Geology topics

Arnell S. Forde

Publications and source records attributed to Arnell S. Forde.

At least 19 recordsLinked to original sources

USGS2025

Assessment of active sand volumes at Rockaway Beach and Fire Island in New York and Seven Mile Island in New Jersey

Between 2018 and 2023, the U.S. Geological Survey assessed shoreface sediment availability at three Atlantic Coast barrier island study sites in support of a National Fish and Wildlife Foundation project entitled, “Monitoring Hurricane Sandy Beach and Marsh Resilience in New York and New Jersey.” The three study sites are Seven Mile Island, New Jersey, Rockaway Beach peninsula, New York, and Fire Island, N.Y. Previously interpreted geologic boundaries from shoreface geophysical surveys and data from repeat bathymetric surveys at each of the study sites were integrated to quantify the active sediment volume, or the volume of sediment that could contribute to beach and shoreline behavior over annual to decadal time scales. This report describes the methods used to calculate these volumes and the variability of active sediment volume for each survey at the three study sites. Our data show that when shoreface volumes account for varying alongshore extent of each study site, Seven Mile Island and Rockaway Beach peninsula have about 1.5 times the active sediment volume measured at Fire Island.

New York, New Jersey↗

USGS2025

Geologic framework and Holocene sand thickness offshore of Seven Mile Island, New Jersey

The U.S. Geological Survey assessed the Quaternary evolution of Seven Mile Island, New Jersey, to quantify coastal sediment availability, which is crucial for establishing sediment budgets, understanding sediment dispersal, and managing coastlines. This report presents preliminary interpretations of seismic profiles, maps of Holocene sand thickness from the shoreline to 2 kilometers offshore, and tables quantifying the volume of available sediment along the coastal margin based on data collected during 2021 and 2022. The results reveal spatial variability in the thickness and cross-shore extent of Holocene sand. The study area was separated into northern, central, and southern zones by using underlying stratigraphy and geomorphic features. The characteristics and spatial extent of the Holocene sand deposit indicate that hydrodynamic processes contribute to its spatial variability. Northern Seven Mile Island contains the thickest deposits of Holocene sand that were formed by sediment bypass around the Townsends Inlet ebb-tidal delta. Specifically, swash bars have welded to the updrift end of Seven Mile Island and have formed thick deposits of Holocene sand that thicken landward and taper seaward. Despite their thickness, these deposits have the smallest cross-shore extent; therefore, northern Seven Mile Island has the smallest volume of Holocene sand of the three geomorphic zones. Central Seven Mile Island has the thinnest Holocene sand deposits because this section of the barrier island is outside the influence of ebb-tidal deltas. Southern Seven Mile Island has the greatest volumes of Holocene sand because of increased accommodation and deposition adjacent to the Hereford Inlet ebb-tidal delta. Even though tidal inlets exert variable influence on the three geomorphic zones, sediment is distributed fairly uniformly within each geomorphic zone; each of the three zones contains 31.05–36.48 percent of the volume of available Holocene sand.

New Jersey↗

USGS2024

Implications for the resilience of modern coastal systems derived from mesoscale barrier dynamics at Fire Island, New York

Understanding the response of coastal barriers to future changes in rates of sea level rise, sediment availability, and storm intensity/frequency is essential for coastal planning, including socioeconomic and ecological management. Identifying drivers of past changes in barrier morphology, as well as barrier sensitivity to these forces, is necessary to accomplish this. Using remote sensing, field, and laboratory analyses, we reconstruct the mesoscale (decades–centuries) evolution of central Fire Island, a portion of a 50 km barrier island fronting Long Island, New York, USA. We find that the configuration of the modern beach and foredune at Fire Island is radically different from the system's relict morphostratigraphy. Central Fire Island is comprised of at least three formerly inlet-divided rotational barriers with distinct subaerial beach and dune–ridge systems that were active prior to the mid-19th century. Varying morphologic states reflected in the relict barriers (e.g., progradational and transgressive) contrast with the modern barrier, which is dominated by a tall and nearly continuous foredune and is relatively static, except for erosion and drowning of its fringing marsh. We suggest that this state shift indicates a transition from a regime dominated by inlet-mediated gradients in alongshore sediment availability to one where human impacts exerted greater influence on island evolution from the late 19th century onward. The retention of some geomorphic capital in Fire Island's relict subaerial features combined with its static nature renders the barrier increasingly susceptible to narrowing and passive submergence. This may lead to an abrupt geomorphic state shift in the future, a veiled vulnerability that may also exist in other stabilized barriers.

New York↗

USGS2023

Evaluating oil and gas industry two-dimensional multichannel seismic data for use in near-surface assessment of geologic framework and potential marine minerals resources

Marine seismic reflection data acquired across the Gulf of Mexico during oil and gas exploration are available to the public through an online database archive. The data are archived as two-dimensional multichannel seismic data in two digital formats. The formats include image files in portable document format (PDF), and binary files in industry standard Society for Exploration Geophysicists revision Y (SEG-Y) format. Also included in the database are navigation files and acquisition information associated with the collection of the data. This study examines the data acquired within two geographic areas in the northern Gulf of Mexico. Although the seismic reflection data are acquired for oil and gas exploration many kilometers below the seafloor, this study focuses on the feasibility of using the data for near-surface geologic and seafloor morphologic studies (<100 meters below the seafloor). The report outlines the methodologies used to recover and process the data, including computer processing steps to convert the PDF imagery into SEG-Y format. The report includes two-dimensional profiles of the data to demonstrate the efficacy of the data in near-surface geologic studies. The study found that, for the two areas of interest, the seafloor reflectors in most of the available data are not resolvable. Although the data are readily available and computer processing can adequately image the uppermost reflectors of the seismic profiles, the resolution of the data in most cases are not suitable for near-surface geologic evaluations.

Alabama, Florida, Louisiana, Mississippi, Texas↗

USGS2023

Analysis of high-resolution single channel seismic data for use in sediment resource evaluation, eastern Texas and western Louisiana Continental Shelf, Gulf of Mexico

Shallow subsurface geologic data recorded as high-resolution seismic profiles are used to interpret the geology of coastal and marine systems. These data were originally recorded on paper rolls that are stored in geophysical archives. Data collection has since converted to entirely digital formats, yet the analog data are still useful for geologic interpretation. This report describes the process of recovering analog copies of seismic profiles from physical archives, electronically scanning, and converting them to industry-standard digital format. The recovered data are also reviewed and assessed for potential sediment resources. The data recovered in this study were collected from the Gulf of Mexico continental shelf offshore of East Texas and West Louisiana. The project is a collaborative study between the U.S. Geological Survey and the Bureau of Ocean Energy Management.

Louisiana, Texas↗

USGS2023

Reconstructing the geomorphic evolution and sediment budget history of a dynamic barrier island: Anclote Key, Florida

Decadal to centennial variations in sediment availability are a primary driver of coastal change within barrier systems. Models help explore how barrier morphology relates to past changes in magnitude of sediment availability, but this requires insights and validation from field efforts. In this study, we investigate the progradation of Anclote Key via its morphostratigraphy, a presently dynamic barrier on the Central Florida Gulf Coast. The results of our field efforts, including vibracores, ground-penetrating radar scans, and optically stimulated luminescence dating of sediments, reveal that Anclote Key has gone through at least two phases of sustained island-scale progradation, with an intervening episode of transgression followed by relative stability. We show that these shifts were likely driven by relatively small changes in shoreface sediment availability owing to the island’s limited accommodation and suggest that Anclote Key may have been relatively isolated from the alongshore sediment supply of nearby barriers prior to the late 20 th century.

Florida↗

USGS2022

Chandeleur Islands to Breton Island bathymetric and topographic datasets and operational sediment budget development: Methodology and analysis report

This study is part of the Coastal Protection and Restoration Authority (CPRA) Louisiana Barrier Island Comprehensive Monitoring (BICM) program. The goal of the BICM program is to provide long-term data on the barrier islands of Louisiana for monitoring change and assisting in coastal management. The BICM program uses historical data and acquires new data to map and monitor shoreline position, sediment properties, topography, bathymetry, and habitat. Since 2006, the U.S. Geological Survey (USGS) has collected geophysical and sedimentologic data across the Breton National Wildlife Refuge (BNWR) through the BICM program and collaborative USGS projects such as the Barrier Island Evolution Research project (under CPRA contract number 2000339324, BICM2–Chandeleurs TopoBathy DEM), which builds upon the previous BICM physical assessment of the BNWR outlined in a separate report. This project uses topographic and bathymetric data from three periods (1917–1922, 2006–2007, and 2013–2015) to develop digital elevation models (DEMs), measure elevation change, and calculate sediment budgets for the barrier island system. The sediment budget analysis, derived from the volumetric change between the three periods, is necessary for understanding sediment transport dynamics along barrier islands and providing information for effective coastal management. This report describes the methods used to acquire, process, and produce these products.

Louisiana↗

USGS2022

Chenier Plain region bathymetric and topographic datasets: Methodology report

The goal of the Louisiana Barrier Island Comprehensive Monitoring (BICM) program is to provide long-term data on coastal Louisiana for monitoring change and assisting in coastal management. This study (carried out under Coastal Protection and Restoration Authority contract number 2000339324, BICM2—Chenier TopoBathy DEM) builds upon the previous BICM physical assessment of the Chenier Plain region using bathymetric data from three periods (1930, 2007, and 2017) to develop digital elevation models for historical and current periods. In addition to bathymetric datasets, the study includes light detection and ranging elevation measurements along the coastline to produce elevation datasets for the 2007 and 2017 periods. This report describes the methods used to acquire, process, and produce these products.

Louisiana↗

USGS2021

Shoreface and Holocene sediment thickness offshore of Rockaway Peninsula, New York

During September and October 2019, the U.S. Geological Survey mapped the shoreface and inner continental shelf offshore of the Rockaway Peninsula in New York using high-resolution chirp seismic reflection and single-beam bathymetry geophysical techniques. The results from this study are important for assessing the Quaternary evolution of the Rockaway Peninsula and determining coastal sediment availability, which is crucial for establishing sediment budgets, understanding sediment dispersal, and managing coastlines. This report presents preliminary interpretations of seismic profiles and maps of shoreface and Holocene sediment thickness from the shoreline to about 2 kilometers offshore. The results indicate that shoreface and Holocene sediment thickness demonstrates zonal variability because of underlying geology and sediment availability. Based on geomorphic features and underlying stratigraphy, the study area is separated into west, west-central, east-central, and east zones. Holocene sediment, which includes the shoreface and seafloor features with positive morphology (for example, nearshore bars, ebb-tide deltas, and sorted bedforms), thickens to the west and may be related to accommodation and westward dip of the regional unconformity. Shoreface units, which are thought to represent the active volume of littoral sediment, are thickest in the west-central peninsula where the geologic base of the shoreface is deeper. Shoreface units with moderate thickness are in the western and eastern peninsula where there are positive morphological features (for example, deposits accumulating updrift from the jetty, ebb-tide deltas, and so on). The thinnest shorefaces are in the east-central Rockaway Peninsula because of less accommodation caused by the shoaling regional unconformity.

New York↗

USGS2018

Ground penetrating radar and differential global positioning system data collected in April 2016 from Fire Island, New York

Researchers from the U.S. Geological Survey (USGS) conducted a long-term coastal morphologic-change study at Fire Island, New York, prior to and after Hurricane Sandy impacted the area in October 2012. The Fire Island Coastal Change project objectives include understanding the morphologic evolution of the barrier island system on a variety of time scales (months to centuries) and resolving storm-related impacts, post-storm beach response, and recovery. In April 2016, scientists from the USGS St. Petersburg Coastal and Marine Science Center conducted geophysical and sediment sampling surveys on Fire Island to characterize and quantify spatial variability in the subaerial geology with the goal of subsequently integrating onshore geology with other surf zone and nearshore datasets. This report, along with the associated USGS data release , serves as an archive of ground penetrating radar (GPR) and post-processed differential global positioning system (DGPS) data collected from beach and back-barrier environments on Fire Island, April 6–13, 2016 (USGS Field Activity Number 2016-322-FA). Data products, including unprocessed GPR trace data, processed DGPS data, elevation-corrected subsurface profile images, geographic information system files, and accompanying Federal Geographic Data Committee metadata are available for download.

New York↗

USGS2018

Chirp subbottom profile data collected in 2015 from the northern Chandeleur Islands, Louisiana

As part of the Barrier Island Evolution Research project, scientists from the U.S. Geological Survey (USGS) St. Petersburg Coastal and Marine Science Center conducted a nearshore geophysical survey around the northern Chandeleur Islands, Louisiana, in September 2015. The objective of the project is to improve the understanding of barrier island geomorphic evolution, particularly storm-related depositional and erosional processes that shape the islands over annual to interannual time scales (1–5 years). Collecting geophysical data can help researchers identify relations between the geologic history of the islands and their present day morphology and sediment distribution. High-resolution geophysical data collected along this rapidly changing barrier island system can provide a unique time-series dataset to further the analyses and geomorphological interpretations of this and other coastal systems, improving our understanding of coastal response and evolution over medium-term time scales (months to years). Subbottom profile data were collected in September 2015 offshore of the northern Chandeleur Islands, during USGS Field Activity Number 2015-331-FA. Data products, including raw digital chirp subbottom data, processed subbottom profile images, survey trackline map, navigation files, geographic information system data files and formal Federal Geographic Data Committee metadata, and Field Activity Collection System and operation logs are available for download.

Louisiana↗

USGS2017

Digitized analog boomer seismic-reflection data collected during U.S. Geological Survey cruises Erda 90-1_HC, Erda 90-1_PBP, and Erda 91-3 in Mississippi Sound, June 1990 and September 1991

The U.S. Geological Survey (USGS) Coastal and Marine Geology Program has actively collected geophysical and sedimentological data in the northern Gulf of Mexico for several decades, including shallow subsurface data in the form of high-resolution seismic-reflection profiles (HRSP). Prior to the mid-1990s most HRSP data were collected in analog format as paper rolls of continuous profiles up to 25 meters long. A large portion of this data resides in a single repository with minimal metadata. As part of the National Geological and Geophysical Data Preservation Program, scientists at the USGS St. Petersburg Coastal and Marine Science Center are converting the analog paper records to digital format using a large-format continuous scanner. This report, along with the accompanying USGS data release (Bosse and others, 2017), serves as an archive of seismic profiles with headers, converted Society of Exploration Geophysicists Y format (SEG-Y) files, navigation data, and geographic information system data files for digitized boomer seismic-reflection data collected from the Research Vessel (R/V) Erda during two cruises in 1990 and 1991. The Erda 90-1 geophysical cruise was conducted in two legs. The first leg included seismic data collected from the Hancock County region of the Mississippi Sound (Erda 90-1_HC) from June 4 to June 6, 1990. The second leg included seismic data collected from the Petit Bois Pass area of Mississippi Sound (Erda 90-1_PBP) from June 8 to June 9, 1990. The Erda 91-3 cruise occurred between September 12 and September 23, 1991, and surveyed the Mississippi Sound region just west of Horn Island, Mississippi.

Data Series↗

USGS2017

Nearshore sediment thickness, Fire Island, New York

Investigations of coastal change at Fire Island, New York (N.Y.), sought to characterize sediment budgets and determine geologic framework controls on coastal processes. Nearshore sediment thickness is critical for assessing coastal system sediment availability, but it is largely unquantified due to the difficulty of conducting geological or geophysical surveys across the nearshore. This study used an amphibious vessel to acquire chirp subbottom profiles. These profiles were used to characterize nearshore geology and provide an assessment of nearshore sediment volume. Two resulting sediment-thickness maps are provided: total Holocene sediment thickness and the thickness of the active shoreface. The Holocene sediment section represents deposition above the maximum flooding surface that is related to the most recent marine transgression. The active shoreface section is the uppermost Holocene sediment, which is interpreted to represent the portion of the shoreface thought to contribute to present and future coastal behavior. The sediment distribution patterns correspond to previously defined zones of erosion, accretion, and stability along the island, demonstrating the importance of sediment availability in the coastal response to storms and seasonal variability. The eastern zone has a thin nearshore sediment thickness, except for an ebb-tidal deposit at the wilderness breach caused by Hurricane Sandy. Thicker sediment is found along a central zone that includes shoreface-attached sand ridges, which is consistent with a stable or accretional coastline in this area. The thickest overall Holocene section is found in the western zone of the study, where a thicker lower section of Holocene sediment appears related to the westward migration of Fire Island Inlet over several hundred years.

New York↗

USGS2016

Raw and processed ground-penetrating radar and postprocessed differential global positioning system data collected from Assateague Island, Maryland, October 2014

Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center acquired sediment cores, sediment surface grab samples, ground-penetrating radar (GPR) and Differential Global Positioning System (DGPS) data from Assateague Island, Maryland, in October 2014. The objectives were to identify washover deposits in the stratigraphic record to aid in understanding barrier island evolution. This report serves as an archive of GPR and DGPS data collected from Assateague Island in October 2014. Data products, including raw GPR and processed DGPS data, elevation corrected GPR profiles, and accompanying Federal Geographic Data Committee metadata can be downloaded from the Data Downloads page.

Maryland↗

USGS2016

Archive of Digital Chirp Subbottom Profile Data Collected During USGS Cruise 14BIM05 Offshore of Breton Island, Louisiana, August 2014

From August 11 to 31, 2014, the U.S. Geological Survey ( USGS ), in cooperation with the U.S. Fish and Wildlife Service ( USFWS ), conducted a geophysical survey to investigate the geologic controls on barrier island framework and long-term sediment transport offshore of Breton Island, Louisiana as part of a broader USGS study on Barrier Island Mapping ( BIM ). Additional details related to this activity can be found by searching the USGS's Coastal and Marine Geoscience Data System (CMGDS), for field activity 2014-317-FA (also known as 14BIM05). These surveys were funded through the USGS Coastal and Marine Geology Program ( CMGP ) and the Louisiana Outer Coast Early Restoration Project. This report serves as an archive of unprocessed digital chirp subbottom data, trackline maps, navigation files, Geographic Information System ( GIS ) files, Field Activity Collection System ( FACS ) logs, and formal Federal Geographic Data Committee ( FGDC ) metadata. Gained digital images of the seismic profiles are also provided. Refer to the Abbreviations page for explanations of acronyms and abbreviations used in this report. All chirp systems use an acoustic signal of continuously varying frequency; the EdgeTech 512i system used during this survey produced high-resolution, shallow-penetration (typically less than 50 milliseconds [ ms] ) profile images of sub-seafloor stratigraphy. The towfish contains a transducer that transmits and receives acoustic energy and typically is towed 1–2 meters ( m ) below the sea surface. As transmitted acoustic energy intersects density boundaries, such as the seafloor or sub-surface sediment layers, some energy is reflected back toward the transducer, received, and recorded by a Personal Computer ( PC) -based seismic acquisition system. This process is repeated at regular intervals (for example, 0.125 seconds ( s) ) and returned energy is recorded for a specific duration (for example, 50 ms ). In this way, a two-dimensional ( 2-D ) vertical image of the shallow geologic structure beneath the ship's track is produced. Figure 2 displays the acquisition geometry. Refer to table 1 for a summary of acquisition parameters and table 2 for trackline statistics. The archived trace data are in standard SEG Y rev. 0 format (Barry and others, 1975); the first 3,200 bytes of the card image header are in American Standard Code for Information Interchange ( ASCII ) format instead of Extended Binary Coded Decimal Interchange Code ( EBCDIC ) format. The SEG Y files are available on the DVD version of this report or online, downloadable via the USGS Coastal and Marine Geoscience Data System ( http://cmgds.marine.usgs.gov ). The data are also available for viewing using GeoMapApp ( http://www.geomapapp.org ) and Virtual Ocean ( http://www.virtualocean.org ) multi-platform open source software. The Web version of this archive does not contain the SEG Y trace files. To obtain the complete DVD archive, contact USGS Information Services at 1-888-ASK-USGS or infoservices@usgs.gov. The SEG Y files may be downloaded and processed with commercial or public domain software such as Seismic Unix ( SU ) (Cohen and Stockwell, 2010). See the How To Download SEG Y Data page for download instructions. The printable profiles are provided as Graphics Interchange Format ( GIF ) images processed and gained using SU software and can be viewed from the Profiles page or by using the links located on the trackline maps; refer to the Software page for links to example SU processing scripts.

Louisana↗

USGS2016

Archive of ground penetrating radar data collected during USGS field activity 13BIM01—Dauphin Island, Alabama, April 2013

From April 13 to 20, 2013, scientists from the U.S. Geological Survey St. Petersburg Coastal and Marine Science Center (USGS-SPCMSC) conducted geophysical and sediment sampling surveys on Dauphin Island, Alabama, as part of Field Activity 13BIM01 . The objectives of the study were to quantify inorganic and organic accretion rates in back-barrier and mainland marsh and estuarine environments. Various field and laboratory methods were used to achieve these objectives, including subsurface imaging using Ground Penetrating Radar (GPR), sediment sampling, lithologic and microfossil analyses, and geochronology techniques to produce barrier island stratigraphic cross sections to help interpret the recent (last 2000 years) geologic evolution of the island. This data series report is an archive of GPR and associated Global Positioning System (GPS) data collected in April 2013 from Dauphin Island and adjacent barrier-island environments. In addition to GPR data, marsh core and vibracore data were also collected collected but are not reported (or included) in the current report. Data products, including elevation-corrected subsurface profile images of the processed GPR data, unprocessed digital GPR trace data, post-processed GPS data, Geographic Information System (GIS) files and accompanying Federal Geographic Data Committee (FGDC) metadata, can be downloaded from the Data Downloads page.

Alabama↗

USGS2016

Application of ground penetrating radar for identification of washover deposits and other stratigraphic features: Assateague Island, MD

A combination of ground penetrating radar (GPR) data, core data, and aerial photographs were analyzed to better understand the evolution of two portions of Assateague Island, Maryland. The focus of the study was to investigate the applicability of using GPR data to image washover deposits in the stratigraphic record. High amplitude reflections observed in two shore-perpendicular GPR profiles were correlated to shallow (<1 m) lithologic contacts observed in sediment cores. At these contacts, deposits consisting primarily of quartz sand overlie sediments with organic matter that include degraded plant root or stem material. The underlying organic matter likely represents the vegetated portion of the barrier island that was buried by washover fans deposited during hurricanes Irene (2011) and Sandy (2012), as indicated in high-resolution aerial photographs. The GPR data were able to delineate the washover deposits from the underlying stratigraphic unit; however, the radar data did not resolve finer structures necessary to definitively differentiate washover facies from other sand-rich deposits ( e.g., flood-tide deltas and dunes). Other GPR profiles contain reflections that likely correlate to geomorphic features like tidal channels and vegetated zones observed in historical aerial imagery. Burial of these features by overwash fluxes were observed in the aerial imagery and thus the resulting radar sequence is largely interpreted as washover deposits. Deeper, channel-like features that have been infilled were also observed in shore-parallel profiles and these features coincide with scour channels observed in the 1966 aerial photography. Additional sedimentological data are required to determine what role overwash played in the in-filling of these features.

Journal of Environmental & Engineering Geophysics↗

USGS2015

Archive of digital chirp subbottom profile data collected during USGS Cruise 13CCT04 offshore of Petit Bois Island, Mississippi, August 2013

From August 13-23, 2013, the U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers (USACE) conducted geophysical surveys to investigate the geologic controls on barrier island framework and long-term sediment transport offshore of Petit Bois Island, Mississippi. This investigation is part of a broader USGS study on Coastal Change and Transport (CCT). These surveys were funded through the Mississippi Coastal Improvements Program (MsCIP) with partial funding provided by the Northern Gulf of Mexico Ecosystem Change and Hazard Susceptibility Project. This report serves as an archive of unprocessed digital chirp subbottom data, trackline maps, navigation files, Geographic Information System (GIS) files, Field Activity Collection System (FACS) logs, and formal Federal Geographic Data Committee (FGDC) metadata. Gained-showing a relative increase in signal amplitude-digital images of the seismic profiles are provided.

Mississippi↗