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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

At least 793 records · Page 44Linked to original sources
USGS2026

Colonization of southern flying squirrels (Glaucomys volans) to urban Nebraska: Range expansion or human assisted translocation?

Southern flying squirrels ( Glaucomys volans; Linnaeus 1758) were first observed in Lincoln, Nebraska, in 2018, 80 km north of their described range. Given that southern flying squirrels are a species of concern within Nebraska, determining the origin of this new population (natural expansion or pet-trade) garnered interest from state biologists. Further, the recent colonization of Lincoln by southern flying squirrels presents a unique opportunity to investigate the genetic implications of a founding event on a small arboreal mammal. The Lincoln population had genetic characteristics suggestive of a single-event colonization with fewer rare alleles and lower genetic diversity than potential source populations and a high genetic variation between populations. Sample size and absence of other geographically close populations in our data set make it difficult to ascertain the origin of the Lincoln population. Based on shared co-ancestry and membership assignment clustering algorithms, the Lincoln population had greater genetic associations with an individual sampled from the native south-eastern Nebraska population relative to other studied locations, suggesting that Lincoln was colonized by a native population.

Nebraska↗
USGS2026

Waves, watersheds, and sediment in a coral reef embayment: Towards parsimonious models of accumulation and composition

High sedimentation rates can damage coral reef ecosystems. Sedimentation rates are controlled by both sediment loads from watersheds and resuspension by waves and associated circulation patterns, but the outcomes are system specific and difficult to predict. The percent terrigenous (non-organic and non-carbonaceous) material in sediment is also often used as an indicator of watershed influence, but its dynamics are poorly understood. Sediment accumulation rates, particle size, and percent terrigenous were monitored quasi-monthly for one year (March 2014-April 2015) at nine sites in a coral reef-fringed embayment in American Samoa, where an aggregate quarry had increased sediment loads to the coast but mitigation reduced loads during the monitored period. Gross and net sediment accumulation rates were measured using sediment traps and SedPods (pods), respectively. Gross accumulation rates exceeded thresholds for impacts on coral health during at least one collection period at most sites, with more exceedances on the northern reef where water residence times and sediment availability are higher and corals show signs of sediment stress. Percent terrigenous of coarse sediment was higher in the traps and pods compared with the surrounding benthic sediment, indicating that some of the terrigenous sediment was advected through the bay without accumulating on the reef. The 95th percentile of hourly wave energy density ( E 95 ) taken from a global wave model (WaveWatch 3) was the best predictor of gross accumulation rates of both total and carbonate sediment in a log-log regression at most ( n = 6) sites ( R 2 range 0.72-0.92), indicating a strong role of resuspension of benthic sediment. Gross accumulation rates of terrigenous sediment were not correlated with E 95 and only correlated with SSY at the site nearest the stream mouth, indicating that most terrigenous sediment was not from resuspended benthic material but rather from a consistent watershed source. Percent terrigenous decreased with increasing wave energy due to high accumulation rates of carbonates during periods of high wave energy. Detection of the impact of sediment mitigation at the quarry on sediment accumulation was complicated by low wave energy in the period following mitigation. The use of gross accumulation rates and percent terrigenous as indicators of the magnitude and sources of sediment accumulation over time needs to account for wave-induced resuspension, which can be modelled with a simple power function using inputs from a global wave model.

Estuarine, Coastal and Shelf Science↗
USGS2026

Rearing method has limited effect on post-release movement of reintroduced age-0 Lake Sturgeon

Overfishing, habitat loss, and pollution caused the extirpation of Lake Sturgeon ( Acipenser fulvescens ) throughout much of the Great Lakes. A Lake Sturgeon reintroduction program using two rearing strategies began in 2018 in the Maumee River, a tributary of Lake Erie. We assessed the movement of streamside or traditionally reared age-0 Lake Sturgeon using acoustic telemetry to determine if rearing strategy affected river residency, movement, and the habitat area used. Tagged sturgeon generally left the Maumee River for Lake Erie on average 3–47 days after stocking and spent most of their time in the western basin of Lake Erie. The majority of sturgeon moved through nearshore areas along the south shore of Lake Erie. While we found no differences in post-stocking movements or habitat area used between the two rearing strategies, understanding how older life stages respond to rearing strategy is needed. Adding upstream stocking sites, using source water to raise eggs or larvae if excessive straying becomes evident, and increased acoustic receiver coverage are options to facilitate and evaluate successful recovery of Lake Sturgeon.

Ohio↗
USGS2026

Biochar modulates the dynamics of legacy nutrients in enhancing soil health and crop productivity

Most major crops in agricultural soils exhibit relatively low nutrient use efficiency for nitrogen (N), phosphorus (P), and potassium (K), often necessitating supplemental nutrient inputs to achieve sustainable yields. Furthermore, the increasing use of biowastes such as compost, manure, and biosolids, which frequently have nutrient ratios that do not match crop requirements, has contributed to excessive nutrient inputs and subsequent accumulation in soils. This situation has been further exacerbated by intensive farming practices involving multiple cropping cycles per season. Overuse of nutrients causes them to accumulate in the soil, creating a legacy nutrient pool. The application of biochar as soil amendment is considered a potential strategy to control legacy nutrients dynamics. The current review inspects the possible value of biochar in modulating legacy nutrient reserves in the soil, thereby increasing the bioavailability of nutrients and improving crop yield. This review discusses the search scope and synthesis approaches for the bibliometric methodological component through rigorous screening process (Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA)), focusing on journal articles published in last 20 years that specifically address legacy nutrient management. The significance of the economic and environmental effects of legacy nutrients and the insufficient knowledge of how biochar application influences nutrient dynamics in soil highlight the necessity for additional research to address current gaps.

Land↗
USGS2026

Tracking toxins: A pilot investigation of cyanotoxins in north-central Tennessee’s surface waters and wells

Cyanobacterial toxins (cyanotoxins) threaten aquatic ecosystems and human health, yet the factors influencing their production and distribution in freshwater remain unclear. In north-central Tennessee, nutrient-rich runoff from agricultural and urban areas, combined with a karst landscape that supports drinking and recreational water use, heightens the need to understand cyanotoxin behavior. To examine cyanotoxin patterns, the U.S. Geological Survey and the Tennessee Department of Environment and Conservation monitored 18 sites, including two wells under the influence of surface water, every two weeks from September 2022 to November 2024. At least one cyanotoxin was detected at all sites, with the highest concentrations in deep reservoirs and lower levels in shallow systems. Most detections occurred during summer and fall, aligning with high temperatures and rapid-onset drought. Statistical analysis indicated that increased specific conductivity and pH raised the likelihood of detecting total microcystin, likely resulting from drought conditions and nutrient-laden runoff. Additionally, dissolved microcystin showed an inverse relationship with Cumberland River water levels, and principal component analysis showed that Secchi depth, chlorophyll a, pH, temperature, and conductivity explained most water quality variability. These results help increase understanding of cyanotoxin distribution and associated water quality conditions during detections to guide future freshwater cyanotoxin monitoring studies.

Tennessee↗
USGS2026

High-resolution transboundary vegetation community maps of the Sonoran and Mojave Desert ecoregion to support critical landscape conservation planning and habitat management needs

We produced a 30-m resolution binational land cover map of Bird Conservation Region 33 (BCR 33) for the U.S. North American Bird Conservation Initiative. The region covers large portions of the Sonoran and Mojave Deserts. The map can support the U.S. Fish and Wildlife Service (FWS) Migratory Bird Program’s recovery planning efforts and constitutes the first known binational land cover dataset spanning sections of the United States–Mexico border and using a consistent classification system for both countries. The mapped region includes 152 distinct land cover classes, covering a total area of 38,421,453 ha (148,345 mi 2 ), of which 13,148,345 ha (52,706 mi 2 ) are located in Mexico and 24,770,640 ha (95,639 mi 2 ) in the United States. We primarily used Landsat 8 (OLI) imagery, supplemented by limited ground surveys from two field campaigns, drone-based aerial data, and existing vegetation classification frameworks from both countries. The classification applied a data-fusion approach integrating 30-m Landsat 8 imagery, decadal phenology metrics from vegetation indices, and a random forest model trained mainly with datasets from a comprehensive national mapping project from the U.S. Geological Survey (USGS) GAP Analysis Project (GAP) and federal wildland fire agencies’ Landscape Fire and Resource Management Planning Tools (LANDFIRE) (GAP/LANDFIRE) [United States side] and the National Institute of Statistics and Geography (INEGI) [Mexico side] as well as land cover maps and opportunistic open-access and field observations. Mapping of the full BCR 33 region was carried out in two phases: 1) Phase I, the prototype map, covered a smaller portion of the transboundary area and identified 31 land cover classes, and 2) Phase II, the full BCR 33 map (refer to Figure 1), which resulted in 152 land cover classes. Using a Random Forest classifier, we achieved an overall prediction accuracy of 92% for the Phase I map and 87% for the Phase II full region map. This slight decrease can be attributed to working on a larger, more complex area with a greater number of land cover classes. No formal validation was conducted, aside from using a subset of the collected field observations and training data to assess model performance during and after training. The training sites were further verified using Google Earth (Google, 2026) imagery. Two undergraduate students who worked for over a year visually inspected imagery and open access public images to confirm each training site during model training using in-house developed, online, visual tools. A portion of this field training data was reserved for model validation, and the corresponding results are to be presented in later sections. The project developed an end-to-end, medium- and fine-resolution remote sensing–based data fusion mapping approach. This effort produced a map (Nagler et al., 2025) and the online tools to support a dynamic, live, online map for visualizing the transboundary vegetation communities in BCR 33. The toolset is currently hosted by the University of Arizona (UofA) Vegetation Index and Phenology (VIP) Lab to support FWS partners (https://vip.arizona.edu/viplab_data_explorer?LCM_BCR33). The online map is designed to allow rapid updates using new training, validation, or correction data, making it dynamic and maintainable. The approach we took established a framework for rapid updating and correction of land cover maps, as the model can be quickly retrained with new field observations, updated training data, or other sources. This enables dynamic mapping and change detection of the region’s vegetation. This framework is an advance in data fusion and crowdsourced mapping of complex, vulnerable regions, providing support to regional stakeholders and the wider user community. This transboundary map can inform the protection, conservation, and restoration of vegetation, habitat, and ecosystems, particularly for threatened and endangered species across the two nations using consistent and harmonized binational mapping systems. Beyond supporting land management decisions and stakeholders in the transboundary desert ecoregions, this BCR 33 mapping effort establishes a foundation for future rapid, low-cost, cross-border land cover mapping that can benefit and advance ecosystem management.

Arizona, Baja California, California, Nevada, Sina↗
USGS2026

Ecology of reintroduced Rocky Mountain bighorn sheep in Dinosaur National Monument

Translocations have been widely used to restore and conserve bighorn sheep ( Ovis canadensis ) populations in North America. Some translocations have been successful, but many populations remain small and genetically isolated. Population structure can influence the viability and long-term success of reintroductions. Social ungulates often function as interconnected subpopulations (metapopulations); however, few studies evaluate subpopulation sizes, connectivity, and genetic diversity within metapopulations. To address this gap, we conducted a comprehensive study of a reintroduced Rocky Mountain bighorn sheep ( Ovis canadensis canadensis ) population in Dinosaur National Monument in Colorado and Utah, USA, between 2006–2020. We analyzed global positioning system (GPS) radio-collar data, genetic samples, and results of health testing to evaluate abundance, distribution, genetic structure and diversity, habitat use, movement and connectivity, and presence of or exposure to respiratory pathogens. We integrated these analyses to evaluate the outcomes of a reintroduction effort that began in 1952, over 70 years ago, and to inform management decisions in Dinosaur National Monument. We also provide a framework for evaluating metapopulation processes, including a non-invasive approach that links genetic structure with Bayesian spatial capture-recapture analyses to estimate subpopulation sizes. Despite models indicating continuous suitable habitat, we found a spatially structured population with at least 4 subpopulations with constrained connectivity. Evidence from step selection and density analyses suggested that movement among subpopulations may be limited by semi-permeable barriers including rivers and human disturbance, which could contribute to maintenance of spatial structure over time. In 2006, antibody to Mycoplasma ovipneumoniae was detected in all geographically and genetically distinct subpopulations. Widespread clinical signs of disease and a confirmed exposure to M. ovipneumoniae in 2019 indicate a long-term disease challenge. Proximity to domestic sheep creates repeated opportunities for introduction of new M. ovipneumoniae strains. We estimated abundance in 2019 at 109 (95% CrI = 87–133), composed of subpopulations ranging from 18–39 animals (95% CrIs from 11–50). Genetic diversity was relatively high compared to other reintroduced and native Rocky Mountain bighorn sheep populations, which is likely a consequence of multiple translocations from different sources. Three of 4 subpopulation centers generally aligned with the locations of original translocation release sites. Persistence in the presence of pathogens may be facilitated by metapopulation structure and moderately high genetic diversity. Conversely, metapopulation structure can also facilitate pathogen persistence. Our approach offers a path to advance understanding of the population ecology of reintroduced bighorn sheep and can inform effective conservation and management of their populations.

Colorado, Wyoming↗
USGS2026

Modeling the seasonality of wind-driven hydrocarbon waves in Titan’s polar lakes

Titan, the only body in the solar system aside from Earth with standing liquids on its surface, has polar hydrocarbon lakes and seas. As Titan’s atmosphere generates light winds, there should be waves on the surface of these lakes and seas, yet, direct wave observations are scant. We introduce and use PlanetWaves , an open source 4D spectral wave model, to study Titan’s waves and create seasonal maps of wave shape and propagation on Ontario Lacus and Ligeia Mare. Titan’s modeled waves grow up to 30 times larger than terrestrial waves for the same wind speed, are seasonally present and are largest in the spring and summer when winds are strongest. Average daily winds almost never exceed the wave generation threshold of 0.5–0.7 m/s. Average storm winds (∼1.5 m/s) generate waves 15–48 cm in height with a period ranging 6–10.5 s while maximum storm winds (∼4 m/s) generate waves 2.7–3.2 m in height with a period up to 32 s. Titan’s waves become fetch-independent at ∼40 km for average storm winds occurring ∼1% of a Titan year and ∼100 kilometers for maximum storm winds occurring 2-3 times per Titan decade. On Ontario Lacus, storm winds blow nearly parallel to the eastern shore, potentially driving wave modification of the smooth eastern shoreline. On Ligeia Mare, waves rarely propagate toward a hypothesized wave modified shoreline suggesting that another process, such as tectonics, may contribute to a straight shoreline morphology.

JGR Planets↗
USGS2026

Indicators of mercury concentration in Lake Trout: Can fish location and appearance provide information to anglers to reduce their exposure?

Objective People are exposed to mercury (Hg) through the consumption of fish. State and federal governments provide broad, often-generalized food safety guidance to reduce exposure; however, numerous rural fishing areas lack testing and location- or species-specific guidance. The aim of this study was to provide tangible, visible, or easily measured characteristics of Lake Trout Salvelinus namaycush that could convey information on Hg exposure to people harvesting and consuming fish where no location-specific guidance exists. Methods We investigated potential indicators of Lake Trout total Hg (THg) concentrations in muscle across 10 lakes in Alaska's national parks. Potential indicators, including lake, lake zone (i.e., littoral, pelagic, profundal), fish length, head size, body condition, and general appearance, were evaluated by competing linear mixed-effects models. Results Lake Trout THg concentrations ranged widely from 22 to 1,306 ng/g wet weight. Much of the variation (48%) in THg concentrations was attributed to differences among individual lakes, but the interaction of the fish's lake zone, body length, and head size accounted for an additional 21%. Predicted THg concentrations increased with Lake Trout length and head : body proportion, but the rate of THg concentration increase with length varied by head : body proportion and lake zone. Conclusions Given the overwhelming evidence of high lake-to-lake variability in Lake Trout THg concentrations, we find support for use of lake-specific guidance when data are available. When lake-specific THg concentrations are not available, the best potential way to reduce exposure is to harvest and consume Lake Trout with mean predicted THg concentrations that are within state and federal safe consumption guidelines. This included Lake Trout from surface waters (i.e., pelagic or littoral zone) that are ≤70 cm in length; if harvesting fish from deep waters (i.e., profundal zone), lower THg concentrations were found in Lake Trout with heads ≤25% of their body length. The indicators—lake zone, length, and head size—of Lake Trout THg concentrations can provide harvesters with additional information in the absence of data for specific lakes.

Alaska↗
USGS2026

Critical minerals memory match game

An educational information packet about the 2025 List of Critical Minerals, which includes a memory match game about select critical minerals and how they are used.

General Information Product↗
USGS2026

Time-to-depth conversion of seismic-reflection data from eastern Lake Superior and implications for the eastern arm of the Midcontinent Rift

Seismic-reflection data were acquired in the mid 1980s along several lines across eastern Lake Superior by industry and the Great Lakes International Multidisciplinary Program on Crustal Evolution (GLIMPCE) (Fig. 1). The lines form part of a larger network of crossing lines over the entire lake, which can be used to develop three-dimensional geologic models of the Mesoproterozoic Midcontinent Rift that lies below. To better interpret these lines, we developed velocity models to convert seismic reflections versus two-way travel time (TWTT) to reflections versus depth. In addition, the velocity models themselves provide insights into the structure of the Midcontinent Rift by recognizing common velocity ranges for certain rock types (Grauch, 2023).

eastern Lake Superior↗
USGS2026

Beyond technical expertise: The role of mindset, interpersonal, and intrapersonal skills in the development of fisheries professionals

Objective Recognized as essential components for success, mindset and inter- and intrapersonal skills (often referred to as soft skills) play a crucial role in the growth and effectiveness of individuals throughout their careers. Individuals with strong inter- and intrapersonal skills and a mindset open to growth can efficiently navigate complex challenges that may involve working with diverse stakeholder groups, managing interdisciplinary teams, or resolving conflicts in ways that allow them to excel beyond their technical skill sets. Although formal education of natural resources professionals (and many other professions) generally prioritizes technical skills, cultivating inter- and intrapersonal skills and a growth mindset is critical to success. Methods Drawing on presentations and discussion from an early-career symposium at the 2023 American Fisheries Society Conference, we summarize skill sets valuable for success in fisheries and natural resources. Results We provide an overview of the roles mindset and inter- and intrapersonal skills have in developing a career, how to use these competencies to navigate natural resources professions, and actions for enhancing personal skills. This paper aims to provide a compendium of information and lessons learned from natural resources professionals with diverse experiences and to emphasize familiar concepts to help formalize their discussion in the fisheries profession. Conclusion Fisheries and other natural resource fields have become increasingly interdisciplinary, necessitating a broad suite of skills to effectively communicate across disciplines, convey multiple data types, and make decisions to address complex problems. Inter- and intrapersonal skill sets are foundational to successfully navigating the fisheries profession. Moreover, personal skills transcend our profession into our everyday lives, thus strengthening personal skills is a worthy endeavor.

Fisheries↗
USGS2026

A novel method for quantifying streambed penetrability to inform benthic habitat assessment

Objective Penetrability of streambed sediments is important for the ecological functioning of many benthic organisms, yet there is ambiguity in terminology associated with this concept and there is no standardized method of penetrability measurement available to scientists and resource managers. The goal of our study was to better define the terms of compaction and penetrability as they relate to streambed substrate and to advance the measurement techniques for assessing penetrability of bed sediments in gravel-bed streams. Methods We tested the performance of a modified penetrometer method in 12 different substrate configurations in the laboratory and used the data to determine the relationship between penetration depth and substrate characteristics. We then simulated additional sampling effort and used bootstrapping methods to provide guidance on the number of samples required to achieve consistent results. Finally, we tested the device in a field setting to validate our laboratory and simulation results. Results Depth of penetration was negatively related to increasing substrate particle diameter and number of particle size-classes in both laboratory and field tests. Mean depth of penetration and CV stabilized after five samples, but variation remained high in scenarios containing large-grained particles. Conclusions Our results show that the device has application in gravel-bed streams but may require high amounts of sampling effort to capture variation in streams dominated by large substrate. We discuss the uses and limitations of this method for estimating substrate penetrability and provide guidance on interpretation of the estimates that it produces.

Transaction of the American Fisheries Society↗
USGS2026

Beyond barriers: Fish assemblage recovery following dam removal on the Cuyahoga River, a Lake Erie tributary

Dam removals are increasing globally, yet ecological outcomes vary widely because biological recovery depends on post-removal connectivity and access to source populations. We evaluated how multiple dam removals and remaining fragmentation influenced fish assemblage recovery in the Cuyahoga River (OH, United States), a historically polluted Great Lakes tributary now undergoing extensive remediation and restoration. Using fish assemblage data collected from 1984 to 2024 across reaches downstream, within, and upstream of the Gorge Plant Dam (GPD), an 18-m barrier slated for removal, we quantified spatial and temporal change with ordination, trajectory, and distance-based redundancy analyses. Downstream assemblages showed a clear shift through time and gained 15 newly detected taxa after the 2020 Brecksville Dam removal increased longitudinal connectivity to Lake Erie by 39 river kilometers, more than doubling free-flowing habitat below GPD. In contrast, assemblages upstream of GPD exhibited limited change and patterns consistent with redistribution of resident species rather than colonization-driven turnover. Across the full time series, site position relative to GPD and the rate of dam removal were the strongest predictors of assemblage variation, with habitat gradients (e.g. depth, velocity, turbidity, and canopy cover) further differentiating reaches. Together, these results show that connectivity and barrier position shape assemblage recovery following dam removal. Most newly detected taxa downstream were native, though three were nonnative, indicating trade-offs between recolonization and nonnative spread.

Ohio↗
USGS2026

Patterns of recent brook trout invasion in bull trout streams in relation to habitat, source connectivity, biotic resistance, and disturbance

Knowledge of which habitats are at risk of invasion by nonnative species is essential to conservation, but a changing climate often complicates assessments of where future invasions may occur. Nonnative brook trout Salvelinus fontinalis threaten cold-adapted native salmonids throughout western North America, and the extent of future invasions in coldwater streams is recognized as an area of uncertainty with important consequences. We addressed this uncertainty using spatial-stream-network (SSN) modeling to develop a species distribution model (SDM) for brook trout in Idaho, creating high-resolution prediction maps of suitable (i.e., invadable) habitat under baseline (1990–2015) and future (2080s) climate scenarios, and querying predictions within natal bull trout S. confluentus habitat patches (stream–subwatershed scale) for each scenario. Results indicated that brook trout will experience a net loss of suitable habitat in Idaho, but a large increase of suitable habitat in cold streams. The total proportion of bull trout habitat invadable by brook trout increased from 0.33 during the baseline scenario to 0.44 during the future scenario—a result of upstream expansions of brook trout habitat that were partially offset by contractions in bull trout habitat. Changes in the proportion of invadable habitat varied widely among bull trout patches. Between scenarios, the largest increases in suitable habitat occurred in small, low-gradient, unconfined streams with mean August water temperatures of 7–9 °C during the baseline period. A relatively small proportion of patches contained the majority of invadable habitat in both scenarios, particularly patches in “U-shaped” glacial valleys. A changing climate will broadly increase the threat that brook trout pose to bull trout, but the degree of change experienced by individual populations will vary with local context. The high-resolution prediction maps created by our SSN model will help conservation planners identify and prioritize control efforts on the small proportion of brook trout populations that most threaten bull trout.

Idaho↗
USGS2026

Assessment of undiscovered conventional oil and gas resources in the Berkine, Illizi, Hamra, Murzuq, and Erdis Kufra Basins of northern Africa, 2026

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 419 million barrels of oil and 5.5 trillion cubic feet of gas in the Berkine, Illizi, Hamra, Murzuq, and Erdis Kufra Basins of northern Africa.

Berkine, Illizi, Hamra, Murzuq, and Erdis Kufra Ba↗
USGS2026

The Great Lakes Geologic Mapping Coalition—Working collaboratively to understand the geology of the Great Lakes Region

Introduction The Great Lakes Geologic Mapping Coalition (GLGMC), commonly referred to as the “Coalition,” is a partnership between the U.S. Geological Survey (USGS), the U.S. States of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin and the Canadian province of Ontario. The member States receive funding for geologic mapping work from the USGS National Cooperative Geologic Mapping Program (NCGMP), whereas Ontario participates as a nonfunded partner. The mission of the GLGMC is to produce three-dimensional (3D) geologic maps that depict unconsolidated sediments and near-surface bedrock in the Great Lakes region of North America. Geologic maps are the basis of most earth science investigations and help support resource exploration (energy, minerals, groundwater), natural hazard mitigation, infrastructure development, and land-use planning, all of which can be used to advance economic development and strengthen national security in the Great Lakes region. During the last few million years, the Great Lakes region has experienced repeated glacial advances and retreats, leaving behind extensive sediments, abundant natural resources, and widespread effects on the underlying bedrock geology (Swezey and others, 2022). Linked by shared histories of past glaciations, industrial agriculture, and legacy automotive, coal, steel, and manufacturing industries, the GLGMC member States collaborate to improve the understanding of the 3D distribution of the sediments overlying the region’s bedrock (fig. 1). Developing a comprehensive subsurface 3D framework of this glaciated terrain can provide earth science data to policymakers at all levels. These insights facilitate informed decisions on the exploration, use, and protection of vital resources, such as critical minerals, industrial materials, and aquifers, thereby supporting economic prosperity and the well-being of the citizens of this region. Since its inception in 1998, the Coalition has completed more than 100 geologic mapping projects across the Great Lakes region. Each project aims to deliver geologic maps, 3D datasets, and other information that improves understanding of the geology of the Great Lakes region, with an emphasis on economic and water resources. Key deliverables include 3D geologic maps and models typically portraying sediment thickness, often derived from top-of-bedrock and borehole data. These products are developed through a combination of fieldwork, subsurface modeling, and the collection and analysis of rock and sediment cores. To support Coalition goals, member States collaborate with scientists working on related STATEMAP, EDMAP, and FEDMAP projects. Coalition scientists also engage with Tribal Nations in the Great Lakes region to ensure that Tribal interests pertaining to Coalition work are addressed. Through this collaboration, the Coalition unites the efforts of State, Federal, and Tribal Nation stakeholders to advance geologic data production and enhance understanding of the geologic resources of the Great Lakes region.

Illinois, Indiana, Michigan, Minnesota, New York, ↗