Quinn River Formation, Black Rock terrane, northern Nevada: New Permian and Triassic radiolarian data

Conference · Thu Apr 01 00:00:00 EST 1993 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:5437165

Blome, C D ^[1]; Reed, K M ^[2]

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1. Geological Survey, Denver, CO (United States). Federal Center
2. Washington DNR/DGER, Olympia, WA (United States)

The Quinn River Formation near Quinn River Crossing contains in ascending order: a basal tuff overlain by limestone and ferruginous dolomite, 25 m of dark interbedded radiolarian-bearing chert and argillite, an unconformably overlying 22 m of siltstone and carbonaceous shale, and 110 m of partly volcaniclastic rocks that include siltstone, shale, and minor sandstone and radiolarian-bearing argillite. Previous workers reported the occurrence of early Guadalupian radiolarians and the late Wordian conodonts Mesogondolella phosphoriensis and M. aff. M. prolongata from near the top of the overlying chert. Re-collection of the chert (35 samples) shows that all but the uppermost samples contain radiolarians characteristic of Kozur and Mostler's Capitanian (late Guadalupian) Follicucullus charveti-Imotoella triangularis Assemblage Zone. Similar faunas have been described from the Dekkas Formation in the Klamath Mountains and in cherts from the Grindstone terrane of east-central Oregon. Even younger radiolarian forms belonging to Neoalbaillella were found near the top of the chert section. Occurrence of Wordian conodonts at the same stratigraphic level as Capitanian or younger radiolarians suggests that the conodonts are reworked. In the overlying volcaniclastic section, previous workers reported Early Triassic radiolarians from the lower part, Middle Triassic (Ladinian) ammonites from the middle part, and an early Anisian ammonite and Middle Triassic conodonts and radiolarians from near the top. However, argillite approximately 25 m below the top of the section yielded a Late Triassic (Carnian) radiolarian fauna that includes taxa belonging to Castrum, Corum, Poulpus, Pseudostylosphaera, Triassocampe, and Xipha. This fauna is similar to that from the Fields Creek Fm in east-central Oregon. These anomalies suggest either that the previous collections from this part of the section are misdated or that the upper part of the volcaniclastic section is structurally disrupted.

• OSTI ID: 5437165
• Report Number(s): CONF-9305259-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 25:5; Conference: 89. annual meeting of the Cordilleran Section and the 46th annual meeting of the Rocky Mountain Section of the Geological Society of America (GSA), Reno, NV (United States), 19-21 May 1993; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
GEOLOGIC FORMATIONS
AGE ESTIMATION
PALEONTOLOGY
NEVADA
ARGILLITE
CARBONATE ROCKS
CHERT
FORAMINIFERA
PERMIAN PERIOD
TRIASSIC PERIOD
VOLCANIC ROCKS
ANIMALS
DEVELOPED COUNTRIES
GEOLOGIC AGES
IGNEOUS ROCKS
INVERTEBRATES
MESOZOIC ERA
MICROORGANISMS
NORTH AMERICA
PALEOZOIC ERA
PROTOZOA
ROCKS
SARCODINA
SEDIMENTARY ROCKS
SHALES
USA
580000* - Geosciences