs, artesian conditions, bluff stability, river flooding and the like. We will explore some of the related environmental issues that can arise during bridge construction such as dealing with contamination as well as protecting unique and endangered resources. We will share how a strong knowledge of the interactions between the bridge system and the geology of the building site influences a project’s chances at successful completion.

Biography: Jill Mickelson has more than 19 years of experience in the environmental field, providing professional consulting services to private and municipal clients, including the St. Paul Port Authority, City of Waite Park, City of Rochester and the Minnesota Department of Transportation. As a principal engineer, Jill’s experience includes managing environmental construction management, preparing plans and construction documents for demolition and brownfield redevelopment projects, conducting compliance assessments and regulatory permitting, providing coordination of field operations, supervising due diligence Phase I and II Environmental Site Assessment (ESA) and Environmental Assessment Worksheets (EAW), and evaluating remediation strategies for soil and groundwater cleanup.