Stratigraphic trends in detrital zircon geochronology of upper Neoproterozoic and Cambrian strata, Osgood Mountains, Nevada, and elsewhere in the Cordilleran miogeocline: Evidence for early Cambrian uplift of the Transcontinental Arch Gwen M. Linde1, Patricia H. Cashman1, James H. Trexler, Jr.1, and William R. Dickinson2 1Department of Geological Sciences and Engineering, University of Nevada, Reno, Nevada 89557, USA 2Department of Geosciences, University of Arizona, Tucson, Arizona 85721-0077, USA ABSTRACT a funda mental feature of the lower Paleozoic strata that reflect initial rifting (e.g., Poole Laurentian craton. It was fi rst recognized from et al., 1992; Yonkee et al., 2014, and references U-Pb detrital zircon geochronology pro- broad structures and Phanerozoic sedimentation therein). These strata are mostly quartzite, with vides insight into the provenance of the patterns in the mid-continent (Fig. 1) (Keith, some siltstone, argillite, and phyllite; carbon- upper Neoproterozoic–lower Cambrian 1928). Sloss (1963, 1988) noted the deposition ate intervals are present in some locations (e.g., Osgood Mountain Quartzite and the upper of the middle and lowermost upper Cambrian Stewart, 1991; Poole et al., 1992). These units Cambrian–lower Ordovician Preble Forma- Sauk II sequence onlapping from the craton have been correlated across a broad region of tion in the Osgood Mountains of northern margin onto the Transcontinental Arch (Fig. 1). western North America (e.g., Poole et al., 1992). Nevada (USA). We analyzed 535 detrital zir- Carlson (1999) proposed, instead of a discrete Previous detrital zircon studies of upper Neo- con grains from six samples of quartz arenite arch, a platform, a discontinuous zone with proterozoic–lower Paleozoic passive margin by laser ablation–multicollector–inductively highs and lows and fl anking basins that give the strata record similar changes in detrital zircon coupled plasma–mass spectrometry. The appearance of an arch (Fig. 1). age peaks and groups and therefore possibly detrital zircon age data of these Neo protero- In recent U-Pb detrital zircon geochronol- similar changes in provenance. Zircon ages in zoic–lower Paleozoic passive margin units ogy studies, researchers have proposed the upper Neoproterozoic–lower Cambrian strata in record a provenance change within the Transcontinental Arch as a barrier to sediment Utah (Lawton et al., 2010; Gehrels and Pecha, Osgood Mountain Quartzite. Comparison delivery from the central Laurentian craton to its 2014; Yonkee et al., 2014), Idaho (Yonkee et al., of these data with the work of others reveals western margin in early Paleozoic time (Amato 2014), and Nevada (Gehrels and Pecha, 2014; that this change in provenance occurred in and Mack, 2012; Gehrels and Pecha, 2014; Yonkee et al., 2014) change from predomi- correlative strata throughout an east-west Yonkee et al., 2014). Amato and Mack (2012) nantly Mesoproterozoic in the older strata to transect of the Great Basin. From latest Neo- documented evidence from the Bliss Sandstone upper Mesoproterozoic–Paleoproterozoic in the proterozoic through earliest Cambrian time, for the existence of the Transcontinental Arch younger strata. most grains were shed from the 1.0–1.2 Ga by at least the late Cambrian; they explained The only previous detrital zircon study of the Grenville orogen. After that time, drain- the differences in detrital zircon populations Osgood Mountain Quartzite was that of Gehrels age patterns changed and most grains were between the Tapeats Sandstone west of the arch and Dickinson (1995), who sampled from the derived from the 1.6–1.8 Ga Yavapai and and the Cambrian sandstones east of the arch by upper part of the formation. The Preble Forma- Mazatzal provinces; very few grains from the the uplift of the arch possibly as early as early tion has never been the subject of a published Grenville orogen were found in the younger Cambrian time. Gehrels and Pecha (2014) esti- detrital zircon study. strata. We suggest that this shift records the mated the uplift of the arch by early Cambrian We dated detrital zircons from three localities uplift, in early Cambrian time, of the Trans- time. Others have noted the possibility of early of the upper Neoproterozoic–lower Cambrian continental Arch. Our data also support our Cambrian uplift of the arch as the cause of the Osgood Mountain Quartzite and three locali- interpretation that the Osgood Mountain differences in detrital zircon age peaks and ties of the upper Cambrian–lower Ordovician Quartzite and the Preble Formation are cor- groups in passive margin strata in Utah (Yonkee Preble Formation in the Osgood Mountains relative to other contemporaneous passive et al., 2014). and near Edna Mountain, north-central Nevada margin strata in western Laurentia. Upper Neoproterozoic–lower Cambrian silici- (Fig. 2B; Table 1). We show that the detrital clastic rocks on the western Laurentian passive zircon ages shift within the Osgood Moun- INTRODUCTION margin record sedimentation that initiated after tain Quartzite; detrital zircons from the older rifting and continental separation (e.g., Stewart, samples are predominantly Mesoproterozoic, The Transcontinental Arch, a region of 1972; Poole et al., 1992). These passive mar- while detrital zircons from the younger sample, uplift that extends from the southwestern U.S. gin rocks were deposited on a discontinuously and all of the Preble Formation samples, are to south-central Ontario, Canada (Fig. 1), is exposed succession of diamictite and vol canic predominantly upper Mesoproterozoic–Paleo- Geosphere; December 2014; v. 10; no. 6; p. 1402–1410; doi:10.1130/GES01048.1; 7 fi gures; 1 table; 1 supplemental fi le. Received 4 March 2014 ♦ Revision received 1 August 2014 ♦ Accepted 10 August 2014 ♦ Published online 7 October 2014 1402 For permission to copy, contact [email protected] © 2014 Geological Society of America Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/10/6/1402/3338869/1402.pdf by guest on 28 September 2021 Detrital zircon geochronology of the Osgood Mountain Quartzite and Preble Formation in Nevada 50N passive margin section from the northwest U.S. 140W0 100W100W 60W to Sonora, Mexico (e.g., Lawton et al., 2010; SU CordilleranCordilleran HE Gehrels and Pecha, 2014; Yonkee et al., 2014). PassivePassive MarginMargin In contrast, the 1.8–1.6 Ga Yavapai-Mazatzal CanadaCanada Peri-LaurentianPeri-Laurentian and 1.48–1.34 Ga mid-continent granite rhyo- USA Peri-GondwananPeri-Gondwanan CORD WY lite provinces within the North America craton (720–400(720–400 Ma)Ma) (Fig. 1) were the dominant sediment sources Grenville orogen higher in the passive margin section (e.g., (1.2–1.0(1.2–1.0 Ga)Ga) ? ? Lawton et al., 2010; Gehrels and Pecha, 2014; 1.48–1.341.48–1.34 GaGa ? MMagmaticagmatic ProvProv ? NorthNorth Yonkee et al., 2014). The Osgood Mountain Quartzite and Preble Mazatzal/YavapaiMazatzal/Yavapai ? (1.8–1.6(1.8–1.6 Ga)Ga) ? Formation in northern Nevada have been inter- Trans-HudsonTrans-Hudson ? APP 30N (2.0–1.8(2.0–1.8 Ga)Ga) USAU preted as passive margin strata; they both have ? ArcheanArchean (>2.5(>2.5 GaGa)) MexicoM co ? an interesting position and tectonic and meta- OA morphic histories. They are far to the west of Transcontinental Arches most other passive margin units and are over- Carlson (1999) thrusted by both the Roberts Mountains alloch- Sloss (1988) 1000 kmkm thon and the Golconda allochthon (Burchfi el Keith (1928) et al., 1992; Poole et al., 1992). The Preble Formation is metamorphosed to greenschist ? Mazatzal/Yavapai ? Boundary facies, and has refolded folds (Cashman et al., 2011); it has been interpreted as being in con- formable stratigraphic succession with the Figure 1. Location of the main age provinces in North America that are potential source Osgood Mountain Quartzite (Fig. 3), based on terranes for the late Neoproterozoic–early Cambrian western Laurentian passive margin. map relationships and compositional similarity Hypothesized transcontinental arches are superimposed (Keith, 1928; Sloss, 1988; Carlson, of an upper member of the Osgood Mountain 1999). WY—Wyoming province; HE—Hearn province; SU—Superior province; CORD— Quartzite to the Preble Formation (Hotz and Cordilleran; APP—Appalachian; OA—Ouachita-Marathon. Figure is after Gehrels et al. Willden, 1964). (2011) and adapted from Anderson and Morrison (1992), Bickford et al. (1986), Hoffman Structurally, the Osgood Mountains comprise (1989), Burchfi el et al. (1992), Bickford and Anderson (1993), Van Schmus et al. (1993), a large, northeast-trending anticline with a sub- Dickinson and Lawton (2001), and Dickinson and Gehrels (2009). horizontal axis (Fig. 2B). The Preble Formation is exposed only on the fl anks of the anticline proterozoic. Coeval passive margin strata in margin units? (4) If a consistent stratigraphic (Fig. 2B). Late Paleozoic rocks are thrust over other studies throughout the Great Basin (e.g., pattern of detrital zircon ages exists in all Neo- the anticline in the northern and western parts of Lawton et al., 2010; Gehrels and Pecha, 2014; proterozoic–Cambrian sections, what caused a the range, and the southern extent of the Osgood Yonkee et al., 2014) show the same shift in ages. widespread change in detrital zircon ages with Mountains is overlain by Cenozoic andesite This suggests that a change in provenance in time in these units? fl ows (Fig. 2B) (Hotz and Willden, 1964). The these passive margin strata is widely recorded in Osgood Mountain Quartzite and Preble Forma- this region of western Laurentia. GEOLOGIC SETTING tion are primarily exposed in the central and In this paper we present new U-Pb zircon southern portions of the range (Fig. 2B). ages from the Osgood Mountain Quartzite and The North American craton contains several The Osgood Mountain Quartzite consists the Preble Formation. The dates were obtained Proterozoic and Archean age provinces, thus mostly of fi ne- to medium-grained quartz using laser ablation–multicollector–inductively providing geographically distinguishable crustal arenite , with some silty and shaly beds (Fig.