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Lawrence J. Poppe

Publications and source records attributed to Lawrence J. Poppe.

43 records · Page 3Linked to original sources
USGS1993

Ground water discharge and the related nutrient and trace metal fluxes into Quincy bay, Massachusetts

Measurement of the rate and direction of ground water flow beneath Wollaston Beach, Quincy, Massachusetts by use of a heat-pulsing flowmeter shows a mean velocity in the bulk sediment of 40 cm d −1 . The estimated total discharge of ground water into Quincy Bay during October 1990 was 1324–2177 m 3 d −1 , a relatively low ground water discharge rate. The tides have only a moderate effect on the rate and direction of this flow. Other important controls on the rate and volume of ground water flow are the limited thickness, geographic extent, and permeability of the aquifer. Comparisons of published streamflow data and estimates of ground water discharge indicate that ground water makes up between 7.4–12.1% of the gaged freshwater input into Quincy Bay. The data from this study suggest the ground water discharge is a less important recharge component to Quincy Bay than predicted by National Urban Runoff Program (NURP) models. The high nitrate and low nitrite and ammonia concentrations in the ground water at the backshore well sites and low nitrate and high nitrite and ammonia concentrations in the water flowing from the foreshore suggests that denitrification is active in the sediments. The low ground water flow rates and low nitrate concentrations in the foreshore samples suggest that little or no nitrate is surviving the denitrification process to affect the planktonic community. Similarly, oxidizing conditions in the aquifer and low trace metal concentrations in the ground water samples suggest that the metals may be precipitating and binding to sedimentary phases before impacting the bay.

Massachusetts↗
USGS1992

Deep Sea Drilling Project Site 612 bolide event: New evidence of a late Eocene impact-wave deposit and a possible impact site, US east coast

A remarkable >60-m-thick, upward-fining, polymictic, marine boulder bed is distributed over >15 000 km 2 beneath Chesapeake Bay and the surrounding Middle Atlantic Coastal Plain and inner continental shelf. The wide varieties of clast lithologies and microfossil assemblages were derived from at least seven known Cretaceous, Paleocene, and Eocene stratigraphic units. The supporting pebbly matrix contains variably mixed assemblages of microfossils along with trace quantities of impact ejecta. The youngest microfossils in the boulder bed are of early-late Eocene age. On the basis of its unusual characteristics and its stratigraphic equivalent to a layer of impact ejecta at Deep Sea Drilling Project (DSDP) Site 612. It is postulated that this boulder bed was formed by a powerful bolide-generated wave train that scoured the ancient inner shelf and coastal plain of southeastern Virginia.

Geology↗
USGS1981

Sediment parameters for a fine-grained sediment deposit on the southeastern New England continental shelf

An area of fine-grained sediments south of Martha's Vineyard, Massachusetts, has been interpreted as a contemporary deposit. Textural analysis of cores from this area indicates that the deposit consists of sandy to clayey silts overlying a well sorted relict sand. The maximum thickness of the fine sediments is about 6 meters as determined from a core near the center of this deposit. The mineralogy of the <2 um size fraction is similar in both the fine sediments of the contemporary deposit and the underlying coarse sands. The assemblage consists of about 60% illite, 20% chlorite, and 10% kaolinite with minor amounts of mixed-layered clay and smectites. Heavy mineral analysis from a core near the center of the deposit reveals that opaque minerals, framboidal pyrite, muscovite, hornblende, garnet, and tourmaline constitute over 65% of the total downcore assemblage. Pyrite concentrations vary widely at some intervals and may reflect areas of micro-reducing conditions within the core or changes in source area with time. A persistent mica content indicates the presence of a low-energy environment throughout the depositional history of these fine sediments. Downcore organic carbon concentrations are generally uniform in the fine sediments and average about 1.5 percent. Surficial concentration from a core near the center of this feature is about 10 times greater than concentrations for coarse-grained sands on the surrounding shelf.

New England continental shelf↗
USGS1981

Data file: the 1976 Atlantic Margin Coring (AMCOR) Project of the U.S. Geological Survey

In 1976, the U.S. Geological Survey conducted the Atlantic Margin Coring Project (AMCOR) to obtain information on stratigraphy, hydrology and water chemistry, mineral resources other than petroleum hydrocarbons, and geotechnical engineering properties at sites widely distributed along the Continental Shelf and Slope of the Eastern United States (Hathaway and others, 1976, 1979). This program's primary purpose was to investigate a broad variety of sediment properties, many of which had not been previously studied in this region. Previous studies of sediments recovered by core drilling in this region were usually limited to one or two aspects of the sediment properties (Hathaway and others, 1979, table 2). The AMCOR program was limited by two factors: water depth and penetration depth. Because the ship selected for the program, the Glomar Conception , lacked dynamic positioning capability, its anchoring capacity determined the maximum water depth in which drilling could take place. Although it was equipped to anchor in water 450 m deep and did so successfully at one site, we attmepted no drilling in water depths greater than 300 m. Strong Gulf Stream currents at the one attempted deep (443 m) site frustrated attempts to "spud in" to begin the hole.

Open-File Report↗