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Site content related to keyword: "Sussex County"

RI63 An Evaluation of Sand Resources, Atlantic Offshore, Delaware

RI63 An Evaluation of Sand Resources, Atlantic Offshore, Delaware

Lithologic logs from 268 vibracores taken from the Delaware Atlantic offshore were evaluated for sediment type and compatibility with historical beach sediment textures. A model of sand resource evaluation, known as "stack-unit mapping" (Kempton, 1981) was applied to all of the cores, and each core was labeled by its lithology in vertical sequence. The results are shown in detailed maps of the beach-quality sand resources offshore in state and federal waters. Results show significant quantities (approximately 54 million cubic yards) of excellent beach-quality sand sources within the three-mile state limit offshore Indian River Inlet, and within the Inner Platform and Detached Shoal Field geomorphic regions. In federal waters, sand is found on Fenwick Shoal Field and farther offshore Indian River Inlet on the Outer Platform (approximately 43.6 million cubic yards combined). Most of the beach-quality sand resources are believed to be reworked tidal delta deposits of a former Indian River Inlet during periods of lower sea level. Farther south, the resources are accumulations of recent surficial sands of the inner shelf (Detached Shoal Field and Fenwick Shoal Field) showing that the geomorphic region does influence sediment quality. This study found that paleochannels and bathymetry had no relationship to grain size. Multiple cut and fill episodes contributed to the diversity in grain sizes.

RI62 The Cypress Swamp Formation, Delaware

RI62 The Cypress Swamp Formation, Delaware

The Cypress Swamp of Sussex County, Delaware, is underlain by a body of late Pleistocene- to Holocene-age unconsolidated sediments. They form a mappable geologic unit herein named the Cypress Swamp Formation. Deposits of the formation can be found outside the current boundaries of the Cypress Swamp and record the erosion and redistribution of older Pleistocene coastal and Pliocene sedimentary units.

RI55 Geology of the Milford and Mispillion River Quadrangles

RI55 Geology of the Milford and Mispillion River Quadrangles

Investigation of the Neogene and Quaternary geology of the Milford and Mispillion River quadrangles has identified six formations: the Calvert, Choptank, and St. Marys formations of the Chesapeake Group, the Columbia Formation, and the Lynch Heights and Scotts Comers formations of the Delaware Bay Group. Stream, swamp, marsh, shoreline, and estuarine and bay deposits of Holocene age are also recognized. The Calvert, Choptank, and St. Marys formations were deposited in inner shelf marine environments during the early to late Miocene. The Columbia Formation is of fluvial origin and was deposited during the middle Pleistocene prior to the erosion and deposition associated with the formation of the Lynch Heights Formation. The Lynch Heights Formation is of fluvial and estuarine origin and is of middle Pleistocene age. The Scotts Corners Formation was deposited in tidal, nearshore, and estuarine environments and is of late Pleistocene age. The Scotts Corners Formation and the Lynch Heights Formation are each interpreted to have been deposited during more than one cycle of sea-level rise and fall. Latest Pleistocene and Holocene deposition has occurred over the last 11,000 years.

RI53 Geology of the Seaford Area, Delaware

RI53 Geology of the Seaford Area, Delaware

This report supplements the map "Geology of the Seaford Area, Delaware" (Andres and Ramsey, 1995). The map portrays surficial and shallow subsurface stratigraphy and geology in and around the Seaford East and Delaware portion of the Seaford West quadrangles. The Quaternary Nanticoke deposits and Pliocene Beaverdam Formation are the primary lithostratigraphic units covering upland surfaces in the map area. Recent swamp, alluvial, and marsh deposits cover most of the floodplains of modern streams and creeks. The Miocene Choptank, St. Marys, and Manokin formations occur in the shallow subsurface within 300 ft of land surface. The Choptank, St. Marys, and Manokin formations were deposited in progressively shallower water marine environments. The Beaverdam Formation records incision of underlying units and progradation of a fluvial-deltaic system into the map area. The geologic history of the Quaternary is marked by weathering and erosion of the surface of the Beaverdam and deposition of the Nanticoke deposits by the ancestral Nanticoke River. Depositional environments in the Nanticoke deposits include fresh water streams and ponds, estuarine streams and lagoons, and subaerial dunes.

RI49 Results of the Coastal Sussex County, Delaware Ground-Water Quality Survey

RI49 Results of the Coastal Sussex County, Delaware Ground-Water Quality Survey

The results of this investigation of the Columbia aquifer in coastal Sussex County, Delaware, provide some of the data necessary to evaluate the condition of the area's primary source of fresh water. Chemical analyses of water samples from domestic, agricultural, public, and monitoring wells document the effects of past and present land use practices. Groundwater flow paths and flow systems are inferred from flow-net analysis, ground-water chemistry, and isotopic composition.

RI47 Ages of the Bethany, Beaverdam, and Omar Formations of Southern Delaware

RI47 Ages of the Bethany, Beaverdam, and Omar Formations of Southern Delaware

The microflora of the Bethany formation and the lower part of the Beaverdam Formation is characterized by a Quercus-Carya assemblage, very few non-arboreal pollen, and Pterocarya and Sciadopitys as exotic constituents. This assemblage has much in common with that of the Brandywine Formation of Maryland and the Eastover Formation of Virginia which are of late Miocene or early Pliocene age. The environment of deposition of the Bethany was probably deltaic, and that of the lower Beaverdam fluviatile.

RI46 Shallow Subsurface Temperatures at Selected Locations in Delaware

RI46 Shallow Subsurface Temperatures at Selected Locations in Delaware

Subsurface temperatures were measured in instrumented boreholes for about one and one-half years at depths down to 10 feet below land surface at four locations in the State. In New Castle County, temperatures were measured periodically in the field about twice a month at three sites, and, in Sussex County, they were automatically recorded every 15 minutes at one site. The depths of interest are generally in the unsaturated zone and are subject to both daily temperature fluctuations and longer seasonal changes.

RI45 Effects of Agricultural Practices and Septic-System Effluent on the Quality of Water in the Unconfined Aquifer in Parts of Eastern Sussex County, Delaware

RI45 Effects of Agricultural Practices and Septic-System Effluent on the Quality of Water in the Unconfined Aquifer in Parts of Eastern Sussex County, Delaware

The unconfined aquifer is a major source of water supply in eastern Sussex County, Delaware. It also is an important source of water for surface-water bodies and deeper, confined aquifers. The aquifer consists mainly of permeable sand and gravel; its shallow water table is susceptible to contamination by nitrate and other chemical constituents associated with agricultural practices and effluent from septic systems.

RI42 Stratigraphy and Depositional History of the Post-Choptank Chesapeake Group

RI42 Stratigraphy and Depositional History of the Post-Choptank Chesapeake Group

Onshore and offshore geological and geophysical data were used to investigate the lithostratigraphy, seismic stratigraphy, and depositional history of the late Tertiary age post-Choptank Chesapeake Group rocks in Sussex County, Delaware and adjacent counties in Maryland. The results of this investigation suggest that the St. Marys (?) Formation and the sandy interval of which the Manokin aquifer is a part, are distinct lithostratigraphic units. The Manokin formation is proposed as an informal lithostratigraphic unit that refers to the sandy interval of which the Manokin aquifer is a part. On a regional scale, the section containing the Ocean City and Pocomoke aquifers and adjacent and intervening confining beds is best treated as a single undifferentiated lithostratigraphic unit. The Bethany formation is proposed as an informal lithostratigraphic unit that refers to this section.

RI41 Hydrogeology and Geochemistry of the Unconfined Aquifer, West-Central and Southwestern Delaware

RI41 Hydrogeology and Geochemistry of the Unconfined Aquifer, West-Central and Southwestern Delaware

The unconfined aquifer is the major source of water supply in west-central and southwestern Delaware. The aquifer, which is composed of quartz sand, gravel, clay, and silt, ranges in thickness from 20 to 200 feet. The water table ranges from land surface to about 20 feet below land surface. Analyses of water from wells distributed throughout the area were used to study processes controlling the chemical quality of the water in the unconfined aquifer.

SP14 Basic Hydrologic Data for Coastal Sussex County, Delaware

SP14 Basic Hydrologic Data for Coastal Sussex County, Delaware

There is no abstract on file for this publication.

Groundwater Resources of Sussex County (with an update for Kent County)

Project Contact(s):

This project is an integrated geologic/hydrologic study that will update our knowledge of the unconfined aquifers, confined aquifers, and groundwater resources of Sussex County. In addition, this project will utilize the results of recently completed study of the aquifer geology of Kent County (McLaughlin and Velez, 2005) to better define the groundwater resources of Kent County. The products to be produced by this study include aquifer depth and thickness maps and geologic cross sections for Sussex County. Products will also include a summary of basic hydrologic characteristics of aquifers in Kent and Sussex County and an analysis of water use for each aquifer.

OFR20 Configuration of the Base and Thickness of the Unconfined Aquifer in Southeastern Sussex County, Delaware

OFR20 Configuration of the Base and Thickness of the Unconfined Aquifer in Southeastern Sussex County, Delaware

The purpose of this study was to map the thickness and the configuration of the base of the unconfined aquifer in southeastern Sussex County, Delaware (figure 1). The unconfined aquifer provides much of the water used in this part of the State and is the first unit to be affected by pollution or waste disposal problems. Contour maps and geologic sections were prepared from available geologic, geophysical, and drillers' logs and previously published reports and maps. Six test holes (figure 1) were drilled to supplement available data. The information in this report will be useful for water-resources planning and for locating water-supply wells in the unconfined aquifer.

OFR7 Review of the Subsurface Geology and Resource Potential of Southern Delaware

OFR7 Review of the Subsurface Geology and Resource Potential of Southern Delaware

This review summarizes the present knowledge of the subsurface geology and resource potential of southern Delaware and outlines the needs for future studies to gain further understanding of these matters. Because of the present interest in exploring for oil and gas beneath the Atlantic Outer Continental Shelf it is most timely that the primary resource considered in this report be the hydrocarbon (petroleum and natural gas) potential of the State. Hydrocarbons occur in commercial quantities only in thick sections of sedimentary rock, therefore, southern Delaware (primarily Sussex County) is the focus of this study because the thickest sedimentary rock section in the State is here. Assessment of the hydrocarbon potential of this area also has bearing on other resources such as groundwater (both fresh water and subsurface brines), underground storage of natural gas, and underground waste disposal.

OFR48 Results of the Domestic Well Water-Quality Study

OFR48 Results of the Domestic Well Water-Quality Study

The Delaware Geological Survey conducted a review of existing ground-water quality data collected from shallow (less than 100 feet deep) domestic water-supply wells and small public water-supply wells (serving fewer than 100 residents) to determine the extent to which toxic and carcinogenic compounds are present in the shallow ground water serving domestic water supply wells. These data were generated by several agencies including the Delaware Geological Survey, U.S. Geological Survey, Delaware Department of Natural Resources and Environmental Control, Delaware Division of Public Health Office of Drinking Water, and the Delaware Department of Agriculture Pesticide Management Program.

Number of Pages: 
55

OFR41 Beach Sand Textures from the Atlantic Coast of Delaware

OFR41 Beach Sand Textures from the Atlantic Coast of Delaware

The purpose of this report is to characterize Delaware Atlantic Coast beach sand on the basis of sand texture data in order to identify geologic material suitable for beach nourishment.

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RI38 Hydrology of the Manokin, Ocean City, and Pocomoke Aquifers of Southeastern Delaware

RI38 Hydrology of the Manokin, Ocean City, and Pocomoke Aquifers of Southeastern Delaware

Population and accompanying water use are expected to increase by 34 percent in southeastern Delaware between 1975 and 2000. To assess the capability of the aquifers in that area to supply the required amount of ground water, a study of those aquifers was started in 1976. Interpretation of geologic sections developed from drilling and geophysical data showed that the confining beds between the Manokin, Ocean City, and Pocomoke aquifers of Neogene age are thin and discontinuous in some parts of the area. Possible fault zones coinciding with deep tectonic features may also contribute to interconnection of these aquifers. Hydrographs of water levels in the aquifers show differential drawdown during periods of heavy pumping, but levels return to a common altitude during unstressed periods. Because of these characteristics, the Manokin, Ocean City, and Pocomoke aquifers are considered to be a single confined aquifer, in most places.

RI36 History of Oil and Gas Exploration in the Mid-Atlantic Region and Delaware's Involvement in the Federal OCS Leasing Program

RI36 History of Oil and Gas Exploration in the Mid-Atlantic Region and Delaware's Involvement in the Federal OCS Leasing Program

There has been sporadic exploration for oil and gas in the Mid-Atlantic region for over 50 years. Non-commercial deposits of oil and gas have recently been discovered in the sedimentary rock section of the Outer Continental Shelf (OCS) 80 miles off the New Jersey-Delaware coast. The oil and gas occurs within entrapment structures in ancient rocks deposited and buried in a deep basin called the Baltimore Canyon trough. This trough forms part of the Coastal Plain and continental shelf geologic provinces on the Atlantic Coast.

OFR36 Summary Report: The Storm of January 4, 1992

OFR36 Summary Report: The Storm of January 4, 1992

On January 4, 1992 an intense storm moved from the east across the Delmarva Peninsula and the Chesapeake Bay. Its track was the result of the low pressure being pulled westward by a strong cold-cored upper low moving across Georgia and South Carolina. The storm exhibited tropical/subtropical characteristics on radar. Satellite photos indicate that an "eye" to the storm formed just prior to landfall. Landfall occurred over the southern Delmarva Peninsula just prior to the time of high tide (0648 at Ocean City, Md). The storm weakened rapidly as it moved over land areas with a secondary area redeveloping farther out to sea later in the day on the 4th. Approximate locations of the storm's track are given on Figure 1. As the storm moved across the Delmarva Peninsula perpendicular to the coast, Delaware was in the right-foreward quadrant to the north of the "eye" of the storm. This position typically produces the highest winds associated with a tropical storm. These winds created high waves that in conjunction with an astronomical high tide (new moon) produced strong surf and abnormally high tides along the shore. Rainfall from the storm in Delaware was not heavy enough to cause flooding of streams. Coastal flooding of marshes and low-lying areas did occur along the Inland Bays and along Delaware Bay.

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OFR33 Ground-Water Level and Chemistry Data from the Coastal Sussex County, Delaware, Ground-Water Quality Survey

OFR33 Ground-Water Level and Chemistry Data from the Coastal Sussex County, Delaware, Ground-Water Quality Survey

This report contains the supporting ground-water level and chemistry data and the data collection methodology for Delaware Geological Survey Report of Investigations No. 49, "Results of the Coastal Sussex County, Delaware, Ground-Water Quality Survey" (Andres, 1991). Because raw data are commonly requested, they are published here in open-file format to accommodate those needing it for further analysis.

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