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At least 1,405 records · Page 78Linked to original sources
USGS2011

Undiscovered hydrocarbon resources in the U.S. Gulf Coast Jurassic Norphlet and Smackover Formations

The U.S. Geological Survey has completed assessments of undiscovered technically recoverable oil and gas resources in the Jurassic Norphlet and Smackover formations of the onshore coastal plain and State waters of the U.S. Gulf Coast. The Norphlet Formation consists of sandstones and interbedded shales and siltstones deposited during a marine transgression. Along its northeast margin, deposition of the Norphlet was in alluvial fans, fluvial systems, and dune and clastic sabkha environments. Mudstones of the underlying Smackover Formation act as source rocks for Norphlet reservoirs. The Norphlet was divided into the following three assessment units (AUs): the Norphlet Salt Basins and Updip AU, the Norphlet Mobile Bay Deep Gas AU, and the Norphlet South Texas Gas AU. The lower part of the Smackover consists primarily of dark carbonate mudstone and argillaceous limestone deposited in low-energy environments, and is one of the Gulf of Mexico Basin’s major source rocks. The upper part of the Smackover is comprised primarily of grain-supported carbonates deposited in high-energy environments. The Smackover was divided into the following four AUs: the Smackover Updip and Peripheral Fault Zone AU, the Smackover Salt Basin AU, the Smackover South Texas AU, and the Smackover Downdip Continuous Gas AU. Although the Norphlet and Smackover formations have been the focus of extensive exploration and production, they probably still contain significant undiscovered oil and gas resources.

Alabama, Louisiana, Mississippi, Texas↗
USGS2010

Stratigraphy, age, and depositional setting of the Miocene Barstow Formation at Harvard Hill, central Mojave Desert, California

New detailed geologic mapping and geochronology of the Barstow Formation at Harvard Hill, 30 km east of Barstow, CA, help to constrain Miocene paleogeography and tectonics of the central Mojave Desert. A northern strand of the Quaternary ENE-striking, sinistral Manix fault divides the Barstow Formation at Harvard Hill into two distinct lithologic assemblages. Strata north of the fault consist of: a green rhyolitic tuff, informally named the Shamrock tuff; lacustrine sandstone; partially silicified thin-bedded to massive limestone; and alluvial sandstone to pebble conglomerate. Strata south of the fault consist of: lacustrine siltstone and sandstone; a rhyolitic tuff dated at 19.1 Ma (U-Pb); rock-avalanche breccia deposits; partially silicified well-bedded to massive limestone; and alluvial sandstone and conglomerate. Our U-Pb zircon dating of the Shamrock tuff by SHRIMP-RG yields a peak probability age of 18.7 ± 0.1 Ma. Distinctive outcrop characteristics, mineralogy, remanent magnetization, and zircon geochemistry (Th/U) suggest that the Shamrock tuff represents a lacustrine facies of the regionally extensive Peach Spring Tuff (PST). Here we compare zircon age and geochemical analyses from the Shamrock tuff with those of the PST at Stoddard Wash and provide new insight into the age of zircon crystallization in the PST rhyolite. Results of our field studies show that Miocene strata at Harvard Hill mostly accumulated in a lacustrine environment, although depositional environments varied from a relatively deep lake to a very shallow lake or even onshore setting. Rock-avalanche breccias and alluvial deposits near the base of the exposed section indicate proximity to a steep basin margin and detrital studies suggest a southern source for coarse-grained deposits; therefore, we may infer a southern basin-margin setting at Harvard Hill during the early Miocene. Our geochronology demonstrates that deposition of the Barstow Formation at Harvard Hill extended from before ~19.1 Ma until well after ~18.7 Ma, similar to timing of Barstow Formation lake deposition in the Calico Mountains but at least 3 million years older than comparable lacustrine facies in the Mud Hills type section. These observations are consistent with either of two paleogeographic models: westward transgression of lacustrine environments within a single large basin, or sequential development of geographically distinct eastern and western sub-basins.

California↗
USGS1976

The source of hydrothermal solutions at Puerto Maunabo and its bearing on the base-metal-potassium feldspar association in Puerto Rico

A quartz oligoclase porphyry exposed near Puerto Maunabo may provide evidence to further our understanding of the base-metal-potassium feldspar association known to occur in many of the porphyry-type copper deposits of Puerto Rico. The porphyry appears to be a magmatic differentiate on the border of the San Lorenzo batholith that may represent a source of mineralizing hydrothermal solutions. The porphyry intrudes an albitized quartz diorite border phase of the batholith that contains large roof pendants of metavolcanic rock. These roof pendants are mostly metamorphosed to greenschist metamorphic facies, but in the vicinity of Puerto Maunabo south of the porphyry, they reach amphibolite metamorphic facies; north of the porphyry, similar xenolithic lenses of metavolcanic rock appear to have been converted entirely to an oligoclase quartz felsite. The layered albitized quartz felsite has the same composition and texture as irregular veinlets in the albitized quartz diorite and as the groundmass in the porphyry. The K + ions arid basic ions of Fe +2 , Cu +2 , Mg +2 apparently were mobilized during final magmatic crystallization and then escaped as hydrothermal solutions that followed open conduits within a zone of structural weakness which also permitted the emplacement of the porphyry. The volcanic rock of Cerro Piedra Hueca, in contact with the albitized quartz diorite, and generally along strike west of the porphyry, has been altered to a quartz sericite rock entirely devoid of mafic silicates. This is the southeasternmost exposure of hydrothermally altered volcanic rock in the regional zone of northwest-trending faults that contains the principal porphyry-type copper deposits of Puerto Rico. The texture, mineralogy, and geologic environment of the porphyry at Puerto Maunabo are similar to those of the ore-bearing porphyries but differ in one important aspect. Most ore-bearing porphyries contain hydrothermal potassium feldspar and reddish-brown biotite intimately associated with the base-metal sulfides. In the porphyry of Puerto Maunabo, potassium feldspar is conspicuously absent, and only a trace of biotite is present; the only sulfide present is pyrite. The physical and chemical environment required to precipitate K + ions, either as potassium feldspar or biotite, apparently is very similar to that required to precipitate base-metal sulfides. At Puerto Maunabo, these conditions evidently did not prevail, and potassium and the base metals may have been carried in solution to a more favorable environment.

Puerto Maunabo↗
USGS2000

Estimating the impacts of oil spills on polar bears

The polar bear is the apical predator and universal symbol of the Arctic. They occur throughout the Arctic marine environment wherever sea ice is prevalent. In the southern Beaufort Sea, polar bears are most common within the area of the outer continental shelf, where the hunt for seals along persistent leads and openings in the ice. Polar bears are a significant cultural and subsistence component of the lifestyles of indigenous people. They may also be one of the most important indicators of the health of the Arctic marine environment. Polar bears have a late age of maturation, a long inter0brth period, and small liter sizes. These life history features make polar bear populations susceptible to natural and human perturbations. Petroleum exploration and extraction have been in progress along the coast of northern Alaska for more than 25 years. Until recently, most activity has taken place on the mainland or at sites connected to the shore by a causeway. In 1999, BP Exploration-Alaska began constructing the first artificial production island designed to transport oil through sub-seafloor pipelines. Other similar projects have been proposed to begin in the next several years. The proximity of oil exploration and development to principal polar bear habitats raises concerns, and with the advent of true off-shore development projects, these concerns are compounded. Contact with oil and other industrial chemicals by polar bears, through grooming, consumption of tainted food, or direct consumption of chemicals, may be lethal. The active ice where polar bears hunt is also where spilled oil may be expected to concentrate during spring break-up and autumn freeze-up. Because of this, we could expect that an oil spill in the waters and ice of the continental shelf would have profound effects on polar bears. Assessments of the effects of spills, however, have not been done. This report described a promising method for estimating the effects of oil spills on polar bears in the Arctic marine environment. It uses enough real data to illuminate necessary calculations and illustrate the value of the methods. The results and conclusions presented here are only examples of possible scenarios resulting from a new estimation method. Final assessment of the potential impacts to polar bears of an oil spill remains a work in progress.

Alaska, Northwest Territories, Yukon↗
USGS2002

Ongoing research experiments at the former Soviet nuclear test site in eastern Kazakhstan

Degelen mountain, located in Eastern Kazakhstan near the city of Semipalatinsk, was once the Soviets most active underground nuclear test site . Two hundred fifteen nuclear tests were conducted in 181 tunnels driven horizontally into its many ridges--almost twice the number of tests as at any other Soviet underground nuclear test site . It was also the site of the first Soviet underground nuclear test --a 1-kiloton device detonated on October 11, 1961. Until recently, the details of testing at Degelen were kept secret and have been the subject of considerable speculation. However, in 1991, the Semipalatinsk test site became part of the newly independent Republic of Kazakhstan ; and in 1995, the Kazakhstani government concluded an agreement with the U.S. Department of Defense to eliminate the nuclear testing infrastructure in Kazakhstan . This agreement, which calls for the "demilitarization of the infrastructure directly associated with the nuclear weapons test tunnels," has been implemented as the "Degelen Mountain Tunnel Closure Program." The U.S. Defense Threat Reduction Agency, in partnership with the Department of Energy, has permitted the use of the tunnel closure project at the former nuclear test site as a foundation on which to support cost-effective, research-and-development-funded experiments. These experiments are principally designed to improve U.S. capabilities to monitor and verify the Comprehensive Test Ban Treaty (CTBT), but have provided a new source of information on the effects of nuclear and chemical explosions on hard, fractured rock environments. These new data extends and confirms the results of recent Russian publications on the rock environment at the site and the mechanical effects of large-scale chemical and nuclear testing. In 1998, a large-scale tunnel closure experiment, Omega-1, was conducted in Tunnel 214 at Degelen mountain. In this experiment, a 100-ton chemical explosive blast was used to test technologies for monitoring the Comprehensive Nuclear Test Ban Treaty, and to calibrate a portion of the CTBT's International Monitoring System. This experiment has also provided important benchmark data on the mechanical behavior of hard, dense, fractured rock, and has demonstrated the feasibility of fielding large-scale calibration explosions, which are specified as a "confidence-building measure" in the CTBT Protocol. Two other large-scale explosion experiments, Omega-2 and Omega-3, are planned for the summer of 1999 and 2000. Like the Tunnel 214 test, the 1999 experiment will include close-in monitoring of near-source effects, as well as contributing to the calibration of key seismic stations for the Comprehensive Test Ban Treaty. The Omega-3 test will examine the effect of multiple blasts on the fractured rock environment.

Conference Paper↗
USGS2004

The depositional history of three freshwater lakes in north central Florida: Brooklyn Lake, Levy's Prairie, and Cowpen Lake

Florida has approximately 7800 lakes that are heavily concentrated in the north-central part of the state—a mantled karst terrain. Although much research has been conducted in Florida’s lakes, there is not much information on the sedimentary infill. The focus of this research is to define the sedimentary infill of three closely spaced lakes (Brooklyn Lake, Levys Prairie, and Cowpen Lake) in north-central Florida and determine the relative importance of the various sedimentary inputs and their associated processes. Interlake lithostratigraphy comparison helped determine if they experienced a similar depositional infilling history or a unique one. Twenty-three vibracores were taken (12 in Brooklyn Lake; 8 in Levys Prairie; 3 in Cowpen Lake) from which 331 sub-samples were analyzed for grain size, carbonate content, LOI index for total organic content, pollen content, mineralogy, and internal structures. Five sedimentary facies were defined in Brooklyn Lake, four in Levys Prairie, and three in Cowpen Lake. Using lithologic cross sections a depositional scenario was developed for each lake. Subaqueous and subaerial environments in conjunction with groundwater fluctuation and subsidence activity are key factors in lake development. The comparison of sediment infill of these three lakes reveals that Brooklyn Lake and Cowpen Lake are most similar in sediment facies content, basin morphology and the extent of subsidence depicted in the developmental scenarios, whereas, Levys Prairie is much different in sediment facies and basin morphology. A doubling in pine pollen from Brooklyn Lake and Levys Prairie indicate a change from drier to a wetter environment. This change is present in Sheelar Lake and Mud Lake and carbon14 dated at 7200 yrs BP and 5070+/-150 yrs BP (Watts and Stuiver, 1980, Watts, 1969 respectively). This suggests that Brooklyn Lake and Levys Prairie are older than 7200 yrs BP. Sediment infill from Brooklyn Lake, Levys Prairie and Cowpen Lake is conducive to understanding the depositional processes and environments that contributed to their development. Based on results and evidence presented in this study, it can be expected that lake development in a karst terrain will include subaqueous and subaerial intervals, and times of subsidence that can be recorded in the lake sediment.

Florida↗
USGS1969

Landscape esthetics: How to quantify the scenics of a river valley

There are an increasing number of bills before Congress that in one way or another affect the landscape or the environment. Each of these requires seemingly endless numbers of congressional hearings, which are recorded upon endless reams of paper. And if, for some reason, you happen to read the voluminous testimony surrounding one of these environment-affecting proposals, you will generally find a marked contrast between the volume and kind of information presented by those who are pressing for technical development - building a dam, constructing a highway, installing a nuclear power plant - and the testimony of those who either oppose the development or wish to alter it in some way. The developer usually employs numerical arguments, which tend to show that there is an economic benefit to be obtained by constructing something - whatever that something may be. The argument is usually expressed in terms of a "cost-benefit ratio." It is typically argued, for instance, that the construction cost of a given project will be repaid over a period of time and will yield a profit or a benefit in excess of the development costs by a ratio of, let us say, 1.2 to 1. The argument is further supported with great numbers of charts, graphs, tables, and additional figures. In marked contrast, those who favor protection of the environment against development are fewer in number, their statements are based on emotion or personal feelings, and they usually lack numerical information, quantitative data, and detailed computations. Perhaps this is the reason why this latter group seems to be continually fighting rearguard actions - losing battle after battle.

Natural History↗
USGS1996

Fish egg injection as an alternative exposure route for early life stage toxicity studies: Description of two unique methods: Chapter 4

In the environment, lipophilic contaminants such as halogenated aromatic hydrocarbons (HAHs, e.g., polychlorinated biphenyls, PCBs) and polycyclic aromatic hydrocarbons (PAHs, e.g., benzo[a]pyrene) readily bioaccumulate in fish, and the bioaccumulation of these lipophilic chemicals by adult fish may have significant consequences on the development and survival of their offspring. Halogenated and polycyclic aromatic hydrocarbons translocate from adult female body stores into eggs during oocyte maturation, and early life stages of fish are often more sensitive than adults to the toxicity of these chemicals. Thus, the presence of persistent, bioaccumulative contaminants in the environment may pose a risk to fish early life stage survival and ultimately reduce recruitment into the adult population. Typically, standard early life stage toxicity studies exposed embryos, larvae, and juveniles to graded concentrations of waterborne toxicants, and dose-response relationships are based on the concentrations of chemicals in the water. However, use of waterborne exposure to assess the toxicity of persistent, bioaccumulative contaminants, such as HAHs and PAHs, has two significant drawbacks. First, uptake of hydrophobic chemicals, such as HAHs and PAHs, into the developing embryo from water is not a significant route of exposure in the environment since concentrations of these chemicals freely dissolved in water are extremely low. Rather, maternal deposition into developing oocytes is the most significant source of these chemicals to the embryo. Second, the dose received by the target tissue, in this case the developing embryo, is the most accurate predictor of the toxic response, and since extrapolation from water concentrations of the chemical to egg concentrations is required, the exact dose received by the embryo can only be estimated, often with large uncertainty. Due to these drawbacks, it is important to develop an alternative exposure method that will directly expose the developing embryo without the need to chronically expose adult fish with subsequent natural deposition of hydrophobic chemicals into the oocytes. Fish egg injection provides this exposure route. Embryos are exposed directly after fertilization with known doses of contaminants, the dose is delivered prior to critical developmental events, and extrapolation of the dose received by the embryo is not needed. We have developed two unique fish egg injection methods as alternative routes of exposure for fish early life stage toxicity studies of lipophilic environmental contaminants. With either method, individual fish eggs are injected with a known dose of chemical. The first approach, a microinjection method, originally developed to assess the developmental toxicity of HAH congeners to early life stages of salmonids, utilizes micro-syringes, 30- gauge stainless steel injection needles, and micro- to nanoliter injection volume. The second approach, a nano-injection method, utilizes glass capillary micropipettes with 2 to 10 µm tips as injection needles, and nano- to picoliter injection volume, allowing injection of nearly any size of fish egg. Both of these egg injection methods allow an investigator to assess the toxicity of lipophilic environmental contaminants to early life stages of fish in a manner that realistically reflects environmental exposure and allows accurate quantitation of the dose to the developing embryo. These injection techniques, however, are not limited to use with only lipophilic chemicals. Since the developmental toxicity of many environmental contaminants ultimately depends on the dose received by the embryo, these egg injection methods could serve as a realistic exposure route in many fish early life stage toxicity studies.

Book chapter↗
USGS1969

Environmental impact of oil development in northern Alaska

It is reported that in the spring of 1969 a high official of one of the oil companies was flying over the area of oil development in the vicinity of Prudhoe Bay. He is quoted as saying "If the American people could see what we are doing to their land here, they would want to abolish the use of the reciprocating engine." The last really large area of wilderness in the United States is the' Brooks Range and the Arctic Coastal Plain which stretches from that range to the Arctic Ocean. The proving of the exploratory oil wells which have been drilled on the coastal plain in the vicinity of Prudhoe Bay makes it virtually certain that this heretofore mostly unknown country will rapidly and vigorously be exposed to a variety of changes caused by the influx of men and their equipment. Even within the first four months of 1969 the whole aspect of the central part of the region has been importantly changed by the drilling programs of several large oil companies. So suddenly was this change brought about that no long-range plans have been developed either to soften the effect of such development on the natural environment or even to record the progress of these effects. Yet the absence of a plan provides an inadvertent potential advantage in that there has' been no history of increasingly firm Federal policy which, in other places, has often made it difficult to take newly conceived action in line with the increasing societal interest in environmental preservation. The lack of firm Federal policy provides here a unique opportunity for the application of new rules and investigative techniques aimed at minimizing the adverse effects on the environment while5.at the same time, not unduly hindering the development of the natural resources. But the speed with which the changes are being wrought makes it imperative that the principles applicable here to environmental protection or preservation, be enunciated immediately and that from these principles flow farsighted regulations which reflect the new interest in combining resource development with environmental protection. The present report constitutes a brief summary of the conditions existing in northern Alaska in the spring of 1969, presenting some inferences on the environmental changes which can be expected in the future and offering some specific steps which, if taken immediately and positively, could greatly ameliorate the adverse effects of rapid development in the absence of positive steps for environmental protection. In that regard, then, this report is ephemeral in character because the conditions in northern Alaska will surely change with great rapidity. Considering the"fragility and sensitivity of the ecosystems existing there, the changes can be both harsh and permanent. Therefore, whatever value lies in the recommendations made here., the results of their application will depend on the promptness of their consideration, amendment, and application. Whatever form the actions might take for minimizing the harm to the environment, the urgency of the matter can hardly be overestimated.

Alaska↗
USGS2016

Groundwater science relevant to the Great Lakes Water Quality Agreement: A status report

When the Great Lakes Water Quality Agreement (GLWQA) was signed in 1972 by the Governments of Canada and the United States (the “Parties”) (Environment Canada, 2013a), groundwater was not recognized as important to the water quality of the Lakes. At that time, groundwater and surface water were still considered as two separate systems, with almost no appreciation for their interaction. When the GLWQA was revised in 1978 (US Environmental Protection Agency (USEPA), 2012), groundwater contamination, such as that reported at legacy industrial sites such as those at Love Canal near the Niagara River, was squarely in the news. Consequently, the potential impacts of contaminated groundwater from such sites on Great Lakes water quality became a concern (Beck, 1979), and Annex 16 was added to the agreement, to address “pollution from contaminated groundwater” (Francis, 1989). However, no formal process for reporting under this annex was provided. The GLWQA Protocol in 1987 modified Annex 16 and called for progress reports beginning in 1988 (USEPA, 1988). The Protocol in 2012 provided a new Annex 8 to address groundwater more holistically (Environment 2 Canada, 2013b). Annex 8 (Environment Canada, 2013b) commits the Parties to coordinate groundwater science and management actions; as a first step, to “publish a report on the relevant and available groundwater science” by February 2015 (this report); and to “identify priorities for science activities and actions for groundwater management, protection, and remediation…” The broader mandate of Annex 8 is to (1) “identify groundwater impacts on the chemical, physical and biological integrity of the Waters of the Great Lakes;” (2) “analyze contaminants, including nutrients in groundwater, derived from both point and non-point sources impacting the Waters of the Great Lakes;” (3) “assess information gaps and science needs related to groundwater to protect the quality of the Waters of the Great Lakes;” and (4) “analyze other factors, such as climate change, that individually or cumulatively affect groundwater’s impact on the quality of the Waters of the Great Lakes.” A binational Annex 8 Subcommittee was formed to lead efforts to fulfill the mandate of this annex (members listed on p. i of this report). In turn, this subcommittee has recruited a task team to prepare this report (listed as authors of each chapter). This report addresses all of the above four objectives, based on a compilation of the “relevant and available groundwater science.” Specifically, the second objective (to “analyze contaminants”) is addressed by incorporating information obtained in ongoing monitoring and research activities conducted by the Parties, and by various other members of the Great Lakes Executive Committee.

Illinois, Indiana, Michigan, Minnesota, New York, ↗
USGS1996

Hydrologic evaluation methodology for estimating water movement through the unsaturated zone at commercial low-level radioactive waste disposal site

This report identifies key technical issues related to hydrologic assessment of water flow in the unsaturated zone at low-level radioactive waste (LLW) disposal facilities. In addition, a methodology for incorporating these issues in the performance assessment of proposed LLW disposal facilities is identified and evaluated. The issues discussed fall into four areas: Estimating the water balance at a site (i.e., infiltration, runoff, water storage, evapotranspiration, and recharge); Analyzing the hydrologic performance of engineered components of a facility; Evaluating the application of models to the prediction of facility performance; and Estimating the uncertainty in predicted facility performance. An estimate of recharge at a LLW site is important since recharge is a principal factor in controlling the release of contaminants via the groundwater pathway. The most common methods for estimating recharge are discussed in Chapter 2. Many factors affect recharge; the natural recharge at an undisturbed site is not necessarily representative either of the recharge that will occur after the site has been disturbed or of the flow of water into a disposal facility at the site. Factors affecting recharge are discussed in Chapter 2. At many sites engineered components are required for a LLW facility to meet performance requirements. Chapter 3 discusses the use of engineered barriers to control the flow of water in a LLW facility, with a particular emphasis on cover systems. Design options and the potential performance and degradation mechanisms of engineered components are also discussed. Water flow in a LLW disposal facility must be evaluated before construction of the facility. In addition, hydrologic performance must be predicted over a very long time frame. For these reasons, the hydrologic evaluation relies on the use of predictive modeling. In Chapter 4, the evaluation of unsaturated water flow modeling is discussed. A checklist of items is presented to guide the evaluation. Several computer simulation codes that were used in the examples (Chapter 6) are discussed with respect to this checklist. The codes used include HELP, UNSAT-H, and VAM3DCG. To provide a defensible estimate of water flow in a LLW disposal facility, the uncertainty associated with model predictions must be considered. Uncertainty arises because of the highly heterogeneous nature of most subsurface environments and the long time frame required in the analysis. Sources of uncertainty in hydrologic evaluation of the unsaturated zone and several approaches for analysis are discussed in Chapter 5. The methods of analysis discussed include a bounding approach, sensitivity analysis, and Monte Carlo simulation. To illustrate the application of the discussion in Chapters 2 through 5, two examples are presented in Chapter 6. The first example is of a below ground vault located in a humid environment. The second example looks at a shallow land burial facility located in an arid environment. The examples utilize actual site-specific data and realistic facility designs. The two examples illustrate the issues unique to humid and arid sites as well as the issues common to all LLW sites. Strategies for addressing the analytical difficulties arising in any complex hydrologic evaluation of the unsaturated zone are demonstrated. The report concludes with some final observations and recommendations.

Report↗
USGS2018

Effect of climate change on disease spread in wildlife

A growing body of evidence indicates that climate change alone, or acting synergistically with current anthropogenic threats, is affecting the health of wild populations of aquatic and terrestrial wildlife. Measurable by-products of climate change include elevated atmospheric concentrations of greenhouse gases, higher average global temperatures; variations in global precipitation patterns, rising and warming oceans, altered hydrographs of rivers, and increased mid-continental drying during summer. These consequences affect the terrestrial environment through shifts in phenology, vegetation cover, and fire regimes. Warmer ocean temperatures, increased acidification, rise in sea levels, and reduction in sea ice cover are also leading to widespread ecological changes in marine systems. Wildlife populations face a variety of climate-related pressures, such as changes in animal distribution or density, limitation of food resources, and alteration to critical habitats. The increased potential for emergence and resurgence of diseases that are responsive to environmental conditions also has implications for wildlife populations. Shifts in temperature or other climatic factors may directly affect the incidence of disease in wildlife by altering host-pathogen interactions, promoting vector populations or allowing new ranges for vectors, or reducing development times for parasites. A number of examples from both field and laboratory studies have demonstrated a clear link between warming environments and disease spread. Many climate-related environmental changes also influence wildlife health indirectly. For example, increasing temperatures, in combination with shifts in rainfall and humidity, may aggravate current trends for water resource limitation and habitat degradation or destruction and lead to increased crowding of animal populations, thereby promoting transmission opportunities of pathogens within populations or across species. Although it may be difficult to disentangle the influences of other anthropogenic changes from the direct effects of warming, some ecosystems provide especially useful models for studying climate-related disease spread in wildlife. For example, the effects of climate change on parasite dynamics may be easily observed in the Arctic, where environmental changes are occurring rapidly, anthropogenic influences are relatively limited, and biodiversity is generally low. Marine ecosystems are also undergoing rapid rates of change and may be vulnerable to a variety of natural and anthropogenic perturbations. Although many factors affect the health of organisms in ocean environments, temperature has been clearly linked to an increase in disease prevalence among sessile organisms such as corals. In this chapter, we discuss observed and predicted changes to wildlife health resulting from climate change. Our review will not include all aspects of wildlife health, but will instead focus on established or suspected links between climate drivers and disease spread and discuss examples from the current literature. Here, we define disease spread to include: 1) change in geographical or altitudinal distribution of pathogens, parasites, and vectors and the diseases they cause; 2) change in prevalence or severity of disease; and 3) emergence of novel diseases. Additionally, because wildlife species serve as reservoirs for zoonotic diseases that affect both animals and humans, we include select examples of the effect of climate change on the capacity of wildlife to harbor and spread these disease agents.

Book chapter↗
USGS2019

Lithologies, ages, and provenance of clasts in the Ordovician Fincastle Conglomerate, Botetourt County, Virginia, USA

The Fincastle Conglomerate is an Ordovician polymictic, poorly sorted, matrix- and clast-supported cobble to boulder-rich conglomerate located just north of Fincastle, Botetourt County, VA. At least nine other cobble and boulder conglomerates are located in a similar stratigraphic position from Virginia to Georgia west of the Blue Ridge structural front. All except the Fincastle are dominated (~80%) by carbonate clasts; Fincastle clasts are much more varied and siliceous and it is this clast diversity that provides increased value for provenance and related studies. We have used a multidisciplinary approach that involves conodont analysis, sandstone petrography, in-situ outcrop clast characterization, optical petrography, electron-beam petrography and chemical analysis, and X-ray diffraction to provide data on lithologies, ages, and provenance. The size, roundness, and lithology of 1,656 clasts (> 1 cm) were measured in the field. Although, the clast lithology varies among the studied localities, the average lithology is sandstone and siltstone 12 %, vein quartz 17 %, limestone 31 %, low-grade quartzite/metasandstone 31 %, chert 6 %, and others 3 %. Dolomite, igneous, or high-grademetamorphic rock clastswere not identified in field study or in detailed laboratory analysis.Dolomite rhombs and authigenic albite feldsparwere observed in some limestone clasts. Quantitative petrographic data for the Fincastle sandstone clasts indicate tectonic environments from passive margin to transitional continental uplift, but the conglomeratematrixmodes have considerably less feldspar and plot in the foreland basin tectonic environment region. Proto-, para-, and euconodonts were identified from clast and matrix, but are long-ranging fauna indicating middle Cambrian toMiddle or Late Ordovician ages; color alteration index (CAI) for euconodonts varied from 3 to 3.5. The occurrence of well-rounded clasts including limestone suggests a nearby, high-energy environment, and that transport was rapid enough to preserve limestone before deposition into a foreland basin. The lack of igneous or high-grade metamorphic rocks clasts suggests that the erosional level sampled by the Fincastle Conglomerate did not include the underlying Grenville basement of igneous or high-grade metamorphic rocks.

Virginia↗
USGS2019

Flood-inundation mapping of a steep, gravel desert stream in Death Valley National Park, California

In desert landscapes, flooding can result in dramatic changes to streams. However, the frequency, magnitude, and geomorphic effects of floods in such environments are less understood compared to wetter environments (Tooth, 2000). In desert landscapes, steep slopes and sparse vegetation result in runoff and flashy flood peaks, often lasting for only a few hours. Many floods are the result of isolated, convective thunderstorms that cannot be predicted easily in advance and frequently occur at night. Therefore, direct observations or measurements of streamflow during floods often are limited, with data collection mostly occurring after the event. In ephemeral streams, limited vegetation within channels and on overbanks result in large stream velocity and higher probability for erosion during flooding. Moreover, flood occurrence in desert streams is often highly variable and some sites may go for years without streamflow, complicating flood frequency analyses. Finally, data sets in desert environments are often short and have few long-term, systematic collection sites.

California↗
USGS2001

Molluscan faunal distribution in Florida Bay, past and present: An integration of down-core and modern data

Statistical comparison of modern molluscan fauna to down-core molluscan assemblages in four cores elucidates changes in the Florida Bay ecosystem during the past 100 to 200 years. Fluctuations within molluscan faunal dominance and diversity patterns suggest a response to changing environmental conditions. Faunal dominance patterns indicate an increase in salinity in the northern transitional zone, and possibly the eastern portion of Florida Bay. Distinctive faunal shifts recorded at Russell Bank occur approximately between 1913 and 1933 and at Bob Allen mudbank between approximately 1900 and 1910. The period from approximately 1930 to 1980 within these cores shows rapid and dramatic fluctuations in species dominance and faunal richness. Beginning around 1980, the mussel Brachidontes exustus , which can tolerate diminished water quality and a wide range of salinities, increases in percent abundance in the upper portion of all four cores and becomes the dominant species at Russell Bank and Bob Allen Mudbank. While these fluctuations within assemblages are distinctive, they are not so profound that they represent a major shift in estuarine zonations within northern, eastern, and central Florida Bay during the past 100 to 200 years. The majority of the molluscan fauna that are present at the core sites today are generally present throughout the period of deposition. Fluctuations in the molluscan faunal record down-core primarily express changes in dominance and diversity within assemblages and do not reflect substantial changes in overall assemblages. It is these fluctuations in dominance and the appearance or disappearance of critical indicator species that are indicative of salinity changes. Understanding the dynamics of an ecosystem and the natural range of variation in the system over an extended period of time is a critical component of effective restoration. Analysis of the modern environment provides a means to interpret biological data preserved in cores, and to determine the physical and chemical variations in the environment indicated by the biota. Knowledge of the past provides the best insight to predicting the impact of future change on the environment.

Florida↗
USGS2020

Mapping, exploration, and characterization of the California continental margin and associated features from the California-Oregon border to Ensenada, Mexico

Priority Geographic Area: Both within and outside US Exclusive Economic Zone (EEZ). California continental margin. This area includes and continues south of the geographic area captured in the Watt et al. white paper. Description of Priority Area: The California continental margin, from the narrow shelf to abyssal depths, contains diverse seafloor features that influence benthic community types, biological connectivity, and is associated with significant seafloor geohazards. These complex features include marginal basins, depositional slopes, submarine canyons, ridges, and seamounts, and seep environments as a result of fluid seeps along active faults. Water column characteristics are variable, with steep gradients in current velocities, which influence sediment transport, from depositional fans (slow flow, muddy) to submarine canyons and seamounts (high currents, rocky, rugged terrain). These features and associated environments can influence the distribution of deep-sea habitats, including coral and sponge communities. South of the region described in the Watt et al. and Demopoulos et al. white papers, plentiful seeps occur from northern California down to the southern California Borderland. However, the underlying foundational geology associated with these seeps varies along the margin, changing with contrasting tectonic settings, from convergent tectonics to regions dominated by strike-slip faulting (Barry et al. 1996; Paull et al. 2008; Bernardo and Smith 2010; Maloney et al. 2015). For seeps located off southern California, the relationship to strike-slip fault systems may influence the distribution of seep fluid expulsion sites and associated seep habitats (Maloney et al. 2015; Grupe et al. 2015; Conrad et al., 2017), where transpression plays a key role in formation and localization of fluid seeps. Further exploration is required in order to understand these connections. Several submarine canyons intersect the shelf within this region, serving as important channels of energy and transport of sediment from shelf to slope depths. Canyons are typically associated with high currents, turbidity flows, steep and rugged terrain, and high food availability, all of which structures canyon communities and supports hotspots of biodiversity. Specific canyons along the California margin that have been well studied include Scripps and La Jolla Canyons off San Diego, and Monterey Canyon off Monterey, but many more remain relatively unexplored. Commercially important species of fish and invertebrates have been found associated with canyons, as well as deep-sea corals and sponges (e.g., Barry et al. 1996). However, in contrast to their Atlantic counterparts (e.g., through ACUMEN and ASPIRE campaigns) there has been a dearth of exploration and characterization of canyons along the California margin. A number of questions remain regarding canyon and slope wall stability and associated geohazards, plus, how the canyons connect and influence the broader regional biogeography of benthic communities is unknown. Due to their topography, seamounts along the California margin are characterized by steep slopes, large areas of rocky substrate, and high currents. Hydrological complexity is associated with seamounts given they impinge different watermasses, depending on depth range. This heterogeneity yields complex and diverse benthic communities, including commercially important fishes (e.g., Tracey et al., 2012). The geology of Davidson, Pioneer, San Juan, and Rodriquez Seamounts has received considerable study (e.g., Davis et al., 2010) but other seamounts are less known, including how they are biologically and ecologically connected. For example, research comparing the benthic communities associated with Rodriguez and San Juan Seamounts, located outside of the Channel Islands National Marine Sanctuary and within the proposed Chumash Heritage National Marine Sanctuary, to communities found within the sanctuary is critical for managing and protecting resources within the sanctuary and modifying sanctuary boundaries. Exploration would yield the data needed to delineate and characterize essential fish habitats, and deep-sea coral and sponge communities, thus directly connecting the utility of exploration and discovery to decision making. The southern California Borderland is a geomorphologically heterogeneous area created by a complex network of faults, containing deep basins separated by shallow ridges and islands. Persistent fault-related deformation has created complex features, such as exposure of scarps and uplift rocks/ridges, seeps, erosional terraces, hydrate mounds, and mud volcanoes that provide support for thriving benthic communities. That said, significant oxygen minimum zones and low aragonite saturation states persist within several of the basin environments, influencing energy flow, community ecology, and calcification. For example, the combined effects of hypoxia and acidification pose serious threats to marine organisms and biological resources along the California margin. Mapping and exploration of the extensive faults and fault scarps can help constrain historical earthquake activity. But many questions remain regarding how the underlying geology and geological processes have shaped the biological communities.

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USGS2022

Geologic setting and geomorphic history of La Botica and surrounding area

La Botica is located on the gently east-dipping marginal area between the high San Juan Mountains to the west and the San Luis Basin to the east in south-central Colorado. The site is positioned on a topographic bench perched about 70 to 80 m above La Jara Creek (figure 2.1), a tributary to the Rio Grande. The unique floral assemblage at La Botica has resulted in intermittent occupation over the last several thousand years. The physical environment supporting this assemblage is a result of Quaternary surface processes that have modified the underlying Tertiary bedrock. Underlying bedrock at the site consists of Oligocene to Pliocene volcanic and sedimentary deposits related to the Rio Grande rift and the San Juan volcanic locus of the Southern Rocky Mountains volcanic field. Local bedrock is mildly deformed by normal faulting and eastward tilting due to the onset of Oligocene extensional deformation and initial formation of the San Luis Basin. The geomorphic evolution and incision history of La Jara Creek are directly linked to middle to late Pleistocene evolution of the Rio Grande and to regional alpine glacial cycles over the last 500 k.y. (thousand years). Subsequent degradation of surrounding bedrock and development of mass-wasting deposits, such as landslides and talus slopes, have strongly influenced the incision history of La Jara Creek and the local environment at La Botica. In addition, local talus slopes and blockfields can host processes that actively modify the local environment, and these processes may have contributed to establishment of the floral assemblage.

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USGS2001

HAZUS 99 estimated annualized earthquake losses for the United States

Recent earthquakes around the world show a pattern of steadily increasing damages and losses. The increases are due primarily to two factors: 1) significant growth in urban areas that are prone to earthquakes; and 2) the vulnerability of the older building stock, even buildings that were constructed within the past twenty years. In the United States, earthquake risk has grown substantially with development, while the earthquake hazard has remained relatively constant. To understand the hazard, we study earthquake characteristics and locales in which they occur. To understand risk, we must include characteristics of the built environment in the locales where earthquakes occur, and we must assess potential damages to the built environment and the people who use it. That is a complex undertaking and one this study intends to advance. It is important to estimate the varying degrees of seismic risk throughout the United States because we need that understanding in order to make informed decisions on mitigation policies, priorities, strategies and funding levels—in both the public and private sectors. We can reduce earthquake losses to older buildings by rehabilitating them, and we can reduce earthquake losses in new buildings by applying seismic codes to their design and construction. However, decisions to spend money on either of those solutions require evidence of risk. In the absence of a nationally accepted criterion and methodology for comparing seismic risk across regions, a consensus on optimal mitigation approaches has been difficult to reach. We are all aware of regions with high hazard and high risk, such as Los Angeles, but there is growing recognition that some regions with low seismic hazard actually have high seismic risk, as is the case in New York City and Boston. This risk results, in part, from concentrations of buildings and infrastructure built without use of seismic codes or provisions. Additionally, mitigation policies and practices in the public and private sectors may not have been adopted because a community’s earthquake risk was not clearly demonstrated, and neither was the value of mitigation measures in reducing that risk. The low hazard/high risk problem exists in a number of areas in the U.S., where the infrequency of damaging earthquakes has been interpreted, wrongly, as lack of risk. While earth scientists work to increase knowledge about the hazard throughout the United States, structural engineers and other professionals work to enumerate the many factors that comprise risk. This study is one result of that endeavor. It is based on loss estimates generated by Hazards U.S. (HAZUS), a Geographic Information System (GIS)- based earthquake loss estimation tool, developed by the Federal Emergency Management Agency (FEMA) in cooperation with the National Institute of Building Sciences (NIBS). The HAZUS tool provides an approach to quantifying future earthquake losses that is national in scope, uniform in application, and comprehensive in its coverage of the built environment.

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