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Geologic Mapping Forum 2023/2024 Abstracts
(Minnesota Geological Survey, 2024) Thorleifson, Harvey
The Geologic Mapping Forum (GMF) in Minneapolis in 2018 and 2019 was attended by ~100 geological map authors, program managers and allied professionals from geological surveys and associated agencies, who met to discuss the status and future of geological mapping in the USA. Due to the coronavirus pandemic, the 2020 Geologic Mapping Forum planned for April 7th to 9th, 2020, was not held. It therefore was decided that GMF Online would be held as meetings of about two hours duration on Thursdays at Noon Central, about once per month, from early autumn until spring, in 2020/2021, 2021/2022, 2022/2023, and 2023/2024. A similar format is planned for 2024/2025. For the 2025/2026 GMF, plans are being developed for a September 2025 in-person meeting in Minneapolis, similar to the 2018 and 2019 meetings. Online meetings would follow, that winter. Early plans for 2026/2027 call for the in-person meeting to be in Denver. The intended GMF audience is geological map authors and program managers, and the focus in geology rather than funding or GIS. Optional abstracts for the 20-minute invited talks were requested, and are presented here.
Geologic Investigation for Portion of the Twin Cities Metropolitan Area: Quaternary/Bedrock Hydraulic Conductivity and Groundwater Chemistry
(Minnesota Geological Survey, 2010-11-24) Tipping, Robert G; Runkel, Anthony C; Gonzalez, Christopher M
This report summarizes work performed by the Minnesota Geological Survey (MGS) in partial fulfillment of work as described under contract 091037 between the University of Minnesota and the Metropolitan Council. The goal of this investigation was to provide datasets that would assist the Metropolitan Council with regional ground water planning. Specifically, hydraulic conductivity data for both unconsolidated and bedrock materials, along with historic ground water chemical and isotopic data were assembled into spatial databases that can be used in a geographic information systems (GIS) format. Wherever possible, depth of the sampled or tested material was included along with location information, so the three-dimensional distribution of these data could be queried and compared to ongoing Metropolitan Council planning projects. For hydraulic conductivity data, the focus was on glacial-related Quaternary deposits, because these are the data most lacking for current ground-water modeling investigations. Hydrostratigraphic attributes of fine-grained materials were evaluated based on a comparison of measured values with texture, depth, and a literature review of other midcontinent tills. For water chemistry, the goal was to display the distribution of chemical types (hydrochemical facies) as a means to illustrate possible ground-water flowpaths. A sample acquisition date was included so the database could also be used to assess changes in chemical composition with time. For both hydraulic conductivity data and water chemistry, attributes were also assigned to a regional dataset of regularly spaced grid points to facilitate importing the data into groundwater modeling programs. The individual point data geodatabase (PointData.mdb) provides access to hydraulic conductivity and chemical data for a specific site. Because much of the site information on geologic setting comes from different consultant's reports, there is a lack of consistency in lithologic and stratigraphic attributes. In this way, PointData.mdb is best suited as a "what's in my neighborhood" type of dataset rather than for rigorous regional spatial analysis of hydraulic conductivity data. The grid design of regional summary data geodatabase (RegionalData.gdb) is meant to provide the means to readily import and adjust hydraulic conductivity and chemical data in ground water flow models, or for use as an additional layer for three-dimensional evaluation of model results. Use of regional summary data in these settings can aid in refining conceptual models of ground-water flow.
Geologic Mapping Forum 22/23 Abstracts
(Minnesota Geological Survey, 2023) Thorleifson, Harvey
The Geologic Mapping Forum in Minneapolis in 2018 and 2019 was attended by ~100 geologic map authors, program managers, and allied professionals from geological surveys and associated agencies, who met to discuss the status and future of geological mapping in the USA. Due to the coronavirus pandemic, the 2020 Geologic Mapping Forum planned for April 7th to 9th, 2020, was not held. It therefore was decided that GMF Online would be held as meetings of about two hours duration on Thursdays at Noon Central, about once per month, from early autumn until spring, in 2020/2021, and again in 2021/2022, and in 2022/2023. The intended GMF audience is geologic map authors and program managers, and the focus again was on geology rather than funding or GIS. Optional abstracts for the 20-minute invited talks were requested, and are presented here.
GEOPHYSICAL AND PETROLOGIC INVESTIGATIONS OF INVERSELY CORRELATED AEROMAGNETIC AND BOUGUER GRAVITY ANOMALIES WITHIN PRECAMBRIAN GNEISS TERRANE NEAR GARVIN, SOUTHWESTERN MINNESOTA
(Minnesota Geological Survey, 2023) Southwick, David L; Chandler, V.W.; McSwiggen, Peter L
Geophysical models and petrologic inferences presented here are consistent with a buried gabbroic to noritic intrusion as the principal source of two geographically coincident, kilometer-scale, inversely correlated gravity and magnetic anomalies (the Garvin anomalies) located within Archean continental crust near the present-day southern margin of the Superior Craton in Minnesota. Two-dimensional profiles modeled from the total magnetic anomaly, reduced to pole, and the Bouguer gravity anomaly, upward-continued to 2 kilometers, are fit to geologically reasonable distributions of source rocks that have density and magnetic susceptibility values within the ranges reported for gabbro or norite intrusions.
The Owen-Norwood Survey of 1847-1850 - THe first geological survey of the northeast Minnesota region - and its context in the evolution of geological science
(Minnesota Geological Survey, 2022) Green, John C
The Owen/Norwood geological survey of Minnesota’s North Shore of Lake Superior – the first geological survey in this area - was carried out in a dynamic period of both American socioeconomic history and the growth of the science of geology. It was begun in 1847, as the U. S. Government had charged David Dale Owen with surveying most of WI, MN, IA and part of NB. Owen was assisted in much of this huge area by other notable geologists; Joseph G. Norwood examined the North Shore and adjacent areas. This was part of the “manifest destiny” of Euroamerican occupation of North America. Access to the interior of the Old Northwest was facilitated by successive treaties with Native Americans (mostly Chippewa), in which lands in MI and WI were ceded in 1836, 1837, and 1842 to the U. S. Government. The U. S. wanted to determine what the mineral potential might be for an anticipated land cession in the wilderness of northern MN Territory.
From Compass to Drone: The Evolving Role of Magnetics in Mapping the Geology and Ore Deposits Of the Lake Superior Region: 1830-2022
(Minnesota Geological Survey, 2022) Hinze, William J
The Lake Superior region, the “Birthplace of North American Precambrian Geology,” is noted for its world-class mineral resources, especially its native copper and iron ore deposits, and its classic bedrock of Archean and Proterozoic orogenic belts and the exposures of rocks of the Midcontinent Rift System. The magnetic method of mapping the region’s ore deposits and bedrock geology has been used for nearly two centuries because of limitations in the exposure of the Precambrian bedrock in the region. For the first century magnetic mapping was directed primarily at the identification of regions favorable for iron and copper ore deposits using simple magnetic needle instrumentation. Initially instrumentation was limited to the use of the dial (sun) compass and used mainly for exploration of hard, magnetite-rich iron ore deposits. With the introduction of the dip needle, a counterbalanced magnetic needle oscillating vertically in the magnetic meridian, to the Lake Superior region likely in 1865 by T.B. Brooks, magnetic mapping was no longer restricted to the difficult to interpret magnetic field angular variations.
Compilation Geologic Model for Redeye River Watershed: A Pilot Project
(Minnesota Geological Survey, 2022-07) Steenberg, Julia R; Retzler, Andrew J; Hamilton, Jacqueline D; Francis, Sarah W
This report is a summary of year one of a two-year pilot project conducted by the Minnesota Geological Survey for the Minnesota Department of Health Groundwater Restoration and Protection Strategies (GRAPS) program designed to support watershed planning efforts in the Redeye River Watershed. Our goal was to provide a compilation of both surface and subsurface geologic data within selected Board of Water and Soil Resources One Watershed One Plan boundaries in a format suitable for both modelers and the general public. Seamless geologic products provided within the watershed are based on a compilation of previously published MGS maps along with new mapping where necessary. Compilation methods and limitations associated with the subsurface modeling processes are described in the report. These products were transferred into web-based 3D models so they could be readily visualized and used outside of a GIS environment by water planners, other state agencies involved in the GRAPS process, and the public. The 3D model is available online at https://arcg.is/15Gnz02.
Compilation Geologic Model for Missouri River Watershed: A Pilot Project
(Minnesota Geological Survey, 2022-07) Steenberg, Julia R; Retzler, Andrew J; Hamilton, Jacqueline D; Francis, Sarah W
This report is a summary of year one of a two-year pilot project conducted by the Minnesota Geological Survey for the Minnesota Department of Health Groundwater Restoration and Protection Strategies (GRAPS) program designed to support watershed planning efforts in the Missouri River Watershed. Our goal was to provide a compilation of both surface and subsurface geologic data within selected Board of Water and Soil Resources One Watershed One Plan boundaries in a format suitable for both modelers and the general public. Seamless geologic products provided within the watershed are based on a compilation of previously published MGS maps along with new mapping where necessary. Compilation methods and limitations associated with the subsurface modeling processes are described in the report. These products were transferred into web-based 3D models so they could be readily visualized and used outside of a GIS environment by water planners, other state agencies involved in the GRAPS process, and the public. The 3D model is available online at https://arcg.is/1iimH50.
Compilation Geologic Model for Cannon River Watershed: A Pilot Project
(Minnesota Geological Survey, 2022-07) Steenberg, Julia R; Retzler, Andrew J; Hamilton, Jacqueline D; Francis, Sarah W
This report is a summary of year one of a two-year pilot project conducted by the Minnesota Geological Survey for the Minnesota Department of Health Groundwater Restoration and Protection Strategies (GRAPS) program designed to support watershed planning efforts in the Cannon River Watershed. Our goal was to provide a compilation of both surface and subsurface geologic data within selected Board of Water and Soil Resources One Watershed One Plan boundaries in a format suitable for both modelers and the general public. Seamless geologic products provided within the watershed are based on a compilation of previously published MGS maps along with new mapping where necessary. Compilation methods and limitations associated with the subsurface modeling processes are described in the report. These products were transferred into web-based 3D models so they could be readily visualized and used outside of a GIS environment by water planners, other state agencies involved in the GRAPS process, and the public. The 3D model is available online at https://arcg.is/09OS1L0.
OFR22-01, Assessment of preservation needs and long-range plan for geologic collections and data in Minnesota; a report prepared in fulfillment of National Geological and Geophysical Data Preservation Program Award Number 07HQGR0126
(Minnesota Geological Survey, 2009) Thorleifson, L Harvey
According to the National Geological and Geophysical Data Preservation Program (NGGDPP) web site, section 351 of the Energy Policy Act of 2005 directs the Secretary of the Department of the Interior (DOI), through the Director of the U.S. Geological Survey (USGS), to carry out a National Geological and Geophysical Data Preservation Program. The Implementation Plan for the NGGDPP, submitted to Congress in August 2006, outlines the vision and purpose of the program and makes recommendations for its implementation. One of the early action items in the implementation plan is for USGS to begin interactions with State Geological Surveys and other DOI agencies that maintain geological and geophysical data and samples to address their preservation and data rescue needs. As the first step in this process, USGS requested that each state provide an assessment of current collection resources and data preservation needs, and thus provide a summary of the collections held, supported, or used by state geological surveys.
OFR22-03, Geologic Mapping Forum 2018 summary
(Minnesota Geological Survey, 2022) Thorleifson, L Harvey
At the Geologic Mapping Forum in Minneapolis from March 27th to 29th, 2018, ~100 geological map authors, program managers and allied professionals from geological surveys and allied agencies met to discuss the status and future of geologic mapping in the USA. The meeting was hosted by Minnesota Geological Survey on the University of Minnesota campus. The meeting was held near the Mississippi River, at the Humphrey School of Public Affairs on the West Bank campus, in the Humphrey School Conference Center at 301 19th Avenue South, Minneapolis, MN 55455. Unless they had been invited to speak in a plenary, all participants were urged to present a 15-minute talk in a concurrent session or a poster. Plenary, concurrent session, and poster presenters were asked to submit a 1 to 2-page abstract. The meeting commenced with registration and a reception at the hotel with light food and drinks on Monday from 5 to 7 PM, followed by conference sessions from 8:30 AM Tuesday until 4:30 PM Thursday.
OFR22-02, Geologic Mapping Forum 21/22 Abstracts
(Minnesota Geological Survey, 2022) Thorleifson, L Harvey
Due to the coronavirus pandemic, the Geologic Mapping Forum was again held online in 2021/2022, as monthly meetings from September 2021 to April 2022. As many as 158 geological map authors, program managers and allied professionals from geological surveys and associated agencies attended, to discuss the status and future of geologic mapping in the USA and neighboring countries. The meetings were hosted by the Minnesota Geological Survey of the University of Minnesota. Participants were invited to present a 20-minute minute talk, and were given the option to submit a 1 to 2-page abstract published in this Open File.
OFR21-08, Compilation Geologic Model for St. Louis River Watershed: A Pilot Project
(Minnesota Geological Survey, 2021-08) Steenberg, Julia R; Retzler, Andrew J; Wagner, Kaleb G; Hamilton, Jacqueline D
This report is a summary of year one of a two-year pilot project conducted by the Minnesota Geological Survey for the Minnesota Department of Health Groundwater Restoration and Protection Strategies (GRAPS) program designed to support watershed planning efforts in the St. Louis River Watershed. Our goal was to provide a compilation of both surface and subsurface geologic data within selected Board of Water and Soil Resources One Watershed One Plan boundaries in a format suitable for both modelers and the general public. Seamless geologic products provided within the watershed are based on a compilation of previously published MGS maps along with new mapping where necessary. Compilation methods and limitations associated with the subsurface modeling processes are described in the report. These products were transferred into web-based 3D models so they could be readily visualized and used outside of a GIS environment by water planners, other state agencies involved in the GRAPS process, and the public. The 3D model is available online at https://arcg.is/1mbDPC.
OFR21-03, Compilation Geologic Model for Zumbro River Watershed: A Pilot Project
(Minnesota Geological Survey, 2021-06) Steenberg, Julia; McDonald, Jennifer; Retzler, Andrew; Hamilton, Jacqueline
This report is a summary of year one of a two-year pilot project between the Minnesota Geological Survey and the Minnesota Department of Health Groundwater Restoration and Protection Strategies (GRAPS) program designed to support watershed planning efforts in the Zumbro River Watershed. Our goal was to provide a compilation of both surface and subsurface geologic data within selected Board of Water and Soil Resources One Watershed One Plan boundaries in a format suitable for both modelers and the general public. Seamless geologic products provided within the watershed are based on a compilation of previously published MGS maps along with new mapping where necessary. Compilation methods and limitations associated with the subsurface modeling processes are described in the report. These products were transferred into web-based 3D models so they could be readily visualized and used outside of a GIS environment by water planners, other state agencies involved in the GRAPS process, and the public. The 3D model is available online at https://arcg.is/fevGS.
OFR21-01, Geologic Mapping Forum 20/21 Abstracts
(Minnesota Geological Survey, 2021) Thorleifson, L Harvey
Due to the coronavirus pandemic, the Geologic Mapping Forum for 2020 and 2021 was held online as monthly meetings from October 2020 to April 2021. As many as 140 geological map authors, program managers and allied professionals from geological surveys and associated agencies attended, to discuss the status and future of geologic mapping in the USA and neighboring countries. The meeting was hosted by the Minnesota Geological Survey of the University of Minnesota. Participants were invited to present a 20-minute minute talk, and were given the option to submit a 1 to 2-page abstract published in this Open File.
OFR21-02, Pilot Multi-county Modeling Synthesis For Bonanza Valley Groundwater Management Area
(Minnesota Geological Survey, 2019) Tipping, Robert G
This report reviews current subsurface unconsolidated sediment modeling methods at MGS to address how model application to regional investigations can be improved in several fundamental ways: 1.) reduce errors and redundancy in final subsurface models that are artifacts of the modeling process itself, including linearity along cross-section lines in both elevation and map unit extent, unintended gaps in map units between cross sections, and lithostratigraphic formation subdivision to accommodate sand bodies within formations ; 2.) quantify uncertainty in modeling subsurface sand and gravel; and 3.) provide a work plan and method for subsurface models to remain current within shorter time frames as new data become available.
OFR20-01, Minnesota Data Preservation Report for 2019/2020: Updated Data Inventory, Preservation of Pillsbury Hall Rock Collections and Documentation, Assembly of Mineral Potential Related Information
(Minnesota Geological Survey, 2020) Thorleifson, L Harvey
Minnesota Geological Survey (MGS) activity is focused primarily on recommendations of Legislative panels that indicate that statewide coverage of layered County Geologic Atlases will be needed to support management of water resources, while concurrently being needed for applications such as mineral resources, engineering, hazards, and research. All MGS activity is reliant on geological specimens, as well as geological, geophysical, and geochemical data. The MGS long-term data preservation plan prepared in 2009 identified the highest priorities in relation to applications such as groundwater management and mineral resource assessment. Included were: 1) reprocessing of the aeromagnetic database; 2) enhancement of location precision for gravity stations; 3) vertical georeferencing of the rock property database; 4) cataloging and georeferencing of rocks and thin sections stored at the building MGS occupied from 1983 to 2015; 5) standardized formats for existing databases; and 6) scan and web enable all publications. More recently, a need was recognized for: 7) scanning, digitizing, and enhanced cataloging of borehole geophysical records, 8) comprehensive regional geophysical survey rescue, 9) enhancements to the cuttings collection and database. Objectives 1, 2, and 3 were completed with State of Minnesota support. Objective 4 was completed with multiple years of NGGDPP support. Objective 5 is ongoing. Objective 6 was completed with University of Minnesota Library support. Objective 7 was completed for gamma logs with our 2015 NGGDPP grant, and was completed for all borehole geophysical logs due to 2017 NGGDPP support. Geophysical survey rescue will remain unfulfilled due to staff availability constraints. Work on cuttings will be carried out due to NGGDPP support during 2020/2021.
OFR19-02, Geochemical Analysis of Till From Minnesota Drill Cores
(Minnesota Geological Survey, 2019) Thorleifson, L.H.; Conrad, D.R.; Staley, A.E.
Compositional analysis of texture and very coarse sand lithology have been used to support characterization of till properties, and interpretation of correlation, process, and provenance. In 2007, results were released for more thorough compositional analyses of near-surface till samples collected statewide. Quaternary stratigraphic efforts are now focused on information needed to support regional groundwater management. To support that effort, till from selected rotasonic cores extending to tens of meters depth were submitted in 2018 and 2019 for geochemical analysis following the method used for part of the 2007 study - four-acid leach of air dry <63 micron fraction followed by ICP. Examples of elements that correlated to provenance are As in shale-rich till, Ca in carbonate-rich till, Na in shield-derived till, and Fe in Lake Superior-derived till. All data are here provided as a reference.
OFR18-03, Core Descriptions, Borehole Geophysics, and Unit Interpretations in Support of Phase I and II USGS Hydrologic Properties of Till Investigation
(Minnesota Geological Survey, 2018) Staley, Amie E; Wagner, Kaleb; Nguyen, Maurice; Tipping, Robert
This report summarizes the contributions of the Minnesota Geological Survey (MGS) to a three-year study conducted in two phases – Environmental and Natural Resources Trust Fund (ENRTF), M.L. 2014, Chp. 226, Sec. 2, Subd. 03h, and ENTRF, M.L. 2016, Chp. 186, Sec. 2, Subd. 04h, led by the United States Geological Survey (USGS) Minnesota Water Science Center, which seeks to further knowledge on the sources and rates of recharge to confined aquifers set within buried-valley sequences in Minnesota. Six cores (including one collected for a previous study) of unconsolidated Quaternary deposits were extracted from known confined glacial aquifer settings, in four regions across Minnesota, in order to target variability in the material properties of the aquitards that confine them.
OFR19-1, Geologic Mapping Forum 2019 Abstracts
(Minnesota Geological Survey, 2019) Thorleifson, L Harvey
At the Geologic Mapping Forum in Minneapolis from April 10th to 12th, 2019, ~100 geological map authors, program managers and allied professionals from geological surveys and associated agencies met to discuss the status and future of geologic mapping in the USA and neighboring countries. The meeting was hosted by the Minnesota Geological Survey on the University of Minnesota campus. The meeting was held at the Humphrey School of Public Affairs on the West Bank campus, in the Humphrey School Conference Center at 301 19th Avenue South, Minneapolis, MN 55455. Participants were invited to present a 30-minute plenary or 15-minute talk, or a poster, and submitted a 1 to 2-page abstract published in this Open File. The meeting opened with registration and a reception on Tuesday evening followed by conference sessions beginning at 8:30 AM Wednesday and ending 2:30 PM Friday. Regional organization business meetings followed on Friday afternoon and Saturday.