A discussion of the depositional environment and silica sources of the novaculite in Broken Bow, Oklahoma
- Washington Univ., St. Louis, MO (United States). Earth and Planetary Sciences Dept.
There has been considerable research and speculation concerning the depositional environment for the silica sources of the Arkansas Novaculite in the Ouachita Mountains. Arkansas Novaculite conformably overlies Missouri Mountain Shale and underlies the Mississippian Stanley Shale group. Structural evidence in the Ouachita's supports a continent-continent collision and/or island arc subduction involving the continental margin of North America during Late Mississippian, after the novaculite sequence (Thomas, 1989, Appalachian-Ouachita orogen beneath the eastern gulf coastal plain, DNAG F-2). When considering the amount of silica required for deposition of massive and relatively pure silica-rich novaculite, the following were taken into account: (1) the source of the silica, (2) what environment will support silica-based marine life, and (3) what environmental conditions would account for thick, clean silica beds. Great quantities of silica most likely came from several sources. Structural evidence supports sources from the suspect Ouachita wedge and volcanic ash. Abundant fossil evidence suggests that a large portion of the silica source can be attributed to marine life such as radiolaria and sponge spicules. Though the role of metamorphic activity could be key in the formation of these novaculites, correlation of structural and sedimentary depositional features, and fossil evidence overwhelmingly indicate a marine environment for the silica source. The predisposition of radiolaria for an open ocean environment, the conodonts' restricted ranges, the preference of most siliceous sponges for a deep ocean environment, and the lack of stratigraphic evidence pointing to a shallowing of the seas, suggest that the Arkansas-Oklahoma novaculites from deep-marine radiolaria deposits with additional deposition from sedimentary sources.
- OSTI ID:
- 5018829
- Report Number(s):
- CONF-9303210-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:3; Conference: 27. annual Geological Society of America (GSA) North-Central Section meeting, Rolla, MO (United States), 29-30 Mar 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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