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

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At least 829 records · Page 46Linked to original sources
USGS1973

Two diamictons in a landslide scarp on Admiralty Island, Alaska, and the tectonic insignificance of an intervening peat bed

Two till-like diamictons, 700 feet above present sea level on Admiralty Island, Alaska, are separated by peat near the top of a landslide scarp. The lower diamicton is glaciomarine; the upper diamicton is probably a mudflow. The lower diamicton contains the foraminifer Elphidium clavatum Cushman, a species typical of fiords. Similar diamicton crops out along Gastineau Channel near Juneau, 15 miles eastward. Diamicton in both areas reflects deposition in glacier-free fiords during land depression and sea transgression. Consequently, till-like deposits less than 700 feet above sea level elsewhere in southeastern Alaska should be considered as possibly glaciomarine. Sliding occurred after late 1962, but before July 1964; the March 27, 1964, Alaska earthquake might have caused sliding of diamicton saturated by melting snow and spring rains. The peat in the landslide scarp has a published radiocarbon date of 3,400±250 years B.P. (W-1955). The peat was expected to be older, and to relate to Holocene tectonic movement of Admiralty Island. The unexpectedly young date led to additional field study that showed the material over the peat to be a probable mudflow derived from glaciomarine diamicton upvalley; the date has no tectonic significance.

Alaska↗
USGS1977

Rare earths, thorium, and other minor elements in sphene from some plutonic rocks in west-central Alaska

Sphene is an abundant accessory mineral in some abnormally radioactive plutonic rocks in west-central Alaska. Seven samples of sphene from four different areas in west-central Alaska contained from 20350 to 39180 parts per million total rare earths and 390 to 2000 ppm thorium. The lanthanide content in six of the seven sphenes is chiefly the light rare earths and is similar to that of crustal abundance; a seventh sphene from the Darby Mountains, however, contains above average amounts of the heavy rare earths. A comparison of the lanthanide distribution in sphene from several areas indicates that the structure of sphene will accommodate whatever lanthanides are available when the mineral crystallizes. The amount of thorium and rare earths in sphene is also affected by the presence of other accessory minerals. Sphene in rocks containing either allanite or zircon has a lower thorium content than in rocks that do not contain allanite or zircon. Sphene, because of its abundance, may contain the greater part of the rare earths and thorium in some of the plutonic rocks of west-central Alaska.

Alaska↗
USGS1999

Bar-tailed Godwits Limosa lapponica in Alaska: A population estimate from the staging grounds

Bar-tailed Godwits Limosa lapponica were surveyed on their staging grounds in Alaska during September 1995 and 1997. The single high count of 94,000 birds closely matched that of counts from New Zealand and south-eastern Australia, the known non-breeding area for most of the baueri subspecies. Numbers recorded on the southern Yukon-Kuskokwim River Delta and at Egegik Bay, a small estuary along the Alaska Peninsula, qualify both areas as Hemispheric Reserves under the Westem Hemisphere Shorebird Reserve Network, as sites within the East Asian-Australian Shorebird Reserve Network, and as Ramsar sites. The breeding origins, destinations, and taxonomic affinities of Bar-tailed Godwits staging on the coast of south-west Alaska need further assessment.

Alaska↗
USGS1982

Population and status of Emperor Geese along the north side of the Alaska Peninsula

We gathered information on the timing of spring and autumn migration of Emperor Geese Anser canagicus from Nelson Lagoon, the age ratios of geese during autumn migration, and the numbers of geese in estuaries along the north side of the Alaska Peninsula and Bristol Bay during spring and autumn migration. Birds staged in most of the lagoons and bays along the north side of the Alaska Peninsula, but Nelson Lagoon and Seal Islands Lagoon were the most heavily used. Geese concentrated in Nelson Lagoon for about six to eight weeks in both spring and autumn. We suspect that the population of Emperor Geese in Alaska may have declined by as much as 34% between the 1960's and 1981. Although the average number of young per successful breeding pair has remained high during this period, the overall proportion of young in the population has been extremely low, at least during the past five years. More studies are necessary to determine factors influencing the status of this species.

Alaska↗
USGS2005

Seabird, fish, marine mammal, and oceanography coordinated investigations (SMMOCI) in Sitka Sound, Alaska, July 2000

Surveys for seabirds and marine mammals were conducted in and near Sitka Sound, Alaska (Fig. 1) from the M/V Tiĝlax̂ during 12-16 July 2000 (Table 1, Fig. 1). The objective was to characterize the marine environment in the vicinity of St. Lazaria Island, one of ten seabird colonies monitored annually by the Alaska Maritime National Wildlife Refuge (See Dragoo et al. 2003). In addition to censusing seabirds and mammals encountered on line transects, local oceanography was characterized by measuring water temperature and salinity continuously at the sea surface, and by taking profiles of the water column on a series of CTD transects. The relative abundance of zooplankton and fish biomass was measured using a dual -frequency echosounder. Significant acoustic targets were sampled with a m id-water trawl net. Long-lines were se t twice to catch and characterize diets of large demersal fish species. Rosenthal et al. (1981 and 1982) studied the bottomfish component of the nearshore habitats in southeastern Alaska including the Sitka Sound area during the summers of 1980 and 1981, allowing comparisons of our findings to those from the earlier works. There are no previous surveys for seabirds or marine mammals in this area with which we can compare our surveys.

Alaska↗
USGS2003

A genetic study to aid in restoration of murres, guillemots and murrelets to the Gulf of Alaska

Genetic data are needed to aid in restoring several species of seabirds to the Gulf of Alaska. We analyzed sequence variation in mitochondrial DNA, microsatellite DNA and nuclear introns in samples of commom murres ( Uria aalge ), pigeon guillemots ( Cepphus columba ) and marbled murrelets ( Brachyramphus marmoratus ) from throughout the North Pacific. Data were analyzed using traditional approaches, nested clade analyses and assignment tests. No cryptic species were found, and there was no strong evidence for inbreeding, low genetic variation, or souce or sink regions in any them. Pacific common murres constitute a single genetic management unit (MU), but hybridization occurs between common and thick-billed murres ( U. lomvia ). In contrast, gene flow in pigeon guillemots is very restricted and population genetic structure is very strong; guillemots from the spill area are part of a MU that extends from the Alaska Peninsula to somewhere between Prince William Sound and Vancouver Island. Marbled murrelets in the spill area are part of a MU that extends from the Alaska Peninsula to at least British Columbia; tree- and ground-nesting murrelets are not genetically differentiated. Little if any hybridization occurs between marbled and Kittlitz's murrelets.

Alaska↗
USGS2020

Petrophysical and geomechanical properties of gas hydrate-bearing sediments recovered from Alaska North Slope 2018 Hydrate-01 Stratigraphic Test Well

Knowledge of petrophysical and geomechanical properties of gas hydrate-bearing sediments are essential for predicting reservoir responses to gas production. The same information is also needed for the designing of production well completions such as specifications for artificial lift, test site water storage capacity, and mesh size for the sand control systems. In December 2018, the Stratigraphic Test Well Hydrate-01 was drilled in the western part of the Prudhoe Bay Unit on the Alaska North Slope as part of the technical planning effort for a future long-term production test being planned and led by a collaborative team from the U.S. Department of Energy - National Energy Technology Laboratory (DOE-NETL), U.S. Geological Survey (USGS), and Japan’s Research and Development Consortium for Pore Filling Hydrate in Sand (MH21-S) (Boswell et al., 2020, Collett et al., 2020, Okinaka et al., 2020). Logging-while-drilling (LWD) data were acquired (Haines et al., 2020, Suzuki et al., 2019) and sidewall core sampling depths were selected from the LWD logs. Sidewall pressure coring was conducted to recover gas hydrate-bearing sediments from two reservoir sections named Unit B and Unit D. A total of 34 cores were successfully recovered by 5 runs of a wireline deployed pressure coring system (CoreVault® System - Halliburton). The core analysis plan for this project is shown in Figure 1. Upon recovery, the pressure core autoclaves were transported from the Alaska North Slope to the Stratum Reservoir laboratory in Anchorage Alaska. To access the cores, they were first quenched in liquid nitrogen while still at high pressure in the core system autoclaves (Figure 1a). The cores were next removed from the pressure corer autoclaves with temperature control support from dry ice and stored under liquid nitrogen at atmospheric pressure. A total of 19 disturbed low-quality cores were processed for index property measurements, which included grain size and grain density analysis. Another 4 core samples were depressurized, trimmed, and core plugs were cut from each core and used to measure intrinsic permeabilities of host sediments (Figure 1). Unsteady-state permeability measurements were conducted on two samples to obtain relative water permeability (Rel.-Perm.) to gas and core scale Nuclear Magnetic Resonance (NMR) transverse relaxation time (T2) distribution measurements were performed to evaluate pore size distribution (Figure 1b). A total of 13 remaining high-quality cores with significant gas hydrate concentrations were preserved for advanced laboratory analysis. The National Institute of Advanced Industrial Science and Technology, as a part of the Japanese National Hydrate Research Program (MH21-S, funded by Ministry of Economy, Trade and Industry), received the 13 remaining high-quality core samples at their laboratories in Sapporo, Japan for advanced core analysis. High-resolution X-ray computed tomography (CT) was used to analyze the physical characteristics of the samples, which showed for the most part undisturbed lithological layers. Cores were lathed into cylindrical shapes and prepared for multi property measurements (Figure 1c). As a result, sediment from Unit D was characterized as silty-sand at ~37% porosity with ~80% gas hydrate saturation. An average hydration number n = 6.16 was measured for the recovered gas hydrate samples by Raman spectroscopy. An average intrinsic permeability of ~400 mD and in situ effective permeability (with hydrate) on the order of ~10 mD was measured for a total of five core samples. The Unit B recovered cores consisted of well sorted sand at ~40% porosity with ~95% gas hydrate saturation. An average intrinsic permeability of ~1 Darcy and in situ effective permeability on the order of ~30 mD was measured for the Unit B cores. Additional laboratory measurements yielded small permeability reductions due to porosity loss with increasing effective stress that simulated sediment consolidation along with depressurization in the highly permeable sandy sediment. The apparent limited change in porosity and permeability may be caused by the low compressibility of quartz sand grains in the recovered cores. X-ray diffraction (XRD) and thermal conductivity analysis also indicated a high quartz content within the recovered cores. Completed triaxial compression tests established internal friction angles based on the Mohr-Coulomb's failure criterion, which were calculated at 40° for hydrate-bearing sediment and 29.8° for hydrate free sediment.

Alaska↗
USGS2021

Alaska natural gas hydrate production testing: Test site selection, characterization and testing operations

This Interagency Agreement supports the U.S. Department of Energy (DOE) and its research partners in understanding, predicting, and testing the recoverability and potential production characteristics of onshore natural gas hydrate in the Greater Prudhoe Bay area on the Alaska North Slope (ANS: Prudhoe Bay, Kuparuk River, and Milne Point areas) or other areas deemed suitable by DOE and USGS for potential long-term production testing of gas hydrate. Researchers will accomplish these tasks by evaluating the occurrence and resource potential of the known gas hydrate accumulations in the Eileen trend. Geologic, geochemical, and geophysical (2-D and 3-D seismic surveys) data from northern Alaska and other data sources, including wireline and mud log surveys of wells of opportunity, will be used to assess the occurrence and nature of the known gas hydrate accumulations. The project involves two primary areas of effort: the geologic and engineering assessment of the Eileen gas-hydrate accumulation and support of DOE and its industry partners in evaluating, planning, and preparing for drilling and testing gas hydrate research wells in northern Alaska.

Alaska↗
USGS2022

A RADical approach to conservation in Alaska: Rapid climate change requires a new perspective

In Alaska, conservation areas are managed to promote the persistence of wild species, habitats, cultural resources, visitor experiences, and ecosystem services. Many conservation areas are managed by federal or state agencies, and have specific boundaries, missions, and legislative mandates. Many are also the domains of Indigenous and local people who derive livelihoods and cultural identity from these lands. These areas vary considerably as to whether they are managed solely for conservation versus other additional values. Myriad threats challenge the sustainability of these values, and conservation areas often exist to mitigate such threats. But regardless of jurisdiction, legal contexts, or historical impacts, all these places face challenges, unprecedented during human habitation, from one globally pervasive threat: anthropogenic climate change. Yes, ecosystems, including people who depend on them, have adapted to constant change in Alaska over most of the Holocene if not before (at least the last 18kyr). And this experience has conferred upon its constituents learned adaptive capacity, capabilities, and knowledges among the most flexible on the planet. We discuss the implications of the Resist, Accept, Direct adaptation framework in the context of conservation management in Alaska.

Alaska↗
USGS2023

Nearshore ecosystems in the Gulf of Alaska

Nearshore ecosystem monitoring in western Prince William Sound, Kenai Fjords National Park, Kachemak Bay, and Katmai National Park and Preserve has been conducted as a single Nearshore Component of the Gulf Watch Alaska program over the past five years (2017-2021). This program builds on the previous five years and continues, in many cases, decades of preceding research and monitoring. During the 2017-2021 period of Gulf Watch Alaska, we successfully collected data on more than 200 nearshore metrics across all regions. These metrics were explicitly selected because of their value as trophically-connected features that offer insights into causes of changes through bottom-up and top-down forces within the nearshore food web. During these past 5 years, this study design has been applied to documenting and understanding several perturbations, including the Pacific Marine Heatwave and loss of sea stars due to sea star wasting. Continued monitoring will allow for a better understanding of change in nearshore ecosystems across the Gulf of Alaska and the status of spill injured resources, including greater perspective on oil spill effects and recovery relative to other types of perturbations. This information will be critical for anticipating and responding to ongoing and future changes in the region, as well as providing data for understanding global-scale variation in marine environments.

Alaska↗
USGS2025

History of terrestrial ecosystem development in southern Alexander Archipelago, Alaska since the onset of deglaciation

This chapter focuses on reconstructing the history of vegetation development in southern Alexander Archipelago (AA) of southeast Alaska during and after deglaciation up to the present day. It also summarizes key findings from recent paleoceanographic research in the Gulf of Alaska to provide a detailed, well-dated record of late Quaternary climate changes for the region. Understanding the regional climate history contributes to the reconstruction of late Quaternary glacial history and the timing of deglaciation, as it establishes minimum limiting dates for possible human occupation of southeast Alaska and northern coastal British Columbia (BC). This regional climate history is essential for recognizing relationships between the timing of climate changes and major ecological changes, and subsequent cultural development and adaptations. The reconstructed vegetation history of southern Alexander Archipelago since the onset of deglaciation provides important insights into the resources available to the earliest settlers and how these resources changed over time. The vegetation history presented here is based on dated pollen records from five unpublished sites and two previously published sites from the region. These records establish the timing and nature of changing terrestrial ecosystems in the southern AA.

Alaska↗
USGS2013

Summit crater lake observations, and the location, chemistry, and pH of water samples near Mount Chiginagak volcano, Alaska: 2004-2012

Mount Chiginagak is a hydrothermally active volcano on the Alaska Peninsula, approximately 170 km south–southwest of King Salmon, Alaska (fig. 1). This small stratovolcano, approximately 8 km in diameter, has erupted through Tertiary to Permian sedimentary and igneous rocks (Detterman and others, 1987). The highest peak is at an elevation of 2,135 m, and the upper ~1,000 m of the volcano are covered with snow and ice. Holocene activity consists of debris avalanches, lahars, and lava flows. Pleistocene pyroclastic flows and block-and-ash flows, interlayered with andesitic lava flows, dominate the edifice rocks on the northern and western flanks. Historical reports of activity are limited and generally describe “steaming” and “smoking” (Coats, 1950; Powers, 1958). Proximal tephra collected during recent fieldwork suggests there may have been limited Holocene explosive activity that resulted in localized ash fall. A cluster of fumaroles on the north flank, at an elevation of ~1,750 m, commonly referred to as the “north flank fumarole” have been emitting gas throughout historical time (location shown in fig. 2). The only other thermal feature at the volcano is the Mother Goose hot springs located at the base of the edifice on the northwestern flank in upper Volcano Creek, at an elevation of ~160 m (fig. 2, near sites H1, H3, and H4). Sometime between November 2004 and May 2005, a ~400-m-wide, 100-m-deep lake developed in the snow- and ice-filled summit crater of the volcano (Schaefer and others, 2008). In early May 2005, an estimated 3 million cubic meters (3×106 m3) of sulfurous, clay-rich debris and acidic water exited the crater through tunnels at the base of a glacier that breaches the south crater rim. More than 27 km downstream, these acidic flood waters reached approximately 1.3 m above normal water levels and inundated a fertile, salmon-spawning drainage, acidifying the entire water column of Mother Goose Lake from its surface waters to its maximum depth of 45 m (resulting pH ~2.9), and preventing the annual salmon run in the King Salmon River. A simultaneous release of gas and acidic aerosols from the crater caused widespread vegetation damage along the flow path. Since 2005, we have been monitoring the crater lake water that continues to flow into Mother Goose Lake by collecting surface water samples for major cation and anion analysis, measuring surface-water pH of affected drainages, and photo-documenting the condition of the summit crater lake. This report describes water sampling locations, provides a table of chemistry and pH measurements, and documents the condition of the summit crater between 2004 and 2011. In September 2013, the report was updated with results of water-chemistry samples collected in 2011 and 2012, which were added as an addendum.

Alaska↗
USGS2014

Why the 1964 Great Alaska Earthquake matters 50 years later

Spring was returning to Alaska on Friday 27 March 1964. A two‐week cold snap had just ended, and people were getting ready for the Easter weekend. At 5:36 p.m., an earthquake initiated 12 km beneath Prince William Sound, near the eastern end of what is now recognized as the Alaska‐Aleutian subduction zone. No one was expecting this earthquake that would radically alter the coastal landscape, influence the direction of science, and indelibly mark the growth of a burgeoning state.

Alaska↗
USGS2001

Juvenile groundfish habitat in Kachemak Bay, Alaska, during late summer

We investigated the habitat of juvenile groundfishes in relation to depth, water temperature, and salinity in Kachemak Bay, Alaska. Stations ranging in depth from 10 to 70 m and with sand or mud-sand substrates were sampled with a small-meshed beam trawl in August-September of 1994 to 1999. A total of 8,201 fishes were captured, comprising at least 52 species. Most fishes (91%) had a total length < 150 mm and were in their juvenile stage. Overall, the most abundant fishes were the rock soles Lepidopsetta spp. and Pacific cod Gadus macrocephalus. Other common species (>5% of the total catch) were flathead sole Hippoglossoides elassodon, slim sculpin Radulinus asprellus, Pacific halibut Hippoglossus stenolepis, and arrowtooth flounder Atheresthes stomias. Depth accounted for most of the spatial variability in juvenile groundfish abundance, and neither temperature nor salinity was correlated with fish abundance. Juvenile groundfishes concentrated in either shallow (less than or equal to 20 m) or deep (50-70 m) water, with co-occurrence of some species between 30-40 m. Shallow fishes were the rock soles, Pacific halibut, and great sculpin Myoxocephalus polyacanthocephalus. Deep species were flathead sole, slim sculpin, spinycheek starsnout Bathyagonus infraspinatus, rex sole Glyptocephalus zachirus, tadpole sculpin Psychrolutes paradoxus, and whitebarred prickleback Poroclinus rothrocki. This 6-year study provides baseline data on relative abundance and distribution of juvenile groundfishes in Kachemak Bay and may provide a useful tool for predicting the presence of species in similar habitats in other areas of Alaska.

Alaska Fishery Research Bulletin↗
USGS2012

Migrated hydrocarbons in exposure of Maastrichtian nonmarine strata near Saddle Mountain, lower Cook Inlet, Alaska

Magoon and others (1980) described an 83-meter- (272-foot-) thick succession of Maastrichtian (Upper Cretaceous) conglomerate, sandstone, mudstone, and coal exposed on the south side of an unnamed drainage, approximately 3 kilometers (1.8 miles) east of Saddle Mountain in lower Cook Inlet (figs. 1 and 2). The initial significance of this exposure was that it was the first reported occurrence of nonmarine rocks of this age in outcrop in lower Cook Inlet, which helped constrain the Late Cretaceous paleogeography of the area and provided important information on the composition of latest Mesozoic sandstones in the basin. The Saddle Mountain section is thought to be an outcrop analog for Upper Cretaceous nonmarine strata penetrated in the OCS Y-0097 #1 (Raven) well, located approximately 40 kilometers (25 miles) to the south–southeast in Federal waters (fig. 1). Atlantic Richfield Company (ARCO) drilled the Raven well in 1980 and encountered oil-stained rocks and moveable liquid hydrocarbons between the depths of 1,760 and 3,700 feet. Completion reports on file with the Bureau of Ocean Energy Management (BOEM; formerly Bureau of Ocean Energy Management, Regulation and Enforcement, and prior to 2010, U.S. Minerals Management Service) either show flow rates of zero or do not mention flow rates. A fluid analysis report on file with BOEM suggests that a wireline tool sampled some oil beneath a 2,010-foot diesel cushion during the fl ow test of the 3,145–3,175 foot interval, but the recorded fl ow rate was still zero (Kirk Sherwood, written commun., January 9, 2012). Further delineation and evaluation of the apparent accumulation was never performed and the well was plugged and abandoned. As part of a 5-year comprehensive evaluation of the geology and petroleum systems of the Cook Inlet forearc basin, the Alaska Division of Geological & Geophysical Surveys obtained a research permit from the National Park Service to access the relatively poorly understood ‘Saddle Mountain exposure’ that is located in the Lake Clark National Park and Preserve. This work was done in cooperation with the Alaska Division of Oil & Gas and U.S. Geological Survey (USGS) research geologists. This report expands on Magoon and others’ (1980) description of the exposure, presents new data on sandstone composition and reservoir quality, presents new geochemical data on petroleum extracted from the outcropping sandstone, and describes oil-bearing correlative strata penetrated by the Raven well. Although the exposure is more than a kilometer (0.6 mile) east of Saddle Mountain (fig. 2), in this report we variously refer to it as the Saddle Mountain succession, Saddle Mountain section, or the rocks at Saddle Mountain underlain by Upper Jurassic strata of the Naknek Formation.

Alaska↗
USGS2014

Predicting the effects of climate change on ecosystems and wildlife habitat in northwest Alaska

We used a modeling framework and a recent ecological land classification and land cover map to predict how ecosystems and wildlife habitat in northwest Alaska might change in response to increasing temperature. Our results suggest modest increases in forest and tall shrub ecotypes in Northwest Alaska by the end of this century thereby increasing habitat for forest-dwelling and shrub-using birds and mammals. Conversely, we predict declines in several more open low shrub, tussock, and meadow ecotypes favored by many waterbird, shorebird, and small mammal species.

Alaska↗
USGS2003

Pop-up archival transmitting (PAT) tags: A method to investigate the migration and behavior of Pacific halibut ( Hippoglossus stenolepis ) in the Gulf of Alaska

Pop-up archival transmitting (PAT) tags provide a fisheries-independent method of collecting environmental preference data (depth and ambient water temperature) and migration distance. In this study, we evaluate the use of pop-up archival transmitting tags as a method to investigate demersal fish. We report the results from eight pop-up archival transmitting tagged Pacific halibut Hippoglossus stenolepis (from 107 to 165 cm FL) that were released in and around Resurrection Bay, Alaska. Commercial fishermen recovered three tags, while five tags transmitted data to Argos satellites. Horizontal migration was not consistent among fish as four Pacific halibut remained in the vicinity of release while the other four traveled up to 358 km from the release site. Vertical movement was not consistent among fish or over time; however, they spent most of their time at depths of 150 to 350 m. The minimum and maximum depths reached by any of the Pacific halibut were 2 m and 502 m, respectively. The fish preferred water temperatures of approximately 6°C, but experienced temperatures between 4.3 and 12.2°C. Light attenuation with depth prevented geolocation software and light sensing hardware from accurately estimating geoposition for the majority of days. The methods, adapted from investigations on large pelagic fish, proved to be effective for studying Pacific halibut in the northern Gulf of Alaska. PAT tags allowed us to obtain high accuracy locations of the fish at the end of the tag deployments as well as preliminary data to identify approximate seasonal locations and to characterize their depth and temperature characteristics. By using PAT tags, we will be able to ensure tag returns during the winter season (which is closed to fishing) and gain valuable biological information even if fish migrate large distances or to unexpected locations.

Alaska Fishery Research Bulletin↗