Geology of the Coastal Plain of North Carolina

Richards, Horace G.

doi:10.2307/1005638

Cited by 32 publications

(16 citation statements)

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“…1c), stretches from Georgia (GA) to South Carolina (SC) and North Carolina (NC). Here, numerous studies dating back a half century (Richards, 1963) have identified an almost continuous scarp (Orangeburg Scarp, Ator et al, 2005;Cronin et al, 1984;Huddlestun, 1988;Winker and Howard, 1977) extending from Georgia to Virginia that is interpreted as the geomorphic imprint of the maximum middle-late Pliocene SL ingression (Huddlestun, 1988;Winker and Howard, 1977). In NC and SC the scarp is associated with the Duplin Formation, representing a warm, shallow, normal marine, inner to middle-shelf facies of Mid-Pliocene age (Parnell and Visaggi, 2011), while in northern GA coeval deposits have been associated with the Raysor Formation (Huddlestun, 1988), representing a slightly deeper marine environment than the Duplin (Markewich et al, 1992;Ward et al, 1991).…”

Section: Observed Sea-level Markersmentioning

confidence: 99%

The Mid-Pliocene sea-level conundrum: Glacial isostasy, eustasy and dynamic topography

Rovere

Raymo

Mitrovica

et al. 2014

Earth and Planetary Science Letters

112

126

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Available online xxxx Editor: J. Lynch-Stieglitz Keywords: Mid-Pliocene sea level Australia Republic of South Africa southeast coast USA dynamic topography isostasyDetermining eustatic sea level during the Mid-Pliocene warm period (∼3.3 to 2.9 Ma) has been a central but elusive goal in the study of past warm climates. Estimates of eustatic sea level based on geologic data span a broad range; variation that we now recognize is due in part to geographically varying post-depositional displacement caused by glacial isostatic adjustment and dynamic topography. In this study, we combine field observations and glacial isostatic adjustment modeling to estimate the dynamic topography signal in three areas that are important to paleo-sea level studies of the Mid-Pliocene warm period (South Africa, West Australia and southeastern United States). We show that dynamic topography played a significant role in the post-depositional displacement of Pliocene, and even younger Pleistocene, shorelines. In this regard, we provide a robust paleo-sea level elevation data set, corrected for glacial isostatic adjustment, that can be used to evaluate predictions from mantle flow models of dynamic topography.

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Section: Observed Sea-level Markersmentioning

confidence: 99%

The Mid-Pliocene sea-level conundrum: Glacial isostasy, eustasy and dynamic topography

Rovere

Raymo

Mitrovica

et al. 2014

Earth and Planetary Science Letters

112

126

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“…But as seismic profiling and deep drilling revealed the variable depth to basement along the coastline (Richards, 1950;Spangler, 1950;Spangler and Peterson, 1950), Cederstrom's concept was transformed. Realizing that the basement was considerably higher near Ft. Monroe (across the James River from Norfolk) than to the north and south, Richards and Straley (1953) introduced the term Ft. Monroe high.…”

Section: Arches and Basinsmentioning

confidence: 99%

The Chesapeake Bay bolide impact: a convulsive event in Atlantic Coastal Plain evolution

Poag

1997

Sedimentary Geology

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Until recently, Cenozoic evolution of the Atlantic Coastal Plain has been viewed as a subcyclical continuum of deposition and erosion. Marine transgressions alternated with regressions on a slowly subsiding passive continental margin, their orderly succession modified mainly by isostatic adjustments, occasional Appalachian tectonism, and paleoclimatic change. This passive scenario was dramatically transformed in the late Eocene, however, by a bolide impact on the inner continental shelf. The resultant crater is now buried 400-500 m beneath lower Chesapeake Bay, its surrounding peninsulas, and the continental shelf east of Delmarva Peninsula. This convulsive event, and the giant tsunami it engendered, fundamentally changed the regional geological framework and depositional regime of the Virginia Coastal Plain, and produced the following principal consequences. (1) The impact excavated a roughly circular crater, twice the size of Rhode Island (-6400 km2) and nearly as deep as the Grand Canyon (-1.3 km deep). (2) The excavation truncated all existing ground-water aquifers in the target area by gouging -4300 km3 of rock from the upper lithosphere, including Proterozoic and Paleozoic crystalline basement rocks and Middle Jurassic to upper Eocene sedimentary rocks. (3) Synimpact depositional processes, including ejecta fallback, massive crater-wall failure, water-column collapse, and tsunami backwash, filled the crater with a porous breccia lens, 600-1200 m thick, at a phenomenal rate of -1200 m/hr. The breccia lens replaced the truncated ground-water aquifers with a single 4300 km3 reservoir, characterized by ground water -1.5 times saltier than normal sea water (chlorinities as high as 25,700 mg/l). (4) A structural and topographic low, created by differential subsidence of the compacting breccia, persisted over the crater at least through the Pleistocene. In the depression are preserved postimpact marine lithofacies and biofacies (upper Eocene, lower Oligocene, lower Miocene) not known elsewhere in the Virginia Coastal Plain. (5) Long-term differential compaction and subsidence of the breccia lens spawned extensive fault systems in the postimpact strata. Many of these faults appear to reach the bay floor, and may be potential hazards for motion-sensitive structures in population centers around Chesapeake Bay. Near-surface fracturing and faulting generated by the impact shock may extend as far as 90 km from the crater rim. (6) Having never completely filled with postimpact sediments. the sea-floor depression over the crater appears to have predetermined the location of Chesapeake Bay. (7) As large impact craters are principal sources for some of the world's precious metals, it is reasonable to expect that metal-enriched sills, dikes, and melt sheets are present in the inner basin of the crater.In addition to these specific consequences, the crater and the convulsive event that produced it, have widespread implications for traditional interpretations of certain structural and depositional features of the Atla...

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“…1). It is underlain by a series of wedge-shaped strata of poorly consolidated materials approximately 660 m deep, lying over crystalline basement rock (Richards 1950) . These strata, including the Pungo River formation, an interbedded layer of phosphatic and nonphosphatic sands, silts, clays, and limestones, were produced by a series of Tertiary submergences and emergences (Kimrey 1965, Stuckey 1965.…”

Section: Geology and Soilsmentioning

confidence: 99%

Dry Matter Production in Young Loblolly (Pinus Taeda L.) and Slash Pine (Pinus Elliottii Engelm.) Plantations

Nemeth¹

1973

Ecological Monographs

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The net primary productivity of the pine species and lesser vegetation (herbaceous ground cover) plus turnover rates between the litter layer and soil organic matter were investigated in young loblolly and slash pine plantations in Beaufort County, North Carolina. Estimations of the aboveground tree biomass and production by components were made by applying multiple regression, weight—prediction equations developed from harvest data (15 slash pine and 41 loblolly pine trees) to tree dimensions from 28 permanent, undisturbed plots. Optimal plot size was determined by time—cost analysis. Total biomass for slash pine ranged from 5.2 mt/ha and 9.9 kg/tree (age 4) to 31.7 mt/ha and 29.8 kg/tree (age 8), and loblolly pine ranged from 4.2 mt/ha and 4.7 kg/tree (age 4) to 107.6 mt/ha and 82.7/tree (age 12). Net production for slash pine was greater than loblolly pine and ranged from 3.9 mt/ha per year and 8.0 kg/tree per year (age 4) to 12.3 mt/ha per year and 11.6 kg/tree per year (age 8). Loblolly pine produced from 4.3 mt/ha per year and 4.8 kg/tree per year (age 4) to 4.1 mt/ha per year and 4.3 mt/ha per year (age 8). Net primary production of loblolly pine was 22.3 mt/ha per year and 18.8 kg/tree per year at age 10 and 11 and dropped to 18.4 mt/ha per year and 13.6 kg/tree per year at age 12. The decrease in production rate of loblolly pine at age 12 was correlated with a decrease in branch needle biomass as canopy closure progressed. Five root systems were excavated, and percentage of aboveground tree biomass was used to calculate root biomass and production. Canopy closure also caused a decrease in net primary production of the lesser vegetation from 1.8 mt/ha per year in the open stands to 0.2 mt/ha per year under closed stands. Simultaneously, the ground—litter component increased from 3.7 to 5.8 mt/ha through litter fall, and the turnover rate to the soil decreased. Soil organic matter accounted for 88% (102.0 mt/ha) to 52% (124.0 mt/ha) of total plot biomass in the youngest and oldest stands, respectively. Caloric analysis was done on all plant material and ground litter. The results are presented as net primary production and turnover rates (109 cal/ha per year).

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Geology of the Coastal Plain of North Carolina

Cited by 32 publications

References 0 publications

The Mid-Pliocene sea-level conundrum: Glacial isostasy, eustasy and dynamic topography

The Mid-Pliocene sea-level conundrum: Glacial isostasy, eustasy and dynamic topography

The Chesapeake Bay bolide impact: a convulsive event in Atlantic Coastal Plain evolution

Dry Matter Production in Young Loblolly (Pinus Taeda L.) and Slash Pine (Pinus Elliottii Engelm.) Plantations

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