Metamorphic Rock Structure Reflected in Soil Profile
December 15, 2012
Photographer: Russell Losco; Russell's Web site
Summary Author: Russell Losco
Pictured above is a soil profile located in southeastern Pennsylvania, not far from Kennett Square. This is a residual soil of the Glenelg series, a freely drained and moderately deep soil derived from high-grade metamorphic rock of the Wissahickon Formation. The Wissahickon is Paleozoic-aged rock, probably deposited as Cambrian to Pre-Cambrian sediments and then metamorphosed through the Ordovician to Devonian periods. Note the curved and stretched layers evident in the lower left quadrant of the photo. Interestingly, they exhibit the same folds and foliations evident in the parent bedrock (not seen). The ovoid white structure in the lower right quadrant is a pocket of feldspar, degrading into kaolinite. Photo taken on May 4, 2010 while conducting soil testing on the site to support proposed land development.
Photo details: Camera Maker: General Imaging Co.; Camera Model: A830; Focal Length: 6.1mm; Aperture: f/2.8; Exposure Time: 0.033 s (1/30); ISO equiv: 180; Exposure Bias: none; Metering Mode: Center Weight; Exposure: program (Auto); White Balance: Auto; Flash Fired: Yes (Auto, return light detected); Color Space: sRGB; Software: Version Ver 1.05.