Northeastern Geology and Environmental Sciences
v. 24, no. 3, 2002, September
abstracts
A STATISTICAL AND SPATIAL ANALYSIS OF DIOXIN-FURAN CONTAMINATION IN THE HUDSON ESTUARY
William J. Hansen
City University of New York Graduate Center, 365 5th Avenue, New York, NY;
Current Address: 71 Harris Road, Katonah, NY 10536; Fax: 212-637-3354; [email protected]
ABSTRACT: Sediment sampling results from a number of studies conducted in the Hudson Estuary were examined and evaluated for spatial and statistical patterns in dioxin concentration and dioxin congener patterns. Principal component analysis and cluster analysis were used to group the multitude of sediment samples and congeners into a smaller set of variables. The spatial distribution of these derived data were examined with respect to industrial activity in the area of interest, environmental regulation, cultural trends and industrial accidents. A Geographic Information System (GIS) was used to analyze sample points for spatial correlation with sources of dioxin contamination.
The results of these analyses indicate that current deposition of dioxin contamination in the Harbor Estuary is dominated by combustion sources, such as automobiles, trucks and to a more limited extent, municipal and industrial incineration. Subsurface samples show a more complex array of dioxin-furan congener patterns with numerous dioxin sources including combustion sources, chemical discharges and sewage treatment plants. The most significant single source of dioxin contamination in the Harbor Estuary is the former Diamond Alkali Site, on the Lower Passaic River. Long-term production of 2,4,5 trichlorophenoxy acetic acid (2,4,5-T) and an industrial accident in 1960 released massive amounts of dioxin contamination into the adjacent Passaic River. This contamination left a distinct dioxin-furan pattern; composed of primarily 2,3,7,8-tetrachlorinated dibenzo dioxin. Two specific patterns identified result from contamination at this site, one represents long term production of on-site 2,4,5-T, while the other is a unique signature from the 1960 explosion and fire. Although largely buried this hot spot of contamination is close to the surface in a number of locations. This represents a threat to biota due to the potential for reintroduction into biologically active zone as well as a barrier to human use of the Lower Passaic River for manufacturing and recreational boating.
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LANCASTER TRANSVERSE SEISMIC ZONE (PENNSYLVANIA): STRAIN CONCENTRATION AT LATERAL RAMPS OF BASEMENT NAPPES (?)
Donald U. Wise 1 and Rodger T. Faill 21Department of Geology and Geography, University of Massachusetts, Amherst MA 01003; [email protected]
2DCNR-Pennsylvania Geological Survey, 3240 Schoolhouse Road, Middletown. PA 17057-3534; [email protected]
ABSTRACT: A diffuse NNE-striking cluster of seismic activity in Lancaster and Berks Counties in southeastern Pennsylvania represents a minor but anomalous seismic zone that lies transverse to the regional Paleozoic and Mesozoic ENE-trending structural grain. Despite the shallowness of the quakes, there is little clear relationship to mapped surface structures. One possible model involves the shallow WSW termination of basement slabs, in effect their lateral ramp zones, now embedded within the larger Paleozoic Reading meganappe system. Strength contrast between these strong basement slabs with respect to cocoons of weaker shales and carbonates of the enclosing nappes concentrates present-day regional ENE compressive stresses at their ends and stores larger elastic strains within this zone. Similar but less intense processes within rather than at the ends of these stronger slabs may account for the shallow Newark Basin Seismic Zone extending ENE along the external basement massifs of the Reading Prong.
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MODELING SEDIMENT FLUX FROM BIRCH BROOK, AN UNDISTURBED CATCHMENT IN NORTHWESTERN MASSACHUSETTS
William B. Ouimet1 and David P. Dethier2
1Department of Geosciences, Williams College, Williamstown, MA 01267; [email protected]
2Department of Geosciences, Williams College, Williamstown, MA 01267
ABSTRACT: Discharge and annual bedload measurements from the 1.25 km2 South Branch of Birch Brook, NW Massachusetts, show that the annual flux of bedload was 2.0 tons km-2 yr-1 from this forested basin between 1986 and 2000. Sediment transport in the South Branch is controlled by discharge events above bankfull (0.34 m3 s-1) and the relative availability of sediment in the stream channel, particularly material stored by organic debris dams. Peak discharge events explain 91% of the variance in measured sediment discharge on the South Branch during the period 1986 to 1996. After 1996, however, correlation is poor, reflecting a change in sediment availability after sediment year 1996, when sediment flux was 5 times average values.
Analyzing the sediment budget for the Birch Brook catchment permits us to speculate about how deforestation, grazing and cultivation in the 19th century affected hillslope erosion and stream sediment load. Higher sediment loads during the past century may have produced the low terraces that line the lower reaches of Birch Brook. The present rate of sediment transport from the Birch Brook catchment suggests that the erosion rate from forested catchments in NW Massachusetts is low.
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CHERTY SPONGE REEFS IN THE DEVONIAN ONONDAGA LIMESTONE:
NEWLY DISCOVERED GAS RESERVOIR IN PENNSYLVANIA
1Kathy R. Bruner and 1Richard Smosna
1Department of Geology & Geography, Box 6300, West Virginia University, Morgantown, WV 26506
ABSTRACT: Recent wells drilled to the Onondaga Limestone in northwestern Pennsylvania have encountered previously unknown sponge reefs comprised of porous chert and nonporous limestone. The chert represents fossil sponges--small globular encrusting masses with large numbers of spicules--that underwent neomorphism from biogenic opal to microcrystalline quartz. Abundant calcitic material has been incorporated into the chert masses, presumably calcareous sediment taken into the sponges' body by the organisms themselves. In addition, thin beds of skeletal-peloidal grainstone occur within and over the reef rock.
The porous chert masses range in size up to several centimeters. Most of the pore volume, and up to 18% of the total rock volume, consists of open tubes having the same shape and size as the siliceous monaxon spicules (straight cylinders, 150-800 m long, 10-110 m in diameter). Inside a single sponge, the tubular pores are relatively uniform in size and commonly exhibit a parallel orientation. These pores clearly represent the molds of dissolved spicules. Additional pore types in the chert include micropores, small vugs, and microfractures. Total porosity, however, has been significantly reduced by physical compaction as well as cementation by chert, calcite, collophane, and bitumen.
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(not all papers had abstracts)