<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head> <title>UTas ePrints - Early Mesoproterozoic intrusive breccias in Yukon, Canada: the role of hydrothermal systems in reconstructions of North America and Australia</title> <script type="text/javascript" src="http://eprints.utas.edu.au/javascript/auto.js"><!-- padder --></script> <style type="text/css" media="screen">@import url(http://eprints.utas.edu.au/style/auto.css);</style> <style type="text/css" media="print">@import url(http://eprints.utas.edu.au/style/print.css);</style> <link rel="icon" href="/images/eprints/favicon.ico" type="image/x-icon" /> <link rel="shortcut icon" href="/images/eprints/favicon.ico" type="image/x-icon" /> <link rel="Top" href="http://eprints.utas.edu.au/" /> <link rel="Search" href="http://eprints.utas.edu.au/cgi/search" /> <meta content="Thorkelson, D.J." name="eprints.creators_name" /> <meta content="Mortensen, J.K." name="eprints.creators_name" /> <meta content="Davidson, G.J." name="eprints.creators_name" /> <meta content="Creaser, R.A." name="eprints.creators_name" /> <meta content="Perez, W.A." name="eprints.creators_name" /> <meta content="Abbott, J.G." name="eprints.creators_name" /> <meta content="dthorkel@sfu.ca" name="eprints.creators_id" /> <meta name="eprints.creators_id" /> <meta content="Garry.Davidson@utas.edu.au" name="eprints.creators_id" /> <meta name="eprints.creators_id" /> <meta name="eprints.creators_id" /> <meta name="eprints.creators_id" /> <meta content="article" name="eprints.type" /> <meta content="2007-09-04" name="eprints.datestamp" /> <meta content="2008-01-23T04:49:14Z" name="eprints.lastmod" /> <meta content="show" name="eprints.metadata_visibility" /> <meta content="Early Mesoproterozoic intrusive breccias in Yukon, Canada: the role of hydrothermal systems in reconstructions of North America and Australia" name="eprints.title" /> <meta content="pub" name="eprints.ispublished" /> <meta content="260100" name="eprints.subjects" /> <meta content="restricted" name="eprints.full_text_status" /> <meta content="Proterozoic; Yukon; Rodinia; Breccia; Geochronology; Continental reconstructions" name="eprints.keywords" /> <meta content="The definitive version is available online at http://www.sciencedirect.com/" name="eprints.note" /> <meta content="In northern Yukon, Canada, numerous breccia zones of early Mesoproterozoic age (ca. 1.6 Ga) are targets for mineral exploration. Collectively termed Wernecke Breccia, they are characterized by disseminated specular hematite and local enrichment of Cu, Co, U and Au. The breccias are hosted mainly by the Paleoproterozoic Wernecke Supergroup, a 13-km thick basinal to platformal succession of carbonate and fine-grained clastic rocks. Brecciation occurred after the Wernecke Supergroup was fully lithified, deformed, and locally metamorphosed. The breccia zones were generated by forceful explosions of volatile-rich fluids within the crust. The source of the fluids is uncertain, but may be related to igneous intrusions at depth. Rapid expansion of the fluids shattered large volumes of country rock, mainly sedimentary rocks of the Wernecke Supergroup, and dioritic to syenitic rocks of the Bonnet Plume River intrusions. In the central parts of the breccia zones, fragments underwent considerable motion, and in some cases became rounded from abrasion. Venting of brecciated rock and fluid is considered likely, but surface deposits are nowhere preserved. At one locality, large blocks of country rock foundered into open space near the top of a breccia zone, forming a fallback megabreccia. Faulting may have been active concurrently with brecciation. Breccia fragments are cemented together by hematite, quartz, carbonate, chlorite, feldspar, mica, and other minerals. In most cases, clasts and wallrocks were hydrothermally altered, leading to metasomatic growth of secondary minerals including flecks of hematite or rhombs of dolomite. Widely disseminated earthy hematite and local potassic alteration in the breccia clasts resulted in color changes from original drab hues of gray and brown to striking pink and red. Clasts with embayments rimmed with secondary minerals such as specular hematite are evidence for the dissolution of clasts or their diagenetic cements by hydrothermal fluids. The main phase of brecciation and metasomatism occurred at ca. 1.6 Ga, as indicated by a 15955 Ma U-Pb date on titanite. Subsequent minor hydrothermal events related to emplacement of the Hart River intrusions and Bear River dykes occurred at 1382.87.4 Ma (U-Pb rutile) and ca. 1270 Ma (U-Pb baddeleyite), respectively. Mineralized breccias at and near the Olympic Dam deposit in South Australia mineralogically and texturally resemble, and have nearly the same age as, the Wernecke Breccias. These similarities suggest that both breccia provinces developed from related systems of hydrothermal activity, and provide additional evidence for models linking the cratons of North America and Australia in Proterozoic time." name="eprints.abstract" /> <meta content="2001-10-01" name="eprints.date" /> <meta content="published" name="eprints.date_type" /> <meta content="Precambrian Research" name="eprints.publication" /> <meta content="111" name="eprints.volume" /> <meta content="1-4" name="eprints.number" /> <meta content="31-55" name="eprints.pagerange" /> <meta content="10.1016/S0301-9268(01)00155-3" name="eprints.id_number" /> <meta content="UNSPECIFIED" name="eprints.thesis_type" /> <meta content="TRUE" name="eprints.refereed" /> <meta content="0301-9268" name="eprints.issn" /> <meta content="http://dx.doi.org/10.1016/S0301-9268(01)00155-3" name="eprints.official_url" /> <meta content="Abbott, J.G., 1997. Geology of the upper Hart River Area, Eastern Ogilvie Mountains, Yukon Territory (116A/10. 116A/11). Exploration and Geological Services Division, Yukon, Indian and Northern Affairs Canada Bull. 9, p. 76. Abbott, G., Thorkelson, D., Creaser, R. Bevier, M.L., Mortensen, J., 1997. New correlations among Proterozoic successions and intrusive breccias in the Ogilvie and Wernecke Mountains, Yukon. In: Cook, F., Erdmer, P. (Compilers), Slave-Northern Cordillera Lithospheric Evolution (SNORCLE) Transect and Cordilleran Tectonics Workshop Meeting (March 7-9), University of Calgary, Lithoprobe Rept., 56: 188-197. Aitken, J.D., McMechan, M.E., 1992. Middle Proterozoic assemblages, Chapter 5. In: Gabrielse, H., Yorath, C.J. (Eds.), Geology of the Cordilleran Orogen in Canada. Geol. Surv. Can, pp. 97-124. Archer, A., Bell, R.T., Thorpe, R.I., 1986. Age relationships from U-Th-Pb isotope studies of uranium mineralization in Wernecke breccias, Yukon Territory. Current Research, Part A, Geol. Surv. Can. Pap. 86 (1A), 385-391. Archer, A., Schmidt, U., 1978. Mineralized breccias of early Proterozoic age, Bonnet Plume River district, Yukon Territory. Can. Min. Met. Bull. 71, 53-58. Bell, R.T., 1968. Proterozoic stratigraphy of northeastern British Columbia. Geol. Surv. Can. Pap. 67-68, 75. Bell, R.T., 1982. Comments on the geology and uraniferous mineral occurrences of the Wernecke Mountains, Yukon and District of Mackenzie. Current Research, Part B, Geol. Surv. Can. Pap. 82 (1B), 279-284. Bell, R.T., 1986a. Geological map of northeastern Wernecke Mountains, Yukon Territory. Geol. Surv. Can. Open File 1207. Bell, R.T., 1986b. Megabreccias in northeastern Wernecke Mountains, Yukon Territory. Current Research, Part A, Geol. Surv. Can. Pap. 1986-1A, 375-384. Bell, R.T., 1989. A conceptual model for development of megabreccias and associated mineral deposits in Wernecke Mountains, Canada, Copperbelt, Zaire, and Flinders Range, Australia. In: Uranium resources and geology of North America, Proc. technical committee meeting organized by the International Atomic Energy Agency and held in Saskatoon, Canada, Sept. 1-3, 1987. International Atomic Energy Agency, Vienna, pp. 149-169. Bell, R.T., Delaney, G.D., 1977. Geology of some uranium occurrences in Yukon Territory. Current Research, Part A, Geol. Surv. Can. Pap. 77-1A, 33-37. Bell, R.T., Jefferson, C.W., 1987. A hypothesis for an Australian-Canadian connection in the late Proterozoic and the birth of the Pacific Ocean. In: Proc. Pacific Rim Congr. 87, Parkville, Victoria, Australia. Australasian Institute of Mining and Metallurgy, pp. 39-50. Blake, D.H., 1987. Geology of the Mount Isa Inlier and environs, Queensland and Northern Territory. Bureau of Mineral Resources Bull. 225, 83. Burrett, C., Berry, R., 2000. Proterozoic Australia-Western United States (AUSWUS) fit between Laurentia and Australia. Geology 28, 103-106. Conly, A.G., 1993. Mineralogy and mineral chemistry of hydrothermal alteration of Wernecke Breccia from the Slats Creek (NTS 106D/16) map area, Wernecke Mountains, Yukon. Unpublished Report, Carleton University, Ottawa, p. 60. Conly, A.G., Taylor, R.P., Thorkelson, D.J., Fallick, A.E., 1995. Petrography, mineralogy, and stable isotope geochemistry of hydrothermal alteration of Wernecke Breccia, Slats Creek area, Yukon Territory. Geol. Assoc. Can. Prog. Abstr. 20, A-116. Cook, F.A., 1992. Racklan Orogen. Can. J. Earth Sci. 29, 2490-2496. Cook, F.A., van der Velden, A.J., Hall, K.W., Roberts, B.J., 1998. Tectonic Delamination of the Precambrian Lithosphere in Northwestern Canada Mapped by LITHOPROBE. LITHOPROBE Rept. 64, 58-69. Creaser, R.A., 1995. Neodymium isotopic constraints for the origin of Mesoproterozoic felsic magmatism, Gawler Craton, South Australia. Can. J. Earth Sci. 32, 460-471. Cross, K.C., 1993. Mineralisation associated with the Gawler Range Volcanics and Hiltaba Suite granitoids: Acropolis and Wirrda Well deposits. In: Drexel, J.F., Preiss, W.V., Parker, A.J. (Eds.), The Geology of South Australia. South Australian Geological Survey, Bull. 54: 138 Cross, K.C., Daly, S.J., Flint, R.B., 1993. Mineralisation associated with the Gawler Range Volcanics and Hiltaba Suite granitoids: Olympic Dam deposit. In: Drexel, J.F., Preiss, W.V., Parker, A.J. (Eds.), The Geology of South Australia. South Australian Geological Survey, Bull. 54: 132-138. Daly, S.J., Fanning, C.M., Fairclough, M.C., 1998. Tectonic evolution and exploration potential of the Gawler Craton, South Australia. AGSO J. Aust. Geol. Geophys. 17, 145-168. Dalziel, I.W.D., 1991. Pacific margins of Laurentia and East Antarctica-Australia as a conjugate rift pair: evidence and implications for an Eocambrian supercontinent. Geology 19, 598-601. Davidson, G.J., Patterson, H.L., 1993. Oak Dam East: a prodigious, uranium-bearing, massive iron-oxide body on the Stuart Shelf. Geological Society of Australia 34, 18-19 Abstr. Delaney, G.D., 1981. The Mid-Proterozoic Wernecke Supergroup, Wernecke Mountains, Yukon Territory. In: Campbell, F.H.A. (Ed.), Proterozoic Basins of Canada, Geol. Surv. Can. Pap. 81-10, p. 23. Doughty, P.T., Price, R.A., Parrish, R.R., 1998. Geology and U-Pb geochronology of Archean basement and Proterozoic cover in the Priest River complex, northwestern United States, and their implications for Cordilleran structure and Precambrian continent reconstructions. Can. J. Earth Sci. 35, 39-54. Dredge Mitchelmore, M., Cook, F.A., 1994. Inversion of the Proterozoic Wernecke basin during tectonic development of the Racklan Orogen, northwest Canada. Can. J. Earth Sci. 31, 447-457. Eisbacher, G.H., 1981. Sedimentary tectonics and glacial record in the Windermere Supergroup, Mackenzie Mountains, northwestern Canada. Geol. Surv. Can. Pap. 80-27. Eisbacher, G.H., 1985. Late Proterozoic rifting, glacial sedimentation, and sedimentary cycles in the light of Windermere deposition, western Canada. Palaeogeograph. Palaeoclimatol. Palaeoecol. 51, 231-254. Francis, D., 1994. Chemical interaction between picritic magmas and upper crust along the margins of the Muskox intrusion, Northwest Territories. Geol. Surv. Can. Pap. 92-12, p. 94. Gabrielse, H., 1967. Tectonic evolution of the northern Canadian Cordillera. Can. J. Earth Sci. 4, 271-298. Gandhi, S.S., Bell, R.T., 1990. Metallogenic concepts to aid exploration for the giant Olympic Dam-type deposits and their possible derivatives. In: Proceedings of the Eighth Quadrennial IAGOD Symposium, Ottawa, Canada, 1990, pp. 787-802. Gow, P.A., Wall, V.J., Valenta, R.K., 1993. The regional geophysical response of the Stuart Shelf, South Australia. Exploration Geophysics 24, 513-520. Gow, P.A., Wall, V.J., Oliver, N.H.S., Valenta, R.K., 1994. Proterozoic iron oxide (Cu-U-Au-REE) deposits: further evidence of hydrothermal origins. Geology 22, 633-636. Green, L.H., 1972. Geology of Nash Creek, Larsen Creek, and Dawson Creek map-areas, Yukon Territory. Geol. Surv. Can. 364, 157 Mem. Hinde, J.S., 1982. A study of the relationships between the mean element abundances of the Stuart Shelf and Olympic Dam basement lithologies, relative to felsic and mafic rocks. Unpublished Western Mining Report, SS1-1, p. 15. Hitzman, M.W., Oreskes, N., Einaudi, M.T., 1992. Geological characteristics and tectonic setting of Proterozoic iron oxide (Cu-U-Au-REE) deposits. In: Gall, G., Schulz, K. (Eds.), Precambrian Metallogeny Related to Plate Tectonics. Precambrian Res. 58: 241-287. Hoffman, P.F., 1989. Precambrian geology and tectonic history of North America. In: Bally, A.W., Palmer, A.R. (Eds.), The Geology of North America -an overview, Geology of North America, A. Geol. Soc. Am. Boulder, pp. 447-512. Idnurm, M., Giddings, J.W., 1995. Paleoproterozoic- Neoproterozoic North America-Australia link: new evidence from paleomagnetism. Geology 23, 149-152. INAC, 1998. Yukon Minfile. Exploration and Geological Services Division, Yukon, Indian and Northern Affairs, Canada, map areas 106C, 106D. Jefferson, C.W., Parrish, R.R., 1989. Late Proterozoic stratigraphy, U-Pb zircon ages, and rift tectonics, Mackenzie Mountains, northwestern Canada. Can. J. Earth Sci. 26, 1784-1801. Johnson, J.P., Cross, K.C., 1991. Geochronological and Sm- Nd isotopic constraints on the genesis of the Olympic Dam Cu-U-Au-Ag deposit, South Australia. In: Pagel, M., Leroy, J.L. (Eds.), Source, transport and deposition of metals. Proceedings of the 25 years SGA anniversary meeting. Balkema, Rotterdam, pp. 395-400. Karlstrom, K.E., Harlan, S.S., Williams, M.L., McLelland, J., Geissman, J.W., Ahall, K.-I., 1999. Refining Rodinia: geological evidence for the Australia-Western U.S. connection in the Proterozoic. GSA Today 9 (10), 1-6. Krcmarov, R., 1987. The geology, petrology and geochemistry of the volcanic unit at Olympic Dam, South Australia. Unpublished honours thesis, Univ. of Adelaide. Lane, R.A., 1990. Geologic setting and petrology of the Proterozoic Ogilvie Mountains Breccia of the Coal Creek inlier, southern Ogilvie Mountains, Yukon Territory. MSc thesis, Univ. of British Columbia, Vancouver, Canada, p. 223. Laznicka, P., Edwards, R.J., 1979. Dolores Creek, Yukon-a disseminated copper mineralization in sodic metasomatites. Econ. Geol. 74, 1352-1370. Laznicka, P., Gaboury, D., 1988. Wernecke breccias and Fe, Cu, U mineralization: Quartet Mountain-Igor area (NTS 106E). In: Yukon Geology, v. 2. Exploration and Geological Services Division, Yukon, Indian and Northern Affairs Canada, pp. 42-50. LeCheminant, A.N., Heaman, L.M., 1989. Mackenzie igneous events, Canada: middle Proterozoic hotspot magmatism associated with ocean opening. Earth Planet. Sci. Lett. 96, 38-48. Long, D.G.F., Devaney, J.R., Pratt, B.R., 1999. Tectonostratigraphic framework of the Mesoproterozoic Muskwa assemblage, northern British Columbia. In: Cook, F., Erdmer, P. (Compilers), Slave-Northern Cordilleran Cordilleran Lithospheric Evolution (SNORCLE) Transect and Cordilleran Tectonics Workshop Meeting, University of Calgary, Lithoprobe Rept. 69: 112-119. Ludwig, K.R., 1998. Isoplot/Ex, a geochronological toolkit for Microsoft Excel, version 1.00b: Berkeley Geochronology Center, Special Publication No. 1. Mitchell, R.H., 1991. Kimberlites and lamproites: primary sources of diamond. Geosci. Canada 18, 1-16. Moores, E.M., 1991. Southwest U.S.-East Antarctic (SWEAT) connnection: a hypothesis. Geology 19, 425-428. Mortensen, J.K., Ghosh, D. Ferri, F., 1995. U-Pb age constraints of intrusive rocks associated with Copper-Gold porphyry deposits in the Canadian Cordillera. In: Schroeter, T.G. (Ed.), Porphyry deposits of the northwestern Cordillera of North America. Canadian Institute of Mining and Metallurgy, Spec. Vol., 46: 142-158. Norris, D.K., Dyke, L.D., 1997. Chapter 4: Proterozoic. In: Norris, D.K. (Ed.), The Geology, Mineral and Hydrocarbon Potential of Northern Yukon Territory and Northwestern District of Mackenzie. Geol. Surv. Can. Bull. 422: 65-84. Page, R.W., Sun, S-S., 1998. Aspects of geochronology and crustal evolution in the Eastern Fold Belt, Mt. Isa Inlier. Austr. J. Earth Sci. 45, 343-361. Parrish, R.R., Bell, R.T., 1987. Age of the NOR breccia pipe, Wernecke Supergroup, Yukon Territory. In: Radiogenic Age and Isotopic Studies: Report 1. Geol. Surv. Can. Pap. 87-2: 39-42. Parrish, R., Roddick, J.C., Loveridge, W.D., Sullivan, R.W., 1987. Uranium-lead analytical techniques at the geochronology laboratory, Geological Survey of Canada. In: Radiogenic age and isotopic studies, Report 1. Geol. Surv. Can. Pap. 87-2: 3-7. Paterson, H.L., 1988. Stuart Shelf Joint Venture Oak Dam prospect summary report. Unpublished Western Mining Company report K/3148, p. 14.Paterson, H.L., Dalgarno, C.R., Esdale, D.J., Tonkin, D., 1986. Basement geology of the Stuart Shelf region, South Australia. In: 8th Australian Geological Convention, Adelaide, 1986. Excursion Guide, vol. A1, pp. 7-12. Rainbird, R.H., Jefferson, C.W., Young, G.M., 1996. The early Neoproterozoic sedimentary Succession B of northwestern Laurentia: correlations and paleogeographic significance. Geol. Soc. Am. Bull. 108, 454-470. Reeve, J.S., Cross, K.C., Smith, R.N., Oreskes, N., 1990. Olympic Dam copper-uranium-gold-silver deposit. In: Hughes, F.E., (Ed.), Geology of the mineral deposits of Australia and Papua New Guinea. Australasian Institute of Mining and Metallurgy, Monograph 14: 1009-1035 Roddick, J.C., 1987. Generalized numerical error analysis with application to geochronology and thermodynamics. Geochim. Cosmochim. Acta 51, 2129-2135. Ross, G.M., 1991. Tectonic setting of the Windermere Supergroup revisited. Geology 19, 1125-1128. Ross, G.M., Parrish, R.R., Winston, D., 1992. Provenance and U-Pb geochronology of the Mesoproterozoic Belt Supergroup (northwestern United States): implications for age of deposition and pre-Panthalassa plate reconstructions. Earth Planet. Sci. Lett. 113, 57-76. Solomon, M., Groves, D.I., 1994. The Geology and Origin of Australias Mineral Deposits. Oxford University Press, New York, p. 951. Stacey, J.S., Kramer, J.D., 1975. Approximation of terrestrial lead isotope evolution by a two-stage model. Earth Planet. Sci. Lett. 26, 207-221. Steiger, R.H., Ja¨ger, E., 1977. Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology. Earth Planet. Sci. Lett. 36, 359-362. Sugden, T.J., Cross, K.C.,1991. Significance of overprinting fault systems in the Olympic Dam breccia complex. In: Structural Geology and Exploration. University of Western Australia Geology Department and University Extension Publication 25: 93-98. Tempelman-Kluit, D.J., 1981. NOR, summary of assessment work and description of mineral properties. In: Yukon Geology and Exploration, 1979-1980. Exploration and Geological Services Division, Yukon, Indian and Northern Affairs Canada, pp. 300-301. Thorkelson, D.J., 2000. Geology and mineral occurrences of the Slats Creek, Fairchild Lake and Dolores Creek areas, Wernecke Mountains (106D/16, 106C/13, 106C/14), Yukon Territory. Exploration and Geological Services Division, Yukon, Indian and Northern Affairs Canada Bull. 10: p. 73 Thorkelson, D.J., Wallace, C.A., 1993. Development of Wernecke breccias in Slats Creek (106D/16) map area, Wernecke Mountains, Yukon. In: Yukon Exploration and Geology, 1992. Exploration and Geological Services Division, Yukon, Indian and Northern Affairs Canada, pp. 19-30. Thorkelson, D.J., Wallace, C.A., 1995. Geology and mineral occurrences of the Dolores Creek map area (106C/14), Wernecke Mountains, northeastern Yukon. In: Yukon Exploration and Geology, 1994. Exploration and Geological Services Division, Yukon, Indian and Northern Affairs Canada, pp. 19-30. Thorkelson, D.J., Wallace, C.W., 1998a. Geological map of Slats Creek area, Wernecke Mountains, Yukon (106D/16). Indian and Northern Affairs Canada, Exploration and Geological Services Division, Geoscience Map 1998-9, scale 1:50 000. Thorkelson, D.J., Wallace, C.W., 1998b. Geological map of Fairchild Lake area, Wernecke Mountains, Yukon (106C/ 13). Indian and Northern Affairs Canada, Exploration and Geological Services Division, Geoscience Map 1998-10, scale 1:50 000 Thorkelson, D.J., Wallace, C.W., 1998c. Geological map of Dolores Creek area, Wernecke Mountains, Yukon (106C/14). Indian and Northern Affairs Canada, Exploration and Geological Services Division, Geoscience Map 1998-11, scale 1:50 000 Thorkelson, D.J., Abbott, J.G., Mortensen, J.K., Creaser, R.A., Villeneuve, M.E., 1998. Proterozoic sedimentation, magmatism, metasomatism and deformation in the Wernecke and Ogilvie Mountains, Yukon. In: Cook, F., Erdmer, P. (Compilers), Slave-Northern Cordillera Lithospheric Evolution (SNORCLE) Transect and Cordilleran Tectonics Workshop Meeting (March 6-8), Simon Fraser University, Lithoprobe Report No. 64, pp. 110-119. Villeneuve, M.E., Theriault, R.J., Ross, G.M., 1991. U-Pb ages and Sm-Nd signature of two subsurface granites from the Fort Simpson magnetic high, northwest Canada. Can. J. Earth Sci. 28, 1003-1008. Wheeler, J.O., McFeely, P., 1991. Tectonic assemblage map of the Canadian Cordillera and adjacent parts of the United States of America. Geol. Surv. Can., Map 1712A, scale 1:2 000 000. Yamashita, K., Creaser, R.A., Jensen, J.E., Heaman, L.M., 2000. Origin and evolution of mid-to late-Archean crust in the Hanikahimajuk Lake area, Slave Province, Canada; Evidence from U-Pb geochronological, geochemical and Nd-Pb isotopic data. Precam. Res. 99, 197-224. Young, G.M., 1992. Late Proterozoic stratigraphy and the Canada-Australian connection. Geology 20, 215-218. Young, G.M., 1995. Are Neoproterozoic glacial deposits preserved on the margins of Laurentia related to the fragmentation of two supercontinents? Geology 23, 153-156." name="eprints.referencetext" /> <meta content="Thorkelson, D.J. and Mortensen, J.K. and Davidson, G.J. and Creaser, R.A. and Perez, W.A. and Abbott, J.G. (2001) Early Mesoproterozoic intrusive breccias in Yukon, Canada: the role of hydrothermal systems in reconstructions of North America and Australia. Precambrian Research, 111 (1-4). pp. 31-55. ISSN 0301-9268" name="eprints.citation" /> <meta content="http://eprints.utas.edu.au/1819/1/Thorkelson%2C_Davidson_et_al_PRE_RES_2001.pdf" name="eprints.document_url" /> <link rel="schema.DC" href="http://purl.org/DC/elements/1.0/" /> <meta content="Early Mesoproterozoic intrusive breccias in Yukon, Canada: the role of hydrothermal systems in reconstructions of North America and Australia" name="DC.title" /> <meta content="Thorkelson, D.J." name="DC.creator" /> <meta content="Mortensen, J.K." name="DC.creator" /> <meta content="Davidson, G.J." name="DC.creator" /> <meta content="Creaser, R.A." name="DC.creator" /> <meta content="Perez, W.A." name="DC.creator" /> <meta content="Abbott, J.G." name="DC.creator" /> <meta content="260100 Geology" name="DC.subject" /> <meta content="In northern Yukon, Canada, numerous breccia zones of early Mesoproterozoic age (ca. 1.6 Ga) are targets for mineral exploration. Collectively termed Wernecke Breccia, they are characterized by disseminated specular hematite and local enrichment of Cu, Co, U and Au. The breccias are hosted mainly by the Paleoproterozoic Wernecke Supergroup, a 13-km thick basinal to platformal succession of carbonate and fine-grained clastic rocks. Brecciation occurred after the Wernecke Supergroup was fully lithified, deformed, and locally metamorphosed. The breccia zones were generated by forceful explosions of volatile-rich fluids within the crust. The source of the fluids is uncertain, but may be related to igneous intrusions at depth. Rapid expansion of the fluids shattered large volumes of country rock, mainly sedimentary rocks of the Wernecke Supergroup, and dioritic to syenitic rocks of the Bonnet Plume River intrusions. In the central parts of the breccia zones, fragments underwent considerable motion, and in some cases became rounded from abrasion. Venting of brecciated rock and fluid is considered likely, but surface deposits are nowhere preserved. At one locality, large blocks of country rock foundered into open space near the top of a breccia zone, forming a fallback megabreccia. Faulting may have been active concurrently with brecciation. Breccia fragments are cemented together by hematite, quartz, carbonate, chlorite, feldspar, mica, and other minerals. In most cases, clasts and wallrocks were hydrothermally altered, leading to metasomatic growth of secondary minerals including flecks of hematite or rhombs of dolomite. Widely disseminated earthy hematite and local potassic alteration in the breccia clasts resulted in color changes from original drab hues of gray and brown to striking pink and red. Clasts with embayments rimmed with secondary minerals such as specular hematite are evidence for the dissolution of clasts or their diagenetic cements by hydrothermal fluids. The main phase of brecciation and metasomatism occurred at ca. 1.6 Ga, as indicated by a 15955 Ma U-Pb date on titanite. Subsequent minor hydrothermal events related to emplacement of the Hart River intrusions and Bear River dykes occurred at 1382.87.4 Ma (U-Pb rutile) and ca. 1270 Ma (U-Pb baddeleyite), respectively. Mineralized breccias at and near the Olympic Dam deposit in South Australia mineralogically and texturally resemble, and have nearly the same age as, the Wernecke Breccias. These similarities suggest that both breccia provinces developed from related systems of hydrothermal activity, and provide additional evidence for models linking the cratons of North America and Australia in Proterozoic time." name="DC.description" /> <meta content="2001-10-01" name="DC.date" /> <meta content="Article" name="DC.type" /> <meta content="PeerReviewed" name="DC.type" /> <meta content="application/pdf" name="DC.format" /> <meta content="http://eprints.utas.edu.au/1819/1/Thorkelson%2C_Davidson_et_al_PRE_RES_2001.pdf" name="DC.identifier" /> <meta content="http://dx.doi.org/10.1016/S0301-9268(01)00155-3" name="DC.relation" /> <meta content="Thorkelson, D.J. and Mortensen, J.K. and Davidson, G.J. and Creaser, R.A. and Perez, W.A. and Abbott, J.G. (2001) Early Mesoproterozoic intrusive breccias in Yukon, Canada: the role of hydrothermal systems in reconstructions of North America and Australia. Precambrian Research, 111 (1-4). pp. 31-55. 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border: solid 1px #ccc; padding: 3px"><tr> <td align="left"><a href="http://eprints.utas.edu.au/cgi/users/home">Login</a> | <a href="http://eprints.utas.edu.au/cgi/register">Create Account</a></td> <td align="right" style="white-space: nowrap"> <form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/search" style="display:inline"> <input class="ep_tm_searchbarbox" size="20" type="text" name="q" /> <input class="ep_tm_searchbarbutton" value="Search" type="submit" name="_action_search" /> <input type="hidden" name="_order" value="bytitle" /> <input type="hidden" name="basic_srchtype" value="ALL" /> <input type="hidden" name="_satisfyall" value="ALL" /> </form> </td> </tr></table></td></tr> <tr> <td class="toplinks"><!-- InstanceBeginEditable name="content" --> <div align="center"> <table width="720" class="ep_tm_main"><tr><td align="left"> <h1 class="ep_tm_pagetitle">Early Mesoproterozoic intrusive breccias in Yukon, Canada: the role of hydrothermal systems in reconstructions of North America and Australia</h1> <p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Thorkelson, D.J.</span> and <span class="person_name">Mortensen, J.K.</span> and <span class="person_name">Davidson, G.J.</span> and <span class="person_name">Creaser, R.A.</span> and <span class="person_name">Perez, W.A.</span> and <span class="person_name">Abbott, J.G.</span> (2001) <xhtml:em>Early Mesoproterozoic intrusive breccias in Yukon, Canada: the role of hydrothermal systems in reconstructions of North America and Australia.</xhtml:em> Precambrian Research, 111 (1-4). pp. 31-55. ISSN 0301-9268</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/1819/1/Thorkelson%2C_Davidson_et_al_PRE_RES_2001.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" border="0" class="ep_doc_icon" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/1819/1/Thorkelson%2C_Davidson_et_al_PRE_RES_2001.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />1352Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input value="2294" name="docid" accept-charset="utf-8" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://dx.doi.org/10.1016/S0301-9268(01)00155-3">http://dx.doi.org/10.1016/S0301-9268(01)00155-3</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">In northern Yukon, Canada, numerous breccia zones of early Mesoproterozoic age (ca. 1.6 Ga) are targets for mineral exploration. Collectively termed Wernecke Breccia, they are characterized by disseminated specular hematite and local enrichment of Cu, Co, U and Au. The breccias are hosted mainly by the Paleoproterozoic Wernecke Supergroup, a 13-km thick basinal to platformal succession of carbonate and fine-grained clastic rocks. Brecciation occurred after the Wernecke Supergroup was fully lithified, deformed, and locally metamorphosed. The breccia zones were generated by forceful explosions of volatile-rich fluids within the crust. The source of the fluids is uncertain, but may be related to igneous intrusions at depth. Rapid expansion of the fluids shattered large volumes of country rock, mainly sedimentary rocks of the Wernecke Supergroup, and dioritic to syenitic rocks of the Bonnet Plume River intrusions. In the central parts of the breccia zones, fragments underwent considerable motion, and in some cases became rounded from abrasion. Venting of brecciated rock and fluid is considered likely, but surface deposits are nowhere preserved. At one locality, large blocks of country rock foundered into open space near the top of a breccia zone, forming a fallback megabreccia. Faulting may have been active concurrently with brecciation. Breccia fragments are cemented together by hematite, quartz, carbonate, chlorite, feldspar, mica, and other minerals. In most cases, clasts and wallrocks were hydrothermally altered, leading to metasomatic growth of secondary minerals including flecks of hematite or rhombs of dolomite. Widely disseminated earthy hematite and local potassic alteration in the breccia clasts resulted in color changes from original drab hues of gray and brown to striking pink and red. Clasts with embayments rimmed with secondary minerals such as specular hematite are evidence for the dissolution of clasts or their diagenetic cements by hydrothermal fluids. The main phase of brecciation and metasomatism occurred at ca. 1.6 Ga, as indicated by a 15955 Ma U-Pb date on titanite. Subsequent minor hydrothermal events related to emplacement of the Hart River intrusions and Bear River dykes occurred at 1382.87.4 Ma (U-Pb rutile) and ca. 1270 Ma (U-Pb baddeleyite), respectively. Mineralized breccias at and near the Olympic Dam deposit in South Australia mineralogically and texturally resemble, and have nearly the same age as, the Wernecke Breccias. These similarities suggest that both breccia provinces developed from related systems of hydrothermal activity, and provide additional evidence for models linking the cratons of North America and Australia in Proterozoic time.</p></div><table style="margin-bottom: 1em" border="0" cellpadding="3" class="not_ep_block"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Additional Information:</th><td valign="top" class="ep_row">The definitive version is available online at http://www.sciencedirect.com/</td></tr><tr><th valign="top" class="ep_row">Keywords:</th><td valign="top" class="ep_row">Proterozoic; Yukon; Rodinia; Breccia; Geochronology; Continental reconstructions</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/260100.html">260000 Earth Sciences > 260100 Geology</a></td></tr><tr><th valign="top" class="ep_row">Collections:</th><td valign="top" class="ep_row">UNSPECIFIED</td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">1819</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Mrs Katrina Keep</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">04 Sep 2007</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">23 Jan 2008 15:49</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=1819;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=1819">item control page</a></p> </td></tr></table> </div> <!-- InstanceEndEditable --></td> </tr> <tr> <td><!-- #BeginLibraryItem "/Library/footer_eprints.lbi" --> <table width="795" border="0" align="left" cellpadding="0" class="footer"> <tr valign="top"> <td colspan="2"><div align="center"><a href="http://www.utas.edu.au">UTAS home</a> | <a href="http://www.utas.edu.au/library/">Library home</a> | <a href="/">ePrints home</a> | <a href="/contact.html">contact</a> | <a href="/information.html">about</a> | <a href="/view/">browse</a> | <a href="/perl/search/simple">search</a> | <a href="/perl/register">register</a> | <a href="/perl/users/home">user area</a> | <a href="/help/">help</a></div><br /></td> </tr> <tr><td colspan="2"><p><img src="/images/eprints/footerline.gif" width="100%" height="4" /></p></td></tr> <tr valign="top"> <td width="68%" class="footer">Authorised by the University Librarian<br /> © University of Tasmania ABN 30 764 374 782<br /> <a href="http://www.utas.edu.au/cricos/">CRICOS Provider Code 00586B</a> | <a href="http://www.utas.edu.au/copyright/copyright_disclaimers.html">Copyright & Disclaimers</a> | <a href="http://www.utas.edu.au/accessibility/index.html">Accessibility</a> | <a href="http://eprints.utas.edu.au/feedback/">Site Feedback</a> </td> <td width="32%"><div align="right"> <p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><img src="http://www.utas.edu.au/shared/logos/unioftasstrip.gif" alt="University of Tasmania Home Page" width="260" height="16" border="0" align="right" /></a></p> <p align="right" class="NoPrint"><a href="http://www.utas.edu.au/"><br /> </a></p> </div></td> </tr> <tr valign="top"> <td><p> </p></td> <td><div align="right"><span class="NoPrint"><a href="http://www.eprints.org/software/"><img src="/images/eprintslogo.gif" alt="ePrints logo" width="77" height="29" border="0" align="bottom" /></a></span></div></td> </tr> </table> <!-- #EndLibraryItem --> <div align="center"></div></td> </tr> </table> </body> </html>