A LOW TEMPERATURE THERMOCHRONOLOGIC INVESTIGATION OF THE NORTHERNMOST TETON RANGE, WY: TESTING THE PALEO-TETON COLLAPSE HYPOTHESIS

Multiple mountain ranges in the northern Basin and Range abruptly terminate against either the low relief Yellowstone-Snake River Plain or the present-day Yellowstone caldera. The genesis of this abrupt topographic transition remains enigmatically unresolved. The Teton Range, which formed in the footwall of the Teton fault, extends ~70 km south of the Yellowstone caldera, but it has been hypothesized to have extended significantly further north across Yellowstone prior to the <2.1 Ma Huckleberry Ridge and subsequent caldera forming eruptions. A previous thermochronologic study demonstrated that motion on the Teton normal fault likely exhumed footwall rocks of the Teton Range from a depth of > 3 km. When integrated with flexural-kinematic modeling, this yields total maximum displacement estimates of >11 km, which in turn yields a fault length much greater (than the present-day observed length of 70 km, based on length-displacement scaling relationships. To further test this hypothesis that the Teton Range extended significantly further north into Yellowstone, a new AHe transect was collected at Ranger Peak in the northermost extent of the range. This transect allows us to model the footwall cooling driven by displacement on the Teton fault, and thus assess whether or not the relatively large displacement at Mount Moran continues to the north.