129-7 A Labyrinth of Lines: Exploring Potential Stress Field Sources of Significant Jointing in an Abandoned Limestone Quarry in Southwest Ohio (Oakes Quarry Park)

Abstract:

Joints are in-situ cracks in rock that indicate stresses that have pushed the rock beyond its plastic, elastic, or brittle limits. Pairs of oblique lines indicating stress fields can often be traced back to local tectonics, isostatic rebound, or any kind of localized extension event. One of the most expressive features in the structural geology of Southwest Ohio is the Cincinnati Arch. Primarily due to the first order structures created by the major plate convergence of the Alleghenian orogeny, the uplift of this horseshoe-shaped dome is suspected to have begun first in the Cambrian and continued through the Silurian. On the fringes of the Cincinnati Arch, distinct joints split the surface of the exposed basal Silurian Brassfield Limestone within Oakes Quarry Park, 190 acres of abandoned quarry undergoing wetland restoration. The Brassfield Limestone consists mostly of carbonate rocks with interbedded shale and is believed to be an onlap feature of the uppermost Ordovician. The prominence and great number of the clearly defined joints littering the former floor of the quarry sparks immediate curiosity about their stress source. The local stress field of the Cincinnati Arch and the Alleghenian orogeny, rebound after removal of overburden, thermal expansion, and high energy blasting all present themselves as potential stress sources. Five hundred and thirty-five (535)  joints, dispersed over three distinct exposures that make up 67 acres of the Oakes Quarry floor, were individually traced using GPS, measuring their strikes and lengths. The collected strike orientations indicated that most of the strikes fall into two primary ranges. The most common range of strikes gave an average of 265 ±8.4 degrees. These strikes were generally much longer on average than those of the second most common orientation which was at approximately 335±8.3 degrees and characteristically shorter and less defined. This research is an investigation of the source that created these joints in Oakes Quarry, utilizing the stress field indicated by the analytics of the strike orientations and joint lengths.

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.