Hostname: page-component-848d4c4894-wg55d Total loading time: 0 Render date: 2024-05-01T14:23:25.877Z Has data issue: false hasContentIssue false
  • English
  • Français

Crystal-Chemical Changes in an Oxidative Weathering Front in a Georgia Kaolin Deposit

Published online by Cambridge University Press:  01 January 2024

Paul A. Schroeder ,
Robert J. Pruett  and
Nathan D. Melear
Paul A. Schroeder*
Affiliation:
Department of Geology, University of Georgia, Athens, GA 30602-2501, USA
Robert J. Pruett
Affiliation:
IMERYS, Sandersville, GA 31082, USA
Nathan D. Melear
Affiliation:
Department of Geology, University of Georgia, Athens, GA 30602-2501, USA
*
*E-mail address of corresponding author: schroe@uga.edu
Get access Rights & Permissions [Opens in a new window]

Abstract

The Eocene Huber Formation, exposed in the CFI Hall mine south of Irwinton, in Wilkinson County, Georgia, displays colored zones that are a consequence of an oxidative weathering front. These zones vary from very light gray (gray) to pinkish white (pink) to very pale yellow (cream) (Munsell N8, 5YR 8/2 and 2.5Y 8/2, respectively) with increasing degree of oxidation. A representative sample from each zone was collected and analyzed for its chemical, crystallographic and Raman spectroscopic properties. The comparison of these genetically related samples allowed for a quantitatively accurate assessment of anatase’s contribution to the total TiO2 content. All samples contain ∼1.5 wt.% TiO2. Progressing from gray to pink to cream, anatase contents range from half to nearly all the TiO2. The a lattice parameter for anatase is constant in all three kaolins (3.7916 Å), suggesting a constant 4.6 mol.% isomorphous substitution of Fe for Ti.

Phase characterization and mass-balance considerations of the gray, pink and cream kaolins indicate that ilmenite and pyrite are precursor Ti- and Fe-bearing phases in the gray kaolin that undergo oxidation. Pseudorutile is a proposed intermediate phase resulting from the anodic corrosion of ilmenite. Hematite, goethite and anatase are the dominant end-products via dissolution-precipitation from the reactants pyrite and pseudorutile. The removal of Fe sulfides and organic matter and addition of hematite and goethite causes kaolin colors to change from gray to pink. Oxygen diffusing from groundwater in permeable overlying and underlying formations facilitates a process that probably involves aerobic and anaerobic bacteria that utilize Fe from pyrite, hematite and goethite. We postulate that the end result is the mobilization of Fe by siderophores and a kaolin color change from pink to cream.

Keywords

AnataseCrandalliteHematiteIlmeniteKaolinitePseudorutileRutileXRDRaman
Type
Research Article
Information
Clays and Clay Minerals , Volume 52 , Issue 2 , April 2004 , pp. 211 - 220
Copyright
Copyright © 2004, The Clay Minerals Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Baldwin, J.R. Hill, P.G. von Knorring, O. and Oliver, G.J.H., (2000) Exotic aluminium phosphates, natromontebrasite, brazilianite, goyazite, gorceixite and crandallite from rare-element pegmatites in Namibia Mineralogical Magazine 64 1147–1164 10.1180/002646100549940.CrossRefGoogle Scholar
Barker, W.W. and Hurst, V.J., (1992) Bacterial trace fossils in Eocene kaolin of the Huber Formation of Georgia: Phylloderma microsphaerodes, n. ichnogen., n ichnosp Ichnos 2 55–60 10.1080/10420949209380075.CrossRefGoogle Scholar
Berner, R.A. and Raiswell, R., (1984) C/S method for distinguishing freshwater from marine sedimentary rocks Geology 12 365–368 10.1130/0091-7613(1984)12<365:CMFDFF>2.0.CO;2.2.0.CO;2>CrossRefGoogle Scholar
Canfield, D.E. Raiswell, R. and Bottrell, S., (1992) The reactivity of sedimentary iron minerals toward sulfide American Journal of Science 292 659–683 10.2475/ajs.292.9.659.CrossRefGoogle Scholar
ČernÅý, P. Burt, D.M. and Bailey, S.W., (1984) Paragenesis, crystallochemical characteristics and geochemical evolution of micas in pegmatites Micas Washington, D.C Mineralogical Society of America 257–298 10.1515/9781501508820-012.CrossRefGoogle Scholar
Cornell, R.M. and Schwertmann, U., (1996) The Iron Oxides: Structure, Properties, Reactions, Occurrences and Uses Weinheim, Germany VCH Velagsgesellschaft, mbH 573 pp.Google Scholar
Dombrowski, T., Murray, H.H. Bundy, W. and Harvey, C., (1993) Theories of origin for the Georgia kaolins: A review Kaolin Genesis and Utilization Boulder, Colorado The Clay Minerals Society 75–97.Google Scholar
Force, E.R., (1991) Geology of titanium deposits Boulder, Colorado Geological Society of America 112 pp.Google Scholar
Grey, I.E. and Reid, A.F., (1975) The structure of pseudorutile and its role in the natural alteration of ilmenite American Mineralogist 60 898–906.Google Scholar
Hall, R.B. Foord, E.E. Keller, D.J. and Keller, W.D., (1997) Phosphates in some Missouri refractory clays Clays and Clay Minerals 45 353–364 10.1346/CCMN.1997.0450306.CrossRefGoogle Scholar
Hersman, L. Lloyd, T. and Sposito, G., (1995) Siderophore-promoted dissolution of hematite Geochimica et Cosmochimica Acta 59 327–3330 10.1016/0016-7037(95)00221-K.CrossRefGoogle Scholar
Hinckley, D.N., (1963) Variability in “crystallinity” values among the kaolin deposits of the Coastal Plain of Georgia and South Carolina Clays and Clay Minerals 11 229–235 10.1346/CCMN.1962.0110122.CrossRefGoogle Scholar
Hurst, V.J. and Pickering, S., (1989) Cretaceous-Tertiary strata and kaolin deposits in the inner Coastal Plain of Georgia Upper Cretaceous and Cenozoic Geology of the Southeastern Atlantic Coastal Plain, Field Trip Guidebook T172 Washington, D.C American Geophysical Union 1–22.Google Scholar
Hurst, V.J. and Pickering, S.M., (1997) Origin and classification of coastal-plain kaolins, southeastern USA, and the role of groundwater and microbial action Clays and Clay Minerals 45 274–285 10.1346/CCMN.1997.0450215.CrossRefGoogle Scholar
Hurst, V.J. Schroeder, P.A. and Styron, R.W., (1997) Accurate quantification of quartz and other phases by powder X-ray diffractometry Analytica Chimica Acta 337 233–252 10.1016/S0003-2670(96)00425-4.CrossRefGoogle Scholar
Kampf, N. and Schwertmann, U., (1982) Quantitative determination of goethite and hematite in kaolinitic soils by X-ray diffraction Clay Minerals 17 359–363 10.1180/claymin.1982.017.3.08.CrossRefGoogle Scholar
Klug, H P and Alexander, L.E., (1974) X-ray diffraction Procedures for Polycrystalline and Amorphous Materials New York John Wiley & Sons 966 pp.Google Scholar
Larrett, M.J.W. and Spencer, W.G., (1971) Contributions to Australasian Mineralogy, 3. “Pseudorutile” from South Neptune Island, South Australia Amdel Bulletin 12 74–80.Google Scholar
Maurice, P.A. Lee, Y.J. and Hersman, L.E., (2000) Dissolution of Al-substituted goethites by an aerobic Pseudomonas mendocina var. bacteria Geochimica et Cosmochimica Acta 68 1363–1374 10.1016/S0016-7037(99)00404-4.CrossRefGoogle Scholar
Mordberg, L.E., (1999) Geochemical evolution of a Devonian di apore-crandallite-svanbergite-bearing weathering profile in the Middle Timan, Russia Journal of Geochemical Exploration 66 353–361 10.1016/S0375-6742(99)00021-7.CrossRefGoogle Scholar
Palmer, D.C., (2003) CrytallDifract v. 4.0.2 — A program to calculate powder X-ray diffraction patterns from crystallographic data P.O. Box 183, Bicester, Oxfordshire OX26 3TA, UK CrystalMaker Software.Google Scholar
Pruett, R.J., (2000) Georgia kaolin: Development of a leading industrial mineral Mining Engineering 52 21–27.Google Scholar
Pruett, R.J. Yuan, J. Keller, P. and Bradley, J., (1996) Trace element chemistry of anatase in Georgia kaolins Annual Meeting of the Clay Minerals Society Tennessee Gatlinburg 133 Abstracts with Program.Google Scholar
Railsback, B. (2001) An earth scientist’s periodic table of the elements and their ions. Earth System Processes — Global Meeting, Edinburgh, Scotland. Abstracts with Program. .Google Scholar
Rassmussen, B. Buick, R. and Taylor, W.R., (1998) Removal of oceanic REE by authigenic precipitation of phosphatic minerals Earth and Planetary Science Letters 164 135–149 10.1016/S0012-821X(98)00199-X.CrossRefGoogle Scholar
Santelli, C.M. Welch, S.A. Westrich, H.R. and Banfield, J.F., (2001) The effect of Fe-oxidizing bacteria on Fe-silicate mineral dissolution Chemical Geology 180 99–115 10.1016/S0009-2541(01)00308-4.CrossRefGoogle Scholar
Schroeder, P.A. and Wenner, D., (1999) Common minerals of Graves Mountain, Georgia Graves Mountains, Georgia: Mineralogy, Economic geology and environmental problems Athens, Georgia University of Georgia Department of Geology 12–32.Google Scholar
Schroeder, P.A. and Ingall, E.D., (1994) A method for the determination of nitrogen in clays, with application to the burial diagenesis of shales Journal of Sedimentary Research A64 694–697 10.1306/D4267E79-2B26-11D7-8648000102C1865D.CrossRefGoogle Scholar
Schroeder, P.A. and Pruett, R., (1996) Iron ordering in kaolinites: Insights from 29Si and 27Al NMR spectroscopy American Mineralogist 81 26–38 10.2138/am-1996-1-204.CrossRefGoogle Scholar
Schroeder, P.A. and Shiflet, J., (2000) Ti-bearing phases in an east Georgia kaolin deposit Clays and Clay Minerals 48 151–158 10.1346/CCMN.2000.0480201.CrossRefGoogle Scholar
Schroeder, P.A. Kim, J.G. and Melear, N.D., (1997) Mineralogical and textural criteria for recognizing remnant Cenozoic deposits on the Piedmont: Evidence from Sparta and Greene County, Georgia, U.S.A Sedimentary Geology 108 195–206 10.1016/S0037-0738(96)00054-1.CrossRefGoogle Scholar
Schroeder, P.A. Melear, N.D. West, L.T. and Hamilton, D.A., (2000) Meta-gabbro weathering in the Georgia Piedmont, USA: Implications for global silicate weathering rates Chemical Geology 163 235–245 10.1016/S0009-2541(99)00129-1.CrossRefGoogle Scholar
Schroeder, P.A. Le Govlan, J.J. and Roden, M.D., (2002) Weathering of ilmenite from granite and chlorite schist in the Georgia Piedmont, USA American Mineralogist 87 1616–1625 10.2138/am-2002-11-1211.CrossRefGoogle Scholar
Schroeder, P.A. Melear, N.D. and Pruett, R.J., (2003) Quantitative analysis of anatase in Georgia kaolins using Raman spectroscopy Applied Clay Science 23 299–308 10.1016/S0169-1317(03)00129-7.CrossRefGoogle Scholar
Schwertmann, U. Friedl, J. Pfab, G. and Gehring, A.U., (1995) Iron substitution in soil and synthetic anatase Clays and Clay Minerals 43 599–606 10.1346/CCMN.1995.0430509.CrossRefGoogle Scholar
Seaman, J.C. Bertsch, P.M. and Strom, R.N., (1997) Characterization of colloids mobilized from southeastern coastal plain sediments Environmental Science and Technology 31 2782–2790 10.1021/es961075z.CrossRefGoogle Scholar
Shelobolina, E., (2000) Role of microorganism in development of commercial grade kaolins Geology of the Commercial Kaolin Mining District of Central and Eastern Georgia 20 45–56.Google Scholar
Shiflet, J.E., (1999) Ti-bearing phases in an east-Georgia kaolin deposit Athens, Georgia University of Georgia, Department of Geology M.S. thesis.Google Scholar
Singh, B. and Gilkes, R.J., (1991) Concentration of iron oxides from soil clays by 5 M NaOH treatment; the complete removal of sodalite and kaolin Clay Minerals 26 463–472 10.1180/claymin.1991.026.4.02.CrossRefGoogle Scholar
Viswanathan, S., (1973) A geochemical study of niobium distribution and of Nb-Ti and Nb-Zr relations in some phyllosilicates Current Science 42 524–527.Google Scholar
Weibel, R., (1998) Diagenesis in oxidising and locally reducing conditions — an example from the Triassic Skagarrek Formation Denmark Sedimentary Geology 25 259–276 10.1016/S0037-0738(98)00085-2.CrossRefGoogle Scholar
White, N.G. Dixon, J.B. Weaver, R.M. and Kunkle, A.C., (1991) Genesis and morphology of iron sulfides in gray kaolins Clays and Clay Minerals 39 70–76 10.1346/CCMN.1991.0390109.CrossRefGoogle Scholar