Novaculite

Novaculite flatirons in the Marathon Uplift^[1]

Novaculite is a form of chert or flint found in the Ouachita Mountains of Arkansas and Oklahoma and in the Marathon Uplift of Texas. Novaculite is considered to be highly siliceous sediments and may be a product of the low-grade metamorphism of chert beds. The strata were deposited in the Devonian Period and early Mississippian Subperiod and subjected to uplift and folding during the Ouachita orogeny of the Atokan Epoch (early Pennsylvanian Subperiod). Novaculite is very resistant to erosion and the layers of novaculite stand out as ridges in the Ouachita Mountains.

Novaculite is a form of microcrystalline or cryptocrystalline quartz. The color varies from white to grey-black and the specific gravity shows an increase from 2.2 to 2.5. The very hard dense rock is used as a whetstone; whetstones of this material are described as Arkansas stones. It has been mined since prehistoric times both as material for use as arrow and spear points and as sharpening stones.^[2] Moreover, the upper strata of Arkansas Novaculite, known as tripoli, has found a niche within the coatings, adhesives, sealants and elastomer industry as a performance additive or filler. Tripoli is mined just east of Hot Springs, Arkansas by Malvern Minerals Company.^[3]

The word novaculite is derived from the Latin word novacula, for razor stone.

References

• Folk, R.L., and E.F. McBride, 1976, The Caballos Novaculite revisited Part I: ”origin of novaculite members . Journal of Sedimentary Petrology. 46:659-669
• Folk, R.L., and E.F. McBride, 1978, Origin of the Caballos Novaculite. in S.J. Mazzullo, ed., Tectonics and Paleozoic facies of the Marathon Geosyncline, West Texas: Permian Basin Section, Society for Sedimentary Geology, SEPM, Publication no. 78-17:101-130.
• Frondel, C., 1962, The System of Mineralogy of J. D. and E. S. Dana, v. 3, Silica Minerals: 7th ed., John Wiley and Sons, New York, 334p.
• Lowe, D.R., 1975, Regional Controls on Silica Sedimentation in the Ouachita System. Geological Society of America Bulletin. 86:1123-1127
• Lowe, D.R., 1976, Nonglacial varves in lower member of Arkansas Novaculite (Devonian), Arkansas and Oklahoma. American Association of Petroleum Geologists Bulletin. 60:2103-2116.
• Lowe, D.R., 1977, The Arkansas novaculite: some aspects of its physical sedimentation. in C.G. Stone, and others, eds., Symposium on the geology of the Ouachita Mountains. Arkansas Geological Commission Miscellaneous Publication 13:132-138.
• Lowe, D.R., 1989, Stratigraphy, sedimentology, and depositional setting of pre-orogenic rocks of the Ouachita Mountains, Arkansas and Oklahoma, in R.D. Hatcher, Jr., W.A. Thomas, and G.W. Viele, eds., The Appalachian-Ouachita orogen in the United States. The Geology of North America. F-2:575-590, Geological Society of America, Boulder.
• McBride, E.F., 1989, Stratigraphy and sedimentary history of Pre-Permian Paleozoic rocks of the Marathon uplift, in R.D. Hatcher, Jr., W.A. Thomas, and G.W. Viele, eds., The Appalachian-Ouachita orogen in the United States. The Geology of North America. F-2:603-620, Geological Society of America, Boulder.
• King, P.B., 1937, Geology of the Marathon Region, Texas, United States Geological Survey Professional Paper 187
• Krumbein, W.C. and Sloss, L.L., 1963, Stratigraphy and Sedimentation: 2nd ed., W. H. Freeman and Company, San Francisco, 660p.

External links

• Arkansas Geological Commission: Novaculite
• Olympus, Polarized Light Microscopy Digital Image Gallery: Novaculite
• Arkansas Archeological Survey: Arkansas Novaculite: A Virtual Comparative Collection