Paleomagnetism of the Cambrian rocks of the Great Valley of east central Pennsylvania: Fold test constraints on the age of magnetization

1984 ◽  
pp. 120-130 ◽  
Author(s):  
Richard J. Stead ◽  
Kenneth P. Kodama
Keyword(s):  
East Central ◽  
Central Pennsylvania ◽  
Great Valley

scholarly journals Effects of Stump Diameter on Sprout Number and Size for Three Oak Species in a Pennsylvania Clearcut

2009 ◽  
Vol 26 (3) ◽  
pp. 122-125 ◽  
Author(s):  
Benjamin A. Sands ◽  
Marc D. Abrams
Keyword(s):  
Maximum Height ◽  
White Oak ◽  
Diameter Class ◽  
Quercus Velutina ◽  
East Central ◽  
Central Pennsylvania ◽  
The Mean ◽  
Black Oak ◽  
Stump Sprouts ◽  
Stump Diameter

Abstract In a 2004 clearcut of a former even-aged oak (Quercus) forest, we examined the number and maximum height of stump sprouts for three oak species in east-central Pennsylvania. The greatest number of sprouts was produced by black oak (Quercus velutina) and chestnut oak (Q.montana) as compared with white oak (Q. alba). Logistic regression showed that diameter of stumps was a significant factor in determining the probability of sprouting for black oak, and an inverse relationship between stump diameter and the number of sprouts per stump was foundfor all three species. The number of white oak sprouts peaked in the 10‐20-cm diameter class and declined on larger stumps. The number of black oak sprouts peaked in the 20‐50-cm classes, and trees in the 70‐80-cm class produced the fewest sprouts. The mean annual growthof the tallest sprout on each stump was greater for black oak and chestnut oak than white oak.

Comparison of recharge estimates at a small watershed in east-central Pennsylvania, USA

2008 ◽  
Vol 17 (2) ◽  
pp. 287-298 ◽  
Author(s):  
Dennis W. Risser ◽  
William J. Gburek ◽  
Gordon J. Folmar
Keyword(s):  
Small Watershed ◽  
East Central ◽  
Central Pennsylvania

Wind-Transverse Corrugations in Pleistocene Periglacial Landscapes of Central Pennsylvania

1998 ◽  
Vol 49 (2) ◽  
pp. 149-156 ◽  
Author(s):  
Ben Marsh
Keyword(s):  
Wind Direction ◽  
Wide Distribution ◽  
Early Holocene ◽  
Landscape Position ◽  
Stream Channels ◽  
Ground Ice ◽  
East Central ◽  
Dune Field ◽  
Local Slope ◽  
Central Pennsylvania

Periglacial conditions beyond the Wisconsin glacial limit produced wind-transverse corrugations in east-central Pennsylvania. The corrugations are low, linear ridges typically several hundred meters long, 10–30 m wide, and 3–8 m above the local slope. They are composed of matrix-supported diamictons. Depending upon landscape position, the corrugations form welts, step and risers, or ground-ice-scar ramparts. The average direction normal to the corrugations is clustered at 118°/298°, similar to the late Wisconsin or early Holocene wind direction of 284° measured from a nearby fossil dune field. But the corrugations were neither eroded nor deposited by wind. Rather, they record nivation beside snow that accumulated in wind-transverse patterns. Their wide distribution implies that the region was treeless during the late Wisconsin maximum. Present discontinuities in these and other periglacial features suggest wasting of ice-rich fill in upland valleys, with consequent widening of stream channels and fan growth, at the end of periglacial time.

scholarly journals Agricultural phosphorus and water quality: sources, transport and management

1998 ◽  
Vol 7 (2) ◽  
pp. 297-314 ◽  
Author(s):  
Andrew Sharpley ◽  
William Gburek ◽  
Louise Heathwaite
Keyword(s):  
Water Quality ◽  
Land Use ◽  
East Central ◽  
Soil P ◽  
Agricultural Catchments ◽  
Central Pennsylvania ◽  
Chemical Factors ◽  
Mixed Land Use ◽  
Extractable Soil ◽  
Freshwater Eutrophication

Freshwater eutrophication is usually controlled by inputs of phosphorus (P). To identify critical sources of P export from agricultural catchments we investigated hydrological and chemical factors controlling P export from a mixed land use (30% wooded, 50% cultivated, 20% pasture) 39.5-ha catchment in east-central Pennsylvania, USA. Mehlich-3 extractable soil P, determined on a 30-m grid over the catchment, ranged from 7 to 788 mg kg-1. Generally, soils in wooded areas had low Mehlich-3P (

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