CHANGES IN SEDIMENT CHARACTERISTICS WITH DEPTH AT THE RONALD R. RHEIN ENVIRONMENTAL STUDY AREA

Changes in sediment characteristics with depth were studied at the Ronald R. Rhein Environmental Study Area of Kutztown University of Pennsylvania, Kutztown, PA. The study area contains a small second order stream with well-defined floodplains. Previous studies focused on sediment variability with depth, and found clay and gravel layers below the topsoil. We aimed to provide more detailed information on grain size and sediment contents by using aluminum cores to extract an accurate stratigraphic column.

We collected five push core samples using aluminum pipes with a diameter of 7.62 centimeters along a 12 meter transect. The transect began with a core in the creek channel and transitioned onto the floodplain in 3 meter increments. Core 1 reached bedrock at 155 centimeters with a maximum depth of 164 centimeters. Core 2 followed a similar trend reaching bedrock at approximately 124 centimeters with a maximum depth of 137.5 centimeters. Core 3 reached a maximum depth of 80 centimeters, this layer contained gravel and pebbles. Cores 4 and 5 reached a maximum depth of 59 centimeters, both containing consolidated clay at depth. All of the cores were split, and detailed lithological descriptions were gathered. The cores were connected to develop a detailed subsurface cross section.

In each core, the grain size average ranges from -6 Φ to approximately 11 Φ. This is a significant range in grain size for the small field area. Grain size in the cores generally fines upwards. According to previous studies bedrock would be found roughly 5 meters down, our data would suggest it is closer to 1 meter. Phylite schist (bedrock) was recovered at the bottom of the section, fining upwards to gravel, silty mud, consolidated clay, and lastly topsoil. There were several intrusions of quartz pebbles throughout cores 1 and 2, along with vein quartz. Portions of the organic layers (35-78 centimeters) recovered in cores 3, 4, and 5 contained iron oxidized pebbles. The variations in grain size and presence of buried organic layers suggest that the depositional environment has changed over time. This is possibly associated with the transition from glacial to interglacial climate or is a result of changes in available sediment as European colonists began farming and mobilized significant volumes of fine sediment to bury pre-existing stable floodplains.