4:37 p.m., Oct. 31, 2012--The Office of the State Climatologist and the Delaware Geological Survey (DGS), both based at the University of Delaware, provided the Delaware Emergency Management Agency (DEMA) and the National Weather Service with weather, coastal flooding and stream flooding information for Delaware during Hurricane Sandy.
William "Sandy" Schenck lead a field trip through the Delaware Piedmont for the A.I. duPont High School Earth Science Class. The trip made use of the Wilmington-Western Railroad and everyone rode the railroad's "Doodle Bug." Activities included up close examinations of rock and mineral features and even "Panning for Garnets" at Brandywine Springs Park.
The Red Clay Creek has flowed through the rolling hills of northern Delaware for many thousands of years, cutting a deep valley into the old deformed rocks of the Appalachian Piedmont. The Red Clay valley contains many of the common rocks found throughout the Delaware Piedmont.
USGS 01480015 RED CLAY CREEK NEAR STANTON, DE
USGS 01480000 RED CLAY CREEK AT WOODDALE, DE
Along the edge of the Red Clay Creek exists a large outcrop that extends out into the stream. This rock is part of the Wissahickon Formation, with pelitic facies, ½" elongated sillimanite nodules, and disharmonic folds. The compositional layering of this rock is 1/8 – ½" of biotite rich layers alternated with fine-grained psammitic layers (not quartz-feldspar layers). Some of these layers are sheared (shear zones). The sillimanite nodules, pegmatite pods, and shear zones in this rock are all parallel to fold axes. The axial plane of these folds is 20 degrees east of north, plunges 42 degrees northeast, and dips 90 degrees. Within this large outcrop are several 2-3' layers of “rock that rings” (when hit) and are folded with petitic gneiss. This pelitic gneiss shows more intense folding while the rest of the rock is gently folded. The “rock that rings” is also peppered with small lavender garnets.
This report describes the geological and lithological conditions in the Newark area, and the occurrence, quantity, and quality of the available ground-water supply. Newark is located on the Fall Line, the boundary between the rolling hills of the Piedmont on the north and the gentle slopes of the Coastal Plain on the south.
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.
William S. Schenck, a scientist with the Delaware Geological Survey, has been taking students from A.I. duPont High School on Wilmington & Western Railroad tours, observing rock outcrop locations along the way.