Integrated Biostratigraphic Standard of Reference for the Lower Devonian (Lochkovian) Using Conodonts and Graptolite Lineages

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The research will continue studies that seek to establish an integrated biostratigraphic standard of reference for Lower Devonian faunas of western North America Cordillera based on quantitative studies of variation within conodont and graptolite lineages and will add ostracode faunas to the synthesis. An integrated and detailed standard of reference is necessary to an understanding of paleobiological problems of biogeography, biofacies and patterns of evolution. It is also required to solve stratigraphic and structural problems requiring a high degree of resolution. Such studies are rare in the literature because the concurrence of the factors necessary for success is rarely encountered. Previous quantitative studies of the lower Lower Devonian in central Nevada have demonstrated the utility of conducting statistical studies of conodont lineages for this purpose. By-products of these studies indicate that a number of additional important Lower Devonian conodont lineages are present entirely or in part in several known sections or extensions of them. These sections are located in the Toquima Range, the Simpson Park Range, the Monitor Range and the Roberts Mountains and have formed the primary data base for what is presently known of conodont and graptolite biostratigraphy of this part of the column in the region. Study of several lineages has shown the enhancement of correlation that can be attained and the utility of such studies in attaining a stable classification. Both are ingredients necessary to a detailed and stable biostratigraphic standard of reference.