Abstract The anomalously low‐relief topography of the eastern Snake River Plain (ESRP) was produced by southwest Miocene migration of North America over the Yellowstone mantle plume. Multiple fault‐related mountain ranges abruptly terminate at the plain margins, and it has been posited that migration over the plume drove east‐west extension of the ESRP and adjacent Basin and Range, with the extensional footwall ranges that were continuous across the ESRP being “erased” by cooling‐related crustal subsidence. However, direct evidence that these extensional systems were once continuous across the ESRP has remained limited, and questions remain regarding the process of “erasing” topography across the ESRP, particularly adjacent to the modern Yellowstone caldera. Analysis of recently acquired LiDAR data in the Yellowstone region reveals a dominant north‐south trending extensional zone that spans the Yellowstone caldera and aligns with the active Teton and East Gallatin normal faults. Displacement analysis of these structures, when integrated with geophysical and geodetic data, indicates a kinematic linkage between the Teton and East Gallatin systems and provides critical evidence that these active faults were originally continuous across the hotspot track. Unlike other ranges that terminate against the ESRP, the removal of paleo‐Teton and East Gallatin footwall topography cannot be explained by crustal subsidence due to cooling, given the elevated heat flow in the vicinity of Yellowstone. We propose that the collapse of these paleo‐ranges into the calderas following the Huckleberry Ridge (∼2.06 Ma) and Lava Creek (∼0.6 Ma) eruptions can, at least in part, explain the removal of footwall topography.
Swallom et al. (Sun,) studied this question.