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Browsing by Author "Ramsey, K.W."

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Ages Of The Bethany, Beaverdam, And Omar Formations Of Southern Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 1990-02) Groot, J.J.; Ramsey, K.W.; Wehmiller, John F.
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.
Basic Data For The Geologic Map Of The Seaford Area, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 1995) Andres, A.S.; Ramsey, K.W.; Schenck, W.S.
The Seaford area geologic mapping project (Andres and Ramsey, 1995) was conducted by Delaware Geological Survey (DGS) staff and focused on the Seaford East (SEE) and Delaware portion of the Seaford West (SEW) quadrangles (Fig. 1). Data evaluated in support of mapping from these quadrangles and surrounding areas are documented in this report.
Beach Sand Textures From The Atlantic Coast Of Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 1999) Ramsey, K.W.
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.
Cross Section Of Pliocene And Quaternary Deposits Along The Atlantic Coast Of Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 1999) Ramsey, K.W.
Exploration for sand resources for beach nourishment has led to an increase in the amount of geologic data available from areas offshore Delaware's Atlantic Coast. These data are in the form of cores, core logs, and seismic reflection profiles. In order to provide a geologic context for these offshore data, this cross section has been constructed from well and borehole data along Delaware's Atlantic coastline from Cape Henlopen to Fenwick Island. Placing the offshore data in geologic context is important for developing stratigraphic and geographic models for predicting the location of stratigraphic units found offshore that may yield sand suitable for beach nourishment. The units recognized onshore likely extend offshore to where they are truncated by younger units or by the present seafloor.
An Evaluation Of Sand Resources, Atlantic Offshore, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2002) McKenna, K.K.; Ramsey, K.W.
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.
Geologic And Hydrologic Studies Of The Oligocene - Pleistocene Section Near Lewes, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 1990-10) Andres, A.S.; Benson, R.N.; Ramsey, K.W.; Talley, J.H.
Borehole Oh25-02, located about 3 miles southwest of Lewes, Delaware, ends at a total depth of 1,337 ft in a mid-Oligocene glauconitic silt unit. It penetrated 317 ft of glauconitic sands and silts between the base of the Calvert Formation at a depth of 1,020 ft and total depth. A hiatus at 1,218 ft separates an outer neritic lower Miocene interval (Globorotalia kugleri Zone) above it from a deep upper bathyal mid-Oligocene (G. opima opima Zone) section below; the lower section is characterized by abundant large uvigerinid benthic foraminiferal species representing the transition from Uvigerina tumeyensis to Tiptonina nodifera. Similar uvigerinid assemblages identify the mid-Oligocene unit in boreholes near Bridgeville and Milford, Delaware; Cape May, New Jersey; and Ocean City, Maryland. Updip from these boreholes, the Calvert Formation, of latest Oligocene-middle Miocene age in Delaware, unconformably overlies middle Eocene glauconitic sands of the Piney Point Formation. The juxtaposition of the downdip mid-Oligocene rocks against the updip middle Eocene rocks can best be explained by a fault between the two regions.
Geologic Map of Kent County, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2007) Ramsey, K.W.
Geologic Map Of New Castle County, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2005) Ramsey, K.W.
Geologic Map of Offshore Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2020-02) Mattheus, C.R.; Ramsey, K.W.; Tomlinson, J.L.
Delineation of map units is based on sediment-core descriptions (e.g., texture, color, and composition) from 469 locations and seafloor morphology, which was assessed from a seamless NOAA/USGS topo-bathymetric model (Pendleton et al., 2014). The latter was integrated with high-resolution ‘chirper’ seismic reflection data, collected in 2013 by the Delaware Division of Natural Resources and Environmental Conservation (DNREC) and in 2015 as part of the 2015-2017 Bureau of Ocean Energy Management (BOEM) Atlantic Sand Assessment Project (ASAP), using sweep frequency pulses of 2-12 kHz and 0.7-12 kHz, respectively. Stratigraphic mapping based on these data allowed seafloor composition to be inferred across areas of limited core coverage (e.g., Federal waters, beyond 3 miles from shore) and facilitated the delineation of unit boundaries based on subsurface trends and seafloor geomorphology. A minimum surface-unit thickness of 1 ft served as the cut-off for geologic mapping of the seafloor, given the vertical resolution constraints of geophysical data. If surficial sediments were <1 ft thick, the underlying unit was mapped. Unit names and descriptions conform to those established in prior subsurface work along the Delaware barrier shoreline by Ramsey (1999), a synthesis of the Delaware coastal plain geology (Ramsey, 2010), and a previous map which included portions of the offshore surface geology (Ramsey and Tomlinson, 2012).
Geologic Map Of Southern Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 1990-06) Ramsey, K.W.; Schenck, W.S.
This geologic map shows: (1) distribution of geologic units found at the land surface; (2) updip limit (generally the northern extent) of Miocene and Pliocene geologic units found in the subsurface; and (3) locations of major subsurface faults that affected deposition of the Miocene and Pliocene geologic units. The geologic units shown are defined on their dominant lithologies (i.e., sand, silt, clay) and other characteristics such as presence or absence of shells or other fossils and range of colors.
Geologic Map of the Bethany Beach and Assawoman Bay Quadrangles, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2012-12) Ramsey, K.W.; Tomlinson, J.L.
The geologic history of the surficial units of the Bethany Beach and Assawoman Bay Quadrangles is that of deposition of the Beaverdam Formation and its subsequent modification by erosion and deposition related to sea-level fluctuations during the Pleistocene. The geology reflects this complex history onshore, in Indian River Bay and Assawoman Bay, and offshore in the Atlantic Ocean. Erosion during the late Pleistocene sea-level lowstand and ongoing deposition offshore and in Indian River Bay during the Holocene rise in sea level represents the latest of several cycles of erosion and deposition.
Geologic Map of the Cecilton and Middletown Quadrangles, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2020-09) Tomlinson, J.L.; Ramsey, K.W.
Mapping was conducted using field maps at a scale of 1:12,000 with 2-ft contours. Stratigraphic boundaries drawn at topographic breaks reflect detailed mapping using contours not shown on this map. Most stratigraphic units mapped in stream valleys are projected from subsurface data. Except for a few erosional bluffs, these units are covered by colluvium. This map supersedes Geology of the Middletown-Odessa Area, Delaware: Delaware Geological Survey Geologic Map Series No. 2 (Pickett and Spoljaric, 1971). The geology of the map area reflects a complex history with a cut and fill geometry where the Pleistocene-aged deposits incised into older units. The Tertiary deposits were modified by erosion and deposition of the Columbia Formation during the early Pleistocene and again by the Lynch Heights and Scotts Corners Formations as a result of sea-level fluctuations during the middle to late Pleistocene. The geology is further complicated by periglacial activity that produced Carolina Bay deposits in the map area, which modified the land surface.
Geologic Map of the Elkton, Saint Georges, and Delaware City Quadrangles, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2023-05) Tomlinson, J.L.; Ramsey, K.W.
Geologic mapping was conducted at 1:12,000 with a 1-ft contour basemap. In some instances, stratigraphic boundaries drawn at topographic breaks reflect detailed mapping using LiDAR data. Elevations of stratigraphic contacts along stream valleys are projected from subsurface data. Except for a few erosional bluffs, these contacts are covered by colluvium. This map supersedes this portion of Geology of the Chesapeake and Delaware Canal Area, Delaware: Delaware Geological Survey Geologic Map Series No. 1 (Pickett, 1970) and Geologic Map of New Castle County, Delaware: Delaware Geological Survey Geologic Map Series No. 13 (Ramsey, 2005). The geological history of the surficial units of the Elkton, Saint Georges, and Delaware City Quadrangles is the result of erosion of the Potomac Formation and younger Cretaceous and Cenozoic units by glacial dam burst events during the early Pleistocene. These periods of erosion were followed by stream incision and fluvial and estuarine deposition associated with multiple sea-level fluctuations during the middle to late Pleistocene. Periglacial activity that followed produced Carolina Bay deposits, alluvium along stream valley slopes, and freeze-thaw features on the land surface.
Geologic Map Of The Ellendale And Milton Quadrangles, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2001) Ramsey, K.W.
Geologic Map of the Fairmount and Rehoboth Beach Quadrangles, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2011) Ramsey, K.W.
The map shows and describes the geologic units found at the land surface and in the shallow subsurface in the map area. The purpose of the map is to provide geologic information that can be used for determining such things as the geology of watersheds, recognition of the relationship between geology and regional environmental or land-use issues to support land-use and regulatory decision making, and identification of potential locations of sand and gravel resources.
Geologic Map of the Frankford and Selbyville Quadrangles, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2013-12) Tomlinson, J.L.; Ramsey, K.W.; Andres, A.S.
The geological history of the surficial units of the Frankford and Delaware portion of the Selbyville Quadrangles was the result of deposition of the Beaverdam Formation during the late Pliocene and its subsequent modification by erosion and deposition related to sea-level fluctuations during the Pleistocene. The geology at the land surface was then further modified by periglacial activity that produced dune deposits in the map area. Surficial geologic mapping was conducted using field maps at a scale of 1:12,000 with 2 foot contours. Stratigraphic boundaries drawn at topographic breaks reflect detailed mapping using contours not shown on this map.
Geologic Map of the Frederica and Bennetts Pier Quadrangles, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2024) Tomlinson, J.L.; Ramsey, K.W.
Geologic mapping was conducted at 1:12,000 with a 1-ft contour basemap. In some instances, stratigraphic boundaries drawn at topographic breaks and highs reflect detailed mapping using LiDAR data. Elevations of stratigraphic contacts along stream valleys are projected from subsurface data. Except for a few erosional bluffs, these contacts are covered by colluvium. Carolina Bay deposits were visually identified using a hillshade digital elevation model (DEM). This map supersedes Geology of the South-Central Kent County Area, Delaware: Delaware Geological Survey Geologic Map Series No. 7 (Pickett and Benson, 1986) and Geologic Map of Kent County, Delaware: Delaware Geological Survey Geologic Map Series No. 14 (Ramsey, 2007). The geological history of the surficial units of the Frederica and Bennetts Pier Quadrangles is the result of erosion of the Choptank and Beaverdam Formations by glacial dam burst events during the early Pleistocene. These periods of erosion were followed by fluvial and estuarine deposition associated with multiple sea-level fluctuations during the middle to late Pleistocene. Periglacial activity that followed produced Carolina Bay deposits and freeze-thaw features on the land surface. Marsh sediments deposited during the Holocene further modified the geology.
Geologic Map Of The Georgetown Quadrangle, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2010) Ramsey, K.W.
The geologic history of the surficial geologic units of the Georgetown Quadrangle is primarily that of deposition of the Beaverdam Formation and its subsequent modification by erosion and deposition of younger stratigraphic units. The age of the Beaverdam Formation is uncertain due to the lack of age-definitive fossils within the unit. Stratigraphic relationships in Delaware indicate that it is no older than late Miocene and no younger than early Pleistocene. Regional correlations based on similarities of depositional style, stratigraphic position, and sediment textures suggest that it is likely late Pliocene in age; correlative with the Bacons Castle Formation of Virginia (Ramsey, 1992, 2010).
Geologic Map of the Harbeson Quadrangle, Delaware
(Newark, DE: Delaware Geological Survey, University of Delaware, 2011) Ramsey, K.W.; Tomlinson, J.L.
The complex geologic history of the surficial units of the Harbeson Quadrangle is one of deposition of the Beaverdam Formation and its subsequent modification by erosion and deposition related to sea-level fluctuations during the Pleistocene. The geology is further complicated by periglacial activity that produced dune deposits and Carolina Bays scattered throughout the map area.
Geologic map of the Lewes and Cape Henlopen quadrangles, Delaware
(Newark, DE : Delaware Geological Survey, University of Delaware, 2003) Ramsey, K.W.