ABSTRACT: Chitinozoan Zones of the Western United States (Great Basin), and Their Comparison with Those of the Canning Basin, Western Australia
T. J. Hutter
Within the Basin and Ranges of the Great basin of the western United States, Ordovician chitinozoans have been recovered in two major lithic facies; the "western" eugeosynclinal facies and the "eastern" miogeosynclinal facies. Chitinozoans recovered from these facies range in age from Arenig to Ashgill. Extensive collections from this area make possible the establishment of chitinozoan faunal interval zones from the Ordovician. These zones are compared with those of other investigators for the Canning basin of Western Australia. Selected species of biostratigraphic value include, in chronostratigraphic order, Lagenochitina ovoidea Benoit & Taugourdeau 1961, Conochitina langei Combaz & Peniguel 1972, Conochitina poumoti Combaz & Peniguel, Desmochitina cf. nodos Eisenack 1931, Conochitina maclartii Combaz & Peniguel 1972, Conochitina robusta Eisenack 1959, Angochitina capillata Eisenack 1937, Sphaerochitina lepta Jenkins 1970 and Ancyrochitina merga Jenkins 1970. In many cases these zones can be divided into additional subzones using chitinozoans and acritarchs. In all cases, these chitinozoan faunal zones are contrasted with established "American" graptolite zones, as well as correlated with British standard graptolite zones. The composition of these faunas of the Western United States Great basin and Western Australia Canning basin is similar
to that from the Marathon region of west Texas, and the Basin Ranges of Arizona and New Mexico.
AAPG Search and Discovery Article #90097©1990 Fifth Circum-Pacific Energy and Mineral Resources Conference, Honolulu, Hawaii, July 29-August 3, 1990