We've Moved!
Visit SDSU’s new digital collections website at https://digitalcollections.sdsu.edu
Description
In the Inyo Mountains, California, there are good exposures of Cordilleran-type Middle Paleozoic strata which formed in the western part of the Great Basin. Based upon conodont and graptolite studies Silurian rocks are: the upper two units of the Ely Springs Dolomite; and the lower 250 (?) m of the southern Vaughn Gulch Limestone. Early to Middle Devonian rocks are: the upper 200 m of the southern Vaughn Gulch Limestone; the northern Vaughn Gulch Limestone; and the Sunday Canyon Formation. Therefore, the southern Vaughn Gulch Limestone conformably overlies the Ely Springs Dolomite, whereas the northern Vaughn Gulch Limestone and Sunday Canyon Formation unconformably overlie the Ely Springs Dolomite. Units 2 and 3 of the Ely Springs Dolomite are massive, light-gray dolostones and medium-gray cherty dolostones respectively. The southern Vaughn Gulch Limestone consists of: authochthonous thin-bedded to massive limestones and silty limestones; allodapic limestones; and cherty limestones. Northern exposures consist of dolomitic siltstones; authochthonous thin- to medium-bedded limestones; and allodapic limestones. The Sunday Canyon Formation consists of authochthonous laminated to medium-bedded limestones; allodapic limestones; and calcareous siltstones. All three units of the Ely Springs Dolomite formed on a broad shallow shelf. During and/or after deposition of unit 3, there was uplift in the northern part of the region resulting in the dissolution and erosion of the formation from Early Silurian to Early Devonian time. Deposition remained continuous in the southern Vaughn Gulch Limestone which formed in a basin that was affected by slumping from the topographic high in the north and by proximal turbidites and debris flows from carbonate skeletal buildups in the south. By Early Devonian time uplift had ceased and deposition resumed in the north as represented by the northern Vaughn Gulch Limestone and Sunday Canyon Formation. The northern Vaughn Gulch Limestone accumulated in a distal fore-reef environment with autochthonous clastic sedimentation interrupted by allodapic limestones emplaced as turbidites and conglomerates which were derived from the carbonate skeletal buildups in the south. The Sunday Canyon Formation formed in a restricted carbonate basin environment also affected by distal turbidites from the south. In late Middle Devonian time there was submarine channeling of the Vaughn Gulch and Sunday Canyon Formations; followed by the deposition of the cherts and shales of the Squares Tunnel formation.
