THE STANSBURY UPLIFT: NORTH-SOUTH BOUNDARY OF PROVENANCE FOR THE LATE DEVONIAN CONTINENTAL MARGIN, WESTERN LAURENTIA

The Late Devonian Stansbury Uplift of north-central Utah may be linked to the Tooele Arch, a part of the inverted Uinta Mountain Group basin. Aside from it being a distal feature of the Antler orogen, no other regional tectonic features are known that would cause the Stansbury Uplift. Furthermore, the Stansbury Uplift is the only known inboard uplift of this magnitude, which we suggest is attributed to Antler tectonic loads.

Detrital zircons record several provenance areas for Devonian-Mississippian sandstones in the western North American passive margin, inboard of the Antler basins. A “northern” signature of central and southeastern Idaho is characterized by grains >1800 Ma. In Devonian Three Forks and Beirdneau sandstones, grains are proximally sourced from uplifted Ordovician Swan Peak Formation and ultimately sourced from the Canadian Peace River Arch. The “southern” signature is identified by Grenville (1.3-1.0 Ga), and Yavapai-Mazatzal (1.8-1.6 Ga), zircon populations and is found in the Guilmette Formation of central and southern Nevada. The boundary between these two signatures is the Stansbury Uplift, a late Devonian uplift in north-central Utah along the recurrently active Paleozoic Tooele Arch. The Stansbury Formation, shed from this uplift, contains a strong population of >1800 Ma zircons, but includes a subordinate population of 1470 to 1500 Ma zircons derived from mid-continent granites. Delineating the provenance of middle Paleozoic sands might constrain the extent to which the Stansbury Uplift developed along the Tooele Arch.