Abstract
Irregularly shaped blackened limestone pebbles mixed with similar but unblackened material at unconformities have long presented a mystery to geologists examining Tertiary and Holocene limestones in the Caribbean. How can irregularly shaped limestone pebbles showing no signs of lateral transport be mixed together, especially when a distant or underlying source is invariably absent?
The blackened pebbles generally are composed of soilstone crust, lightly lithified grainstone, or mul- ticomponent limestones, and may occur at subaerial unconformities in marine or subaerial (eolian) limestones. The most common examples occur as multicolored breccias in karst potholes, which are abundant throughout the Caribbean.
We propose that selective blackening is caused by “instantaneous” forest fire heating. Simple experiments showed that thorough blackening can occur in one-half hour at temperatures between 400° and 500° C. Heating experiments showed that only those limestones that are commonly black in nature blackened when heated to temperatures similar to those of forest fires. Blackening, restricted mainly to in-dividual sand-size skeletal grains, also occurs under subtidal conditions, and the product of this process should not be confused with fire-blackened limestone pebbles. Correct identification can be useful for distinguishing between submarine diastems and unconformities and subaerial unconformities in ancient limestones.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Barthel, K.W., 1974, Black pebbles, fossil and Recent, on and near coral islands: Proceedings, Second International Coral Reef Symposium, v. 2, Great Barrier Reef Committee, Brisbane, p. 395–399.
Beach, D.K., and Ginsburg, R.N., 1980, Facies succession of Pliocene—Pleistocene carbonates, northwestern Great Bahama Bank: American Association of Petroleum Geologists Bulletin, v. 64, no. 10, p. 1634–1642.
Bush, J., 1958, The foraminifera and sediments of Biscayne Bay, Florida, and their geology: Unpubl. Ph.D. dissertation, University of Wisconsin, Madison, WI, 127 p.
Fischer, A.G., 1961, Stratigraphic record of transgressing seas in light of sedimentation on Atlantic Coast of New Jersey: American Association of Petroleum Geologists Bulletin, v. 45, p. 1713–1721.
Ginsburg, R.N., 1957, Early diagenesis and lithifi- cation of shallow-water carbonate sediments in southern Florida, in LeBlanc, R.J., and Breeding, J.G., eds., Regional aspects of carbonate deposition: Society of Economic Paleontologists and MineralogistsSpecial Publication 5, 178 p.
Houbolt, J.J.H.C., 1957, Surface sediments of the Persian Gulf near the Qatar Peninsula: Unpubl. Ph.D. dissertation, University of Utrecht, the Hague, Mouton and Company, 113 p.
Kornicker, L.S., 1958, Bahamian limestone crusts: Transactions, Gulf Coast Association of Geological Societies, v. 8, p. 167–170.
Macintyre, I.G., 1967, Recent sediments off the west coast of Barbados, W.I.: Unpubl. Ph.D. dissertation, McGill University, Montreal, Canada, 169 p.
Maiklem, W.R., 1967, Black and brown speckled foraminiferal sand from the southern part of the Great Barrier Reef: Journal of Sedimentary Petrology, v. 37, no. 4, p. 1023–1030.
Multer, H.G., and Hoffmeister, J.E., 1968, Subaerial laminated crusts of the Florida Keys: Geological Society of America Bulletin, v. 79, p. 183–192.
Perkins, R.D., 1977, Depositional framework of Pleistocene rocks in south Florida, in Enos, Paul, and Perkins, R.D., eds., Geological Society of America Memoir 147, p. 131–198.
Pierson, B.J., 1982, Cyclic sedimentation, limestone diagenesis and dolomitization in Upper Cenozoic carbonates of the southeastern Bahamas: Unpubl. Ph.D. dissertation, University of Miami, Coral Gables, FL, 343 p.
Pilkey, O.H., Blackwelder, B.W., Doyle, L.J., Estes, E., and Terlecky, M.P., 1969, Aspects of carbonate sedimentation on the Atlantic Continental Shelf off the southern United States: Journal of Sedimentary Petrology, v. 39, no. 2, p. 744–768.
Robbin, D.M., and Stipp, J.J., 1979, Depositional rate of laminated soilstone crusts, Florida Keys: Journal of Sedimentary Petrology, v. 49, no. 1, p. 0175– 0180.
Shinn, E.A., 1973, Carbonate coastal accretion in an area of longshore transport, NE Qatar, Persian Gulf, in Purser, B.H., ed., The Persian Gulf: New York, Springer-Verlag, p. 179–191.
Shinn, E.A., Lloyd, R.M., and Ginsburg, R.N., 1969, Anatomy of a modern carbonate tidal flat, Andros Island, Bahamas: Journal of Sedimentary Petrology, v. 39, no. 3, p. 1202–1228.
Strasser, A., 1984, Black-pebble occurrence and genesis in Holocene carbonate sediments (Florida Keys, Bahamas and Tunisia): Journal of Sedimentary Petrology, v. 54, no. 4, p. 1097–1109.
Sugden, W., 1966, Pyrite staining of pellety debris in carbonate sediments from the Middle East and elsewhere: Geology Magazine, v. 103, p. 250–256.
Van Straaten, L.M.J.U., 1954, Composition and structure of Recent marine sediments in the. Netherlands: Leidse Geol. Mededel., Leiden, deel 19, p. 1–110.
Wagner, C.W., and Van der Togt, C., 1973, Holocene sediment types and their distribution in the southern Persian Gulf, in Purser, B.H., ed., The Persian Gulf: New York, Springer-Verlag, p. 123–155.
Ward, W.C., Folk, R.L., and Wilson, J.L., 1970, Blackening of eolianite and caliche adjacent to saline lakes, Isla Mujeres, Quintana Roo, Mexico: Journal of Sedimentary Petrology, v. 40, no. 2, p. 548–555.
Williams, S.C., 1985, Stratigraphy, facies evolution, and diagenesis of Late Cenozoic limestones and dolomites, Little Bahama Bank, Bahamas: Unpubl. Ph.D. dissertation, University of Miami, Coral Gables, FL, 216 p.
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 1988 Springer-Verlag New York Inc.
About this chapter
Cite this chapter
Shinn, E.A., Lidz, B.H. (1988). Blackened Limestone Pebbles: Fire at Subaerial Unconformities. In: James, N.P., Choquette, P.W. (eds) Paleokarst. Springer, New York, NY. https://doi.org/10.1007/978-1-4612-3748-8_6
Download citation
DOI: https://doi.org/10.1007/978-1-4612-3748-8_6
Publisher Name: Springer, New York, NY
Print ISBN: 978-0-387-96563-5
Online ISBN: 978-1-4612-3748-8
eBook Packages: Springer Book Archive