USGS Science⌕ Search

SEARCH · USGS Science

Results for “Atlantic Geology”

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

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
USGS2004

Issues of scale, location and geologic terrain related to Salt Lake City and Baltimore-Washington metropolitan areas

Planning and development of expanding metropolitan regions require consideration of earth science issues related to issues involving scale, space (location), geologic terrain and physiographic units, and information transfer. This paper explores these matters with examples from the Salt Lake City, Utah area and Mid-Atlantic region of Baltimore-Washington that include water supply and natural hazards (earthquakes, landslides, and sinkholes.) Information transfer methods using physiographic units at national, regional, local and site scales serve to communicate relevant geologic constraint and natural resource information.

Conference Paper↗
USGS2026

The surface elevation table and marker horizon technique: A protocol for measuring wetland elevation dynamics, narrative (Version 2.0)

The National Park Service (NPS), in response to the growing evidence and awareness of the effects of climate change on federal lands, determined that monitoring wetland elevation change is a top priority in North Atlantic Coastal parks (Stevens et al. 2010). As a result, the NPS Northeast Coastal and Barrier Network (NCBN) in collaboration with colleagues from the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA) have developed a protocol for monitoring wetland elevation change and other processes important for determining the viability of wetland communities. Although focused on North Atlantic Coastal parks, this document is applicable to all coastal and inland wetland regions. Wetlands exist within a narrow range of elevation that is influenced by local hydrologic conditions. For tidally influenced coastal wetlands, local hydrologic conditions may be changing as sea levels continue to rise. As sea level rises, coastal wetland systems may either a) build elevation to maintain favorable hydrologic conditions for their survival or b) become increasingly inundated beyond their physiological tolerance resulting in an eventual conversion to open water. A better understanding of these processes will help to determine the present and future viability of coastal wetlands managed by the NPS and can help address measures to ensure these communities exist into the future. This protocol provides the reader with instructions and guidelines on designing a monitoring plan or study to: Quantify elevation change in wetlands with the Surface Elevation Table (SET); understand the processes that influence elevation change, including vertical accretion (SET and Marker Horizon methods); survey the wetland surface and SET mark to a common reference datum to allow for comparing sample stations to each other and to local tidal datums; survey the SET mark to monitor its relative stability; and establish water level equipment to characterize the hydrology and tidal datums for a particular wetland site or sites. The protocol is divided into two documents: The narrative (this document) presents an overview of all aspects of monitoring wetland elevation dynamics, and a document of Standard Operating Procedures (SOPs) with detailed instructions on the design, installation, data collection, and data management in support of monitoring changes in wetland elevation.

Science Report↗
USGS2015

The surface elevation table and marker horizon technique: A protocol for monitoring wetland elevation dynamics

The National Park Service, in response to the growing evidence and awareness of the effects of climate change on federal lands, determined that monitoring wetland elevation change is a top priority in North Atlantic Coastal parks (Stevens et al, 2010). As a result, the NPS Northeast Coastal and Barrier Network (NCBN) in collaboration with colleagues from the U.S. Geological Survey (USGS) and The National Oceanic and Atmospheric Administration (NOAA) have developed a protocol for monitoring wetland elevation change and other processes important for determining the viability of wetland communities. Although focused on North Atlantic Coastal parks, this document is applicable to all coastal and inland wetland regions. Wetlands exist within a narrow range of elevation which is influenced by local hydrologic conditions. For coastal wetlands in particular, local hydrologic conditions may be changing as sea levels continue to rise. As sea level rises, coastal wetland systems may respond by building elevation to maintain favorable hydrologic conditions for their survival. This protocol provides the reader with instructions and guidelines on designing a monitoring plan or study to: A) Quantify elevation change in wetlands with the Surface Elevation Table (SET). B) Understand the processes that influence elevation change, including vertical accretion (SET and Marker Horizon methods). C) Survey the wetland surface and SET mark to a common reference datum to allow for comparing sample stations to each other and to local tidal datums. D) Survey the SET mark to monitor its relative stability. This document is divided into two parts; the main body that presents an overview of all aspects of monitoring wetland elevation dynamics, and a collection of Standard Operating Procedures (SOP) that describes in detail how to perform or execute each step of the methodology. Detailed instruction on the installation, data collection, data management and analysis are provided in this report and associated SOP’s. A better understanding of these processes will help to determine the present and future viability of coastal wetlands managed by NPS and can help address measures that will ensure these communities exist into the future.

Natural Resource Report↗
USGS1990

The geology of selected peat-forming environments in temperate and tropical latitudes

We studied peat in several geologic and climatic settings: (1) a glaciated terrain in cold-temperate Maine and Minnesota, U.S.A.; (2) an island in a temperate maritime climate in the Atlantic Ocean off the coast of Maine, U.S.A., where sea level is rising rapidly and changing the environment of peat accumulation; (3) swamps along the warm-temperate U.S. Atlantic and Gulf Coastal Plains, where sea level has changed often, thus creating sites for accumulation; and (4) in a tropical climate along the coast of Sarawak, Malaysia, and the delta of the Batang Hari River, Sumatra, Indonesia (Figs. 1 and 2). With the exception of the deposits on the Atlantic and Gulf Coastal Plains, most of the deposits described are domed bogs in which peat accumulation continued above the surface of the surrounding soil. The bogs of the U.S. Atlantic and Gulf Coastal Plains have almost level surfaces. All domed bogs are not entirely ombrotrophic (watered only from precipitation); multidomed bogs that rise from irregular or hilly surfaces may be crossed by streams that supply water to the bogs. The geologic processes or organic sedimentation, namely terrestrialization and paludification, are similar in all peat deposits considered here. Differences in geomorphology affecting the quantity and that quality of peat that has ash contents of less than 25%, which are desirable for commercial purposes, depend chiefly on: (1) high humidity, which is favorable to luxuriant growth of peat-forming vegetation; (2) a depositional setting that permits extensive accumulation relatively free from inorganic contamination from sea water and streams and from dust and volcanic ash; and (3) a stable regional water table that controls the rate of decomposition under aerobic conditions and protects the deposit against the ravages of fire. Differences in peat textures are due to the type of vegetation and to the degree of decomposition. The rate of decomposition is largely the result of the amount of oxidation and aerobic microbial activity. Stratigraphic distribution of various textures and amounts of inorganic components within a peat deposit is largely determined by the vertical positions occupied by peat-forming environments, such as pond, marsh, swamp and heath where vegetation accumulated, and the depth to zones of unoxygenated water. Peat also differs in the rate of accumulation. On the basis of carbon-14 dating, an estimated 8 m of peat in the tropical Batang Hari River deposit in Sumatra has been accumulating at the rate of about 1.5 m/1,000 yr, whereas peat in the cold-temperate deposit in Maine has been accumulating at the rate of 0.66 m/1,000 yr. Accumulation rates in domed deposits such as these are affected not only by factors controlling volume of biomass and aerobic decay but also by stream erosion and fires that remove peat. Such disconformities (see Fig. 2) within the deposit may be recognized by sudden vertical changes in degree of decomposition and/or the presence of charcoal. The trace-element content of peat deposits is affected by the environments of their settings. Samples of peat that have an ash content of less than 25% dry weight and that are from small, almost level swamp deposits along the Atlantic Coastal Plain of North Carolina were compared with similar samples from small domed bogs in Maine, a glaciated area. Samples from Nort Carolina, which are from deposits in thick fluvial and nearshore marine sediments far from the bedrock source, are generally higher in Ti, Cr and Pb. The Maine samples from deposits in glacial drift close to the bedrock source contain more Zn, Mn, P, Ca, Na and Fe. The kind and amount of trace elements within the deposits appear to relate largely to depositional setting, to kinds of bedrock source, and to the modes of transportation from source to peat swamp. Trace-element concentrations in the extensive Sumatra peat deposit, which represents a potentially commercial coal bed, are similar to those found in Appalachian coals except for As and Au, which are higher in the former. This similarity most likely implies that geochemical controls on mineral matter controlled the concentrations in both. Most peat deposits found in the world today are not precursors of economic coal beds because they are too local in extent, lack beds of commercial-quality peat greater than 6 m thick, and/or are too far from sea level to be rapidly by marine or marginal marine sediments before destruction by erosion and decomposition. However, the two domed deposits in Sarawak and Sumatra described above are parts of extensive, thick, low-sulfur, fuel-quality peat deposits, which have bases below the levels of rivers on coastal deltas. These are likely to be preserved in their lower part and to become precursors of tropical coal seams of potential economic importance. The lenticular and tabular peat deposits of the Atlantic and Gulf Coastal Plains, which have little chance of survival, have features resembling those in Tertiary peat deposits in alluvial settings of western North America. The quality, shape, and extent of modern and ancient peat deposits are controlled by the same factors - humidity, vegetation type, ground- and surface-water regimes, and physiographic and geologic setting. Thus, a study of modern peat deposits may help in studies of the areal distribution and the thickness and quality of ancient coal beds.

International Journal of Coal Geology↗
USGS2005

Late Neogene and Quaternary evolution of the northern Albemarle Embayment (mid-Atlantic continental margin, USA)

Seismic surveys in the eastern Albemarle Sound, adjacent tributaries and the inner continental shelf define the regional geologic framework and provide insight into the sedimentary evolution of the northern North Carolina coastal system. Litho- and chronostratigraphic data are derived from eight drill sites on the Outer Banks barrier islands, and the Mobil #1 well in eastern Albemarle Sound. Within the study area, parallel-bedded, gently dipping Miocene beds occur at 95 to > 160 m below sea level (m bsl), and are overlain by a southward-thickening Pliocene unit characterized by steeply inclined, southward-prograding beds. The lower Pliocene unit consists of three seismic sequences. The 55–60 m thick Quaternary section unconformably overlies the Pliocene unit, and consists of 18 seismic sequences exhibiting numerous incised channel-fill facies. Shallow stratigraphy (< 40 m bsl) is dominated by complex fill patterns within the incised paleo-Roanoke River valley. Radiocarbon and amino-acid racemization (AAR) ages indicate that the valley-fill is latest Pleistocene to Holocene in age. At least six distinct valley-fill units are identified in the seismic data. Cores in the valley-fill contain a 3–6 m thick basal fluvial channel deposit that is overlain by a 15 m thick unit of interlaminated muds and sands of brackish water origin that exhibit increasing marine influence upwards. Organic materials within the interlaminated deposits have ages of 13–11 cal. ka. The interlaminated deposits within the valley are overlain by several units that comprise shallow marine sediments (bay-mouth and shoreface environments) that consist of silty, fine- to medium-grained sands containing open neritic foraminifera, suggesting that this area lacked a fronting barrier island system and was an open embayment from ∼10 ka to ∼4.5 ka. Seismic data show that initial infilling of the paleo-Roanoke River valley occurred from the north and west during the late Pleistocene and early Holocene. Later infilling occurred from the south and east and is characterized by a large shoal body (Colington Island and Shoals) and adjacent inlet fill. Establishment of a continuous barrier island system across the bay-mouth resulted in deposition of the latest phase of valley-fill, characterized by estuarine organic-rich muds.

Albemarle Embayment↗
USGS1977

IPOD-USGS multichannel seismic reflection profile from Cape Hatteras to the Mid-Atlantic Ridge

A 3,400-km-long multichannel seismic-reflection profile from Cape Hatteras to the Mid-Atlantic Ridge was acquired commercially under contract to the National Science Foundation and the U.S. Geological Survey. These data show evidence for massive erosion of the continental slope, diapirs at the base of the continental slope, and mantle reflections beneath the Hatteras Abyssal Plain.

Geology↗
USGS2007

Monitoring Ground-Water Quality in Coastal Ecosystems

INTRODUCTION The Cape Cod National Seashore (CACO) extends along more than 70 km of Atlantic Ocean open-beach coastline and includes three large saltwater bays - Wellfleet Harbor, Nauset Marsh, and Pleasant Bay (fig. 1). CACO encompasses about 18,000 ha of uplands, lakes, wetlands, and tidal lands (Godfrey and others, 1999) including most habitats typical of the sandy coast in National seashores and parks extending southward from Massachusetts to Florida. In 1995, CACO was selected by the National Park Service (NPS) as a prototype park typifying the Atlantic and Gulf Coast biogeographic region for long-term coastal ecosystem monitoring. The U.S. Geological Survey (USGS) is currently (2007) assisting the NPS in the development of protocols for a Long-Term Coastal Ecosystem Monitoring Program at the CACO in Massachusetts. The overall purpose of the monitoring program is to characterize both natural and human-induced change in the biological resources of the CACO, over a time scale of decades, in the context of a changing global ecosystem.

Open-File Report↗
USGS1980

Outer Continental Shelf oil and gas activities in the mid-Atlantic and their onshore impacts: A summary report, November 1979: Update 1, June 30, 1980

The Master Water Data Index (MWDI) of the U.S. Geological Survey's National Water Data Exchange (NAWDEX) is a computerized data base which contains information about water data collected at specific sites. The data base identifies the organization collecting the data, the site location, the major types of data collected, the period of collection, and the frequency of measurement of major parameters for each type of data. This manual contains instructions for the encoding and keypunching of information for entry into the MWDI. Updates are published approximately every 6 months to provide new and revised information. A new Summary Report will be published only if a significant event occurs in the Region. This update covers new drilling operations in the Lease Sale 40 and 49 areas, information on the status of the upcoming Lease Sale 59, and an update on studies relevant to OCS-related planning activities. The organization of the update parallels that of the first Mid-Atlantic Summary Report. A copy of the Summary Report (USGS Open-File Report 80-17) can be obtained from the OCSIP. The address is listed on the reverse side of the title page.

Open-File Report↗
USGS2008

Impacts of Low-Flow and Stream-Temperature Changes on Endangered Atlantic Salmon - Current Research

Recent climate studies in New England and the northeastern United States have shown evidence of physical changes over time, including trends toward earlier snowmelt runoff, decreasing river ice, and increasing spring water temperatures. A U.S. Geological Survey (USGS) study funded by the National Global Warming and Wildlife Science Center will be investigating changes in summer low streamflows and stream temperatures and the potential effects of those changes on endangered Atlantic salmon populations. The study also will evaluate management options that would be most likely to mitigate the effects of any changes in streamflow and temperature.

Fact Sheet↗
USGS2000

The derivation of World Magnetic Model 2000

This report contains a detailed summary of the data used, the modelling techniques employed and the results obtained in the production of the World Magnetic Model 2000. This model is designed for use in air and sea navigation systems and is valid till 2005.0. The derivation of World Magnetic Model 2000 has been the joint responsibility of the British Geological Survey (BGS) and the United States Geological Survey (USGS). The World Magnetic Model is the standard model in UK Ministry of Defence and US Department of Defense, the North Atlantic Treaty Organization (NATO), and the World Hydrographic Office (WHO) navigation and attitude/heading referencing systems. It is also used widely in civilian navigation systems.

British Geological Survey Technical Report↗
USGS2019

Optimizing an inner-continental shelf geologic framework investigation through data repurposing and machine learning

The U.S. Geological Survey (USGS) and the National Oceanic Atmospheric Administration (NOAA) have collected approximately 5,400 km2 of geophysical and hydrographic data on the Atlantic continental shelf between Delaware and Virginia over the past decade and a half. Although originally acquired for different objectives, the comprehensive coverage and variety of data (bathymetry, backscatter, imagery and physical samples) presents an opportunity to merge collections and create high-resolution, broad-scale geologic maps of the seafloor. This compilation of data repurposes hydrographic data, expands the area of geologic investigation, highlights the versatility of mapping data, and creates new geologic products that would not have been independently possible. The data are classified using a variety of machine learning algorithms, including unsupervised and supervised methods. Four unique classes were targeted for classification, and source data include bathymetry, backscatter, slope, curvature, and shaded-relief. A random forest classifier used on all five source data layers was found to be the most accurate method for these data. Geomorphologic and sediment texture maps are derived from the classified acoustic data using over 200 groundtruth samples. The geologic data products can be used to identify sediment sources, inform resource management, link seafloor environments to sediment texture, improve our understanding of seafloor structure and sediment pathways, and demonstrate how ocean mapping resources can be useful beyond their original intent to maximize the footprint and scientific impact of a study.

Delaware, Maryland, Virginia↗