Mississippian δ13Ccarb and conodont apatite δ18O records - Their relation to the Late Palaeozoic Glaciation

Palaeogeography, Palaeoclimatology, Palaeoecology

Volumn 268, Issue 3-4, 2008, Pages 273-292

  Buggisch, Werner ^a   Joachimski, Michael M ^a   Sevastopulo, George ^b   Morrow, Jared R ^c  

^a UNIVERSITY OF ERLANGEN NUREMBERG   (Germany)

^b TRINITY COLLEGE DUBLIN   (Ireland)

^c SAN DIEGO STATE UNIVERSITY   (United States)

Author keywords

13C; 18O; Apatite; Glaciation; Mississippian; Palaeotemperature

Indexed keywords

APATITE; CARBON CYCLE; CARBON ISOTOPE; CARBONATE; CLIMATE CHANGE; CONODONT; COOLING; DEVONIAN; GLACIATION; LAURENTIA; MISSISSIPPIAN; OXYGEN ISOTOPE; PALEOTEMPERATURE; PALEOZOIC; PENNSYLVANIAN; RECONSTRUCTION; ROCK; SERPUKHOVIAN; TOURNAISIAN;

EURASIA; EUROPE;

EID: 53049104612     PISSN: 00310182     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.palaeo.2008.03.043     Document Type: Article

References (101)

1. Alekseev A.A., Lebedev O.A., Barskova M.I., Kononova L.I., and Chizhova V.A. On the stratigraphic position of the Famennian and Tournaisian fossil vertebrate beds in Andreyevka, Tula region, Central Russia. Proc. Geol. Assoc. 105 (1994) 41-52
2. Arthur M.A., Dean W.E., and Prall L.M. Geochemical and climatic effects of increased marine organic carbon burial at the Cenomanian/Turonian boundary. Nature 335 (1988) 714-717
3. Austin R.L., and Davis R.B. Problems of recognition and implications of Dinantian conodont biofacies of British Iles. Geol. Soc. Amer. Spec. Pap. 196 (1984) 195-228
4. Banner J.L., and Kaufmann J. The isotopic record of ocean chemistry and diagenesis preserved in non-luminescent brachiopods from Mississippian carbonate rocks, Illinois and Missouri. Geol. Soc. Amer Bull. 106 (1994) 1074-1082
5. Belka Z. Lower Carboniferous conodont biostratigraphy in the north-eastern part of the Moravia-Silesia Basin. Acta Geol. Pol. 35 (1985) 33-60
6. Belka Z., and Groessens M. Conodont succession across the Tournaisian-Visean Boundary beds at Salet, Belgium. Bull. Soc. Bel. Géol. 95 (1986) 257-280
7. Belka Z., and Korn D. Re-evaluation of the Early Carboniferous conodont succession in the Esla area of the Cantabrian Zone (Cantabrian Mountains, Spain). Courier Forsch. Senck. 168 (1994) 183-193
8. Bender H., Herbig H.-G., Gursky H.-J., and Amler M.R.W. Exkursionen A2 und B2. Beckensedimente im Oberdevon und Unterkarbon des östlichen Rheinischen Schiefergebirges - Fazies, Paläogeographie und Meeresspiegelschwankungen. Geol. Palaeontol. 27 (1993) 332-355
9. Bouckaert J., Conil R., Groessens E., Streel M., and Sandberg C. Excursion C. In: Bouckaert J., and Streel. M. (Eds). Guidebook International Symposium on Namurian 1974. Ministry of Economis Affairs, ADM Mines, Geological Survey of Belgium, Brussels (1974) 1-16
10. Brenckle P.L. Hidden Valley locality. In: Brenckle P.L., and Page W.R. (Eds). Palaeoforams +//0-97, Guidebook Post Conference Field Trim Arrow Canyon Range, Southern Nevada, U.S.A.. Cushman Foundation Foraminiferal Research. Suppl. Spec. Publ. vol. 36 (1997) 57-63
11. Brenckle P.L. Battleship Wash section. In: Brenckle P.L., and Page W.R. (Eds). Palaeoforams '97 Guidebook Post conference field trim Arrow Canyon Range, Southern Nevada, U.S.A. Cushman Foundation Foraminiferal research. Suppl. Spec. Publ. vol. 36 (1997) 45-53
12. Brenckle P.L., Baesemann J.F., Lane H.R., West R.R., Webster G.D., Langenheim R.L., Brand U., and Richards B.C. Arrow Canyon, the Mid-Carboniferous Boundary stratotype. In: Brenckle P.L., and Page W.R. (Eds). Palaeoforams '97 Guidebook Post conference field trim Arrow Canyon Range, Southern Nevada, U.S.A. Cushman Foundation Foraminiferal research. Suppl. Spec. Public. vol. 36 (1997) 13-32
13. Brezinski, D.K., 2006. Palaeoclimatic implications of Late Devonian glacial deposits from the eastern United States. http://gsa.confex.com/gsa/2006AM/finalprogram/abstract_114087.htm.
14. Bruckschen P., Oesmann S., and Veizer J. Isotope stratigraphy of the European Carboniferous: proxy signals for ocean chemistry, climate and tectonics. Chem. Geol. 161 (1999) 127-163
15. Bruckschen P., Veizer J., Schwark L., and Leythaeuser D. Isotope stratigraphy for the transition from the late Palaeozoic greenhouse in the Permo-Carboniferous icehouse - new results. Terra Nostra 4 (2001) 7-11
16. Buggisch W., and Haas S. Early Carboniferous (Mississippian) carbon isotope stratigraphy of Laurentia and Europe. Geol. Soc. Am. 32 7 (2000) 277 Abstracts with Programs
17. Buggisch W., and Joachimski M.M. Carbon isotope stratigraphy of the Devonian of Central and Southern Europe. Palaeogeo. Palaeoclimat. Palaeoecol. 240 (2006) 68-88
18. Caputo M.V. Late Devonian glaciation in South America. Palaeogeo., Palaeoclimat., Palaeoecol. 51 (1985) 291-317
19. Caputo M.V., and Crowell J.C. Migration of glacial centers across Gondwana during Paleozoic Era. Geol. Soc. Am. Bull. 96 (1985) 1020-1036
20. Casier J.-G., Mamet B., Préat A., and Sandberg C.A. Sedimentology, conodonts and ostracods of the Devonian-Carboniferous strata of Anseremme railway bridge section, Dinant Basin, Belgium. Bull. Inst. Royal Sci. Natur. Belgique, Sci. Terre 74 (2004) 45-68
21. Conil R., and Groessens E. Excursion B. In: Bouckaert J., and Streel. M. (Eds). Guidebook. International Symposium on Namurian 1974. Ministry of Economics Affairs, ADM Mines, Geol. Surv. Belg. Brussels (1974) 1-26
22. Crowell J.C. Pre-Mesozoic ice ages: their bearing on understanding the climate system. Geol. Soc. Am. Mem. 192 (1999) 106 pp
23. Crowley T.J., and Baum S.K. Modeling late Paleozoic glaciation. Geology 20 (1992) 507-510
24. Cygan C., and Perret M.F. Conodonts from the Upper Devonian-Lower Carboniferous succession of Milles (Arize Massif). Pyrenees fieldtrip, Guidebook, ECOS VIII, France-Spain (2002) 88 pp.
25. Elrick M., and Read J.F. Cyclic ramp-to-basin carbonate deposits, Lower Mississippian, Wyoming and Montana: a combined field and computer modeling study. J. Sediment. Petrol. 61 (1991) 1194-1224
26. Feist R. The Palaeozoic of the Montagne Noire, Southern France. Guidebook of the Field excursion, ECOS VIII: 8th European Conodont Symposium (2002) 82 pp.
27. Feist R., Flajs G., and Girard C. The stratotype section of the Devonian-Carboniferous boundary. Cour. Forschungsinst. Senckenberg 225 (2000) 77-82
28. Flajs G., and Feist R. Index conodonts, trilobites and environment of the Devonian-Carboniferous boundary beds at Serre (Montagne Noire, France). Cour. Forschungsinst. Senckenberg 100 (1988) 53-107
29. Frakes L.A., Francis J.E., and Syktu J.I. Climate Modes of the Phanerozoic (1992), Cambridge University Press 274 pp.
30. García-López S., and Sanz-López J. A stratigraphic overview of the Cantabrian Devonian (NW Spain). In: García-López S., and Bastida F. (Eds). Palaeozoic Conodonts from Northern Spain, ECOS VIII. Cuadernos del Museo Geominero vol. 1 (2002) 51-59
31. García-López S., and Sanz-López J. Devonian to Lower Carboniferous conodont biostratigraphy of the Bernesga Vally section (Cantabrian Zone, NW Spain). In: García-López S., and Bastida F. (Eds). Palaeozoic Conodonts from Northern Spain, ECOS VIII. Cuadernos del Museo Geominero vol. 1 (2002) 163-206
32. Garzanti E., and Sciunnach D. Early Carboniferous onset of Gondwanian glaciation and Neo-tethyan rifting in South Tibet. Earth Planet. Sci. Lett. 148 (1997) 359-365
33. Girard C. Conodont biofacies and event stratigraphy across the D/C boundary in the stratotype area (Montagne Noire, France). Cour. Forschungsinst. Senckenberg 168 (1994) 299-309
34. González-Bonorino G. Carboniferous glaciation in Gondwana. Evidence for grounded marine ice and continental glaciation in southwestern Argentina. Palaeogeogr., Palaeoclimat., Palaeoecol. 91 (1992) 363-375
35. González-Bonorino G., and Eyles N. Inverse relation between ice extent and the late Paleozoic glacial record of Gondwana. Geology 23 (1995) 1015-1018
36. Gregory R.T. Oxygen isotope history of seawater revisited: timescales for boundary event changes in oxygen isotope composition of seawater. In: Taylor H.P., O'Neil J.R., and Kaplan I.R. (Eds). Stable Isotope Geochemistry: A tribute to Samuel Epstein. Geochem. Soc. Spec. Publ. vol. 3 (1991) 65-76
37. Groessens E. Distribution de conodontes dans le Dinantien de la Belgique. International Symposium on Belgian Micropalaeontological limits from Emsian to Visean Namur 1974. Geol. Surv. Belgium Publication vol. 17 (1975) 1-193
38. Grossman E.L., Mii H.-S., and Yancey T.E. Stable isotopes in late Pennsylvanian brachiopods from the United States: Implications for Carboniferous paleoceanography. Geol. Soc. Am. Bull. 105 (1993) 1285-1296
39. Grossman E.L., Yancey T.e., Jones T.E., Bruckschen P., Chuvashov B., Mazullo S.J., and Mii H.-S. Glaciation, aridification, and carbon sequestration in the Permo-Carboniferous: the isotopic record for low latitudes. Palaeogeogr., Palaeoclimat., Palaeoecol. 268 (2008) 222-233 10.1016/j.palaeo.2008.03.053 (this volume)
40. Gutschick R.C., and Sandberg C.A. Mississippian continental margins of the conterminous United States. In: Stanley D.J., and Moore G.T. (Eds). The shelfbreak margin-critical interface on continental margins. Soc. Econo. Paleont. Min., Spec. Publ. vol. 33 (1983) 79-96
41. Hance L., Devuyst F.-X., and Poty E. Sequence stratigraphy of the Belgian Lower Carboniferous - tentative correlation with the British Iles. In: Hills L.V., Henderson C.M., and Bamber E.W. (Eds). Carboniferous and Permian of the World. Can. Soc. Petrol. Geol. Mem vol. 19 (2002) 41-51
42. Higgins A.C. Conodont zonation of the late Visean-early Westphalian strata of south and central Pennines of northern England. Geol. Surv. Great Brit. Bull 53 (1975) 1-90
43. Iacumin P., Bocherens H., Mariotti A., and Longinelli A. Oxygen isotope analysis of co-existing carbonate and phosphate in biogenic apatite: a way to monitor diagenetic alteration of bone phosphate?. Earth Planet. Sci. Lett. 142 (1996) 1-6
44. Isaacson P.E., and Diaz-Martinez E. Evidence of middle-late Paleozoic foreland basin and significant latitude shift, Central Andes. Am. Assoc. Petrol. Geol. Mem. 62 (1995) 231-249
45. Isbell J.L., Miller M.F., Wolfe K.L., and Lenaker P.A. Timing of late Paleozoic glaciation in Gondwana: was glaciation responsible for the development of northern hemisphere cyclothems?. In: Cham M.A., and Archer A.W. (Eds). Extreme Depositional Environments: Mega End Members in Geological Time. Geol. Soc. Amer. Spec. Paper vol. 370 (2003) 5-24
46. 18O signatures indicate climatic cooling as a trigger of the Late Devonian (F-F) mass extinction. Geology 30 (2002) 711-714
47. Joachimski M.M., van Geldern R., Breisig. S., Day J., and Buggisch W. Oxygen isotope evolution of biogenic calcite and apatite during the Middle and Upper Devonian. Int. J. Earth Sci. 93 (2004) 542-553
48. Joachimski M.M., von Bitter P.H., and Buggisch W. Constraints on Pennsylvanian glacioeustatic sea-level changes using oxygen isotopes of conodont apatite. Geology 34 (2006) 277-280
49. Johnston I.S., and Higgins A.C. Conodont faunas from the Lower Carboniferous rocks at Hook Head, County Wexford. J. Earth Sci. R. Dubl. Soc. 4 (1981) 83-96
50. Kaiser, S.I., 2005. Mass extinctions, climatic and oceanographic changes at the Devonian/Carboniferous boundary. Thesis Ruhr-Universität Bochum, http://www-brs.ub.ruhr-uni-bochum.de/netahtml/HSS/Diss/KaiserSandraIsabe lla/diss.pdf.
51. Kaiser S.I., Steuber T., Becker R.T., and Joachimski M.M. Geochemical evidence for major environmental change at the Devonian-Carboniferous boundary mass-extinction. Palaeogeo., Palaeoclimat. Palaeoecol. 240 (2006) 146-160
52. Kolodny Y., Luz B., and Navon A. Oxygen isotope variations in phosphate of biogenic apatites, I. Fish bone apatite - rechecking the rules of the game. Earth Planet. Sci. Lett. 64 (1983) 398-404
53. Korn D., and Weyer D. High resolution stratigraphy of the Devonian-Carboniferous transitional beds in the Rhenish Mountains. Mitt. Mus. Naturkunde Berlin, Geowiss. Reihe 6 (2003) 79-124
54. Kump L. Interpreting carbon-isotope excursions: strangelove oceans. Geology 19 (1991) 299-302
55. Kump L., and Arthur M.A. Interpreting carbon isotope excursions: carbonate and organic matter. Chem. Geol. 161 (1999) 181-198
56. Lea D.W., Martin P.A., Pak D.K., and Spero H.J. Reconstructing a 350 ky history of sea level using planktonic Mg/Ca and oxygen isotope records from a Cocos Ridge core. Quat. Sci. Rev. 21 (2002) 283-293
57. Lethiers F., and Feist R. Ostracodes, stratigraphie et bathymétrie du passage Dévonien-Carbonifère au Viséen inférieur en Montagne Noire (France). Geobios 24 (1991) 71-104
58. Limarino C., and Gutierrez P. Diamictites in the Agua Colorada Formation (northwestern Argentina): new evidence of Carboniferous glaciation in South America. J. South Am. Earth Sci. 3 (1990) 9-20
59. 18O record of Phanerozoic abiotic marine calcite cements. Geophys. Res. Lett. 16 (1989) 319-322
60. López-Gamundi O.R. Glacial-postglacial transition in the Late Palaeozoic basins of South America. In: Martini I.P. (Ed). Late Glacial and Postglacial Environmental Changes - Quarternary, Carboniferous-Permian, and Proterozoic (1997), Oxford University Press, New York 147-168
61. López-Gamundi O.R., and Martínez M. Evidence of glacial abrasion in the Calingasta-Uspallata and western Paganzo basins, mid-Carboniferous of western Argentina. Palaeogeo., Palaeoclimat. Palaeoecol. 159 (2000) 145-165
62. Mii H., Grossman E.L., and Yancey T.E. Carboniferous isotope stratigraphies of North America: implications for Carboniferous paleoceanography and Mississippian glaciation. Geol. Soc. Am. Bull. 111 (1999) 960-973
63. Mii H., Grossman E.L., Yancey T.E., Chuvashov B., and Egorov A. Isotope records of brachiopod shells from the Russian platform: evidence for the onset of mid-Carboniferous glaciation. Chem. Geol. 175 (2001) 133-147
64. Miller D.J., and Eriksson K.A. Sequence stratigraphy of Upper Mississippian strata in the Central Appalachians: a record of glacioeustasy and tectonoeustasy in a foreland basin setting. Am. Assoc. Petrol. Geol. Bull. 84 (2000) 210-233
65. Morrow J.R., and Webster G.D. Carbonate microfacies and related conodont biofacies, Mississippian-Pennsylvanian boundary strata, Granite Mountain, West Central Utah. Bingham Young University Studies 37 (1991) 99-124
66. Muchez P., Hou H., Groessens E., Hance L., and Tan Z. Sedimentation and Palaeogeography of the Famennian, Tournaisian and Lower Visean in South China. Mém. Inst. Géol. Univ. Louvain 36 (1996) 175-191
67. Muehlenbachs K. The oxygen isotopic composition of the oceans, sediments and the seafloor. Chem. Geol. 145 (1998) 263-273
68. Nöth S. Conodont color (CAI) versus microcrystalline and textural changes in Upper Triassic conodonts from Northwest Germany. Facies 38 (1998) 165-173
69. O'Neil J.R., Roe J.L., Reinhardt E., and Blake R.E. A rapid and precise method of oxygen isotope analysis of biogenic phosphate. Isr. J. Earth Sci. 43 (1994) 203-212
70. Page W.R., and Dixon G.L. Geologic framework of the Arrow Canyon area, Clark County, Nevada. In: Brenckle P.L., and Page W.R. (Eds). Palaeoforams '97 Guidebook, Post Conference Field Trip Arrow Canyon Range, Southern Nevada, U.S.A. Cushman Foundation Foraminiferal Research. Spec. Publ. Suppl. vol. 36 (1997) 45-53
71. Poole F.G., and Sandberg C.A. Mississippian paleogeography and conodont biostratigraphy of the western United States. In: Cooper J.D., and Stevens G.H. (Eds). Paleozoic Paleogeography of the Western United States. Pacific Sestion. Soc. Econ. Paleont. Min., Spec. Publ. vol. 42 (1991) 109-124
72. Popp B.N., Anderson T.F., and Sandberg P.A. Brachiopods as indicators of original isotopic compositions in some Paleozoic limestones. Geol. Soc. Am. Bull. 97 (1986) 1262-1269
73. Richards B.C., Barclay J.E., Bryan D., Hartling A., Henderson C.M., and Hinds R.C. Chapter 14 - Carboniferous strata of Western Canada Basin. In: Mossop G.D., and Shetson I. (Eds). Geological Atlas of Western Canada Basin. Can. Soc. Petrol. Geol. (1994), Alberta Research Council, Calgary 221-250
74. Romanek C.S., Grossman E.L., and Morse J.W. Carbon isotopic fractionation in synthetic aragonite and calcite: effects of temperature and precipitation rate. Geochim. Cosmochim. Acta 56 (1992) 419-430
75. Ross C.A., and Ross J.R.P. Late Paleozoic sea level and depositional sequences. Cushman Foundation for Foraminiferal Research 24 (1987) 137-149 Spec. Publ.
76. Saltzman M.R. Carbon and oxygen isotope stratigraphy of the lower Mississippian (Kinderhookian-Lower Osagean), Western United States; implications for seawater chemistry and glaciation. Geol. Soc. Am. Bull. 114 (2002) 96-108
77. 2?. Geology 31 (2003) 151-154
78. Saltzman M.R. Organic carbon burial and phosphogenesis in the Antler Foreland Basin; an out-of-phase relationship during the Lower Mississippian. J. Sediment. Res. 73 (2003) 844-855
79. Saltzman M.R., Gonzalez L.A., and Lohmann K.C. Earliest Carboniferous cooling step triggered by the Antler Orogeny?. Geology 28 (2000) 347-350
80. 13C; an example from the lower Mississippian. Palaeogeo., Palaeoclimat., Palaeoecol. 213 (2004) 359-377
81. Sánchez de Posada L.C., Martínez Chacón M.L., Villa E., and Méndez C.A. The Carboniferous succession of the Asturian-Leonese Domain. An overview. In: García-López S., and Bastida F. (Eds). Palaeozoic Conodonts from Northern Spain, ECOS VIII. Cuadernos del Museo Geominero vol. 1 (2002) 61-91
82. Sandberg C.A., Ziegler W., Leuteritz K., and Brill M.S. Phylogeny, specification, and zonation of Siphonodella (Conodonta, Upper Devonian, Lower Carboniferous). Newsletter on Stratigraphy 7 (1978) 102-120
83. Sandberg C.A., Poole F.G., and Johnson J.G. Upper Devonian of the Western United States. In: McMillan N.J., et al. (Ed). Devonian of the World. Proceedings of the Canadian Society of Petrology and Geology International Symposium. Devonian System Memoir vol. 14 (1988) 183-220
84. Savin S.M. The history of the earth's surface temperature during the past 100 million years. Ann. Rev. Earth. Planet. Sci. 5 (1977) 319-355
85. Savoy L.E., Harris A.G., and Montjoy E.W. Extension of lithofacies and conodont biofacies models of Late Devonian to Early Carboniferous carbonate ramp and black shale systems, southern Canadian Rocky Mountains. Can. J. Earth Sci. 36 (1999) 1281-1298
86. Scotese C.R. Paleogegraphic Atlas, Paleomap Progress Report 90-0497 (1997), Department of Geology, University of Texas at Airlington, Airlington, Texas 37 pp.
87. Shackleton N.J., and Kennett J.P. Paleotemperature history of the Cenozoic and the initiation of Antarctic glaciation: oxygen and carbon analyses in DSDP sites 277, 279 and 281. Initial Rep. Deep Sea Drill. Proj. 29 (1975) 743-755
88. Siegmund H., Trappe J., and Oschmann W. Sequence stratigraphic and genetic aspects of the Tournaisian "Liegender Alaunschiefer" and adjacent beds. Int. J. Earth. Sci. 91 (2002) 934-949
89. Sleeman A.G., Thornbury B., and Sevastopulo G.D. The stratigraphy of the Courceyan (Carboniferous; Dinantian) Rocks of the Cloyne Syncline, west of Cork Habour. Irish J. Earth Sci. 8 (1986) 21-40
90. Smith Jr. L.B., and Read J.F. Rapid onset of late Paleozoic glaciation on Gondwana: evidence from Upper Mississippian strata of the Midcontinent, United States. Geology 28 (2000) 279-282
91. Stanton Jr. R.J., Jeffrey D.L., and Ahr W.M. Early Mississippian climate based on oxygen isotope compositions of brachiopods, Alamogordo Member of the Lake Valley Formation, south-central New Mexico. Geol. Soc. Am. Bull. 114 (2002) 4-11
92. STG. Stratigraphic Table of Germany 2002 (STG 2002). Published by the German Stratigraphic Commision (2002) 3-00-010197-7
93. Streel M., Caputo M.V., Loboziak S., and Melo J.H.G. Late Frasnian-Famennian climates based on palynomorph analyses and the question of the Late Devonian glaciations. Earth Sci. Rev. 52 (2000) 121-173
94. 13C of periplatform sediments: implications for stratigraphy and the global carbon cycle. Sediment. Geol. 175 (2005) 115-129
95. Van Steenwinkel M. Sedimentation and conodont stratigraphy of the Hastiere Limestone, lowermost Dinantian, Anseremme, Belgium. Rijks Geologische Dienst. Nieuwe 32 (1980) 30-33
96. Veevers J.J. Pangea: evolution of a supercontinent and its consequences for Earth's paleoclimate and sedimentary environments. In: Klein G.D. (Ed). Pangea: Paleoclimate, Tectonics, and Sedimentation during Accretion, Zenith, and Breakup of a Supercontinent. Geol. Soc. Am. Spec. Pap. 288 (1994) 13-23
97. 18O evolution of Phanerozoic seawater. Chem. Geol. 161 (1999) 59-88
98. Walliser O.H. lobal Events in the Devonian and Carboniferous. In: Walliser O.H. (Ed). Global Events and Event Stratigraphy (1996), Springer 225-250
99. 18O of Silurian brachiopods and conodonts. Geochim. Cosmochim. Acta 64 (2000) 1859-1872
100. Wolff T., Mulitza S., Arz H., Pätzold J., and Wefer G. Oxygen isotopes versus CLIMAP (18 ka) temperatures: a comparison from the tropical Atlantic. Geology 26 (1998) 675-678
101. Wright V.P., and Vanstone S.D. Onset of the late Palaeozoic glacio-eustacy and the evolving climates of low latitude areas: a synthesis of current understanding. J. Geol. Soc. (Lond.) 158 (2001) 579-582