Master of Science, University of Akron, 2023, Geology
Rocks develop cracks (joints) to relieve internal stresses as they are depressurized. Joints increase the permeability in rocks, which affects fluid and contaminant flow in the formation. There are three possible causes of joint formation in Northeastern Ohio: tectonics, glaciation, and valley relief. The thoroughly jointed formations exposed in NE Ohio are part of the Appalachian Plateau which has experienced unloading stresses due to the Alleghanian Orogeny (315-270 mya), a more recent series of glaciation events in the Pleistocene (700,000-14,000 years ago) and valley formation by erosion. I measured joint orientations in formations exposed in Northeastern Ohio that were deposited before and during the Alleghanian Orogeny to determine if their orientations reflect stresses during the Alleghanian Orogeny, the Pleistocene ice age, or valley unloading processes. Joint spacing was also measured to determine if a relationship exists between lithology and the joint spacing.
I measured joints in the Olmsted siltstone bed of the Ohio Shale (n=131), Cleveland Member of Ohio Shale (n=131), Bedford Shale (n=209), Berea Sandstone (n=137), Orangeville Shale Member (n=27), Sharpsville Sandstone Member (n=203), and the Meadville Shale Member (n=203). I also analyzed measurements of joint orientations in coal seams, the Ohio Shale, the Black Hand Sandstone Member and Sharon Sandstone from previous studies by Ver Steeg (1942), Miller (1996), Filiano (2014), Ritter
(2016), and Rieman (2017). The data suggests that the joints in all formations were predominantly formed due to tectonics during the main stage of the Alleghanian Orogeny based on the orientation of the primary joint set, which was oriented parallel to maximum compression direction during this event.
Committee: Caleb Holyoke III (Advisor); Molly Witter-Shelleman (Committee Member); Ira Sasowsky (Committee Member)
Subjects: Geology