The Kit Fox Hills: Pleistocene Uplift and Basin Development in Death Valley, California

The Kit Fox Hills (KFH) are the 17-km-long, 4-km-wide, low hills located in northern Death Valley, California. The KFH are composed of poorly indurated, laminar, thin-bedded fine sand to clay beds deposited in distal alluvial fan to playa lake paleoenvironments. These beds are overlain by boulder to sand, poorly to well bedded, boulder to sand beds of medial fan paleoenvironments. Late Pliocene (3.35 – 2.8 Ma) to middle Pleistocene (0.66 Ma Lava Creek B ash bed) tephra beds are intercalated with the deposits. The KFH are adjacent the right-lateral Northern Death Valley fault zone (NDVFZ) with an un-named fault bounding the east side. In the south, (a) the east-side fault offsets (normal) alluvial fan deposits that cap the hills, (b) relief is greater (182 m), (c) active channel profiles are concave up, and (d) isoclinal folds adjacent the NDVFZ are overturned. In contrast, to the north (a) the east-side fault is a series of subparallel, curvilinear, normal faults that offset younger alluvial fans, which are found as terraces within canyons, (b) relief is only 12 m, (c) active channel profiles are convex up, and (d) folds are open. Tephrochronology limits KFH uplift to the Pleistocene (post-0.66 Ma). The variation in KFH structure and geomorphology is consistent with south to north growth of the KFH. Based on proximity, the KFH are interpreted as a possible flower structure formed by the NDVFZ. The NDVFZ is a relatively new element in 8+ Ma years of extension in Death Valley and is similar to basin-cutting faults that develop in highly extended modeling studies and observed in field studies in other extensional basins.