Hostname: page-component-8448b6f56d-tj2md Total loading time: 0 Render date: 2024-04-19T12:58:53.969Z Has data issue: false hasContentIssue false
  • English
  • Français

Characteristics and Origin of Rock Varnish from the Hyperarid Coastal Deserts of Northern Peru

Published online by Cambridge University Press:  20 January 2017

Charles E. Jones
Charles E. Jones*
Affiliation:
Department of Geology, Stanford University, Stanford, California 94305
Get access Rights & Permissions [Opens in a new window]

Abstract

The characteristics of a new type of rock varnish from the hyperarid coastal deserts of northern Peru, combined with laboratory experiments on associated soil materials, provide new insights into the formation of rock varnish. The Peruvian varnish consists of an Fe-rich, Mn-poor component covering up to 95% of a varnished surface and a Fe-rich, Mn-rich component found only in pits and along cracks and ridges. The alkaline soils plus the catalytic Fe oxyhydroxides that coat much of the varnish surfaces make the Peruvian situation ideal for physicochemical precipitation of Mn. However, the low Mn content of the dominant Fe-rich, Mn-poor component suggests that such precipitation is minor. This, plus the presence of abundant bacteria in the Mn-rich varnish and the recorded presence of Mn-precipitating bacteria in varnish elsewhere, suggests that bacteria are almost solely responsible for Mn-precipitation in rock varnish. A set of experiments involving Peruvian soil samples in contact with water-CO2 solutions indicates that natural fogs or dews release Mn but not Fe when they come in contact with eolian materials on rock surfaces. This mechanism may efficiently provide Mn to bacteria on varnishing surfaces. The lack of Fe in solution suggests that a large but unknown proportion of Fe in varnish may be in the form of insoluble Fe oxyhydroxides sorbed onto the clay minerals that form the bulk of rock varnish. The results of this study do not substantively change R. I. Dorn's paleoenvironmental interpretations of varnish Mn:Fe ratios, but they do suggest areas for further inquiry.

Type
Research Article
Information
Quaternary Research , Volume 35 , Issue 1 , January 1991 , pp. 116 - 129
Copyright
University of Washington

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

Bartlett, R. Soil redox behavior Sparks, D.L. Soil Physical Chemistry 1986 CRC Press Boca Raton, FL Google Scholar
Behra, P. Sigg, L. Evidence for redox cycling of iron in atmospheric water droplets Nature (London) 344 1990 419 421 CrossRefGoogle Scholar
Corstea, D.D. Formation of hydroxy -A1 and -Fe interlayers in montmorillonite and vermiculite: Influence of particle size and temperature Clays and Clay Minerals 16 1968 231 238 CrossRefGoogle Scholar
Crerar, D.A. Cormick, R.K. Barnes, H.L. Geochemistry of Mn: An overview Varentsov, I.M. Grasselly, G.Y. Geology and Geochemistry of Manganese Vol. 1 1980 E. Schweizerbart'sche Verlagsbuchhandlung Stuttgart Google Scholar
Curtiss, B. Adams, J.B. Ghiorso, M.S. Origin, development, and chemistry of silica-alumina rock coatings from the semi-arid regions of the island of Hawaii Geochimica et Cosmochimica Acta 49 1985 49 56 CrossRefGoogle Scholar
Dorn, R.I. Cause and implications of rock varnish microenvironmental laminations Nature (London) 310 1984 767 770 CrossRefGoogle Scholar
Dorn, R.I. Rock varnish as an indicator of aeolian environmental change Nickling, W.G. Aeolian Geomorphology 1986 Allen and Unwin London 291 307 Google Scholar
Dorn, R.I. A rock varnish interpretation of alluvial fan development in Death Valley, California National Geographic Research 4 1988 56 73 Google Scholar
Dorn, R.I. A comment on “A note on the characteristics and possible origins of desert varnishes from southeast Morocco” Earth Surface Processes and Landforms 14 1989 167 170 by Drs. Smith and Whalley CrossRefGoogle Scholar
Dorn, R.I. Quaternary alkalinity fluctuations recorded in rock varnish microlaminations on western U.S.A. volcanics Palaeogeography, Palaeoclimatology, Palaeoecology 76 1990 291 310 CrossRefGoogle Scholar
Dorn, R.I. DeNiro, M.J. Ajie, H.O. Isotopic evidence for climatic influence on alluvial-fan development in Death Valley, California Geology 15 1987 108 110 2.0.CO;2>CrossRefGoogle Scholar
Dorn, R.I. Oberlander, T.M. Microbial origin of desert varnish Science 213 1981 1245 1247 CrossRefGoogle ScholarPubMed
Dorn, R.I. Oberlander, T.M. Rock varnish origin, characteristics, and usage Zeitschrift fur Geomorphologie 25 1981 420 436 CrossRefGoogle Scholar
Dorn, R.I. Oberlander, T.M. Rock varnish Progress in Physical Geography 74 1982 308 322 Google Scholar
Elvidge, C.D. Iverson, R.M. Regeneration of desert pavement and varnish Webb, R.H. Wilshire, H.G. Environmental Effects of Off-Road Vehicles 1983 Springer-Verlag New York 225 243 CrossRefGoogle Scholar
Engel, C.G. Sharp, R.P. Chemical data on desert varnish Geological Society of America Bulletin 69 1958 487 518 CrossRefGoogle Scholar
Farr, T.G. Adams, J.B. Rock coatings in Hawaii Geological Society of America Bulletin 95 1984 1077 1083 2.0.CO;2>CrossRefGoogle Scholar
Fisk, E.P. Desert glaze Journal of Sedimentary Petrology 41 1971 1136 1137 CrossRefGoogle Scholar
Ghiorse, W.C. Balkwill, D.L. Enumeration and morphological characterization of bacteria indigenous to subsurface environments Proceedings of the 39th General Meeting of the Society for Industrial Microbiology St. Paul, MN, Aug. 1982 Developments in Industrial Microbiology Vol. 24 1983 Google Scholar
Glasby, G.P. McPherson, J.G. Kohn, B.P. Johnston, J.H. Keys, J.R. Freeman, A.G. Tricker, M.J. Desert varnish in southern Victoria Land, Antarctica New Zealand Journal of Geology and Geophysics 24 1981 389 397 Google Scholar
Harrington, C.D. Whitney, J.W. Scanning electron microscope method for rock varnish dating Geology 15 1987 967 970 2.0.CO;2>CrossRefGoogle Scholar
Hem, J.D. Redox processes at surfaces of MnO2 and their effects on aqueous metal ions Chemical Geology 21 1978 199 218 CrossRefGoogle Scholar
Hooke, R.LeB. Yang, H. Weiblen, P.W. Desert varnish: An electron microprobe study Journal of Geology 77 1969 275 288 CrossRefGoogle Scholar
Johnston, J.H. Cardile, C.M. Coote, G.E. Sparks, R.J. Wallace, G. McMillan, J.W. Pummeny, F.C. Longworth, G. Desert varnish in Antarctica: A nuclear microprobe and backscattered iron-57 Mossbauer spectroscopic study Chemical Geology 42 1984 189 201 CrossRefGoogle Scholar
Johnston, J.H. Cardile, C.M. The characterization of the iron oxide phase in desert varnish from Antarctica using backscattered conversion electron and X-ray Mossbauer spectroscopy Chemical Geology 45 1984 73 90 CrossRefGoogle Scholar
Krauskopf, K.B. Introduction to Geochemistry 1967 McGraw-Hill New York Google Scholar
Krumbein, W.E. Jens, K. Biogenic rock varnishes of the Negev Desert (Israel): An ecological study of iron and manganese transformation by cyanobacteria and fungi Oecologia 50 1981 25 38 CrossRefGoogle ScholarPubMed
Morgan, J.J. Sung, W. Stone, A. Chemistry of metal oxides in natural waters: Catalysis of the oxidation of Mn(II) by gamma-FeOOH and reductive dissolution of Mn(III) and Mn(IV) oxides Irgolic, K.J. Martell, A.E. Environmental Inorganic Chemistry 1985 VCH Deerfield Beach, FL Google Scholar
Oberlander, T.M. Interpretation of rock varnish from the Atacama Desert Association of American Geographers Abstracts 1982 311 Google Scholar
Palmer, F.E. Staley, J.T. Murray, R.G.E. Counsell, T. Adams, J.B. Identification of manganese-oxidizing bacteria from desert varnish Geomicrobiology Journal 4 1985 343 360 CrossRefGoogle Scholar
Perry, R.S. Adams, J. Desert varnish: Evidence of cyclic deposition of manganese Nature (London) 278 1978 489 491 CrossRefGoogle Scholar
Potter, R.M. Rossman, G.R. Desert varnish: The importance of clay minerals Science 196 1977 1446 1448 CrossRefGoogle ScholarPubMed
Potter, R.M. Rossman, G.R. The manganese- and iron-oxide mineralogy of desert varnish Chemical Geology 25 1979 79 94 CrossRefGoogle Scholar
Rott, U. Physical, chemical, and biological aspects of the removal of Fe and Mn underground Water Supply 3 1985 143 150 Google Scholar
Smith, B.J. Whalley, W.B. A note on the characteristics and possible origins of desert varnishes from southeast Morocco Earth Surface Processes and Landforms 13 1988 251 258 CrossRefGoogle Scholar
Staley, J.T. Jackson, M.J. Palmer, F.E. Adams, J.B. Borns, D.J. Curtiss, B. Taylor-George, S. Desert varnish coatings and microcolonial fungi on rocks of the Gibson and Great Victoria Deserts, Australia BMR Journal of Geology and Geophysics 8 1983 83 87 Google Scholar
Staley, J.T. Palmer, F. Adams, J.B. Microcolonial fungi: Common inhabitants on desert rocks? Science 215 1982 1093 1095 CrossRefGoogle ScholarPubMed
Sung, W. Morgan, J.J. Kinetics and products of ferrous iron oxygenation in aqueous systems Environmental Science and Technology 14 1980 561 568 CrossRefGoogle Scholar
Taylor-George, S. Palmer, F.E. Staley, J.T. Borns, D.J. Curtiss, B. Adams, J.B. Fungi and bacteria involved in desert varnish formation Microbial Ecology 9 1983 227 245 CrossRefGoogle ScholarPubMed
Wells, L.E. An alluvial record of El Niño events from northern coastal Peru Journal of Geophysical Research 92 C13 1987 14,463 14,470 CrossRefGoogle Scholar
Wilson, D.E. Surface and complexation effects on the rate of Mn2+ oxidation in natural waters Geochimica et Cosmochimica Acta 44 1980 1311 1317 CrossRefGoogle Scholar