Clays and Clay Minerals

, Volume 44, Issue 5, pp 652–657 | Cite as

Morphological and Chemical Features of Bioweathered Granitic Biotite Induced by Lichen Activity

  • Jacek Wierzchos
  • Carmen Ascaso


To study the physico-chemical activity of lichens on micaceous components of granitic rocks, samples covered by thalli of Parmelia conspersa (Ehrht) Ach. and Aspicilia intermutans (Nyl.) Arn. were collected and examined with Scanning Electron Microscopy (SEM) equipped with a Back Scattered Electron (BSE) detector and an Energy Dispersive Spectroscopy (EDS) microanalytical system. The bio-physical activity of both lichen species leads to a deep alteration of biotite, which results in detachment, separation and exfoliation of biotite plates. Chemically, the bioweathering process of biotite in the lichenmineral contact zone involves considerable depletion of potassium (K) from interlayer positions in biotite and removal of several elements, corresponding to a 9.7% loss in matter. The sequence of the loss of elements is: K+ » Fetot > Ti4+ ≅ Mg2+. There are also some gains in the order: Ca2+ > Na+ » Al3+ > Si4+ attributed to dissolution of co-existing Ca and Na rich minerals. Geochemical mass balance results suggest the transformation of K-rich biotite to scarcely altered biotite interstratified with a biotite-vermiculite intermediate phase in the lichen bioweathered contact zones.

Key Words

Aspicilia intermutans Biotite Bioweathering Granite Lichens Parmelia conspersa 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. AlDahan AA, Morad S. 1986. Chemistry of detrital biotites and their phyllosilicate intergrowths in sandstones. Clays Clay Miner 34:539–548.CrossRefGoogle Scholar
  2. Ascaso C. 1985. Structural aspects of lichens invading their substrata: Surface physiology of lichens. Madrid: Universidad Complutense. p 87–113.Google Scholar
  3. Ascaso C, Galvan J, Ortega C. 1976. The pedogenic action of Parmelia conspersa, Rhizocarpon geographicum and Umbilicaria postulata. Lichenologist 8:151–171.CrossRefGoogle Scholar
  4. Ascaso C, Galvan J. 1976. Studies of the pedogenic action of lichen acids. Pedologia 16:321–331.Google Scholar
  5. Ascaso C, Brown DH, Rapsch S. 1986. The ultrastructure of the phycobiont of dessicated and hydrated lichens. Lichenologist 18:37–46.CrossRefGoogle Scholar
  6. Ascaso C, Wierzchos J. 1994. Structural aspects of the lichen-rock interface using back-scattered electron imaging. Botan Acta 107:251–256.CrossRefGoogle Scholar
  7. Barshad I, Kishk FM. 1968. Oxidation of ferrous iron in vermiculite and biotite alters fixation and replaceability of potassium. Science 162:1401–1402.CrossRefGoogle Scholar
  8. Barth TW. 1948. Oxygen in rocks. A basis for petrographic calculations. J Geol 56:50–61.CrossRefGoogle Scholar
  9. Craw D, Coombs DS, Kawachi Y. 1982. Interlayered biotitekaolin and other altered biotites, and their relevance to the biotite isograd in eastern Otago, New Zealand. Mineral Mag 45:79–85.CrossRefGoogle Scholar
  10. Dreher P, Niederbudde AE. 1994. Potassium release from micas and characterization of the alteration products. Clay Miner 29:77–85.CrossRefGoogle Scholar
  11. Gilkes RJ. 1973. The alteration products of potassium depleted oxybiotite. Clays Clay Miner 21:303–313.CrossRefGoogle Scholar
  12. Gilkes RJ, Young RC, Quirk JP. 1973. Artificial weathering of oxidized biotite—I. Potassium removal by sodium chloride and sodium tetraphenylboron solutions. Soil Sci Soc Am Proc 37:25–28.CrossRefGoogle Scholar
  13. Gilkes RJ, Suddhiprakarn A. 1979. Biotite alteration in deeply weathered granite. I and II. Clays Clay Miner 27:349–367.CrossRefGoogle Scholar
  14. Goulding KWT. 1983. Thermodynamics and potassium exchange in soils and clay minerals. Adv Agron 36:215–264.CrossRefGoogle Scholar
  15. Iskandar IK, Syers JK. 1972. Metal-complex formation by lichen compounds. J Soil Sci 23:255–265.CrossRefGoogle Scholar
  16. Jones D, Wilson MJ. 1985. Biomineralization in crustose lichens: Biomineralization in lower plants and animals. Oxford: Clarenton Press, p 91–101.Google Scholar
  17. Joy DC. 1991. An introduction to Monte Carlo simulation. Scanning Microscopy 5:329–337.Google Scholar
  18. Lineares J, Caballero E, Reyes E, Huertas F. 1987. Trace element mobility in bentonite formation: The practical applications of trace elements isotopes to environmental biogeochemistry and mineral resources evaluation. Athena: Theophrastus Publishers, p 233–250.Google Scholar
  19. Morad S. 1990. Mica alteration reactions in Jurassic reservoir sandstones from the Haltenbanken area, Offshore Norway. Clays Clay Miner 38:584–590.CrossRefGoogle Scholar
  20. Mortland MM, Lawton K, Uehara G. 1956. Alteration of biotite to vermiculite by plant growth. Soil Sci 82:477–481.CrossRefGoogle Scholar
  21. Pozzuoli A, Viela E, Franco E, Ruiz-Amil A, De la Calle C. 1994. Weathering of biotite to vermiculite in quaternary lahars from Monti Ernici, central Italy. Clay Miner 27:175–184.CrossRefGoogle Scholar
  22. Rausell-Colom JA, Sweatman TR, Wells CB, Norrish K. 1965. Studies in the artificial weathering of mica: Experimental pedology, Proc. Univ. Nottingham 11th Easter Sch. Agric Sci. p 40–72.Google Scholar
  23. Reichenbach H, Graf von, Rich Cl. 1969. Potassium release from muscovite as influenced by particle size. Clays Clay Miner 17:23–29.CrossRefGoogle Scholar
  24. Rich CL 1972. Potassium in soil minerals: Potassium in soil, Proc. 9th. Int. Potash Inst., Landshut, Germany, p 7–24.Google Scholar
  25. Robertson ID, Eggleton RE. 1991. Weathering of granitic muscovite to kaolinite and halloysite and of plagioclasederived kaolinite to halloysite. Clays Clay Miner 39:113–126.CrossRefGoogle Scholar
  26. Ross GJ, Rich Cl. 1974. Effect of oxidation and reduction on potassium exchange of biotite. Clays Clay Miner 22: 355–360.CrossRefGoogle Scholar
  27. Scott AD, Amonette J. 1988. Role of iron in mica weathering: Iron in soils and clay minerals. Dordrecht: D. Reidel. p 537–624.CrossRefGoogle Scholar
  28. Stoch L, Sikora W. 1976. Transformations of micas in the process of kaolinization of granites and gneisses. Clays Clay Miner 24:156–162.CrossRefGoogle Scholar
  29. Syers J, Iskandar IK. 1973. Pedogenic significance of lichens: The lichen. New York: Academic Press, p 225–248.Google Scholar
  30. Weed SB, Davey CB, Cook MG. 1969. Weathering of mica by fungi. Soil Sci Soc Am Proc 33:702–706.CrossRefGoogle Scholar
  31. White SH, Huggett JM, Shaw HE 1985. Electron-optical studies of phyllosilicate intergrowths in sedimentary and metamorphic rocks. Mineral Mag 49:413–423.CrossRefGoogle Scholar
  32. Wierzchos J, Ascaso C. 1994. Application of back-scattered electron imaging to the study of the lichen-rock interface. J Micros 175:54–59.CrossRefGoogle Scholar
  33. Wilson MJ. 1995. Interactions between lichens and rocks, a review. Cryptogam Bot 5:299–305.Google Scholar
  34. Wilson MJ, Jones D. 1983. Lichen weathering of minerals and implication for pedogenesis: Residual deposits: surface related weathering processes and materials. Special Publication of the Geological Society, London: Blackwell, p 5–12.Google Scholar

Copyright information

© The Clay Minerals Society 1996

Authors and Affiliations

  • Jacek Wierzchos
    • 1
    • 2
  • Carmen Ascaso
    • 1
  1. 1.Centro de Ciencias Medioambientales, CSICMadridSpain
  2. 2.Servicio de Microscópia ElectrónicaUniversitat de LleidaLleidaSpain

Personalised recommendations