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Detrital Zircon Geochronologic Tests of the SE Siberia-SW Laurentia Paleocontinental Connection

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Detrital Zircon Geochronologic Tests of the SE Siberia-SW Laurentia Paleocontinental Connection Stephan Mueller Spec. Publ. Ser., 4, 111–116, 2009 www.stephan-mueller-spec-publ-ser.net/4/111/2009/ Special © Author(s) 2009. This work is distributed under Publication the Creative Commons Attribution 3.0 License. Series Detrital zircon geochronologic tests of the SE Siberia-SW Laurentia paleocontinental connection J. S. MacLean1, J. W. Sears1, K. R. Chamberlain2, A. K. Khudoley3, A. V. Prokopiev4, A. P. Kropachev5, and G. G. Serkina3 1University of Montana, Missoula, Montana 59812, USA 2University of Wyoming, Laramie, Wyoming 82070, USA 3St. Petersburg State University, Geological Department, University nab. 7/9, St. Petersburg, 199034, Russia 4Diamond and Precious Metal Geology Institute SB RAS, Lenin Avenue 39, Yakutsk, 677980, Republic Sakha (Yakutia), Russia 5All Russian Geological Research Institute (VSEGEI), Sredniy Prospect 74, St. Petersburg, 199106, Russia Abstract. Strikingly similar Late Mesoproterozoic strati- Frost et al., 1998; Ernst et al., 2000). Because of its large graphic sequences and correlative U-Pb detrital-zircon ages size and rich geological and paleontological heritage, the may indicate that the Sette Daban region of southeastern correct reconstruction of the Siberian-North American cra- Siberia and the Death Valley region of southwestern North ton would constrain numerous ancillary problems in Earth America were formerly contiguous parts of a Grenville fore- science, ranging from the origin and dispersal of metazoans land basin. The Siberian section contains large numbers (e.g. Bowring et al., 1993) to the long-term behavior of the of detrital zircons that correlate with Grenville, Granite- magnetic field (e.g. Kirschvink et al., 1997). Rhyolite, and Yavapai basement provinces of North Amer- The reconstruction of Sears and Price (2003) tightly fits ica. The sections in both Siberia and Death Valley exhibit the eastern Siberian craton against the western North Ameri- west-directed thrust faults that may represent remnants of can craton, and connects several Proterozoic piercing points a Grenville foreland thrust belt. North American detrital- between the two cratons (Fig. 1). The reconstruction aligns zircon components do not occur in Siberian samples above a hingelines and Neoproterozoic isopachs of the Sette Da- ∼600 Ma breakup unconformity, suggesting that rifting and ban basin of southeastern Siberia and the southwestern continental separation blocked transfer of clastic sediment Cordilleran miogeocline. It predicts that the Sette Daban between the cratons by 600 Ma. Faunal similarities suggest, basin of Siberia (Khudoley et al., 2001) was contiguous with however, that the two cratons remained within the breeding Death Valley. We undertook joint Russian-American excur- ranges of Early Cambrian trilobites and archeocyathans. sions to Sette Daban and Death Valley to compare the lithos- tratigraphy of these basins, and collected specimens for de- trital zircon U-Pb age dating. We separated detrital zircons from sandstone samples and used standard techniques to U- 1 Introduction Pb date them at the Stanford University-US Geological Sur- Close similarities in Siberian and North American base- vey SHRIMP facility and at the LAICPMS facility at Wash- ment provinces suggest that these cratons may have occu- ington State University. We analyzed selected grains at both pied contiguous parts of a Proterozoic supercontinent be- facilities and found that the two techniques gave equivalent fore the Siberian craton drifted away to become embedded in Pb-Pb ages at the 2-sigma confidence level. Our conclusions the Eurasian landmass. For nearly 30 years geologists have, are based on 780 detrital-zircon grains with Pb-Pb ages that however, disagreed upon the exact linkages of these cratons, were <10% discordant. See MacLean (2007) for full tabula- and have published a bewildering array of Proterozoic con- tions of our geochronological data. tinental reconstructions (Sears and Price, 1978, 2003; Hoff- Our results suggest that matching sequences of Mesopro- man, 1991; Condie and Rosen, 1994; Rainbird et al., 1998; terozoic strata in Sette Daban and Death Valley may have been deposited within a single intracratonic basin. Our re- sults further suggest that the basin may have rifted in Late Correspondence to: J. W. Sears Neoproterozoic time, after which detrital zircons did not ([email protected]) cross between the Siberian and North American cratons. Published by Copernicus Publications on behalf of the European Geosciences Union. 112 J. S. MacLean et al.: Detrital zircon geochronologic tests of paleocontinental connection X MLS-1 site >2.5 Ga SIBERIA MSL-1 Detrital Zircon Sources? Transitional Grenville fault 5 SIBERIA Crust 2.0-1.8 Ga Neoproterozoic isopach, km >2.5 Ga >2.5 Ga Early Paleozoic isopach trend 4 GRAN-RHY W. YAVAPAI GRENVILLE EXOTIC MAZATZAL MLS-1 >2.5 Ga 3 1.3-1.0 Ga Basin NORTH AMERICA 2 Number 5 100 KM 4 2 1.9-1.7 Ga 1 3 1 1.4 Ga RELATIVE PROBABILITY RELATIVE N. American sources ? Enlarged below 0 800 1200 1600 2000 2400 2800 Ma Age 207Pb/206Pb 2 1 IBEX BASIN N AMERICA 135 E SIBERIA Belaya River 2 4 3 CORDILLERAN MIOGEOCLINAL HINGE DEATH VALLEY 60 N 1 X ALDAN RIVER 3 4 BRIGHT ANGEL FAULT 1.7 GA RHYOLITE-QUARTZITE BELT 2 YAVAPAI 4 3 SETTE-DABAN TROUGH MAYA RIVER North edge of preserved MAZATZAL 1.3 -1.0 Ga 1.4 GA Detrital Zircon Sources? diabase- W GRANITE- ULKAN OKHOTSK engorged basin RHYOLITE 1.7-1.73 Ga MASSIF? PROVINCE PRIKOLYMA AND OMOLON TERRANES ? 100 km GRENVILLE PROVINCE 1.3-1.0 GA Fig. 1. Proterozoic connection between Siberian and North American cratons after Sears and Price (2003). Death Valley restores against Sette Daban basin of Siberia. Gray arrows show possible transport of sediment down rift from Grenville, Granite-Rhyolite, and Yavapai basement provinces to Sette Daban basin, where correlative detrital zircons were found, for example in Siberian sample MLS-1 (inset). Small black arrows identify trough axis at margin between reconstructed continents. Death Valley and White-Inyo positions (black spots) restored after Levy and Christie-Blick (1993). Sette Daban isopachs after Khudoley et al. (2001). Transitional crust shown in inset after Khudoley and Prokopiev (2007). 2 Lithostratigraphic matches dolomite, capped by remarkably similar beds of branching stromatolites. The overlying Bik Formation of the lower The Mesoproterozoic basins of Sette Daban and Death Valley Kerpyl Group matches the upper part of the Crystal Spring contain remarkably similar lithostratigraphic sequences, al- Formation. Each overlies a karstified surface and locally though the Sette Daban section is approximately three times includes dm-thick beds of distinctive conglomerate at the thicker (Fig. 2). The pertinent part of the Siberian section base, with pebbles of blue quartz and dolomite, succeeded includes, from the base up, the Aimchan, Kerpyl, Lakhanda, by blocky-fracturing, trough-crossbedded quartzite, and red and Uy groups (Khudoley et al., 2001). Its North American shale with thin white quartzite beds. counterpart comprises, from the base up, the Crystal Spring, The upper Kerpyl and Lakhanda groups meticulously Beck Spring, and lower Kingston Peak (KP1 of Prave, 1999) match western facies of the Beck Spring Formation that formations of the Pahrump Group (Link, 1993). are exposed in the Ibex Hills of southwest Death Valley. The Aimchan Group closely resembles the lower part Both sections consist of five or six variegated siliciclastic- of the Crystal Spring Formation; both have basal trough- dolomite cycles that are each made up of numerous smaller crossbedded sandstone and conglomerate overlain by red cycles. In each section, a typical cycle begins with yellow- shale and pinkish-orange weathering, cherty, stromatolitic weathering, grey shale, followed in order by yellow or Stephan Mueller Spec. Publ. Ser., 4, 111–116, 2009 www.stephan-mueller-spec-publ-ser.net/4/111/2009/ J. S. MacLean et al.: Detrital zircon geochronologic tests of paleocontinental connection 113 orange-weathering laminated dolomite, grey microlaminated dolomite, and black, bituminous, microlaminated and stro- matolitic dolomite. The Death Valley section includes mica- Neoproterozoic 1.0 -0.95 Ga ceous and feldspathic sandstone at the bases of some cycles. Yudoma (syn-dep. sills) The eastern facies of both sections include thick dolomite 100 m UN NEOP Grey sh BR characterized by solution-collapse breccias and distinctive 2– CO & ss Uy EA 3-m tall microbial mounds with flanking roll-up slump struc- NF RO KUP tures and breccias. This facies characterizes the Beck Spring OR T Formation in the Alexander Hills and Kingston Range of the G MI Variegated TY Death Valley region (Abolins et al., 2000). siliciclastic S The Lakhanda Group grades upward into the Uy Group, dolomite cycles 2 KP E a kms-thick grey shale and sandstone succession. The Beck Lakhanda Spring Formation passes up into similar grey shale and sand- V stone of the transition beds of the lower Kingston Peak 1025 Ma KP 1 KP Formation (KP1) that Prave (1999) considers related to the Tsip (Pb-Pb) Beck Spring depositional cycle. Both the Siberian and west- Black bituminous 1043 Ma ern Death Valley sections were locally deformed by west- dolomite breccia Mal directed thrust faults and folds prior to Late Neoproterozoic. (Pb-Pb) These were reported by Khudoley and Guriev (2003) in the Grey sh & Beck Spr Beck Sette Daban basin. We observed west-directed thrusts within orange dol Mu Kerpyl the Beck Springs-KP1 section in the Ibex Hills that are over- Red sh & lain with angular unconformity by Kingston Peak diamictite white ss P ahrump Group (KP2 of Prave, 1999). These structures may record contrac- <1.08 Ga (dz) Bik tion in a Grenville foreland basin (e.g. Sears and Price, 2003; Congl Spr Xal Up Timmons et al., 2005). Stromatolitic The Sette Daban and Death Valley Mesoproterozoic sec- dolomite 1.08 Ga tions are overlain above a breakup unconformity by 10– sill Svetlyi 15 km thicknesses of Late Neoproterozoic to Triassic de- posits that accumulated response to subsidence of passive Trough xbed ss Lower Xal Spr Xal Lower continental margins (Evenchick et al., 2007; Khudoley and Aimchan Guriev, 2003).
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