DETERMINING THE TECTONIC HISTORY OF THE MARCELLUS FORMATION THROUGH ANALYSIS OF FRACTURE POPULATIONS
We focused our mapping in the hanging wall of a prominent E-W striking, gently dipping thrust fault, with a dip separation of ~10 meters. This section reveals a complex deformation history in sub-horizontal beds. The fault indicates early shortening in the N-S direction. Sets of small N-S striking thrust faults, along with N-S striking folds, and conjugate sets of wrench faults indicate later E-W shortening. Two other joint sets generally oriented at 020° and 350° abut these wrench faults, indicating a later stage of extension in the E-W direction. There are also large, widely spaced E-W striking fractures that almost all other fractures terminate against. Fracture mineralization is pervasive in the study area, indicating fluid flow is not constrained to one fracture orientation; unmineralized, partially mineralized, and completely filled fractures coexist. This strain history illustrates the changing deformation conditions of the Appalachian Basin and the 3-D fracture network it creates has implication for fracture related fluid flow.