Northern Atlantic Coastal Plain Research Articles

Late Quaternary eolian dune-field mobilization and stabilization near the Laurentide Ice Sheet limit, New Jersey Pine Barrens, eastern USA

Well-preserved stabilized dune fields are widespread in the New Jersey Pine Barrens, northern Atlantic Coastal Plain, USA. In this area, which was unglaciated throughout the Quaternary, quartz-rich Miocene–Pleistocene age fluvial and marginal marine sands provided source sediments for eolian mobilization. Parabolic and transverse dunes within fluvial source-bordering dune fields in small-river watersheds migrated to the east-southeast (110–125°) over unconsolidated sands and gravels. The short eolian transport distance of most dune-field sand in the presence of moderately to sub-rounded quartz grains with low sphericity indicates eolian abrasion and dune-sand fashioning occurred within a short duration of transport. Although the absolute duration of eolian transport remains unknown, dune stabilization occurred about 23–17.5 ka, with a weighted mean of 19.5 ± 0.5 ka from six dated dunes. Dune stabilization coincided with northward retreat of the Laurentide Ice Sheet from its maximum position at ∼41.500° N (∼100 km north of the study area), to ∼41.375°N (∼200 km north). The well-preserved dune morphology and narrowly constrained ages suggest rapid dune stabilization. Dune-forming katabatic winds from the WNW declined abruptly with northward migration of the ice sheet, accompanied by climatic amelioration and stabilization by vegetation. A short-lived period of eolian mobilization may have been associated with a temporary increase in sand availability from adjacent fluvially derived sediments. Post-depositional processes included soil eluviation, with dissolution features and breakage blocks on quartz grains signifying long-term in-situ soil weathering.

Manganese in the Northern Atlantic Coastal Plain aquifer system, eastern USA—Modeling regional occurrence with pH, redox, and machine learning

Study regionThe study was conducted in the Northern Atlantic Coastal Plain aquifer system, eastern USA, an important water supply in a densely populated region. Study focusManganese (Mn), an emerging health concern and common nuisance contaminant in drinking water, is mapped and modeled using the XGBoost machine learning method, predictions of pH and redox conditions from previous models, and other explanatory variables that describe the groundwater flow system and surface characteristics. Methods to address the imbalanced occurrence of elevated and low Mn concentrations are compared and used to more accurately predict concentrations of interest for human health and drinking water quality. New hydrological insights for the regionElevated Mn concentrations were more likely in shallow groundwater, close to recharge areas and in topographically low areas where soil or unsaturated processes influence groundwater quality. Predicted concentrations greater than the health threshold of 300 micrograms per liter extended across 17 % of the surficial aquifer area, but across <1% of the areas of underlying aquifers. pH and variables related to flow-system position and near-surface processes were more important predictors than the probability of low dissolved oxygen (DO). Mapped variable influence (SHAP values) showed that both pH and DO variables were related to hydrogeologic conditions. Class weights, which improved the predictive ability for elevated Mn without altering the data, was the preferred method to address class imbalance.

Machine-learning models to map pH and redox conditions in groundwater in a layered aquifer system, Northern Atlantic Coastal Plain, eastern USA

Study regionThe study was conducted in the Northern Atlantic Coastal Plain aquifer system, in the eastern USA. Study focusGroundwater pH and redox conditions are fundamental chemical characteristics controlling the distribution of many contaminants of concern for drinking water or the ecological health of receiving waters. In this study, pH and redox conditions were modeled and mapped in a complex, layered aquifer system. Machine-learning methods (boosted regression trees) were applied to data from 3000 to 5000 wells. Predicted pH and the probability of anoxic conditions, defined by three thresholds of dissolved oxygen (0.5, 1, and 2 mg/L), were mapped at the 1-km2 scale for each of 10 regional aquifer layers. New Hydrological Insights for the RegionMaps depict the extent of acidic groundwater and oxic conditions in the shallow, unconfined surficial aquifer and in unconfined, recharge-proximal areas of underlying aquifers, in contrast to alkaline and anoxic groundwater elsewhere. Geographic patterns and influential predictors–including elevation, overlying confining-units thickness, and simulated groundwater age and flux–are consistent with prior understanding of the processes controlling pH and redox in the aquifer system. The model-based maps support robust estimates of aquifer proportions, either areal or volumetric, likely to contain groundwater of a specified quality or be vulnerable to specific pH- or redox-sensitive contaminants. The machine-learning methods were an effective tool to map groundwater quality at the regional scale.

Drought assessment with a surface-groundwater coupled model in the Chesapeake Bay watershed

An integrated framework of surface and groundwater models is essential for the comprehensive understanding of impacts of droughts due to surface water and subsurface exchanges. We evaluate the response of soil moisture and groundwater dynamics during drought in the Northern Atlantic Coastal Plain in the Chesapeake Bay Watershed. The Variable Infiltration Capacity model coupled with MODFLOW (VICMF) was implemented and several variables were used in the Multivariate Standardized Drought Index (MSDI) that consider multivariate perspectives of droughts. Three drought indices were derived (MSDI_PSV, MSDI_PSM, MSDI_PWM) (PSV: Precipitation and Soil moisture from VIC; PSM: Precipitation and Soil moisture from VICMF, PWM: Precipitation and WTE from VICMF), and the accuracy of the results was verified using a performance measure (Drought area Agreement (%); DA) and a statistical test to evaluate spatial extent of the drought areas. The MSDI_PWM showed better results for predicting drought events as it captured overall drought conditions.

Effects of tillage practices on drainage and nitrate leaching from winter wheat in the Northern Atlantic Coastal-Plain USA

Management strategies for winter wheat (Triticum aestivum L., cultivar Pioneer “2548”) in the Northern Atlantic Coastal-Plain region of the USA must balance agronomic production with practices to reduce nitrate-N (NO3-N) leaching, because much of this region lies within the Chesapeake Bay watershed. Winter wheat in this region is commonly grown using no-tillage (NT), but few studies have evaluated the effects of NT on NO3-N leaching for winter wheat. A four-year lysimeter study was conducted in Beltsville, Maryland by growing winter wheat in eight tension-drained undisturbed soil-column lysimeters (41cm diameter by 100cm deep) configured to exclude runoff, to compare the effects of NT vs. simulated plow-tillage (PT) and N fertilization practices on drainage volumes and NO3-N leaching. Additional data documented wheat total N uptake and bromide leaching. The temporal pattern of drainage showed that NT produced significant, but modestly higher, drainage volumes than PT during fall establishment (mid-Oct. to mid-Dec.), which increased the potential for NO3-N leaching, especially following high rainfalls. However, the greater risk of NO3-N leaching with NT during establishment decreased in the spring as tillage effects subsided and wheat water-use and N uptake became dominant. The increased fall leaching risk with NT can be managed by reducing fall-N applications, but both NT and PT can benefit from reduced NO3-N leaching resulting from spring split-N applications. The final NO3-N leaching losses depend on the interactions of precipitation timing and amount, fertilizer-N rate and timing, and initial soil water status. Additional winter-wheat NO3-N leaching research is needed to study to a wider range of soils, to assess high-residue vertical-tillage implements, and to evaluate precision application of spring fertilizer-N.

Estimating Contributions of Nitrate and Herbicides From Groundwater to Headwater Streams, Northern Atlantic Coastal Plain, United States 1

Abstract:  Groundwater transport often complicates understanding of surface-water contamination. We estimated the regional flux of nitrate and selected herbicides from groundwater to nontidal headwater streams of the Atlantic Coastal Plain (New Jersey through North Carolina) based on late-winter or spring base-flow samples from 174 streams. Sampled streams were selected randomly, and flux estimates are based on resulting population estimates rather than on empirical models, which have been used previously for similar estimates. Base-flow flux in the estimated 8,834 headwater streams of the study area are an estimated 21,200 kg/day of nitrate (as N) and 5.83, 0.565, and 20.7 kg/day of alachlor, atrazine, and metolachlor (and selected degradates), respectively. Base-flow flux of alachlor and metolachlor is <3% of the total base-flow flux of those compounds plus degradates. Base-flow flux of nitrate and herbicides as a percentage of applications is typically highest in well-drained areas and lowest in areas with abundant poor drainage and anoxic conditions. In Coastal Plain watersheds of Albemarle and Pamlico Sounds, <2% of applied nitrogen reaches headwater streams as base flow. On the Delmarva Peninsula part of the Chesapeake Bay watershed, however, more than 10% of such applications are transported through groundwater to streams, and base-flow nitrate flux represents 70% of total nitrogen flux in headwater streams.

Modeling the longitudinal variation in wood specific gravity of planted loblolly pine (Pinus taeda) in the United States

Loblolly pine (Pinus taeda L.) is a major plantation species grown in the southern United States, producing wood having a multitude of uses including pulp and lumber production. Specific gravity (SG) is an important property used to measure the quality of wood produced, and it varies regionally and within the tree with height and radius. SG at different height levels was measured from 407 trees representing 135 plantations across the natural range of loblolly pine. A three-segment quadratic model and a semiparametric model were proposed to explain the vertical and regional variations in SG. Both models were in agreement that a stem can be divided into three segments based on the vertical variation in SG. Based on the fitted models, the mean trend in SG of trees from the southern Atlantic Coastal Plain and Gulf Coastal Plain was observed to be higher than in other physiographical regions (Upper Coastal Plain, Hilly Coastal Plain, northern Atlantic Coastal Plain, and Piedmont). Maps showing the regional variation in disk SG at a specified height were also developed. Maps indicated that the stands in the southern Atlantic Coastal Plain and Gulf Coastal Plain have the highest SG at a given height level.

Trends and Transformation of Nutrients and Pesticides in a Coastal Plain Aquifer System, United States

Four local-scale sites in areas with similar corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] agriculture were studied to determine the effects of different hydrogeologic settings of the Northern Atlantic Coastal Plain (NACP) on the transport of nutrients and pesticides in groundwater. Settings ranged from predominantly well-drained soils overlying thick, sandy surficial aquifers to predominantly poorly drained soils with complex aquifer stratigraphy and high organic matter content. Apparent age of groundwater, dissolved gases, N isotopes, major ions, selected pesticides and degradates, and geochemical environments in groundwater were studied. Agricultural chemicals were the source of most dissolved ions in groundwater. Specific conductance was strongly correlated with reconstructed nitrate (the sum of N in nitrate and N gas) (R(2) = 0.81, p < 0.0001), and is indicative of the relative degree of agricultural effects on groundwater. Trends in nitrate were primarily related to changes in manure and fertilizer use at the well-drained sites where aquifer conditions were consistently oxic. Nitrate was present in young groundwater but completely removed over time through denitrification at the poorly drained sites where there were variations in chemical input and in geochemical environment. Median concentrations of atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine), metolachlor (2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide), and some of their common degradates were higher at well-drained sites than at poorly drained sites, with concentrations of degradates generally higher than those of the parent compounds at all sites. An increase in the percentage of deethylatrazine to total atrazine over time at one well-drained site may be related to changes in manure application.

Recent mosasaur discoveries from New Jersey and Delaware, USA: stratigraphy, taphonomy and implications for mosasaur extinction

AbstractThe Upper Cretaceous deposits of New Jersey and Delaware produced the first mosasaur specimens collected in North America. Recent recovery of mosasaur specimens from streambank exposures and new excavation sites has increased our knowledge of the stratigraphic distribution of these animals in the northern Atlantic coastal plain. Reassessment of the source and age of mosasaur specimens from the Big Brook site and other localities in Monmouth County (NJ) has greatly increased the number of known Campanian mosasaur specimens from this region. Two main taphonomic occurrence modes are noted: 1 - single, worn and broken bones and isolated teeth in mixed faunal deposits probably accumulated due to current action in nearshore environments; 2 - partial skeletons, skulls and single bones in deeper-water settings were the aftermath of biological modification of carcasses and deadfalls. The mosasaurs of the New Egypt Formation represent some of the last (i.e., stratigraphically highest) mosasaur fossils in North America. Mosasaur extinction was due to the collapse of the rich Late Cretaceous marine food web at the K/T boundary. Subsequently in the early Paleocene, with the disappearance of the mosasaurs, crocodilians became the apical predators of the marine environment in this area.

Escalation in Late Cretaceous-early Paleocene oysters (Gryphaeidae) from the Atlantic Coastal Plain

More than 1600 valves of Late Cretaceous and early Paleocene Northern Atlantic Coastal Plain gryphaeid oysters (Exogyrinae and Pycnodonteinae) were examined for breakage-induced shell repair and morphologic variability to evaluate the hypothesis of escalation. The Exogyrinae show disproportionately higher average repair frequency (0.41) relative to the ecologically and functionally similar unornamented pycnodonts (0.19). An increase in repair frequency (independent evidence of the action of a selective agent, e.g., predation) through the stratigraphic interval supports escalation. Variation in repair frequencies may reflect differences in oyster morphology and in the strength and diversity of shell crushers across an onshore-offshore gradient. Escalation of antipredatory adaptation characterized the evolutionary response of gryphaeid oysters to their durophagous predators. Adaptation generally occurred by the enhancement of existing traits in both oyster lineages. Characters that confer a selective advantage against predators are not all expressed or improved concurrently in both oyster lineages. Morphologic adaptations to minimize shell breakage include the development of expansive, broad commissural shelves, thickened valves, and surface ornamentation (Exogyrinae). Surface ornament in the Exogyrinae gradually increased with time. For some characters, such as thickness, conflicting functional demands (e.g., valve stabilization) may have limited adaptation to predators.

Geohydrology and simulation of ground-water flow in the Northern Atlantic Coastal Plain aquifer system : P. P. Leahy & M. Martin, US Geological Survey Professional Paper, 1404-K, 1993, 81 pp

Geohydrology and simulation of ground-water flow in the Northern Atlantic Coastal Plain aquifer system : P. P. Leahy & M. Martin, US Geological Survey Professional Paper, 1404-K, 1993, 81 pp

Selective extinction and survival across the Cretaceous/Tertiary boundary in the northern Atlantic Coastal Plain

The inner Atlantic Coastal Plain in New Jersey and the Delmarva Peninsula is underlain by an Upper Cretaceous-lower Tertiary sequence of marine and paralic sand, clay, and glauconitic beds. Campanian, Maastrichtian, Danian, and Thanetian deposits are especially fossiliferous and yield a succession of marine faunas that reveal a pattern of selective extinction and survival across the Cretaceous/Tertiary (K/T) boundary in this area. Cretaceous benthic invertebrate communities are dominated by oysters and other semi-infaunal and infaunal molluscs with planktotrophic larval stages. These are replaced in the Danian by brachiopod-dominated communities that are composed of epifaunal benthos with a variety of nonplanktotrophic reproductive strategies. A similar pattern is observable in the nektonic cephalopod populations in this sequence; the typical ammonites of the Cretaceous became extinct at the K/T boundary, whereas the nautilids survived. Ammonites are thought to have had a planktotrophic larval stage, whereas nautilids are known to lay large lecithotrophic eggs. This pattern of differential survival is attributed to the planktonic population crash at the K/T boundary which placed planktotrophically reproducing species at a disadvantage while favoring the varied groups that practiced alternative reproductive strategies.

Distribution Patterns of Foliose and Fruticose Lichens of Eastern Iowa

Seventy-two species offoliose and fruticose lichens are reported for eastern Iowa, ten of them new records for the state. This flora shows greatest affinity with the eastern North American floristic region and has few species with a boreal, tropical or southwestern U.S. distribution. Until recently, the lichen flora of Iowa was largely unreported. However, in the last five years, several studies (Malone & Tiffany 1978; Schutte 1979; Dunlap & Tiffany 1980) on either a statewide or local level have provided a floristic base for lichen study in this area. Because of its central location, Iowa exhibits floristically diverse vascular plants, with elements of the tallgrass prairie, eastern deciduous forest, northern coniferous forest and Atlantic coastal plain being most common (Lammers & Van Der Valk 1978). However, ecological diversity has been reduced by extensive farming. Original or second-growth vegetation does remain in state and county parks and pre- serves, and along rivers where the land is unsuitable for agricultural use. Upland forests are dominated by Quercus, Carya, and Juglans, while lowland forests contain more Acer, Tilia, and Ulmus (now declining). These woodlands have few native conifers, although Juniperus virginiana may be frequent in dry sites. There are some stands of native Pinus strobus, and groves of non-native conifers have been planted in many areas. Very little native Iowa prairie remains, although a few communities of tallgrass prairie have been preserved. Most of the rock available for saxicolous lichens in eastern Iowa is limestone, found in outcrops along river valleys. Bryophytes also find these limestones suitable habitat, and lichens may be epiphytic on the bryophytes. Soils vary from the alfisols of the forests to the mollisols of the tallgrass prairie, but the sand prairie communities have the most extensive terricolous lichen assemblage. These soils are generally coarse to fine sand, with little organic matter, and rapid drainage. The purpose of this study is to present an annotated flora of the foliose and fruticose lichens of eastern Iowa, and to examine the affinities of this flora with other areas of North America.

The Portwashingtonian warm interval in the northern Atlantic coastal plain

Stratified and deformed masses of marine sediment that range in age from 43,800 to 21,750 yr were deposited in the Woodfordian moraine on western Long Island, New York. Reconstruction of the geologic history of these sediments provides further evidence of a mid-Wisconsinan warm interval, the Portwashingtonian warm interval (new name), that is represented by warm climate, temperate forests, and relative sea level comparable to modern sea level.

Moderate-temperature geothermal resource potential of the northern Atlantic Coastal Plain

Analysis of geothermal gradients determined in 65 exploratory holes in the Atlantic Coastal Plain indicates that in many areas temperatures exceed 40 °C at the base of the sediments. Water of such temperature, if it is available in sufficient quantity, represents a viable geothermal resource. Preliminary results of a test at Crisfield, Maryland, are encouraging in that brackish water at a temperature of 56 °C was produced from an aquifer at 1.2 km depth. Further testing of the temperatures and transmissivity of the deep aquifers beneath the Coastal Plain is required before the geothermal resource potential can be evaluated.

Glauconites from New Jersey–Maryland Coastal Plain: Their K-Ar Ages and Application in Stratigraphic Studies

Glauconite samples from various stratigraphic levels in the northern Atlantic Coastal Plain were dated by the K-Ar method. Twenty-eight samples were collected from glauconite-bearing sands in four traverses across the outcrop belt of Upper Cretaceous–lower Tertiary formations from northern New Jersey to eastern Maryland, thus providing a framework on which to test the reliability of glauconite for dating in vertical sequences and within some formations along strike. Sample ages were determined paleontologically and radiogenically. The results show that most radiogenic determinations of glauconite followed a systematic pattern; the resultant ages were generally younger upward through the Stratigraphic section. In addition, consistent ages were obtained from many of the stratigraphic units along strike. A combination of paleontologically derived ages and the numerical radiogenic ages suggests that the stages of the Late Cretaceous are unequal rather than equal as some have proposed. For example, Campanian and Paleocene times are of significantly greater duration than the Maestrichtian. Several samples obtained across the Cretaceous-Tertiary boundary indicate that the age of the boundary is between 63.2 and 59.1 m.y., probably very near 61.1 m.y. Dates considered to be reliable were obtained from 25 of 28 samples. Two of the three discordant ages are ascribed to incomplete glauconitization of the pre-existing mineral phase and hence to mineral impurity. No adequate explanation for the third significantly younger age has been determined.

Late Mesozoic-Cenozoic Tectonic Aspects of the Atlantic Coastal Margin

Data from the middle and northern Atlantic Coastal Plain of the United States and continental slope show that the dominant filling of the Atlantic margin geosyncline occurred in pre-latest Cretaceous time with only thin additions of Cenozoic strata. The influx of significant amounts of detrital material into the offshore areas had largely ceased by latest Cretaceous time, was essentially absent in the early Cenozoic, but increased considerably in the Miocene, indicating a rejuvenation of the Appalachian source area. Basin migration continued throughout the Cenozoic, and the Miocene and Eocene strata are used to illustrate the shifting of the loci of deposition. The distributions of the strata indicate that local to regional tectonic movements are responsible. Comparison with the Gulf Coast geosyncline shows that, although features such as sedimentary thickness, evaporites, and volcanic materials are generally similar between the two margins, major differences in time of filling and regional tectonic movements exist.

MORPHOLOGICAL AND ECOLOGICAL STUDY OF PHYSODERMA DULICHII

A B S T R A C T A new species of aquatic Phycomycete, Physoderma dulichii Johns, parasitic on the aquatic sedge Dutlichium arundinaceum (L.) Britt., is described from northern Michigan. This parasite infects and kills the upper epidermal cells of the host leaves. Macroscopically, infection by P. dulichii is indicated by striking brown bands with irregular margins, at intervals on the upper surfaces of the leaves. Like other species of Physoderma, this organism's development includes two distinct phases, an epibiotic monocentric phase producing asexual zoospores and an endobiotic polycentric phase bearing thick-walled resting spores that germinate after an extensive period of maturation at low temperature ta form zoospores. The morphology and development of the two phases and of resting spore germination are reported in detail. Only the immature leaves of the host are susceptible to infection, which may be initiated by the introduction of mature resting spores, zoospores from germinated resting spores, or zoospores from epibiotic sporangia. Resting-spore zoospores may also produce the endobiotic stage directly. Initiation of infection in nature requires that the terminal cluster of immature leaves on the host plant be submerged, but infection of subsequently formed leaves of emergent culms can be accomplished through the agency of zoospores from epibiotic sporangia on older leaves. The relation of infected stands of hosts to their environment is discussed and the importance of standing water to infection noted. The geographical distribution of the parasite shows correlation with the drainage basins of the Great Lakes, the St. Lawrence River, and the northern Atlantic Coastal Plain

Hydrochemical Facies and Ground-Water Flow Patterns in Northern Atlantic Coastal Plain: ABSTRACT

Hydrochemical facies is used in this paper to denote the diagnostic chemical aspect of ground-water solutions occurring in hydrologic systems. They reflect the chemical response of the interrelated effects of the lithology and the pattern of ground-water flow. The facies and their distribution are shown on trilinear diagrams, isometric panel diagrams, and maps showing isopleths of chemical constituents within certain formations. The occurrence of the various facies within one formation or group of formations in which the mineralogy is uniform indicates that the flow of characteristics of the aquifer systems controls the distribution of the hydrochemical facies. By use of available head data, flow patterns of the fresh ground water are shown on maps and cross sections. The e patterns are controlled in part by the distribution of higher landmasses and the depth to bedrock or to the salt-water interface. Mapping of the hydrochemical facies shows that at shallow depths (less than about 200 feet) the calcium-magnesium cation facies generally predominates in the northern Atlantic Coastal Plain. The bicarbonate anion facies occurs more widely in the shallow deposits of the Coastal Plain than does the sulphate or chloride End_Page 1244------------------------------ facies. In the deeper deposits the sodium chloride facies predominates. The lower total dissolved solids in the ground water in New Jersey indicates that less upward vertical leakage occurs there than in Maryland and Virginia where the shallow deposits contain more concentrated solutions. End_of_Article - Last_Page 1245------------

Pre-Matawan Cretaceous Sediments: ABSTRACT

The record of the post-Jurassic transgression which caused the formation of the northern Atlantic Coastal Plain begins with the Potomac group, non-marine sediments of early Cretaceous age. Lithologically similar non-marine and transitional sediments of early late Cretaceous age, the Raritan and Magothy formations, overlie the Potomac group. The lithologic similarity of the several formations, and disagreement as to the significance of their contained plant fossils, which are the major means of dating the exposed deposits, have caused some recent confusion in their stratigraphic interpretation. Recent laboratory and field studies show that heavy minerals are useful for local correlation, and permit the following conclusions. 1. A considerable wedge of Lower Cretaceous sediments is present in the shallow subsurface of southern New Jersey, and was derived principally from the crystalline Piedmont of Pennsylvania and Delaware. 2. During Raritan time the Piedmont was covered by Cretaceous sediments and the materials which make up the Raritan formation were supplied from older sedimentary terranes northwest of the Coastal Plain except in the northern New Jersey-Long Island area which received sediments derived from crystalline rocks exposed in southern New York and New England. Similar conditions prevailed during the deposition of the Magothy formation, but during Magothy time, the Cretaceous sediments were stripped from the Piedmont and it again became a site of active erosion. 3. The Potomac group and the Raritan formations are dominantly fluvial sediments at the outcrop and in the shallow subsurface, but marine facies of the Raritan are present only a few miles downdip from the outcrop areas. No marine Lower Cretaceous has been reported from the northern Atlantic Coastal Plain. The Magothy formation is transitional marine at the outcrop. End_of_Article - Last_Page 1253------------