EVALUATION OF THE SYNDEPOSITIONAL TECTONISM HYPOTHESIS FOR THE FORMATION OF THE EDIACARAN JOHNNIE INCISIONS IN EASTERN CALIFORNIA USING STRUCTURAL RESTORATION ANALYSES

The influence of glacial eustasy and tectonics on the formation of the Ediacaran (635-541 Ma) Johnnie incisions in the Nopah Range, eastern California remains unresolved. The origin of the Johnnie Fm. incisions is important because the incisions broadly coincide with the most negative carbon-13 isotope anomaly in Earth history, the Shuram anomaly, as well as with the emergence of the Ediacaran biota. In order to test the potential influence of syndepositional normal faulting on the formation of the Johnnie incisions, we performed structural restorations using StructureSolver to restore mapped surfaces and cross-section horizons. These restorations restore on four different stratigraphic surfaces to evaluate the following questions. 1) Do normal faults that displace the Johnnie oolite and Johnnie incision surface always displace the Stirling Quartzite? 2) Are the beds of Johnnie oolite in the southeast Nopah Range structurally or depositionally repeated? 3) Was the erosional relief of the Johnnie incisions locally enhanced by syndepositional deformation in the southeast Nopah Range? Understanding the origin of the Johnnie incisions (glacial eustasy vs. syndepositional extensional faulting related to continental rifting) will further elucidate the co-evolution of the incisions, life, and climate.