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USGS2024

Formation of vertical columnar seismic structures and seafloor depressions by groundwater discharge in the drowned Miami Terrace platform and overlying deep-water carbonates, southeastern Florida

The presence of vertical cross-formational fluid migration passageways within sedimentary basins can profoundly impact aquifer and reservoir fluid-flow and their identification is fundamental to informing management of subsurface fluid resources (groundwater, oil, gas). In an onshore and offshore southeastern part of Florida, 2D/3D seismic-reflection and bathymetry data document ∼153 vertical columnar structures composed of reflection disruptions up to 790 m in the height and averaging 360 m in diameter, and ∼219 subcircular to circular seafloor depressions up to 1334 m wide. Our study focuses on these features found within the offshore shallow-marine carbonate Miami Terrace platform, which drowned approximately at the end of the middle Miocene, and within overlying Plio-Quaternary deep-water carbonate slope and drift deposits. Most columnar structures are rooted in stratiform aquifers of the Miami Terrace platform and associated with faults or fault intersections produced by Eocene and circa late Miocene tectonics. The columns commonly terminate within the platform or as subcircular depressions along an amalgamated karstic and drowning unconformity at the platform top. The columns typically stretch upwards from a zone of deep karst cavity collapse through the Miami Terrace platform with upward decreasing sag on internal reflections. Following drowning and Plio-Quaternary partial burial of the Miami Terrace platform by deep-water deposits, the subcircular depressions and faults along the platform top were points of origin for a second phase of column growth upward into the deep-water deposits. The continuation of deep platform cavity collapse and column evolution produced pockmarks along paleo-seafloors within the deep-water deposits and at the present-day sea floor. The Plio-Quaternary pockmarks formed at water depths too deep to suggest an origin related to meteoric karst above or near sea level, but rather their formation is suggested to be related to cyclic sea level falls that drove increased groundwater head and density gradients, and seafloor discharge of offshore freshened groundwater sourced from the underlying platform. Plausibly, mixing of freshened groundwater and seawater at the seafloor discharge sites drove dissolution of the host deep-water deposits, which together with erosion by groundwater venting and current scouring formed the pockmarks. Seaward of the Plio-Quaternary seafloor pockmarks, at the late-middle Miocene upper slope of the Miami Terrace platform and along the regional karst/drowning unconformity is a slope-parallel band of ∼189 densely distributed subcircular seafloor depressions with diameters up to 1334 m at water depths up to ∼660 m. It is plausible that along the upper slope, faults and fractures produced by gravity-driven slope instability and possibly tectonics formed a dense network of fluid passageways that promoted upward artesian freshened groundwater flow to sites of discharge where mixing with seawater generated limestone dissolution and the depressions. But tectonic uplift may have forced emersion and initial meteoric sinkhole formation circa late Miocene with later enhancement by freshened groundwater discharge and bottom current erosion.

Florida↗
USGS2024

Hyperspectral (VNIR-SWIR) analysis of roll front uranium host rocks and industrial minerals from Karnes and Live Oak Counties, Texas Coastal Plain

VNIR-SWIR (400–2500 nm) reflectance measurements were made on the surfaces of various cores, cuttings and sample splits of sedimentary rocks from the Tertiary Jackson Group, and Catahoula, Oakville and Goliad Formations. These rocks vary in composition and texture from mudstone and claystone to sandstone and are known host rocks for roll front uranium occurrences in Karnes and Live Oak Counties, Texas. Spectral reflectance profiles, 569 in total, were reduced to 125 representative spectral signatures, which were analyzed using the U.S. Geological Survey's (USGS) Material Identification and Characterization Algorithm (MICA). MICA uses an automated continuum-removal procedure together with a least-squares linear regression to determine the fit of observed sample spectral absorption features to those of reference mineral standards in a spectral library. The reference minerals include various clay, mica, carbonate, ferric and ferrous iron minerals and their mixtures. In addition, absorption feature band-depth analysis was done to identify rock surfaces exhibiting absorption features related to uranium and zeolite minerals, which were not included in the command files used to execute MICA. Rocks from each of the four geologic units produced broadly similar spectral signatures as a result of comparable mineral compositions, but there were some notable differences. For example, Ca- and Na-montmorillonite was matched most frequently to the spectral absorption features in 2-μm (∼2000–2500 nm) wavelengths, while goethite occurred often at 1-μm (∼400–1000 nm) wavelengths. The latter is related to limonitic iron-staining in and around oxidized zones of the uranium roll front as described in previous papers. Rocks of the Jackson Group differed from those of the Catahoula, Oakville and Goliad units in that the former exhibited spectral features we interpret as being due to the presence of lignite-bearing mudstone layers. Goliad rocks exhibit spectral features related to dolomite, gypsum, anhydrite, and an unidentified green clay mineral that is possibly glauconite . Jackson Group rocks also exhibit weak but well-resolved absorption features at 964 and 1157 nm related to either or both zeolite minerals clinoptilolite and heulandite. These zeolite minerals and a few spectra exhibiting hydrous silica absorption features are indicative of alteration of volcanic glass in tuffaceous mudstone and claystone layers. A few sample spectra exhibited strong absorption features at around 1135 nm related to the uranium mineral coffinite. Both the 1135 nm coffinite and 1157 nm zeolite absorption features overlap somewhat, potentially making them difficult to distinguish without additional hyperspectral field, laboratory or remote sensing data. The results of this study were compared to mixtures of minerals described for ore, gangue and alteration minerals in deposit models for sandstone-hosted uranium, sedimentary bentonite and sedimentary zeolite. Use of these spectra can help facilitate mapping of both waste materials from the legacy mining of the above commodities, as well as future exploration and resource assessment activities.

Texas↗
USGS2025

Summary of results from monitoring the Geysers with continuous passive seismic and repeat magnetotelluric measurements (2021-2023)

Understanding temporal variations in a geothermal field can support operators in decision making that pertains to optimizing production and mitigating hazards. Between 2021 and 2023, The Geysers geothermal field in northern California was monitored with an array of continuous passive seismic sensors and annual repeat magnetotelluric (MT) measurements. Each of these data sets were analyzed and modelled separately to understand the data, sensitivity, and any observable changes. Then, the data were inverted jointly using a crossgradient method to further constrain temporal changes in geophysical properties within the geothermal field. Multiple permutations of annual datasets were used as inputs to the joint inversion. Results demonstrate seismic data constrain smooth inversion of the MT data, and the MT data provide supplementary information about the location of temporal fluid changes. Estimating relative changes in steam saturation for various time intervals of the joint models shows compartmentalized changes in the field, and good spatial correlation with the location of injection wells. These results demonstrate that collecting both passive seismic and MT measurements then modeling them jointly provide complementary information and a relatively inexpensive method for monitoring temporal changes in an active geothermal field that provides results to support operators.

California↗
USGS1976

Availability of ground water in the area surrounding the Trident submarine construction facility, Kitsap County, Washington

This report provides general information on the water resources--with emphasis on ground-water occurrence and availability--in that part of Kitsap County (referred to as Trident Impact Area) that would be most affected by the development of the Trident submarine-construction facility at Bangor. Ground water occurs principally in a lower, confined aquifer near and below sea level and an upper, unconfined aquifer above sea level; both aquifers are extensive beneath the study area and are composed of sand and gravel layers separated by poorly permeable silt, clay, and till layers. Locally throughout the area efficiently constructed wells tapping each of the two aquifers are capable of yielding 100 to 1,300 or more gallons per minute. The estimated 1970 water use in the study area averaged about 13 million gal/day (gallons per day); of this amount about 9 million gal/day came from surface-water sources--from a large reservoir outside the study area--and about 4 million gal/day came from ground water pumped from the two aquifers. Anticipated water use soon will be about 18 to 21 million gal/day; virtually all the additional quantity required (about 5 to 8 million gal/day) above present use must come from ground-water sources. Preliminary evaluation of the aquifers suggests that an additional 1.5 million gal/day can be developed from the upper aquifer and 7 million gal/day from the lower aquifer. Existing wells tapping the lower aquifer might yield additional water and increase the total yield in the area by 3.5 million gal/day, and new wells drilled in selected areas could produce an additional 3.5 million gal/day from this aquifer. However, additional, large-scale ground-water withdrawal from the lower aquifer could induce saltwater intrusion into wells situated in coastal areas. Recommended future studies include additional data collection, monitoring of chloride concentrations in water from large-yield coastal wells, confirmation of well yields and capacities, and test-well drilling and analysis.

Washington↗
USGS2025

Case study of deep learning image segmentation for the purposes of rapid 2D petrographic analysis in volcanic rocks

Automation using deep learning methods is a useful alternative to manual methods of petrographic segmentation, but often requires user familiarity with coding and/or algorithms. We examine the Dragonfly TM program's deep learning tools for application by users with a variety of skill levels as a method for petrographic image segmentation. An image processing methodology, bimodal image stacking, was created for low-input-data, high-efficacy training of models which can then be applied to varied samples. Using backscatter electron images we show that the resulting model segmentations agree with manual segmentation total and modal crystallinity values within 5%, and calculated plagioclase crystal size distribution (CSD) values within 2σ, despite limitations in discriminating mafic phases. Model creation and training takes <24 hours, 1–3 hours of which are supervised, and the resultant model can then be applied to new uncharacterized samples in <15 minutes per image. This allows for non-experts to create and utilize deep learning models to segment images of variable brightness and texture, at low user-time cost and resulting in size and shape data which are within uncertainty of manual segmentation. While some limitations are noted (for example, sieve-textured phases may need manual correction, and different minerals with similar BSE intensity may not be resolved as separate phases), this methodology can be utilized for general application of models to wide ranges of volcanic crystalline and bubble textures, and to create a library of models for rapid petrological analysis during volcanic eruptions.

Alaska↗
USGS2026

Groundwater-level elevations in the bedrock aquifers of the Denver Basin aquifer system, Elbert County, Colorado, 2015–23

Water users in Elbert County, Colorado, rely on groundwater from bedrock aquifers in the Denver Basin aquifer system (upper Dawson, lower Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers) for approximately half of their water uses. Withdrawals from the bedrocks aquifers have increased to meet the water use needs of expanding regional population growth and development. The U.S. Geological Survey, in cooperation with the Elbert County Board of County Commissioners, began a study in 2015 to monitor groundwater levels within Elbert County. The primary purpose of this report is to present a summary of groundwater levels measured during the study period (2015–23) and present results from statistical analyses of changes in groundwater-level elevations through time. Discrete groundwater levels were measured at 36 wells within Elbert County. Seven of those wells contained equipment to make and record continuous groundwater-level measurements at hourly intervals. All aquifers, except the lower Dawson aquifer, had only declining groundwater-level elevations in discrete measurements for wells with statistically significant trends. Of the eight statistically significant trends in the lower Dawson aquifer, two wells indicated increasing groundwater-level elevation from discrete measurements. The groundwater-level elevation trend medians in the upper Dawson, lower Dawson, Denver, Arapahoe, and Laramie-Fox Hills aquifers were −0.23, −0.66, −0.64, −0.39, and −0.63 feet per year, respectively, for discrete groundwater-level elevation measurements. Trends in continuous groundwater-level elevations were in agreement with statistically significant trends in discrete groundwater-level elevations for all wells. The groundwater-level elevation trend medians in this study, compared to the overall trends in a 2015−2018 study, both indicated declining groundwater-level elevations except in the upper Dawson aquifer, where the trend direction was opposite, a positive trend from 2015 to 2018 and a negative trend (declining groundwater elevations) from 2015 to 2023. The change in trends within the upper Dawson aquifer may be affected by differences in the study period and the trend analysis applied. Trends during the 2015–23 study period were compared to departures from the median 2015 groundwater-level elevation for each site in each aquifer. In general, the departures from the 2015 median supported trends observed at each site and correlated spatially with greater departures near the western border of Elbert County. Additionally, 30-year precipitation data showing wet and dry periods were overlaid with the departure from the 2015 median to assess groundwater-level patterns in wells in the five aquifers. Departures from the 2015 median groundwater-level elevations appeared greatest during the dry period between 2020 and 2023. Potentiometric-surface maps of the upper and lower Dawson aquifers created from static April 2023 groundwater elevations indicated groundwater-flow direction is generally from the south to the north. Results of this study could be used to guide additional groundwater monitoring in Elbert County and could aid in long-term planning of water resources.

Colorado↗
USGS2025

Earthquake magnitude and source parameter estimation with a distributed acoustic sensing dataset in the Gorda subduction zone

Distributed acoustic sensing (DAS) systems offer a cost‐effective way to create large‐scale strainmeter arrays for seismological applications using fiber‐optic cables. DAS‐based strain measurements are known to be influenced by various factors, bringing into question their general reliability for accurate earthquake characterization. A 15‐km‐long DAS deployment in northern California was operational within 3 days of the 2022 M w 6.4 Ferndale earthquake and ran continuously throughout the aftershock sequence. We utilize these aftershock data to validate DAS‐based strain measurements in two ways. We first test the accuracy of DAS‐based magnitude estimates from peak dynamic strains by comparing them with magnitude and attenuation scaling relations derived independently from traditional borehole strainmeter (BSM) data. We demonstrate that DAS‐based magnitudes are comparable to BSM‐based magnitudes when corrections for variations in site response along the fiber‐optic cable are properly made. Magnitude errors are spatially correlated, potentially because of factors such as finite‐fault effects (e.g., stress drop) or more complex, unmodeled path attenuation or because of wave propagation effects in heterogeneous media. We then apply more advanced source characterization methodology to the DAS data using a time‐domain empirical Green’s function (EGF) deconvolution approach to measure details of the moment rate history. The EGF approach using DAS data depends on careful treatment of distorting factors such as anthropogenic sources of noise and optical phase wrapping but successfully isolates source spectra for moderate‐magnitude earthquakes: source spectral ratios obtained from DAS data, broadband seismometer data, and BSM data in the same region show consistent results, revealing differences in directivity and spectral shape among earthquakes. Although further research is needed to refine source‐time‐function estimation techniques for DAS data, particularly for larger magnitude events, these case studies demonstrate the clear potential of DAS for earthquake source characterization.

California↗
USGS2025

Metal fingerprints of Eocene rhyolite magmas coincident with Carlin-type gold deposition in Nevada USA

Eocene magmatic systems contemporaneous with world-class Carlin-type Au deposits in Nevada (USA) have been proposed by some researchers as a key ingredient for Au mineralization, though evidence conclusively demonstrating their genetic relationship remains tenuous. This study provides the first direct evidence of the pre-eruptive metal budget of volatile- and metal-charged silicic magmas coincident in time (~41 to 34 Ma) and space (within 5 km) with Carlin-type Au deposits. We characterize the pre-eruptive metal fingerprints of these diverse magmatic systems to assess their potential as sources of metals for Carlin-type Au mineralization. Metal abundances from quartz-hosted melt inclusions (Au, Te, Ag, Sb, Tl, Mo, W, Sn, As, Pb, Co, Cu, Ni, and Zn) characterized in situ by SHRIMP-RG and LA-ICP-MS represent our best (and only) estimates for the pre-eruptive metal budget in these systems. Median metal concentrations are generally within one order of magnitude of average upper crust and average continental rhyolite values. But there are two notable exceptions, with median Au contents extending >1 order of magnitude higher than average upper crust and median Cu contents ranging >1 order of magnitude lower than upper crust. Despite this, melts contain lower Au/Cu (<0.1), Au/Ag (<5), and Au/Tl (<0.3) than most ore-grade Carlin-type rock samples and quartz-hosted fluid inclusions, regardless of their age and timing relative to nearby Carlin-type Au mineralization. The metal fingerprints of these magmatic systems, de-fined both by traditional and multivariate compositional data analysis techniques, are distinct from one another. Yet none are particularly specialized, e.g., high Au/Cu, in terms of being ideal ingredients as postulated by magmatic models for Carlin-type Au mineralization. Magmatic Au contents do not appear to be correlated with rhyolite “flavors” in the way that Cu, Sn, and Nb contents are. Fluid/melt partitioning modeling and magma volume estimates support the idea that a diverse array of non-specialized silicic magmas could feasibly contribute some or potentially all of the Au, Ag, and Cu in Carlin-type systems. The compositional diversity among contemporaneous magmatic systems could possibly contribute to some of the diversity observed across Carlin-type Au districts in Nevada.

Nevada↗
USGS2024

Long-term communication of aftershock forecasts: The Canterbury earthquake sequence in New Zealand

On 14 February 2016, a magnitude (M)5.7 earthquake struck in Christchurch New Zealand (Aotearoa in the Maori language). The shaking caused damage to historic facades, power outages, cliff collapses, rock falls, and liquefaction but no reported injuries or fatalities. This Valentine’s Day earthquake was an aftershock in the Canterbury earthquake sequence (CES), which began on 4 September 2010 with the M7.1 Darfield Earthquake and included the destructive and fatal M6.2 Christchurch aftershock on 22 February 2011. This study, eight months after the Valentine’s Day earthquake and six years after the initiation of the CES, is the first to explore long-term aftershock forecast information and communication needs. The exploratory study also aimed to gather feedback on aftershock scenarios, an alternative form for communicating the forecast. The qualitative study involved workshops with emergency managers, public health officials, and members of the public in Christchurch. Key findings for long-term communication throughout an earthquake sequence include: 1. divergent earthquake experiences affect aftershock communication response and information needs; 2. understanding aftershock sequence behavior is foundational to sense-making when large aftershocks occur; 3. strategic earthquake sequence updates from the trusted science agency and local agencies could serve as important reminders for earthquake preparedness; 4. communication of aftershock forecast uncertainty could aid with both the credibility of the information and living with uncertainty, and 5. inclusion of impact information and preparedness advice into aftershock forecast scenarios could provide links to actionable information. The paper derives implications for research and practice of long-term communications during an aftershock sequence.

Christchurch↗
USGS2024

Influence of inherited structure on flexural extension in foreland basin systems: Evidence from the northern Arkoma basin and southern Ozark dome, USA

Extensional faults are key components of foreland basin systems. They form within the upper crust in response to flexure of the lithosphere and accommodate subsidence within the foredeep and forebulge depozones. Such faults are excellent proxies for orogenic system evolution and control the distribution of natural resources and hazards. However, the spatiotemporal evolution of flexural extension has not been documented previously at a regional scale, thereby limiting our understanding of underlying geodynamic controls. Here, we resolve late Paleozoic flexural extension in the northern Arkoma basin and southern Ozark dome, USA. We synthesize a large database of previous mapping, existing research, subsurface data, and geophysical data into 3D geologic and 2D kinematic models. Mesh surfaces representing several key horizons from the Carboniferous Period (ca. 335-306 Ma) were constructed. These surfaces were built from oil and gas well tops (n = ∼10,000) and surface geologic map contacts using an advanced kriging method. The mesh surfaces are offset by a complex 3D fault network, allowing detailed analysis of along-strike and down-dip variations in fault displacement. Analysis of the 3D model reveals a regular and repeated fault segmentation pattern wherein E -W striking, left- and foreland-stepping en échelon normal faults are segmented by inherited NE striking basement faults. Maximum vertical separation along the E -W normal faults is generally focused between the inherited NE-trending faults. This suggests that the inherited basement faults delocalized extensional strain during late Paleozoic normal faulting. Maximum vertical separation and fault localization may correlate to areas with high-amplitude positive magnetic anomalies interpreted as Mesoproterozoic granitic rocks. Speculative covariance of magnetic anomalies and fault displacements implies that the relatively strong basement granite concentrated stress, leading to localized faulting within the relatively thin sedimentary cover. Lastly, we show that flexural extension migrated southeast to northwest from the Chesterian-Morrowan (ca. 335-319 Ma) to the Desmoinesian (ca. 306 Ma). The migratory flexural extension may be explained by diachronous loading during Pangean assembly, or by synchronous loading but variable load compensation due to inherent factors.

Arkansas, Oklahoma↗
USGS2025

A probabilistic assessment methodology for the evaluation of geologic energy storage capacity—Natural gas storage in depleted hydrocarbon reservoirs

The need for energy storage, particularly underground, where capacity and duration may far exceed battery storage technologies, is especially relevant given the increasing demands for reliable power alongside the development of intermittent renewable electricity sources. Geologic energy storage facilities already exist, and expanded use would enable storing gases such as methane and hydrogen. In 2018, a National Academies of Sciences, Engineering, and Medicine report, “Future Directions for the U.S. Geological Survey's Energy Resources Program,” recommended that the U.S. Geological Survey (USGS) prioritize assessing underground energy storage in geologic formations in the United States. The U.S. Geological Survey has since developed a methodology for assessing natural gas storage capacities in depleted hydrocarbon reservoirs on a national scale. The methodology introduced in this report prescribes three approaches for calculating gas storage capacity. This methodology relies on the availability of input data, including cumulative hydrocarbon production records, reservoir petrophysical properties, and reservoir pressure data. Assessment inputs can be obtained from public, State-level databases and propriety national-scale databases, although the use of analogs could be warranted for estimating input parameters. Probabilistic assessment results are aggregated to play, petroleum province, regional, and national scales. The steps defined in this report are demonstrated on the Michigan Basin Province, which includes the Mississippian Sandstone Gas Play and the Clinton Structural Play. This methodology could be used to systematically and consistently assess hydrocarbon plays and provinces for natural gas storage capacity across the United States.

Michigan↗
USGS2026

Critical minerals in zinc ore—An update on Earth Mapping Resources Initiative Research in the Boulder Batholith region, Montana

Plain Language Summary U.S. Geological Survey research, in collaboration with Montana Technical University and Montana Bureau of Geology and Mines, is providing key critical mineral information that may have potential for critical mineral production of several mining districts in the Boulder Batholith region, to better understand the abundance and distribution of natural resources within this region. Continued research can be used to show the potential for previously undiscovered critical mineral resources in southwestern Montana and in other parts of the United States.

Montana↗
USGS2026

Wind River subbasin restoration: Annual report of U.S. Geological Survey activities January 2024 through December 2024

We sampled juvenile wild Oncorhynchus mykiss (Steelhead Trout) in headwater streams of the Wind River, Washington, to characterize population attributes and investigate life-history metrics, particularly migratory patterns, and early life-stage survival. Additionally, this sampling provides an index of abundance of non-native Brook Trout Salvelinus confluentus . We used passive integrated transponder (PIT) tagging and a series of instream PIT-tag interrogation systems (PTISs) to track juveniles and adults. The Wind River subbasin is considered a wild Steelhead refuge by Washington Department of Fish and Wildlife (WDFW). No hatchery Steelhead Trout have been released in the Wind River subbasin since 1997, and hatchery adults are estimated at less than one percent of spawners in most years. Over 25 years of Steelhead Trout status and trend monitoring and research in the subbasin is contributing to understanding of population response to numerous restoration actions in the subbasin, including removal of Hemlock Dam from Trout Creek in 2009, which had an inadequate adult ladder and contributed to increased water temperatures, to near lethal levels for salmonids. Data from our study, and companion work by WDFW, are contributing to the Columbia Basin Fish and Wildlife Program (2009) Research, Monitoring, and Evaluation (RM&E) Strategy of Fish Population Status Monitoring. Specifically, this work addresses the sub-strategies of 1) Assessing the Status and Trends of Diversity of Natural Origin Fish Populations and Uncertainties Research regarding differing life histories of a wild Steelhead Trout population, 2) Assessing the Status and Trend of Adult Natural Origin Fish Populations, and 3) Monitoring and Evaluating the Effectiveness of Tributary Habitat Actions Relative to Environmental, Physical, or Biological Performance Objectives. During summer and fall 2024, we PIT-tagged 2,075 Steelhead Trout parr (age-0 and age-1), in the Trout Creek and upper Wind River watersheds. Age-0 and age-1 parr were at high abundance due to strong spawner numbers in 2023 and 2024 (Estimate of 932 in 2023; and a moderate number of spawners in 2024 though an estimate is not available at this time; 24-year median = 619; Charlie Cochran, WDFW Fish Biologist, personal commun., 2025). An additional 100 parr (age-0 and age-2 or older) were tagged to provide fish for estimating detection efficiencies at PTISs. Steelhead Trout parr were recaptured and detected through repeat headwater sampling, smolt trapping, instream PTISs and Columbia River mainstem PIT-tag detection. We maintained and upgraded six instream PTISs to detect PIT-tagged Steelhead Trout parr, smolts, and adults, providing data for population assessments, and life-cycle research. Detection data from PIT-tagged adult Steelhead Trout at our four primary PTISs allow assessment of adult escapement to tributary watersheds within the Wind River subbasin. Most adult Steelhead detected were tagged by WDFW at an adult trap in the lower Wind River and some as smolts at screw traps. Adult Steelhead Trout detection efficiency estimates at our primary PTIS in Trout Creek have been greater than 99 percent during eight of the past ten years and have exceeded 97% at our primary PTIS in the Wind River during nine of the past ten years. Adult escapement estimates to tributary watersheds are helping evaluate the efficacy of the 2009 removal of Hemlock Dam from rkm 2.0 of Trout Creek. Detections at the instream PTISs have shown trends of age-0 and age-1 Steelhead Trout parr emigration from natal areas during summer and fall, in addition to the expected movement of parr and smolts in spring. Our data suggest that most fish from a cohort that migrate downstream will do so at age-1 for additional rearing in the subbasin. We have estimated that from 15% to 56% of parr tagged as age-0 fish in headwater areas make downstream migrations at age-1 for additional rearing (median = 29%). We have estimated that from 1% to 27% of Steelhead Trout parr, tagged as age-1 fish, make downstream migrations during fall (median = 3.5%): this is especially pronounced in the upper Wind River portion of the watershed (median 10%). These findings raise questions about parr rearing habitat and whether migrations are density- or habitat-quality driven, and answers to such questions are long-term goals of this study as active and passive habitat restoration occurs. Repeat sampling at sites in the subbasin within and between years has enabled assessment of juvenile Steelhead Trout growth patterns. Growth rates (relative change in weight) of age-0 PIT-tagged parr during summer have been similar across the subbasin, though slightly lower in the Trout Creek watershed (Trout Creek sites, 0.57 - 1.25%/day, Wind River sites = 0.94 – 2.48%/day). Summer growth rates have been lower for age-1 parr in the Trout Creek watershed than the upper Wind River watershed (Trout Creek sites, = 0.03 - 0.14%/day, Wind River sites = 0.05 – 0.19%/day). Yearly relative growth was similar across the subbasin for both age-0 and age-1 tagged parr. During 2024 range of mean daily relative change in weight from the previous year for age-0 tagged fish was: Trout Creek sites = 0.96 – 1.41%/day, Wind River sites = 0.80 – 1.30 %/day; and for age1 tagged fish was: Trout Creek sites = 0.37 - 0.50 %/day, Wind River sites = no age-1 tagged recaptures. Non-native Brook Trout are present in the subbasin, chiefly the Trout Creek watershed. Mean percent-of-catch that is Brook Trout, at four sample sites in Trout Creek, has declined from the period 1998 – 2003 to the period 2011 – 2024 (range of decrease = 19 - 82%). Percent-of-catch (of 64 samples, 52 < 10%; 3 > 20%) and number of Brook Trout at the Trout Creek sites from 2011 through 2024, though variable, have generally declined. Habitat restoration evaluation efforts are critical to ensure efficient use of money and resources but require long-term monitoring of population metrics. Detailed viable salmonid population and life-history data, such as that provided by PIT-tagging and instream PTIS networks inform fisheries policy and management and enable assessment of long-term effects of habitat restoration actions such as the removal of Hemlock Dam on Trout Creek and proposed major instream habitat restoration in the upper Wind River.

Washington↗
USGS2026

Tringa flavipes (Lesser Yellowlegs) from separate breeding sites subdivides the Prairie Pothole Region in space and time during southbound migration

Some staging regions support multiple groups of the same migratory species, each of which may use the region differently. Characterizing the ways, in which separate groups use such regions can therefore help to identify vulnerabilities during this sensitive period of the annual cycle. The Prairie Pothole Region (PPR) is a massive wetland complex in the northern Great Plains of North America used by ∼11 million shorebirds during migration. The PPR has been heavily modified by agriculture and is experiencing varied effects of global climate change, threatening the health of the shorebirds that rely on it. Here, we used 6 seasons of southbound tracking data of Tringa flavipes (Lesser Yellowlegs)—a long-distance migratory shorebird species with an estimated population decline of 63% over the last 4 decades—from 9 sites across their breeding range to explore differences in migratory behavior within this important staging region. We found that 75% of tracked individuals used the region during southbound migration, and T. flavipes from different breeding sites detoured 110–875 km from their most direct migratory route to access the PPR. Individuals that arrived later stayed longer and made more stops within the region than those that arrived early. Individuals originating from different breeding sites also displayed spatial and temporal segregation within the region: T. flavipes from southwest and central Alaska relied heavily on the northwestern PPR, while those from Canada used the central and southeastern portions of the PPR. Finally, timing of use varied among groups, but the southeastern PPR became increasingly important over the course of the southbound migratory window, as other wetlands likely dried out. Our study highlights the portions of the PPR of critical importance to migrating T. flavipes and the diversity of ways, in which different groups from within the same species can use a single staging region.

Alaska, Manitoba, Northwest Territories, Ontario, ↗
USGS2025

From hydrated silica to quartz: Potential hydrothermal precipitates found in Jezero crater, Mars

On Earth, silica-rich phases from opal to quartz are important indicators and tracers of geological processes. Hydrated silica, such as opal, is a particularly good matrix for the preservation of molecular and macroscopic biosignatures. Cherts, a type of silica-dominated rocks, provide a unique archive of ancient terrestrial life while quartz is the emblematic mineral of the Earth's continental crust. On Mars, hydrated silica has been detected in several locations based on remote sensing and rover-based studies. In the present article we report on the detection of cobbles made of hydrated silica (opal or chalcedony), as well as well-crystallized quartz. These detections were made with the SuperCam instrument onboard Perseverance (Mars 2020 mission), using a combination of LIBS, infrared and Raman spectroscopy. Quartz-dominated stones are detected unambiguously for the first time on the Martian surface, and based on grain size and crystallinity are proposed to be of hydrothermal origin. Although these rocks were all found as float, we propose that these detections are part of a common hydrothermal system, and represent different depths / temperatures of precipitation. This attests that hydrothermal processes were active in and around Jezero crater, possibly triggered by the Jezero crater-forming impact. These silica-rich rocks, in particular opaline silica, are very promising targets for sampling and return to Earth given their high biosignature preservation potential.

Earth and Planetary Science Letters↗
USGS2026

Flood-inundation maps of the Blue River and major tributaries in and near Kansas City, Missouri, 2023–25

Digital flood-inundation maps for 35.5 miles of the Blue River, in and near Kansas City, Missouri, were created by the U.S. Geological Survey (USGS) in cooperation with the City of Kansas City. Maps were also developed for a combined 7.3 miles of Brush Creek (4.4 miles) and Indian Creek (2.9 miles), two primary tributaries to the Blue River in the study reach. The flood-inundation maps, available through the USGS Flood Inundation Mapping Program website at https://water.usgs.gov/osw/flood_inundation/ , depict estimates of the areal extent and depth of flooding, depth of water above first-floor elevations in selected buildings, water velocity, water-surface elevations, and time of travel corresponding to selected water levels or gage heights (hereafter referred to as “stages”) at nine reference USGS streamgages—five on the Blue River (USGS station numbers 06893590, 06893578, 06893500, 06893150, and 06893100), two on Brush Creek (USGS station numbers 06893562 and 06893557), one on Indian Creek (USGS station number 06893390), and one on the Missouri River (USGS station number 06893000). Near-real-time stages at these streamgages may be obtained from USGS Water Data for the Nation at https://doi.org/10.5066/F7P55KJN or the National Weather Service National Water Prediction Service at http://water.noaa.gov/ , which also forecasts flood hydrographs at seven of these sites (USGS station numbers 06893000, 06893590, 06893578, 06893500, 06893150, 06893557, and 06893390). Flood profiles were computed for eight map reaches by means of two-dimensional hydraulic models. The models were calibrated using the USGS-developed stage–streamflow relations at each reference streamgage. Two map reaches on the lower Blue River also include the effects of backwater from the Missouri River on flood inundation extent and hydraulic characteristics. The hydraulic models were used to compute water-surface profiles for flood stages at 1-foot intervals referenced to the streamgage datums. The profile stages ranged from the National Weather Service “Action Stage” or near bankfull to a stage exceeding the highest recorded water level at each streamgage. The simulated water-surface profiles were then combined with a digital elevation model (derived from light detection and ranging data having a nonvegetated vertical accuracy of a maximum 10-centimeter root-mean-square error) to delineate the area flooded at each water level and the associated hydraulic characteristics. The availability of these maps, along with information regarding current stage from the USGS streamgage and forecasted high-flow stages from the National Weather Service, will provide emergency management personnel, resource managers, and residents with information that could be critical for flood-response activities such as evacuations and road closures, as well as for postflood recovery efforts.

Kansas, Missouri↗
USGS1983

Base flow and ground water in upper Sweetwater Valley, Tennessee

The upper Sweetwater Valley area has a flow system with complex interaction between surface and ground water. A water budget study indicated that during dry years approximately three-fourths of the annual flow to Sweetwater Creek may be derived from ground-water sources. Hydrograph analysis showed seasonal variation of recharge to the ground-water flow system. Streamflow records were analyzed to estimate the frequency of low flow of Sweetwater Creek at river mile 16.7, and indicated the lowest average flow for 1 day in 20 years to be about 5.1 cubic feet per second. Two periods of base-flow measurements of Sweetwater Creek identified channel reaches with significant gains and losses of streamflow. Base flow measurements also showed interbasin transfer of water among sub-basins of the valley. Major flow surpluses were associated with areas in which the majority of flow originated at a spring. Topographically low areas adjacent to the main stem of Sweetwater Creek generally have surplus flow. Topographically higher areas generally have deficient surface outflow unless significant spring flow occurs in the basin. Ground-water recharge occurs by water draining into sinkholes, faults, and fractures. Ground-water flow is regionally diffused across formation strikes from the topographically low areas unless the water is exposed to highly permeable formations or impervious formations. Ground water infiltrates the highly permeable formations and flows along strike. Ground water encountering impervious formations may discharge at small springs at the contact, or may reroute along the contact if the upgradient rock is sufficiently permeable or has well developed secondary porosity. Groundwater discharges to streams at innumerable seeps and at a few large springs. Areas of ground-water flow up-gradient of large springs are hypothesized as likely areas of significant ground-water reservoirs.

Tennessee↗
USGS2025

The geology of Canadian potash: A critical mineral for feeding the world

Potash, potassium-bearing water-soluble salt, is the primary global economic source of potassium. Potash is recognized as a critical mineral in Canada as it is the largest source of potassium used in fertilizers. It is essential for global agricultural productivity and food security. Canada is the world’s largest potash exporter with vast deposits in the widely mined Prairie Evaporite of Saskatchewan, which formed in the epicontinental Elk Point Basin during the Middle Devonian. Potash is also found in the Windsor Group of Atlantic Canada where it formed in a series of tectonically active basins during the Mississippian that have undergone substantial post-depositional subsurface alteration and deformation. Potash deposits were mined in New Brunswick up until 2016. Both deposits are salt giants, recording times in the geologic record of extensive and long-lasting evaporite genesis under arid conditions in restricted seas. This paper reviews the geological and economic significance of Canadian potash, including (1) the genesis of each deposit, (2) diagenetic, erosional, and tectonic modification, and (3) exploration and mining in each basin. Underdeveloped regions, possible undiscovered resources, environmental considerations, and the importance of sustainable practices in light of climate change and socioeconomic risks are also addressed.

Facets↗