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At least 649 records · Page 36Linked to original sources
USGS2018

Hydrologic assessment of the Edwin B. Forsythe National Wildlife Refuge

The Edwin B. Forsythe National Wildlife Refuge (hereafter Forsythe refuge or the refuge) is situated along the central New Jersey coast and provides a mixture of freshwater and saltwater habitats for numerous bird, wildlife, and plant species. Little data and information were previously available regarding the freshwater dynamics that support the refuge’s ecosystems. In cooperation with the U.S. Fish and Wildlife Service, the U.S. Geological Survey conducted an assessment of the hydrologic resources and processes in the refuge and surrounding areas to provide baseline information for evaluating restoration projects and future changes in the hydrologic system associated with climate change and other anthropogenic stressors. During spring 2015, water levels were measured at groundwater and surface-water sites in and near the Forsythe refuge. These water-level measurements, along with surface-water elevations obtained from digital elevation models, were used to construct water-table-elevation and depth-to-water maps of the refuge and surrounding areas. Water-table elevations in the refuge ranged from sea level to approximately 65 feet above sea level; in most of the refuge, the water-table elevation was within 3 feet of sea level. The water-table-elevation map indicates that the direction of shallow groundwater flow at the regional scale is generally from west to east (much of it from the northwest to the southeast), and groundwater moves downgradient from the uplands toward major groundwater discharge areas consisting of coastal streams and wetlands. The depth to water is estimated to be less than 2 feet for approximately 86 percent of the refuge, which coincides closely with the percentage of wetland area in the refuge. Depth to water in excess of 20 feet below land surface is limited to higher elevation areas of the refuge. Streamflow data collected at continuous-record streamgages and partial-record stations within the Mullica-Toms Basin were summarized. Hydrograph separation of streamflow data for eight streamgages (2004–13) reveals that base flow accounts for 68–94 percent of streamflow in basins upstream from the refuge. The high base-flow inputs underscore the importance of groundwater as a source of freshwater that supports both the streams that flow into the refuge and the hydroecology of the contributing basins. Mean annual flow typically ranged from 1.7 to 2.1 cubic feet per second per square mile at the streamgages (2004–13) and between 1.2 and 2.3 cubic feet per second per square mile at the partial-record stations (1965–2015) but was notably greater or lower than these ranges at several stations. Mean annual water budgets were estimated for multiple regions of the refuge for 2004–13 using data compiled from nearby meteorological stations and groundwater flows derived from previously calibrated groundwater-flow models. Precipitation, groundwater recharge, and evapotranspiration were estimated from available data; direct runoff was calculated as the residual component of the water balance. Groundwater recharge rates were greatest in the upland-dominated areas of the refuge with estimates of 14.4 to 18.9 inches per year, which are equivalent to 30 to 40 percent of precipitation. Groundwater recharge rates were nearly zero in the central coastal areas because these areas are major groundwater discharge zones, the water table is near land surface, the subsurface is close to saturation and cannot accept much recharge, and much of the area is underlain by thick marsh deposits likely with low permeability. Estimates of evapotranspiration varied from about 26 inches per year in the upland-dominated areas to more than 35 inches per year in the coastal wetlands, equivalent to 55–79 percent of mean annual precipitation, indicating that it is a major component of the hydrodynamics of the Forsythe refuge. On the basis of output from previously calibrated groundwater-flow models, nearly all of the groundwater exiting the surficial aquifer system in the central coastal areas of the refuge is discharged to wetlands, which highlights the importance of groundwater discharge in supporting the ecosystems of the Forsythe refuge. In the central coastal areas, horizontal flow contributes more than 90 percent of the groundwater flow to the surficial system, indicating that the upbasin areas are a substantial source of water that ultimately discharges to streams and wetlands in the refuge.

New Jersey↗
USGS1993

Sediment export by ice rafting from a coastal Polynya, Arctic Alaska, U.S.A.

Strong offshore winds in early 1989 produced a shore polynya that reached along the entire north coast of Alaska and eastward beyond the mouth of the Mackenzie River in Canada. From January through April, this open water periodically exposed the shelf to sediment entrainment by suspension freezing. This process requires turbulence and supercooled water, which results in the formation of frazil and anchor ice. The resulting granular, sediment-laden ice was observed to extend over 100 km seaward of the outer continental shelf after having been advected offshore. It was sampled to determine sediment type and to quantify the particle load. The particle size was mainly silt and clay, with local admixtures of as much as 27% sand and coarser clasts. Melted ice samples contained from 31 to nearly 600 mg L -1 of sediment. Combining these data with over 400 km of shipboard and aerial observations, photographs, and computer analysis of a summer Landsat image, we estimated the sediment load per unit area of sea ice. Seaward of the shelf, in regions of dense pack ice, a conservatively estimated sediment load was over 289 t km -2 . Using a westward summer drift rate of 3 cm s -1 , the sediment transport through a 1-km-long north-south segment is 67,418 t during 3 mo. In terms of regional sediment dynamics (littoral transport estimated at 10,000 t during the same period) and sediment budget (continental denudation estimated at 10 t km -2 during the same period), this number is very significant. Benthic microfossils indicate that bottom sediment incorporated in the ice came from water depths ranging from the inner neritic seaward to 50 m. The large load of shelf-derived sediment observed seaward of the continental shelf indicates that ice entrainment and transport cause shelf erosion. Nothing is known about sediment release over the Arctic Ocean Basin from these pulses of dirty ice that are periodically introduced into the Transpolar Drift.

Alaska↗
USGS1972

Reconnaissance engineering geology of the Haines area, Alaska, with emphasis on evaluation of earthquake and other geologic hazards

The Alaska earthquake of March 27, 1964, brought into sharp focus the need for engineering geologic studies in urban areas. Study of the Haines area constitutes an integral part of an overall program to evaluate earthquake and other geologic hazards in most of the larger Alaska coastal communities. The evaluations of geologic hazards that follow, although based only upon reconnaissance studies and, therefore, subject to revision, will provide broad guidelines useful in city and land-use planning. It is hoped that the knowledge gained will result in new facilities being built in the best possible geologic environments and being designed so as to minimize future loss of life and property damage. Haines, which is in the northern part of southeastern Alaska approximately 75 miles northwest of Juneau, had a population, of about 700 people in 1970. It is built at the northern end of the Chilkat Peninsula and lies within the Coast Mountains of the Pacific Mountain system. The climate is predominantly marine and is characterized by mild winters and cool summers. The mapped area described in this report comprises about 17 square miles of land; deep fiords constitute most of the remaining mapped area that is evaluated in this study. The Haines area was covered by glacier ice at least once and probably several times during the Pleistocene Epoch. The presence of emergent marine deposits, several hundred feet above sea level, demonstrates that the land has been uplifted relative to sea level since the last major deglaciation of the region about 10,000 years ago. The rate of relative uplift of the land at Haines during the past 39 years is 2.26 cm per year. Most or all of this uplift appears to be due to rebound as a result of deglaciation. Both bedrock and surficial deposits are present in the area. Metamorphic and igneous rocks constitute the exposed bedrock. The metamorphic rocks consist of metabasalt of Mesozoic age and pyroxenite of probable early middle Cretaceous age. The igneous rocks consist of diorite and quartz diorite (tonalite) of Cretaceous age. Sedimentary rocks of Tertiary age may be present in the mapped area but are not exposed. The surficial deposits of Quaternary age,-have been divided into the following map units on the basis of time Of deposition, mode of origin, and grain size: (1) undifferentiated drift deposits, (2) outwash and Ice-contact deposits; (3) elevated fine-grained marine deposits, (4) elevated shore and delta deposits, (5) alluvial fan deposits, (6) colluvial deposits, (7) modern beach deposits, (8) Chilkat River flood-plain and delta deposits, and (9) manmade fill. Offshore deposits are described but are not mapped. Southeastern Alaska lies within the tectonically active belt that rims the northern Pacific Basin and has been active since at least early Paleozoic time. The outcrop pattern is the result of late Mesozoic and Tertiary deformational, metamorphic, and intrusive events. Large-scale faulting has been common. The two most prominent inferred fault systems in southeastern Alaska and surrounding regions are: (1) The Denali fault system and (2) the Fairweather-Queen Charlotte Islands fault system. In the general area of Haines, rocks of Mesozoic age northeast of Chilkat River have a simple monoclinal structure. Paleozoic-Mesozoic rocks southwest of Chilkat River are gently to rather complexly folded. Several major and numerous minor faults probably transect the general area of Haines but their exact location and character can only be inferred because their traces are coincident to the long axes of fiords and river valleys, where they are concealed by water or by valley-floor deposits. Inferred faults in or near the Haines mapped area are: (1) Chilkat River fault, (2) Chilkoot fault, (3) Takhin fault, and (4) faults in the saddle area at Haines. Southeastern Alaska lies in one of the two most seismically active zones in Alaska, a State where 6 percent of the world's shallow earthqua

Open-File Report↗
USGS1969

Effects of the earthquake of March 27, 1964, on various communities

The 1964 earthquake caused wide-spread damage to inhabited places throughout more than 60,000 square miles of south-central Alaska. This report describes damage to all communities in the area except Anchorage, Whittier, Homer, Valdez, Seward, the communities of the Kodiak group of islands, and communities in the Copper River Basin; these were discussed in previous chapters of the Geological Survey's series of reports on the earthquake. At the communities discussed herein, damage resulted primarily from sea waves of diverse origins, displacements of the land relative to sea level, and seismic shaking. Waves took all of the 31 lives lost at those communities; physical damage was primarily from the waves and vertical displacements of the land relative to sea level. Destructive waves of local origin struck during or immediately after the earthquake throughout much of Prince William Sound, the southern Kenai Peninsula, and the shores of Kenai Lake. In Prince William Sound, waves demolished all but one home at the native village of Chenega, destroyed homesites at Point Nowell and Anderson Bay, and caused varying amounts of damage to waterfront facilities at Sawmill Bay, Latouche, Port Oceanic, Port Nellie Juan, Perry Island, and western Port Valdez. The local waves, which ran up as high as 70 feet above tide level at Chenega and more than 170 feet in several uninhabited parts of the Sound, took nearly all of the lives lost by drowning at these communities. Destructive local waves that devastated shores of Anderson Bay and adjacent parts of western Port Valdez probably were generated primarily by massive submarine slides of glacial and fluvioglacial deposits ; the origin of the waves that caused damage at most of the other communities and at extensive uninhabited segments of shoreline is not known. At these places the most probable generative mechanisms are: unidentified submarine slides of unconsolidated deposits, and (or) the horizontal tectonic displacements, of 20 to more than 60 feet, that occurred in the Prince William Sound region during the earthquake. A train of long-period seismic sea waves that began about 20 minutes after the start of the earthquake inundated shores along the Gulf of Alaska coast to a maximum height of 35 feet above tide level. At the communities described, they virtually destroyed two logging camps at Whidbey Bay and Puget Bay on the south coast of the Kenai Peninsula, caused moderate damage to boat harbors and docks at Seldovia and Cordova, floated away some beach cabins in the Cordova area, and drowned two people, one at Point Whitshed near Cordora and one at the Cape Saint Elias Light Station. The seismic sea waves were generated by regional tectonic uplift of the sea floor on the Continental Shelf. Vertical tectonic displacements of the land relative to sea level that accompanied the earthquake affected virtually all the coastal communities. Tectonic subsidence of 5 to 6 feet, augmented locally by surficial subsidence of unconsolidated deposits required either the relocation or raising of structures at Portage, Girdwood, and Hope on Turnagain Arm. Shoreline submergence resulting from about 3½ feet of tectonic subsidence at Seldovia necessitated raising all waterfront facilities and the airstrip above the level of high tides. On the other hand, tectonic uplift of the land in the Prince Williams Sound region required deepening of the small-boat harbors at Cordora and Tatitlek, dredging of the waterways in the Cordova area, and lengthening of some docks or piers at Cordova, the Cape Hinchinbrook Light Station, and in Sawmill Bay. Significant structural damage from direct seismic shaking was largely confined to fluid containers and a pier facility near Kenai. Indirect damage from fissuring and differential settling of foundation mterials in the vicinity of the Cordova airfield mused damage to a building, underground utilities, an airfield fill, and the highway. Minor amounts of direct and indirect damage from seismic vibrations were sustained by most of the communities situated on unconsolidated deposits as far east as Yakutat, north to Fairbanks, and west to King Salmon. Except for a few cracked or toppled chimney, all the damage from shaking was confined to areas of thick, unconsolidated deposits. Foundation damage was almost entirely restricted to water-saturated unconsolidated deposits which, when liquefied by seismic shaking, could spread laterally toward free faces and (or) settle differentially through compaction.

Alaska↗
USGS2003

Aggradation of gravels in tidally influenced fluvial systems: Upper Albian (Lower Cretaceous) on the cratonic margin of the North American Western Interior foreland basin

Alluvial conglomerates were widely distributed around the margin of the Early Cretaceous North American Cretaceous Western Interior Seaway (KWIS). Conglomerates, sandstones, and lesser amounts of mudstones of the upper Albian Nishnabotna Member of the Dakota Formation were deposited as fill-in valleys that were incised up to 80 m into upper Paleozoic strata. These paleovalleys extended southwestward across present-day northwestern Iowa into eastern Nebraska. Conglomerate samples from four localities in western Iowa and eastern Nebraska consist mostly of polycrystalline quartz with lesser amounts of microcrystalline (mostly chert), and monocrystalline quartz. Previous studies discovered that some chert pebbles contain Ordovician-Pennsylvanian invertebrate fossils. The chert clasts analyzed in this study were consistent with these findings. In addition, we found that non-chert clasts consist of metaquartzite, strained monocrystalline quartz and 'vein' quartz from probable Proterozic sources, indicating that parts of the fluvial system's sediment load must have travelled distances of 400-1200 km. The relative tectonic stability of this subcontinent dictated that stream gradients were relatively low with estimates ranging from 0.3 to 0.6 m/km. Considering the complex sedimentologic relationships that must have been involved, the ability of low-gradient easterly-sourced rivers to entrain gravel clasts was primarily a function of paleodischarge rather than a function of steep gradients. Oxygen isotopic evidence from Albian sphaerosiderite-bearing paleosols in the Dakota Formation and correlative units from Kansas to Alaska suggest that mid-latitude continental rainfall in the Albian was perhaps twice that of the modern climate system. Hydrologic fluxes may have been related to wet-dry climatic cycles on decade or longer scales that could account for the required water supply flux. Regardless of temporal scale, gravels were transported during 'high-energy' pulses, under humid climatic conditions in large catchment areas. An overall rising sea level during the late Albian created accommodation space for the gravelly lithofacies equivalent to the Kiowa-Skull Creek rocks. As Western Interior sea level rose, regional stream gradients were reduced, resulting in regional fluvial aggradation. The conglomeratic lower parts of the Nishnabotna Member of the Dakota Formation formed the transgressive systems tract within an upper Albian sequence that is defined by two unconformities that can be traced from marine Kiowa strata in western Kansas northeastward into western Iowa (Brenner et al., 2000). Mud-draped cross-bedded sandstone bodies, laminated mudstone intervals, and vertical burrows in the lower strata of the Nishnabotna Member indicate that estuarine conditions existed at the mouths of the river system, and tidal effects were transmitted at least 200 km inland from the interpreted late Albian coast. These observations suggest that estuarine conditions stepped up the incised valleys as fluvial sediments aggraded in response to regional transgression that continued through the Late Albian. ?? 2003 Elsevier Ltd. All rights reserved.

Cretaceous Research↗
USGS2013

National assessment of geologic carbon dioxide storage resources: Results

In 2012, the U.S. Geological Survey (USGS) completed an assessment of the technically accessible storage resources ( TA SR ) for carbon dioxide (CO 2 ) in geologic formations underlying the onshore and State waters area of the United States. The formations assessed are at least 3,000 feet (914 meters) below the ground surface. The TA SR is an estimate of the CO 2 storage resource that may be available for CO 2 injection and storage that is based on present-day geologic and hydrologic knowledge of the subsurface and current engineering practices. Individual storage assessment units (SAUs) for 36 basins were defined on the basis of geologic and hydrologic characteristics outlined in the assessment methodology of Brennan and others (2010, USGS Open-File Report 2010–1127) and the subsequent methodology modification and implementation documentation of Blondes, Brennan, and others (2013, USGS Open-File Report 2013–1055). The mean national TA SR is approximately 3,000 metric gigatons (Gt). The estimate of the TA SR includes buoyant trapping storage resources ( B SR ), where CO 2 can be trapped in structural or stratigraphic closures, and residual trapping storage resources, where CO 2 can be held in place by capillary pore pressures in areas outside of buoyant traps. The mean total national B SR is 44 Gt. The residual storage resource consists of three injectivity classes based on reservoir permeability: residual trapping class 1 storage resource ( R1 SR ) represents storage in rocks with permeability greater than 1 darcy (D); residual trapping class 2 storage resource ( R2 SR ) represents storage in rocks with moderate permeability, defined as permeability between 1 millidarcy (mD) and 1 D; and residual trapping class 3 storage resource ( R3 SR ) represents storage in rocks with low permeability, defined as permeability less than 1 mD. The mean national storage resources for rocks in residual trapping classes 1, 2, and 3 are 140 Gt, 2,700 Gt, and 130 Gt, respectively. The known recovery replacement storage resource ( KRR SR ) is a conservative estimate that represents only the amount of CO 2 at subsurface conditions that could replace the volume of known hydrocarbon production. The mean national KRR SR , determined from production volumes rather than the geologic model of buoyant and residual traps that make up TA SR , is 13 Gt. The estimated storage resources are dominated by residual trapping class 2, which accounts for 89 percent of the total resources. The Coastal Plains Region of the United States contains the largest storage resource of any region. Within the Coastal Plains Region, the resources from the U.S. Gulf Coast area represent 59 percent of the national CO 2 storage capacity.

Circular↗
USGS2023

Mangrove habitat persistence and carbon vulnerability associated with increased nutrient loading and sea-level rise at Ding Darling National Wildlife Refuge (Sanibel Island, Florida, USA)

J.N. “Ding” Darling National Wildlife Refuge (DDNWR) is located on Sanibel Island along the southwestern coast of Florida, USA. Sanibel Island is heavily developed, but DDNWR provides protection for a large mangrove area that supports biodiversity and recreational opportunity. However, nitrogen (N) and phosphorus (P) eutrophication attributed to agriculture discharge along the Caloosahatchee River has affected the area’s aquatic habitat with algal blooms and may be causing untimely degradation of Sanibel’s mangrove forests. We launched a series of studies to understand how additional nutrient loading to the levels expected in the future might affect DDNWR’s mangrove resource. We experimentally fertilized selected mangrove forest areas with N fertilizer (+N; NH4) and P fertilizer (+P; P 2 O 5 ) for three years, and monitored soil surface elevation change, soil and pneumatophore CO 2 fluxes from respiration, mangrove tree sap flow from two species ( Avicennia germinans , Rhizophora mangle ), and individual tree and stand water use, from which we developed carbon (C) budgets for +N and +P vs. control simulations as applied to DDNWR’s 1112 ha mangrove area. Many of the measured response variables provided hints of subtle changes in response to +P rather than +N, which were compounded when scaled. From this, we found that additional P loading is expected to stimulate CO 2 uptake via net ecosystem exchange of C, likely pressing the system beyond metabolic capacity and leading to a projected 41% increase in lateral C export to the estuary. Additional lateral C export is concomitant to a reduction in vertical soil surface elevation with +P. Furthermore, an inability of DDNWR’s mangroves to bury additional P and a release of P-bound ions to lateral export may exacerbate estuarine eutrophication. We also modelled the effect of sea-level rise influences on DDNWR’s mangroves through 2100 using a soil cohort model (WARMER-Mangroves) and found that the mangroves may be resilient to current rates of sea-level rise into the future but may also be susceptible to moderate accelerations. Greater eutrophication could create additional vulnerabilities to mangrove submergence, especially to basin mangroves where P concentrations are high and already reducing soil surface elevations in some mangroves. Our results suggest that amelioration of current P concentrations and avoidance of additional P loading to Sanibel Island’s mangroves are management options to consider.

Florida↗
USGS2013

Modeling for the SAFRR Tsunami Scenario-generation, propagation, inundation, and currents in ports and harbors: Chapter D in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario

This U.S. Geological Survey (USGS) Open-File report presents a compilation of tsunami modeling studies for the Science Application for Risk Reduction (SAFRR) tsunami scenario. These modeling studies are based on an earthquake source specified by the SAFRR tsunami source working group (Kirby and others, 2013). The modeling studies in this report are organized into three groups. The first group relates to tsunami generation. The effects that source discretization and horizontal displacement have on tsunami initial conditions are examined in section 1 (Whitmore and others). In section 2 (Ryan and others), dynamic earthquake rupture models are explored in modeling tsunami generation. These models calculate slip distribution and vertical displacement of the seafloor as a result of realistic fault friction, physical properties of rocks surrounding the fault, and dynamic stresses resolved on the fault. The second group of papers relates to tsunami propagation and inundation modeling. Section 3 (Thio) presents a modeling study for the entire California coast that includes runup and inundation modeling where there is significant exposure and estimates of maximum velocity and momentum flux at the shoreline. In section 4 (Borrero and others), modeling of tsunami propagation and high-resolution inundation of critical locations in southern California is performed using the National Oceanic and Atmospheric Administration’s (NOAA) Method of Splitting Tsunami (MOST) model and NOAA’s Community Model Interface for Tsunamis (ComMIT) modeling tool. Adjustments to the inundation line owing to fine-scale structures such as levees are described in section 5 (Wilson). The third group of papers relates to modeling of hydrodynamics in ports and harbors. Section 6 (Nicolsky and Suleimani) presents results of the model used at the Alaska Earthquake Information Center for the Ports of Los Angeles and Long Beach, as well as synthetic time series of the modeled tsunami for other selected locales in southern California. Importantly, section 6 provides a comparison of the effect of including horizontal displacements at the source described in section 1 and differences in bottom friction on wave heights and inundation in the Ports of Los Angeles and Long Beach. Modeling described in section 7 (Lynett and Son) uses a higher order physical model to determine variations of currents during the tsunami and complex flow structures such as jets and eddies. Section 7 also uses sediment transport models to estimate scour and deposition of sediment in ports and harbors—a significant effect that was observed in southern California following the 2011 Tohoku tsunami. Together, all of the sections in this report form the basis for damage, impact, and emergency preparedness aspects of the SAFRR tsunami scenario. Three sections of this report independently calculate wave height and inundation results using the source specified by Kirby and others (2013). Refer to figure 29 in section 3, figure 52 in section 4, and figure 62 in section 6. All of these results are relative to a mean high water (MHW) vertical datum. Slight differences in the results are observed in East Basin of the Port of Los Angeles, Alamitos Bay, and the Seal Beach National Wildlife Refuge. However, given that these three modeling efforts involved different implementations of the source, different numerical wave propagation and runup models, and slight differences in the digital elevation models (DEMs), the similarity among the results is remarkable.

California↗
USGS2006

Application of Bacteroides fragilis phage as an alternative indicator of sewage pollution in Tampa Bay, Florida

Traditional fecal coliform bacterial indicators have been found to be severely limited in determining the significance and sources of fecal contamination in ambient waters of tropical and subtropical regions. The bacteriophages that infect Bacteroides fragilis have been suggested as better fecal indicators and at least one type may be human specific. In this study, the phages that infect B. fragilis host RYC2056 (RYC), including phage B56-3, and host ATCC 51477-HSP40 (HSP), including the human specific phage B40-8, were evaluated in the drainage basins of Tampa Bay, 7 samples (n=62), or 11%, tested positive for the presence of phages infecting the host HSP, whereas 28 samples, or 45%, tested positive using the host RYC. A survival study was also done to compare the persistence of phages B56-3 and B40-8 to MS2 coliphage in seawater at various temperatures. The decay rates for MS2 were 0.239 log 10 d −1 at 10°C, but increased to 0.896 at 20°C and 2.62 log 10 d −1 at 30°C. The two B. fragilis phages persisted much longer in the seawater compared to the coliphage and showed little variation between the temperatures. All sewage influents sampled from area wastewater treatment plants contained phages that infected the two B. fragilis hosts at levels from 1.2×10 4 to 1.11×10 5 pfu 100 ml −1 for host RYC and 67 to 350 pfu 100 ml −1 for host HSP. Of the 7 chlorinated effluent samples tested, 3 were positive for the presence of the phage using the host RYC and the phage enrichment method, with levels estimated to be <10 pfu 100 ml −1 . No phages were detected using the host HSP in the treated sewage effluent. Coliphages were found in 3 of the 7 effluent samples at a range of 30 to 1.2×10 3 pfu 100 ml −1 .

Florida↗
USGS2015

Slipstream: an early Holocene slump and turbidite record from the frontal ridge of the Cascadia accretionary wedge off western Canada and paleoseismic implications

Slipstream Slump, a well-preserved 3 km wide sedimentary failure from the frontal ridge of the Cascadia accretionary wedge 85 km off Vancouver Island, Canada, was sampled during Canadian Coast Guard Ship (CCGS) John P. Tully cruise 2008007PGC along a transect of five piston cores. Shipboard sediment analysis and physical property logging revealed 12 turbidites interbedded with thick hemipelagic sediments overlying the slumped glacial diamict. Despite the different sedimentary setting, atop the abyssal plain fan, this record is similar in number and age to the sequence of turbidites sampled farther to the south from channel systems along the Cascadia Subduction Zone, with no extra turbidites present in this local record. Given the regional physiographic and tectonic setting, megathrust earthquake shaking is the most likely trigger for both the initial slumping and subsequent turbidity currents, with sediments sourced exclusively from the exposed slump face of the frontal ridge. Planktonic foraminifera picked from the resedimented diamict of the underlying main slump have a disordered cluster of 14 C ages between 12.8 and 14.5 ka BP. For the post-slump stratigraphy, an event-free depth scale is defined by removing the turbidite sediment intervals and using the hemipelagic sediments. Nine 14 C dates from the most foraminifera-rich intervals define a nearly constant hemipelagic sedimentation rate of 0.021 cm/year. The combined age model is defined using only planktonic foraminiferal dates and Bayesian analysis with a Poisson-process sedimentation model. The age model of ongoing hemipelagic sedimentation is strengthened by physical property correlations from Slipstream events to the turbidites for the Barkley Canyon site 40 km south. Additional modelling addressed the possibilities of seabed erosion or loss and basal erosion beneath turbidites. Neither of these approaches achieves a modern seabed age when applying the commonly used regional marine 14 C reservoir age of 800 years (marine reservoir correction &Delta; R = 400 years). Rather, the top of the core appears to be 400 years in the future. A younger marine reservoir age of 400 years (&Delta; R = 0 years) brings the top to the present and produces better correlations with the nearby Effingham Inlet paleo-earthquake chronology based only on terrestrial carbon requiring no reservoir correction. The high-resolution dating and facies analysis of Slipstream Slump in this isolated slope basin setting demonstrates that this is also a useful type of sedimentary target for sampling the paleoseismic record in addition to the more studied turbidites from submarine canyon and channel systems. The first 10 turbidites at Slipstream Slump were deposited between 10.8 and 6.6 ka BP, after which the system became sediment starved and only two more turbidites were deposited. The recurrence interval for the inferred frequent early Holocene megathrust earthquakes is 460 &plusmn; 140 years, compatible with other estimates of paleoseismic megathrust earthquake occurrence rates along the subduction zone.

Slipstream Slump↗
USGS1959

Ground-water conditions and storage capacity in the San Joaquin Valley, California

The San Joaquin Valley includes roughly the southern two-thirds of the Great Central Valley of California. It is a broad structural trough surrounded by mountains. The northern part of the valley drains through the San Joaquin River northward to San Francisco Bay ; the southern part of the valley normally is a basin of interior drainage tributary to evaporation sumps in the trough of the valley, chiefly Tulare and Buena Vista Lake beds. In years of normal discharge most of the streamflow in the southern part of the valley not diverted for irrigation finds its way to Tulare and Buena Vista Lake beds. In the historic past, however, during years of heavy floods the low divide between Buena Vista and Tulare Lakes and the low divide between Tulare Lake and the San Joaquin River were overtopped and through-flowing drainage occurred over the full length of the valley. Because the Tulare Lake bed is the lowest point and also the largest sump, this whole basin of interior drainage is commonly referred to as the Tulare Lake drainage basin. Average annual precipitation ranges from more than 15 inches in the north- eastern part of the valley to less than 4 inches in the southwestern part. The precipitation decreases from north to south and from east to west across the valley. Streamflow, the critical quantity in the water supply, depends almost wholly on the amount and distribution of precipitation in the Sierra Nevada to the east. Much of this precipitation falls as snow, and the snowpack acts as a natural reservoir retaining much of the annual runoff until late spring and early summer. The mean seasonal runoff to the San Joaquin Valley is nearly 10 million acre- feet, of which about two-thirds is tributary to the San Joaquin River; the remaining third is tributary to Tulare Lake drainage basin. In 1952 about 8.5 million acre-feet of surface water was diverted for irrigation. Withdrawals of ground water for irrigation in 1952 approximated 7.5 million acre-feet. The surface of the San Joaquin Valley is not a featureless plain but is characterized by various types of physiography such as dissected uplands, low alluvial plains and fans, river flood plains and channels, and overflow lands and lake bottoms. The dissected uplands fringe the valley along its mountain borders. They are underlain by unconsolidated to semiconsolidated continental deposits of late Tertiary and early Quaternary age which have been moderately tilted and folded. The topography of these uplands ranges from deeply dissected hill land having a relief of several hundred feet to gently rolling land whose relief Is only a few feet. The low plains and fans border the dissected uplands along their valley- ward margins. They are generally fiat to gently undulating and featureless and are underlain by undeformed to slightly deformed alluvial deposits of Quaternary age. The river flood plains and channels lie along the San Joaquia and Kings Rivers in the axial part of the valley and along the major east-side streams. Where the rivers are incised below the general land surface, the flood plains are well defined; but in the axial trough of the valley, where the rivers are flanked by low-lying overflow lands, the flood-plain and channel deposits are confined to the stream channel and to the natural levees that slope away from the river. Overflow lands and lake bottoms include the historic beds of Tulare, Buena Vista, and Kern Lakes in the southern part of the valley, and the low-lying lands in the axial trough between the low alluvial plains and fans and the natural levees of the San Joaquin River and its major tributaries. They are level and featureless and are underlain by lake and swamp deposits of Recent age. The San Joaquin Valley is a great structural downwarp between the tilted block of the Sierra Nevada on the east and the complexly folded and faulted Coast Ranges on the we

Water Supply Paper↗
USGS1996

Depositional controls on coal distribution and quality in the Eocene Brunner Coal Measures, Buller Coalfield, South Island, New Zealand

The Buller Coalfield on the West Coast of the South Island, New Zealand, contains the Eocene Brunner Coal Measures. The coal measures unconformably overlie Paleozoic-Cretaceous basement rocks and are conformably overlain by, and laterally interfinger with, the Eocene marine Kaiata Formation. This study examines the lithofacies frameworks of the coal measures in order to interpret their depositional environments. The lower part of the coal measures is dominated by conglomeratic lithofacies that rest on a basal erosional surface and thicken in paleovalleys incised into an undulating peneplain surface. These lithofacies are overlain by sandstone, mudstone and organic-rich lithofacies of the upper part of the coal measures. The main coal seam of the organic-rich lithofacies is thick (10-20 m), extensive, locally split, and locally absent. This seam and associated coal seams in the Buller Coalfield are of low- to high-volatile bituminous rank (vitrinite reflectance between 0.65% and 1.75%). The main seam contains a variable percentage of ash and sulphur. These values are related to the thickening and areal distribution of the seam, which in turn, were controlled by the nature of clastic deposition and peat-forming mire systems, marine transgression and local tidal incursion. The conglomeratic lithofacies represent deposits of trunk and tributary braided streams that rapidly aggraded incised paleovalleys during sea-level stillstands. The main seam represents a deposit of raised mires that initially developed as topogenous mires on abandoned margins of inactive braidbelts. Peat accumulated in mires as a response to a rise in the water table, probably initially due to gradual sea-level rise and climate, and the resulting raised topography served as protection from floods. The upper part of the coal measures consists of sandstone lithofacies of flu vial origin and bioturbated sandstone, mudstone and organic-rich lithofacies, which represent deposits of paralic (deltaic, barrier shoreface, tidal and mire) and marine environments. The fluvial sandstone lithofacies accumulated in channels during a sea-level stillstand. The channels were infilled by coeval braided and meandering streams prior to transgression. Continued transgression, ranging from tidal channel-estuarine incursions to widespread but uneven paleoshoreline encroachment, accompanied by moderate basin subsidence, is marked by a stacked, back-stepping geometry of bioturbated sandstone and marine mudstone lithofacies. Final retrogradation (sea-level highstand) is marked by backfilling of estuaries and by rapid landward deposition of the marine Kaiata Formation in the late Eocene.

International Journal of Coal Geology↗
USGS2004

Quaternary tectonic setting of South-Central coastal California

Recent geodetic, geologic, and seismologic studies show that the south-central coast of California is a region of active Quaternary deformation. Northeast-directed crustal shortening is occurring in a triangular-shaped region between the Hosgri-San Simeon fault system on the west, the Southern Coast Ranges on the northeast, and the western Transverse Ranges on the south. We informally call this region the Los Osos domain. In this study, we conducted detailed geological, seismological, and geophysical investigations to characterize the nature and rates of deformation in the domain. Locations of active and potentially active faults and folds are compiled at a scale of 1:250,000 for the entire domain based primarily on onshore geologic data and offshore geophysical data. Crustal shortening in the domain is accommodated by a series of prominent northwest-trending reverse faults and localized folding. The reverse faults separate distinct structural blocks that have little or no internal deformation. Hangingwall blocks are being uplifted at rates of up to 0.2 mm/yr. Footwall blocks are either static or slowly subsiding at rates of 0.1 mm/yr or less, except for localized areas of concentrated subsidence directly adjacent to some faults. The cumulative rate of crustal shortening is about 1 to 2 mm/yr across the northern part of the domain based on observed geologic deformation. Cumulative shortening across the central and southern parts of the domain is poorly constrained by geologic data and may approach 2 to 3 mm/yr. Historical and instrumental seismicity generally are spatially associated with the uplifted blocks and bordering reverse faults to depths of about 10 km. Together with near-surface geological data and deeper crustal geophysical imaging that show high-angle faulting, the seismicity data indicate that the reverse faults probably extend to the base of the seismogenic crust. The base of the seismogenic crust may correspond with a mid-crustal detachment or decollement surface into which the reverse faults root. We speculate that the detachment may coincide, in part, with the top of a northeast-dipping slab of oceanic crust that extends beneath the western margin of the continent or with the brittle-ductile transition above the subducted slab. The Los Osos domain of north-northeast/south-southwest crustal shortening is structurally detached from the offshore Hosgri Fault Zones. Both the pattern and regional extent of deformation in the Los Osos domain contrast sharply with that of the offshore Santa Maria Basin. The basin is undergoing minor east-northeast/west-southwest crustal shortening at rates of less than 0.1 mm/yr and is moving northwestward at a rate of about 1 to 3 mm/yr relative to the Los Osos domain along the San Simeon and Hosgri Fault Zones. Geodetic data and the kinematics of north-northeast-directed crustal shortening of the Los Osos domain east of the Hosgri Fault Zone show that the rate and cumulative amount of right-slip along the Hosgri Fault Zone progressively decrease southward. Quaternary deformation within the Los Osos domain is related to distributed dextral simple shear associated with Pacific-North American plate motion. Paleomagnetic data show that clockwise rotation of the western Transverse Ranges has occurred along the southern boundary of the domain during the past 6 m.y. During this time, the Salinian crustal block, which forms the eastern boundary of the Los Osos domain, has remained relatively stable. Internal shortening of the Los Osos domain has accommodated the relative motions of these bordering crustal blocks, particularly the rotation of the western Transverse Ranges.

Bulletin↗
USGS1993

Occurrence and transport of agricultural chemicals in the Mississippi River basin, July through August 1993

Heavy rainfall and severe flooding in the upper Mississippi River Basin from mid-June through early August 1993 flushed extraordinarily large amounts of agricultural chemicals (herbicides and nitrate) into the Mississippi River, many of its tributaries, and, ultimately, the Gulf of Mexico. Even though extremely high streamflows were recorded during the flood in 1993, concentrations of herbicides, such as atrazine, alachlor, cyanazine, and metolachlor, were similar to the maximum concentrations measured during spring and summer 1991 and 1992. It was anticipated that the higher streamflows during the flood would dilute the concentrations of herbicides that are usually flushed into streams in late spring and summer. Instead, concentrations were similar to those measured during much lower flows, but the daily loads of herbicides transported in some reaches of the Mississippi River were higher than those measured in 1991 and 1992. The total atrazine load transported to the Gulf of Mexico from April through August 1993 (539,000 kilograms) was about 80 percent higher than that for the same period in 1991 and 235 percent higher than for the same period in 1992. The concentrations of atrazine and cyanazine in a few individual samples exceeded health-based limits for drinking water. However, because drinking-water regulations are based on the average of at least four quarterly samples, the annual average concentrations in the Mississippi River probably will not exceed these limits for 1993. Nitrate concentrations were similar to those measured during spring and summer 1991 and 1992. The loads of nitrate-nitrogen transported into the Gulf of Mexico during July and August 1993 were as much as 5,734 metric tons per day. These loads generally are similar to those measured in spring 1991 and 1992 but larger than those measured in summer 1991 and 1992. The total nitrate-nitrogen load transported to the Gulf of Mexico from April through August 1993 (827,000 metric tons) was about 37 percent larger than that for this same period in 1991 and 112 percent larger than that for the same period in 1992. The transport of extraordinarily high loads of nitrate and large amounts of fresh-water into the Gulf of Mexico during midsummer when primary production is highest could increase phytoplankton biomass and affect the gulf ecosystem along the Louisiana coast.

Mississippi River↗
USGS1952

Geology and hydrology of dam sites on the island of St. Croix, Virgin Islands

The Virgin Islands Corporation plans to build a series of small earth dams along some of the streams on the island of St. Croix, and field studies involving the selection and hydrology of possible sites was carried on by the Geological Survey during the months of August and September 1951. The island of St. Croix is the largest of the three principal islands of the Virgin. Islands group owned by the United States. It is about 21 miles long and 6 miles wide near the center and has an area of about 84 square miles. The northwestern part of the island contains mountains that reach a maximum altitude of 1,165 feet; the eastern half of the island is submountainous, containing some hills 600 to 800 feet in altitude. A coastal lowland area containing a few east-west trending marl and limestone hills characterizes the southwestern part of the island. The streams in the east half of the island and along the northwest coast are relatively short and are dry during most of the year. The streams draining the mountains from the south cross the coastal lowland in narrow and shallow ditches. The southeastward drainage from the eastern part of the mountainous area is diverted by Salt River and enters the sea on the north coast of the island. In the headwaters of some streams there is a small flow of water during most of the year that disappears below the surface upstream from or near the foot of the mountains. During most of the year the streams are essentially dry, flowing only after periods of heavy rainfall. In the coastal lowland near Bethlehem the average annual rainfall is about 46 inches. The east end of the island is relatively dry and the precipitation is estimated to be approximately 20 inches annually; the northwestern end of the island receives the most rainfall, probably more than 50 inches annually. Records show that from 1861 to 1876 there was deficient rainfall and the accumulated departure below normal was about 56 inches (fig. 2). From 1876 to 1920 there were numerous years of above -normal precipitation and the departure curve rose nearly 100 inches, to more than 40 inches above normal. From 1936 to 1950 there has been a more or less continuous decline in rainfall, amounting to a net deficiency of 72 inches, or from 44 inches above to 28 inches below normal. These changes in rainfall have a direct effect on the volume of stream flow an island. There are two general rock types on the island. The Mount Eagle volcanics and the intruded diorite are hard, dense crystalline rocks; the rock's underlying the coastal lowland and belt of hills between Salt River and Christiansted are sedimentary rocks, such as marl, limestone, sand, gravel, and clay. The permeability of the crystalline rocks and of the gray clay and basal conglomerate of the Jealousy formation is low and they are water bearing in few places. The Kingshill formation is composed of light-gray clay and light-yellow marl and included beds of limestone. In places the limestone contains solutional openings that yield water to wells. The alluvial sand, gravel, and clay that unconformably overlie the Kingshill marl include permeable beds that yield relatively large quantities of water to wells in a few places. It is evident from the small stream flow that by far the greatest part of the 46-inch average annual precipitation on the island is returned to the atmosphere through evaporation and transpiration. There are no records of stream flaw or ground-water flow from the drainage basins, but it is estimated that in some years the amount of water lost through evaporation and transpiration may be more than 90 percent of the total water available. It is proposed that a program be started and continued to collect and evaluate data on the hydrology of the island. The purpose of the dam-building program is to retain on the land a part of the water that formerly flowed to the sea and was of no beneficial use. Owing to the lack of hydrologic data, the maximum number of dams needed is not known; consequently, practically all possible sites on publicly owned land and sites that would benefit those lands were studied. Thus, 3 sites were selected in the valley near Little Grange that is a source of supply to the public-supply well field of Frederiksted; 19 sites were selected on or near property owned by the Virgin Islands Corporation; and 4 sites were selected along the Salt River above the public-supply well field of Christiansted. During most of the year the water table is at or below the beds of the streams; consequently, if permeable rocks underlie a pond or dam it is possible that there may be leakage from the pond to the water table. In general, leakage from dam sites underlain by crystalline rocks of the fount Eagle volcanics or clay of the Kingshill marl will be negligible, but leakage from sites underlain by limestone in the Kingshill marl or sand and gravel of the alluvium may be great. Potential leakage at each site selected is discussed.

Virgin Islands↗
USGS1947

Minor floods of 1938 in the North Atlantic States

Five noteworthy floods occurred during 1938 in the North Atlantic States. The first flood was in January, the others were in June, July, August, and September. The floods of January, June, and August were relatively local events in Connecticut, New Jersey, and New York, respectively. The floods of July and September were widespread, reaching from New Jersey and New York to New Hampshire in generally coincident locations. The flood of September, the most severe, is described in appropriate detail in Water-Supply Paper 867; the others in this volume are in separate sections arranged chronologically. Extraordinary floods in Connecticut during January 1938 resulted from a critical combination of warm rainfall and virtual overnight melting of the accumulated snowfall of winter. Seven small streams in central and western Connecticut rose to levels on January 25 higher than those reached during the great floods of March 1936. Crest discharge of these streams approximated 100 second-feet per square mile. Ice cover was loosened and sent downstream in recurrent jams. In general, the larger rivers did not attain extraordinary stages. The Connecticut River at Hartford peaked at a stage 3.6 feet above ordinary flood level. Direct damage by the flood was relatively small. Snow cover on January 20, at the beginning of the rains, varied from 0.25 inch along the coast to 2.75 inches water equivalent in the northern part of the State. Precipitation between January 24 and 26 exceeded 2.75 inches in only three small areas. Total supply as water in snow and precipitation did not exceed 4.8 inches over any tributary area. Maximum measured flood run-off was 2.7 inches. The flood of June 1938 in New Jersey was the immediate result of a 30-hour rainstorm on June 26-27 that centered along a line extending from Odessa, Del., to Milton, N. J. Storm rainfall exceeded 5 inches over a total area of 2,900 square miles. River stages in the central parts of the storm area rose to levels that approached and on a few rivers exceeded previous maxima of record. Damage was extensive throughout the storm area, especially in Burlington, N. J., where Sylvan Lake Dam failed. The highest rate of flow per unit of area measured was 88 second-feet per square mile. However, all peak discharges were exceeded during the later floods of 1938 or by the flood of September 1, 1940, which produced discharges over 1,000 second-feet per square mile in southern New Jersey. The maximum volume of direct runoff during the flood, expressed in mean depth in inches on the drainage area, was 2.1 inches. From July 17 to 25, 1938, there was an irregular series of rainstorms over the eastern seaboard that brought more than 10 inches of rain over an area of 2,000 square miles and more than 6 inches over 23,000 square miles. Nearly 14 inches of rain fell at Long Branch, N. J. Extraordinary floods occurred mainly in the smaller tributary streams. Damage to highways, homes, factories, and crops, particularly the tobacco co-op in Connecticut, was extensive. Crest discharges at 12 gaging stations exceeded those previously observed. Maximum rates of discharge varied from 601 second-feet per square mile for an area of 2.91 square miles in New Jersey to 35 second-feet per square mile for an area of 711 square miles in Connecticut. Antecedent soil moisture prior to the storm was probably normal or a little above. The maximum volume of direct runoff was 4.75 inches in Massachusetts, 5.6 inches in eastern Connecticut, 6.75 inches in the Catskill Mountain region of New York, and 4.95 inches in the Raritan River Basin of New Jersey. Infiltration indices from 0.09 .to 0.21 inch per hour were computed, such rates being within the range defined for basins in the same areas during the floods of September 1938. The flood of August 6-11, 1938, in the Catskill Mountain region of New York resulted from heavy rains with a maximum of 8 inches at two centers. Rainfall exceeded 3 inches over more than 3,000

Water Supply Paper↗
USGS2007

Subtidal sea level variability in a shallow Mississippi River deltaic estuary, Louisiana

The relative roles of river, atmospheric, and tidal forcings on estuarine sea level variability are examined in Breton Sound, a shallow (0.7 m) deltaic estuary situated in an interdistributary basin on the Mississippi River deltaic plain. The deltaic landscape contains vegetated marshes, tidal flats, circuitous channels, and other features that frictionally dissipate waves propagating through the system. Direct forcing by local wind stress over the surface of the estuary is minimal, owing to the lack of significant fetch due to landscape features of the estuary. Atmospheric forcing occurs almost entirely through remote forcing, where alongshore winds facilitate estuary-shelf exchange through coastal Ekman convergence. The highly frictional nature of the deltaic landscape causes the estuary to act as a low-pass filter to remote atmospheric forcing, where high-frequency, coastally-induced fluctuations are significantly damped, and the damping increases with distance from the estuary mouth. During spring, when substantial quantities of controlled Mississippi River inputs (q¯ = 62 m3 s¯ 1) are discharged into the estuary, upper estuary subtidal sea levels are forced by a combination of river and remote atmospheric forcings, while river effects are less clear downestuary. During autumn (q¯ = 7 m3 s-1) sea level variability throughout the estuary is governed entirely by coastal variations at the marine boundary. A frequency-dependent analytical model, previously used to describe sea level dynamics forced by local wind stress and coastal forcing in deeper, less frictional systems, is applied in the shallow Breton Sound estuary. In contrast to deeper systems where coastally-induced fluctuations exhibit little or no frictional attenuation inside the estuary, these fluctuations in the shallow Breton Sound estuary show strong frequency-dependent amplitude reductions that extend well into the subtidal frequency spectrum.

Louisiana↗
USGS2020

Detrital zircon age spectra of middle and upper Eocene outcrop belts, U.S. Gulf Coast region

Recently reported detrital zircon (DZ) data help to associate the Paleogene strata of the Gulf of Mexico region to various provenance areas. By far, recent work has emphasised upper Paleocene-lower Eocene and upper Oligocene strata that were deposited during the two episodes of the highest sediment supply in the Paleogene. The data reveal a dynamic drainage history, including (1) initial routing of western Cordilleran drainages towards the Gulf of Mexico in the Paleocene, (2) an eastward shift of the western continental divide, from the Jura-Cretaceous cordilleran arc to the eastern edge of the Laramide province after the Paleocene and (3) a southward shift, along the eastern Laramide province, of the headwaters of river systems draining to the Mississippi and Houston embayments at some time between the early Eocene and Oligocene. However, DZ characterisation of most (~20 Myr) of the middle Eocene-lower Oligocene section remains limited. We present 60 DZ age spectra, most of which are from the middle or upper Eocene outcrop belts, with 50–200-km spacing. We define six to eight distinct groups of DZ age spectra for middle and upper Eocene strata. Data from this and other studies resolve at least six substantial temporal changes in age spectra at various positions along the continental margin. The evolving age spectra constrain the middle and upper Eocene drainage patterns of large parts of interior North America. The most well-resolved aspects of these drainage patterns include (1) persistent rivers that flowed from erosional landscapes across the Paleozoic Appalachian orogen either into the low-lying Mississippi embayment or directly into the eastern Gulf; (2) at least during marine regressions, a trunk channel that likely flowed southward along the axial part of Mississippi Embayment and integrated tributaries from the east and west; and (3) rivers that flowed to the Houston embayment in the middle Eocene that likely originated in the Laramide province in central Colorado and southern Wyoming, as Precambrian basement highs in those source areas were being unroofed.

Gulf Coast region↗