Neotectonic joints

Neotectonic joint systems are the most recent joint systems to form within a region subject to uplift and erosion. An inventory of neotectonic joint attributes was compiled from observations in case-study terrains containing flat-lying sedimentary sequences in the platform covers of cratons: the Appalachian Plateau, southeast England-northeast France, the Arabian platform, and the Ebro basin in Spain. Neotectonic joint systems are simple, generally consisting of sets of vertical extension fractures or less commonly steep conjugate fractures striking parallel to, or symmetrically about, the extension fractures. Shallow neotectonic joints propagate within the upper 0.5 km of the crust where effective σ ₃ is both tensile and horizontal and σ ₁ - σ ₃ is small. These shallow joint systems generally form within the upper 0.5 km of the crust because unloading as a result of denudation and lateral relief consequent on uplift are prerequisites for their propagation. These structures are of potential value for tracking the contemporary stress field in regions where in situ measurements are not available. -from Authors