14 Paleontologic Advances in the Cordilleran Region

Thursday, 18 May 2023
8:00 AM - 12:00 PM
Whitney Peak Ballroom 3

FINISHING THE PERMIAN GEOLOGICAL TIME SCALE BY DEFINING FREELY ACCESSIBLE STAGE BOUNDARIES IN NEVADA

Paper number: 14-13
Program: Theme Sessions
Time: 11:40 AM – 12:00 PM

Authors

Abstract

The geologic time scale provides a temporal ruler against which the events of geologic history are recorded. It is the basis for assessing time-dependent processes such as the formation of ore deposits, for documenting the timing of extinction and the recovery from extinction events, for comparing the timing and mechanisms of today’s climate change versus those locked in the rock record, and much more. However, the development of the time scale is still a work in progress. The International Commission on Stratigraphy has been working for decades to standardize the International time scale. The way this is done is to select a point within a well-studied stratigraphic section where a “golden spike” is used to mark the stage boundaries of the various systems. In Nevada, two stratigraphic sections are being considered as standards for the Permian. One is in Carlin Canyon, stratigraphically above a spectacular angular unconformity. Outcrops near this site are being considered as the standard auxiliary boundary stratotype (SABS) for the 12 million years associated with the upper Asselian to upper Artinskian. Here the Strathearn and Buckskin Mountain formations contain typical late Paleozoic fusulinids, and invertebrate fossils like crinoids, brachiopods and bryozoans, and small teeth of an eel-like animal, the conodont. The record of conodont evolution at this site matches the record at sections in the Ural Mountains of Russia where the base-Sakmarian and base-Artinskian Global Stratotype Sections and Points (GSSP) reside. However, scientific sanctions against Russia for their invasion of Ukraine and the lack of free access to existing sections mean that no further GSSPs are allowed in Russia, for the foreseeable future. The result of this decision by the International Union of Geological Sciences means that the best section to define the base Kungurian Stage outside Russia is located in northeastern Nevada at the Rockland section in the Pequop Mountains, south of Wells. The Subcommission on Permian Stratigraphy is preparing a proposal to define a point in the Rockland section as the base-Kungurian GSSP. This talk will discuss how GSSPs are developed, highlight what is needed to finalize a GSSP, and seeks the advice and support of the local community to secure and protect these Geological Time Scale markers in the state of Nevada.

Geological Society of America Abstracts with Programs. Vol. 55, No. 4

doi: 10.1130/abs/2023CD-387167

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