Hydrogeologic controls on peatland development in the Malloryville Wetland, New York (USA)

The Malloryville Wetland Complex, a small kettle-hole peatland, contains a diversity of peatland types. The wetland has a ‘rich’ side that contains wetland vegetation associated with solute-rich, near-neutral pH (minerotrophic) water, and a ‘poor’ side containing vegetation that grows in solute-poor and acidic (ombrotrophic) water. Vertical head gradients at piezometer clusters located in the rich side clearly show that groundwater is moving upwards towards the land surface, consistent with the vegetation types and surface water quality. In contrast, vertical head gradients also show that groundwater is moving upward in the poor side even though the vegetation and surface water chemistry are not minerotrophic. An incipient raised bog in the center of the poor side is the only site where groundwater moves consistently downward.

A peat core collected at the bog center shows that the bog site was initially covered by minerotrophic vegetation, typically found in groundwater discharge zones, which was later replaced by ombrotrophic bog vegetation. Theoretical computer simulation experiments of the bog hydrogeologic setting through time suggest that the direction of vertical groundwater flow at the bog site permanently changed from up to down when a water table mound developed under a convex-shaped fen peat mound that probably formed because of differential peat accumulation. Ombrotrophic conditions and bog vegetation probably began when the fen water table mound grew sufficiently large enough to divert the upward movement of regional groundwater. The transition from rich to poor environments probably occurred when the wetland water table was substantially below the elevation of the surrounding regional water table.     

A marine kill in New Jersey coastal waters

A kill of lobsters around wrecks off the New Jersey coast seem not to be a direct result of pollution but may have been due to an influx of water causing reduced oxygen levels combined with high temperatures. Mortalities of this kind have been observed before in the area but it is not known if this is an annual event or due to abnormal circumstances. It would be worth keeping the situation under review in the future.     

Analysis of Conceptual Designs for Remedial Measures at Lipari Landfill, New Jersey

During the two-week period from March 12 through March 26, 1982, a preliminary conceptual design analysis on various remedial measures for the Lipari Landfill, New Jersey, was performed. This site is currently ranked at the top of the EPA's Superfund Cleanup List. This report demonstrates the practical benefits and limitations of applying models (both analytical and numerical) to a hazardous waste site in a restricted period of time. The numerical model was used to simulate current flow conditions at the site and provide initial conditions for a series of sensitivity simulations. These sensitivity simulations were designed to test (1) a slurry wall, (2) drain location, (3) drain depth, and (4) a clay cap. Analytical solutions were designed to analyze (1) water in place, (2) flow through an underlying layer, the lower Cohansey, (3) draining the lower Cohansey, (4) flushing the contaminated area using wells, and (5) convective arrival time of contaminants to drains. This analysis quantified discharge to drains, flow rates to a swamp downstream of the landfill, time required to drain the landfill, and contaminant travel times that would result from the implementation of each of the remedial measures that were suggested. The conclusions from this study were used by engineers and planners who incorporated, economics and engineering decisions for the various remedial measures considered.     

Quantitative measures of textural anisotropy resulting from magmatic compaction illustrated by a sample from the Palisades sill, New Jersey

Early in the crystallization of many tholeiitic basaltic magmas, plagioclase crystals cluster together into a 3-D cellular network, which forms a passive marker capable of recording the deformation that accompanies compaction of crystal mush. Although irregular in detail, the overall network is initially isotropic and only becomes anisotropic as a result of compaction. We have developed four independent methods to quantify the 3-D textural anisotropy of a basalt sample using at least three non-parallel thin sections. Three of the methods are based on the geometrical properties of digitized maps of the feldspar chain networks. One approach focuses on the angular variation of the mean intercept along parallel traverses through the network, another examines the orientation and size distribution of individual links, and the third considers the average shape of interstitial regions outlined by the plagioclase network. The fourth technique approximates the textural anisotropy by the variogram anisotropy of a scanned thin section image. We illustrate the methods using five oriented non-parallel thin sections from a sample of diabase 146 m above the base of the 300-m-thick Palisades sill of New Jersey. Compaction of crystal mush in this sill has previously been postulated on the basis of chemical evidence. The 3-D feldspar network anisotropy based on the first three approaches suggests nearly uniaxial compaction on the order of 8.6% in a direction within 3° of the intersection of the columnar joints at the sample site. A rigorous statistical test based on the statistics of elliptically contoured non-normal multivariate distributions documents that the link-vector distribution in vertical sections are statistically anisotropic at a 95% confidence level and that the overall compaction is 7.9±2.6%. The orientation and magnitude of the 3-D textural anisotropy determined by the image variogram of the non-opaque minerals is almost identical to the mean feldspar network anisotropy; 8.5% compaction in a direction 10° from the columnar joint intersections. The major silicate textural and feldspar network anisotropy axes both plunge almost directly down dip of the sill. On the other hand, the major axis of the variogram anisotropy of the opaque minerals is approximately parallel to the strike of the sill and to the major axis of the anisotropic magnetic susceptibility. The anisotropy of the silicate mineral fabric may reflect down-dip flow of a deformable melt-rich crystal mush, whereas the AMS and opaque textural anisotropy reflects the influence of gravitational stresses during the growth of magnetite in the final stages of melt crystallization. Evidently the Palisades sill was not originally horizontal but was intruded in an orientation close to its present attitude.     

Geochemical evolution within a Devonian intra-oceanic island arc: The Gamilaroi terrane, southern New England orogen, Australia

Abstract Geochemical analyses of volcanic rocks in the Gamilaroi terrane reveal several phases of arc activity within an intra-oceanic island-arc terrane. Felsic volcanic rocks at the base of the section have rare earth element (REE) and trace element compositions which indicate that they were derived from an island-arc source. Basalts immediately overlying the felsic volcanic rocks have a distinctive geochemical signature with low levels of Ti and Y and high levels of Ni, Cr and Mg. Low concentrations of REE and trace elements relative to mid-ocean-ridge basalts (MORB) indicate that they were also derived from an intra-oceanic island-arc source. Extensive basalts and basaltic andesites among the youngest rocks of the terrane have typically flat to enriched REE and trace element compositions, indicating a transitional arc-back-arc source. The change in basalt compositions indicates that rifting had occurred by this stage in the evolution of the arc. Confirmation of an intra-oceanic setting for this terrane enables a more detailed comparison with similar intra-oceanic rocks in the northern New England orogen. This study of the Gamilaroi terrane is an example of the potential use of geochemical data to identify other ancient intra-oceanic island-arc-rift suites.     

Repeat Sampling and Coliform Bacteria Detection Rates in New Jersey Domestic Wells

In compliance with the New Jersey Private Well Testing Act, 78,546 wells (93,787 samples, including samples from 13,290 wells that were analyzed more than once) were analyzed for total coliform (TC) bacteria by one or more of 39 laboratories over a 10‐year period. Samples containing TC bacteria were further analyzed for the presence of either fecal coliform or E. coli (FC/EC) bacteria. The large population of wells sampled multiple times permitted a systematic study of the effect of repeat sampling on coliform bacteria detection rates. The detection rate increased with the number of times wells were sampled. In bedrock, TC bacteria were detected in 21% of the population of wells analyzed only once, 33% in the population sampled twice, and 43% in the population sampled three times. It was estimated that TC bacteria would be detected in 90% of all wells if each well was analyzed 10 times. For FC/EC bacteria, it was estimated that 21 and 68 samples, respectively, would be required to reach the 50% and 90% population detection rates. In the Coastal Plain (CP), many more samples would be required to achieve the same estimated population detection rates. The population detection rate estimates were also dependent on the type of method used, the pH of the well water, and the geologic formation in which wells were located. A single sample was not sufficient to detect coliform bacteria when present in well water.     

Topographic changes associated with coastal dune blowouts at island beach state park,New Jersey

Topographic changes in two blowouts located in Island Beach State Park, New Jersey, USA were monitored over the winter of 1981-1982. Elevation changes were measured with erosion pins, and sediment traps placed at comparable locations in each blowout monitored the amount of sand moved by the wind. Discrete wind events were identified from regional data, and morphological data for the intervals with the highest onshore and offshore wind speeds are examined in detail. Vegetation is the primary influence on the development of the two blowouts. Blowout A is characterized by eroding sidewalls, a stable base, and an accreting blowout rim. High rates of sediment transport occur through the blowout throat which results in accretion on the vegetated rim. This blowout is an active sediment transfer system. Vegetation causes a large amount of deposition in the throat of blowout B. As vegetation was buried over the winter, the area of deposition migrated inland. Sidewall erosion also occurred in blowout B. Little change was recorded on the blowout rim. Blowout B is a recovering system where sediment is delivered to the blowout floor from the beach by onshore winds and from the blowout rim by offshore winds where it is stabilized by vegetation. The development of foredune blowouts is governed largely by vegetation cover on the dune crest and by sidewall erosion during offshore and onshore winds. Blowout recovery depends on vegetation growth and sediment deposition in the throat, and on the role of the sidewalls as sources of sediment which is deposited elsewhere within the system. Foredune blowouts are dynamic systems in which positive feedbacks in sediment availability and vegetation growth lead to a cycle of development and closure.