U-Pb (zircon) age constraints on the timing and duration of wenlock (Silurian) paleocommunity collapse and recovery during the "Big Crisis"

Bulletin of the Geological Society of America

Volumn 124, Issue 11-12, 2012, Pages 1841-1857

  Cramer, Bradley D ^a,j   Condon, Daniel J ^b   Söderlund, Ulf ^c   Marshall, Carly ^d   Worton, Graham J ^e   Thomas, Alan T ^d   Calner, Mikael ^c   Ray, David C ^f,g   Perrier, Vincent ^h   Boomer, Ian ^d   Patchett, P Jonathan ⁱ   Jeppsson, Lennart ^c  

^a UNIVERSITY OF KANSAS   (United States)

^b BRITISH GEOLOGICAL SURVEY   (United Kingdom)

^c LUND UNIVERSITY   (Sweden)

^d UNIVERSITY OF BIRMINGHAM   (United Kingdom)

^e Dudley Museum and Art Gallery   (United Kingdom)

^f UNIVERSITY OF PORTSMOUTH   (United Kingdom)

^g Neftex Petroleum Consultants Ltd   (United Kingdom)

^h UNIVERSITY OF TARTU   (Estonia)

ⁱ The University of Arizona   (United States)

^j UNIVERSITY OF IOWA   (United States)

more..

Author keywords

[No Author keywords available]

Indexed keywords

AGE CONSTRAINTS; CHEMICAL EVENTS; ENGLAND; GLOBAL CARBON CYCLE; HIGH-PRECISION; ISOTOPE DILUTIONS; PALEOZOIC; RECALIBRATIONS; SILURIAN PERIOD; TIME-SCALES; VOLCANIC ASH; WEIGHTED MEAN;

BENTONITE; CARBON; GEOCHRONOLOGY; ISOTOPES; ZIRCON;

LEAD;

BENTONITE; BIOSTRATIGRAPHY; CARBON CYCLE; PALEOZOIC; TIMESCALE; URANIUM-LEAD DATING; WENLOCKIAN;

ENGLAND; GOTLAND; SWEDEN; UNITED KINGDOM; WEST MIDLANDS;

TROGLODYTINAE;

EID: 84871147827     PISSN: 00167606     EISSN: 19432674     Source Type: Journal    
DOI: 10.1130/B30642.1     Document Type: Article

References (132)

1. André, L., Hertogen, J., and Deutsch, S., 1986, Ordovician- Silurian magmatic provinces in Belgium and the Caledonian orogeny in middle Europe: Geology, v. 14, p. 879-882, doi:10.1130/0091-7613(1986)14<879: OMPIBA>2.0.CO;2.
2. Batchelor, R.A., and Jeppsson, L., 1999, Wenlock metabentonites from Gotland, Sweden: Geochemistry, sources and potential as chemostratigraphic markers: Geological Magazine, v. 136, p. 661-669, doi:10.1017/S001675689900285X.
3. Batchelor, R.A., Harper, D.A.T., and Anderson, T.B., 2003, Geochemistry and potential correlation of Silurian (Telychian) metabentonites from Ireland and SW Scotland: Geological Journal, v. 38, p. 161-174, doi: 10.1002/gj.940.
4. Bergström, S.M., Toprak, F.O., Huff, W.D., and Mundil, R., 2008, Implications of a new, biostratigraphically well-controlled, radio-isotopic age for the lower Telychian Stage of the Llandovery Series (Lower Silurian, Sweden): Episodes, v. 31, p. 309-314.
5. Berry, W.B.N., and Murphy, M.A., 1975, Silurian and Devonian Graptolites of Central Nevada: University of California Publications in Geological Sciences 110, 109 p.
6. Bickert, T., Pätzold, J., Samtleben, C., and Munnecke, A., 1997, Paleoenvironmental changes in the Silurian indi cated by stable isotopes in brachiopod shells from Gotland, Sweden: Geochimica et Cosmochimica Acta, v. 61, p. 2717-2730, doi:10.1016/S0016-7037 (97)00136-1.
7. Borths, M.R., and Ausich, W.I., 2011, Ordovician-Silurian Lilliput crinoids during the end-Ordovician biotic crisis: Swiss Journal of Paleontology, v. 130, p. 7-18, doi:10.1007/s13358-010-0003-2.
8. Butler, A.J., 1939, The stratigraphy of the Wenlock Limestone at Dudley: Quarterly Journal of the Geological Society of London, v. 95, p. 37-74, doi:10.1144/GSL .JGS.1939.065.01-04.04.
9. Calner, M., 2005, Silurian carbonate platforms and extinction events-Ecosystem changes exemplified from Gotland, Sweden: Facies, v. 51, p. 584-591, doi:10.1007/s10347-005-0050-0.
10. Calner, M., 2008, Silurian global events-At the tipping point of climate change, in Elewa, A.M.T., ed., Mass Extinctions: Berlin, Springer-Verlag, p. 21-58.
11. Calner, M., and Jeppsson, L., 2003, Carbonate platform evolution and conodont stratigraphy during the middle Silurian Mulde event, Gotland, Sweden: Geological Magazine, v. 140, p. 173-203, doi:10.1017/S0016756802007070.
12. Calner, M., Kozłowska, A., Masiak, M., and Schmitz, B., 2006a, A shoreline to deep basin correlation chart for the Middle Silurian coupled extinction-stable isotopic event: GFF, v. 128, p. 79-84, doi:10.1080/11035890601282079.
13. Calner, M., Ahlberg, P., Axheimer, N., and Gustavsson, L., 2006b, The first record of Odontopleura ovata (Trilobita) from Scandinavia: Part of a Middle Silurian inter continental shelly benthos mass occurrence: GFF, v. 128, p. 33-37, doi:10.1080/11035890601281033.
14. Carls, P., Slavík, L., and Valenzuela-Ríos, J.I., 2007, Revisions of conodont biostratigraphy across the Silurian-Devonian boundary: Bulletin of Geosciences, v. 82, p. 145-164, doi:10.3140/bull.geosci.2007.02.145.
15. Cave, R., and Loydell, D.K., 1998, Wenlock volcanism in the Welsh Basin: Geological Journal, v. 33, p. 107-120, doi:10.1002/(SICI)1099-1034(1998040)33:2<107:: AID-GJ778>3.0.CO;2-R.
16. Cocks, L.R.M., and Torsvik, T.H., 2002, Earth geography from 500 to 400 million years ago; a faunal and palaeomagnetic review: Journal of the Geological Society of London, v. 159, p. 631-644, doi:10.1144/0016-764901-118.
17. Cocks, L.R.M., and Torsvik, T.H., 2005, Baltica from the late Precambrian to mid-Palaeozoic times: The gain and loss of a terrane's identity: Earth-Science Reviews, v. 72, p. 39-66, doi:10.1016/j.earscirev.2005.04.001.
18. Condon, D., Schoene, B., Bowring, S., Parrish, R., McLean, N., Noble, S., and Crowley, Q., 2007, EARTHTIME: Isotopic tracers and optimized solutions for highprecision U-Pb ID-TIMS geochronology: Eos (Transactions, American Geophysical Union), v. 88, no. 52, abstract V41E-06.
19. Cooper, R.A., and Sadler, P.M., 2004, The Ordovician Period, in Gradstein, F.M., Ogg, J.G., and Smith, A.G., eds., A Geologic Timescale 2004: Cambridge, UK, Cambridge University Press, p. 165-187.
20. Corfield, R.M., Siveter, D.J., Cartlidge, J.E., and McKerrow, W.S., 1992, Carbon isotope excursion near the Wenlock-Ludlow (Silurian) boundary in the Anglo-Welsh area: Geology, v. 20, p. 371-374, doi:10.1130/0091-7613(1992)020<0371:CIENTW>2.3.CO;2.
21. 13Ccarb) excursion in North America: GFF, v. 128, p. 85-90, doi:10.1080/11035890601282085.
22. 13Ccarb) biochemostratigraphy across the Llandovery-Wenlock boundary: Is a unified Phanerozoic timescale achievable?: Geological Society of America Bulletin, v. 122, p. 1700-1716, doi:10.1130/B26602.1.
23. Cramer, B.D., Kleffner, M.A., Brett, C.E., McLaughlin, P.I., Jeppsson, L., Munnecke, A., and Samtleben, C., 2010b, Paleobiogeography, high-resolution stratigraphy and the future of Paleozoic biostratigraphy: Fine-scale diachroneity of the Wenlock (Silurian) conodont Kockelella walliseri: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 294, p. 232-241, doi:10.1016/j.palaeo.2010 .01.002.
24. 13Ccarb chemostratigraphy: Lethaia, v. 44, p. 185-202, doi:10.1111/j.1502-3931.2010.00234.x.
25. Cramer, B.D., Munnecke, A., Schofield, D.I., Haase, K.M., and Haase-Schramm, A., 2011b, A revised 87Sr/86Sr curve for the Silurian: Implications for global ocean chemistry and the Silurian timescale: The Journal of Geology, v. 119, p. 335-349, doi:10.1086/660117.
26. Cutler, A., Oliver, P.G., and Reid, C.G.R., 1990, Wren's Nest National Nature Reserve-Geological Handbook and Field Guide: Dudley, England: Dudley Metropolitan Borough Council Leisure Services Department and Nature Conservancy Council, 29 p.
27. Dewey, J.F., and Strachan, R.A., 2003, Changing Silurian-Devonian relative plate motion in the Caledonides: Sinistral transpression to sinistral transtension: Journal of the Geological Society of London, v. 160, p. 219-229, doi:10.1144/0016-764902-085.
28. Eriksson, M.E., and Calner, M., eds., 2005, The Dynamic Silurian Earth: Sveriges Geologiska Undersökning Rapporter och Meddelanden 121, 99 p.
29. Fleischer, M., and Altschuler, Z.S., 1986, The lanthanides and yttrium in minerals of the apatite group: An analysis of available data: Neues Jahrbuch für Mineralogie-Monatshefte, v. 10, p. 467-480.
30. Fortey, N.J., Merriman, R.J., and Huff, W.D., 1995, Silurian and Late Ordovician K-bentonites as a record of late Caledonian volcanism in the British Isles: Transactions of the Royal Society of Edinburgh-Earth Sciences, v. 86, p. 167-180, doi:10.1017/S0263593300002212.
31. Gerstenberger, H., and Haase, G., 1997, A highly effective emitter substance for mass spectrometric Pb isotope ratio determinations: Chemical Geology, v. 136, no. 3-4, p. 309, doi:10.1016/S0009-2541(96)00033-2.
32. Gradstein, F.M., Ogg., J.G., and Smith, A.G., eds., 2004, A Geologic Time Scale 2004: Cambridge, UK, Cambridge University Press, 589 p.
33. Harries, P.J., 1993, Dynamics of survival following the Cenomanian-Turonian mass extinction event: Cretaceous Research, v. 14, p. 563-583, doi:10.1006/cres.1993 .1040.
34. Harries, P.J., and Little, C.T.S., 1999, The early Toarchian (Early Jurassic) and the Cenomanian-Turonian (Late Cretaceous) mass extinctions: Similarities and contrasts: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 154, p. 39-66, doi:10.1016/S0031-0182 (99)00086-3.
35. Harries, P.J., Kauffman, E.G., and Hansen, T.A., 1996, Models for biotic survival following mass extinction, in Hart, M.B., ed., Biotic Recovery from Mass Extinction Events: Geological Society of London Special Publication 102, p. 41-60.
36. Hede, J.E., 1917, Faunan i kalksandstenens märgliga bottenlager söder om Klintehamn på Gotland: Sveriges Geologiska Undersökning, C281, p. 1-32.
37. Hede, J.E., 1928, Berggrunden (Silursystemet), in Munthe, H., Hede, J.E., and Lundquist, G., eds., Beskrivning till kartbladet Slite: Sveriges Geologiska Undersökning, Aa 169, p. 13-65.
38. Hede, J.E., 1942, On the correlation of the Silurian of Gotland: Meddelanden från Lunds Geologisk-Mineralogiska Institution, v. 101, p. 1-25.
39. Hibbard, J.P., 1994, Kinematics of Acadian deformation in the Northern and Newfoundland Appalachians: The Journal of Geology, v. 102, p. 215-228, doi:10.1086/629664.
40. Huff, W.D., Bergström, S.M., and Kolata, D.R., 2000, Silurian K-bentonites of the Dniester Basin, Podolia, Ukraine: Journal of the Geological Society of London, v. 157, p. 493-504, doi:10.1144/jgs.157.2.493.
41. Hutton, D.H.W., 1987, Strike-slip terranes and a model for the evolution of the British and Irish Caledonides: Geological Magazine, v. 124, p. 405-425, doi:10.1017/S0016756800017003.
42. Jaeger, H., 1959, Graptolithen und Stratigraphie des Jüngsten Thüringer Silurs: Abhandlungen der Deutschen Akademie der Wissenschaften zu Berlin, Klasse für Chemie, Geologie und Biologie, v. 2, 197 p.
43. Jaeger, H., 1991, New standard graptolite zonal sequence after the 'Big Crisis' at the Wenlockian/Ludlowian boundary (Silurian): Neues Jahrbuch für Geologie und Palaontologie, Abhandlungen, v. 182, p. 303-354.
44. Jaffey, A.H., Flynn, K.F., Glendenin, L.E., Bentley, W.C., and Essling, A.M., 1971, Precision measurement of half-lives and specific activities of 235U and 238U: Physical Review, v. C4, p. 1889-1906.
45. Jeppsson, L., 1997a, A new latest Telychian, Sheinwoodian and early Homerian (Early Silurian) standard conodont zonation: Transactions of the Royal Society of Edinburgh- Earth Sciences, v. 88, p. 91-114, doi:10.1017/S0263593300006854.
46. Jeppsson, L., 1997b, The anatomy of the mid-Early Silurian Ireviken event and a scenario for P-S events, in Brett, C.E., and Baird, G.C., eds., Paleontological Events: Stratigraphic, Ecological, and Evolutionary Implications: New York, Columbia University Press, p. 451-492.
47. Jeppsson, L., 1998, Silurian oceanic events: Summary of general characteristics, in Landing, E., and Johnson, M.E., eds., Silurian Cycles: Linkages of Dynamic Stratigraphy with Atmospheric, Oceanic and Tectonic Changes: New York State Museum Bulletin, v. 491, p. 239-257.
48. Jeppsson, L., and Calner, M., 2003, The Silurian Mulde event and a scenario for secundo-secundo events: Transactions of the Royal Society of Edinburgh, v. 93, p. 135-154.
49. Jeppsson, L., Aldridge, R.J., and Dorning, K.J., 1995, Wenlock (Silurian) oceanic episodes and events: Journal of the Geological Society of London, v. 152, p. 487-498, doi:10.1144/gsjgs.152.3.0487.
50. Jeppsson, L., Eriksson, M.E., and Calner, M., 2006, A latest Llandovery to latest Ludlow high-resolution biostratigraphy based on the Silurian of Gotland- A summary: GFF, v. 128, p. 109-114, doi:10.1080/11035890601282109.
51. Kaljo, D., Boucot, A.J., Corfield, R.M., Koren', T.N., Križ, J., Le Hérrisé, A., Männik, P., Märs, T., Nestor, V., Shaver, R.H., Siveter, D.J., and Viira, V., 1996, Silurian bio-events, in Walliser, O.H., ed., Global Events and Events Stratigraphy in the Phanerozoic: Berlin, Springer-Verlag, p. 173-224.
52. Kaljo, D., Grytsenko, V., Martma, T., and Mõtus, M.-A., 2007, Three global carbon isotope shifts in the Silurian of Podolia (Ukraine): Stratigraphical implications: Estonian Journal of Earth Sciences, v. 56, p. 205-220, doi:10.3176/earth.2007.02.
53. Kauffman, E.G., 1995, Global change leading to biodiversity crisis in a greenhouse world: The Cenomanian-Turonian (Cretaceous) mass extinction, in Effects of Past Global Change on Life: Washington, D.C., National Academy Press, p. 47-72.
54. Kauffman, E.G., and Harries, P.J., 1996, The importance of crisis progenitors in recovery from mass extinctions, in Hart, M.B., ed., Biotic Recovery from Mass Extinction Events: Geological Society of London Special Publication 102, p. 15-39.
55. Kauffman, E.G., Elder, W.P., and Sageman, B.B., 1991, Highresolution correlation: A new tool in chronostratigraphy, in Einsele, G., Ricken, W., and Seilacher, A., eds., Cycles and Events in Stratigraphy: Berlin, Springer-Verlag, p. 795-819.
56. Kiipli, T., Radzevičius, S., Kallaste, T., Motuza, T., Jeppsson, L., and Wickström, L.M., 2008a, Wenlock bentonites in Lithuania and correlation with bentonites from sections in Estonia, Sweden and Norway: GFF, v. 130, p. 203-210.
57. Kiipli, T., Jeppsson, L., Kallaste, T., and Söderlund, U., 2008b, Correlation of Silurian bentonites from Gotland and the eastern Baltic using sanidine phenocryst composition, and biostratigraphical consequences: Journal of the Geological Society of London, v. 165, p. 211- 220, doi:10.1144/0016-76492006-095.
58. Kiipli, T., Kallaste, T., Nestor, V., and Loydell, D.K., 2010, Integrated Telychian (Silurian) K-bentonite chemostratigraphy and biostratigraphy in Estonia and Latvia: Lethaia, v. 43, p. 32-44, doi:10.1111/j.1502-3931.2009.00162.x.
59. 13C chemostratigraphy, and recognition of the Silurian/Devonian boundary in the Cherry Valley, New York, region of the Appalachian Basin, in Over, D.J., ed., Conodont Studies Commemorating the 150th Anniversary of the First Conodont Paper (Pander, 1856) and the 40th Anniversary of the Pander Society: Palaeontographica Americana, v. 62, p. 57-73 (Allen Press, Lawrence, Kansas, USA).
60. Koren', T.N., 1991, The C. lundgreni extinction event in Central Asia and its bearing on graptolite biochronology within the Homerian: Proceedings of Estonian Academy of Science: Geology, v. 40, p. 74-78.
61. Koren', T.N., and Urbanek, A., 1994, Adaptive radiation of monograptids after the late Wenlock crisis: Acta Palaeontologica Polonica, v. 39, p. 137-167.
62. Kunk, M.J., Sutter, J., Obradovich, J.D., and Lamphere, M.A., 1985, Age of biostratigraphic horizons within the Ordovician and Silurian Systems, in Snelling, N.J., ed., The Chronology of the Geological Record: British Geological Survey Memoir 10, p. 89-92.
63. Laufeld, S., 1974, Reference localities for palaeontology and geology in the Silurian of Gotland: Sveriges Geologiska Undersökning, C 705, p. 1-172.
64. Lawson, J.D., and White, D.E., 1989, The Ludlow Series in the Ludlow area, in Holland, C.H., and Bassett, M.G., eds., A Global Standard for the Silurian System: National Museum of Wales, Geological Series 9, p. 73-90.
65. Lees, D.C., Fortey, R.A., and Cocks, L.R.M., 2002, Quantifying paleogeography using biogeography: A test case for the Ordovician and Silurian of Avalonia based on brachiopods and trilobites: Paleobiology, v. 28, p. 343-363, doi:10.1666/0094-8373(2002)028<0343: QPUBAT>2.0.CO;2.
66. Lenz, A.C., 1993, Late Wenlock-Ludlow (Silurian) extinction, evolution, and biostratigraphy: Perspectives from Arctic Canada: Canadian Journal of Earth Sciences, v. 30, p. 491-498, doi:10.1139/e93-038.
67. Lenz, A.C., 1994, Extinction and opportunistic evolution among late Wenlock graptolites: Lethaia, v. 27, p. 111- 117, doi:10.1111/j.1502-3931.1994.tb01564.x.
68. Lenz, A.C., and Kozłowska-Dawidziuk, A., 2001, Upper Wenlock (Silurian) graptolites from Arctic Canada: Pre-extinction, lundgreni biozone fauna: Palaeontographica Canadiana, v. 20, p. 1-61.
69. Lenz, A.C., and Kozłowska-Dawidziuk, A., 2002, Late Wenlock and early Ludlow graptolite extinction, evolution and diversification: A reassessment: Special Papers in Palaeontology, v. 67, p. 171-183.
70. Lenz, A.C., Noble, P.J., Masiak, M., Poulson, S.R., and Kozłowska, A., 2006, The lundgreni extinction event: Integration of paleontological and geochemical data from Arctic Canada: GFF, v. 128, p. 153-158, doi: 10.1080/11035890601282153.
71. Loydell, D.K., 1998, Early Silurian sea-level changes: Geological Magazine, v. 135, p. 447-471, doi:10.1017/S0016756898008917.
72. Loydell, D.K., 2008, The base of the Wenlock Series: Silurian Times, v. 15, p. 10-12.
73. Loydell, D.K., and Cave, R., 1996, The Llandovery-Wenlock boundary and related stratigraphy in eastern mid-Wales with special reference to the Banwy River section: Newsletters on Stratigraphy, v. 34, p. 39-64.
74. Ludwig, K.R., 2003, User's Manual for Isoplot 3.00: Berkeley, California, Berkeley Geochronology Center, 70 p.
75. Mabillard, J.E., and Aldridge, R.J., 1985, Microfossil distribution across the base of the Wenlock Series in the type area: Palaeontology, v. 28, p. 89-100.
76. Männik, P., Barrick, J.E., and Jeppsson, L., 2002, Walliserodus Serpagli 1967 in the Silurian-Apparatus, taxonomy, and distribution: Strata, v. 12, p. 42.
77. 13C stratigraphy of the Homerian (Wenlock) of the English Midlands, in Palaeontological Association 2009 Annual Meeting Abstracts: Birmingham, UK, University of Birmingham, p. 55-56.
78. Masiak, M., 1999, Zapis zdarzenia Cyrtograptus lundgreni w górnowenlockim zespole akritarchowym Gór Świe{ogonek}tokrzyskich: Przegl Geologiczny, v. 47, p. 359-360.
79. Matteson, D.K., and Ebert, J.R., 2011, Where does the Devo nian begin in the Appalachian standard succession? Recognition of the Silurian-Devonian boundary event in the Helderberg Group of New York State: Geological Society of America Abstracts with Programs, v. 43, no. 1, p. 97.
80. Mattinson, J.M., 2005, Zircon U-Pb chemical abrasion (CATIMS) method: Combined annealing and multi-step dissolution for improved precision and accuracy of zircon ages: Chemical Geology, v. 220, p. 47-66, doi: 10.1016/j.chemgeo.2005.03.011.
81. 238U by multi-step CA-TIMS measurements of closed-system natural zircon samples: Chemical Geology, v. 275, p. 186-198, doi:10.1016/j.chemgeo.2010.05.007.
82. Melchin, M.J., Cooper, R.A., and Sadler, P.M., 2004, The Silurian Period, in Gradstein, F.M., Ogg, J.G., and Smith, A.G., eds., A Geologic Time Scale 2004: Cambridge, UK, Cambridge University Press, p. 188-201.
83. Melchin, M.J., Cooper, R.A., Sadler, P.M., and Cramer, B.D., 2012, The Silurian Period, in Gradstein, F.M., Ogg, J.G., Ogg, G., and Schmitz, M. eds., The Geologic Time Scale 2012: Elsevier, p. 539-572, doi:10.1016/B978-0-444-59425-9.00021-4 (in press).
84. Meyers, S.R., and Sageman, B.B., 2007, Quantification of deep-time orbital forcing by average spectral misfit: American Journal of Science, v. 307, p. 773-792, doi: 10-2475/05.2001.01.
85. Mullins, G.L., and Aldridge, R.J., 2004, Chitinozoan biostratigraphy of the basal Wenlock Series (Silurian) global stratotype section and point: Palaeontology, v. 47, p. 745-773, doi:10.1111/j.0031-0239.2004.00387.x.
86. Munnecke, A., Samtleben, C., and Bickert, T., 2003, The Ireviken event in the Lower Silurian of Gotland, Sweden-Relation to similar Palaeozoic and Proterozoic events: Palaeogeography, Palaeoclimatology, Palaeo ecology, v. 195, p. 99-124, doi:10.1016/S0031 -0182(03)00304-3.
87. Munnecke, A., Calner, M., Harper, D.A.T., and Servais, T., 2010, Ordovician and Silurian sea-water chemistry, sea level, and climate: A synopsis: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 296, p. 389-413, doi:10.1016/j.palaeo.2010.08.001.
88. 13C profiles from the Cape Phillips Formation, Arctic Canada, and their relation to biotic events: Canadian Journal of Earth Sciences, v. 42, p. 1419-1430, doi:10.1139/e05-055.
89. Odin, G.S., Hunziker, J.C., Jeppsson, L., and Spjeldnaes, N., 1986, Ages radiometriques K-Ar de biotites pryoclastiques sedimentées dans le Wenlock de Gotland (Suède), in Odin, G.S., ed., Calibration of the Phanerozoic Time Scale: Chemical Geology, Isotope Geoscience Section, v. 59, p. 117-125.
90. Ogg, J.G., Ogg, G., and Gradstein, F.M., eds., 2008, The Concise Geologic Time Scale: Cambridge, UK, Cambridge University Press, 177 p.
91. Pharaoh, T.C., England, R.W., Verniers, J., and Zelazniewicz, A., 1997, Introduction: Geological and geophysical studies in the Trans-European suture zone: Geological Magazine, v. 134, p. 585-590, doi:10.1017/S0016756897007619.
92. Pore{ogonek}bska, E., Kozłowska-Dawidziuk, A., and Masiak, M., 2004, The lundgreni event in the Silurian of the East European platform, Poland: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 213, p. 271-294.
93. Radzevičius, S., Paškevičius, J., and Meidla, T., 2008, Evolution and phylogenesis of some Silurian graptolites: Geologijos Akiračiai (Journal of the Geological Society of Lithuania), v. 2, p. 35-42.
94. Ray, D.C., 2007, The correlation of Lower Wenlock Series (Silurian) bentonites from the Lower Hill Farm and Eastnor Park boreholes, Midland Platform, England: Proceedings of the Geologists' Association, v. 118, p. 175-185.
95. Ray, D.C., ed., 2011, Siluria Revisited: A Field Guide: International Subcommission on Silurian Stratigraphy, Field Meeting, 2011, Ludlow, England: International Subcommission on Silurian Stratigraphy, 166 p., available online http://www.igcp591.org.
96. Ray, D.C., and Thomas, A.T., 2007, Carbonate depositional environments, sequence stratigraphy and exceptional skeletal preservation in the Much Wenlock Limestone Formation (Silurian) of Dudley, England: Palaeontology, v. 50, p. 197-222, doi:10.1111/j.1475-4983.2006.00607.x.
97. Ray, D.C., Brett, C.E., Thomas, A.T., and Collings, A.V.J., 2010, Late Wenlock sequence stratigraphy in central England: Geological Magazine, v. 147, p. 123-144, doi:10.1017/S0016756809990197.
98. Ray, D.C., Thomas, A.T., and Marshall, C., 2011a, The Much Wenlock Limestone Formation: The Nature Conservancy Council Cutting, Wren's Nest Hill, Dudley, in Ray, D.C., ed., Siluria Revisited: A Field Guide: International Subcommission on Silurian Stratigraphy, Field Meeting, 2011, Ludlow, England: International Subcommission on Silurian Stratigraphy, p. 122-130, available online at http://www.igcp591.org.
99. Ray, D.C., Thomas, A.T., and Marshall, C., 2011b, Latest Homerian obrution deposits: Upper Quarried Limestone Member, Quarry Trench, Mons Hill, Dudley, in Ray, D.C., ed., Siluria Revisited: A Field Guide: International Subcommission on Silurian Stratigraphy, Field Meeting, 2011, Ludlow, England: International Subcommission on Silurian Stratigraphy, p. 131-136, available online at http://www.igcp591.org.
100. Ray, D.C., Collings, A.V.J., Worton, G.J., and Jones, G., 2011c, Upper Wenlock bentonites from Wren's Nest Hill, Dudley; comparisons with prominent bentonites along Wenlock Edge, Shropshire, England: Geological Magazine, v. 148, p. 670-681, doi:10.1017/S0016756811000288.
101. Renne, P.R., Karner, D.B., and Ludwig, K.R., 1998, Radioisotope dating-Absolute ages aren't exactly: Science, v. 282, no. 5395, p. 1840-1841, doi:10.1126/science .282.5395.1840.
102. Ross, R.J., Naeser, C.W., Izett, G.A., Obradovich, J.D., Bassett, M.G., Hughes, C.P., Cocks, L.R.M., Dean, W.T., Ingham, J.K., Rickards, R.B., Sheldon, P.R., Toghill, P., Whittington, H.B., and Zalasiewicz, J., 1982, Fissiontrack dating of British Ordovician and Silurian stratotypes: Geological Magazine, v. 119, p. 135-153, doi: 10.1017/S0016756800025838.
103. Sadler, P.M., 2004, Quantitative biostratigraphy: Achieving finer resolution in global correlation: Annual Review of Earth and Planetary Sciences, v. 32, p. 187-213, doi:10.1146/annurev.earth.32.101802.120428.
104. Sadler, P.M., and Cooper, R.A., 2011, Graptoloid evolutionary rates: Sharp contrast between Ordovician and Silurian, in Gutíerrez-Marco, J.C., Rábano, I., and García-Bellido, D., eds., Ordovician of the World (from the 11th International Symposium on the Ordovician System): Publicaciones del Instituto Geológico y Minero de España, Serie Cuadernos del Museo Geominero 14, p. 499-504.
105. Sadler, P.M., Cooper, R.A., and Melchin, M., 2009, Highresolution, early Paleozoic (Ordovician-Silurian) time scales: Geological Society of America Bulletin, v. 121, p. 887-906, doi:10.1130/B26357.1.
106. Sageman, B.B., Meyers, S.R., and Arthur, M.A., 2006, Orbital time scale and a new C-isotope record for Cenomanian-Turonian boundary stratotype: Geology, v. 34, p. 125-128, doi:10.1130/G22074.1.
107. Saltzman, M.R., 2005, Phosphorus, nitrogen, and the redox evolution of the Paleozoic oceans: Geology, v. 33, p. 573-576, doi:10.1130/G21535.1.
108. Samson, S.D., Kyle, P.R., and Alexander, E.C., Jr., 1988, Correlation of North American Ordovician bentonites using apatite chemistry: Geology, v. 16, p. 444-447, doi:10.1130/0091-7613(1988)016<0444:CONAOB >2.3.CO;2.
109. Samson, S.D., Patchett, P.J., Roddick, J.C., and Parrish, R.R., 1989, Origin and tectonic setting of Ordovician bentonites in North America: Isotopic and age constraints: Geological Society of America Bulletin, v. 101, p. 1175-1181, doi:10.1130/0016-7606(1989)101<1175: OATSOO>2.3.CO;2.
110. Samson, S.D., Matthews, S.V.L., Mitchell, C.E., and Goldman, D., 1995, Tephrochronology of highly altered ash beds: The use of trace element and strontium isotope geochemistry of apatite phenocrysts to correlate K-bentonites: Geochimica et Cosmochimica Acta, v. 59, p. 2527-2536, doi:10.1016/0016-7037 (95)00147-6.
111. Samtleben, C., Munnecke, A., Bickert, T., and Pätzold, J., 1996, The Silurian of Gotland (Sweden): Facies interpretation based on stable isotopes in brachiopod shells: Geologische Rundschau, v. 85, p. 278-292, doi:10.1007/BF02422234.
112. Schärer, U., 1984, The effect of initial 230Th disequilibrium on young U-Pb ages: The Makalu case, Himalaya: Earth and Planetary Science Letters, v. 67, no. 2, p. 191-204, doi:10.1016/0012-821X(84)90114-6.
113. Schmitz, M.D., and Schoene, B., 2007, Derivation of isotope ratios, errors, and error correlations for U-Pb geo chronol ogy using Pb-205-U-235-(U-233)-spiked isotope dilution thermal ionization mass spectrometric data: Geochemistry, Geophysics, Geosystems, v. 8, Q08006, doi:10.1029/2006GC001492.
114. Schoene, B., Crowley, J.L., Condon, D.J., Schmitz, M.D., and Bowring, S.A., 2006, Reassessing the uranium decay constants for geochronology using ID-TIMS U-Pb data: Geochimica et Cosmochimica Acta, v. 70, no. 2, p. 426-445, doi:10.1016/j.gca.2005.09.007.
115. Shaw, G.H., 2003, Trace element chemistry of individual apatite phenocrysts as a tool for fingerprinting altered volcanic ash beds: Assessing interbed and intrabed variation at local and regional scales: Geological Society of America Bulletin, v. 115, p. 933-942, doi:10.1130/0016-7606(2003)115<933:TECOIA>2.0.CO;2.
116. Siveter, D.J., 2009, Silurian, in Whittaker, J.E., and Hart, M.B., eds., Ostracods in British Stratigraphy: The Micro palaeontological Society Special Publication v. 3, no. TMS003, p. 45-90.
117. Smethurst, M.A., and McEnroe, S.A., 2003, The palaeolatitude controversy in the Silurian of Newfoundland resolved: New palaeomagnetic results from the Central Mobile belt: Tectonophysics, v. 362, p. 83-104, doi:10.1016/S0040-1951(02)00632-7.
118. Snäll, S., 1977, Silurian and Ordovician bentonites of Gotland (Sweden): Stockholm Contributions in Geology, v. 31, p. 1-80.
119. Štorch, P., 1995, Biotic crises and post-crisis recoveries recorded by Silurian planktonic graptolite faunas of the Barrandian area (Czech Republic): Geolines (Prague), v. 3, p. 59-70.
120. 18O) on Gotland, Sweden: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 230, p. 1-31, doi:10.1016/j.palaeo.2005.07.003.
121. Suttner, T.J., 2009, Lower Devonian conodont from the 'Baron von Kottwitz' quarry (southern Bergenland, Austria), in Over, D.J., ed., Conodont Studies Commemorating the 150th Anniversary of the First Conodont Paper (Pander, 1856) and the 40th Anniversary of the Pander Society: Palaeontographica Americana, v. 62, p. 75-87.
122. Thomas, A.T., and Ray, D.C., 2011, Pitch Coppice: GSSP for the base of the Ludlow Series and Gorstian Stage, in Ray, D.C., ed., Siluria Revisited: A Field Guide: Inter national Subcommission on Silurian Stratigraphy, Field Meeting, 2011, Ludlow, England: International Subcommission on Silurian Stratigraphy, p. 81-85, available online at http://www.igcp591.org.
123. Tucker, R.D., and McKerrow, W.S., 1995, Early Paleozoic chronology: A review in light of new U-Pb zircon ages from Newfoundland and Britain: Canadian Journal of Earth Sciences, v. 32, p. 368-379, doi:10.1139/e95-032.
124. Tucker, R.D., Krogh, T.E., Ross, R.J., Jr., and Williams, S.H., 1990, Time-scale calibration by high-resolution U-Pb zircon dating of interstratified volcanic ashes in the Ordovician and Lower Silurian stratotypes of Britain: Earth and Planetary Science Letters, v. 100, p. 51-58, doi:10.1016/0012-821X(90)90175-W.
125. Tucker, R.D., Bradley, D.C., Ver Straeten, C.A., Harris, A.G., Ebert, J.R., and McCutcheon, S.R., 1998, New U-Pb zircon ages and the duration and division of Devonian time: Earth and Planetary Science Letters, v. 158, p. 175-186, doi:10.1016/S0012-821X(98)00050-8.
126. van Staal, C.R., Whalen, J.B., Valverde-Vaquero, P., Zagorevski, A., and Rogers, N., 2009, Pre-Carboniferous, episodic accretion-related, orogenesis along the Laurentian margin of the Northern Appalachians, in Murphy, J.B., Keppie, J.B., and Hynes, A.J., eds., Ancient Orogens and Modern Analogues: Geological Society of London Special Publications 327, p. 271-316.
127. Vecoli, M., and Samuelsson, J., 2001, Quantitative evaluation of microplankton palaeobiogeography in the Ordovician-Early Silurian of the northern Trans-European suture zone: Implications for the timing of the Avalonia-Baltica collision: Review of Palaeobotany and Palynology, v. 115, p. 43-68, doi:10.1016/S0034 -6667(01)00047-1.
128. Watson, E.B., and Green, T.H., 1981, Apatite/liquid partition coefficient for the rare earth elements and strontium: Earth and Planetary Science Letters, v. 56, p. 405-421, doi:10.1016/0012-821X(81)90144-8.
129. Wendt, I., and Carl, C., 1991, The statistical distribution of the mean squared weighted deviation: Chemical Geology, Isotope Geoscience Section, v. 86, no. 4, p. 275- 285, doi:10.1016/0168-9622(91)90010-T.
130. Woodcock, N.H., 2000, Introduction to the Silurian: Geological Conservation Review Series, v. 19, p. 3-22.
131. Wyborn, D., Owen, N., Compston, W., and McDougall, I., 1982, The Laidlaw Volcanics: A Late Silurian point on the geological time scale: Earth and Planetary Science Letters, v. 59, p. 90-100, doi:10.1016/0012-821X (82)90119-4.
132. Zalasiewicz, J.A., Taylor, L., Rushton, A.W.A., Loydell, D.K., Rickards, R.B., and Williams, M., 2009, Graptolites in British stratigraphy: Geological Magazine, v. 146, p. 785-850, doi:10.1017/S0016756809990434.