Browsing by Author "Plank, M.O."
Now showing 1 - 7 of 7
Results Per Page
Sort Options
Item Bedrock Geologic Map Of The Piedmont OF Delaware And The Adjacent Pennsylvania(Newark, DE: Delaware Geological Survey, University of Delaware, 2000) Schenck, W.S.; Plank, M.O.; Srogi, L.A.Item Bedrock Geology Of The Piedmont Of Delaware And Adjacent Pennsylvania(Newark, DE: Delaware Geological Survey, University of Delaware, 2000) Plank, M.O.; Schenck, W.S.; Srogi, L.A.This report accompanies a new map that revises the original bedrock geologic maps of the Delaware Piedmont compiled by Woodruff and Thompson and published by the Delaware Geological Survey (DGS) in 1972 and 1975. Combined detailed mapping, petrography, geochemistry, and U-Pb geochronology have allowed us to redefine two rock units and formally recognize eleven new units. A section of the Pennsylvania Piedmont is included on the new map to show the entire extent of the Mill Creek Nappe and the Arden Plutonic Supersuite.Item Data Report On Rock Cores From Red Mill Road, Harmony Road, Prices Corner, And Newport, Delaware(Newark, DE: Delaware Geological Survey, University of Delaware, 1995-06) Schenck, W.S.; Plank, M.O.The Delaware Piedmont is underlain by metamorphosed sedimentary and igneous rocks of Middle Proterozoic to Paleozoic age. The rocks have been studied for many years, but because of poor exposure, high-grade metamorphism, and intense deformation, it has been difficult to identify units, understand their stratigraphic relationships to one another, and determine their origin and history; however, northern Delaware occupies a critical position in the central Appalachian Piedmont, and understanding its geology is key to understanding the geology of this region.Item Delaware Piedmont Geology(Newark, DE: Delaware Geological Survey, University of Delaware, 1998) Plank, M.O.; Schenck, W.S.The Red Clay Creek Valley traverses geologic features that have long been recognized as important to science, industry, and history. The reader will note that within the text “Piedmont,” and “Atlantic Coastal Plain” are capitalized. This is because these are formal geologic provinces. The “Fall Line” or “fall zone” is also an important geologic area. The Fall Line is the contact where the hard crystalline rocks of the Piedmont dip under and disappear beneath the sediments of the Coastal Plain. The fall zone is a narrow zone that parallels the Fall Line where rapids and waterfalls are common. The landscape and rock types shown in northern Delaware are classical examples of the larger geologic features that dominate the geology of eastern North America.Item Geochemistry Of The Mafic Rocks, Delaware Piedmont And Adjacent Pennsylvania And Maryland: Confirmation Of Arc Affinity(Newark, DE: Delaware Geological Survey, University of Delaware, 2001) Plank, M.O.; Srogi, L.A.; Schenck, W.S.; Plank, T.A.Geochemical data from Ordovician and Silurian mafic rocks in the Wilmington Complex in Delaware, the James Run Formation in Cecil County, Maryland, and the Wissahickon Formation in Delaware and Pennsylvania were collected in conjunction with preparation of a new geologic map of the Delaware-Pennsylvania Piedmont. Although concentrations of most elements may have been disrupted by metamorphism, the more stable high field strength elements, including the rare earth elements (REE), are consistent within mapped lithodemic units and are compared to modern basaltic magmas from relatively well known tectonomagmatic environments.Item Geology And Hydrology Of The Cockeysville Formation Northern New Castle County, Delaware(Newark, DE: Delaware Geological Survey, University of Delaware, 1995) Woodruff, K.D.; Plank, M.O.; Werkheiser, W.H.The effect of rapid growth in the Hockessin and Pleasant Hill areas in northern Delaware has caused concern about possible declines in ground-water recharge to the underlying Cockeysville Formation. The Cockeysville is a major source of ground water (aquifer) in the Hockessin area from which about 1.5 million gallons of water per day is withdrawn for public water supply, even though it receives recharge over a relatively small area of 1.6 square miles. The Cockeysville in the Pleasant Hill area is currently used as a source at water supply for individual domestic users and one school. Results of ground-water exploration in the Pleasant Hill area suggest that the Cockeysville is capable of yielding several hundreds of gallons per minute to individual wells for water supply. A two-year investigation was undertaken to map the extent of the Cockeysville Formation and address questions of long-term ground-water yields. the sources of recharge, and the effects of additional development on ground-water supplies. Results of various field studies were integrated to determine the basic geologic framework and those elements that particularly affect ground-water supply.Item The Setters Formation In The Pleasant Hill Valley, Delaware: Metamorphism And Structure(Newark, DE: Delaware Geological Survey, University of Delaware, 1997) Plank, M.O.; Schenck, W.S.The Setters Formation, identified on the southeast side of Pleasant Hill valley in well Cb13-16, contains the prograde mineral assemblages (1) microcline, biotite, and sillimanite +/- garnet, and (2) microcline, biotite, sillimanite, and muscovite +/- garnet. These pelitic assemblages allow us to infer peak metamorphic conditions between 620° and 680°C and 4 to 6 kilobars pressure, if PH20/Pfluid is > 0.5. There is some evidence in the drill cuttings to indicate that partial melting accompanied the formation of sillimanite, thus constraining peak temperature to > 640°C.