Oklahoma Unconformity Interpreted

The angular unconformity has a lot of relief, paleotopography on it, even at this scale. Coupled with the coarse grained and massive overlying conglomerate (which is more likely a fanglomerate) the traits here suggest that these conglomerates are syn-tectonic and being shed from a tectonically uplifted source area, possibly along a nearby fault scarp. The intense fracture set in underlying limestones (lower right part) can easily be misinterpreted as bedding. Some of these fractures may have movement along them and be small scale faults that formed by reactivating early joints. Note they are roughly perpendicular to bedding in the older, underlying sequence, a common orientation for joint sets. The late fault may take a more experienced eye to see. The descriptor 'late' is used because it cuts the overlying conglomerate, and therefore must occur late in the sequence of structural events recorded in this outcrop. Overall this is deformation associated with Quachita orogeny, but as a tectonic feature that extended more into the interior of the continent.

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