HIGH-RESOLUTION CHEMOSTRATIGRAPHIC CORRELATION WITHIN THE MIDDLE CAMBRIAN WHEELER FORMATION

The Middle Cambrian Wheeler Formation of western Utah contains well preserved fossils and provides a record of the diverse depositional environments encountered along a shelf-to-basin transect within the House Range Embayment. Establishment of the passive margin along western North America was coincident with the rapid evolution of marine faunas and proliferation of early metazoans. The lack of understanding about this radiation and why it was selectively preserved in certain Cambrian formations, such as the Wheeler, stems partially from our lack of knowledge about Cambrian oceans and the effect climate and tectonics had on these environments.

The depositional environments of the Wheeler Formation vary laterally, spanning shelf, slope, and basin environments. The shelf deposits of the Drum Mountains (300 m thick) were previously interpreted as representing deposition during a 3^rd order eustatic regression with several higher order cycles superimposed upon it. The basinal deposits of the House Range (150 m thick) do not record the higher order cyclicity, making cyclostratigraphic correlation difficult. Although there are biostratigraphic markers within both sections, the changes in sea level that drove facies migration occurred at temporal scales that are not resolvable by biostratigraphy. Therefore, chemostratigraphy offers the potential for high-resolution correlation across these diverse environments. Preliminary d¹³C_carb data from the Drum Mountains show vertical variability throughout and a shift of -2‰ (PDB) in the upper portion of the section, these values may correlate with similar shifts in d¹³C_carb from other Cambrian sections in the Bolaspidella zone. If d¹³C_carb values in both the Drum Mountain and House Range sections are primary, a high-resolution intrabasinal correlation will be possible. This intrabasinal correlation will allow us to better understand the lateral facies associations, evaluate controls on cycle development, and document the paleoecologic and taphonomic changes that occurred during deposition of the Wheeler Formation.