Louisiana Petrified Wood

Picture by Paul V. Heinrich

Petrified Wood

Petrified wood consists of a wide variety of minerals including silica, silicates, carbonates, sulfates, sulfides, oxides, and phosphates. They all can permineralize wood to form petrified wood (Adams 1920). However, petrified wood most commonly consists of silica (Si02) in the form of either opal or chert (Stein 1982).

Silicified wood is usually found within one of two types of strata. First, it occurs within accumulations of volcanic ash, tuff, and breccia, e.g. the petrified forests of Yellowstone National Park. Second, silicified wood also occurs within sands, silts, and muds deposited by rivers and streams that have hardened to sandstones, siltstones, and shale. Typically, the sandstones, siltstones, and shales that contain silicified wood also contain redeposited tuffaceous materials or volcanic ash. The silicified wood found in Petrified Forest National Park in Arizona and the Miocene strata of Louisiana and Texas occur within such strata (Knauth 1972:44).

Origin of Petrified Wood

Silicified wood forms in these deposits, because of the presence of dissolved silica within the groundwater. The silica is derived from the dissolution of the volcanic material by the groundwater within the volcanics or sediments. This dissolved silica in the form of monomeric silicic acid attaches itself to the lignin and cellulose of the wood. With time, a layer of the monomeric silicic acid forms on the exposed woody tissues. The monomeric silicic acid dehydrates into silica gel. Additional layers of the monomeric silicic acid attach to this silica gel eventually filling and encasing the wood with silica gel. A rapid loss of water converts the silica gel into amorphous silica (opal) (Leo and Barghoorn 1976; Scurfield and Segnit 1984).

Within 10 to 40 million years, the opal of the silicified wood further dehydrates and crystallizes into microcrystalline quartz (chert). Factors such as temperature and pressure may speed or slow the process, but eventually the opal of the silicified wood becomes chert (Stein 1982). During the change from opal to chert in silicified wood, the relict woody texture may either be retained or lost.

During the silicification process, various materials and minerals may be incorporated into the silica gel. For example, manganese dioxides, iron oxides, organic matter and authegenic clay can alone or in combination color the opal or chert that forms silicified wood. Because each piece of wood becomes silicified in its own local geochemical environment, the trace and major materials and elements that it contains will vary greatly from piece to piece even within the same stratum (Knauth 1972:45; 1981). Therefore, trace element analysis is generally useless in tracing the source of any silicified wood.

Types Of Petrified Woods

Within the Tertiary strata that outcrop in southeast to southwest Texas and into Louisiana, three types of silicified wood can be recognized. They are rather nondescript silicified wood, palm wood, and a massive silicified wood. The nondescript silicified wood consists of silicified wood that possesses a recognizable woody structure. The relict woody structure is fine and nondescript. It is not identifiable without oriented thin sections, specialized references, and comparative material (Blackwell et al. 1983:2). Therefore, this type is best described just as "silicified wood".

The second type of silicified wood is commonly called including the State Fossil "petrified palm wood" by geologists and rock collectors. Palm wood is a group of fossil woods that contain prominent rod-like structures within the regular grain of the silicified wood. Depending upon the angle at which they are cut by fracture, these rod-like structures show up as spots, tapering rods, or continuous lines. The rod-like structures are sclerenchyma bundles that comprise part of the woody tissues that gave vertical strength to the Oligocene and Miocene tree genera, Palmoxylon (Blackwell et al. 1983:4-5).

The third type of silicified wood is massive silicified wood. The silicification of the wood or subsequent transformation of silica gel to opal or chert has obliterated any trace of the grain of the former wood. The destruction of the structure of the silicified wood has resulted in a massive opal or chert that lacks any visible indication of its origin. Because of its variable, massive nature and heterogeneous trace element composition, many investigators, e.g. Jolly (1982) and Jolly and Kerr (1984), have often failed to recognize the nature of this material. The Eagle Hill Chert found within West-Central Louisiana is a local, massive silicified wood (Heinrich 1984). A similar massive silicified wood called "golden palm" occurs in equivalent strata within East-Central Texas (Patterson 1985).

References Cited

Adams, S. F., 1920, Replacement of wood by dolomite. Journal of Geology. vol. 28, no. 6, pp. 356-357.

Blackwell, W. H., Powell, M. J., and Dukes, G. H., 1984, Fossil wood from Bayou Pierre and White Oak Creek, south central Mississippi. Mississippi Geology. vol. 4, no. 2, pp. 1-6.

Heinrich, P. V., 1984, Lithic resources of western Louisiana. Louisiana Archaeology, vol. 13, pp. 102-124.

Hughes, J. T. , 1985 , Conversation with P. V. Heinrich, May 5, 1985, Canyon, Texas.

Jolly, K., 1982, Lithics. In: Eagle Hill: A late Quaternary upland site in western Louisiana. Center for Archaeological Research the University of Texas at San Antonio Special Report. no. 12, pp. 290-300.

Jolly, K., and Kerr, A. C., 1984 , Analysis of Artifacts. In: Occupation and settlement in the uplands of West-Central Louisiana. Center for Archaeological Research the University of Texas at San Antonio Special Report no. 17, pp. 112-149.

Knauth, P. L., 1972, Oxygen and hydrogen isotope ratios in chert and related rocks. Unpublished Ph.D. dissertation, Geology, California Institute of Technology, Stanford.

Knauth, P. L., 1972, 1981, Phone conversation with Paul V. Heinrich, May 3, 1981, Champaign, Illinois.

Leo, R. F., and Barghoorn, E. S., 1976, Silicification of wood. Harvard University Botanical Museum Leaflets. vol. 25, no. 1, pp. 1-47.

Patterson, L. W., 1985, Conversation with Paul V. Heinrich, May 30, 1985, Houston, Texas.

Perttula, T. K., 1984, Patterns of prehistoric lithic raw material utilization in the Caddoan area: the western Gulf Coastal Plain. In: Prehistoric chert exploitation: studies from the Midcontinent. Southern Illinois University at Carbondale Center for Archaeological Investigations Occasional Paper no. 2:129-148.

Plummer, F. B., 1932, Cenozoic Systems in Texas. In: The geology of Texas Volume 1 Stratigraphy. University of Texas Bulletin no. 3232, pp. 519-818.

Scurfield, G. and Segnit, E. R., 1984, Petrifaction of wood by silica minerals. Sedimentary Geology. vol. 39, no. 1, pp. 149-167.

Servello, A. F., 1985, Conversation with Paul V. Heinrich, May 1, 1985, Anacoco, Louisiana.

Servello, A. F., and Bianchi, T. H., 1983, Geomorphology and cultural stratigraphy of the Eagle Hill area of Peason Ridge. In: U.S.L. Fort Polk archaeological survey and cultural resources Management program. University of Southwestern Louisiana, Lafayette.

Stein, C. L., 1982, Silica recrystallization in petrified wood. Journal of Sedimentary Petrology vol. 52, no. 4, pp. 1277-1282.


References Concerning the Petrified Wood of Louisiana and Adjacent Parts of Texas

Berry, Edward Wilber, 1916, The Flora of the Catahoula Sandstone. U.S. Geological Survey Professional Paper no. 98, pp. 227-251.

Berry, Edward Wilber, 1926, Pre-Columbian petrified wood industry. Pan-Am. Geologist. vol. 45, no. 4, pp. 273-276

Brownen, Geneva, 1967 Petrified Wood. Lapidary Journal. vol. 29, no. 12, pp. 2214-2218s.

Chadwick, Michael L., 1988, Identification and geological significance of petrified wood from the Oligocene Catahoula Formation, Jasper County, Texas. Master's Stephen F. Austin State University. Nacogdoches, TX, United States. 77 pp.

Dukes, George H., Jr., 1961, Some Tertiary fossil woods of Louisiana and Mississippi. Am. Jour. Botany. vol. 48, no. 6, pt. 2, p. 540.

Frazier, Don W., 1966, Paragenesis of silica in silicified woods of the Whitsett Formation (Eocene), in (Brazos, Karnes, Polk, McMullen counties) Texas. unpublished Master's thesis, University of Houston. Houston, TX, United States.

Frazier, Don W., 1967, Paragenesis of silica in silicified woods of the Whitsett Formation (Eocene) in Texas. The Texas Journal of Science. vol. 19, no. 4, pp. 415-416.

Hudson, Steve, 1982, Bass fishermen's paradise lures rock collectors with an abundance of gem quality petrified wood. Lost Treasure. vol. 7, no. 8, pp. 64-67.

Hudson, Steve, 1986, Expeditions; Wood hunt. Lapidary Journal. vol. 40, no. 1, pp. 42-48

Hueber, F. M., Nambudiri, E. M. V., Tidwell, W. D., and Wheeler, E. F., 1986, Petrified nyctaginaceous wood from Eocene strata of Texas and Louisiana. American Journal of Botany. vol. 73, no. 5, pp. 701.

Hueber, F. M., Nambudiri, E. M. V., Tidwell, W. D., and Wheeler, E. F., 1991, An Eocene fossil tree with cambial variant wood structure. Review of Palaeobotany and Palynology. vol. 68, no. 3-4, pp. 257-267.

Knowlton, Frank Hall, 1888, Description of two species of "Palmoxylon" from Louisiana. Proceedings of the United States National Museum, no. ?, pp. 89-91.

Manchester, Steven R., 1983, Fossil wood of the Engelhardieae (Juglandaceae) from the Eocene of North America; Engelhardioxylon gen. nov. Botanical Gazette (Chicago). vol. 144, no. 1, pp. 157-163.

McMackin, C. E., 1984, Petrified wood from east to west; some we've liked best. Lapidary Journal. vol. 37, no. 11, pp. 1582-1588.

Naumann, R-C, 1964, Wood replacements of Fayette Co., Texas. Lapidary Journal. vol. 18, no. 1, pp. 187-191.

Plummer, F. B., 1932, Cenozoic Systems in Texas. In: The geology of Texas Volume 1 Stratigraphy. University of Texas Bulletin no. 3232, pp. 519-818

Preston, Nolan E., 1988, Expeditions; a family outing in Southeast Texas. Lapidary Journal. vol. 41, no. 12, pp. 61-62.

Roberts, Leo Bogan, 1940, Petrified wood composed of iron oxide. Journal of Geology. vol. 48, no. 2, pp. 212-213.

Senkayi, A. L., Dixon, J. B., and Hossner, L. R., 1984, Transformation of silica minerals during weathering of petrified wood. Program and Abstracts - Annual Clay Minerals Conference. vol. 21, pp. 104.

Sloat, Lou W., 1977, Texas' Sam Rayburn Dam. Rock & Gem. vol. 7, no. 11, pp. 16-18, 20-22.

Sloat, Lou W., 1977, East Texas petrified forest. Lapidary Journal. vol. 30, no. 10, pp. 2326-2331.

Sloat, Lou W., 1981, "Hunting the Catahoula in Texas". Lapidary Journal. vol. 34, no. 12, pp. 2640-2645.

Thomas, L. H., 1986, Elusive in Louisiana. Lapidary Journal. vol. 40, no. 3, p. 54-56

Zeitner, June Culp, 1988, Louisiana's agatized palm. Lapidary Journal. vol. 42. no. 4, p. 43-46.


References Concerning the Petrified Wood of Mississippi

Blackwell, Will H., 1982, Fossil "dogwood" from the Pleistocene of central Mississippi. Botanical Gazette (Chicago). vol. 143, no. 3, pp. 395-400.

Blackwell, Will H., 1983, Fossil wood from "Sand Hill," western central Mississippi. Bulletin of the Torrey Botanical Club. vol. 110, no. 1, pp. 63-69.

Blackwell, Will H., 1984, Palmoxylon from Bayou Pierre, Copiah/ Claiborne county line, southwestern Mississippi. American Journal of Botany. vol. 71, no. 5, Part 2, pp. 113.

Blackwell, Will H., 1990, Finds of fossil wood from Upper Cretaceous sediments, northeastern Mississippi. Mississippi Geology. vol. 11, no. 2, pp. 7-14.

Blackwell, Will H., and Dukes, George H.,, 1981, Fossil wood from Thompson Creek, Yazoo County, Mississippi. Mississippi Geology. vol. 2, no. 2, pp. 1-6.

Blackwell, Will H., and Dukes, George H., 1982, Fossil hop-hornbeam wood from Rankin County, central Mississippi. Mississippi Geology. vol. 2, no. 4, pp. 10-14.

Blackwell, Will H., Brandenburg, David M., and Dukes, George H., 1981, The structural and phytogeographic affinities of some silicified wood from the mid-Tertiary of West-central Mississippi. In: Geobotany II, Robert C. Romans, pp. 203-220. Plenum Press. New York, NY, United States.

Blackwell, Will H., Chang, Audrey, and Dukes, George H., 1981, Pleistocene fossil wood from West-central Mississippi. Miscellaneous Series Publication - Botanical Society of America. no. 160, pp. 42.

Blackwell, Will H., Powell, Martha J., and Dukes, George H., 1983, Fossil wood from Bayou Pierre and White Oak Creek, southwest-central Mississippi. Mississippi Geology. vol. 4, no. 2, pp. 1-6.

Cahoon, Elizabeth J., 1970, Paraphyllanthioxylon from Alabama. American Journal of Botany. vol. 57, no. 6, Part 2, pp. 759.

Cahoon, Elizabeth J., 1972, Paraphyllanthoxylon alabamense; a new species of fossil dicotyledonous wood. American Journal of Botany. vol. 59, no. 1, pp. 5-11.

Clark, Ronald, 1984a, Distribution, probable origins and mineralogy of some Cretaceous and Tertiary permineralized woods occurring in Mississippi. Science in Mississippi; the Journal of the Mississippi Academy of Sciences. vol. 29, supplement, pp. 19.

Clark, Ronald, 1984b, Distribution, probable origins and mineralogy of some Cretaceous and Tertiary permineralized wood occurring in Mississippi. Abstracts with Programs - Geological Society of America. vol. 16, no. 3, pp. 129.

Dockery, David T. III, 1987, Petrified palm "wood" from Thompson Creek, Yazoo County, Mississippi. Mississippi Geology. vol. 8, no. 2, pp. 10-11.

Fairbanks, Ernest Emerson, 1946, Unique Alabama petrified woods. Mineralogist. vol. 14, no. 3, pp. 121-122.

McMackin, Carleton E., 1984, Petrified wood from east to west; some we've liked best. Lapidary Journal. vol. 37, no. 11, pp. 1582-1588.

Mitchell, James R., 1989, Paleontology; Mississippi petrified wood. Lapidary Journal. vol. 42, no. 12, pp. 41-42.

Roberts, Leo Bogan, 1948, Petrified wood. Journal of the Mississippi Academy of Sciences. vol. 3, pp. 165-166.

Rohn, Kenneth H., 1984, Petrified wood and agate in Mississippi. Jewelry Making Gems & Minerals. vol. 557, pp. 48-50.

Petrified Wood Page

A very nice page on petrified wood is a page about Petrified Wood From Western Washington By Ed Strauss.


Return to Fossil Page
Return to Home Page.
Version 4.0
Dec 18, 2001

Copyright 1996-2002 Paul V. Heinrich All rights reserved.