Biomarkers of black shales formed by microbial mats, Late Mesoproterozoic (1.1Ga) Taoudeni Basin, Mauritania

Precambrian Research

Volumn 196-197, Issue , 2012, Pages 113-127

  Blumenberg, Martin ^a   Thiel, Volker ^a   Riegel, Walter ^a   Kah, Linda C ^b   Reitner, Joachim ^a  

^a UNIVERSITY OF GÖTTINGEN   (Germany)

^b UNIVERSITY OF TENNESSEE   (United States)

Author keywords

Acritarchs; Biomarkers; High aromaticity; Hopanes; Late Mesoproterozoic; Taoudeni Basin

Indexed keywords

ACRITARCH; BIOMARKER; BLACK SHALE; CONCENTRATION (COMPOSITION); DENITRIFICATION; DEPOSITIONAL ENVIRONMENT; EXOPOLYMER; GEOACCUMULATION; MICROBIAL COMMUNITY; MICROBIAL MAT; MICROFACIES; ORGANIC CARBON; PALEOENVIRONMENT; PRODUCTIVITY; PROTEROZOIC;

TAOUDENNI BASIN;

ACRITARCHA; ALGAE; EUKARYOTA; PHOTOBACTERIA;

EID: 84055178957     PISSN: 03019268     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.precamres.2011.11.010     Document Type: Article

References (103)

1. Allwood A.C., Walter M.R., Kamber B.S., Marshall C.P., Burch I.W. Stromatolite reef from the Early Archaean era of Australia. Nature 2006, 441:714-718.
2. Almendros G., Dorado J., González-Vila F.J., Martin F. Pyrolysis of carbohydrate-derived macromolecules: its potential in monitoring the carbohydrate signature of geopolymers. Journal of Analytical and Applied Pyrolysis 1997, 40-41:599-610.
3. Anbar A.D., Knoll A.H. Proterozoic ocean chemistry and evolution: a bioinorganic bridge?. Science 2002, 297:1137-1142.
4. Aquino Neto F.R., Trendel J.M., Restle A., Connan J., Albrecht P. Occurrence and formation of tricyclic and tetracyclic terpanes in sediments and petroleums. Advances in Organic Geochemistry 1981 1983, 659-676. John Wiley & Sons, New York. M. Bjorøy (Ed.).
5. Arouri K.R., Greenwood P.F., Walter M.R. Biological affinities of Neoproterozoic acritarchs from Australia: microscopic and chemical characterisation. Organic Geochemistry 2000, 31:75-89.
6. Berner R.A. Sedimentary pyrite formation: an update. Geochimica et Cosmochimica Acta 1984, 48:605-615.
7. Berry A., Harriott O., Moreau R., Osman S., Benson D., Jones A. Hopanoid lipids compose the Frankia vesicle envelope, presumptive barrier of oxygen diffusion to nitrogenase. PNAS 1993, 90:6091-6094.
8. Bertrand-Sarfati J., Moussine-Pouchkine A. Is cratonic sedimentation consistent with available models? An example from the Upper Proterozoic of the West African craton. Sedimentary Geology 1988, 58:255-276.
9. Blumenberg M., Mollenhauer G., Zabel M., Reimer A., Thiel V. Decoupling of bio- and geohopanoids in sediments of the Benguela Upwelling System (BUS). Organic Geochemistry 2010, 41:1119-1129.
10. Blumenberg M., Seifert R., Kasten S., Bahlmann E., Michaelis W. Euphotic zone bacterioplankton sources major sedimentary bacteriohopanepolyols in the Holocene Black Sea. Geochimica et Cosmochimica Acta 2009, 73:750-766.
11. Boreham C.J., Crick I.H., Powell T.G. Alternative calibration of the Methylphenanthrene Index against vitrinite reflectance: application to maturity measurements on oils and sediments. Organic Geochemistry 1988, 12:289-294.
12. Bravo J.-M., Perzl M., Härtner T., Kannenberg E.L., Rohmer M. Novel methylated triterpenoids of the gammacerane series from the nitrogen-fixing bacterium Bradyrhizobium japonicum USDA 110. European Journal of Biochemistry 2001, 268:1323-1331.
13. Brocks J.J. The succession of primary producers in Proterozoic oceans. Geochimica et Cosmochimica Acta 2009, 73:A161.
14. Brocks J.J. Millimeter-scale concentration gradients of hydrocarbons in Archean shales: live-oil escape or fingerprint of contamination?. Geochimica et Cosmochimica Acta 2011, 75:3196-3213.
15. Brocks J.J., Grosjean E., Logan G.A. Assessing biomarker syngeneity using branched alkanes with quaternary carbon (BAQCs) and other plastic contaminants. Geochimica et Cosmochimica Acta 2008, 72:871-888.
16. Brocks J.J., Logan G.A., Buick R., Summons R.E. Archean molecular fossils and the early rise of eukaryotes. Science 1999, 285:1033-1036.
17. Brocks J.J., Buick R., Logan G.A., Summons R.E. Composition and syngeneity of molecular fossils from the 2.78 to 2.45 billion-year-old Mount Bruce Supergroup, Pilbara Craton, Western Australia. Geochimica et Cosmochimica Acta 2003, 67:4289-4319.
18. Brocks J.J., Love G.D., Snape C.E., Logan G.A., Summons R.E., Buick R. Release of bound aromatic hydrocarbons from late Archean and Mesoproterozoic kerogens via hydropyrolysis. Geochimica et Cosmochimica Acta 2003, 67:1521-1530.
19. Brocks J.J., Love G.D., Summons R., Knoll A.H., Logan G.A., Bowden S.A. Biomarker evidence for green and purple sulphur bacteria in a stratified Palaeoproterozoic sea. Nature 2005, 437:866-870.
20. Brocks J.J., Pearson A. Building the biomarker tree of life. Reviews in Mineralogy and Geochemistry 2005, 59:233-258.
21. Brocks J.J., Schaeffer P. Okenane, a biomarker for purple sulfur bacteria (Chromatiaceae), and other new carotenoid derivatives from the 1640 Ma Barney Creek Formation. Geochimica et Cosmochimica Acta 2008, 72:1396-1414.
22. Brocks J.J., Summons R. Sedimentary hydrocarbons, biomarkers for early life. Treatise on Geochemistry 2003, 8:63-115.
23. Butterfield N.J. Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes. Paleobiology 2000, 26:386-404.
24. Canfield D.E. A new model for Proterozoic ocean chemistry. Nature 1998, 396:450-453.
25. Canfield D.E. The early history of atmospheric oxygen: homage to Robert M. Garrels. Annual Review of Earth and Planetary Sciences 2005, 33:1-36.
26. Delecat S., Arp G., Reitner J. Aftermath of the Triassic-Jurassic boundary crisis: spiculite formation on drowned Triassic Steinplatte reef-slope by communities of hexactinellid sponges. Lecture Notes in Earth Sciences 2010, 131:355-391.
27. Doering S., di Primio R., Horsfield B. New insights on the Precambrian petroleum system of the Taoudeni Basin based on shallow drilling results. 24th International Meeting on Organic Geochemistry 2009, 360.
28. Doughty D.M., Hunter R.C., Summons R.E., Newman D.K. 2-Methylhopanoids are maximally produced in akinetes of Nostoc punctiforme: geobiological implications. Geobiology 2009, 7:1-9.
29. Dutkiewicz A., Volk H., Ridley J., George S.C. Geochemistry of oil in fluid inclusions in a middle Proterozoic igneous intrusion: implications for the source of hydrocarbons in crystalline rocks. Organic Geochemistry 2004, 35:937-957.
30. Eigenbrode J.L., Freeman K.H., Summons R.E. Methylhopane biomarker hydrocarbons in Hamersley Province sediments provide evidence for Neoarchean aerobiosis. Earth and Planetary Science Letters 2008, 273:323-331.
31. Fennel K., Follows M., Falkowski P.G. The co-evolution of the nitrogen, carbon and oxygen cycles in the Proterozoic ocean. American Journal of Science 2005, 305:526-545.
32. Fowler M.G., Douglas A.G. Saturated hydrocarbon biomarkers in oils of Late Precambrian age from Eastern Siberia. Organic Letters 1987, 11:201-213.
33. Goodman E.E., Kah L.C. Trace sulfate concentrations as an indicator of depositional environment: examination of possible calcitized evaporates from the Proterozoic Atar Group, Mauritania. GSA Meeting 2004, 78. Abstracts with Programs.
34. Greenwood P.F., Arouri K.R., George S.C. Tricyclic terpenoid composition of Tasmanites kerogen as determined by pyrolysis GC-MS. Geochimica et Cosmochimica Acta 2000, 64:1249-1263.
35. Greenwood P.F., Arouri K.R., Logan G.A., Summons R.E. Abundance and geochemical significance of C2n dialkylalkanes and highly branched C3n alkanes in diverse meso- and neoproterozoic sediments. Organic Geochemistry 2004, 35:331-346.
36. Grice K., Schaeffer P., Schwark L., Maxwell J.R. Changes in palaeoenvironmental conditions during deposition of the Permian Kupferschiefer (Lower Rhine Basin, northwest Germany) inferred from molecular and isotopic compositions of biomarker components. Organic Geochemistry 1997, 26:677-690.
37. Hartgers W.A., Damsté J.S.S., de Leeuw J.W. Geochemical significance of alkylbenzene distributions in flash pyrolysates of kerogens, coals, and asphaltenes. Geochimica et Cosmochimica Acta 1994, 58:1759-1775.
38. 13C contents of sedimentary organic compounds: principles and evidence. Marine Geology 1993, 113:115-125.
39. Hayes J.M. Fractionation of the isotopes of carbon and hydrogen in biosynthetic processes. Stable Isotope Geochemistry, Reviews in Mineralogy and Geochemistry 2001, 225-278. Mineralogical Society of America, Washington, DC. J.W. Valley, D.R. Cole (Eds.).
40. Huntley J.W., Xiao S., Kowalewski M. 1.3 billion years of acritarch history: an empirical morphospace approach. Precambrian Research 2006, 144:52-68.
41. Imbus S.W., Macko S.A., Douglas Elmore R., Engel M.H. Stable isotope (C, S, N) and molecular studies on the Precambrian nonesuch Shale (Wisconsin-Michigan, U.S.A.): evidence for differential preservation rates, depositional environment and hydrothermal influence. Chemical Geology: Isotope Geoscience Section 1992, 101:255-281.
42. Javaux E.J., Knoll A.H., Walter M.R. TEM evidence for eukaryotic diversity in mid-Proterozoic oceans. Geobiology 2004, 2:121-132.
43. Javaux E.J., Marshall C.P., Bekker A. Organic-walled microfossils in 3.2-billion-year-old shallow-marine siliciclastic deposits. Nature 2010, 463:934-938.
44. Johnston D.T., Wolfe-Simon F., Pearson A., Knoll A.H. Anoxygenic photosynthesis modulated Proterozoic oxygen and sustained Earth's middle age. Proceedings of the National Academy of Sciences 2009, 106:16925-21692.
45. Kah L.C., Bartley J.K. Protracted oxygenation of the Proterozoic biosphere 2011, International Geology Review, 1424-1442.
46. Kah L.C., Bartley J.K., Stagner A.F. Reinterpreting a Proterozoic enigma: Conophyton-Jacutophyton stromatolites of the Mesoproterozoic Atar Group, Mauritania. IAS Special Publication 2009, 41:277-295.
47. Kah, L.C., Bartley, J.K., Teal, D.A., in review. Chemostratigraphy of the late Mesoproterozoic Atar Group, Mauritania: muted isotopic variability, facies correlation, and global isotopic trends. Precambrian Research.
48. Kah L.C., Lyons T.W., Chesley J.T. Geochemistry of a 1.2Ga carbonate-evaporite succession, northern Baffin and Bylot Islands: implications for Mesoproterozoic marine evolution. Precambrian Research 2001, 111:203-234.
49. Kah L.C., Lyons T.W., Frank T.D. Low marine sulphate and protracted oxygenation of the Proterozoic biosphere. Nature 2004, 431:834-838.
50. Killops S., Killops V. Introduction to Organic Geochemistry 2005, Blackwell publishing, Oxford. 2nd ed.
51. Klotz M.G., Stein L.Y. Nitrifier genomics and evolution of the nitrogen cycle. FEMS Microbiology Letters 2008, 278:146-156.
52. Knoll A.H., Javaux E.J., Hewitt D., Cohen P. Eukaryotic organisms in Proterozoic oceans. Philosophical Transactions of the Royal Society B: Biological Sciences 2006, 361:1023-1038.
53. Koopmans M.P., Koster J., Van Kaam-Peters H.M.E., Kenig F., Schouten S., Hartgers W.A., de Leeuw J.W., Sinninghe Damste J.S. Diagenetic and catagenetic products of isorenieratene: molecular indicators for photic zone anoxia. Geochimica et Cosmochimica Acta 1996, 60:4467-4496.
54. Koopmans M.P., Schouten S., Kohnen M.E.L., Sinninghe Damsté J.S. Restricted utility of aryl isoprenoids as indicators for photic zone anoxia. Geochimica et Cosmochimica Acta 1996, 60:4873-4876.
55. Köster J., Schouten S., Sinninghe Damsté J.S., De Leeuw J.W. Reconstruction of depositional environment of Toarcian marlstones (Allgäu Formation, Tyrol/Austria) using biomarkers and compound specific carbon isotope analyses. Organic Geochemistry: Developments and Applications of Energy, Climate, Environment and Human History 1995, A.I.G.O.A., San Sebastian. J.O. Grimalt, C. Dorronsoro (Eds.).
56. Logan G.A., Calver C.R., Gorjan P., Summons R.E., Hayes J.M., Walter M.R. Terminal Proterozoic mid-shelf benthic microbial mats in the Centralian Superbasin and their environmental significance. Geochimica et Cosmochimica Acta 1999, 63:1345-1358.
57. Logan G.A., Hayes J.M., Hieshima G.B., Summons R.E. Terminal Proterozoic reorganization of biogeochemical cycles. Nature 1995, 376:53-56.
58. Logan G.A., Hinman M.C., Walter M.R., Summons R.E. Biogeochemistry of the 1640Ma McArthur River (HYC) lead-zinc ore and host sediments, Northern Territory, Australia. Geochimica et Cosmochimica Acta 2001, 65:2317-2336.
59. Lyons T.W., Anbar A.D., Severmann S., Scott C., Gill B.J. Tracking euxinia in the ancient acean: a multiproxy perspective and Proterozoic case study. Annual Review of Earth and Planetary Sciences 2009, 37:507-534.
60. Marshall C.P., Javaux E.J., Knoll A.H., Walter M.R. Combined micro-Fourier transform infrared (FTIR) spectroscopy and micro-Raman spectroscopy of Proterozoic acritarchs: a new approach to Palaeobiology. Precambrian Research 2005, 138:208-224.
61. Marshall C.P., Love G.D., Snape C.E., Hill A.C., Allwood A.C., Walter M.R., Van Kranendonk M.J., Bowden S.A., Sylva S.P., Summons R.E. Structural characterization of kerogen in 3.4Ga Archaean cherts from the Pilbara Craton, Western Australia. Precambrian Research 2007, 155:1-23.
62. Marynowski L., Czechowski F., Simoneit B.R.T. Phenylnaphthalenes and polyphenyls in Palaeozoic source rocks of the Holy Cross Mountains, Poland. Organic Geochemistry 2001, 32:69-85.
63. Moldowan J.M., Talyzina N.M. Biogeochemical evidence for dinoflagellate ancestors in the Early Cambrian. Science 1998, 281:1168-1170.
64. Moreau R.A., Powell M.J., Fett W.F., Whitaker B.D. The effect of ethanol and oxygen on the growth of Zymomonas mobilis and the levels of hopanoids and other membrane lipids. Current Microbiology 1997, 35:124-128.
65. Mycke B., Michaelis W., Degens E.T. Biomarkers in sedimentary sulfides of Precambrian age. Organic Geochemistry 1988, 13:619-625.
66. Ohkouchi N., Nakajima Y., Okada H., Ogawa N.O., Suga H., Oguri K., Kitazato H. Biogeochemical processes in the saline meromictic Lake Kaiike, Japan: implications from molecular isotopic evidences of photosynthetic pigments. Environmental Microbiology 2005, 7:1009-1016.
67. Pearson A., Flood Page S.R., Jorgenson T.L., Fischer W.W., Higgins M.B. Novel hopanoid cyclases from the environment. Environmental Microbiology 2007, 9:2175-2180.
68. Peters K.E., Moldowan J.M. The Biomarker Guide-Interpreting Molecular Fossils in Petroleum and Ancient Sediments 1993, Prentice Hall, Englewood Cliffs, New Jersey, p. 363.
69. Peters K.E., Walters C.C., Moldowan J.M. The Biomarker Guide: Biomarkers and Isotopes in Petroleum Exploration and Earth History 2004, vol. 1. The Press Syndicate of the University of Cambridge, Cambridge.
70. Peters K.E., Walters C.C., Moldowan J.M. The Biomarker Guide: Biomarkers and Isotopes in the Environment and Human History 2004, vol. 2. The Press Syndicate of the University of Cambridge, Cambridge.
71. Pratt L.M., Summons R.E., Hieshima G.B. Sterane and triterpane biomarkers in the Precambrian Nonesuch Formation, North American Midcontinent Rift. Geochimica et Cosmochimica Acta 1991, 55:911-916.
72. Pruss S.B., Bosak T., Macdonald F.A., McLane M., Hoffman P.F. Microbial facies in a Sturtian cap carbonate, the Rasthof Formation, Otavi Group, northern Namibia. Precambrian Research 2010, 181:187-198.
73. Radke M., Welte D.H. The Methylphenanthrene Index (MPI): a maturity parameter based on aromatic hydrocarbons. Advances in Organic Geochemistry 1983, 1981:504-512.
74. Raiswell R., Fisher Q.J. Mudrock-hosted carbonate concretions: a review of growth mechanisms and their influence on chemical and isotopic composition. Journal of the Geological Society, London 2000, 157:239-251.
75. Rashby S.E., Sessions A.L., Summons R.E., Newman D.K. Biosynthesis of 2-methylbacteriohopanepolyols by an anoxygenic phototroph. Proceedings of the National Academy of Sciences 2007, 104:15099-21510.
76. Rasmussen B., Fletcher I.R., Brocks J.J., Kilburn M.R. Reassessing the first appearance of eukaryotes and cyanobacteria. Nature 2008, 455:1101-1104.
77. Reitner J., Peckmann J., Reimer A., Schumann G., Thiel V. Methane-derived carbonate build-ups and associated microbial communities at cold seeps on the lower Crimean shelf (Black Sea). Facies 2005, 51:71-84.
78. Rohmer M., Bouvier-Navé P., Ourisson G. Distribution of hopanoid triterpenes in prokaryotes. Journal of General Microbiology 1984, 130:1137-1150.
79. Rooney A.D., Selby D., Houzay J.-P., Renne P.R. Re-Os geochronology of a Mesoproterozoic sedimenatary succession, Taoudeni basin, Mauritania: implications for basin-wide correlation and Re-Os organic rich sediments systematics. Earth and Planetary Science Letters 2010, 289:486-496.
80. Sakata S., Hayes J.M., McTaggart A.R., Evans R.A., Leckrone K.J., Togasaki R.K. Carbon isotopic fractionation associated with lipid biosynthesis by a cyanobacterium: relevance for interpretation of biomarker records. Geochimica et Cosmochimica Acta 1997, 61:5379-53889.
81. Sánchez-Beristain F., Schäfer N., Simon K., Reitner J. New geochemical method to characterise mirobialites from the St. Cassian Formation, Dolomites, Northeastern Italy. Lecture Notes in Earth Sciences 2010, 131:435-453.
82. Schaeffer P., Adam P., Wehrung P., Albrecht A. Novel aromatic carotenoid derivatives from sulfur photosynthetic bacteria in sediments. Tetrahedron Letters 1997, 38:8413-8416.
83. Schidlowski M., Gorzawksi H., Dor I.A. Carbon isotope variations in a solar pond microbial mat: role of environmental gradients as steering variables. Geochimica et Cosmochimica Acta 1994, 58:2289-2298.
84. Schwark L., Frimmel A. Chemostratigraphy of the Posidonia Black Shale, SW-Germany II. Assessment of extent and persistence of photic-zone anoxia using aryl isoprenoid distributions. Chemical Geology 2004, 206:231-248.
85. Seifert W.K., Michael Moldowan J. Applications of steranes, terpanes and monoaromatics to the maturation, migration and source of crude oils. Geochimica et Cosmochimica Acta 1978, 42:77-95.
86. Shen Y., Canfield D.E., Knoll A.H. Middle Proterozoic ocean chemistry: evidence from the McArthur Basin, northern Australia. American Journal of Science 2002, 302:81-109.
87. Sinninghe Damste J.S., Schouten S., van Duin A.C.T. Isorenieratene derivatives in sediments: possible controls on their distribution. Geochimica et Cosmochimica Acta 2001, 65:1557-1571.
88. Staal M., Thar R., Kühl M., van Loosdrecht M.C.M., Wolf G., de Brouwer J.F.C., Rijstenbil J.W. Different carbon isotope fractionation patterns during the development of phototrophic freshwater and marine biofilms. Biogeosciences 2007, 4:613-626.
89. Summons R.E., Brassell S.C., Eglinton G., Evans E., Horodyski R.J., Robinson N., Ward D.M. Distinctive hydrocarbon biomarkers from fossiliferous sediment of the Late Proterozoic Walcott Member, Chuar Group, Grand Canyon, Arizona. Geochimica et Cosmochimica Acta 1988, 52:2625-2637.
90. Summons R.E., Jahnke L.L., Hope J.M., Logan G.A. 2-Methylhopanoids as biomarkers for cyanobacterial oxygenic photosynthesis. Nature 1999, 400:554-557.
91. Summons R.E., Powell T.G., Boreham C.J. Petroleum geology and geochemistry of the Middle Proterozoic McArthur Basin, Northern Australia. III. Composition of extractable hydrocarbons. Geochimica et Cosmochimica Acta 1988, 52:1747-1763.
92. Summons R.E., Powell T.G. Identification of aryl isoprenoids in source rocks and crude oils: biological markers for the green sulphur bacteria. Geochimica et Cosmochimica Acta 1987, 51:557-566.
93. Summons R.E., Volkman J.K., Boreham C.J. Dinosterane and other steroidal hydrocarbons of dinoflagellate origin in sediments and petroleum. Geochimica et Cosmochimica Acta 1987, 51:3075-3082.
94. Talbot H.M., Summons R.E., Jahnke L.L., Cockell C.S., Rohmer M., Farrimond P. Cyanobacterial bacteriohopanepolyol signatures from cultures and natural environmental settings. Organic Geochemistry 2008, 39:232-263.
95. Teal D.A.J., Kah L.C., 2005. Using C-isotopes to Constrain Intrabasinal Stratigraphic Correlations: Mesoproterozoic Atar Group, Mauritania, Geological Society of America (GSA), p. 45.
96. ten Haven H.L., De Leeuw J.W., Rullkötter J., Sinninghe Damste J.S. Restricted utility of the pristane/phytane ratio as a palaeoenvironmental indicator. Nature 1987, 330:641-643.
97. Thompson K.F.M. Fractionated aromatic petroleums and the generation of gas-condensates. Organic Geochemistry 1987, 11:573-590.
98. Waldbauer J.R., Sherman L.S., Sumner D.Y., Summons R.E. Late Archean molecular fossils from the Transvaal Supergroup record the antiquity of microbial diversity and aerobiosis. Precambrian Research 2009, 169:28-47.
99. Welander P.V., Coleman M.L., Sessions A.L., Summons R.E., Newman D.K. Identification of a methylase required for 2-methylhopanoid production and implications for the interpretation of sedimentary hopanes. Proceedings of the National Academy of Sciences 2010, 107:8537-8854.
100. Welander P.V., Hunter R.C., Zhang L., Sessions A.L., Summons R.E., Newman D.K. Hopanoids play a role in membrane integrity and pH homeostasis in Rhodopseudomonas palustris TIE-1. Journal of Bacteriology. 2009, 191:6145-6156.
101. Wieland A., Pape T., Möbius J., Klock J.H., Michaelis W. Carbon pools and isotopic trends in a hypersaline cyanobacterial mat. Geobiology 2008, 6:171-186.
102. 2 fixation and implications for the Precambrian nitrogen cycle. Geobiology 2006, 4:285-297.
103. Zundel M., Rohmer M. Prokaryotic triterpenoids. 3. The biosynthesis of 2b-methylhopanoids and 3b-methylhopanoids of Methylobacterium organophilum and Acetobacter pasteurianus ssp. pasteurianus. European Journal of Biochemistry 1985, 150:35-39.