Multistage Cenozoic Extension of the Albion–Raft River–Grouse Creek Metamorphic Core Complex: Geochronologic and Stratigraphic Constraints

Home , Black Pine Mountains, Raft River Mountains

Investigations of North America as EarthScope Reaches Its Maturity themed issue

Multistage Cenozoic extension of the Albion–Raft River–Grouse Creek metamorphic core complex: Geochronologic and stratigraphic constraints

Alexandros Konstantinou1, Ariel Strickland2, Elizabeth L. Miller1, and Joseph P. Wooden3,1 1Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305, USA 2Department of Geoscience, University of Wisconsin, 1215 W. Dayton Street, Madison, Wisconsin 53706, USA 3U.S. Geological Survey, Menlo Park, California 94025, USA

ABSTRACT Albion–Raft River fault system, began to they are typically intruded by synextensional develop along the eastern side of the ARG plutons and bound by detachment faults associ- Despite numerous studies on the structural metamorphic core complex ca. 13.5 Ma, syn- ated with zones of very high ductile extensional evolution of metamorphic core complexes, chronous with footwall cooling and uplift strains (e.g., Coney, 1980; Wernicke, 1981; Arm- there is still little consensus on the set and between 13.5 and 7 Ma recorded by apatite strong, 1982; Miller and Gans, 1989). Regions sequence of processes that bring deep levels fi ssion track ages. The evolution of sedi- fl anking metamorphic core complexes typically of the crust to the surface during extension. ment sources in the Raft River Basin help expose supracrustal rocks, including Cenozoic This problem is partially related to the fact defi ne three phases of Miocene tectonism. volcanic and sedimentary sequences that record that core complexes expose polydeformed (1) Between 13.5 and 10.5 Ma, rapid slip on the fi nal exhumation of the complexes (e.g., rocks, the history of which has been chal- the Albion fault, which rooted into a ductile- Eberly and Stanley, 1978; Dickinson, 1991; lenging to decipher. New geochronological brittle transition zone represented by the Davis et al., 2004; Miller and Gans, 1989; Miller and structural data combined with existing Raft River detachment, exhumed Paleozoic et al., 1999; Colgan and Metcalf, 2006; Colgan data provide improved insight into the Ceno- strata that, together with Miocene volcanic and Henry, 2009). zoic extensional evolution of the Albion–Raft rocks, sourced the basin. (2) Between 10.5 Despite numerous studies on the structural River–Grouse Creek (ARG) metamorphic and 8.2 Ma, continued slip resulted in a topo- evolution of metamorphic core complexes, there core complex. The Cenozoic extensional graphic depression fi lled with volcanic rocks is still little consensus on the set and sequence history of the core complex can be divided and detritus derived from footwall metamor- of lower crustal processes that exhume the deep into several distinct stages based on the geo- phic and crystalline rocks as well as prior levels of the crust in an extensional tectonic set- chronology and structure of igneous and sources. (3) After 8.2 Ma, the sedimentary ting, and how these processes are refl ected in the metamorphic rocks in the lower plate of the basin was cut, rotated, and repeated by a surface geology (Fig. 2). The concept of large- complex combined with the geochronology set of younger north-south–striking normal offset low-angle normal faults was fi rst used by and regional geologic context of sedimentary faults that extended the basin in an east-west Wernicke (1981) to explain the northern Snake and volcanic rocks fl anking the complex. Ini- direction, structurally uplifting the basin Range and other core complex detachment tial volcanism and plutonism was Eocene age sedi ments to erosion. These younger faults faults. Since then, this model has been widely (42–34 Ma), related to a regional southward- die out to the south and minimally displace used to explain the geometry of extensional younging magmatic event. The development the fault system that bounds the metamor- fault systems and core complexes, both in sur- of high-temperature (sillimanite grade) meta- phic core of the Raft River Mountains. face exposure and in seismic refl ection profi les. morphic fabrics and mineral assemblages The Cenozoic evolution proposed for the Motion on low-angle normal faults is mechani- in footwall rocks was mostly Oligocene (ca. ARG metamorphic core complex indicates cally diffi cult to explain based on rock physics 32–25 Ma), synchronous with the diapiric that the formation of Oligocene granite- experiments and the fact that most seismically rise and intrusion of evolved plutons to mid- cored gneiss domes and their high-temper- active normal faults have steep (>30°) dips (e.g., crustal depths (~10–15 km), formed by par- ature metamorphic carapace and overlying Jackson and White, 1989; Thatcher and Hill, tial melting and remobilization of the deeper detachments, are distinctly older (ca. 10 Ma), 1991; Collettini and Sibson, 2001; Collettini and crust. There is no evidence for associated vol- and thus unrelated to the younger exhuma- Barchi, 2002). The origin of the high-strain duc- canism or basin development at the surface tion by high-angle faulting. tile extensional fabrics and mylonites associated during this time span. The metamorphic and with metamorphic core complex detachment plutonic rocks of the core complex appar- INTRODUCTION faults is also a matter of debate. The low-angle ently remained at depth for ~10–12 m.y. until normal fault model explains the mylonitic fab- the Middle Miocene (ca. 14 Ma), when they Metamorphic core complexes are structural rics as forming in extensional shear zones that were exhumed by Basin and Range faulting. culminations of exhumed metamorphic and penetrate the deep crust and bound a relatively Detrital zircon studies of continental basin igneous rocks that occur in extensional settings. rigid footwall block (e.g., Wernicke, 1981; Wer- sediments demonstrate that the synexten- They were fi rst described in the Basin and Range nicke and Axen, 1988; Wells et al., 2000; Fig. 2). sional Raft River Basin, bounded by the province of the western U. S. (Fig. 1A), where An alternative explanation of these fabrics is

Geosphere; December 2012; v. 8; no. 6; p. 1429–1466; doi:10.1130/GES00778.1; 14 ﬁ gures; 4 tables. Received 19 December 2011 ♦ Revision received 8 August 2012 ♦ Accepted 21 August 2012 ♦ Published online 16 November 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021

Konstantinou et al. Relative probability Relative N S ) error are excluded. are ) error σ l positioning system (GPS) velocity vectors. ported ages with >5% (1 cks of Mesozoic and Cenozoic age. Locations Stacked relative probability Age of igneous rocks (Ma) diagrams of the age Cenozoic magmatism at six latitude intervals border to southern Nevada, compiled from NAVDAT NAVDAT to southern Nevada, compiled from border B 0 10203040506070 ° ° ° 7 3 9 3 3 3 – °– ° °– 9 1 7 Lat. 50°–46° 43°–41° 39°–37° 3 39°–37° 46°–43° 41°–39° 4 41°–39° 37°–33° 3 37°–33°

0°N

45°N 4

Km 2.0–0.6 Ma 2.0–0.6 Laramide, Rocky Mts. 55–44 Ma Absaroka Volcanics

Age progression of siliceous caldera complexes, Snake River Plain Sevier Metamorphic core complex GPS vel. vector length = 3 mm/yr 110°W Age propagation of Cenozoic magmatism thrust belt plateau

Colorado 10.5– Ma 4

8.5 Ma

<29.5 Ma

6.6–4.

2 Bitterroot

100 10.2–9.

l 52–45 Ma Snake River Plain River Snake a a Eocene–present Cascade magmatism Mesozoic– Paleocene arc–batholith 12–2 Ma 16–12 Ma 55–45 Ma h ARG Challis Volcanics Challis Volcanics C

.5– Volcanic rocks Volcanic 0200400

8.5 Ma UT

NV Pioneer River Idaho

Priest P .7– Ma Ma

B Batholith 12

10.5

Range

Snake <43.4

6.0 Ma Shuswap

a <3

ID 120°W Mts.

Ruby

2.8 M

14.5– 1 NV OR

– <29.5 Ma

<23.2 Ma 17.0 Ma 16.6 5 Ma 1 < Basin

Complex a and Range 58–45 Ma Okanogan

Colville Igneous 16.6– Mts. Basalts 15.6 M Funeral

Columbia River

°W

125

0°W 12 Sierra Nevada Approximate Mz. batholith eastern limit of Cascade magmatism

°N A

45°N 40°N 35 (North American Volcanic and Intrusive Rock Database; www.navdat.org/). Altered rocks (based on geochemistry) and rocks with re (based on geochemistry) and rocks rocks Altered and Intrusive Rock Database; www.navdat.org/). Volcanic American (North (B) Relative probability diagrams of the ages of Cenozoic (65–17 Ma) igneous rocks at six latitude intervals from the Canadian at six latitude intervals from diagrams of the ages Cenozoic (65–17 Ma) igneous rocks (B) Relative probability Figure 1. (A) Shaded relief map of the western United States highlighting the northern Great Basin and exposures of magmatic ro Basin and exposures map of the western United States highlighting northern Great 1. (A) Shaded relief Figure by blue globa is recorded deformation of the Basin and Range province Present-day shown in gray. complexes are metamorphic core

1430 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

Extensional gneiss domes Low-angle normal faults ing data and combining it with new data from 60 km 60 km the ARG metamorphic core complex, where the timing of Cenozoic events is now documented brittle crust with greater clarity (Figs. 1 and 3). Speciﬁ cally,

20 km DBTZ we compare the timing of magmatic and defor-

20 km DBTZ 60 km

40 km ductile crust ductile crust mational events in the lower plate of the ARG metamorphic core complex to the faulting and moho depositional history of the ﬂ anking Raft River Supracrustal extension: regional: 10 km horizontal extension, β = 1.17 Basin (Fig. 3). Using these data, we demonstrate local: 10 km horizontal extension across 10 km, β = 2 moho that the Cenozoic extensional history of ARG 20 km top of gneiss 70 km dome (DBTZ) 60 km of horizontal slip, metamorphic core complex is both multistage 20 km of vertical throw 60 km supracrustal extension β= 2 and polygenetic. local faulting brittle crust 120 km BACKGROUND

34 km magmatic addition/melting distributed stretching and flow shear zone Regional Cenozoic Tectonic and Magmatic

30 km regional total: 20 km total horizontal extension β = 1.33 Setting of the ARG local: 20 km total horizontal extension β = 3 30 km sedimentary basin top of gneiss dome 80 km The northern Basin and Range province of the western U.S. (Fig. 1A) is a broad, younger brittle normal active continental rift, characterized by north- crust fault ward-striking normal fault blocks formed by

30 km east-west extension, a lower crust with subhori- zontal seismic refl ectivity, and a sharp Moho at Figure 2. Simplifi ed depiction of core complex models, schematically illustrating the differ- a uniform depth of 28–32 km (e.g., Klemperer ences between the amount of horizontal extension represented by a diapirically driven gneiss et al., 1986; Hauser et al., 1987; Catchings and dome (emplaced in an extensional tectonic setting) versus that represented by the unroofi ng of Mooney, 1991; Catchings, 1992; Gashawbeza deep metamorphic rocks by slip along a low-angle normal fault. DBTZ—ductile-brittle tran- et al., 2008). These present-day characteristics sition zone. Cross-sectional area is preserved. These two end-member models also emphasize are the result of a protracted history of both the implications of these two models for determining preextensional crustal thickness. magmatism and deformation, the details of which elusive and controversial. Following the end of regional folding and thrust faulting in that they form at the top of zones of crustal fl ow ogy and thermochronology to argue that many the latest Cretaceous–earliest Cenozoic (Sevier and diapirism, aided by elevated geotherms and of the high-strain fabrics in the Grouse Creek and Laramide orogenies; e.g., Armstrong, the presence of partial melts (e.g., Rehrig and and Albion Mountains are related to alternating 1982; Burchfi el et al., 1992; DeCelles, 1994, Reynolds, 1980; Miller et al., 1988; MacCready periods of contraction and extension in Creta- 2004), Cenozoic volcanic rocks erupted across et al., 1997; Foster et al., 2001; Whitney et al., ceous–Eocene time. the northern Basin and Range; they describe a 2004; Teyssier et al., 2005; Rey et al., 2009) Unraveling the exact timing of events in core prominent north to south younging pattern (e.g., (Fig. 2). In these views, high-strain fabrics and complexes is important because the history of Armstrong and Ward, 1991; Best and Chris- mylonites develop between the fl owing part these deep crustal rocks forms the basis for our tiansen, 1991; Christiansen and Yeats, 1992; of the crust, i.e., the lower plate, and its brittle understanding of the processes that brought Gans et al., 1989; Figs. 1A, 1B). The onset of cover, the upper plate, and represent the ductile- them to the surface and the nature of the tran- magmatism began in southern Canada, northern brittle transition zone of the crust. sition from regional shortening to extension in Idaho, and Montana ca. 55 Ma and migrated to In the Albion–Raft River–Grouse Creek the North American Cordillera. In addition, the southern Nevada by ca. 20 Ma (Christiansen and (ARG) complex, the age of high-strain fabrics evolution and kinematic history of core com- Yeats, 1992; Armstrong and Ward, 1991; Best and the depth to which they have developed plexes have a critical effect on our ability to bal- and Christiansen, 1991; Figs. 1A, 1B). Based on in the crust are debated. Early studies in the ance structural sections and calculate amounts geochemistry, these magmas are generally inter- ARG metamorphic core complex by Armstrong of extension across the Basin and Range (Fig. preted as derived from mafi c parent magmas (1968a), Compton et al. (1977), Miller (1980), 2). Specifi cally, the two end-member models in that were generated by the melting of hydrated and Todd (1980) related the dominant, gently Figure 2 represent signifi cantly different hori- mantle. The cause of this magmatism is thought dipping, and high-strain foliation in the lower zontal strains (β-factor of 1.33 versus 2.0) and to be related to the progressive delamination plate to attenuation and extension of the crust also imply substantially different initial crustal of the shallowly dipping subducted Farallon during intrusion of Oligocene plutons. These thicknesses. The lack of consensus on how slab, inferred to have underlain the northern earlier conclusions are supported by geochrono- metamorphic core complexes form represents Basin and Range province during the Laramide logic studies (Egger et al., 2003; Strickland a challenge in terms of our ability to quanti- orogeny (ca. 80–60 Ma) (e.g., Dumitru et al., et al., 2011a, 2011b). Alternatively, studies by tatively evaluate preextensional crustal thick- 1991; Burchfiel et al., 1992; Humphreys, Wells et al. (1998, 2012), Harris et al. (2007), nesses and their implied paleoelevations, which 1995; Humphreys et al., 2003 Christiansen Hoisch et al. (2008), and Wells and Hoisch are sensitive to calculated amounts of crustal and McCurry, 2008). The southward sweep of (2008) used metamorphic pressure-tempera- extension (e.g., DeCelles, 2004; Ernst, 2010). magmatism left a landscape that had only lim- ture estimates in conjunction with geochronol- We address these questions by compiling exist- ited topographic relief and was covered by fl at-

Geosphere, December 2012 1431

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

250 km

S C N o r S d i l l e

r a N n B f o l d Cotterel Mts. 0.706 a n

line d

t h

SRP r u

s 20 Km t

ARG b n

e Albion Mts.

l t R n Figure 8

n n Jim Sage Mts. Middle Figure 6 Mt. gneiss Raft River Valley

Figure 3. Index map (inset) and Middle Mt. n generalized geologic map of Minimum extend of 32–29 Ma batholith? the Albion–Grouse Creek–Raft 30° Black River Mountains (ARG). S— Almo pluton Pine Mts.

Shuswap metamorphic core n complex; B—Bitterroot meta- IDAHO 42° UTAH n morphic core complex; R— n n n Ruby Mountain metamorphic n n n core complex; SRP—Snake n Vipoint n n River Plain. Box indicates the pluton n location of Figure 8 (modiﬁ ed n n n n 15° from Compton et al., 1977; n Raft River n Miller, 1978; Todd, 1980; Miller UTAH Mts. et al., 2008; Wells, 2009; Strick- n n n n n land et al., 2011b). n n

n 113°15′

Red Butte <8.2 Ma Cotterel Basalt pluton 8.2 Ma Upper Jim Sage Lavas Grouse Cenozoic Basin Creek Mts. Middle Tuffs of Jim Sage Figure 7 n 9.5 Ma Lower Jim Sage Lavas

Cenozoic sedimentary units n 32–25 Ma Cenozoic Plutons

n 42–34 Ma Cenozoic Plutons

Emigrant Phanerozoic metasedimentary units Detachment fault, Pass plutonic n teeth on the upper Metamorphic lower plate rocks complex plate Archean crystalline basement High-angle normal fault, ball on the Middle Mountain shear zone down thrown side Raft River shear zone 113°45′

lying volcanic rocks; this is documented by the suggests that the topographic divide of this low- 15 Ma, with rapid slip on faults in the central widespread unconformity developed at the base relief region was in the central part of the north- part of the northern Basin and Range occur- of volcanic strata across the northern Basin and ern Basin and Range during the Eocene (Henry, ring ca. 17–16 Ma (Miller et al., 1999; Stockli, Range, and by the unimpeded, channelized east- 2008), but the absolute elevation of this plateau 1999; Colgan and Metcalf, 2006; Henry, 2008; west ﬂ ow of Eocene–Oligocene ignimbrites is controversial (e.g., DeCelles, 2004; Mulch Colgan and Henry, 2009). The onset of Basin in paleovalleys (e.g., Gans et al., 1989; Henry, et al., 2006; Best et al., 2009; Henry, 2008; and Range faulting is younger toward the bor- 2008; Colgan and Henry, 2009; Van Buer et al., Ernst, 2010; Henry et al., 2011). ders of the province; rapid slip on faults began 2009; Long, 2012; Fig. 4). A compilation of Basin and Range faulting leading to the ca. 15–10 Ma in both the northwestern and caldera locations and ignimbrite ﬂ ow directions present-day topography began between 20 and northeastern parts of the province, including

1432 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021

Multistage extension of the ARG metamorphic core complex

d r

o f

a r Β C

100 km

k e c

a o

e r

M c

v Permian

Oquirrh Basin

e Pennsylvanian- phic core complex was characterized phic core

o ARG (see text). e

y ARG

e r

Pioneer e

Snake Range Snake v

t s

nts.

Ruby M Ruby

o S Mesozoic thrust Devonian-Triassic thrusts Cretaceous Cretaceous Granite Jurassic Granite Jurassic Triassic Pennsylvanian-Permian Sillurian-Mississippian Cambrian-Ordovician Proterozoic Α Cenozoic Geologic Map

Roberts Mts. and Golgonda allochthons Fold axis

100 km

Cenozoic Unconformity Cenozoic

o C Figure 4. (A) Locations of mapped traces the Cenozoic unconformity Figure digital state geologic maps of Utah (Hintze et al., 2000), obtained from Nevada (Stewart et al., 2003), Idaho (Johnson and Raines, 1996) from coded based The trace of the unconformity is color (1983). Gans and Miller (B) Paleogeologic map constructed on the age of underlying rocks. such as with mapped structures A; these data together using data cited in base map (Cenozoic extension is not on a present-day folds and faults are (ARG) metamor Creek Albion–Raft River–Grouse the around The region 2008). Blakey, outline of the Oquirrh Basin is from removed; populations in Miocene strata of th consistent with the detrital zircon of mostly Pennsylvanian and Permian rocks, by exposures

Geosphere, December 2012 1433

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

the region in and around the ARG metamorphic 1995). Late Eocene magmatism in the ARG is (Figs. 5A and 6), and the youngest is the Red core complex (e.g., Wells et al., 2000; Egger represented by the Emigrant Pass plutonic com- Butte pluton, dated as 25 Ma (Compton et al., et al., 2003, 2010; Colgan and Metcalf, 2006; plex, composed of calc-alkaline intermediate to 1977; Todd, 1980; Egger et al., 2003) (Figs. 3, Colgan et al., 2007; Fosdick and Colgan, 2008). felsic magmas (Fig. 3). The Emigrant Pass plu- 5A, and 7). The composite plutons of the Cassia tonic complex (Fig. 3) was emplaced at shallow plutonic complex have more evolved Sr and Nd Geology and Geochronology of Footwall crustal levels (5–10 km) (Egger et al., 2003) and isotopic signatures relative to the Eocene Emi- Rocks of the ARG was coeval with the eruption of felsic volcanic grant Pass plutonic complex, implying a greater rocks (Compton, 1983; Kistler and Lee, 1989; degree of crustal assimilation (Wright and The oldest rocks exposed in the ARG meta- Nutt and Ludington, 2003). To the southeast of Wooden, 1991; Strickland et al., 2011b). The morphic core complex are crystalline Archean the ARG, andesite fl ows, dacite, and rhyolite zircon crystals in the Oligocene plutons have orthogneiss, schist, and amphibolite (col- ignimbrites of the 41–39 Ma northeast Nevada Oligocene magmatic rims and ubiquitous Neo- lectively termed the Green Creek Complex), volcanic fi eld represent a comparable suite of archean cores, supporting this inference (Fig. unconformably overlain by quartzites and magmas (Brooks et al., 1995; Palmer and Mac- 5A; Egger et al., 2003; Strickland et al., 2011b). metapelites that represent the base of the pas- Donald, 2002). Based on their geochemistry However, the young zircon overgrowths have sive margin succession of the Cordillera (Fig. 3; and tracer isotope compositions, Eocene mag- light δ18O values (5.40‰ ± 0.6‰), imply- Armstrong, 1968b; Compton et al., 1977; Stew- mas incorporated variable amounts of ancient ing that they crystallized in equilibrium with art, 1980). These metasedimentary rocks are continental crust (Armstrong and Hills, 1967; mantle values (Strickland et al., 2011b). Unlike Proterozoic in age, on the basis of association Compton et al., 1977; Wright and Wooden, earlier Eocene magmas, there is no evidence of their high δ13C values (Wells et al., 1998) 1991; Egger et al., 2003). The Emigrant Pass that plutons of this age ever erupted; their and detrital zircon signatures (Link and John- plutonic complex intrudes a tilted Paleozoic intrusion spans a period of well-documented ston, 2008). Higher stratigraphic units include stratigraphic section and several normal faults, vol canic quiescence in the northern Basin and the Ordovician Pogonip Group and the Penn- which were folded during the intrusion of the Range (e.g., Armstrong and Ward, 1991; Bur- sylvanian–Permian Oquirrh Group (included in pluton (Egger et al., 2003). However, regional ton, 1997; du Bray, 2006; Fig. 1B). the Phanerozoic unit in Fig. 3). The Cambrian and local evidence for signifi cant Eocene fault- Detailed geologic mapping and geochronol- and parts of the Silurian–Devonian sections of bound sedimentary basins is generally lacking ogy of the Oligocene plutons and their contact the passive margin succession are missing from both in and around the ARG metamorphic core aureoles (Figs. 6 and 7) (Todd, 1980; Egger the ARG and have been inferred to have been complex and across the greater northern Basin et al., 2003; Strickland et al., 2011a, 2011b) pro- removed by normal faulting in the Late Creta- and Range. Exceptions include the northern vide convincing evidence for extreme thinning ceous–early Cenozoic (Wells et al., 1998). Nevada Bull Run and Copper Basins, which of roof rocks during the ascent and crystalliza- Regional studies of Mesozoic deformation expose thick sequences of conglomerate and tion of these plutons, which would be expected in the Sevier belt east of the ARG indicate that lacustrine sediments that record the onset of if their rise was diapiric. The plutonic rocks are shortening was partitioned in time between 145 faulting as early as ca. 43 Ma (e.g., Axelrod, also involved in these extreme strains, espe- and ca. 55 Ma along four major thrust systems 1966a, 1966b; Clark et al., 1985; McGrew et al., cially along their western sides (Todd, 1980; (e.g., Armstrong, 1963; DeCelles, 1994, 2004; 2008; Henry et al., 2011). Reconstruction of Strickland et al., 2007, 2011a, 2011b) (Figs. 6 Burtner and Nigrini, 1994; Yonkee and Weil, the Cenozoic unconformity across the broader and 7). In the Albion and Middle Mountains, 2011), and that the motion on these systems region of northern Nevada and the ARG sug- the metamorphic mineral assemblages devel- migrated eastward through time, taking place gests that mostly Pennsylvanian, Permian, and oped in the attenuated roof rocks of these plu- mostly in the Mesozoic with much less short- Triassic strata were exposed at the surface prior tons indicate intrusion and fi nal crystallization ening continuing into the Cenozoic (Wiltschko to and during the eruption of Eocene volcanic at depths close to the aluminum silicate triple and Dorr 1983; Heller et al., 1986; DeCelles, rocks (Fig. 4B). The great stratigraphic thick- point, based on the presence of staurolite + 1994, 2004; Burtner and Nigrini; 1994; Yonkee ness (~7 km) of the Pennsylvanian–Permian kyanite ± sillimanite ± occasional andalusite in and Weil, 2011; Appendix 1). Geochronologic Oquirrh Group in the region around the ARG, country rocks (Figs. 6 and 7; Holdaway, 1971; and thermochronologic studies of the deeper however, makes the reconstructed Cenozoic for an alternative interpretation of the ages of parts of the stratigraphic section exposed in the unconformity a less viable method for estimat- these metamorphic mineral assemblages, see ARG indicate that this part of the hinterland of ing the depth of erosion in this region, as com- Wells et al., 2012). Asymmetric fabrics and the Sevier thrust belt was subject to burial and pared to elsewhere in the northern Basin and lineations, defi ned (in part) by the growth of metamorphism in the Mesozoic (e.g., Hoisch Range (e.g., Gans et al., 1989; Long, 2012). elongate bundles of fi brolitic sillimanite, indi- et al., 2002, 2008; Harris et al., 2007; Wells Oligocene plutons of the ARG, collectively cate top-to-the-northwest shear during north- et al., 2012). These data are compatible with termed the Cassia plutonic complex (Strickland west-southeast stretching at amphibolite facies the fact that the estimated original thickness of et al., 2011b; Figs. 3 and 5A), are geochemi- conditions, leading us to conclude that the rise the pre-Cenozoic stratifi ed section across this cally more evolved compared to earlier Eocene and emplacement of the Oligocene Cassia region is ~9–10 km (e.g., Compton et al., 1977; magmas. Although Oligocene plutons appear plutonic complex was intimately related to Hintze, 1988) and that internal thrust faulting limited in map extent due to dissection by nor- the dominant deformational and metamorphic may have thickened this section (Fig. 1A). mal faults and burial by basin fi ll (Fig. 3), geo- event mapped in its country rocks (Strickland Cenozoic igneous rocks are exposed both logic cross sections and geochronological and et al., 2011a, 2011b) (Figs. 6 and 7). Earlier within and fl anking the ARG (Fig. 3) and were petrologic investigations have been used to infer thermochrono logic studies reported 45–37 Ma intruded or erupted during three distinct events that the plutons underlie an extensive region of 40Ar/39Ar ages from rocks in the western Raft in the Late Eocene (42–34 Ma), the Oligocene the ARG (Figs. 3, 5A, and 6) (Strickland et al., River Mountains and the northern Grouse Creek (32–25 Ma; Fig. 5A), and the Late Miocene 2011b). The oldest is the Middle Mountain plu- Moun tains (Saltzer and Hodges, 1988; Wells (14–8 Ma; Compton, 1983; Perkins et al., ton, dated as 32 Ma (Strickland et al., 2011b) et al., 2000) that were interpreted as recording

1434 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

Zircons from the igneous rocks of the ARG

Figure 5. Representative cath- Middle Mountain plutonAlmo pluton Vipoint pluton Red Butte pluton 33.6 ± 0.4 Ma odolumi nescence images of 32.7 ± 0.4 Ma 29.3 ± 0.6 Ma 29.7 ± 0.4 Ma 31.2 ± 0.4 Ma 27.2 ± 0.4 Ma 23.7 ± 0.5 Ma zircon grains from igneous 29.7 ± 0.4 Ma and sedimentary rocks of the

Albion–Raft River–Grouse 2622 Creek (ARG) metamorphic ±21 Ma core complex. Cenozoic over- 2542 2109 ± 19 Ma 2584 growths are given as 207Pb- 2454 2543 ±10 Ma ± 12 Ma ± 11 Ma corrected 206Pb/238U ages, and ± 15 Ma 2184 ±9 Ma 36.3 ± 0.1 Ma Archean core ages are reported Α 2517 as 204Pb-corrected 206Pb/207Pb ±10 Ma ages. (A) Zircon grains from 100 μm Lower Jim Sage Lower Jim Sage Upper Jim Sage four Oligocene plutons empha- B Archean (2565 Ma) Green C rhyolite 9.46±0.09 Ma rhyolite 9.33±0.1 Ma rhyolite 8.19±0.14 Ma sizing the core-rim relation- Creek complex ships observed in several zircon grains. (B) Zircon grains from the Archean Green Creek Complex, emphasizing the chaotic textures observed in several zircon grains from these rocks. (C) Zircon grains from Miocene volcanic rocks of the 100 μm 100 μm Jim Sage volcanic suite, show- 100 μm 100 μm ing the relatively monotonous and luminous (low-U content) Detrital zircons from the Salt Lake Formation textures, characteristic of Snake DESample AKR-09-3 Sample JSR-09-5 River Plain–type zircon grains. (D) Zircon grains from Mio- Group 1: Zircons typically yielding cene detrital sample AKR-09–3 concordant, low error U-Pb ages showing the range in textures observed in this sample. Note the similarities of group 2 zircon 100 μm grains to the Snake River Plain– Group 1: Zircons typically yielding Precambrian? core type zircon grains. (E) Zircon concordant, low error U-Pb ages grains from Miocene detrital sample JSR-09–5 showing the range in textures observed in this sample. Note the similarities of group 2 zircon grains to the Snake River Plain–type zir-

con grains, and group 3 zircon Group 2: Zircons typically grains to the zircon grains from yielding Miocene ages with the Oligocene plutons. high errors Group 2: Zircons typically yielding Cenozoic? rim Miocene ages with high errors Group 3: Zircons typically yielding discordant 100 μm ages possibly due to complex zoning

Figure 6 (on following page). Summary of map and cross-section relations, structures, geochronology, and petrologic data from part of the Cassia plutonic complex of the Albion and Middle Mountains (Strickland et al., 2011b). Geologic map (A) and cross-section (B) were compiled from 1:12,000–1:24,000 scale mapping by E.L. Miller and Stanford University fi eld classes. For map location, see Figure 3. U-Pb geochronology is from Strickland et al. (2011b). Isograds and high-strain deformation developed during intrusion of 32–29 Ma the Cassia plutonic complex. Temperatures and pressures were close to the aluminum-silicate triple point (sillimanite common to the west; staurolite and kyanite common to the east, and andalusite is present but rare). (C, D) Outcrop and thin-section views of kyanite-staurolite assemblages in the Precambrian schist of Stevens Springs. The assemblage is synchronous to late stage with respect to foliation development. Field of view in B is ~3.5 mm in long dimension. (E) Photomicrograph of the Precambrian schist of the Upper Narrows showing extreme fl attening foliation and disk-shaped garnets with staurolite in pressure shadows, ~10 m from contact with granite. Field of view is ~3.5 mm in long dimension. (F) Photomicrograph of garnet-sillimanite bearing schist from Middle Mountain showing growth of fi brolitic sillimanite in the foliation and defi ning down-to-the-west shear bands. Field of view is ~3.5 mm in long dimension. (G) Fibrolitic sillimanite together with kyanite from the Precambrian Elba Quartzite along the northern contact of the Almo pluton. Field of view is ~3.5 mm in long dimension.

Geosphere, December 2012 1435

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al. Feet 6000 5000 4000 3000 8000 7000 ′ A pCgg C B PCe Qal stt st Qal gnt bend ky pCe D pCgg schist of Stevens Springs Yost quartzite of schist of the Upper Narrows pCgg pCgg gnt Highly attenuated Neoproterozoic units: pCe E 4667000 m Qal Qal A Ccb F ′ A Qal sill 280000 m Figure 6. Figure And +Sill Qal ky St + Ky 31

Qol

Ky + Sill St +Gt

Stt - in isograd in - Stt

ot mapped ot n Chl + Ab Qal Qal 30 Ccb ? ? Qol ? ? ? ? ? Tc ? Chl + Ab 29 deformed Cenozoic granite Approximate eastern limit of St + Ky pCe pCgg bi Qal Pzm stt Qal pCcb St 0 1 Mile 0 1 270000 m syn to post-deformation mineral assemblages gnt

pCgg

Ky(?) + St(?) (relict) p Chl Projection: UTM zone 12 N Datum: WGS 84 Sill 32 Qol Qal pCcb 32 sill pCgg Metamorphism and deformation Neoproterozoic mineral elongation/stretching lineations Older deformed and intruded fault Cassia plutonic complex Quartzite of Clarks Basin(?) and Pz marble (?) metasedimentary rocks PCe, Elba Quartzite Precambrian Green Creek gneiss Normal fault Pzm U-Pb zircon age zircon U-Pb pCe G Middle Mountain Qal pCgg A synchronous with Cassia Plutonic Complex Feet A 7000 6000 5000 4000 3000 8000

1436 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

initial cooling of footwall rocks during Eocene piric rise of the composite Cassia plutonic com- ward-younging ages were interpreted as related motion along the Middle Mountain shear zone plex and its gneissic carapace, as indicated by to migration of a rolling hinge detachment fault (Saltzer and Hodges, 1988; Wells et al., 2000; the extreme vertical attenuation of its roof and using the model of Buck (1988). Apatite and zir- Hoisch et al., 2008). wall rocks. The diapiric rise and emplacement con fi ssion track ages that range from 15.1 ± 2.4 In the Grouse Creek Mountains, the intrusion of the granite-cored gneiss domes occurred dur- to 12.1 ± 3.4 Ma (2σ; weighted average 13.4 ± of the 25 Ma Red Butte plutons was accom- ing boundary conditions that were extensional, 1.0 Ma) in the Grouse Creek and Albion Moun- panied by amphibolite facies metamorphism thus allowing strain to focus along the top of the tains are also interpreted to record the time of and extreme attenuation of section in response plutonic complex and along normal sense shear rapid exhumation of the western side of the core to west-northwest–east-southeast to east-west zones recorded by the top-to-the west indica- complex crystalline rocks to near surface condi- stretching (Fig. 7; Compton et al., 1977; Todd, tors in the strongly foliated and lineated (west- tions ca. 13.4 Ma (Egger et al., 2003). 1980; Egger et al., 2003). This west-north- northwest–east-southeast stretching) country west–east-southeast fabric is superimposed on rocks. Although strains are very high at deeper METHODS an earlier north-south–trending lineation and structural levels, elevated temperatures fostered fl attening fabric (Compton et al., 1977; Todd, amphibolite facies fabrics rather than mylonitic Geologic Mapping of Synextensional 1980) that has not been directly dated, but is fabrics with grain-size reduction (Figs. 6 and 7). Basin Sediments interpreted as Cretaceous in age by correlation In contrast, both the eastern Raft River Moun- to a dated north-south fabric developed in Ordo- tains and the western fl ank of Middle Mountain Cenozoic sedimentary and volcanic vician rocks at higher structural levels (Wells (Figs. 3 and 6) expose high-strain quartzites with se quences fl ank the ARG metamorphic core et al., 2008). lower temperature (greenschist facies) mylonitic complex on its northern, eastern, and western Field and thin section relations suggest that fabrics formed as a consequence of vertical fl at- sides (Fig. 3). This study focuses on the evolu- kyanite, sillimanite, and andalusite grew dur- tening and approximately northwest-southeast to tion of the Raft River Basin developed along the ing and shortly after the second deformation, east-west stretching and shear (Compton et al., eastern side of the Albion Mountains and north- depicted by west-northwest–east-southeast– to 1977; Wells et al., 2000; Wells, 2001; Strick- ern fl ank of the Raft River Mountains (Figs. 3, east-west–trending lineations (Figs. 7A, 7B, land et al., 2011a, 2011b). The 40Ar/39Ar ages 8, and 9). Although parts of the Raft River Basin 7D, 7E). Stretching and attenuation of section of muscovite, coupled with quartz microstruc- section were previously studied and the depos- accompanied the development of the Ingham tures indicative of greenschist facies conditions its were identifi ed as part of the Salt Lake For- Pass detachment fault under conditions where (~350–490 °C; Gottardi et al., 2011), led Wells mation (Compton, 1972, 1975; Williams et al., staurolite and kyanite were stable (Fig. 7F). The et al. (2000) to interpret that most of the exhuma- 1974, 1982; Smith, 1982; Covington, 1983; relations and mineral assemblages thus suggest tion of the Raft River Mountains occurred along Pierce et al., 1983; Wells, 2009), the exact age that the Oligocene Red Butte pluton crystallized the east-dipping Raft River detachment in the range of the strata and their relationship to the at depths close to the aluminum-silicate triple Middle to Late Miocene (15–7 Ma) (Wells et al., uplift history of the footwall rocks of the ARG point, similar to the conditions inferred in the 2000). This interpretation is consistent with fi s- were not clear before this study. Geologic map- Albion and Middle Mountains region (Figs. 6 sion track thermochronology from the Raft River ping of the sedimentary and volcanic sequences and 7; Holdaway, 1971). The 40Ar/39Ar thermo- Mountains indicating rapid cooling and inferred on the north side of the Raft River Mountains chronology of muscovite and biotite from coun- slip on the detachment between 13.5 ± 2.2 and was combined with existing map data (Comp- try rocks to the Red Butte pluton indicate that the 7.4 ± 2.0 Ma (2σ) (Wells et al., 2000). The east- ton, 1972, 1975; Williams et al., 1974, 1982; region slowly cooled below ~350 °C (biotite clo- sure temperature) by ca. 21 Ma (Sheely, 2002), compatible with the inferred ~10–15 km depths of the emplacement of the pluton. The northwest- Figure 7 (on following page). Map (A) and cross-section relations (B), structures, geochronol- southeast–stretching amphibolite facies fabrics ogy, and petrologic observations from the Grouse Creek part of the metamorphic core of the associated with the Ingham Pass detachment Albion–Raft River–Grouse Creek (ARG) metamorphic core complex and Cassia plutonic and the detachment fault are cut and displaced complex (Strickland et al., 2011b). Data were collected and compiled by E.L. Miller based by large offset Miocene normal faults along the on 1:12,000–1:24,000 scale geologic mapping by Miller, J. Lee, P. Gans, and Stanford Uni- western and eastern margins of the range (Figs. versity fi eld classes. The information shown supports the conclusion that high-strain defor- 3 and 7; Compton, 1983; Martinez, 2000; Egger mation (gently dipping foliation and west-northwest to east-west lineations) at amphibolite et al., 2003). facies conditions and the development of the Ingham Pass detachment took place during In summary, data from the various parts of the the intrusion of the 25 Ma Red Butte pluton of the Cassia plutonic complex. Temperature- Cassia plutonic complex and its wall rocks sug- pressure conditions were close to the aluminum-silicate triple point. (C) Kyanite wrapped gest that the lower crust beneath the ARG meta- by fi brolitic sillimanite. View is ~3.5 mm across in the wide dimension. (D) Kyanite + stauro- morphic core complex was at suffi ciently high lite + biotite + muscovite. View is ~3.5 mm across in the wide dimension. (E) Kyanite + temperatures to undergo partial melting across a staurolite + andalusite. View is ~3.5 mm across in the wide dimension. (F) Outcrop photo of protracted time interval spanning at least 7 m.y., kyanite. Textures indicate growth of minerals is largely late stage and/or static with respect from ca. 32 Ma to 25 Ma. Most likely the inter- to strain. (G) Extreme attenuation and highly foliated nature of Precambrian basement val of crustal melting spanned a broader range gneisses. (H) Photomicrograph of the attenuated schist of Stevens Springs beneath the of time (~17 m.y.), from 42 to 25 Ma, consid- Ingham Pass detachment showing growth of staurolite and kyanite synchronous to late with ering the ages of intrusion of the older Eocene respect to the development of foliation. View is ~3.5 mm across in the wide dimension. Red magmas (Egger et al., 2003; Strickland et al., stars highlight map and cross-section relations between the older Ingham Pass detachment 2011b). During this time span, mobilization of and the younger Miocene Grouse Creek fault and the eastern range-bounding fault. For the lower and middle crust resulted in the dia- map location, see Figure 3.

Geosphere, December 2012 1437

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al. F G 8000 7000 6000 5000 ′ A Qol - PCog Qal st st st

e t i t a m g e p

PCog

Trb

n a H

- d

pCe n u

b Pz

a 1 N A - 1 - pCss Ccb

Qal 4620000 m 4615000 m - pCe miles kilometers ′ A 0

Stt + Ky And St + Ky Sill 0 og - T Pz Gnt (relict) + St + Ky (new) Mu + Bi Chl p PCog St + Ky Ingham Pass Fault

? pCe ? - Ccb p - pCe Elba Quartzite pCss schist of Stevens Springs pCcb quartzite of Clarks Basin Figure 7. Figure - pCss 270000 m Trb Pz

T Trb - o T p

Ingham Pass Fault

Chloritoid + wt mica ± minor bi trem

o o og Sill T Qol p Trb

Pz o o Tfg T Projection: UTM, zone 12 N Datum: WGS 84 - o fault T p

Paleozoic rocks Tertiary Red Butte granite

Precambrian metasedimentary rocks sense of shear (thin section) Precambrian orthogneiss with older meta-sedimentary rocks o B Qol L2 lineations Pz Tfg normal fault Fault A Ingham Pass Pz Trb PC PCog A Grouse Cr. Grouse Cr. 8000 5000 7000 6000 Feet C E D st st st st

1438 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex , and ′ ssion F C , B–B ′ 4670000 m 4650000 m Mts. tite; Z = zircon ﬁ tite; Z = zircon 10Km D Credit for Black Pine ′ B AB geologic mapping E ′ C 30 32 320000 m d Fig. 9) and cross-sections A–A d Fig. 9) and cross-sections PER-SS Valley Raft River Area of figure 9 ′ A AKJS-09-11B 300000 m Raft River Mts. ). Geologic mapping of areas outlined in boxes: in A—after Compton (1975), B—after Compton (1972), C— Compton (1975), B—after A—after outlined in boxes: ). Geologic mapping of areas ′ AKR-09-2 ). Generalized geologic map of the Raft River Basin showing the location of sample locations analyzed in this study. Basin showing the location of sample locations analyzed in this study. ). Generalized geologic map of the Raft River AKJS-09-1 Mts. , and C–C ′ Jim Sage C AKR-09-1A , B–B ′ AKR-09-3A JSR-09-5

JSR-09-6 Albion Fault Albion data (M = muscovite; B bio et al. (2000) and indicates the locations of samples existing thermochronologic Wells is from ′ ssion track). ssion Albion Mts. A 280000 m on this and following page; key on following page on following page; key on this and following B . Cross-section C–C . Cross-section ′ C–C track; A = apatite ﬁ A track; Also shown are locations of cross sections (A–A locations of cross Also shown are Figure 8 ( Figure after Smith (1982), D—after Williams et al. (1974), E—after Miller et al. (2008), F—after Wells (2009). Legend for Figure 8 (an Figure (2009). Legend for Wells et al. (2008), F—after Miller et al. (1974), E—after Williams Smith (1982), D—after after

Geosphere, December 2012 1439

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al. ′ A ? Ts ′ B Mmc Strevell Borehole Cenozoic Sediments Oquirrh Group Ordovician metasedimentary rocks Proterozoic metasedimentary rocks (All units in normal sequence) Archean basement Ts Tv Tv Prz Elba Quartzite Anticline Accommodation fault Overturned anticline Overturned syncline Syncline Normal faults (ball on upper plate) High angle fault Raft River-Albion Detachment Older than Miocene detachment faults Road Highway Foliation Bedding boreholes Wells, Samples Lineation Ts Tg A

2 0 -2 Km Oe Archean ′ C B=13.9 ) and Key for Figures 8 and 9. Figures ) and Key for

M=15.0; Z=9.4 Cb M=14.9 continued Tonalite Pennsylvanian-Permian Oquirrh Group Mississippian phyllite, marble and quartzite Fish Haven Dolomite Eureka Quartzite Limestone and dolomite (Pogonip Group) Schist of Mahogany Peaks Quartzite of Clarks Basin Schist of Stevens Spring Yost Quartzite of Schist of Upper Narrows Elba Quartzite Augen orthogneiss Schist and metabasalt

A=7.4 Mp M=16.9

Figure 8 ( Figure

Ordovician Proterozoic Archean M=21.9 B=15.9 A=7.6 Op M=22.5 B=20.2 Z=10.8 A=8.1 PPo Archean

Elba qtzite Ts Tv M=45.2 B=33.7 A=8.6 Almo pluton

Proterozoic unconformity Shear zone boundary

volcanic suite volcanic Jim Sage Sage Jim Fault breccia and lake sediments (unit 7) Tuff Rhyolite lava flow ignimbrite Welded dome Volcanic Basalt of N. Cotterel (unit 6) Upper lava flow (unit 6) (unit 5) Middle tuff Lower lava flow (unit 4) vents Volcanic (unit 3) Lacustrine tuff Sandstone (unit 2) Conglomerate and fanglomerate (unit 1) Sedimentary rocks (undiff.) Diabase (Unkown age) Almo granite (32 Ma) Cenozoic A=10.8 B=45.4 M=47.4

B C

Miocene Salt Lake Formation Lake Salt Miocene 2 0

2 Km 0 Km –2

1440 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

22 5

30 12 lt Lake For-

25 22 10

16 24

38 10 mapping

30 5 AB

0 Credit for geologic

80 5

#8 22

00 25

50 50

44 4

on to become the northern part of what

18 0

750

25 37 23

2000 47 290000 m

40 13

20 32 19

0 41

30 250

11 18 25

0 5 7

1 30

#6 #7

28 40

14 0 0

28 20

55 60

40 7

37 2 65

50 200 0

14 25 27 15 1750

18 45

10 21

40 45 7

6 50

35 32 12 #5 34

2 40

2000 3 1750 50

60 35 2 15 1 40

5 36 12

1 40 50

16 45 45

23 16 43 10

#4 30

35 10

5 42 290000 m

25 40

3 0 #3 1

20 #2 13

15 14

14 35

0 2

15 20

32 Fault block #1

). Detailed map of the southwest part of the Raft River Basin showing the location of faults that cut and rotate the Miocene Sa Basin showing the location of faults that cut and rotate ). Detailed map of the southwest part Raft River

19 36

u A a l F

n b

o i

38 1750

2 60

32 28 34 36

0 28 2 280000 m 27

28 45

33 16 1750 8 20

35 on previous page key

35 4

2000 43

40 25

38 2000 5

35 1 60 17 5 40

4 17 2000 28 46 43 0

3 22

8 30

20 40 22

32 15 4660000 m 4650000 m Figure 9 ( Figure and continuati curvature Albion fault system and its inferred basin-bounding Also shown is the location of inferred mation. has been mapped as the Raft River detachment. The legend and geologic mapping citations are as in Figure 8. as in Figure The legend and geologic mapping citations are detachment. has been mapped as the Raft River

Geosphere, December 2012 1441

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

Smith, 1982; Covington, 1983; Pierce et al., to calculate the maximum depositional age of locally >1000 m thick and not 200–500 m, as 1983; Wells, 2009). Borehole, well log, and geo- the enclosing sediments (Fig. 10). fi rst described by Williams et al. (1982) (Figs. physical (seismic refl ection, gravity, and mag- The corrected 206Pb/238U (for zircon grains 10A, 10E; Appendix 4). netic) data initially collected for the Raft River younger than 1000 Ma) and 206Pb/207Pb ages (for The sedimentary rocks of the Salt Lake geothermal project during the early 1970s zircon grains older than 1000 Ma) were used Formation are cut by several normal faults, through mid-1970s (Mabey and Wilson, 1973; to construct relative probability diagrams and which displace and rotate the section (Figs. 8 Williams et al., 1974, 1975, 1982; Covington, cumulative probability diagrams (Fig. 11), using and 9). Average tilts of strata are ~30° to the 1977a, 1977b, 1977c, 1978, 1983; Oriel et al., Isoplot (Ludwig, 2003). The relative age prob- west with dips as steep as 50° and as shallow 1978, 1979a, 1979b) were added and these data ability diagrams show each age and its uncer- as 15°. The fault blocks (blocks 4–6) with the were used to produce the maps and cross section tainty as a normal distribution and sum all ages largest amount of rotation of strata (~48°; red shown in Figures 8 and 9, as well as the strati- from a sample into a single curve, where the symbols in Fig. 10C) are responsible for expos- graphic columns displayed in Figure 10. area under the curve equals unity. Cumulative ing the basal unconformity and the deepest probability plots normalized each curve accord- part of the sedimentary section, in the region Geochronology ing to the number of constituent analyses such north of the Raft River Mountains (Fig. 9). In that each curve contains the same area (Gehrels map view, the traces of the normal faults trend Single grain U-Pb ages were determined by et al., 2008). approximately north-south and are truncated to LA-ICP-MS (University of Arizona Laserchron The depositional age for each of the fi ve the north by an accommodation structure south facility) on detrital zircons that were separated Miocene samples was determined using the of the Jim Sage Mountains (the Narrows struc- from fi ve samples of Miocene sedimentary weighted average of the youngest detrital zir- ture of Covington, 1983). To the south, the same strata and from two samples of sandy limestone con grains from each of the samples (Ludwig, faults die out in terms of their displacement and from the underlying Pennsylvanian–Permian 2003). These data were plotted on weighted locally displace minimally (<500 m) the system Oquirrh Group. Three samples of Miocene vol- average diagrams and are presented in Figure of faults that bounds the Raft River Mountains canic rocks and one tuff from the base of the 10. Miocene-age zircon grains were excluded along their northern fl ank and separates meta- Miocene sedimentary section were selected from the suite of zircon used to construct cumu- morphic rocks of the footwall from late Paleo- for zircon U-Pb SHRIMP-RG (sensitive high- lative and relative probability diagrams, so as to zoic and Cenozoic strata (Figs. 8 and 9). The resolution ion microprobe, reverse geometry) best compare the older zircon populations in the tilted fault blocks expose the entire stratigraphy geochronology, performed at the Stanford- samples. A matrix of P-values was calculated, of the Cenozoic section (Figs. 9 and 10), but the U.S. Geological Survey facility using the using the K-S (Kolmogorov-Smirnov) statistic inferred maximum stratigraphic thickness of the methods described in Strickland et al. (2011b) (Gehrels et al., 2008), in order to better com- Salt Lake Formation (~4.5 km) is a composite, (Tables 1–3). One sample of a reworked tuff pare the detrital zircon populations of the six (of put together from partial sections measured in was analyzed using both the LA-ICP-MS and seven) samples that contain zircon grains older individual fault blocks. SHRIMP-RG techniques to obtain a more pre- than Miocene (Appendix 3; results shown in The Salt Lake Formation can be divided into cise depositional age. Fig. 11D). 7 units; units 1–6 are the focus of this study Zircon was separated by traditional crushing The Miocene detrital zircon suites were and are described in greater detail in Appendix and grinding methods, followed by standard examined with cathodoluminescence (CL) 4. Units 1–3 are almost continuously exposed separation methods that utilize the hydrau- imaging after completion of the U-Pb analyses, along the northern fl ank of the Raft River Moun- lic, density, and magnetic properties of zircon in order to identify in more detail the textural tains, where they were deposited unconform- (Gemini table, heavy liquids, and a Frantz mag- characteristics of the detrital zircon grains that ably on strata of the Pennsylvanian–Permian netic separator). For detrital zircon geochro- were dated (Figs. 5D, 5E). Oquirrh Group, and attain a maximum thickness nology, seven samples (fi ve Miocene and two of ~2.3 km (Figs. 9 and 10). Unit 1 is mostly Pennsylvanian–Permian) were processed fol- RESULTS composed of breccias, fanglomerates, and lowing the methods and analytical procedures pebble conglomerates deposited on top of the of Gehrels et al. (2006, 2008) (Appendix 2). Stratigraphy and Age of the Raft River Pennsylvanian–Permian Oquirrh Group. Clast The LA-ICP-MS analytical data are reported in Basin Deposits counts from the rocks of unit 1 indicate that Table 1. Uncertainties shown are at the 1σ level this unit records an unroofi ng sequence, where and include only measurement errors. Analy- The Salt Lake Formation, deposited in the Raft the oldest rock clasts become progressively ses that were >20% discordant (by comparison River Basin, is best exposed north of the more abundant upsection (Fig. 10D; Appendix of the 206Pb/238U and 206Pb/207Pb ages) or >5% Raft River Mountains, east and south of the Jim 4). Metamorphic (schist) clasts, presumably reversely discordant were excluded from further Sage Mountains, east of the Cotterel Mountains, from the deeper parts of the metamorphic core analyses. Many detrital zircon grains from the and locally west of the Black Pine Mountains complex, become abundant only in the pebble Miocene sediments have large analytical errors (Figs. 8 and 9). Parts of the Salt Lake Forma- conglomerates of unit 2. Granitic clasts from in terms of their 206Pb/207Pb ages, both because tion were described by Williams et al. (1982), either the Archean orthogneiss or the Oligocene of their young age and low 207Pb counts, thus who noted three tuffaceous members (lower, Almo pluton were not observed in either unit 1 yielding either high 207Pb/235U or 206Pb/207Pb middle, and upper) and the rhyolite and basalt or 2 (Appendix 4). Unit 3 is composed of a thick errors, and high discordance estimates, and fl ows of the Jim Sage volcanic member (Fig. sequence (~1000 m) of lacustrine fi ne-grained were also excluded from further analyses. Sev- 10E). Here we present evidence that there are ash-fall tuffs and marls. eral detrital zircon grains from the Miocene two more units (identifi ed as unit 1 and unit 2) Units 4–6 are composed of ~1 km of vol- sedi ments yielded Miocene (younger than below the lower tuffaceous member of Williams canic rocks that are best exposed in the Jim 15 Ma) 206Pb/238U ages with acceptable errors et al. (1982), and we describe the full thickness Sage (units 4 and 5) and Cotterel Mountains (±3 m.y.). These young zircon grains were used of their lower member (unit 3 of this study), (unit 6) (Figs. 3, 8, and 10; Appendix 4). The

1442 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

Unit 7 Mean = 8.19 ± 0.14 (1.7%) 15.0 A 14.0 Lacustrine tuff with 95% conf. 14 data points 13.0 lava clasts MSWD = 1.4 12.0 error symbols are 2σ Basalt flows 11.0 10.0 9.0

3.0 km 8.0 Age (Ma) Unit 6 7.0 Rhyolitic lavas and Rhyolite lava (n=14) 6.0 ignimbrite 5.0 Capped by basalt flows 15.0 Mean = 9.33 ± 0.1 (1.2%) 14.0 95% conf. 16 data points 13.0 Unit 5 MSWD = 0.86 12.0 error symbols are 2σ Tuff with lava clasts 11.0 10.0 2.5 km 9.0 Unit 4 8.0 Age (Ma) Rhyolitic lava flows 7.0 6.0 and ignimbrite Rhyolite lava (n=16) 5.0 15.0 Mean = 9.46 ± 0.09 (0.9%) 14.0 95% conf. 22 data points 13.0 MSWD = 1.5 12.0 error symbols are 2σ 11.0 10.0 2.0 km 9.0

Figure 10 (on this and following 8.0 Age (Ma) page). (A) Detailed stratigra- 7.0 phy of the Miocene Salt Lake Rhyolite lava (n=23) 6.0 5.0 Formation exposed north of the 30 Raft River Mountains. Aster- Mean = 9.7 ± 0.7 (7.4%) 2σ MSWD = 3.9, 1 of 16 rej. 25 isks indicate the stratigraphic error symbols are 1σ position of dated samples. The 20 leaf symbol shows the position 15 1.5 km of plant fossils (Compton, 1972; Unit 3

10 Age (Ma) this study). The seven units Intercalated lacustrine described are based on this tuff, sandstone, marls 5 and mudstones Youngest ages (n=15) study. MSWD—mean square 0 30 of weighted deviates; SHRIMP- Mean = 10.5 ± 0.4 (4.0%) 2σ RG—sensitive high-resolution MSWD = 1.4, 3 of 17 rej. 25 error symbols are 1σ ion microprobe, reverse geom- 20 etry; conf.—conﬁ dence. 1.0 km JSR-09-6 15

10 Age (Ma) Unit 2 Intercalated coarse, 5 Youngest ages (n=14) fluvial sandstone and 0 pebble conglomerate 30 metamorphic Mean = 13.3 ± 0.2 (1.4%) 2σ MSWD = 1.9, 0 of 9 rej. 25 clasts error symbols are 1σ 20

0.5 km 15 Unit 1

10 Age (Ma) Breccias, fanglomerates and 5 SHRIMP-RG conglomerates Youngest ages (n=9) 0 Zircon U-Pb 30 Mean = 13.45 ± 0.28 (2.1%) 2σ analysis MSWD = 0.17, 0 of 16 rej. 25 LA-ICP-MS Rapid motion on Albion bounding faultRapid motion on Filling of topographic depression (lake deposits) Faulting and rotation of sequence error symbols are 1σ 20 Zircon U-Pb 0.0 km analysis Unconformity 15 Oquirrh Group Zircon U-Pb 10 Age (Ma) Sandy limestone SHRIMP-RG analysis and siltstone analyses 5 rejected by Tuff (n=16) 0 Isoplot

Geosphere, December 2012 1443

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

B C N Unit 7 (<8.2 Ma) Lacustrine sequecne

Unit 6 (8.2 Ma) Upper rhyolite and basalt Unit 5 (9.33–8.2 Ma) Tuffs and breccias Unit 4 (9.46–9.33 Ma) Lower rhyolite

Unit 3 (9.7–9.46 Ma) Lacustrine sequence S. Jim Sage N. Raft River Mnts Unit 2 (10.5–9.7 Ma) Mean pole to plane Fluvial sequence n = 20; Mean bedding n = 49; Mean bedding plane: N12W, 31.6 E plane: N15E, 47.7 W

Unit 1 (13.5–10.5 Ma) *Bedding readings from all stratigraphic levels Alluvial Fan sequence exposed in each of the two regions. Permian Oquirrh **Contour intervals (shaded) at 25 and 50% per Group 1% of area

Ordovician D Younger and older alluvium

Basalt Flows Group

Upsection Snake River Raft Formation (0–100 m)

Upper tuffaceous Pliocene member (0–1200 m)

Proterozoic Permian (our unit 7)

*Modal composition based on ~300 point counts Tuff of Cedar Knoll of clasts from polished slabs. **Symbols correspond to symbols on stratigraphic column (Fig. 10A). Basalt of N. Cotterel (0–30 m)

Figure 10 (continued). (B) Generalized facies relations in Upper rhyolite the Salt Lake Formation. (C) Equal area, lower hemi- flows (0–500 m)

sphere projection plot of poles to bedding. Blue sym- (our unit 6)

bols and contour intervals are for measurements from Salt Lake Formation Middle unit (0–100 m)

a continuous section exposed south of the Jim Sage MIOCENE(our unit 5) PLEISTOCENE Mountains. Red symbols and contour intervals are for attitudes measured from a continuous section exposed Lower rhyolite north of the Raft River Mountains. (D) Ternary diagram flows (0–500 m) showing the modal composition of clasts in the conglom- (our unit 4) erates and breccias of unit 1 (identiﬁ ed visually based on lithology). The symbols are color coded according to their locations on the stratigraphic column. The modal Lower tuffaceous composition of the clasts shows an unrooﬁ ng sequence member (200–500 m) with stratigraphically older clasts found at the higher (our top of unit 3) levels of unit 1. (E) Stratigraphy of the Salt Lake forma- E tion (as reported in Williams et al., 1982).

1444 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

volcanic rocks in the Jim Sage Mountains were Sample AKR-09–1A is from the matrix-sup-

deposited locally above an angular un con- ported pebble conglomerate deposited at the top 8 2 2 4 7 4 . . . . . U 0 0 0 0 0 238

formity of ~5°–15° (depending on location) of the fanglomerates of unit 1 (Fig. 10A; Table 2). A ± ± ± ± ± / N 3 5 5 7 5 . . . . Pb/

developed across older Miocene sedimentary Of the 100 detrital zircon grains analyzed using 4 3 0 . 9 0 with error 206 1 3 1 1 1

rocks of units 1–3 (Williams et al., 1974, 1982; LA-ICP-MS, 55 were concordant and older than youngest age Weighted mean Weighted Pierce et al., 1983; Covington, 1983; this study) 20 Ma, and were used to plot relative and cumu- (depositional age) and are gently tilted by normal faults, forming lative probability curves (Figs. 11B, 11C). Zir- an antiformal structure. Units 4–6 are displaced con grains range in age from Paleoproterozoic 6 7 9 9 7 0 0 0 2 7 9 9 8 7 by ~2–3 km along the Albion fault and are also through Mesoproterozoic (2000–1000 Ma), with 7 (m) Elev. 1 1 1 1 cut by steep (50°–60°), small-offset normal multiple peaks, notably ca. 1800 Ma, 1500 Ma, 1 faults. The stratigraphic section of unit 4 was and 1000 Ma (Fig. 11). The sample has Archean 9 4 zircons (ca. 3300–2600 Ma) and a small num- 2

measured in the southeastern part of the Jim 8 5 3 9 5 7 5 6 0 0 1 2 1 3 8 . . . . . Sage Mountains, whereas units 5 and 6 were ber of zircon grains that are early Paleozoic (ca. . 0 0 3 9 4 1 1 3 3 3 2 measured in the southern Cotterel Mountains 550–450 Ma). One zircon crystal is Cretaceous 3 3 3 3 3 3 3 1 1 1 1 1 1 1 1 1 1 1 (Appendix 4). Unit 7 is poorly exposed along in age (ca. 120 Ma) and one discordant zircon 1 Coordinates

the southern fl ank of the Cotterel Mountains (not included in the diagram) has an Eocene age (Deg. Dec. Min.) (upper tuffaceous member of Williams et al., (ca. 40 Ma). Nine detrital zircon grains, with low 4 1 0 2 7 0 9 0 5 7 9 6 7 3 8 6 8 3 . . . . . 1982) and along the western fl ank of the Black error Miocene ages, yield a weighted average age . 4 8 7 8 4 7 NW 0 1 5 5 5 Pine Mountains (previously mapped as undif- of 13.25 ± 0.3 Ma (Fig. 10A), interpreted to be 5 2 1 1 1 2 1 4 4 4 4 4 ferentiated Cenozoic sediments by Smith, close to the depositional age of unit 1. Approxi- 4 1982; Wells, 2009). The maximum thickness mately 35 detrital zircon analyses resulted in of unit 7 is ~1.2 km based on drill core data ages with either high 206Pb/238U or high 207Pb/235U x i r t e ow 42 05.097 29.690 113 1846 9.33 ± 0.10 ow 42 21.606 27.364 113 2159 8.19 ± 0.19 ow 42 12.174 25.464 113 1591 9.46 ± 0.09 t fl fl fl from the eastern part of the Jim Sage Mountains errors, mostly because these zircon grains are a a r a a a m e v v v e

(Williams et al., 1982; Pierce et al., 1983; Cov- young (Miocene). y a a a t m s l l l l e i o o s l n e e e k t t ington, 1983; Figs. 8 and 10E), and the younger Sample JSR-09–6 is a coarse-grained mus- t g o i i i r l l l h t t n a i s o o o o y y y strata of unit 7 have been interpreted to be Plio- covite-rich sandstone, deposited near the top of d w h c n h h h n c r r r i o e e a i r l t s - s y y cene in age (Williams et al., 1982). Unit 7 is unit 2 (Fig. 10A; Table 2). Of the 100 detrital y e f b p c o s s s f i i n b e r k s s s u h r o t e c n t a a a t i

cut by normal faults and dips gently west ~10° zircon grains analyzed, 67 are concordant and i l l l a l l s r p l s t g g g e a h e d s d f c D h h h - n except where it is exposed on the western ﬂ ank older than Miocene, and used to plot relative u e i m t r c c c i c h a i i i l r r r r – s a o l - - - a y c l l l

of the Black Pine Mountains, where it dips and cumulative probability curves (Fig. 11). The a i t p c l s a a a i i h t t t p h t u s i s s s c u m l i ~30° to the east (Fig. 8). The Miocene–Pliocene zircon population in this sample is very similar o y y y s r d r r r e - - e e e c c c c x s s d r i r r r - r Salt Lake Formation is overlain by the early to AKR-09–1A, with Mesoproterozoic and a f t f a a f a f % % % a o o u h u 0 5 Pleistocene Raft Formation, middle Pleistocene Paleoproterozoic zircon populations (Figs. 11B, 5 B S C 2 1 T 2 M C basalts of the Snake River group, and by uncon- 11C). It has Archean zircon (ca. 2500–3300 Ma) solidated late Pleistocene alluvium (Fig. 10E; and several zircon grains that are early Paleo-

Williams et al., 1982). zoic (500–450 Ma). Only two detrital zircon e n o grains yielded low error, concordant Miocene t s d

Detrital Zircon Geochronology ages from this sample and were combined with n a s t i y

Miocene zircon grains from sample AKR-09–3, n t l i U Detrital zircon geochronology of ﬁ ve Mio- which was collected from the same unit, to s n a i 6 1 2 2 4 3 4 cene samples is discussed from the oldest to calculate an approximate depositional age for 1 m t t t t t t t t i i i i i i i i r n n n n n n n n the youngest sample. Sample AKR-09–2, from unit 2 of 10.5 ± 0.4 Ma. Three detrital zircon e U P U U U U U U U the stratigraphically lowest tuff, was collected grains from this sample yield discordant ages ~300 m above the basal unconformity of the and 24 yielded analyses have high 206Pb/238U or e e e e e e e 207 235 e n n n n n n n n section (Fig. 10A; Tables 2 and 3), and has abun- high Pb/ U errors, mostly because of their n a i e e e e e e e e e c c c c c c c c m g r o o o o o o o dant reworked glass shards. Zircon crystals from young (Miocene) age. o i i i i i i i i A e TABLE 1. INFORMATION ABOUT SAMPLES USED FOR DETRITAL ZIRCON AND SHRIMP-RG GEOCHRONOLOGY ZIRCON SAMPLES USED FOR DETRITAL ABOUT 1. INFORMATION TABLE P M M M M M M M this sample were dated both by LA-ICP-MS Sample AKRR-09–3 is a medium-grained M (nine zircon grains) and with the SHRIMP-RG quartz and feldspar-rich sandstone, deposited (seven zircon grains). A large number (~30) of near the top of unit 2 (Fig. 10; Table 2). A popu- n n n n n e o o o o o p c c c c zircon grains analyzed by LA-ICP-MS resulted lation of 54 detrital zircon analyses yielded con- c r r r r r y i i i i i t z z z z 206 238 z s s s s e l l l l l

in Miocene Pb/ U ages (ca. 18–13 Ma), but cordant ages, with acceptable errors and ages l u u u u a a a a a p t t t t t o o o o i i i i i r r r r r e e e e m t t t t had high errors (due to their young age) or high older than 20 Ma, and were used to plot relative t n n n n a e e e e e g g g g S D I I I D D I D common lead (204Pb), and so were excluded and cumulative probability curves (Fig. 11). The D from the calculation of depositional age. The zircon population age range is similar to that of 16 concordant zircon analyses obtained by both the previous samples, but the abundances of r

geochronology techniques represent a unimodal different ages differ in a signiﬁ cant way (Fig. e 206 238 b 1 m B 2 population with a weighted average Pb/ U 11). This sample lacks appreciable amounts A 1 1 u 0 1 3 1 – – 6 5 n – – – – Datum for coordinates is NAD83. N/A—not determined. 9 9 – – S 9 9 9 age of 13.45 ± 0.28 Ma (with a low MSWD of Phanerozoic zircon but has moderate popu- 9 e 0 0 9 9 l - - 0 0 0 S 0 0 0 - - p - - - - - S S R R J C J R [mean square of weighted deviates] of 0.17), lations ranging in age from Paleoproterozoic R m R R Note: K a K K E K K K S S P DC-1 Detrital zircon Permian Oquirrh Formation Blue-gray sandstone with calcite cement 41 49.903 133 41.258 N/A A S A A J A J A interpreted as a depositional age (Fig. 10A). through Mesoproterozoic (Figs. 11B, 11C). A

Geosphere, December 2012 1445

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al. ) continued ( (%) Comments Conc ± (Ma) (Ma) Best age ± (Ma) Pb* 207 Pb*/ 206 ) a M ( ± s e (Ma) g a t U n e 235 r a p p Pb*/ A 207 ± (Ma) U* 238 Pb*/ 206 corr. error ± (%) U 238 Pb*/ 206 s ± o (%) i t a r e U* p o t 235 o s I Pb*/ 207 ± (%) Pb* 207 TABLE 2. DATA USED TO CALCULATE U-Pb AGES OF DETRITAL ZIRCONS FROM PERMIAN AND MIOCENE ROCKS ZIRCONS FROM PERMIAN AGES OF DETRITAL U-Pb CALCULATE TO USED 2. DATA TABLE Pb*/ 206 Pb U/Th 204 Pb/ 206 U 54.41 14154.88 1.08 12.57 2.04 1.9590.13 36341.43 3.13 3.29 11.30 0.18 2.37 1.60 0.76 1053.46 23.01 2.83 1097.30 3.90 20.99 0.23 1185.33 3.56 40.39 0.91 1185.33 1343.01 40.39 43.18 88.9 1362.62 29.30 1393.50 30.71 1393.50 30.71 96.4 51.23 18515.77 2.1273.8766.54 11.75 30402.31 2.28 29412.15 3.72 2.05 8.35 5.1759.45 2.5043.96 0.76 14616.08 1.05 1.11 10746.10 4.03 1.62 5.82 13.23 9.90 13.22 0.21 4.97 1.76 1.63 3.47 3.34 0.86 0.35 1245.37 0.50 3.99 39.35 1.84 4.91 1.37 0.9985.58 0.78 1272.53 1.76 1945.96 5.26 2597.93 13843.37 29.26 82.49 2.11 29.27 0.29 0.18 1949.17 1318.68 2696.51 13.37 0.65 43.09 4.07 0.37 16.66 39.68 0.77 1623.20 1.82 1318.68 1952.57 1045.52 2771.24 39.68 9.37 39.25 94.4 13.64 1.79 18.25 1631.66 1058.53 1952.57 2771.24 13.64 14.25 34.60 18.25 2.93 99.7 93.7 1642.56 1085.44 0.17 30.24 66.94 2.29 1642.56 1085.44 0.78 30.24 66.94 1031.95 98.8 96.3 21.88 1042.06 19.07 1063.33 36.54 1063.33 36.54 97.0 71.75 23492.91 2.32 10.52 1.14 3.7160.39 2.68 25032.91 0.93 0.28 13.21 2.43 0.91 2.97 1606.03 34.55 1.87 1573.35 21.46 3.20 1529.78 0.18 21.40 1.19 1529.78 0.37 21.40 1064.50 105.0 11.68 1071.92 21.18 1087.06 59.53 1087.06 59.53 97.9 99.60 36705.45 1.87 9.90 0.81 4.05 1.33 0.29 1.05 0.79 1644.47 15.28 1643.85 10.82 1643.03 15.04 1643.03 15.04 100.1 111.21 56930.55 1.08 9.83 1.01 4.07 1.29 0.29 0.81 0.62 1643.47 11.68 1649.10 10.56 1656.27 18.78 1656.27 18.78 99.2 112.53 36961.98 1.25 9.76 0.44 4.27 1.84 0.30 1.79 0.97 1701.43 26.74118.31 1686.77 93808.96 15.15 0.65 1668.58 8.52 8.21 0.42 1668.58 8.21 102.0 5.57 1.07 0.34 0.98 0.92 1908.49 16.17 1912.22 9.17 1916.26 7.55 1916.26 7.55 99.6 (ppm) 173.45 37512.32298.91 2.56157.57 512895.47 2.78 11.62 65973.89476.61 2.00 10.04 138881.70 2.95 0.75 10.52135.98 0.42 12.36 43166.59 2.70 0.82 0.78174.42 3.66 0.43 1.45 23710.38 3.38 9.88 2.35 2.95178.38 2.32 0.23 1.76 13.40 0.66 64893.38 0.27 3.89 1.24 0.72 0.85 0.26 0.93 2.92 3.92 1321.21 11.27 0.99 0.21 1.56 14.76 1522.68 0.89 1.14 1.77 0.97 0.58 39.64 1328.50 1480.34 0.80 20.59 10.73 1562.81 1217.95 0.28128.86 2.18 2.91 23.56 1500.34 79206.20 6.46 1340.25 0.93371.13 1.97 0.17 0.82 13.78159.59 4.86 1218.43 1617.43 45219.71 14.58 1597.25 3.37 1.97 88917.79 1528.68 8.67 1340.25 13.21 5.14 0.90 3.24 0.24 7.87 14.58 1025.37 1618.28 15.42 9.42 1617.43 98.6 1219.29 0.48 4.76 18.69 8.57 1528.68 0.98 7.87 9.24 15.42 1035.85 1374.95 0.26 94.1 8.48 5.29 96.8 0.37 1645.74 58.94 14.17 1219.29 8.48 4.13 1384.35 12.21 0.84 1058.05 5.40 99.9 36.73 1645.74 2.73 12.21 18.83 0.33 3.35 1398.85 97.1 1058.05 18.83 0.70 0.28 0.83 18.65 0.34 96.9 1850.80 2.72 1398.85 1.00 18.65 3.32 11.23 0.99 1600.87 98.3 1866.76 1865.86 38.50 53.86 7.21 1659.30 1884.99 22.31 1884.55 28.67 1734.06 8.57 1906.11 1884.55 4.86 8.57 6.68 1734.06 98.2 1906.11 4.86 6.68 92.3 97.9 198.35553.99 149254.65 2.26 52567.22 3.08 10.05233.95130.81 11.97 67242.23152.51 3.66 21679.71 0.56100.73 3.56 91459.31 1.38 1.21 41024.71 9.97 3.88 13.85 2.44122.17 2.67 4.66496.08 10.37 0.39 45280.36 2.03 1.53173.00 488283.10 2.19 3.73234.01 141548.52 5.97 0.31 1.95 1.58187.94 0.28 3.71 17180.32 1.66 9.89124.16 120834.48 8.45 1.00 0.23 16.30 3.66 1.95278.43 4.45 44820.37 0.94 0.96 3.20107.19 1.73 17.45 2.27 0.48 5.81 15171.44 10.72 1604.17 0.33253.80 0.97 1.77 1.73 33918.74 0.27 0.51165.59 151781.82 5.28 27.64 2.45 1346.07 0.17 9.79 1.87 3.12 4.02 17.78 0.55 24651.39 0.53 70.56 4.84 1608.84 0.86465.89 19.06 1.15 11.42 0.81 0.24 0.91150.76 0.47 147758.25 16.36 1321.42 9.51 0.61 1.74 1.52 0.57 1532.90 3.00 2.88135.82 0.98 1.74 3.30 17.78 5.04 64150.98 44.14 1.77 991.62 1.17139.64 11.70 0.95 139139.45 1614.95 2.13 2831.35 10.61 1.70 0.29 0.57 4.10 3.70 1390.01 7.45 0.30 40552.40 39.81 1574.16 0.54 1281.65 0.81 3.81 0.61 10.51 10.68 1.56 63.03 2.89 1.44 2894.65 9.88 1.71 0.07 7.53 0.95 991.68 0.18 1.30 1614.95 4.27 26.80 1.69 0.26 0.98 3.37 1456.77 10.51 16.89 0.96 0.58 9.09 1634.26 10.98 0.58 1281.65 2.30 1675.18 2.00 1629.90 40.90 99.3 26.80 3088.29 0.29 0.43 0.61 20.81 0.54 1.64 3.26 0.07 25.23 0.75 105.0 2938.97 4.00 41.53 0.53 991.83 0.24 1638.91 3.32 1555.51 450.12 1.15 1472.93 7.21 1791.77 1.76 0.29 0.88 4.01 1.61 3044.93 12.36 0.52 5.06 1629.90 31.15 1.98 8.68 0.07 8.07 14.65 29.75 1644.96 0.86 4.85 2.40 17.04 2938.97 1.54 7.21 430.34 1555.51 16.68 0.25 0.94 1644.86 1.18 991.83 1481.34 1382.70 1.23 458.87 5.06 1930.32 29.75 94.0 31.15 0.31 3016.43 1663.69 7.32 0.26 1.32 24.62 1653.40 100.0 13.68 96.3 1.60 6.34 89.4 0.29 8.92 22.57 0.99 466.07 10.62 5.82 1378.87 2.32 435.27 8.11 1644.86 1440.70 0.32 0.97 1493.39 1687.32 502.98 1930.32 1.09 5.53 17.35 11.94 3016.43 8.92 0.93 1664.11 20.72 1477.47 5.82 13.49 1.21 10.12 8.11 1626.16 99.4 68.71 0.92 465.48 30.67 1372.92 1470.38 86.8 102.4 11.32 461.42 1493.39 15.73 1716.79 1788.59 14.94 450.12 10.12 12.54 1486.93 1664.11 22.55 18.93 11.32 1635.44 8.68 63.81 98.6 18.70 10.39 1372.92 1513.48 462.60 98.8 1794.11 89.5 22.55 1716.79 9.56 430.34 100.7 1500.43 10.39 11.13 7.32 84.42 3.42 96.9 1647.37 93.3 11.06 1513.48 1800.52 466.07 1500.43 3.42 5.53 8.03 11.06 100.7 95.2 9.63 1647.37 98.5 1800.52 8.03 9.63 98.7 99.3 658.85 432378.37 6.10285.86 108393.13 8.68 2.54 13.59 0.68161.16133.15 47590.39 0.65 4.15 2.27 73773.22307.30 2.41344.49 2.98 1.69 28733.66 9.48 158320.98 2.45 6.00 1.77100.41 0.26 1.45243.22 18.59 0.59 77458.29 11.17 3.13 0.33 2.90 66980.70 0.17 0.97 3.16 1.79122.95 4.41 1495.67 11.46 0.54 10.72 1.30 12.52 55163.35 38.77 0.90 1.81 3.23 0.48 0.95120.43 0.76 1663.74 2.80 992.09 1.49 10.37 50512.94 24.41 11.96 0.30182.20 2.35 2.32 0.47 2.82 0.66277.80 1003.77 48786.26 2.04 1882.88 3.18 1.12 164732.91 0.99 11.22 0.69 0.07 0.98 8.52132.30 0.23 9.26 0.90 1.34 12.28 1707.68 3.00 2467.62 11.27 1.52 66340.92 3.53 0.96 1882.88 0.38 47.64 0.65 1029.35 8.23 2.77 0.23 14.10 0.57 12.28 0.18 1714.85 407.43 1318.65 0.64 79.4 13.08 1.68 2498.97 10.03 0.94 2.94 0.32 26.75 0.70 1029.35 2.61 5.99 4.54 7.08 0.87 13.08 1357.44 0.27 2.78 0.63 1723.61 1.18 1356.22 1093.73 400.80 96.4 11.49 5.73 2524.53 1.25 26.21 4.97 0.74 10.89 1.15 1360.86 7.78 0.24 3.78 1.20 1127.78 1517.77 1723.61 5.51 10.02 1415.94 10.89 0.68 0.23 16.85 20.43 362.77 2524.53 0.58 0.99 0.34 99.1 1366.21 5.51 10.39 1533.77 1381.68 0.96 1193.94 40.44 0.83 97.7 1415.94 1.15 0.27 13.27 18.33 8.48 0.96 10.39 1318.63 407.43 29.31 1366.21 1895.54 0.76 93.1 11.41 1391.39 1555.88 18.33 5.99 1193.94 0.77 18.94 29.31 112.3 99.4 1349.50 1564.02 8.92 21.05 91.6 1935.21 10.59 1555.88 8.58 1406.30 10.35 21.05 1587.70 97.6 1398.74 18.38 1977.95 7.93 1406.30 12.17 18.38 1619.28 5.68 1398.74 98.2 12.17 1977.95 11.70 94.3 5.68 1619.28 95.8 11.70 96.6 DC1 (Permian sandy limestone) DC1-001 DC1-035 DC1-036 DC1-038 DC1-039 DC1-042 DC1-045 DC1-048 DC1-051 DC1-054 DC1-057 DC1-061 DC1-064 DC1-065 DC1-066 DC1-002 DC1-003 DC1-005 DC1-006 DC1-008 DC1-009 DC1-010 DC1-011 DC1-013 DC1-015 DC1-016 DC1-017 DC1-019 DC1-020 DC1-021 DC1-022 DC1-023 DC1-024 DC1-025 DC1-026 DC1-027 DC1-029 DC1-030 DC1-031 DC1-032 DC1-033 Sample number DC1-034 DC1-037 DC1-040 DC1-043 DC1-044 DC1-046 DC1-047 DC1-049 DC1-050 DC1-052 DC1-053 DC1-055 DC1-056 DC1-058 DC1-060 DC1-063

1446 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex ) continued ( (%) Comments Conc ± (Ma) (Ma) Best age ) ± (Ma) continued Pb* 207 Pb*/ 206 ) a M ( ± s e (Ma) g a t U n e 235 r a p p Pb*/ A 207 ± (Ma) U* 238 Pb*/ 206 corr. error ± (%) U 238 Pb*/ 206 s ± o (%) i t a r e U* p o t 235 o s I Pb*/ 207 ± (%) Pb* 207 Pb*/ 206 ) TABLE 2. DATA USED TO CALCULATE U-Pb AGES OF DETRITAL ZIRCONS FROM PERMIAN AND MIOCENE ROCKS ( ZIRCONS FROM PERMIAN AGES OF DETRITAL U-Pb CALCULATE TO USED 2. DATA TABLE Pb U/Th continued 204 Pb/ 206 U 83.50 71656.35 2.07 9.80 0.92 3.98 1.34 0.28 0.98 0.73 1606.20 13.94 1630.60 10.90 1662.21 16.98 1662.21 16.98 96.6 68.38 22429.79 0.9134.65 13.14 7112.4754.51 1.73 1.3090.71 9774.0586.01 58918.76 13.34 1.7897.91 1.79 46935.85 1.90 1.85 57405.93 13.5386.78 10.15 1.86 4.6598.30 1.86 22503.49 6.21 12.49 3.65 3.00 30100.32 1.00 1.76 1.97 0.18 12.21 0.62 1.67 1.73 12.36 1.32 5.03 3.39 0.71 1.06 8.30 1074.98 4.39 2.15 0.17 1.58 2.60 13.10 5.18 2.40 1.91 0.1722.47 2.44 1082.73 0.25 0.38 2.3094.18 16974.19 12.36 1015.13 3.21 0.37 1.85 1.77 2.40 0.19 0.73 57372.40 17.93 0.92 2.08 2.12 1098.38 1013.01 5.14 1435.90 1.78 0.21 0.99 1032.09 5.08 30.13 0.73 10.61 0.21 30.93 26.06 2049.24 32.58 1146.20 1.52 1021.14 1098.38 90.24 0.82 1502.18 0.93 1.35 18.65 26.06 1.21 28.30 0.65 1068.23 1244.14 20.41 2264.73 97.9 1164.33 1210.09 17.19 15.13 46.95 1038.58 93.48 14.94 16.88 3.32 1596.94 1243.93 1068.23 2465.47 60.50 1.86 93.48 1213.25 13.28 18.68 1198.25 2.02 1038.58 95.0 14.71 1596.94 10.42 60.50 0.5683.35 1243.57 32.91 18.68 2465.47 0.26 97.5 1218.90 20136.35 1198.25 89.9 10.42 1.61 20.74 32.91 1.67 0.87 1.6277.62 83.1 30.98 1243.57 0.80 95.7 2856.98 20.74 13.28 1218.90 1468.29 9278.89 37.19 100.0 30.98 2.6244.36 21.21 99.3 2823.27 2.19 14578.20 1486.91 9.14 17.74 2.31 15.74 1.65 2799.27 14.22 0.9813.25 1513.55 5.92 15.29 15315.04 5.08 22.78 3.21 2799.27 4.6941.97 15.29 0.16 1513.5552.82 102.1 22.78 29521.74 1.60 5.05 4.21 1.97 5.50 97.0 7056.6880.71 0.93 1.22 6.11 0.31 1.19 13957.87 3.98 952.57 3.13 13.30 48.73 4.09 0.16 15.24 0.97 13.69 0.47 990.79 1745.32 3.64 3.40 0.56 4.89 62.56 37.49 21.40 2.24 983.57 1765.86 1.78 0.56 1076.43 31.03 1.99 35.23 1.73 4.74 43.98 3.82 0.97 969.46 0.62 1790.22 1076.43 2.56 2857.75 38.18 43.98 0.17 109.40 1.94 17.89 88.5 0.97 0.17 2830.15 1790.22 1.15 937.57 3102.94 0.30 17.89 46.59 1.23 104.14 47.74 1024.06 97.5 0.48 10.88 3156.92 2810.54 937.57 1020.26 104.14 104.9 19.34 11.64 1039.95 19.47 24.87 1018.68 2810.54 3191.40 19.47 16.45 1073.52 101.7 7.38 1015.25 73.21 3191.40 1073.52 7.38 45.41 73.21 97.2 1015.25 95.4 45.41 100.5 110.57 62692.39 1.08 9.82 0.92 4.09 1.56 0.29 1.27 0.81 1649.97 18.42 1653.15 12.76 1657.19 17.01 1657.19 17.01 99.6 211.99 89780.23 1.23 9.84 0.78 4.04 1.84 0.29 1.67 0.91114.07 1634.14 28869.96 1.58 24.09211.92 1642.89 17.08 45768.50 3.20 14.99 3.23 13.28 1654.08 14.43 0.60 0.91 1654.08 14.43 3.48 1.95 98.8 0.07 2.58 1.29 0.37 0.19 464.15 2.42 0.94 5.79 1108.04 478.88 24.62 13.29 1097.62 17.32 550.04 1077.04 70.59 18.17 464.15 1077.04 5.79 18.17 102.9 84.4 (ppm) 107.23 69801.78 1.53 10.31 0.87 3.44 4.86 0.26 4.78 0.98 1473.76 62.97 1512.64 38.23 1567.49 16.34207.04 1567.49255.21 16.34 65699.26 125308.78 1.19 94.0 3.65168.99 9.79 10.63 81042.17 2.03 0.33 0.44 9.71 3.95 3.25 0.64 0.97 1.62 4.10 0.28 0.25 2.88 0.91 1.55 0.94 0.96 1592.99 1440.68 0.29 12.85 20.07 2.80 0.97 1623.87 1468.40 1636.76 12.54 7.84 40.54 1508.69 1664.11 1654.99 23.49 8.31 6.06 1508.69 1678.18 1664.11 8.31 6.06 11.86 95.5 95.7 1678.18 11.86 97.5 324.78 184896.24 3.31417.01474.30 52831.13401.14 8.89 0.89 97816.17 131042.43 1.99 2.80415.37 17.60 0.49 325299.91 16.89 1.77 9.33 1.63 4.93 0.96 9.80 0.26122.47 0.56 1.27 61411.02 0.71 0.20 3.89 4.46276.25 2.20 0.32187.50 185773.72 2.33 10.17 4.00 2.42425.95 1.05 110780.98 1.17 0.07 2.37457.87 0.92 0.09 56141.25 10.55 0.78185.39 337923.72 1.51 1.72 1779.44 1.48 0.30 4.11221.77 0.67 179653.02 5.07 2.12 18.19 1.19493.17 0.91 125427.38 17.81 1.01 0.28 0.56 3.41 444.66 1.46 0.97 1807.69 9.40 54228.15 534.45 0.16 9.66 2.14 1699.58 1.49 6.36 10.71 1.57 10.87 0.99 1.68 3.32 9.43 15.12 0.35 14.07 14.51 1611.98 451.23 1840.41 0.46 542.26 1723.13 0.25 21.31 0.53 1.64 0.54 8.03 3.99 2.20 9.78 0.75 8.68 8.92 1633.88 1.49 4.13 0.25 0.89 2.09 1840.41 12.24 3.93 484.89 0.52 1751.84 2.90 1446.54 575.24 8.92 1.11 1.54 1.09 0.07 19.28 0.94 1662.17 36.10 96.7 2.20 1.82 20.97 0.27134.77 4.85 1.00 1458.34 8.06 1506.61 1.38 0.29223.96 444.66 1751.84 2688.96 39602.02 0.66 3.67 534.45 20.13 2.88 0.27166.40 13.19 6.36 2.33 10.87 4.85 71105.82 0.99 48.32 1662.17 0.99 0.12259.11 423.38 2.83 1485.07 46436.71 0.91 91.7 92.9 1552.37 97.0 1.73200.57 3.67 1592.10 10.84 3.79 2754.12 74847.02 0.95 12.81 1637.31 8.02 5.65 39.76 2.48 97.0 43218.67 1.00 9.80 20.89 1533.06199.01 14.34 14.60 2.88 11.54 1633.03 1523.45 0.91 428.77 23.65 709.73 10.66 1592.10 88194.82 1660.00 2802.22 23.58 14.60 10.98 1.45 0.44 53.91 1619.03 10.57 7.30 0.56236.78 8.95 90.9 3.19 0.42 1523.45 148334.63 14.70 1738.52 2.57 756.37 9.16 10.57 2.82 0.67 3.97 457.85 2802.22 1688.81 2.64 43.00304.23 1.66 95.7 1732.65 6.34 2.57 3.56407.54 602714.68 9.70 34.79 0.52 1.56 2.96 2.21 1738.52152.90 96.0 8.55 192328.12 1.34 0.25 896.89 9.95 9.07279.59 220065.69 423.38 6.34 2.42 1688.81 1.23 0.28 1732.65 0.55 4.34 1.98 5.65 4.58 1.39 0.22 89.3 15.53 54317.83 8.55 13.53181.40 0.83 9.95 2.14 0.27 92.5 1.49 97.0 354.56 709.73 5.32 1441.44 1.21 0.24 88.5 0.96 25994.09 2.61 4.07 53.91 0.17 0.91 159040.18 13.49 0.95 2.38 0.52 17.91 1603.06 2.00 0.98 1286.63 79.1 1.86 0.29 0.31 21.19514.30 0.94 3.06 1454.19 17.23 18.20 1565.71 14.16 0.89 1.78 8.32 1365.52 84206.34 33.07 12.84 1628.54 2.55468.89 13.22 1311.89 3.28 0.29 0.98 22.88 0.84 3.34206.38 12.63 241248.53 1539.77 1.76 1472.87 1.31 1631.66 7.19 0.25 9.84 1398.42 13.29 3.01 36943.16 19.15 1.94 36.81 0.57 0.98 1661.61 2.65 15.01 0.50 17.35 11.19 0.17 1353.40 1.81 1623.37 1700.51 5.75 1504.32 0.36 1472.87 0.83 0.51 17.17 8.17 43.23 0.98 1448.94 17.35 1.20 21.50 10.80 4.97 0.17 1.49 0.92 1661.61 2918.38 1.91 97.9 7.91 0.74 1648.57 1353.40 0.99 1.77 12.82 1039.27 2.79 8.17 1786.42 10.80 19.36 1504.32 1.58 0.07 24.97 2657.92 1448.94 0.87 11.50 2.78 96.5 0.35 95.1 7.91 12.82 2947.70 1.22 41.67 1022.08 3.69 104.1 9.45 0.64 1680.83 1039.22 0.74 94.2 0.70 14.93 8.08 7.02 2695.36 1786.42 0.94 0.17 8.51 10.20 408.92 9.45 2.93 18.29 1029.49 1920.10 2967.76 1680.83 14.61 0.23 91.3 1.17 11.55 1039.08 11.72 10.20 0.95 2723.55 0.08 6.86 409.10 96.6 2.71 1938.44 1014.13 0.98 1045.27 10.59 2967.76 0.91 16.75 10.96 5.06 1312.97 1039.08 6.38 0.31 2.71 17.92 10.59 2723.55 81.50 1033.54 100.0 496.87 98.3 410.12 1045.27 1958.09 5.06 17.92 1351.36 7.93 4.34 97.6 74.64 97.8 52.49 4.41 1074.87 504.45 408.92 1958.09 1412.62 14.61 11.66 4.41 7.28 99.7 28.49 98.1 1074.87 538.91 1412.62 7.28 28.49 94.3 60.98 92.9 496.87 4.34 92.2 177.34 60917.88 2.30 12.30 1.01 2.32 2.19 0.21 1.95 0.89 1210.81 21.48 1217.27 15.55 1228.72 19.83 1228.72 19.83 98.5 DC1 (Permian sandy limestone) ( DC1-067 DC1-068 DC1-069 DC1-070 DC1-071 DC1-072 DC1-073 DC1-075 DC1-076 DC1-078 DC1-079 DC1-080 DC1-082 DC1-084 DC1-087 DC1-088 DC1-089 DC1-090 DC1-091 DC1-092 DC1-093 DC1-095 DC1-096 DC1-097 DC1-100 TRSS-002 TRSS-003 TRSS-004 TRSS-005 TRSS-006 TRSS-007 TRSS-008 TRSS-010 TRSS-011 TRSS-012 TRSS-013 TRSS-014 TRSS-015 TRSS-016 TRSS-017 TRSS-018 TRSS-019 TRSS-021 TRSS-022 TRSS-023 TRSS-024 TRSS-025 TRSS-026 TRSS-027 TRSS-029 TRSS-031 TRSS-032 TRSS-033 TRSS-034 TRSS-035 TRSS (Permian silty limestone) TRSS-001 Sample number

Geosphere, December 2012 1447

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al. ) continued ( Depo age High error High error Depo age Depo age Depo age Depo age (%) Comments Conc ± (Ma) (Ma) Best age ) ± (Ma) continued Pb* 207 Pb*/ 206 ) a M ( ± s e (Ma) g a t U n e 235 r a p p Pb*/ A 207 ± (Ma) U* 238 Pb*/ 206 corr. error ± (%) U 238 Pb*/ 206 s ± o (%) i t a r e U* p o t 235 o s I Pb*/ 207 ± (%) Pb* 207 Pb*/ 206 ) TABLE 2. DATA USED TO CALCULATE U-Pb AGES OF DETRITAL ZIRCONS FROM PERMIAN AND MIOCENE ROCKS ( ZIRCONS FROM PERMIAN AGES OF DETRITAL U-Pb CALCULATE TO USED 2. DATA TABLE Pb U/Th continued 204 Pb/ 206 U 54.39 34367.68 2.20 12.67 2.38 2.05 3.84 0.19 3.02 0.79 1114.00 30.91 1133.13 26.25 1169.94 47.06 1169.94 47.06 95.2 97.01 16634.16 1.1187.13 16.96 35166.30 2.11 4.00 12.49 0.71 2.6913.60 6.44 2.21 19429.7377.51 0.83 0.09 2.98 36072.6981.39 12.46 0.92 5.05 0.78 0.20 22828.92 12.63 4.25 542.72 7.21 1.27 26.28 0.43 12.50 1.12 1177.80 2.29 547.11 13.71 2.55 27.24 1.95 9.25 1185.23 20.82 1.82 565.37 4.47 0.21 1198.80 87.08 4.10 5.79 0.18 0.63 53.05 542.72 1215.08 4.33 26.28 0.16 1198.80 0.97 64.09 53.05 96.0 1059.43 3.21 0.78 98.2 1210.61 42.29 65.48 983.26 1098.20 29.24 30.02 1202.65 1051.89 142.30 1175.88 26.85 1202.65 142.30 22.22 101.0 1197.28 1175.88 22.22 50.36 90.1 1197.28 50.36 82.1 90.66 40472.76 1.71 9.82 1.37 3.8984.66 47913.62 1.72 2.49 0.28 9.00 1.05 0.61 1.02 1575.42 14.70 4.93 1610.83 13.92 1.72 1657.41 0.32 25.30 1.39 1657.41 0.81 25.30 1798.75 95.1 21.83 1807.43 14.55 1817.42 18.49 1817.42 18.49 99.0 116.43 92945.99 9.88 4.48 0.20 17.51 0.78 0.57 0.76 0.97 2906.01 17.71 2963.42 7.51 3002.61 3.15 3002.61 3.15 96.8 (ppm) 237.90 47059.86 2.68 9.85 5.45 4.24 7.29 0.30 4.85 0.67 1704.56 72.68 1681.29 59.99 1652.36 101.00 1652.36 101.00 103.2 541.13183.81 1689.67181.23 1.74642.17 634.62 1.52 605.15 31.27 1731.66 1.46 1.07 13.74 35.54 8.14 15.47 71.03 0.01 47.94 77.49 0.02 37.36 0.03 0.02 73.12 0.00 51.08 78.27 0.00 11.52 0.31 0.00 17.36 0.00 0.24 13.94 17.65 11.01 0.35 0.14 14.27 1.60 11.85 14.12 2.47 2.09 9.65 1.55 22.34 3.59 16.16 31.15 19.66 15.67 15.24 -966.68 1008.37 1072.71 1692.79 1997.77 763.12 13.94 911.36 2000.86 14.27 1.60 2.47 11.85 14.12 2.09 1.55 241.37 223101.41 2.79176.69222.43 26225.58193.74 9.62 1.48 48423.97364.59 2.87 63640.85 167367.96 13.38 3.69 1.59 0.30194.89 13.75341.00 99370.26 8.49 10.91 1.06 3.88 53882.11 4.21 1.12164.55 3.13240.55 0.41 43142.78 0.60 1.76 9.35181.07 1.28 14.28 1.24 43917.51 1.68181.07 2.43 69272.82 3.92 2.94 3.14 12.82 2.66 0.28 0.29 70583.93 0.73234.50 1.49 12.32 2.96460.59 1.24 0.17 54345.04 5.17 0.96 9.36 1.25134.59 0.97 196130.54 4.50 2.40 0.17 1.49 9.87 1.00 0.82 1660.41 2.74 42455.46 0.24291.13 0.25 0.93 10.04 1.32 0.38 0.98 1.80 18.16 2.05 0.66 1.14 9.83 1015.15 0.64 29946.92 2.31 5.15 0.74221.39 1676.37 12.65 2.08 1000.91 1.00 25.73 0.78 0.31 0.46 4.39 1.46 112650.79 0.15 10.48 1393.94 1.27 1430.92 0.16 9.09189.51 3.91 1.24 1029.84 12.41 1.78 1.13 64.55580.81 129394.67 0.87 0.19 0.99 1.08 9.55 19.00 1002.61 3.60 1696.39 1.61514.21 0.77 244409.45 9.41 0.21 1.44 1618.06 3.93 1717.04 1.94 0.96 1442.87 0.77 9.49 65422.23 2.00 1061.17 925.31 0.30 26.76 41.82 0.53 5.57 4.05 9.57 4.59 0.93 0.28 11.04 0.41 7.37 0.75 0.93 1124.04 1696.39 7.51 1006.32 1731.14 1.82 21.25 1.01 1923.27 3.68 1209.49 0.26 0.94 5.57 9.12 1.29 0.23 1061.17 7.95 14.93 1460.52 0.28 0.89 926.49 0.34 22.75 10.23 4.33 21.25 1680.78 97.9 4.68 4.03 0.18 7.38 1131.81 1590.70 1006.32 14.98 0.99 95.7 1748.20 11.45 1215.34 6.91 0.23 0.91 22.75 4.17 1923.27 18.13 10.00 0.98 1.38 2.84 1500.63 1460.52 3.50 0.16 1709.92 99.5 7.38 8.79 0.95 11.45 1593.20 5.18 53.92 1615.87 929.33 4.45 1.18 1146.75 1086.69 72.5 4.58 0.30 8.95 98.0 12.86 3.45 1748.20 0.98 1225.74 11.63 1549.53 35.02 14.98 5.18 24.77 1620.15 1.32 0.29 1745.78 0.86 32.23 978.66 0.23 0.96 1648.80 16.19 1115.91 98.2 1146.75 929.33 41.61 7.50 24.77 14.98 1670.78 1225.74 1.16 24.91 1616.84 0.29 7.02 3.44 0.98 16.19 11.93 98.0 19.46 1.00 1053.46 99.6 1655.32 1745.78 1639.73 1648.80 98.7 1173.29 0.83 1322.08 30.71 8.62 11.93 1699.85 7.02 0.97 16.82 41.09 1616.84 96.5 3.05 22.27 11.42 1661.22 96.3 1211.97 1668.64 8.62 1366.84 1655.32 12.20 1173.29 1735.86 22.27 92.8 3.05 9.70 18.95 25.96 1720.98 92.6 96.2 1211.97 1705.19 7.50 18.95 1437.50 7.15 1735.86 80.7 1794.45 4.23 7.50 6.57 1705.19 96.3 1437.50 4.11 4.23 6.57 1794.45 96.2 92.0 4.11 92.6 525.46 112646.94 8.84121.72161.08 63690.98 9.44 1.53 35011.51240.42 2.82154.24 171535.48 9.89 1.62 0.38319.80 11.40 40562.84207.23 113621.05 0.90 1.34343.00 139734.95 5.90 0.82 4.10 3.77 0.82675.23 64190.95 9.94 10.68 13.48539.15 174909.58 33.50 0.14431.07 312844.60 3.83 1.33 9.14 2.58 13.27 5.68239.63 184574.61 0.61 0.22 6.14 1.27176.38 125960.60 10.90 0.28 1.32 3.32 0.50 2.81 9.52 76138.92 0.74 3.11 3.23 7.95 1.70 1.27 1.04 1.47 0.27 11.29106.78 0.96 0.21 4.64 0.24148.99 1.81 1596.19 55139.25 5.77 1.32 9.93 1.04 0.16136.39 0.47 9.07 1.01 2.69 0.79 60523.58 0.28 18.02302.98 0.96 1.15 2.97 30143.85 4.26 1.06 1563.36 0.22 1.46917.69 0.25 106449.74 1654.84 7.12 1247.00 0.85 1.00 6.25 1.94 9.88 5.07 14.42674.79 266925.23 2.85 0.31 30.52 10.85 9.42 5.74 2.36 2466.09 1.31137.29 0.17 316768.06 0.69 11.69 0.99 0.99 1598.09 5.17 0.40 3.68 0.68 30.01 1295.32 9.33 0.78 1.03 49281.87 1730.11 2.03 1305.15 1438.95 11.31 0.76 10.63 0.90 2.57 0.52 0.29506.67 20.59 0.72 2514.38 10.69 1.43 1.63 67.81 16.84 1728.90 0.36 9.42 0.84 1036.25 0.37 0.23 3.95 1644.18 6.92 13.68 10.64 0.65 0.11 15.68 1435.65 1376.30 1464.25 527.73 2187.00 0.94 4.44 1730.11 0.66 0.17 7.24 1.02 2.45 0.27 2.01 44.38 0.97 15.13 30.29 10.26 1756.27 2553.59 1663.01 1.05 6.92 0.99 4.61 15.70 0.68 1049.74 2.93 1984.27 1644.18 1.07 19.03 2344.74 9.38 1353.25 92.3 1376.30 9.50 9.60 1634.69 3.94 15.13 3.31 1501.13 1.00 11.23 2.36 15.70 0.28 6.92 0.79 24.49 17.72 95.1 1686.41 3.39 1.32 1517.16 33.50 0.30 2553.59 90.6 1788.98 11.37 2011.79 0.21 4.12 0.57 126.79 1369.26 0.70 1077.92 2.36 2484.96 1634.69 0.31 5.69 0.66 0.93 1501.13 0.24 5.92 1.75 15.23 11.37 1568.09 3.67 0.87 96.6 9.13 0.02 1606.92 0.26 0.93 14.80 4.12 17.58 0.70 79.8 1715.62 75.34 1707.99 1788.98 1.32 0.88 2040.14 1394.31 1217.17 1077.92 9.90 0.26 95.9 2484.96 34.71 1.00 0.55 9.13 14.02 14.80 17.58 1749.82 40.73 0.95 1637.33 1386.90 4.47 1623.92 96.6 1.61 96.1 2.80 10.68 1719.47 88.0 5.36 1470.30 0.00 0.92 16.45 1257.66 1715.62 15.76 2040.14 8.48 1394.31 1751.11 1497.51 4.47 8.87 7.19 28.43 1388.64 9.08 1637.33 2.80 5.36 0.26 21.50 15.76 96.9 1646.01 6.60 10.01 1482.38 97.3 97.1 1733.47 1327.63 92.7 1501.97 13.87 14.51 4.47 1752.63 1391.30 13.70 27.72 9.56 1646.01 1.26 1327.63 14.51 1499.70 1733.47 6.83 1508.25 2.19 27.72 97.6 9.56 1752.63 15.73 1391.30 91.7 3.28 12.86 98.5 6.83 2.19 5.42 1499.70 1508.25 99.8 99.7 12.86 3.28 99.3 309.12 98.0 782.58 13.87 1.26 1287.06 118936.52 8.46 11.62 0.18 2.59 1.361070.03 0.22 84013.12 2.07 1.35 0.99 15.48 1275.17 15.61 0.42 1299.20 9.98 1.04 1339.11 0.73 3.49 0.12 1339.11 0.60 3.49 0.82 95.2 712.66 4.05 724.36 3.79 760.73 8.79 712.66 4.05 93.7 TRSS-063 AKR-09-2-018 AKR-09-2-023 AKR-09-2-031 TRSS-039 TRSS-040 TRSS-043 TRSS-044 TRSS-046 TRSS-047 TRSS-048 TRSS-049 TRSS-051 TRSS-052 TRSS-053 TRSS-054 TRSS-055 TRSS-058 TRSS-059 TRSS-060 TRSS-061 TRSS-062 TRSS-065 TRSS-066 TRSS-067 TRSS-068 TRSS-070 TRSS-071 TRSS (Permian silty limestone) ( AKR-09-2-004 TRSS-038 TRSS-072 TRSS-074 TRSS-075 TRSS-076 TRSS-077 TRSS-078 TRSS-079 TRSS-080 TRSS-081 TRSS-082 TRSS-083 TRSS-084 TRSS-085 TRSS-086 TRSS-087 TRSS-090 TRSS-091 TRSS-093 TRSS-094 TRSS-095 TRSS-097 TRSS-098 TRSS-099 TRSS-100 AKR-09-02 (ash-fall tuff) AKR-09-2-003 Sample number TRSS-036

1448 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex ) continued ( Depo age Depo age High error Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age (%) Comments Conc ± (Ma) (Ma) Best age ) ± (Ma) continued Pb* 207 Pb*/ 206 ) a M ( ± s e (Ma) g a t U n e 235 r a p p Pb*/ A 207 ± (Ma) U* 238 Pb*/ 206 corr. error ± (%) U 238 Pb*/ 206 s ± o (%) i t a r e U* p o t 235 o s I Pb*/ 207 ± (%) Pb* 207 Pb*/ 206 TABLE 2. DATA USED TO CALCULATE U-Pb AGES OF DETRITAL ZIRCONS FROM PERMIAN AND MIOCENE ROCKS ( ZIRCONS FROM PERMIAN AGES OF DETRITAL U-Pb CALCULATE TO USED 2. DATA TABLE ) Pb U/Th 204 Pb/ 206 continued U 46.39 23690.00 1.63 10.58 5.73 3.29 6.00 0.25 1.79 0.30 1451.48 23.20 1478.55 46.77 1517.61 108.19 1517.61 108.19 95.6 49.5827.08 12172.7432.52 2.30 15763.00 1.32 22888.62 2.49 11.55 4.4989.62 3.82 3.0982.47 41020.3756.80 2.86 0.98 49119.0866.77 1.14 1.09 30169.63 2.81 1.06 11.27 21251.13 17.49 2.59 22.59 4.89 3.27 5.69 1.39 2.21 9.92 2.57 1.00 0.24 1.12 0.57 2.87 2.10 1.06 0.63 15.16 0.33 1.98 12.06 0.90 3.36 1362.61 2.32 0.91 3.91 1.14 2908.36 13.07 3.23 3136.22 0.23 46.26 1358.17 0.54 2.39 57.73 2962.08 3.06 0.50 24.50 0.91 3209.41 0.54 21.21 0.2875.67 0.47 1357.50 3.03 24.97 1351.16 0.94 2773.38 27811.48 37.46 2998.76 1.15 1.19 2602.50 0.48 12.20 3255.47 59.7074.79 1373.28 64.84 15.82 1597.86 1351.16 2825.07 10.44 28265.18 25.30 17.15 59.70 2998.76 16.24 2609.11 1.69 10.87 100.8 15.82 3255.47 30.27 1615.61 1397.89 17.15 2.8119.84 97.0 11.35 2862.1543.70 19.33 96.3 2614.23 26.62 9501.1060.07 24523.93 3.45 16.34 1.74 1.97 1397.89 1638.80 0.54 51261.56 18.56 26.62 2862.1577.73 1.25 10.94 16.34 2614.23 97.1 38.94 3.89 52427.85 2.99 5.31 18.56 96.9 1.52 1638.80 5.68 99.6 38.94 7.27 0.26 2.55 1.06 97.5 8.7426.24 0.79 2.69 0.69 2.85 0.25 10911.86 13.45 1.47 1496.53 1.65 11.84 1.61 7.80 35.92 0.63 2.73 9.61 5.16 2.95 1516.35 1420.08 0.23 0.52 20.54 30.65 5.50 0.49 2.15 2.82 1405.71 2.52 0.36 1544.12 0.92 2.85 19.39 1313.38 0.33 0.96 4.14 2691.30 52.90 33.50 2562.44 55.43 1383.96 1.38 1544.12 0.64 5.90 60.21 1367.97 52.90 2711.85 37.89 1824.66 58.66 96.9 2592.05 25.84 0.29 1383.96 21.90 27.67 37.89 1454.26 1846.60 102.6 2727.18 2.13 0.36 2615.27 138.48 18.27 17.44 1635.59 1454.26 138.48 13.15 2727.18 30.77 1871.39 90.3 17.44 2615.27 1662.69 13.15 98.7 29.72 48.29 98.0 1871.39 29.72 1697.08 97.5 101.46 1697.08 101.46 96.4 112.07 77374.46 3.46 4.97 0.41 14.62 0.84 0.53 0.74 0.87 2726.85 16.40 2790.97 8.02 2837.63 6.67 2837.63 6.67 96.1 (ppm) 605.35198.37 202572.69 3.71147.91 9198.30258.25 28108.26 2.89 11.92797.30 4.46 89255.33273.24 182388.13 1.99 13.50 1.73 112603.94 13.51 0.76 6.82 7.82 12.18 1.69 2.32 2.33 8.81 0.55 0.49 1.63 1.74 1.67 0.86 6.27 2.40 3.15 0.20 3.03 5.07 2.13 1.96 0.16 1.49 0.17 0.89 1.43 2.66 0.36 1181.66 0.21 1.95 0.84 0.64 16.08 0.32 2.06 1.89 953.53 1014.54 0.97 0.97 1220.76 1.14 23.55 18.28 1961.53 1240.20 0.80 11.87 34.84 21.37 1023.21 1810.86 981.32 1290.53 17.98 19.55 2014.04 1242.88 19.80 18.66 14.02 1831.63 14.77 1041.79 1043.99 1290.53 12.13 2068.31 1247.50 14.77 46.90 34.00 91.6 1855.30 1014.54 9.62 9.50 953.53 18.28 23.55 15.62 2068.31 1247.50 97.4 91.3 1855.30 9.62 9.50 15.62 94.8 99.4 97.6 532.57 700.56 1.38197.27 34.85104.89513.36 607.70 42.57 0.91 213.61 1.50 644.72 1.91 8.35 0.01 1.16258.30 21.82 43.60 74.78222.16 457.98 78258.76 2.06 44.63 55741.78 0.00 4.16 0.03 0.25 9.86 9.43141.06 0.01 11.36 74.96 0.22 458.05158.15 52385.05602.41 45.06 2.10 0.51 72178.77 12.81 0.00 1.12 0.00 195477.38 3.00 1.22 1.21 0.00 8.98 5.23 7.96 3.94 0.07 0.02 2.88 9.05 9.03 6.27 0.14 7.96 0.57 1.44 13.06 13.35 2.07 0.68 0.37 3.46 13.14 0.68 1.06 0.28 4.87 0.24 0.82 -1297.78 5.00 224.24 4.92 33.42 1.35 1400.71 1537.28 1.74 0.94 1.29 0.84 24.65 13.00 1.91 1600.25233.92 2.11 12.81 1374.50 0.32 19.15636.06 5.82 1952.03 0.00 1.21 47742.85 21.57 0.33229.03 2.35 1640.27 0.32 69101.63 1200.66 1622.31 1.16252.88 154396.15 1377.84 1.39 0.90 1.79 1.79 -11.82508.20 11.70 13.00 2.07 0.93 90097.09 13.06 15.61 13.35 1775.96357.09 0.98 1128.82 17.03 1.73 86393.29 0.68 1828.70 1.06 18.02184.90 1651.04 8.52 1.95 1800.22 87427.18 1383.01 2.29 28.47 13.14 3.25 65441.11 32.57 1797.01 9.36 2.00256.35 13.63 2.05 0.82 9.45 1818.63 21.48 0.63 10.88 1805.05 12.59 72749.03 1.99 1651.04 1383.01 16.18 3.34 0.49 17.77 0.71 9.34 21.48 0.78 9.45193.75 1821.52 5.52 0.97391.39 99.4 1807.10 2.49 96.9 40894.57 1810.61 9.41185.07 4.46 10.28 3.63 2.44 1.29 17501.32 1.71 12.33 1.66 2.21 1821.52 0.19 92034.63 2.23 6.72 10.28 13.45 2.68 0.75 1807.10 0.09 1.64 4.59 1.81 12.33 10.91 1810.61 0.97 0.34 97.5 133.11 0.39 101.2 1.76 10.01 3.03 6.72 0.30 1.68 0.83 4.61 1109.52 1.54 0.17 46379.76 1.90 99.4 1.14346.03 0.93 2.97 0.20 543.54 1.57 0.90 9.89379.53 115509.85 1892.30 1.63 18.80 0.95 1.08 1.81 0.31 15.80123.00 0.90 106933.62 1.48 25.26 2.57 9.32 1703.96 1112.77 4.17358.19 0.84 1009.57 11.10 68232.06 4.00 1.39 0.31 23.46 16.84 545.99 2.29 1903.59 0.63 1197.28 0.74 94199.94 15.24 13.66101.76 1.86 1.04 0.54 15.34 16.13 14.30 1723.04 1746.53 0.77 0.58 1.67 1119.14 1014.13 0.18 0.72 53273.30 9.98 21.34 13.63 1191.88 2.22 0.20 0.78 1915.91 11.59 9.68 1764.97 556.22 4.65 45.77 1.55 0.29 12.37 1748.36 3.05 11.89 0.68 1746.29 3.00 1.46 1119.14 1023.97 8.45 11.27 43.67 15.82 0.79 45.77 1.73 1050.63 0.69 1.40 1.92 1751.50 1182.13 1915.91 0.84 1.02 1193.76 99.1 9.05 15.03 15.79 543.54 11.27 3.95 1750.53 1645.39 2.70 15.80 8.98 15.92 19.09 1.39 1746.29 0.31 1009.57 98.8 4.08 1050.63 20.32 0.25 15.24 97.7 9.05 1182.13 23.55 1292.52 1735.45 3.12 14.97 19.09 1.85 0.17 98.6 5.40 1634.95 97.6 1750.53 0.96 1.71 0.84 13.57 101.3 23.55 0.82 13.80 13.54 1050.63 1760.95 0.29 1.14 1415.78 99.8 3.10 0.82 1460.54 1735.45 0.29 28.46 13.80 1621.54 33.87 10.69 0.87 1021.43 0.28 101.7 1757.59 21.75 1.56 0.33 1050.63 10.80 1420.58 0.92 16.83 15.03 1622.10 1460.54 16.08 100.0 21.75 1622.45 1020.85 1.51 1621.54 12.52 7.82 0.49 16.83 22.44 81.7 1753.58 8.93 1624.58 101.5 1842.39 1427.77 1649.55 24.20 25.29 9.90 1019.59 13.93 11.11 1884.49 1753.58 1627.77 1427.77 15.87 9.90 26.53 1684.22 11.11 100.4 1021.43 55.70 99.2 10.80 1931.19 12.66 1627.77 100.2 55.70 1684.22 48.41 12.66 99.7 1931.19 96.3 48.41 95.4 1194.74 2282.36 1.56 18.93 29.23 0.01 29.34 0.00 2.59 0.09 12.26 0.32 13.98 4.07 321.14 677.07 12.26 0.32 1234.25 5528.862625.22 1.36 9348.71 30.07 0.84 21.94 33.752495.46 10.291647.58 0.01 2217.77 1.17 4341.142304.70 0.01 34.20 1.43 15.49 6162.05 10.63 0.00 20.69 1.08 27.04 5.55 0.00 25.64 30.70 0.16 2.64 0.02 23.54 0.25 12.97 0.01 27.08 0.72 13.46 0.01 32.27 0.36 0.00 23.56 9.33 0.00 1.52 13.25 0.06 3.18 9.93 0.00 0.31 1.40 13.47 -853.05 0.93 0.04 12.44 0.21 991.17 -25.10 1.23 13.37 249.83 12.97 18.73 0.12 0.72 12.98 13.46 5.03 4.16 0.36 11.27 759.52 2.64 115.56 580.24 739.50 -416.99 13.47 623.00 12.44 0.21 1.23 13.37 0.12 1016.80 1530.44 2.07 22.89 34.81 0.01 34.90 0.00 2.42 0.07 13.05 0.32 12.32 4.27 -128.00 883.09 13.05 0.32 1806.19 5532.75 0.98 21.75 9.08 0.01 10.01 0.00 4.21 0.42 13.49 0.57 13.40 1.33 -3.40 219.45 13.49 0.57 AKR09-1A-035 AKR09-1A-041 AKR09-1A-043 AKR09-1A-081 AKR09-1A-096 AKR09-1A-102 AKR09-1A-001 AKR09-1A-020 AKR09-1A-026 AKR09-1A-002 AKR09-1A-003 AKR09-1A-004 AKR09-1A-005 AKR09-1A-006 AKR09-1A-007 AKR09-1A-009 AKR09-1A-011 AKR09-1A-012 AKR09-1A-014 AKR09-1A-015 AKR09-1A-016 AKR09-1A-017 AKR09-1A-021 AKR09-1A-022 AKR09-1A-023 AKR09-1A-024 AKR09-1A-025 AKR09-1A-027 AKR09-1A-028 AKR09-1A-029 AKR09-1A-030 AKR09-1A-033 AKR09-1A-034 AKR09-1A-040 AKR09-1A-044 AKR09-1A-049 AKR09-1A-050 AKR09-1A-051 AKR09-1A-052 AKR09-1A-054 AKR09-1A-056 AKR09-1A-059 AKR09-1A-060 AKR09-1A-061 AKR09-1A-062 AKR09-1A-063 AKR09-1A-064 AKR09-1A-066 AKR09-1A-067 AKR09-1A-068 AKR09-1A-069 AKR-09-02 (ash-fall tuff) ( AKR-09-02 (ash-fall tuff) AKR-09-2-048 AKR-09-2-049 (sandy lens in conglomerate) AKR-09-1A AKR09-1A-008 AKR-09-2-043 AKR-09-2-036 Sample number

Geosphere, December 2012 1449

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al. ) continued ( Depo age (with AKR-09-3) High error (%) Comments Conc ± (Ma) (Ma) Best age ) ± (Ma) continued Pb* 207 Pb*/ 206 ) a M ( ± s e (Ma) g a t U n e 235 r a p p Pb*/ A 207 ± (Ma) U* 238 Pb*/ 206 corr. error ± (%) U 238 Pb*/ 206 s ± o (%) i t a r e U* p o t 235 o s I Pb*/ 207 ± (%) Pb* ) 207 Pb*/ 206 continued TABLE 2. DATA USED TO CALCULATE U-Pb AGES OF DETRITAL ZIRCONS FROM PERMIAN AND MIOCENE ROCKS ( ZIRCONS FROM PERMIAN AGES OF DETRITAL U-Pb CALCULATE TO USED 2. DATA TABLE Pb U/Th 204 Pb/ 206 U 89.75 241.66 30.34 20.75 23.13 0.12 23.36 0.02 3.24 0.14 119.49 3.84 118.98 26.23 108.7387.98 552.65 17525.22 119.49 1.19 3.84 109.9 32.43 11.0933.13 23264.86 1.44 18625.31 1.95 1.2140.69 13.49 22429.55 3.00 6.91 1.40 5.0987.79 2.12 11.36 1.2152.64 73394.63 1.97 1.54 0.24 12622.20 4.7679.26 8.57 2.74 5.20 0.85 27681.15 9.9385.75 0.40 13.85 1.09 1.44 3.09 1392.93 0.19 37278.67 1.12 1.75 10.59 6.41 0.43 4.84 4.78 1.05 0.20 1407.36 8.14 0.78 4.03 1133.51 0.68 0.25 0.54 16.16 1.82 10.94 2303.32 1.16 0.37 3.65 1429.26 15.20 0.08 9.19 4.94 1103.81 1462.44 34.99 2292.95 37.15 0.29 6.05 0.18 3.00 1429.26 4.87 13.12 1045.74 37.15 3.20 1.02 0.88 2.52 1430.19 0.43 0.21 97.5 2283.72 102.70 1640.59 36.67 1085.01 1045.74 2.92 0.36 102.70 46.36 20.84 0.97 10.23 108.4 1382.50 2283.72 1639.27 2293.43 2.23 20.84 1054.37 0.89 56.30 29.70 100.9 91.56 32.43 1967.78 1382.50 2356.75 37.83 1637.56 91.56 27.44 105.8 991.46 1982.90 32.58 21.92 98.37 2411.99 1637.56 32.58 991.46 100.2 1998.68 11.58 98.37 2411.99 109.4 20.66 11.58 1998.68 95.1 20.66 98.5 36.7321.87 23548.43 0.98 15694.31 1.17 5.60 4.76 0.76 1.8969.51 12.37 17815.07 15.88 0.91 2.54 3.11 13.3456.40 0.50 8900.29 0.5551.24 5.14 1.37 2.42 31321.51 0.95 2.47 1.37 0.79 13.10 2626.52 1.83 2819.00 52.31 9.09 56.36 4.20 5.26 2633.25 2869.78 23.88 1.70 0.1874.82 1.97 29.69 2638.42 35843.76 1.1380.68 4.86 2905.61 1.99 4.90 0.22 12.67 25158.60 1048.92 30.60 2.53 2638.42 1.99 9.97 0.19 10.97 12.67 2905.61 30.60 12.93 99.5 1055.02 2.52 0.32 2.20 0.51 97.0 34.56 1105.27 1.04 2.89 0.52 25.62 3.85 1067.70 1791.44 1.98 1104.89 103.41 16.33 3.07 33.02 1048.92 1794.85 10.97 3.22 0.28 16.78 1104.16 98.2 0.19 2.13 1798.81 84.10 0.70 1.44 1104.16 1582.34 0.45 30.88 84.10 29.95 100.1 1099.65 1798.81 30.88 14.54 1602.84 99.6 24.73 1110.06 21.77 1629.87 1130.54 40.97 1629.87 57.48 40.97 1130.54 97.1 57.48 97.3 211.24 97999.04 3.15 12.83113.54 3.93 350.41 2.39 2.10 -2.36 4.44 203.47 0.20 -0.10 2.08 0.47 203.57 1152.64 21.91 0.00 1150.13 6.33 0.03 30.60 10.63 1145.44 0.67 78.10 1145.44 -102.82 78.10 -223.83 100.6 0.00 1971.12 10.63 0.67 (ppm) 182.13432.02 40529.38221.48 128584.26 1.90 2.51 52045.06 13.13 2.87 11.07233.78181.87 13.41 72802.52 1.28 2.07 73644.33 0.73287.76 3.06 0.83299.85 37861.82 1.88 6.18522.24 2.74 12.03 2.33 93842.47 2.28 30222.92 1.87 1.66 2.48 1.01 3.41 9.58 1.85209.16 11.09 102796.26 1.32 0.18 8.63 0.73133.77 0.22 8.90 0.40 2.49 0.73 1.06 0.18 53353.12 3.34210.81 0.64 9.92 1.69 0.62 3.14 0.98229.04 4.17 2.18 1061.07 1.03 16536.57 3.00 1282.24262.47 0.78 158806.93 3.12 11.67 10.40 1.85 0.40 0.43251.56 4.57 38.79 1078.72 0.22 83804.04 1.94146.10 1.11 1073.72 10.99 1.71 12345.40 10.27 1339.43 2.97 1.30287.09 105111.79 3.92 1.05 1.15 0.95 0.91 3.86 11.01 1.68 0.29194.33 0.53 25.41 1071.61 0.24 72161.12 9.94 2165.01 1.42131.29 10.96 3.66 1269.38 25716.13 2.74 1099.49 1.90 0.29 0.46 54.69453.07 8.77 1.66 1432.01 8.85 1.71 0.83 0.98 64289.44 13.25150.10 0.75 12.85 3.40 0.49 41030.53 2327.68 2.63 25.55 1640.19 0.66 2.91240.37 1057.18 1.63 1270.51 21.04 13.86 0.73 1394.02 0.28 0.73 42603.09 4.70 0.60 1099.49 27.49316.32 28.67 14.08 1.37 92581.00 1432.01 10.41 15.77 25.55 1622.27 0.58 150405.40 3.93 16.69 8.62 18.25 13.86 1.72 1.60 0.23 1668.48 2.80 1.54 2.57 0.97 96.5 2473.54 1407.97 0.58 1057.18 9.53 5.10 89.5 1272.43 5.71 3.10 15.88 16.69 1579.44 0.99 0.21 1.16 2.11 5.91 2.00 0.60 8.43 0.60 1743.80 102.0 17.03 3.09 5.75 22.45 13.49 36.02 1704.25 2.23 1346.39 0.67 2473.54 8.50 1.50 0.28 7.56 1272.43 1.47 0.99 1429.12 2.04 17.03 1604.91 0.39 0.22 11.98 0.95 0.52 36.02 0.47 3.06 1228.26 0.33 87.5 7.33 13.38 11.12 1.05 3023.95 1892.76 99.8 13.97 3.16 1340.37 1.05 0.20 0.91 95.04 10.22 1704.25 0.34 2.11 35.56 10.91 1429.12 2.15 0.46 12.13 1638.50 1609.02 7.33 11.12 0.96 0.91 13.97 1310.03 1297.31 1.96 0.15 3140.53 14.99 0.96 1.40 1892.76 1826.54 96.2 3.00 0.07 97.5 12.37 63.49 1330.74 1.53 11.12 0.98 8.02 14.97 1155.73 0.57 0.46 34.16 1620.33 0.18 1356.84 2439.37 85.7 1638.50 0.68 0.44 20.74 1446.49 25.12 0.46 0.32 1836.92 3215.89 0.62 9.39 8.02 60.95 23.17 918.52 1330.74 0.68 1151.25 1.34 18.93 27.10 25.12 432.06 96.4 1.45 0.96 2714.30 2440.71 4.92 1635.03 14.07 0.95 101.2 1451.90 7.33 1446.49 2343.01 2.82 12.56 28.89 1848.69 27.10 2418.27 3215.89 930.24 26.37 55.39 1142.82 9.03 84.9 7.33 29.24 2533.42 427.58 2925.82 10.84 19.24 1451.90 2455.27 1635.03 94.0 55.39 11.44 2515.39 1848.69 8.47 7.36 9.03 12.94 10.84 1142.82 89.4 9.31 14.19 958.09 11.44 98.4 98.8 2608.51 2925.82 101.1 2549.58 403.48 2594.71 63.46 9.31 11.11 44.77 83.4 6.55 958.09 2608.51 7.91 63.46 11.11 2549.58 432.06 2594.71 95.9 93.6 6.55 2.82 7.91 107.1 91.9 93.2 841.00272.88 121425.15 1.78303.13 57665.77353.11 105693.66 1.89 18.16 2.99 172123.44 2.34322.13 13.71 10.77678.73 112982.30 1.72 2.36 180604.83 8.15 17.19 2.13 0.66 10.74 0.51 8.97 0.80 1.76 3.18 0.67 3.05333.08 1.00 6.46 5.22 1.80 67555.28 0.07 3.29351.71 4.82 2.03 4.21 0.18235.23 165411.28 2.52 0.25 1.76168.89 0.83 1.76 47522.16 9.50 4.76 0.38579.64 1.70 3.67 1.68 44427.45 0.91 422.68139.53 0.93 5.20 3.17 53809.93 0.26 1039.60 1.87263.80 10.30 3.78 0.94 1429.30 39255.64 0.27 0.92 8.89120.88 45.75 2.15 1.63 40419.96 21.50 9.22 2086.16 0.29 0.92 421.40 13.13 3.38 1.37 58908.55 1030.62368.92 3.95 33.31 0.81 4.18 1452.07 11.86 0.27 1470.31 10.52 222981.68 33.81 13.36 11.47 0.46 1561.79 21.45 13.93 2040.56 6.40 0.75 3.38 19.06 9.29 0.62 414.38 4.78 17.88 1011.59 1478.43 1.94 1485.54 1.35 4.65 5.31 1676.48 1.77 13.74 0.27 38.49 1994.77 43.23 0.91 2.54 2.54 13.97 12.55 0.50 1039.60 1.17 2.52 1490.09 422.68 3.24 0.46 1485.54 1.72 14.27 45.75 0.96 10.30 1823.16 12.55 0.31 1.92 4.62 1.93 102.8 102.0 1994.77 0.99 1551.55 12.73 0.31 1.70 96.2 14.27 12.98 0.17 18.23 2.52 2629.51 44.75 1490.09 104.6 0.22 0.99 2.86 12.73 1.08 1823.16 41.38 1.55 0.21 0.92 1623.81 3.47 1730.95 18.23 0.90 98.7 1.83 1746.51 2705.17 0.31 38.30 27.38 0.95 85.7 1004.87 1.04 16.48 0.50 0.61 18.31 1274.91 14.44 1781.30 2.71 1718.75 1227.17 0.95 21.19 1758.60 3.44 21.31 1035.24 2762.17 11.67 0.99 1746.94 17.30 1284.33 9.80 11.18 2614.90 41.53 1840.79 1278.10 1718.75 14.09 4.78 17.30 73.86 1772.99 12.38 1753.17 1099.95 2762.17 90.3 4.92 1300.10 2678.44 23.89 4.78 1364.78 14.91 1840.79 8.43 32.69 95.2 12.06 1099.95 4.92 1760.60 1772.99 25.91 14.91 1300.10 2726.76 94.0 8.43 12.06 1364.78 91.4 16.61 25.91 98.5 98.1 1760.60 7.49 89.9 16.61 2726.76 99.2 7.49 95.9 1206.27 4246.04 1.15 18.97 33.25 0.01 33.45 0.00 3.64 0.11 11.34 0.41 12.91 4.29 316.27 775.64 11.34 0.41 JSR-09-6-021 JSR-09-6-022 JSR-09-6-024 JSR-09-6-027 JSR-09-6-031 JSR-09-6-035 JSR-09-6-036 JSR-09-6-037 JSR-09-6-038 JSR-09-6-039 JSR-09-6-040 JSR-09-6-042 JSR-09-6-043 JSR-09-6-045 JSR-09-6-046 JSR-09-6-050 JSR-09-6-051 JSR-09-6-052 JSR-09-6-055 JSR-09-6-058 JSR-09-6-059 JSR-09-6-060 JSR-09-6-061 JSR-09-6-062 JSR-09-6-064 JSR-09-6-067 JSR-09-6-068 JSR-09-6-069 JSR-09-6-070 JSR-09-6-001 JSR-09-6-032 AKR09-1A-072 AKR09-1A-073 AKR09-1A-075 AKR09-1A-077 AKR09-1A-082 AKR09-1A-084 AKR09-1A-089 AKR09-1A-090 AKR09-1A-093 AKR09-1A-094 JSR-09-6 (coarse sandstone) JSR-09-6-023 JSR-09-6-002 JSR-09-6-003 JSR-09-6-004 JSR-09-6-005 JSR-09-6-006 JSR-09-6-010 JSR-09-6-011 JSR-09-6-014 JSR-09-6-015 JSR-09-6-017 JSR-09-6-019 JSR-09-6-020 AKR-09-1A (sandy lens in conglomerate) ( AKR-09-1A JSR-09-6-073 Sample number AKR09-1A-071

1450 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex ) continued ( Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age (%) Comments Conc ± (Ma) (Ma) Best age ) ± (Ma) continued Pb* 207 Pb*/ 206 ) a M ( ± s e (Ma) g a t U n e 235 r a p p Pb*/ A 207 ± (Ma) U* 238 Pb*/ 206 corr. error ± (%) U 238 Pb*/ 206 s ± o (%) i t a r e U* p o t 235 o s I Pb*/ 207 ± (%) Pb* 207 Pb*/ 206 TABLE 2. DATA USED TO CALCULATE U-Pb AGES OF DETRITAL ZIRCONS FROM PERMIAN AND MIOCENE ROCKS ( ZIRCONS FROM PERMIAN AGES OF DETRITAL U-Pb CALCULATE TO USED 2. DATA TABLE ) Pb U/Th 204 continued Pb/ 206 U 67.76 32.94 1.89 3.56 71.93 0.09 74.67 0.00 20.06 0.27 15.09 3.02 88.24 63.19 3368.54 1245.80 15.09 3.02 14.40 11082.46 0.65 5.3665.43 28762.52 4.08 1.9140.62 10.09 13.07 33993.94 1.09 1.96 2.33 5.6170.44 0.51 3.90 45772.91 2.28 0.96 1.33 0.57 2.5062.82 2647.82 11.48 12.37 0.29 15810.30 28.98 2.67 3.1469.73 2.20 2684.42 1.55 0.62 155002.71 11.22 21.99 1.80 1618.54 0.50 2.69 22.14 2712.09 3.95 9.70 1.98 0.90 3.37 1613.65 31.52 2627.74 20.18 3.06 1.57 2712.09 0.22 42.80 31.52 1607.27 97.6 4.31 2633.22 1.22 4.18 0.36 20.70 36.53 1302.93 0.25 1607.27 2.39 14.42 2637.42 36.53 1.72 100.7 0.40 1325.93 0.29 15.93 1434.88 24.93 2637.42 1.80 22.15 15.93 0.75 1363.27 99.6 1423.33 1663.87 26.45 33.01 60.46 1363.27 1671.02 1406.07 60.46 19.62 95.6 75.72 1679.99 1406.07 75.72 102.0 29.0878.57 1679.99 29.08 17369.7677.07 1.06 99.0 20115.16 13.10 1.91 12.33 1.68 2.99 1.90 2.33 2.69 3.56 0.18 2.10 0.21 0.78 1069.29 1.93 0.54 20.71 1219.37 1080.74 21.45 17.89 1221.22 25.31 1103.90 1224.47 33.58 1069.29 58.83 20.71 1224.47 96.9 58.83 99.6 115.77 192.26 2.10 -0.07 9800.13 -2.71 9800.14 0.00 11.75 0.00 8.67 1.02 … … 0.00 1176.58 8.67 1.02 118.98 324.16 1.88 0.92 429.79 0.26 429.91 0.00 10.06 0.02 11.21 1.13 234.60 1428.83 0.00 1431.15 11.21 1.13 (ppm) 183.69 65919.22 3.21 5.10 0.43 13.63 0.63 0.50 0.45 0.72 2632.28 9.82 2724.59 5.95 2793.74121.33 7.11127.11 36.13 2793.74240.11 2.36 7.11168.18 203.44 1.36 94.2 319.18 0.16 1.57 588.26 1.53 7.49 1526.30 3.55 124.32 3.12 1.87 113.74 184.34 1526.30 0.03 0.06 0.00 125.81 0.08 113.97 4.80 184.89 0.00 0.00 0.00 19.28 0.00 0.15 14.19 7.28 14.33 0.06 0.68 0.08 10.42 1069.04 10.22 2.01 11.03 0.74 … 1.58 29.77 36.92 60.71 74.04 67.26 132.78 2143.67 --- 3372.13 1911.12 3571.11 292.44 1060.88 921.19 14.19 10.42 10.22 0.68 2.01 11.03 0.74 1.58 131.42 101592.87 3.07145.97185.49 22757.98545.81 5.46 1.72 33790.84480.41 152277.26 1.75 2.01 37550.17 5.95 0.38104.72 3.26 8.46125.45 9.17 63086.06435.32 12.94 1.72 11.86 0.52 48754.26 127793.10 3.57 0.55 1.02 0.40826.27 10.84 0.71 5.05 3.25109.17 219924.78 11.13 3.41300.14 5.23 8.25 33422.09 4.32491.09 0.51 1.07 2.93 0.53 73153.47 2.26 0.99 114705.82 9.62 6.10 1.23 2.44 0.34 0.61649.26 1.59 11.36 0.47 0.85 14.08120.29 158060.07 3.81 11.21 20.66 2.79 2669.15 0.32 0.58209.27 9.45 0.94 0.29 45549.21 5.95 1.18 0.88 1.35 13.22 2.88 10.67 0.19 92503.58 1.10 0.60147.40 1.84 3.09 2473.16 1.54 0.90 3.88 2675.38 0.92622.39 0.97 2.30 1.98 0.52 17140.50 19.32 2.87 9.47 1795.83 0.52 0.40 12.90 2.91 1628.35 0.22 47935.48 6.73 2.59 17.26 0.71 2509.72 1.44 1144.95 1.25 0.36 22.14 3.94 0.92 2.16 17.93 1.41 1.55 20.78 1858.27 2680.09 3.34 1.27 9.98 0.84 1.79 1696.92 18.58 2680.98 2.28 0.27 10.48 0.99 4.84 1199.67 1308.09 0.24 27.33 13.11 8.06 4.36 2539.42 6.28 1.73 1962.06 0.42 0.21 18.34 26.80 2.05 1.38 0.59 1928.86 2755.33 2680.09 1.81 0.27 38.54 1782.67 0.84 1351.76 1544.07 1.68 8.66 1.66 6.28 0.26 12.82 0.53 1299.60 0.94 1.37 1968.30 1366.75 4.75 9.80 13.74 0.45 2539.42 99.6 5.74 0.98 7.31 1229.88142.88 1.68 22.27 20.02 2810.25 63.19 1928.86 0.30 8.66 8.12 0.97 1542.19 1782.67 0.19201.10 18.83 1609.50 1421.51 1299.60 9.80 2.04 1373.40 97.4 1483.51131.92 7.31 65.19 1974.86 63.19 0.87 428.58 8.60 1296.50 93.1 0.51 0.07 5.76102.93 0.53 1.93 16.27 18.94 22.28 477.95 91.3 0.38 88.1 1622.55 2810.25 0.06223.60 1.16 13.09 1689.79 319.52 1421.51 6.00 1128.49 1491.21 0.96146.73 1696.20 8.60 22.98 39.23 2.16 1383.73 18.94 178.09 12.95 0.12 1974.86 1.50185.85 1.95 1408.55 13.51 256.48 95.4 5.32 5.55 0.74 92.0 10.66 6.00 1.31 1705.11 1728.40 22.72 426.09 403.80 65.90 1.42124.85 1.55 1130.67 378.32 11.58 1502.16 1696.20 691.05 164.92 99.4 1383.73 2.89 13.70 3.98355.17 10.66 1.75 16.92 22.72 -1.02 572.05 1408.55 30577.88 5.50 9.34334.22 0.02 116605.33 3.83 11.58 -3.12 91.0 1728.40 98.8 1723.98 7.54 52.23 1.26224.51 428.82 0.04 507.87 16.92 -4.91 87.3 2826.97240.23 376.25 1502.16 0.14 1134.84 66.34 234.08 11.08 28.41 36131.88 89.2 25.92 165.07 0.70 219.49 7.54 5.88 4.05 42390.09 0.10 -0.20 572.10 6.40 1723.98179.99 25.26 0.77 0.00 -0.06 98.8 25.92 443.50 2.36163.59 0.00 6.03 508.12 13.21 1134.84 38039.47 57.79 -0.08 0.25233.47 0.00 98.0 25.26 234.79 13.10 0.85 363.45 7.63 179.51 36925.18 7.14440.39 0.12 219.63 5.31 99.4 0.00 11618.05 0.04 2.90 2.42 0.00 1.06 6.87 426.09 13.58 0.86 11.23 31.07 60836.95 0.00 0.01 0.77153.63 15.65 18.74 5.71 11.69 3.98 24.74 0.00 0.03 18.26 0.43 378.32 3.60 9.43 46224.84 5.66 2.05 0.39 4.60 0.08 96.1 1.43 2.53103.08 9.42 5.50 13.63 1.50 7.96 1.94 0.67 1.62391.00 0.04 13.61 104.1 9.44 0.23 27913.69 0.65 5.52121.97 0.48 2.49 9.08 2.41 17.59 3.83 75810.07 1.72 6.24 3.36 1.48 0.73266.02 0.94 17.82 2.94 36.28 2.72 37099.87 2.52 11.57 1.66 134.81 0.30 0.76 3.99 0.25 11.49 0.20 33515.95 0.78 13.77 -224.12 58.90 903.45 1.42 3.40 13.62 0.51 1348.96 97.54 0.59 0.18 1.66 2523.55 -137.54 2.17 -65.36 13.21 4.96 2.25 33.13 53.80 2654.68 -159.81 0.90 1.74 … 0.90 6.51 1828.57 -82.18 0.53 0.17 6.34 10.31 5.49 -190.19 0.83 0.57 1.43 1426.25 1381.24 0.00 1155.80 434.58 0.21 3690.02 2.34 2542.74 1091.88 18.74 2.28 63.53 0.46 23.83 27.22 2.79 855.50 1516.83 0.67 2.05 0.00 0.49 1.44 0.16 1.43 0.00 1.77 9.43 5.36 3.64 0.66 1926.00 0.00 1131.99 1007.56 1557.43 5.27 1.87 1431.46 1561.30 0.81 2.30 13.61 0.67 1247.55 1281.24 1.23 9.42 0.47 47.70 21.23 17.00 1096.15 10.96 0.86 2558.06 2.59 3.36 2434.55 16.29 0.65 45.11 9.08 2.61 1015.08 106.77 9.44 1.97 0.23 6.27 2516.78 17.82 1086.59 980.24 1431.46 0.96 4.78 1.66 1277.41 0.17 1.48 4.10 21.83 1.42 45.11 2733.95 11.19 2469.97 1.51 0.18 40.68 1104.63 15.74 21.30 2558.06 0.65 94.2 61.70 2.45 0.44 40.37 1031.31 2516.78 1086.59 4.10 0.95 994.04 1345.13 1.15 15.36 40.68 1328.00 21.30 0.44 2463.32 2963.21 1036.78 98.7 4.75 18.30 106.4 51.10 1091.88 9.06 56.7 0.99 1063.32 23.51 19.00 31.38 1007.56 5.36 1351.62 61.76 2333.56 11.24 21.23 1024.60 1328.00 1033.15 98.8 2963.21 93.06 17.21 2457.82 31.38 97.7 1071.06 61.76 16.79 14.69 93.9 2519.42 17.25 82.2 1361.88 9.90 44.49 1025.47 980.24 2457.82 11.19 1086.85 33.55 9.90 2672.75 16.72 95.7 1361.88 100.5 46.93 33.55 1036.78 23.51 1063.32 98.8 8.18 101.1 11.24 2672.75 97.8 8.18 87.3 125.09 243.86 2.12 -0.94 338.51 -0.24 338.54 0.00 4.31 0.01 10.72 0.46 -283.56 … 0.00 2034.25 10.72 0.46 1455.90 113502.65 0.45 15.92 0.68 0.97 2.04 0.11 1.92 0.94 681.81 12.44 686.52 10.18 702.00 14.46 681.81 12.44 97.1 AKR-09-3-012 AKR-09-3-020 AKR-09-3-022 AKR-09-3-038 AKR-09-3-056 AKR-09-3-062 AKR-09-3-071 AKR-09-3-075 AKR-09-3-076 AKR-09-3-079 AKR-09-3-085 AKR-09-3-100 AKR-09-3-101 AKR-09-3-001 JSR-09-6-072 JSR-09-6-074 JSR-09-6-077 JSR-09-6-079 JSR-09-6-080 JSR-09-6-081 JSR-09-6-082 JSR-09-6-083 JSR-09-6-084 JSR-09-6-085 JSR-09-6-086 JSR-09-6-087 JSR-09-6-088 JSR-09-6-089 JSR-09-6-09 JSR-09-6-090 JSR-09-6-093 JSR-09-6-094 JSR-09-6-095 JSR-09-6-096 JSR-09-6-097 JSR-09-6-098 JSR-09-6-100 AKR-09-3 (muscovite-rich sandstone) AKR-09-3-003 AKR-09-3-006 AKR-09-3-007 AKR-09-3-008 AKR-09-3-009 AKR-09-3-017 AKR-09-3-018 AKR-09-3-023 AKR-09-3-027 AKR-09-3-028 AKR-09-3-029 AKR-09-3-030 AKR-09-3-031 AKR-09-3-032 AKR-09-3-034 AKR-09-3-036 JSR-09-6 (coarse sandstone) ( JSR-09-6-071 AKR-09-3-004 AKR-09-3-005 Sample number

Geosphere, December 2012 1451

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al. ) continued ( Depo age High error Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age Depo age High error (%) Comments Conc ± (Ma) (Ma) Best age ) ± (Ma) continued Pb* 207 Pb*/ 206 ) a M ( ± s e (Ma) g a t U n e 235 r a p p Pb*/ A 207 ± (Ma) U* 238 Pb*/ 206 corr. error ± (%) U 238 Pb*/ 206 s ± o (%) i t a r e U* p o t 235 o s I Pb*/ 207 ± (%) Pb* 207 ) Pb*/ 206 TABLE 2. DATA USED TO CALCULATE U-Pb AGES OF DETRITAL ZIRCONS FROM PERMIAN AND MIOCENE ROCKS ( ZIRCONS FROM PERMIAN AGES OF DETRITAL U-Pb CALCULATE TO USED 2. DATA TABLE continued Pb U/Th 204 Pb/ 206 U 42.73 22175.06 1.39 5.30 1.05 12.74 1.15 0.49 0.47 0.41 2570.44 9.89 2660.89 10.84 2730.38 17.33 2730.38 17.33 94.1 31.0963.09 8973.8323.56 1.37 8383.77 1.62 4063.19 1.08 9.08 13.38 12.80 3.78 7.46 7.91 4.58 1.98 2.00 4.09 7.68 12.11 0.30 0.19 0.19 1.56 1.84 0.38 9.17 0.24 0.76 1700.05 1130.84 1098.32 23.30 19.05 92.63 1746.21 1107.44 1115.94 34.11 51.82 82.19 1801.92 1061.77 1150.43 68.82 150.20 157.33 1801.92 1130.84 68.82 1150.43 19.05 157.33 106.5 94.3 95.5 90.05 62042.09 0.9692.13 5.3771.61 2216.38 11634.47 2.34 3.35 0.47 11.70 13.15 13.33 4.17 6.4547.21 1.3150.88 8347.9993.02 2.29 0.52 24155.77 2.05 1.84 0.71 38948.36 0.80 1.22 4.22 12.49 0.93 6.52 5.79 2697.03 5.46 0.19 7.87 0.20 26.82 1.02 0.6540.26 2703.30 0.50 0.98 0.15 0.15 2.38 18986.03 12.33 12.28 1145.00 1.62 1150.60 12.86 6.83 8.03 10.27 2707.97 1.44 11.16 1209.33 1.05 1132.15 0.22 7.82 0.52 29.81 44.54 2.64 2707.97 0.51 1.57 1.02 0.20 1326.06 7.82 1096.96 0.70 0.92 3.08 1257.94 99.6 0.88 129.20 2680.97 80.69 17.99 2652.84 1096.96 22.32 1326.06 129.20 2.82 80.69 20.10 1236.21 104.9 2626.14 86.3 57.43 2669.57 0.25 13.56 9.92 1198.52 1.00 2584.14 0.35 155.39 2682.25 1435.32 17.10 1198.52 155.39 12.85 2584.14 105.0 8.32 17.10 1427.82 103.7 2682.25 21.62 8.32 98.9 1416.64 50.44 1416.64 50.44 101.3 37.83 13100.0091.95 2.87 10669.98 1.10 11.66 10.99 3.25 3.79 2.98 3.28 3.34 4.11 0.25 0.76 0.26 0.23 1447.01 1.59 0.39 9.86 1496.10 21.23 1401.75 25.37 1475.79 31.96 1333.56 1446.68 62.84 1333.56 72.13 62.84 1446.68 108.5 72.13 103.4 116.76 190.89 1.10 -1.37 475.29 -0.12 475.50 0.00 14.11 0.03 7.45 1.05 -125.21 -742.89 0.00 1387.57 7.45 1.05 118.44 37792.77 1.11 10.99 1.48 3.05119.38 33377.26 2.15 3.20 10.81 0.24 1.56 0.85 0.73 1404.17 19.68 3.09 1420.90 17.32 16.44 0.24 1446.04 17.30 1.00 28.18 1400.10 1446.04 217.85 28.18 1431.17 97.1 133.71 1477.65 16.15 1477.65 16.15 94.8 (ppm) 192.47160.36 333.29233.88 1.79409.08 265.67169.10 2.36 352.59 4.57187.26 1.48 762.45153.17 2.53 249.45 180.36 3.80 23.99 1.20 28.43124.97 14.40 267.36 2.47 99.42 176.24189.34 0.04 1.79 8.99 122.96 45.68 10.50 181.02133.98 1.52 398.97 116.08 0.05 3.75 0.01139.66 1.37 212.64802.67 0.00 0.02 176.61 263.03 120.61 99.70 1.42 0.02 2.15 282.63 0.41 15.39 1540.99 0.03 45.76 2.41 0.09 295.98 0.00 2.16 116.61 0.00 0.06 2064.55 1.80 213.83 11.45 0.00 1.94 122.42 31.75 8.12 0.06 7.44 0.00 0.11 310.90 0.07 0.41 0.00 377.02 2.74 1.25 11.14 296.11 42.45 0.00 0.06 2064.67 0.10 7.78 22.47 9.35 0.08 0.11 20.99 37.92 0.89 0.00 0.09 10.55 0.00 0.17 0.01 0.70 8.64 311.15 13.37 67.47 377.93 22.49 0.29 8.88 10.16 0.01 0.96 0.03 42.93 7.03 3.00 0.00 52.18 2972.01 2.13 0.00 12.37 15.80 12.37 50.75 7.68 20.67 574.06 0.00 7.38 0.04 27.30 26.23 0.07 7.17 23.86 57.30 -245.55 1.73 3267.20 0.66 57.66 6.35 8.12 0.15 6.93 68.31 1820.16 345.45 1.25 7.94 911.45 107.25 1532.35 0.00 0.86 … 10.08 310.74 3287.40 131.48 992.88 2.08 556.41 … 0.64 985.11 7.78 80.39 10.55 9.35 8.64 13.37 0.89 245.15 85.42 0.00 0.29 0.70 10.16 0.96 3.00 319.79 6.88 1317.96 2.13 4395.76 … 4289.05 1083.27 2.94 931.26 7.38 885.32 -1011.96 0.66 6.93 1309.60 7.68 0.86 7.94 1.73 2.08 10.08 0.64 173.29 14488.31355.82 1.44247.06 23528.25 116421.68 2.01 5.97 3.41202.03406.19 67307.29 9.05197.23 8.71 1.18 0.33 55511.62 0.64 72713.19 2.99 0.37 10.37 4.32 0.62380.67 5.95 43938.66 5.94104.01 4.34 2.21 3.92 0.73 5.22101.94 0.25 38550.88169.55 13.15 2.23 0.38 0.45 42409.21 1.42 17.24436.23 2.53 0.84 26333.38 10.55 12.85 1.64 2.18 96858.70 10.01 0.28 0.55 0.99 4.14 4.23 0.33 5.91 1.27 13.22 2390.45 1.37 4.05142.37 1.39 13.50 2.46 0.54 0.97 43.61 1.95209.27 0.97 0.45 0.45 48290.22 1615.19 1.57279.55 126202.40 2468.74 0.71 1836.15 4.07 0.43 2.17 9.87 0.80 19.58139.48 0.98 1.49 1.25 45637.32 39.24 20.45 11.27355.95 0.98 2.45 2785.91 1.34 68524.31 1700.64 1.89 5.93398.39 0.96 4.15 1855.30 6.93 0.98 2417.22 0.19 65804.84 92.11 1.68 2533.83 11.71 2.07 13.57 1.03 2310.54 70557.63 25.21 21.59 2.51 2948.36 3.04 0.48 1.39 0.20 26.07 6.21 1.35 0.93 1807.60 5.55 2.37 2484.02 0.48 39.72 1876.81 5.95 0.86 2435.50 1099.67 2533.83 0.91 0.18 11.83 7.11 0.22 8.99 0.97 2.02 0.16 6.72 5.55 14.04 12.87 7.42 3061.16 11.26 0.98 1187.71 1.30 1.95 1.73 2539.10 1807.60 94.3 1876.81 0.78 1098.62 2540.35 1.49 2.23 1.24 2541.59 11.71 11.26 6.72 9.91 0.94 9.89 2.27 1073.78 42.51 10.02 10.53 3061.16 97.8 4.14 2.30 89.4 19.33 1171.81 981.40 11.71 0.39 7.46 6.29 2545.60 2539.10 0.37 1.19 1096.54 20.29 28.88 91.0 2.54 1077.84 2541.59 0.17 4.14 19.34 1.15 1.82 0.92 1.99 6.29 16.66 1000.57 10.97 0.45 95.2 0.80 1142.53 2.13 0.45 2549.78 2106.82 90.9 1099.67 15.07 0.93 2042.62 1086.05 14.04 0.69 0.38 20.58 80.55 1016.02 2.18 0.58 31.87 100.3 0.86 1042.79 7.47 1142.53 20.05 2337.27 31.52 2374.47 1.32 80.55 2163.30 2415.56 2549.78 0.66 1073.78 13.73 104.0 16.16 11.34 1021.21 7.47 43.83 20.28 19.33 2098.99 14.82 2424.88 981.40 99.6 23.62 98.9 2545.04 2482.43 20.29 2279.86 10.97 23.52 2168.37 1032.35 94.1 7.99 23.25 17.83 2467.45 2537.62 17.44 2545.04 2279.86 23.25 1016.02 7.99 2234.68 16.34 21.85 20.05 89.6 82.8 2467.45 2537.62 98.4 25.83 16.34 21.85 2234.68 96.2 95.2 25.83 93.9 214.91134.01 39334.98235.19 105267.65 2.60 1.52304.35 63729.79301.86 198457.17 12.11 1.03 1.75273.33 5.78 3406.28 71109.63 9.85 2.43 1.08206.68 5.93 3.77 0.33 167429.99 1.42142.48 6.06 11.79 0.85 2.44 0.19 11.87 43233.60 5.89 2.82136.09 1.07 1.08 3.87 1.70 11.38 1.79 9.44 232.60 0.44 0.21 8.85 1.77 1.46 2.67 1.13 0.50 11.39 0.97 1.31 0.28 1.48 1.76 0.49 0.74 0.77 1.56 0.98 1249.71 0.67 1.56 655.21 2605.03 1.12 3.64 0.39 0.23 0.88 14.87 0.99 37.65 1573.27 2566.02 0.49 1253.19 1.02 1.12 4.01 0.22 2594.28 0.69 21.77 0.72 23.62 12.22 0.51 655.44 16.75 2116.17 1323.20 0.76 1606.94 2554.55 0.25 18.34 13.41 1259.18 2557.71 14.32 10.57 2585.88 0.00 3.89 2322.43 10.79 1318.91 0.97 21.12 17.12 1651.34 2545.44 13.48 11.50 5.55 0.03 1433.57 2555.94 1259.18 21.12 2585.88 50.00 15.72 2509.02 6.26 3.26 1311.94 99.2 5.55 7.74 1651.34 1558.16 2545.44 100.7 15.72 18.04 2554.52 20.96 1.32 31.95 3.26 95.3 2509.02 1311.94 100.8 18.04 20.96 205.80 1731.37 7.28 100.9 84.3 2554.52 17.88 … 7.28 1731.37 100.1 17.88 82.8 0.00 1324.87 7.74 1.32 1991.13 3218.11 1.381301.43 24.65 2909.70 1.57 14.65 21.94 0.01 27.21 15.00 0.01 0.00 27.23 3.23 0.22 0.00 10.38 1.01 0.04 0.33 14.47 9.11 0.15 1.36 14.24 -314.85 3.85 377.06 -24.94 10.38 669.59 0.33 14.47 0.15 JSR-09-5-006 JSR-09-5-007 AKR-09-3-067 JSR-09-5-013 JSR-09-5-017 JSR-09-5-018 JSR-09-5-020 JSR-09-5-033 JSR-09-5-037 JSR-09-5-053 JSR-09-5-062 JSR-09-5-075 JSR-09-5-076 JSR-09-5-081 JSR-09-5-086 JSR-09-5-092 JSR-09-5-004 AKR-09-3-039 AKR-09-3-040 AKR-09-3-043 AKR-09-3-044 AKR-09-3-045 AKR-09-3-048 AKR-09-3-050 AKR-09-3-052 AKR-09-3-053 AKR-09-3-054 AKR-09-3-055 AKR-09-3-057 AKR-09-3-058 AKR-09-3-060 AKR-09-3-064 AKR-09-3-065 AKR-09-3-066 AKR-09-3-068 AKR-09-3-072 AKR-09-3-074 AKR-09-3-081 AKR-09-3-082 AKR-09-3-083 AKR-09-3-086 AKR-09-3-087 AKR-09-3 (muscovite-rich sandstone) ( JSR-09-5-012 JSR-09-5-087 AKR-09-3-088 AKR-09-3-089 AKR-09-3-090 AKR-09-3-091 AKR-09-3-092 AKR-09-3-093 AKR-09-3-094 AKR-09-3-096 AKR-09-3-098 AKR-09-3-099 lacustrine deposit) JSR-09-5 (tuffaceous JSR-09-5-005 Sample number AKR-09-3-037

1452 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

It has more Archean zircon than the last two samples, with a large peak ca. 2600 Ma, similar in age to dated exposures of the Green Creek Complex (Strickland et al., 2011b). One zircon has a discordant Oligocene age (possibly derived from the Cassia plutonic complex) (%) Comments Conc and was not included in Figure 11. Based on

± the similarity of the stratigraphic position of (Ma) AKRR-09–3 and JSR-09–6 (Fig. 8), the young detrital zircon grains from these two samples

(Ma) were combined to calculate a weighted average Best age ) age of 10.5 ± 0.4 Ma, interpreted as the approxi-

± mate depositional age of unit 2 (Fig. 10A). (Ma) This sample also yielded 10 discordant zircon continued analyses and 14 additional analyses with high Pb* 206 238 207 235 207 Pb/ U or high Pb/ U errors, which have

Pb*/ apparent Miocene ages. The CL images of the 206 )

a detrital zircon grains with apparent Miocene M ( ages have similar textures to low-U zircon from ± s e (Ma) g epositional. Miocene volcanic rocks (cf. group 2 of Fig. 5D a t U

n with 5C). e 235 r

a Sample JSR-09–5 is a tuffaceous sandstone p p Pb*/

A from the middle of unit 3 (Table 1). Of 100 207 zircon grains analyzed, only 37 were concor-

± dant with acceptable errors and ages older (Ma) than 20 Ma, and were used to plot relative and U*

238 cumulative probability curves (Fig. 11). The relative probability diagram of this sample is Pb*/

206 similar to AKR-09–1A and JSR-09–6 in that it contains zircon populations ranging in age corr. error from Paleoproterozoic through Mesoprotero- ±

(%) zoic (2000–1000 Ma), with large peaks ca.

U 1600 Ma and 900 Ma (Figs. 11B, 11C). The 238 sample has a strong early Paleozoic age peak

Pb*/ (ca. 450 Ma), a few ca. 2450–2300 Ma zircon 206 grains, and one Archean (ca. 3050 Ma) zircon. s ± Two Eocene zircon grains (ca. 35 Ma) are o (%) i t a r ) discordant and were not included in the dia- e U* p gram. A population of 15 young detrital zircon o t 235 o

s grains with low errors was used to calculate a I Pb*/ continued weighted mean of 9.7 ± 0.7 Ma representing 207 the approximate depositional age for the upper

± part of unit 3 (Fig. 10A). Several zircon grains (%) were excluded from further statistical analy- 206 238 207 235

Pb* sis due to high Pb/ U or high Pb/ U

207 errors or because they were discordant. Of

Pb*/ the 54 excluded zircon grains, most (38) 206 yielded approximate Miocene ages with high TABLE 2. DATA USED TO CALCULATE U-Pb AGES OF DETRITAL ZIRCONS FROM PERMIAN AND MIOCENE ROCKS ( ZIRCONS FROM PERMIAN AGES OF DETRITAL U-Pb CALCULATE TO USED 2. DATA TABLE 206Pb/238U errors while 16 yielded discordant ages. CL imaging of the zircon grains from Pb U/Th

204 this sample indicate that several of the discor-

Pb/ dant zircon grains have large chaotic cores and 206 zoned rims, very similar to zircon dated from the Oligocene plutons of the core complex (cf. U 86.38 52684.53 1.73 3.42 2.1264.44 24.43 9914.0770.73 5.29 13298.60 2.47 2.63 12.9815.78 13.02 0.61 3387.17 4.98 5.0493.24 1.27 4.62 0.51 32012.94 13.09 2.03 0.70 3056.48 30.79 2.08 11.4542.09 5.16 9.30 3285.79 5808.71 5.09 24.10 1.85 1.65 0.19 1.14 0.20 3428.84 12.18 11.65 1.35 0.26 4.52 2.15 32.96 1128.75 0.18 0.42 4.49 3428.84 13.97 1156.72 2.64 32.96 2.14 22.75 0.18 1126.71 89.1 2.43 1041.16 0.30 35.15 1142.63 20.60 5.36 34.94 2.38 1122.81 0.90 1061.96 1714.00 1115.99 0.21 99.42 76.86 35.81 1122.81 92.22 2.92 99.42 1104.92 0.55 1733.97 100.5 1115.99 92.22 1255.06 229.58 21.92 103.6 33.34 1041.16 20.60 1758.14 1252.23 94.2 38.57 20.79 1758.14 1247.37 20.79 97.5 87.95 1247.37 87.95 100.6 111.60 6787.02 1.82 6.26 2.81 9.62 3.10 0.44 1.32 0.42 2337.71 25.80 2399.55 28.55 2452.45 47.55 2452.45 47.55 95.3 114.08 2541.37114.26 0.64 56294.27 1.32 17.12 9.17 14.13 0.67 0.61 19.13 4.59 0.08 1.35 12.89 0.67 0.31 467.52 1.16 58.13 0.87 1717.09 480.85 17.56 73.40 1747.54 544.94 11.22 310.25 1784.14 467.52 12.29 58.13 1784.14 85.8 12.29 96.2 114.18 30492.27 1.63 10.80112.35 0.69 34376.97 1.49 3.24 10.93 1.11 1.36 0.25 2.95 0.88 0.79 3.32 1458.44 11.43 0.23 1467.35 3.02 8.64 0.91 1353.05 1480.26 36.91 13.01 1393.59 1480.26 25.15 13.01 98.5 1456.18 25.94 1456.18 25.94 92.9 (ppm) 375.60 57562.68 4.07 12.55 1.32 1.88 1.74 0.17 1.13 0.65 1018.71 10.66 1074.38 11.50 1189.17 26.00 1189.17 26.00 85.7 287.64172.18 20104.71 0.81 51497.33488.90 0.92233.11 150422.64 10.18 7.35 118638.65 9.87 9.51424.41 1.70 117106.64 9.42 3.83 8.54 0.77 3.02 0.43 9.31 0.59 3.85 9.25 4.28 0.38 2.55 5.52 0.22 3.40 4.35 0.28 1.52 9.10 0.98 0.29 2.43 2.12 1297.18 0.34 0.95 106.89 3.38 1568.52 0.99 1.40 0.29 1412.60 33.88 0.92 1652.16 70.70 1895.46 2.08 49.22 1602.93 0.98 23.00 20.58 1688.70 1591.22 1657.72 1903.83 30.41 28.03 1648.44 31.80 13.08 1701.96 1591.22 1734.36 14.34 31.80 17.47 1912.96 1648.44 81.5 7.93 14.34 1756.86 10.66 1734.36 95.2 1912.96 7.93 10.66 7.04 95.3 99.1 1756.86 7.04 94.4 214.93163.27 75156.72 2.93 49478.99526.68 3.19126.71 51256.86 9.12452.74 1.02 41687.77 8.47219.27 3.43 71761.47104.94 1.61 0.46 35260.64 5.88 0.55 0.91 51693.63 9.90149.02 2.96 8.55 4.64 17.52 0.27 39165.07127.05 5.90 2.54 1.09 5.43 5.05 28833.09 1.44 10.48 3.84128.97 2.16 2.39 9.78 4.12 0.46 51798.21 0.31 4.36 1.58 12.18 3.19 0.62 0.36 0.88 1.68 13.21 1.36689.03 0.45 0.95 5.49 9.34 2.21 1.09 209888.62 3.89 0.92 1724.78 9.41 0.30302.51 4.01 1.08 1.56 1993.72 0.27 20.63121.19 0.99 0.93 0.08 25763.94 2.46 1.28 37.82102.90 8.84 1.54 2380.42 0.52 0.76 31234.58 2.45 1756.49 2.15 1.84 0.61 0.39 26361.04 30.97 1960.80 1669.81 12.01 0.16 4.94 1.89 16.03 2.21 0.98 1543.72 0.28 0.31 18.84 20.71 0.90 2478.02 10.72 492.47 29.51 1794.42 13.12 2698.25 0.22 2.27 14.64 1657.51 2.28 1.93 1926.22 2.89 0.93 21.56 1705.27 5.26 1.29 13.76 1.55 8.32 2559.04 1613.68 0.33 1.95 45.34 0.82 16.28 2694.57 492.75 0.94 1794.42 32.61 1641.93 1.96 1268.72 1926.22 10.21 2.98 2.07 15.18 8.32 1909.91 4.56 16.28 0.91 17.85 1636.34 1.87 103.5 20.31 2.73 96.1 2559.04 0.34 2691.79 14.74 1860.08 19.91 90.67 1261.18 494.07 1641.93 4.56 33.45 2.46 20.31 1909.91 1.94 0.11 13.67 93.0 0.23 0.99 101.7 1665.57 7.63 90.67 84.71 1808.82 1872.65 2691.79 1.92 0.18 80.8 14.69 1248.36 19.16 0.70 16.37 492.47 1.00 7.63 31.53 2.89 1665.57 1.50 1341.59 100.2 21.26 667.48 0.61 1750.24 16.37 1861.70 177.92 99.7 1248.36 12.18 1056.00 96.9 16.75 21.26 1401.37 17.01 14.62 101.6 112.50 672.13 1750.24 1849.48 17.01 1070.87 13.40 1493.49 106.3 16.26 5.52 687.76 24.42 1849.48 1101.26 1493.49 5.52 41.27 24.42 101.3 38.91 89.8 667.48 1056.00 12.18 14.62 97.1 95.9 155.69 21787.68282.59 1.21 71646.43 17.26 2.45 9.26 4.80group 0.50 0.61 3 of 3.91 4.96 Fig. 0.08 1.62 5E 1.25to 0.26 0.25 5A 475.44 1.54 0.95and 5.72 1502.48 5B) 20.59 484.43 (Strickland 1615.41 19.10 13.06 527.18 1765.86 105.23 9.09 475.44 1765.86 5.72 9.09 90.2 85.1 et al., 2011b). In addition, most of the zircon grains with high errors and apparent Miocene

Geochronologic analyses performed using the LA-ICP-MS as the University of Arizona Laserchron facilty. Conc—concordance; Depo—d Arizona Laserchron facilty. Geochronologic analyses performed using the LA-ICP-MS as University of ages have CL images similar to the low-U zircon from Miocene volcanic rocks (cf. group 2 Note: JSR-09-5-008 Sample number JSR-09-5-078 JSR-09-5-079 JSR-09-5-084 JSR-09-5-091 JSR-09-5-095 JSR-09-5 (tuffaceous lacustrine deposit) (muscovite-rich sandstone) ( JSR-09-5 (tuffaceous JSR-09-5-010 JSR-09-5-014 JSR-09-5-015 JSR-09-5-016 JSR-09-5-021 JSR-09-5-023 JSR-09-5-028 JSR-09-5-029 JSR-09-5-038 JSR-09-5-039 JSR-09-5-040 JSR-09-5-044 JSR-09-5-045 JSR-09-5-046 JSR-09-5-047 JSR-09-5-049 JSR-09-5-050 JSR-09-5-052 JSR-09-5-056 JSR-09-5-057 JSR-09-5-059 JSR-09-5-065 JSR-09-5-077 JSR-09-5-083 JSR-09-5-094 JSR-09-5-099 JSR-09-5-100 of Fig. 5E to 5C).

Geosphere, December 2012 1453

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al. ) e r o t t c r n n o a a d r r d d e continued r r t ( e i r o o h c c e rejection s s g reason for h i i i n Comments or I D D H (%) Error Pb 206 Pb 204 Pb/ corrected 207 8 9 1 3 8 9 1 2 9 1 1 7 6 7 0 8 9 9 0 6 2 7 2 7 3 8 8 9 2 7 8 3 3 9 6 3 ...... 7 9 3 9 9 7 7 0 2 3 5 3 7 8 4 5 8 3 (%) Error 1 1 1 1 1 1 1 1 2 Pb 5 5 4 5 6 8 5 5 5 7 6 6 6 5 0 4 6 7 206 0 0 0 0 1 0 0 0 0 0 0 0 0 3 2 0 0 7 ...... 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Total Pb/ 207 2 3 4 6 4 9 5 9 0 7 0 2 1 3 5 7 6 2 5 1 7 1 2 5 6 0 7 2 9 8 1 2 6 1 0 6 ...... (%) 1 2 2 2 1 1 1 2 3 2 2 2 2 3 2 3 2 1 Error Pb 6 2 5 0 0 2 2 8 7 1 3 3 5 9 0 1 8 1 5 2 3 4 4 0 6 3 6 9 4 6 2 2 5 7 5 7 ...... 206 ...... 2 5 1 5 8 0 2 2 9 2 6 7 3 1 7 5 0 6 Total U/ 3 78.63 0.41 0.05 1.79 0.05 4.03 Inherited core 6 7 5 8 9 7 5 7 7 8 7 5 7 6 9 8 4 6 6 645.07 2.05 0.05 4.68 0.05 5.55 690.27 1.18 0.05 5.59 0.05 5.59 6 6 715.17 2.16 0.04 11.71 0.06 15.49 683.28 1.46 0.04 7.76 0.08 22.84 686.52 3.03 0.07 11.59 0.07 11.59 678.60 1.51 0.05 8.29 0.05 8.29 657.02686.21 3.74 0.86 0.06 0.05 4.26 4.02 0.04 0.01 21.94 92.24 5 6 6 677.50682.70693.23 2.17 1.93 1.22 0.03 0.03 0.05 14.38 12.25 5.54 0.06 0.06 0.03 34.41 32.65 35.00 6 613.36723.15 2.25 1.62 0.05 0.06 5.76 7.60 0.07 0.06 20.15 7.60 Discordant Discordant 645.69 2.15 0.07 20.72 0.09 18.14 684.30 1.90 0.07 11.95 0.11 20.21 720.50 1.65 0.06 7.23 0.06 7.23 Discordant 671.91 0.96 0.04 5.02 0.05 10.65 6 725.04 1.40 0.07 26.00 0.07 25.70 Discordant 7 4 3 4 764.11 1.03 0.05 4.73 0.02 78.97 Discordant 7 468.77 3.024 0.05 17.35 0.15 31.68 2 4 655.97 0.66 0.05 3.09 0.03 26.07 High U 582.09 2.38 0.07 21.05 0.05 37.04 High U 238 ) σ (1 error Absolute U 238 Pb 9.66 0.21 9.96 0.21 9.33 0.11 9.64 0.27 9.76 0.22 9.03 0.20 9.09 0.29 9.38 0.08 9.47 0.14 9.329.37 0.15 0.44 9.45 0.15 9.58 0.16 9.50 0.22 9.60 0.36 9.65 0.22 9.629.24 0.19 0.12 9.68 0.28 8.80 0.15 9.14 0.20 8.83 0.15 9.65 0.10 9.43 0.27 8.65 0.23 8.20 0.27 8.39 0.09 8.36 0.19 9.79 0.07 age 207 Pb/ 10.15 0.16 81.32 0.35 10.44 0.24 13.27 0.43 13.59 0.55 13.48 0.39 13.55 0.48 13.36 0.52 13.37 0.45 13.70 0.44 12.61 5.79 10.69 0.33 corrected 206 ) σ (1 Error U 238 Pb age 204 Pb/ corrected 206 TABLE 3. DATA USED TO CALCULATE U-Pb AGES OF MIOCENE IGNEOUS ROCKS U-Pb CALCULATE TO USED 3. DATA TABLE U 238 Th/ 232 Th (ppm) U (ppm) Pb (%) 206 Common JS11-31 0.29 278.7 165.2 0.61 9.80 0.26 JS11-24CJS11-19C 0.17 3.35 470.1 2475.9 195.7 906.7 0.43 0.38 81.17 10.77 0.37 0.29 JS11-27JS11-29JS11-30 0.02 0.25 0.20 465.9 630.3 334.6 150.3 547.1 0.74 68.6 0.90 0.47 9.33 10.02 7.85 0.11 0.21 0.79 JS11-26 –0.42 85.8 46.6 0.56 8.47 0.55 JS11-23 0.68 136.4 76.0 0.58 8.53 0.56 JS11-25 –0.29 148.3 80.3 0.56 9.14 0.21 JS11-22 –0.46 306.3 168.7 0.57 9.93 0.28 JS11-16B 3.09 75.1 33.7 0.46 9.38 0.28 JS11-15 3.84 141.2 73.9 0.54 7.17 1.38 JS11-16AJS11-17JS11-20R 2.04 2174.3 0.07 1079 14.38 928.1 0.51 336.3 756.4 188.3 0.84 9.59 0.58 0.37 9.03 8.95 0.16 0.53 JS11-18C 0.17 256.1 132.2 0.53 8.86 0.27 JS11-21C 0.45 249.2 136.5 0.57 9.49 0.14 JS11-14 –0.05 230.3 114.5 0.51 9.07 0.26 JS11-12JS11-13 –1.95 0.53 170.0 423.8 91.0 213.7 0.55 0.52 9.77 9.08 0.30 0.16 JS11-11 –1.45 133.8 65.1 0.50 9.81 0.33 JS-11B-6AJS-12.1 0.63 1.21 330.5 210.4 289.1 0.66 146.5 0.52 10.79 8.91 0.31 0.14 JS-11B-3 2.95 187.7 112.9 0.62 10.20 0.24 JS11-9 2.94 183.3 90.3 0.51 9.90 0.33 JS-11B-5 1.27 249.7 119.3 0.49 8.94 0.15 JS-11B-4 2.60 320.2 246.3 0.80 8.89 0.13 JS11-8 –0.63 701.8 594.3 0.87 9.72 0.11 JS-11B.1 1.70 89.3 44.3 0.51 5.45 1.04 AKJS-09-11 (lower rhyolite lava) AKJS-09-11 JS11-6B 0.44 80.9 44.5 0.57 8.24 0.74 AKR-09-2-7 2.37 127.5 85.6 0.69 9.71 1.73 AKR-09-2-4 37.95 256.0 151.4 0.61 10.74 2.08 AKR-09-2-2AKR-09-2-3 0.86 2.12 117.9 168.2 62.2 96.6 0.55 0.59 12.90 9.25 0.68 1.59 AKR-09-2-5 2.13 98.3 44.7 0.47 10.02 1.57 JS11-7 0.44 627.9 364.9 0.60 8.11 0.15 JS11-10 2.26 140.5 119.4 0.88 7.55 0.41 AKR-09-2-6 20.03 123.1 72.5 0.61 12.86 1.57 AKR-09-02 (ash-fall tuff) AKR-09-02 (ash-fall tuff) AKR-09-2-1 –0.45 122.9 65.3 0.55 15.16 1.07 JS11-18R 91.86 133.2 86.4 0.67 14.42 7.40 Spot name JS11-28 0.30 1537.3 966.0 0.65 9.61 0.11

1454 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex t r n o a r r d r e o h c rejection s g reason for i i Comments or D H (%) Error Pb 206 Pb 204 Pb/ corrected 207 5 5 4 7 6 9 8 0 6 7 2 1 1 2 7 7 4 6 3 2 5 3 8 8 5 2 2 0 ...... 3 0 3 2 6 6 8 3 6 0 5 7 7 9 (%) Error 1 2 2 1 3 1 1 1 1 1 1 1 ) Pb 6 5 6 7 2 5 5 8 6 7 4 5 5 6 206 0 0 0 0 2 0 0 0 0 0 4 0 0 0 ...... 0 0 0 0 0 0 0 0 0 0 0 0 0 0 continued Total Pb/ 207 . Numbers in italics indicate analyses excluded from any calculation due 6 0 2 3 7 2 2 2 6 8 5 7 3 3 6 8 4 6 4 0 4 3 9 4 7 2 2 7 ...... (%) 2 3 4 2 3 3 3 2 3 2 2 1 3 3 Error Pb 9 7 0 8 7 4 0 0 1 5 5 9 9 1 8 9 5 5 0 5 1 1 8 2 8 1 5 8 ...... 206 ...... 0 1 0 0 5 1 8 8 5 4 4 1 0 0 Total 1 U/ 6 7 5 6 9 6 8 9 3 8 9 8 6 8 7 750.98 1.62 0.06 11.79 0.03 39.13 797.43776.42 3.63 2.68 0.05 0.06 20.76 13.63 0.05 0.06 20.76 13.63 7 831.29 3.35 0.07 15.84 0.07 15.84 802.04 2.64 0.07 14.22 0.10 32.38 627.37 2.40 0.05 12.92 0.05 12.92 Discordant 7 584.27 0.76 0.06 3.74 0.03 35.28 High U 4 304.52 2.40 0.54 4.40 0.19 95.19 High error 753.03 3.54 0.04 22.12 0.04 22.12 Pb loss 591.72 1.50 0.05 8.67 0.03 40.33 Inherited core 6 697.12 3.68 0.06 18.33 0.06 18.33 6 689.87 1.56 0.05 8.71 0.05 8.71 689.58 1.50 0.05 8.49 0.05 8.49 697.70 3.26 0.05 18.95 0.05 18.95 6 6 653.75 2.17 0.06 11.25 0.06 11.25 845.63 3.82 0.05 28.03 0.14 41.32 6 3 6 793.71 4.07 0.03 35.44 0.24 29.46 769.70752.81 2.47 4.19 0.05 0.07 13.83 20.07 0.05 0.07 13.83 20.07 6 717.35 3.11 0.05 18.27 0.05 18.27 7 663.02 2.64 0.05 13.99 0.05 13.99 379.67 3.26 0.38 9.83 0.23 58.01 779.90 1.06 0.05 5.84 0.05 5.84 238 ) σ (1 error Absolute U 238 Pb 8.46 0.16 8.36 0.24 7.80 0.37 8.33 0.33 8.078.18 0.31 0.23 7.82 0.23 7.54 0.27 8.37 0.24 8.03 0.67 8.65 0.32 9.089.30 0.36 0.30 9.57 0.35 9.32 0.15 9.20 0.33 9.33 0.15 9.148.90 0.32 0.29 9.72 0.23 8.98 0.24 9.68 0.65 7.61 0.32 9.40 0.13 8.35 0.38 8.99 0.29 8.35 0.22 9.43 0.32 9.65 0.27 8.28 0.35 9.83 0.86 8.248.31 0.09 0.33 age 207 Pb/ 10.21 0.26 10.83 0.09 10.79 1.46 10.89 0.17 corrected 206 ) σ (1 Error U 238 Pb age 204 Pb/ corrected 206 U TABLE 3. DATA USED TO CALCULATE U-Pb AGES OF MIOCENE IGNEOUS ROCKS ( U-Pb CALCULATE TO USED 3. DATA TABLE 238 Th/ 232 Th (ppm) U (ppm) Pb (%) 206 Common Geochronologic analyses performed using the SHRIMP-RG. Numbers in bold indicate values used to calculate weighted mean age Note: C1B-4.1 1.25 172.0 144.3 0.87 7.11 0.61 C1B-5.1 1.69 65.7 37.2 0.59 5.10 1.23 C1B-13.1 0.28 1181.4 1856 1.62 8.26 0.09 C1B-9.1C1B-10.1C1B-11.1 0.12 1.45 1.38 95.1 179.6 479.7 166.8 66.6 374.6 0.96 0.72 0.81 8.30 8.08 8.33 0.22 0.29 0.18 C1B-3.1 2.60 185.7 156.8 0.87 8.38 0.40 C1B-8.1 0.34 82.7 50.7 0.63 6.53 0.96 AKC-09-1B (upper rhyolite lava) C1B-2.1 2.78 121.5 96.7 0.82 7.75 0.26 JS1-7.1 0.54 166.8 101.3 0.63 10.27 0.25 JS1-16.1JS1-18.1 1.75 2.46 1434.3 1024 178.9 156.8 0.74 0.91 10.60 7.47 0.15 0.52 JS1-9.1 62.04 94.0 59.6 0.65 9.88 2.56 JS1-14.1 –1.13 90.1 52.0 0.60 8.55 0.30 JS1-16.2 22.10 113.6 80.9 0.74 11.53 1.48 JS1-14.2 –0.06 420.2 267.1 0.66 10.62 0.20 JS1-2.1JS1-20.1 1.73 0.20 82.2 128.5 41.6 86.9 0.52 0.70 9.24 8.50 0.34 0.46 JS1-19.1 0.73 90.4 51.1 0.58 7.34 1.23 JS1-15.1JS1-17.1 0.14 0.16 454.1 441.4 267.3 260.3 0.61 0.61 9.34 9.34 0.14 0.15 C1B-18.1C1B-7.1C1B-1.1 0.06 6.57 0.81 93.5 1952.3 1309 56.5 99.9 0.63 0.69 83.6 0.87 1954.21 8.59 3.72 7.21 0.73 1844.94 0.33 4.65 7.15 2.82 0.34 0.20 893.80 0.17 4.54 0.73 0.05 0.17 18.86 0.05 0.83 High U 18.86 Discordant JS1-12.1 1.72 90.6 46.7 0.53 7.92 0.67 C1B-12.1C1B-6.1 0.68 –0.37 183.2 301.7 77.0 207.1 0.43 0.71 1512.86 9.47 8.14 1504.24 0.21 9.37 9.00 0.20 3.78 690.35 0.60 2.00 0.10 0.04 1.16 12.94 0.10 0.05 1.18 18.28 Discordant Discordant to the reason stated in “Comments” column. JS1-11.1JS1-13.1 1.06 3.89 111.3 68.1 125.9 0.63 89.2 0.73 9.23 6.83 0.30 1.12 JS1-10.1 1.31 238.9 138.8 0.60 9.85 0.21 JS1-8.1 3.27 178.1 85.3 0.50 7.35 0.90 JS1-6.1 0.56 776.1 547.7 0.73 8.98 0.21 JS1-7.2 49.67 76.3 43.2 0.58 8.74 2.84 C1B-16.1 0.24 200.3 137.8 0.71 8.37 0.21 JS1-4.1 0.36 109.7 79.7 0.75 8.21 0.67 JS1-3.1JS1-5.1 0.65 –0.13 162.1 140.7 124.4 0.90 95.5 0.79 9.72 8.98 0.26 0.28 C1B-17.1 2.43 68.5 42.1 0.64 8.56 0.36 C1B-15.1 –1.96 84.4 49.5 0.61 11.01 1.34 AKJS-09-1 (Lower rhyolite lava) JS1-1.1 42.04 70.9 36.7 0.53 12.87 2.58 C1B-14.1 1.87 86.3 51.9 0.62 6.82 0.75 Spot name

Geosphere, December 2012 1455

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

To test for similarity between the detrital zir- (Fig. 11). This observation is compatible with rhyolites unconformably overlie metamorphic con populations of sedimentary rocks of the Salt the fairly large P-values obtained by performing rocks along the west fl ank of the Albion Moun- Lake Formation to the older rocks of the Penn- the K-S test (P = 0.09–0.51; Fig. 11D; Gehrels tains (Armstrong et al., 1975; Compton, 1972, sylvanian–Permian Oquirrh Group (Figs. 11B, et al., 2006). The P-values in the K-S test from 1975; Miller et al., 2008). 11C), detrital zircons were analyzed from two detrital zircon suites test the null hypothesis The general absence of Middle Eocene age Pennsylvanian–Permian samples. Sample DC-1 that any two randomly selected detrital zircon (55–45 Ma) zircon populations in the Miocene is a calcareous sandstone from the Lower Penn- populations are not similar. High P-values dis- sediments of the Raft River Basin indicate that sylvanian–Permian Oquirrh Group near Dove prove the null hypothesis, thus the two popula- the ca. 52–45 Ma Challis volcanic fi eld located Creek Pass (Fig. 11), and has zircon age populations in question can be interpreted to be similar. north of the ARG and the Snake River Plain tions that range from Paleoproterozoic through The high P-values and the apparent similarity (Fig. 1) (Janecke and Snee 1993; Dostal et a., Mesoproterozoic (2000–1000 Ma), with large in detrital zircon populations between the late 2003; Gaschnig et al., 2010) was not a major peaks at 1750, 1650, and 1500 Ma (Fig. 11B). Paleozoic rocks and the Miocene strata lead us source of detritus as the Raft River Basin devel- The sample has an early Paleozoic zircon popu- to infer that late Paleozoic strata were the domi- oped. Given the widespread exposure of the lation (ca. 450 Ma) and several Archean through nant detritus source for the earliest part of the Challis volcanic rocks and the fact that zircon Paleoproterozoic (ca. 3050–2450 Ma) zircon Miocene Raft River Basin. This inference is crystals from this region were transported as far grains. Sample PER-SS is an Early Permian compatible with and supported by abundant late west as the coast of California (Dumitru et al., sample from the northern Black Pine Mountains Paleozoic clasts in the basal Miocene conglom- 2013), we postulate that a physiographic bar- (northern block of Smith, 1982; Figs. 8 and erates of unit 1, and by the observed relationship rier, possibly a Miocene age Snake River Plain 11B; Table 2). This sample is a fi ne-grained, that across this region mostly Pennsylvanian– thermal bulge (e.g., Anders and Sleep 1992), or silty limestone with very small (<50 μm) zircon Permian strata were exposed at the Cenozoic a valley like the present-day Snake River Val- grains. The detrital zircon population of PER-SS erosional surface (Fig. 4B). The other major ley, may have restricted sediment transport from is almost identical to that of DC-1 with a large sources of detrital zircon for the Salt Lake For- north to south during the development of the Paleoproterozoic to Mesoproterozoic zircon mation were Miocene ash-fall tuffs, ignimbrites, Raft River Basin in the Miocene. The absence suite ranging in age from 2000 to 1000 Ma, sev- and volcanic fl ows that were deposited proximal of Challis-age zircon in the basin is also indirect eral early Paleozoic (ca. 450 Ma) zircon grains, to the region (Figs. 5D, 5E). evidence in favor of the lack of development of and several Archean to Paleoproterozoic (ca. A notable exception to the nearly identical Eocene–Oligocene catchments or basins in the 3050–2450 Ma) zircon grains. detrital zircon populations of the Miocene and region of the ARG. These earlier basins, if they the late Paleozoic samples is the sandstone sam- existed, would likely have contained sediments Zircon U-Pb SHRIMP-RG Analyses of the ple AKR-09–3 from unit 2 (Fig. 10). This sample with 52–45 Ma zircon that would in turn have Jim Sage Volcanic Suite contains a larger percentage of Neoarchean (ca. been reworked into the younger Miocene basins. 2600 Ma) zircon (Figs. 11B, 11C), indicat- The three Miocene volcanic rocks collected ing that rocks from the Green Creek Complex Slip History of the Albion Fault and Raft from the Jim Sage and Cotterel Mountains (Fig. may have been exposed and eroding at that time River Detachment 8A; Tables 1 and 3), dated using SHRIMP-RG, (ca. 10.5 Ma). Sample JSR-09–5 also contains provide constraints on the end of the deposition several zircon grains having CL images that The Albion fault, which strikes north-south in of unit 3 and the onset of magmatism related to are characterized by chaotic (metamict) cores map view and dips ~20°–30° to the east (Figs. 8 the Snake River Plain, in the Raft River Basin. with magmatic overgrowths, and that look very and 9), most likely represents the fault that fi rst The 207Pb-corrected 206Pb/238U ages of suites similar to zircon dated from the Cassia plutonic moved ca. 14 Ma to create the accommodation of zircon grains were used to calculate the complex (Strickland et al., 2011b; cf. group 3 of space that was then fi lled by Miocene sediments weighted mean age for each sample. The lower Fig. 5E to Figs. 5A, 5B). Both of these obser- of the Salt Lake Formation. The fault mapped rhyolite (unit 4) has an age of 9.46 ± 0.09 Ma vations indicate that the deep metamorphic and as the Raft River detachment (Figs. 8 and 9) (2σ; MSWD = 1.5; n = 23) at its base and 9.33 ± plutonic rocks of the ARG core complex were possibly represents an exhumed ductile-brittle 0.10 Ma (2σ; MSWD = 0.86; n = 16) for the top at the surface and exposed to erosion by ca. transition zone into which the Albion fault par- of the unit (Figs. 5 and 10A); the two reported 10.5 Ma, consistent with the fact that Miocene tially rooted. The faults mapped within the south ages for unit 4 are within error of each other. A (ca. 9 Ma) volcanic rocks are mapped as uncon- part of the Raft River Basin displace rocks as sample from the top part of unit 6 results in a formably overlying Archean basement rocks in young as ca. 9.5 Ma and have displacements weighted average age of 8.21 ± 0.15 Ma (2σ; the core of the Albion Mountains and Miocene ranging from ~500 m to ~2.5 km (Fig. 8; cross- MSWD = 1.4; n = 14). These three ages are interpreted to represent the eruptive ages of unit 4 and unit 6. Figure 11 (on following page). (A) Generalized stratigraphy of Proterozoic–Miocene sedi- Sources for the Salt Lake Formation mentary rocks of the Albion–Raft River–Grouse Creek metamorphic core complex and surrounding region (modifi ed from Compton, 1983; Wells, 1997). The stratigraphic positions A comparison of the detrital zircon popula- of samples analyzed for detrital zircon geochronology are shown. (B) Relative probability tions from the Miocene Salt Lake Formation diagram of analyses that yielded <20% discordant ages. (C) Cumulative probability dia- to those from late Paleozoic sediments shows gram of analyses that yielded <20% discordant ages. (D) The P-values obtained from the a striking similarity (Figs. 11B, 11C). The zir- K-S (Kolmogorov-Smirnov) test for the six samples. Values higher than 0.05 are highlighted con age peaks and approximate percentage of in blue and disprove the hypothesis that the two samples are dissimilar, while samples in each age population in the Miocene rocks are light red have P-values less than 0.05 and confi rm the hypothesis that the samples are dis- very similar to those from late Paleozoic strata similar. See text for discussion.

1456 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex D C 0.461 0.508 0.955 0.654 0.024 0.001 0.047 0.246 0.024 AKR-09-3 0.001 AKR-09-3 basement? plate (~2550 Ma) Weathering lower Weathering 0.092 0.991 0.246 0.654 0.144 0.308 0.207 0.991 0.047 0.955 Age (Ma) 0.308 0.207 0.508 0.974 JSR-09-5 AKR-09-3 JSR-09-6 AKR-09-1A PER-SS DC-1 0.974 0.144 0.092 0.001 0.001 0.461 PER-SS DC-1 AKR-09-1A JSR-09-6 JSR-09-5 DC-1 PER-SS JSR-09-5 AKR-09-3 JSR-09-6 AKR-09-1A 0 500 1000 1500 2000 2500 3000 3500 4000

1.0 0.8 0.6 0.4 0.2 0.0 Cumulative Probability Cumulative JSR-09-5 n = 37 AKR-09-3 n = 67 JSR-09-6 n = 55 AKR-09-1A n = 55 DC1 n = 83 PER-SS n = 83 Figure 11. Figure 2500 2000 Age (Ma) 1500 1000 500 3500 4000

120 Ma

0 3000 Relative Probability Relative collected Collected at PER-SS DC-1 Metasiltstone Dolomite Quartzite Calcarenite and limestone Schist and quartzite Orthogneiss and Schist AB from Northern Black Pine Mountains) Tuff, sandstone Tuff, marls and mudstones Cross bedded sandstone Breccia and conglomerate Unconformity (Sample Interbedded Calcareous silty sandstone and sandy limestone (Sample Raft Dove Creek Pass in W. River Mountains) Limestone and sandstone Sandy dolomitic limestone Sandy-silty dolomitic limestone Calcareous cross-bedded sandstone 0 m 0 m 250 Eureka complex 1000 Gerster Fm. Green Creek Thaynes Fm. Unnamed unit Chainman Fm. Oquirrh Group Salt Lake Fm. Unnamed unit Garden City Fm. Diamond Pk. Fm. A M O Age Formation name U. P L. P M. P

Geosphere, December 2012 1457

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

section B–B′). The faults cut and repeat the 0 Miocene sedimentary sequence and appear to W Grouse Creek and Albion Mts. Raft River Mts. E die southward, minimally (<500 m) displacing Stage 3: Rapid cooling, the mapped trace of the Raft River detachment faulting, syn-extensional (Figs. 8 and 9). We interpret these crosscutting 5 sedimentation and volcanism relationships to indicate that the normal faults mapped in the Raft River Basin are younger than both the Albion fault and the high-strain 10 fabrics of the Raft River detachment. The east-west trend of the trace of the Raft River detachment separating lower plate rocks 15 beneath the domed detachment from upper Mean AFT Age = 13.4±1 Ma ApparentApparent Gap:Gap: plate Miocene fault blocks can be interpreted (From Egger et al., 2003) ~ 1122 MaMa as a having a major strike-slip component in its early history of slip between 13.5 and 9.5 Ma. 20 Distance (km) East of Western front of Albion Mountains An alternative interpretation is that the normal 0 10 2030 40 50 faults that cut and rotate the Miocene basinal Cooling of Oligocene plutons and metamorphic rocks sequence sole into a basal detachment beneath 25 the Raft River Valley, and this fault system Red Butte pluton has been cut and downdropped by a down- Stage 2: Crustal melting, remobilization and diapiric rise of granitoids,

Age (Ma) accompanied by extreme thinning of cover rocks to-the north normal fault along the northern Vipoint pluton (and southern) fl anks of the Raft River Moun- 30 Almo pluton tains, uplifting the Raft River Mountains with Middle Mnt gneiss respect to the faulted Miocene basin sections and exposing the basal detachment fault, which 35 Emmigrant Pass plutonic complex might have formed the Miocene ductile-brittle transition zone (Figs. 8 and 9). While these two Stage 1: Precursor magmatism. scenarios are not mutually exclusive, we pre- fer the former scenario, given that the lower 40 Early Nanny Creek volcanism. plate rocks at the north edge of the Raft River Mountains have north-dipping foliation planes but east-west–trending lineations, thus preclud- 45 ing ductile top-to-the-north stretching, which Key would produce north-south–oriented lineations. Another piece of evidence precluding much Apatite fission track cooling ages with Ages of volcanic rocks from 2σ error bars (Egger et al., 2003) top-to-the-north motion along the northern Jim Sage and Cotterel Mountains (this study) edge of the Raft River Mountains is the fact that Apatite fission track cooling ages with the dips of the Miocene strata do not change 2σ error bars (Wells et al., 2000) Timing constrains for normal toward the Raft River detachment, which might faulting based on develop- be expected if the northern edge of the Raft Zircon U-Pb ages of plutons within the ment of syn-extensional basin ARG (Egger et al., 2003; Strickland et (this study) River detachment had top-to-the-north motion al., 2011b) (Fig. 9). Regardless of the exact kinematic relationships, the entire evolution of the complex Figure 12. Diagram summarizing the geochronological, thermochronological, and tectonic resulted in the domal nature of the elongate events in the Albion–Raft River–Grouse Creek (ARG) metamorphic core complex. AFT— Raft River Mountains core complex, which apatite fi ssion track. See text for relevant discussion. appears to wrap around the northern, southern, and eastern edges of the mountain (Fig. 9). Apatite and zircon fi ssion track ages from the Raft River Mountains (Wells et al., 2000) and detailed history of the Miocene faulting and almost exclusively from upper plate Paleozoic the Albion Mountains (Egger et al., 2003) range deposition temporally related to the 13.4–7 Ma rocks (Figs. 11B, 11C, 13A, and 13B). from 15.1 ± 2.4 to 7.4 ± 2.0 Ma (2σ), and were low-temperature uplift and cooling history of By between ca. 10.5 and 9.5 Ma, sediment interpreted to represent cooling via the rapid adjacent footwall rocks. sources to the basin included structurally deeper exhumation of the footwall to near surface con- The oldest Miocene tuff dated (13.45 Ma) rocks of the footwall (Archean and Cenozoic ditions ca. 13.4 Ma (Egger et al., 2003; Fig. 12; records the beginning of deposition of the Salt intrusive rocks) with continued contribution of summary of apatite fi ssion track thermochronol- Lake Formation in the Raft River Basin. Fault- debris from the hanging wall (Paleozoic), con- ogy) and to record the progressive unroofi ng of ing along the Albion fault began ca. 14 Ma, with sistent with a history of rapid exhumation docu- the Raft River detachment during the migration rapid slip occurring between 13.5 and 10.5 Ma mented by the reverse clast stratigraphy (Fig. of a rolling hinge from ca. 13.4 to 7 Ma (Wells (Figs. 12, 13A, and 13B). During this time, the 10D) and detrital zircon signatures of basin et al., 2000; Wells, 2001). The new data from the basin developed its greatest accommodation sedi ments (Figs. 11A, 11B, and 13C). Rapid slip Raft River Basin allow us to delineate a more space and was fi lled with clastic detritus derived on the Albion fault was responsible for the rise

1458 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

Future A-RR fault system ~14 Ma A Figure 13. Diagram summarizing the Mio- N cene exhumation of the Albion–Raft River– Penn-Perm strata A-RR Grouse Creek (ARG) metamorphic core at surface E W complex based on the evolution of the Raft Pz Oligocene River synextensional basin. Abbreviations: fabrics Penn-Perm—Pennsylvanian–Permian, Ductile-Brittle transition zone AF—Albion fault, RRD—Raft River detach- P ~5 km ment, AF-RRD—Albion fault–Raft River Almo pluton at depth detachment system, P—Archean–Protero- 13.5–10.5 Ma zoic strata, Pz—Phanerozoic strata, Ts— Raft River Basin Miocene Salt Lake Formation, Tv—Miocene B N A-RR volcanics. (A) The onset of high-angle faulting is ca. 14 Ma, predating the onset of deposition in the basin and synchronous with the E Ts Pz W earliest evidence for cooling of footwall rocks Pz P Oligocene through the apatite fi ssion track annealing fabrics temperature. Previously developed Oligo- cene granite-cored gneiss domes shown at ~5 km depth of ~10 km. (B) Between 13.5 and 10.5, Almo pluton rapid slip on the Albion fault exhumes (and 10.5–9.5 Ma A cools) the metamorphic and igneous rocks of RRD the complex, creating accommodation space C N Raft River Basin for the deposition of units 1 and 2 of the Raft AF River Basin. (C) Between 10.5 and 9.5 Ma, the P large topographic depression that formed in E Tv W the previous period (13.5–10.5 Ma) is fi lled Ts Pz Miocene Oligocene with ash-fall tuffs and rhyolite, while the fabrics fabrics sedimentary sequence is probably rotated by Crustal flow ~10°. (D) After ca. 9.5 Ma, the basin-fi ll depos- ~5 km its and overlying volcanic rocks are dissected Miocene pluton Almo pluton by an array of normal faults. The footwall of 9.5–7.0 Ma Differential uplift of Raft River Mts. the core complex rotates to shallow angles, Albion Mts. causing the intrabasin faults and the sedimen- D Raft River Mts. RRD tary section to rotate by as much as ~30°–40°. At the same time the Raft River Mountains N Black Pine Mts. AF P undergo relative uplift (doming) with respect Raft River to the faulted sedimentary sequence. The Basin Tv E W locus of extension migrates eastward through Oligocene Pz Ts time doming the Raft River Detachment, fabrics until ca. 7 Ma, when major extension ceases. P ~5 km Younger faults Crustal flow Miocene pluton Almo pluton

of the Albion Mountains and fi nal exposure at After ca. 9.5 Ma, extension was accommo- amount (current dip 48°W; red symbols in Figs. the surface of deep crystalline basement, as evi- dated by a series of intrabasin planar normal 9 and 10C). denced by unconformities preserved in parts of faults that cut, rotate, and repeat the Miocene Drill core data indicate that the younger than the Albion Mountains, where ca. 9 Ma volcanic sequence, including the volcanic rocks (Figs. 3, 8.2 Ma unit 7 (upper tuffaceous member of Wil- rocks (Armstrong et al., 1975) overlie meta- 8, 9, and 13D). Extension after ca. 9.5 Ma was liams et al., 1982) was deposited mostly the morphic and igneous rocks. The topographic also responsible for the rotation of the intrabasin eastern Raft River Basin (Williams et al., 1974, depression formed between 13.5 and 10.5 Ma normal faults to shallower angles. This inter- 1982) and that faulting and sedimentation pro- by motion on the Albion fault was quickly fi lled pretation is supported by the dips of bedding gressively stepped eastward toward the center by ash-fall tuffs and rhyolite fl ows. The rotation in units 1–3 which, where mapped, are about of the basin. of the Albion fault and the basin fi ll deposits the same independent of stratigraphic position, The depositional and faulting history of the (by ~5°–15°) appears to have occurred during suggesting that most rotation occurred after Raft River Basin indicates that the Albion fault this time span, as indicated by the small angu- the deposition of unit 3 (Fig. 10C). This rela- likely initiated at a fairly steep angle (~60°) and lar unconformity developed between unit 3 and tion is best observed in fault block 4, where an accommodated a minimum of 4 km of vertical unit 4 (Fig. 13C). ~2.5-km-thick section is rotated by the same component of slip based on the thickness of units

Geosphere, December 2012 1459

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

1–3 (2500 m) and the present-day relief from the this metamorphic core complex and its bound- mediate to felsic igneous rocks intruded as both basin to Cache Peak, Idaho (~1400 m). We infer ing detachment faults did not develop during a shallow-level plutons (the Emigrant Pass plu- that this fault system may have been the same single protracted event, as suggested by many tonic complex) and erupted volcanic sequences as the plane of initial slip along what is now models, but rather, its evolution took place in a (Figs. 12 and 14) (e.g., Compton, 1983; Kistler the Raft River detachment (Fig. 13). We envi- series of steps or stages (Figs. 12 and 14). and Lee, 1989; Brooks et al., 1995; Nutt and sion that the entire Albion fault system began Ludington, 2003; Egger et al., 2003). This to move ca. 14 Ma, rotated by 5°–15° between Stage 0: Preextensional Deformation early magmatism was driven by mantle-derived 14 and 9.5 Ma, and likely soled into a shallow magmas, which interacted and assimilated sig- ductile-brittle transition zone, which was later Regional studies of Mesozoic deformation nifi cant amounts of crust beneath this region exhumed and is now the Raft River detachment. in the Sevier belt east of the ARG indicate that (Fig. 14), resulting in hybrid magmas (Grunder Thus, in our interpretation the mylonite shear shortening was partitioned in time between 145 1993, 1995; Gans et al., 1989; Humphreys et al., zone of the Raft River detachment represents and ca. 55 Ma, along four major thrust systems 2003; Dostal et al., 2003). Despite the evidence the boundary between a plastic and/or viscous (e.g., Armstrong, 1963; DeCelles, 1994; Burt- for voluminous magmatic activity (as well as lower plate and its elastic lid (upper plate). Most ner and Nigrini, 1994; DeCelles, 2004; Yonkee hybridization at depth) and the possibility that of the rotation of the Miocene section and its and Weil, 2011). These studies document that signifi cant weakening of the crust might have bounding faults occurred after ca. 9.5 Ma; this the motion on these thrust systems migrated occurred during this time span, there is limited is based on the fact that all Cenozoic sedimen- eastward through time mostly in the Meso- evidence for large offset high-angle faults and tary units older than 9.5 Ma are involved in the zoic, with minor shortening continuing into the signifi cant basin development in the ARG and same amount of rotation during faulting. There- Cenozoic (Wiltschko and Dorr, 1983; Heller surrounding region. Specifi cally, the regional fore most of the fl exural rotation to shallower et al., 1986; DeCelles, 1994, 2004; Burtner and Cenozoic unconformity map (Fig. 4) suggests angles of the intrabasin fault blocks, the Albion Nigrini; 1994; Yonkee and Weil, 2011; Appen- that only late Paleozoic strata were exposed at fault and the Raft River detachment, occurred dix 1). Geochronologic and thermochronologic the surface before Cenozoic magmatism began. after ca. 9.5 Ma. During this time, rocks beneath studies of the deeper parts of the stratigraphic However, we acknowledge that using the ero- the present-day exposures fl owed in the ductile section exposed in the ARG suggest that this sional surface presented in Figure 4 as a datum regime and underwent stretching (Fig. 13D). part of the hinterland of the Sevier thrust belt results in a somewhat crude estimate of the The minimum amount of Miocene extension was subject to burial and metamorphism in the amount of exhumation prior to the Cenozoic, can be calculated by cross-sectional line-length Mesozoic (e.g., Hoisch et al., 2002, 2008; Harris especially in the region of the ARG where the balancing of the Cenozoic unconformity across et al., 2007; Wells et al., 2012) but the crustal Pennsylvanian and Permian strata are as much the region north of the Raft River Mountains thickness at the end of Mesozoic shortening is as 7–8 km thick. Thus multiple high-angle nor- (Fig. 8; cross-section B–B′). The present-day not well quantifi ed and is somewhat controver- mal faults may have developed across the top east-west width of the exposure of the uncon- sial (e.g., Coney and Harms, 1984; Gans et al., of the ARG as long as they only cut and off-

formity is ~38 km (Dﬁ nal) and the cross-sec- 1989; DeCelles, 2004; Colgan and Henry 2009; set Pennsylvanian–Permian strata and did not tional length of the unconformity, after the Ernst, 2010). Our beginning diagram (Fig. 14) bound deep basins.

restoration of fault slip, is 22 km (Doriginal). The shows a crustal thickness of ~45–50 km, similar calculated β-factor from these estimates is 1.72 to estimates from east-central Nevada based on Stage 2: Diapiric Ascent of Pluton-Cored and the minimum amount of Miocene exten- the palinspastic restoration of Cenozoic exten- Gneiss Domes, 32–25 Ma sion is ~72%. sional structures (Gans et al., 1989). Following the shallow-level emplacement DISCUSSION Stage 1: Precursor Eocene Magmatism, and eruption of magmas between 42 and 42–34 Ma 34 Ma, heating likely continued at depth, lead- The geochronologic, thermochronologic, and ing to broader melting and ultimately mobili- structural data from the ARG discussed herein Following Mesozoic–early Cenozoic crustal zation of the deeper crust. We envision that the (summarized in Fig. 12) reveal a complex and thickening, calc-alkaline magmatism migrated maturation of the MASH zone established dur- protracted Cenozoic extensional history for this from southern Canada to southern Nevada ing stage 1 resulted in the episodic production complex. The various Cenozoic events affecting between ca. 55 and ca. 20 Ma (Armstrong and of crustal melts that became the plutonic cores this region differ in terms of their timing and the Ward, 1991; Best and Christiansen 1991; Chris- of Oligocene crustal welts (gneiss domes), crustal processes they represent, but each event tiansen and Yeats, 1992; Gans et al., 1989). The which rose diapirically to depths of ~10–15 km sets the stage for subsequent events. Resolv- southward sweep of magmatism is attributed to under extensional boundary conditions (Fig. ing and understanding this history is crucial to asthenospheric upwelling following the delami- 14). The diapiric rise of these welts to the answering many of the puzzling questions about nation of the shallowly dipping Farallon slab, base of the upper crust was accompanied by the timing of events in metamorphic core com- which led to the intrusion of maﬁ c magmas extreme thinning and stretching of roof rocks plexes and the nature of detachment faults that into the crust (e.g., Armstrong and Ward, 1991; at amphibolite (sillimanite) facies, forming bound them. Best and Christiansen, 1991; Christiansen and the well-developed foliation and extensional The most important conclusion of the data Yeats, 1992; Humphreys 1995; Humphreys lineation dated by U-Pb monazite and zircon presented here is that the extreme attenuation of et al., 2003; Fig. 1), resulting in widespread as 32–25 Ma (Egger et al., 2003; Strickland, units at amphibolite (sillimanite) facies in the heating and melting of the lower and middle 2010; Strickland et al., 2011a, 2011b; Fig. 14). ARG developed at least 10 m.y. prior to the ﬁ nal crust, forming large MASH zones (mixing- This mobile infrastructure was separated from exhumation of the metamorphic core complex assimilation-storage-hybridization; Fig. 14). the overlying brittle crust by detachment faults, during Basin and Range faulting. This docu- In the region of the ARG, this event is rep- such as the Ingham Pass fault and the high- mented difference in timing makes it clear that resented by ca. 42–34 Ma calc-alkaline inter- temperature portion of the Middle Mountain

1460 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

Stage 1: Precursor magmatism (42–34 Ma)

Material and thermal input from the mantle leads to lower crustal melting and Shallow magma chambers hybridization. Lower crustal MASH zone of dacitic composition gives rise to shallow (5–10 km) plutons of intermediate-felsic composition.

Formation of lower crustal MASH zone

Partial melting of lower crust

MOHO 10 km Basaltic flux into lower crust

Up to 22 km extension Stage 2: Diapiric rise of granites and Localized normal metamorphic country rocks (32–25 Ma) faulting extreme ductile thinning Expansion of lower crustal MASH zone High-T shear zone of country rocks results in diapiric rise of granitoids to 10–15 Collapsed km depth, accompanied by extreme thinning biot in isograds Expansion of sill in of cover rocks. Thermal weakening of crust MASH zone results in lower crustal flow, flattening the MOHO and the surface topography. DBTZ Flow Flow

10 km MOHO evens out Waning basaltic flux

High-T rhyolite Rotational fault Stage 3: Basin and Range rapid extension and basalt blocks and exhumation of core complex (14–7 Ma)

Onset of rapid extension and rotation of fault Miocene blocks during the Miocene, with formation of basins syn-extensional basins filled by intercalated sediments and high-T rhyolites and basalts. Continued flow of lower crust weakened by Miocene magmatism. Extensional strain accommodated across broad regions in the upper crust resulting in Basin and Range faulting and topography. MOHO Mantle Basaltic flux to Figure 14. Summary of a proposed tectonic model for the lithosphere the crust formation of the Albion–Raft River–Grouse Creek (ARG) 10 km Melting at metamorphic core complex. MASH—mixing-assimilation- plume head Asthenosphere storage-hybridization; DBTZ—ductile-brittle transition zone; T—temperature. See text for discussion.

Geosphere, December 2012 1461

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

shear zone (Egger et al., 2003; Strickland et al., cut and offset the 13.5–10.5 Ma sediments and (stage 2), because they are separated by a sub- 2011a, 2011b). These high-temperature shear 10–8 Ma volcanic rocks. Rapid slip on both the stantial time gap of 10–12 m.y. This observa- zones were diachronously developed, but rep- early parts of the Albion fault as well as along tion is signifi cant because it implies that not resent the result of the development of a pro- the faults that cut the Salt Lake Formation cor- all fabrics and mylonites in metamorphic core tracted ductile-brittle transition in the crust (or respond in age to the low-temperature cooling complexes formed at the same time or via the top of channel fl ow) (Fig. 14). history of footwall rocks that began at 14 Ma same process , and thus should not be kinemati- There is no evidence for volcanism during and progressed to after 7.5 Ma (Fig. 12; Wells cally linked in the interpretation of metamorphic the 32–25 Ma time interval of gneiss dome et al., 2000; Egger et al., 2003). core complexes. This study highlights that core development or for the formation of deep fault- During Basin and Range faulting, hotspot- complexes of the Basin and Range may have bounded sedimentary basins. It is possible that generated magmatism progressed eastward polygenetic and multiphase Cenozoic exten- supracrustal extension was extreme but took along the Snake River Plain–Yellowstone trend sional histories that need be accounted for when place only across the width of the crustal dia- (e.g., Draper, 1991; Pierce and Morgan, 1992; modeling their histories and determining the pirs, thus representing only about ~22 km of Ellis et al., 2010). The overlap in age between total offset and amount of extension they rep- localized extension across the ARG (Fig. 14). the nearest eruptive centers of the Snake River resent (Fig. 2). Normal faults that may have moved during this Plain (the 10.5–8.5 Ma Twin Falls and the ACKNOWLEDGMENTS time interval were subsequently deformed and 10.2–9.2 Ma Picabo centers) and the Miocene uplifted during the rise of the gneiss domes. extension in the ARG metamorphic core com- This work was made possible through grants Flow of more mobile lower to mid-crustal rocks plex (Figs. 10, 13, and 14) has important impli- awarded to Alexandros Konstantinou and Elizabeth into the regions of plutonism and crustal thin- cations for the evolution of the complex. This Miller. Field work funds were provided by a Leven- tis Foundation grant, a Stanford Graduate Fellowship, ning is likely (e.g., Gans, 1987; McKenzie et al., magmatism represents a major thermal event and a Stanford McGee Fund awarded to Alexandros 2000), thus the region of the ARG metamorphic that may have resulted in crustal heating and Konstantinou. Field and analytical work were funded core complex might have been a site of uplift melting, thus decreasing the strength of the crust by National Science Foundation Tectonics Division and erosion rather than deposition. One of the and assisting younger and deeper crustal fl ow grants EAR-0809226 and EAR-0948679 to Miller. We thank Michael Wells, Mike Williams, and an important hallmarks of the geology of the ARG during Basin and Range extension and uplift of anonymous reviewer for comments that helped to sig- metamorphic core complex, recognized for the ARG metamorphic core complex. nifi cantly improve this manuscript. many years, is that ductile extensional fabrics related to vertical thinning are superimposed on CONCLUSIONS APPENDIX 1. TIMING OF SHORTENING AND LIST OF REFERENCES a complexly faulted Paleozoic section (Comp- ton et al., 1977; Miller, 1978, 1983; Wells, 1997; This study provides new structural and geo- Table A1 summarizes the timing of shortening Wells et al., 1998, 2000). This rather unusual chronologic data regarding the timing of sedi- recorded in the different thrust fault systems of the superposition of ductile fabrics on earlier brittle mentation, extensional faulting, and exhumation Mesozoic–early Cenozoic Sevier and Laramide orogenies in the northeastern Utah and Wyoming regions. structures may provide support for this specula- of the Albion–Raft River–Grouse Creek meta- Also shown is the list of references used in this study tive interpretation. morphic core complex. Coupled with existing to summarize the timing of shortening. geochronologic data that bracket the age of Stage 3: Basin and Range Faulting, lower plate magmatism, metamorphism, and APPENDIX 2. GEOCHRONOLOGY METHODS 14 to After 7 Ma diapiric rise of pluton-cored crustal welts, we A large split of detrital zircon grains is incorporated are able to distinguish three different stages into a 1 in (2.54 cm) epoxy mount together with frag- A 10–12 m.y. hiatus separated the diapiric leading to the development and exhumation of ments of our Sri Lanka standard zircon. The mounts rise of Oligocene plutons and their entrained this core complex that involved changing litho- are sanded down to a depth of ~20 µm, polished, imaged, and cleaned prior to isotopic analysis. wall rocks from the onset of Basin and Range spheric-scale processes (Fig. 14). U-Pb geochronology of zircon grains is conducted faulting. The timing of faulting along the Albion Deciphering this history has illustrated that by laser ablation–multicollector–inductively coupled and Raft River fault systems is recorded by the the faults that exhume the complex (stage 3) plasma mass spectrometry (LA-MC-ICPMS) at the inception of deposition into the Raft River Basin are a distinctly younger (and unrelated) event Arizona LaserChron Center (Gehrels et al., 2006, 2008). The analyses involve ablation of zircon with ca. 14 Ma (Figs. 10, 12, 13, and 14), synchro- than the amphibolite (sillimanite) grade fab- a New Wave UP193HE Excimer laser using a spot nous with the development of Miocene basins rics associated with the diapiric rise of the diameter of 30 µm. The ablated material is carried in south of the Raft River Mountains and along granite-cored gneiss domes in the Oligocene helium into the plasma source of a Nu HR ICPMS, the western fl anks of the Grouse Creek Moun- tains (Compton, 1983; Todd, 1980; Martinez, 2000, 2001; Egger et al., 2003). Specifi cally, the TABLE A1. TIMING OF INFERRED MOTION ALONG THRUST FAULT SYSTEMS OF Grouse Creek Basin developed in the hanging THE SEVIER-LARAMIDE OROGENY, AND CITATIONS FOR EACH SYSTEM wall of a Miocene fault system that cuts older Time of shortening Name of thrust fault system (Ma) References Oligocene fabrics and the Ingham Pass detach- Paris-Willard 145–90 Yonkee et al. (1989); Wiltschko and Dorr (1983); Burtner ment in the Grouse Creek Mountains (Fig. 7). and Nigrini (1994); DeCelles (1994, 2004); Yonkee and The high-temperature Middle Mountain shear Weil (2011) Meade-Crawford 95–84, 6–62 Wiltschko and Dorr (1983); Burtner and Nigrini (1994); zone is also cut by the same fault system to the DeCelles (1994); Yonkee and Weil (2011) north (Figs. 3 and 6). Rapid uplift of the ARG Absaroka 83–60 Wiltschko and Dorr (1983); Heller et al. (1986); Burtner and metamorphic core complex occurred between Nigrini (1994); DeCelles (1994, 2004); Yonkee and Weil (2011) ca. 14–10.5 Ma, by faulting on both sides of the Hogsback-Darby, merges 64–52 Wiltschko and Dorr (1983); DeCelles (1994, 2004); Yonkee complex. After ca. 8 Ma, extension was accom- with Prospect thrust and Weil (2011) modated by systems of intrabasinal faults that (eastern Wyoming)

1462 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

which is equipped with a fl ight tube of suffi cient width con population signatures and that the similarities ~1.2 km thick exposure of unit 3 crops out on the that U, Th, and Pb isotopes are measured simultane- can be explained by a random distribution of detrital southeast fl ank of Jim Sage Mountains, previously ously. All measurements are made in static mode, zircon age. In contrast, a P-value >0.05 indicates that interpreted as part of the upper tuffaceous member using Faraday detectors with 3 × 1011 ohm resis- the samples may be similar in terms of their detrital (Williams et al., 1982). However, the sedimentary tors for 238U, 232Th, 208Pb-206Pb, and discrete dynode zircon population (Gehrels et al., 2008) and similari- rocks mapped in this outcrop do not contain rhyolite ion counters for 204Pb and 202Hg. Ion yields are ~0.8 ties between samples cannot be explained by random clasts and are more highly tilted than the overlying mv/ppm. Each analysis consists of 1 15 s integration distribution. rhyolite fl ows. The sedimentary strata consistently on peaks with the laser off (for backgrounds), 15 1 s dip ~32° to the east (blue symbols in Fig. 10C), while integrations with the laser fi ring, and a 30 s delay to APPENDIX 4. DETAILED STRATIGRAPHY the rhyolite fl ows dip at most ~18° to the east. Fur- purge the previous sample and prepare for the next OF THE SALT LAKE FORMATION thermore, the contact of the sedimentary rocks with analysis. The ablation pit is ~15 µm in depth. the rhyolite fl ows indicates that the volcanic rocks For each analysis, the errors in determining 206Pb/238U Unit 1, best exposed in fault blocks 2 and 4, is fl owed on top of, and disrupted, the sedimentary and 206Pb/204Pb result in a measurement error of ~1%– ~700 m thick and composed primarily of breccias, rocks. These observations indicate that the exposure 2% (at 2σ level) in the 206Pb/238U age. The errors in fanglomerates, and pebble conglomerates deposited of sedimentary rocks strata here is in fact older than measurement of 206Pb/207Pb and 206Pb/204Pb also result on top of the Pennsylvanian–Permian Oquirrh Group the rhyolites, and that its lithology is consistent with in ~1%–2% (at 2σ level) uncertainty in age for grains (Figs. 3, 8, and 10). The lower part of unit 1 is com- that of unit 3. In general, the lacustrine deposits con- that are older than 1.0 Ga, but are substantially larger posed of clast-supported, poorly sorted breccias and tain intercalated beds (to several tens of meters thick) for younger grains due to low intensity of the 207Pb fanglomerates derived primarily from the underly- of (unit 3-a) greenish-weathering, well-sorted ash- signal. For most analyses, the crossover in precision of ing Paleozoic limestone sequence. The upper part of fall tuffs with abundant glass shards and evidence 206Pb/238U and 206Pb/207Pb ages occurs ca. 1.0 Ga. unit 1 is composed of both clast and matrix-supported of soft-sediment deformation; (unit 3-b) off-white, The 204Hg interference with 204Pb is accounted for pebble conglomerate intercalated with coarse sand- well-sorted and sometimes cross-bedded calcarenite, measurement of 202Hg during laser ablation and sub- stone. Rare imbrications in the pebble conglomerate composed of subrounded grains of quartz and calcite; traction of 204Hg according to the natural 202Hg/204Hg indicate that the paleocurrent directions were pre- (unit 3-c) yellow to buff weathering cross-bedded, of 4.35. This Hg is correction is not signifi cant for domi nantly from the west to the east. fl uvial calcarenites with quartz and calcite sand (unit most analyses because our Hg backgrounds are low Clast counts of conglomerate indicate that the 3-d), fi ne-grained, thinly laminated chalks and marls (generally ~150 cps at mass 204). basal part of unit 1 are composed mostly of 3–15-cm- composed of smectite, and fi ne calcite with abundant Common Pb correction is accomplished by using diameter, subangular clasts of gray-blue carbonates pyrite, occasional gypsum, and bedding surfaces that the Hg-corrected 204Pb and assuming an initial Pb (inferred to be clasts of the Pennsylvanian–Permian exhibit abundant mud cracks (Fig. 10). The presence composition from Stacey and Kramers (1975). Uncer- Oquirrh Group) with lesser amounts of 2–5-cm-diam- of gypsum and mud cracks indicates the existence of tainties of 1.5 for 206Pb/204Pb and 0.3 for 207Pb/204Pb eter angular, white, massive quartzite clasts, similar to shallow ephemeral playa lakes in the Raft River Basin are applied to these compositional values based on the Ordovician Eureka Quartzite (Fig. 10D). Upsec- during that time. the variation in Pb isotopic composition in modern tion the quartzite clasts increase in abundance, while The base of unit 4 is a dark weathering, incipiently crystal rocks. small (1–2 cm in diameter) dark gray, mica-bearing to moderately welded ignimbrite, exposed ~7–8 km Interelement fractionation of Pb/U is generally carbonate clasts (inferred as clasts of the Fish Haven west of the Narrows, that contains pheno crysts of ~5%, whereas apparent fractionation of Pb isotopes Dolomite) are also present, together with inferred plagioclase, clinopyroxene, and Fe-Ti oxides. Strati- is generally <0.2%. In-run analysis of fragments of clasts from the Oquirrh Group (Fig. 10D). The upper graphically above, but never in direct contact with the a large zircon crystal (generally every fi fth measure- parts of unit 1 contain signifi cant amounts of 1–4-cm- ignimbrite is a thick sequence (~450 m) of massive, ment) with known age of 563.5 ± 3.2 Ma (2σ error) is diameter subangular clasts of mica-bearing meta- glassy rhyolitic lava fl ows with occasional columnar used to correct for this fractionation. The uncertainty morphosed calc-silicate rock, inferred to be clasts of jointing. The phenocrysts of these lavas consist of resulting from the calibration correction is generally the metamorphosed part of the Ordovician Pogonip plagioclase (andesine), augite, and pigeonite (Figs. 1%–2% (2σ) for both 206Pb/207Pb and 206Pb/238U ages. Group and the Proterozoic Schist of Mahogany Peaks 10A, 10E). Concentrations of U and Th are calibrated relative (Fig. 10D). Thus, the stratigraphy of unit 1 records Unit 5 is a lacustrine sedimentary unit, composed to our Sri Lanka zircon, which contains ~518 ppm of an unroofi ng sequence, where the oldest rock clasts of thickly bedded calcarenite and tuff, with thin beds U and 68 ppm Th. become progressively more abundant upsection (Fig. of volcanic sandstone composed of glass shards and The analytical data are reported in Table 3. Uncer- 110D). No granitic clasts were identifi ed (e.g., clasts lava fl ows or breccias containing clasts derived from tainties shown in the tables are at the 1σ level, and derived from sources that include the Almo pluton or underlying unit 4 (Figs. 10A, 10E). include only measurement errors. Analyses that are the Archean basement); therefore footwall igneous The bottom part of unit 6 is in sharp contact with >20% discordant (by comparison of 206Pb/238U and rocks were not exposed at the surface during the early unit 5, and is a massive rhyolite lava fl ow and locally 206Pb/207Pb ages) or >5% reverse discordant are not phases of motion on the basin-bounding fault (ca. an autobrecciated ignimbrite with abundant pepper- considered further. 13.5 Ma; this study). ites, which provide evidence that the lavas and the The resulting interpreted ages are shown on Pb*/U Unit 1 grades abruptly upward into red to buff col- ignimbrite fl owed in water or wet sediment. The rest concordia diagrams and relative age-probability dia- ored, coarse, occasionally cross-bedded sandstones of unit 6 is made up of ~450 m of intercalated mas- grams using the routines in Isoplot (Ludwig, 2003). of unit 2. The sandstones are composed primarily of sive, glassy, lava fl ows, thinly bedded lavas, densely The age-probability diagrams show each age and its moderately angular quartz, lithic fragments, feldspar, welded ignimbrites, and columnar-jointed rhyolite uncertainty (for measurement error only) as a normal and abundant muscovite (Fig. 10), and are interbed- fl ows (Figs. 10A, 10E). These rocks contain plagio- distribution, and sum all ages from a sample into a sin- ded with matrix-supported pebble conglomerates with clase (andesine), augite, pigeonite, and minor quartz gle curve. Composite age probability plots are made well-rounded 1–2 cm clasts of carbonate, quartzite, phenocrysts. The top of unit 6 is a capping sequence of from an in-house Excel program that normalizes each and schist. Collectively, the sandstones and conglom- basaltic fl ows (basalt of northern Cotterel Mountains curve according to the number of constituent analyses, erates of unit 2 are interpreted as fl uvial deposits. The of Williams et al., 1982), to ~100 m thick, exposed such that each curve contains the same area, and then abundant detrital muscovite in the sandstone, as well in the northern Cotterel Mountains (Figs. 3 and 10) stacks the probability curves. as the quartzite and schist clasts in the pebble con- and dated as 9.2 ± 1.5 (1σ) Ma (K-Ar; Armstrong glomerate, indicate mixed sources for unit 2, which et al., 1975, recalculated as 9.25 ± 1.5 Ma with new APPENDIX 3. STATISTICAL is interpreted to have been derived from detritus of decay constants; but the standard used in their study CALCULATIONS Paleozoic carbonates and quartzites as well as meta- was not reported). The volcanic rocks of units 4 and morphosed Proterozoic strata. Granitic clasts derived 6 are coeval with, and have phenocryst assemblages The K-S statistic is a statistical calculation takes from the Almo pluton or from the Green Creek Com- similar to, volcanic rocks of the central Snake River into account the squared differences of the cumula- plex were not observed in unit 2. Plain (e.g., Perkins and Nash, 2002; Ellis et al., 2010). tive probability curves between any two samples and Unit 2 grades upward into unit 3, which has a We interpret these rhyolites to represent the south- tests the hypothesis that two samples are different maximum thickness of ~1200 m and is largely com- ern extent of the Miocene magmatic province of the from each other and are therefore not obtained from posed of lacustrine deposits (lower tuffaceous mem- Snake River Plain (Konstantinou, 2011). the same parent population. A P-value <0.05 confi rms ber of Williams et al., 1982). This unit is best exposed Unit 7 is very poorly exposed along the fl anks of the hypothesis and indicates that the two samples are and described in fault blocks 2, 3, and 4 north of the the Cotterel and Black Pine Mountains (Figs. 3 and 8), statistically not similar in terms of their detrital zir- Raft River Mountains (Fig. 9). A nearly continuous and is mostly composed of thickly bedded reworked

Geosphere, December 2012 1463

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

tuffs that include clasts of rhyolite from units 4–6. Brooks, W.E., Thorman, C.H., and Snee, L.W., 1995, The Utah: Geological Society of America Bulletin, v. 88, Where unit 7 is exposed on the western fl ank of the 40Ar/39Ar ages and tectonic setting of the middle p. 1237–1250, doi:10.1130/0016-7606(1977)88<1237: Black Pine Mountains, it is composed of intercalated Eocene northeast Nevada volcanic fi eld: Journal of OAMMFA>2.0.CO;2. conglomerate containing angular clasts of the Oquirrh Geophysical Research, v. 100, no. B6, p. 10403–10416, Coney, P.J., 1980, Cordilleran metamorphic core complexes: doi:10.1029/94JB03389. An overview, in Crittenden, M.D., Jr., et al., eds., Group, and medium- to coarse-grained sandstone Buck, W.R., 1988, Flexural rotation of normal faults: Tecton- Cordilleran metamorphic core complexes: Geological (Smith, 1982; Wells, 2009). The sedimentary strata ics, v. 7, p. 959–973, doi:10.1029/TC007i005p00959. Society of America Memoir 153, p. 7–31. are tilted and dip as much as 30° to the east (Fig. 8). Burchfi el, B.C., Cowan, D.S., and Davis, G.A., 1992, Tec- Coney, P.J., and Harms, T.A., 1984, Cordilleran metamorphic Their tilts toward the range front, as well as the brecci- tonic overview of the Cordilleran orogen in the west- core complexes; Cenozoic extensional relics of Mesozoic ated nature of the contact with the Oquirrh Group, led ern United States, in Burchfi el, B.C., et al., eds., The compression: Geology, v. 12, p. 550–554, doi:10.1130 us to reinterpret the contact as a west-dipping normal Cordilleran orogen: Conterminous U.S.: Boulder, /0091-7613(1984)12<550:CMCCCE>2.0.CO;2. fault. Even though the exposures of unit 7 west of the Colorado, Geological Society of America, Geology of Covington, H.R., 1977a, Deep drilling data Raft River geother- Black Pine Mountains are lithologically similar to the North America, v. G-3, p. 407–480. mal area, Idaho: Raft River geothermal exploration well Burtner, R.L., and Nigrini, A., 1994, Thermochronology of #1: U.S. Geological Survey Open-File Report 77–226. description of unit 1 (this study), their age is likely the Idaho-Wyoming thrust belt during the Sevier orog- Covington, H.R., 1977b, Deep drilling data Raft River geother- younger than 9 Ma, because rhyolites similar to the eny; A new, calibrated, multiprocess thermal model: mal area, Idaho: Raft River geothermal exploration well 9.5–8.2 Ma Jim Sage volcanic rocks are described American Association of Petroleum Geologists Bul- #2: U.S. Geological Survey Open-File Report 77–243. in the nearby Strevell borehole. When these volcanic letin, v. 78, p. 1586–1612. Covington, H.R., 1977c, Deep drilling data Raft River geother- rocks are projected to the surface, they appear to Burton, B.R., 1997, Structural geology and emplacement mal area, Idaho: Raft River geothermal exploration well underlie the conglomerates adjacent to the Black Pine history of the Harrison Pass pluton, central Ruby #3: U.S. Geological Survey Open-File Report 77–616. Mountains, thus making the conglomerates equivalent Mountains, Nevada [Ph.D. thesis]: Laramie, University Covington, H.R., 1978, Deep drilling data Raft River geother- in age to unit 7 of this study (Fig. 8). of Wyoming, 590 p. mal area, Idaho: Raft River geothermal exploration well Catchings, R.D., 1992, A relation among geology, tecton- #4: U.S. Geological Survey Open-File Report 78–91. ics, and velocity structure, western to central Nevada Covington, H.R., 1979a, Deep drilling data Raft River geo- REFERENCES CITED Basin and Range: Geological Society of America thermal area, Idaho: Raft River geothermal exploration Bulletin , v. 104, p. 1178–1192, doi:10.1130/0016-7606 well #5 sidetrack B: U.S. Geological Survey Open-File Anders, M.H., and Sleep, N.H., 1992, Magmatism and exten- (1992)104<1178:ARAGTA>2.3.CO;2. Report 79–382. sion: The thermal and mechanical effects of the Yellow- Catchings, R.D., and Mooney, W.D., 1991, Basin and Range Covington, H.R., 1979b, Deep drilling data Raft River geo- stone hotspot: Journal of Geophysical Research, v. 97, crustal and upper mantle structure, northwest to cen- thermal area, Idaho: Raft River geothermal exploration no. B11, p. 15379–15393, doi:10.1029/92JB01376. tral Nevada: Journal of Geophysical Research, v. 96, well #4 sidetrack B: U.S. Geological Survey Open-File Armstrong, R.L., 1963, Geochronology and geology of the p. 6247–6267, doi:10.1029/91JB00194. Report 79–662. Eastern Great Basin in Nevada and Utah [Ph.D. thesis]: Christiansen, E.H., and McCurry, M., 2008, Contrasting ori- Covington, H.R., 1983, Structural evolution of the Raft New Haven, Connecticut, Yale University, 404 p. gins of Cenozoic silicic volcanic rocks from the western River Basin, Idaho; Tectonic and stratigraphic studies Armstrong, R.L., 1968a, Mantled gneiss domes in the Albion cordillera of the United States: Bulletin of Volcanology, in the eastern Great Basin, in Miller, D.M., et al., eds., range, southern Idaho: Geological Society of America v. 70, p. 251–267, doi:10.1007/s00445-007-0138-1. Tectonic and stratigraphic studies in the eastern Great Bulletin, v. 79, p. 1295–1314, doi:10.1130/0016-7606 Christiansen, R.L., and Yeats, R.S., 1992, Post-Laramide Basin: Geological Society of America Memoir 157, (1968)79[1295:MGDITA]2.0.CO;2. geology of the U.S. Cordilleran region, in Burchfi el, p. 229–237. Armstrong, R.L., 1968b, Pre-Tertiary stratigraphy of the B.C., et al., eds., The Cordilleran orogen: Conterminous Davis, G.H., Constenius, K.N., Dickinson, W.R., Rodrí- Albion Range, southern Idaho, in Abstracts for 1966: U.S.: Boulder, Colorado, Geological Society of Amer- guez, E.P., and Cox, L.J., 2004, Fault and fault-rock Geological Society of America Special Paper 101, ica, Geology of North America, v. G-3, p. 261–406. characteristics associated with Cenozoic extension and p. 384–385. Clark, T.M., Ehman, K.D., and Axelrod, D.I., 1985, Late core-complex evolution in the Catalina-Rincon region, Armstrong, R.L., 1982, Cordilleran metamorphic core Eocene extensional faulting in the northern Basin and southeastern Arizona: Geological Society of America complexes; from Arizona to southern Canada: Annual Range province, Elko County, Nevada: Geological Bulletin, v. 116, p. 128–141, doi:10.1130/B25260.1. Review of Earth and Planetary Sciences, v. 10, p. 129– Society of America Abstracts with Programs, v. 17, DeCelles, P.G., 1994, Late Cretaceous-Paleocene syn- 154, doi:10.1146/annurev.ea.10.050182.001021. no. 6, p. 348. orogenic sedimentation and kinematic history of the Armstrong, R.L., and Hills, F.A., 1967, Rubidium-strontium Colgan, J.P., and Henry, C.D., 2009, Rapid middle Miocene Sevier thrust belt, northeast Utah and southwest Wyo- and potassium-argon geochronologic studies of mantled collapse of the Mesozoic orogenic plateau in north- ming: Geological Society of America Bulletin, v. 106, gneiss domes, Albion Range, southern Idaho, U.S.A: central Nevada: International Geology Review, v. 51, p. 32–56, doi:10.1130/0016-7606(1994)106<0032: Earth and Planetary Science Letters, v. 3, p. 114–124, p. 920–961, doi:10.1080/00206810903056731. LCPSSA>2.3.CO;2. doi:10.1016/0012-821X(67)90021-0. Colgan, J.P., and Metcalf, J.R., 2006, Apatite fi ssion-track DeCelles, P.G., 2004, Late Jurassic to Eocene evolution of Armstrong, R.L., and Ward, P.L., 1991, Evolving geographic and (U-Th)/He dating of slip on the Crescent fault, the Cordilleran thrust belt and foreland basin system, patterns of Cenozoic magmatism in the North Ameri- Nevada: Eos (Transactions, American Geophysical western U.S.A: American Journal of Science, v. 304, can Cordillera: The temporal and spatial association of Union), v. 87, abs. T11D-0466. p. 105–168, doi:10.2475/ajs.304.2.105. magmatism and metamorphic core complexes: Journal Colgan, J.P., Shuster, D.L., and Reiners, P., 2007, Two- Dickinson, W.R., 1991, Tectonic setting of faulted Tertiary of Geophysical Research, v. 96, no. B8, 13201–13,224, phase Neogene extension of the northwestern Basin strata associated with the Catalina core complex in doi:10.1029/91JB00412. and Range deduced from thermochronology of a single southern Arizona: Geological Society of America Spe- Armstrong, R.L., Leeman, W.P., and Malde, H.E., 1975, sample: Eos (Transactions, American Geophysical cial Paper 264, 106 p. K-Ar dating, Quaternary and Neogene volcanic rocks Union), v. 88, abs. V33E–06. Dostal, J., Breitsprecher, K., Church, B.N., Thorkelson, D., of the Snake River Plain, Idaho: American Journal of Collettini, C., and Barchi, M.R., 2002, A low-angle normal fault and Hamilton, T.S., 2003, Eocene melting of Precam- Science, v. 275, p. 225–251, doi:10.2475/ajs.275.3.225. in the Umbria region (central Italy): A mechanical model brian lithospheric mantle: Analcime-bearing volcanic Axelrod, D.I., 1966a, The Eocene Copper Basin flora of for the related microseismicity: Tectonophysics, v. 359, rocks from the Challis-Kamloops belt of south central northeastern Nevada: University of California Publica- p. 97–115, doi:10.1016/S0040-1951(02)00441-9. British Columbia: Journal of Volcanology and Geo- tions in Geological Sciences 59, 125 p. Collettini, C., and Sibson, R.H., 2001, Normal faults, normal thermal Research, v. 126, p. 303–326, doi:10.1016 Axelrod, D.I., 1966b, Potassium-argon ages of some west- friction?: Geology, v. 29, p. 927–930, doi:10.1130/0091 /S0377-0273(03)00153-7. ern Tertiary floras: American Journal of Science, -7613(2001)029<0927:NFNF>2.0.CO;2. Draper, D.S., 1991, Late Cenozoic bimodal magmatism v. 264, p. 497–506, doi:10.2475/ajs.264.7.497. Compton, R.R., 1972, Geologic map of the Yost quadrangle, in the northern Basin and Range province of south- Best, M.G., and Christiansen, E.H., 1991, Limited extension Box Elder County, Utah, and Cassia County, Idaho: eastern Oregon: Journal of Volcanology and Geo- during peak Tertiary volcanism, Great Basin of Nevada U.S. Geological Survey Miscellaneous Geologic Inves- thermal Research, v. 47, p. 299–328, doi:10.1016 and Utah: Journal of Geophysical Research, v. 96, tigations Map I-672, 7 p., scale 1:31,680. /0377-0273(91)90006-L. no. B8, p. 13509–13528, doi:10.1029/91JB00244. Compton, R.R., 1975, Geologic map of the Park Valley quad- duBray, E.A., John, D.A., Sherrod, D.R., Evarts, R.C., Best, M.G., Barr, D.L., Christiansen, E.H., Gromme, S., rangle, Box Elder County, Utah, and Cassia County, Conrey , R.M., and Lexa, J., 2006, Geochemical data- Deino, A.L., and Tingey, D.G., 2009, The Great Basin Idaho: U.S. Geological Survey Miscellaneous Geologic base for volcanic rocks of the western cascades, Wash- Altiplano during the middle Cenozoic ignimbrite Investigations Map I-873, 6 p., scale 1:31,680. ington, Oregon, and California: U.S. Geological Survey flare-up: Insights from volcanic rocks: International Compton, R.R., 1983, Displaced Miocene rocks on the west U.S. Geological Survey Data Series DS-0155, 49 p. Geology Review, v. 51, p. 589–633, doi:10.1080 fl ank of the Raft River–Grouse Creek core complex, Dumitru, T.A., Gans, P.B., Foster, D.A., and Miller, E.L., /00206810902867690. Utah; tectonic and stratigraphic studies in the eastern 1991, Refrigeration of the western Cordilleran litho- Blakey, R.C., 2008, Pennsylvanian–Jurassic sedimentary Great Basin, in Miller, D.M., et al., eds., Tectonic and sphere during Laramide shallow-angle subduction: basins of the Colorado Plateau and Southern Rocky stratigraphic studies in the eastern Great Basin: Geo- Geology, v. 19, p. 1145–1148, doi:10.1130/0091-7613 Mountains, in Miall A.D., ed., Sedimentary basins of logical Society of America Memoir 157, p. 271–279. (1991)019<1145:ROTWCL>2.3.CO;2. the United States and Canada: Sedimentary Basins Compton, R.R., Todd, V.R., Zartman, R.E., and Naeser, Dumitru, T.A., Ernst, W.G., Wright, J.E., Wooden, J.L., of the World, Volume 5: Amsterdam, Elsevier B.V., C.W., 1977, Oligocene and Miocene metamorphism, Wells, R.E., Farmer, L.P., Kent, A.J.R., and Graham, p. 245–296, doi:10.1016/S1874-5997(08)00007-5. folding, and low-angle faulting in northwestern S.A., 2013, Eocene extension in Idaho generated

1464 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Multistage extension of the ARG metamorphic core complex

massive sediment fl oods into Franciscan trench and Harris, C.R., Hoisch, T.D., and Wells, M.L., 2007, Construc- ica Bulletin, v. 97, p. 603–618, doi:10.1130/0016-7606 into Tyee, Great Valley, and Green River basins: Geol- tion of a composite pressure-temperature path: Reveal- (1986)97<603:TMITNB>2.0.CO;2. ogy (in press). ing the synorogenic burial and exhumation history of Konstantinou, A., 2011, Off-axis Snake River plain mag- Eberly, L.D., and Stanley, T.B., 1978, Cenozoic stratigraphy the Sevier hinterland, USA: Journal of Metamorphic matism along an active extensional detachment: An and geologic history of southwestern Arizona: Geologi- Geology, v. 25, p. 915–934, doi:10.1111/j.1525-1314 example from the Jim Sage volcanic suite, southern cal Society of America Bulletin, v. 89, p. 921–940, doi: .2007.00733.x. ID: Geological Society of America Abstracts with Pro- 10.1130/0016-7606(1978)89<921:CSAGHO>2.0.CO;2. Hauser, E., Potter, C., Hauge, T., Burgess, S., Burtch, S., grams, v. 43, no. 5, p. 106. Egger, A.E., Dumitru, T.A., Miller, E.L., Savage, C.F.I., and Mutschler, J., Allmendinger, R., Brown, L., Kaufman, S., Link, P.K., and Johnston, S., 2008, Proterozoic paleogeog- Wooden, J.L., 2003, Timing and nature of Tertiary plu- and Oliver, J., 1987, Crustal structure of eastern Nevada raphy and stratigraphy of the Snake Range, eastern tonism and extension in the Grouse Creek Mountains, from COCORP deep seismic refl ection data: Geologi- Nevada and Albion–Grouse Creek Ranges, southern Utah: International Geology Review, v. 45, p. 497–532, cal Society of America Bulletin, v. 99, p. 833–844, doi: Idaho: Detrital zircon constraints and stratigraphic sur- doi:10.2747/0020-6814.45.6.497. 10.1130/0016-7606(1987)99<833:CSOENF>2.0.CO;2. prises: Geological Society of America Abstracts with Egger, A.E., Glen, J.M., and Ponce, D.A., 2010, The north- Heller, P.L., Bowdler, S.S., Chambers, H.P., Coogan, J.C., Programs, v. 40, no. 6, p. 145. western margin of the Basin and Range province. Part 2: Hagen, E.S., Shuster, M.W., Winslow, N.S., and Law- Long, S.P., 2012, Magnitudes and spatial patterns of ero- Structural setting of a developing basin from seismic ton, T.F., 1986, Time of initial thrusting in the Sevier sional exhumation in the Sevier hinterland, eastern and potential fi eld data: Tectonophysics, v. 488, p. 150– orogenic belt, Idaho-Wyoming and Utah: Geology, Nevada and western Utah, USA: Insights from a Paleo- 161, doi:10.1016/j.tecto.2009.05.029. v. 14, p. 388–391, doi:10.1130/0091-7613(1986)14 gene paleogeologic map: Geosphere, v. 8, p. 881–901, Ellis, B.S., Barry, T., Branney, M.J., Wolff, J.A., Bindeman, <388:TOITIT>2.0.CO;2. doi:10.1130/GES00783.1. I., Wilson, R., and Bonnichsen, B., 2010, Petrologic Henry, C.D., 2008, Ash-fl ow tuffs and paleovalleys in north- Ludwig, R.K., 2003, User’s manual for Isoplot 3.00. A geo- constraints on the development of a large-volume, eastern Nevada; Implications for Eocene paleogeog- chronological toolkit for Microsoft Excel: Berkeley high temperature, silicic magma system: The Twin raphy and extension in the Sevier hinterland, northern Geochronology Center Special Publication 4. Falls eruptive center, central Snake River Plain: Lithos, Great Basin: Geosphere, v. 4, p. 1–35, doi:10.1130 Mabey, D.R., and Wilson, C.W., 1973, Regional gravity v. 120, p. 475–489, doi:10.1016/j.lithos.2010.09.008. /GES00122.1. and magnetic surveys in the Albion Mountains area Ernst, W.G., 2010, Young convergent-margin orogens, climate, Henry, C.D., Colgan, J.P., McGrew, A.J., Snoke, A.W., and of southern Idaho: U.S. Geological Survey Open-File and crustal thickness; A Late Cretaceous–Paleogene Brueseke, M.E., 2011, Timing, distribution, amount, Report 73-165, 12 p. Nevadaplano in the American Southwest?: Litho- and style of Cenozoic extension in the northern Great MacCready, T., Snoke, A.W., Wright, J.E., and Howard, sphere, v. 2, p. 67–75, doi:10.1130/L84.1. Basin, in Lee, J., and Evans, J.P., eds., Geologic fi eld K.A., 1997, Mid-crustal fl ow during Tertiary exten- Fosdick, J.C., and Colgan, J.P., 2008, Miocene extension in trips to the Basin and Range, Rocky Mountains, Snake sion in the Ruby Mountains core complex, Nevada: the east range, Nevada; a two-stage history of normal River Plain, and terranes of the U.S. Cordillera: Geo- Geological Society of America Bulletin, v. 109, faulting in the northern Basin and Range: Geological logical Society of America Field Guide 21, p. 27–66, p. 1576–1594, doi:10.1130/0016-7606(1997)109<1576: Society of America Bulletin, v. 120, p. 1198–1213, doi:10.1130/2011.0021(02). MCFDTE>2.3.CO;2. doi:10.1130/B26201.1. Hintze, L.F., 1988, Geologic history of Utah: Brigham Young Martinez, C.M., 2000, Character of Miocene syn-tectonic Foster, D.A., Schafer, C., Fanning, M.C., and Hyndman, University Geology Studies Special Publication 7, sediments deposited adjacent to the Grouse Creek D.W., 2001, Relationships between crustal partial melt- 202 p. Mountains, northwestern Utah: Geological Society of ing, plutonism, orogeny, and exhumation: Idaho–Bitter- Hintze, L.F., Willis, G.C., Laes, D.Y., Sprinkel, D.A., and America Abstracts with Programs, v. 32, no. 7, p. 44. root batholith: Tectonophysics, v. 342, p. 313–350. Brown, K.D., 2000, Digital geologic map of Utah: Martinez, C.M., 2001, Characteristics of sedimentary basins Gans, P.B., 1987, An open-system, two-layer crustal stretch- Utah Geological Survey Map 179DM, scale 1:500,000. formed above low-angle detachment faults; examples ing model for the eastern Great Basin: Tectonics, v. 6, Hoisch, T.D., Wells, M.L., and Hanson, L.M., 2002, Pres- from the Basin and Range province, western U.S.: p. 1–12, doi:10.1029/TC006i001p00001. sure-temperature paths from garnet zoning; evidence Geological Society of America Abstracts with Pro- Gans, P.B., and Miller, E.L., 1983, Style of mid-Tertiary for multiple episodes of thrust burial in the hinterland grams, v. 33, no. 6, p. 391. extension in east-central Nevada, in Gurgel, K.D., ed., of the Sevier orogenic belt: American Mineralogist, McKenzie, D., Nimmo, F., Jackson, J.A., Gans, P.B., and Geologic excursions in the Overthrust belt and meta- v. 87, p. 115–131. Miller, E.L., 2000, Characteristics and consequences morphic core complexes of the intermountain region: Hoisch, T.D., Wells, M.L., and Grove, M., 2008, Age trends of fl ow in the lower crust: Journal of Geophysical Utah Geological and Mineral Survey Special Study 59, in garnet-hosted monazite inclusions from upper Research, v. 105, no. B5, p. 11029–11046, doi:10.1029 p. 107–160. amphibolite facies schist in the northern Grouse Creek /1999JB900446. Gans, P.B., Mahood, G.A., and Schermer, E.R., 1989, Syn- Mountains, Utah: Geochimica et Cosmochimica Acta Miller, D.M., 1978, Deformation associated with Big Bertha extensional magmatism in the Basin and Range province; v. 72, p. 5505–5520, doi:10.1016/j.gca.2008.08.012. dome, Albion Mountains, Idaho [Ph.D. thesis]: Los A case study from the eastern Great Basin: Geological Holdaway, M.J., 1971, Stability of andalusite and the alu- Angeles, University of California at Los Angeles, 510 p. Society of America Special Paper 233, 60 p. minosilicate phase diagram: American Journal of Sci- Miller, D.M., 1980, Structural geology of the northern Gaschnig, R.M., Vervoort, J.D., Lewis, R.S., and McClel- ence, v. 271, p. 97–131, doi:10.2475/ajs.271.2.97. Albion Mountains, south-central Idaho, in Crittenden, land, W.C., 2010, Migrating magmatism in the northern Humphreys, E.D., 1995, Post-Laramide removal of the M.D., Jr., et al., eds., Cordilleran metamorphic core US cordillera: In situ U-Pb geochronology of the Idaho Farallon slab, western United States: Geology, v. 23, complexes: Geological Society of America Memoir batholith: Contributions to Mineralogy and Petrology, p. 987–990, doi:10.1130/0091-7613(1995)023<0987: 153, p. 399–423. v. 159, p. 863–883, doi:10.1007/s00410-009-0459-5. PLROTF>2.3.CO;2. Miller, D.M., 1983, Strain on a gneiss dome in the Albion Gashawbeza, E.M., Klemperer, S.L., Wilson, C.K., and Humphreys, E., Hessler, E., Dueker, K., Farmer, G.L., mountains metamorphic core complex, Idaho: Ameri- Miller, E.L., 2008, Nature of the crust beneath northwest Erslev, E., and Atwater, T., 2003, How Laramide-age can Journal of Science, v. 283, p. 605–632, doi:10.2475 Basin and Range province from teleseismic receiver hydration of North American lithosphere by the Faral- /ajs.283.6.605. function data: Journal of Geophysical Research, v. 113, lon slab controlled subsequent activity in the western Miller, D.M., Armstrong, R.L., Bedford, D.R., and Davis, B10308, doi:10.1029/2007JB005306. United States: International Geology Review, v. 45, M., 2008, Geologic map and digital data base of the Gehrels, G.E., Valencia, V., and Pullen, A., 2006, Detrital p. 575–595, doi:10.2747/0020-6814.45.7.575. Almo quadrangle and City of Rocks National Reserve, zircon geochronology by laser-ablation multicollector Jackson, J.A., and White, N.J., 1989, Normal faulting in the Cassia County, Idaho: U.S. Geological Survey Open- ICPMS at the Arizona LaserChron Center: Paleontol- upper continental crust; observations from regions of File Report 2008–1103, 36 p., 1 sheet, scale 1:24,000. ogy Society Papers, v. 12, p. 67–76. active extension: Journal of Structural Geology, v. 11, Miller, E.L., and Gans, P.B., 1989, Cretaceous crustal struc- Gehrels, G.E., Valencia, V., and Ruiz, J., 2008, Enhanced p. 15–36, doi:10.1016/0191-8141(89)90033-3. ture and metamorphism in the hinterland of the Sevier precision, accuracy, effi ciency, and spatial resolution Janecke, S.U., and Snee, L.W., 1993, Timing and episodic- thrust belt, western U.S. Cordillera: Geology, v. 17, of U-Pb ages by laser ablation– multicollector–induc- ity of middle Eocene volcanism and onset of conglom- p. 59–62, doi:10.1130/0091-7613(1989)017<0059: tively coupled plasma–mass spectrometry: Geochem- erate deposition, Idaho: Journal of Geology, v. 101, CCSAMI>2.3.CO;2. istry Geophysics Geosystems, v. 9, Q03017, doi: p. 603–621, doi:10.1086/648252. Miller, E.L., Gans, P.B., Wright, J.E., and Sutter, J.F., 1988, 10.1029/2007GC001805. Johnson, B.R., and Raines, G.L., 1996, Digital representa- Metamorphic history of the east-central Basin and Gottardi, R., Teyssier, C., Mulch, A., Vennemann, T.W., and tion of the Idaho state geologic map: A contribution Range province: Tectonic setting and relationship to Wells, M.L., 2011, Preservation of an extreme transient to the Interior Columbia River Basin Ecosystem Man- magmatism, in Ernst, W.G., ed., Metamorphism and geotherm in the Raft River detachment shear zone: agement Project: U.S. Geological Survey Open-File crustal evolution, western coterminous United States: Geology, v. 39, p. 759–762, doi:10.1130/G31834.1. Report 95–690, 24 p. Rubey Volume 7: Englewood Cliffs, New Jersey, Pren- Grunder, A.L., 1993, Two-stage contamination during Kistler, R.W., and Lee, D.E., 1989, Rubidium, strontium, tice-Hall, p. 649–682. crustal assimilation; isotopic evidence from volcanic and strontium isotopic data for a suite of granitoid Miller, E.L., Dumitru, T.A., Brown, R.W., and Gans, P.B., rocks in eastern Nevada: Contributions to Mineral- rocks from the Basin and Range province, Arizona, 1999, Rapid Miocene slip on the Snake Range–Deep ogy and Petrology, v. 112, p. 219–229, doi:10.1007 California, Nevada, and Utah: U.S. Geological Survey Creek Range fault system, east-central Nevada: /BF00310456. Open-File Report 89–0199, 15 p. Geological Society of America Bulletin, v. 111, Grunder, A.L., 1995, Material and thermal roles of basalt in Klemperer, S.L., Hauge, T.A., Hauser, E.C., Oliver, J.E., and p. 886–905, doi:10.1130/0016-7606(1999)111<0886: crustal magmatism; Case study from eastern Nevada: Potter, C.J., 1986, The Moho in the northern Basin RMSOTS>2.3.CO;2. Geology, v. 23, p. 952–956, doi:10.1130/0091-7613 and Range province, Nevada, along the COCORP 40°N Mulch, A., Graham, S.A., and Chamberlain, C.P., 2006, (1995)023<0952:MATROB>2.3.CO;2. seismic-refl ection transect: Geological Society of Amer- Hydrogen isotopes in Eocene river gravels and paleo-

Geosphere, December 2012 1465

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021 Konstantinou et al.

elevation of the Sierra Nevada: Science, v. 313, Stanford, California, Stanford University, http://purl Wells, M.L., Snee, L.W., and Blythe, A.E., 2000, Dating of p. 87–89, doi:10.1126/science.1125986. .stanford.edu/hk878gp3950. major normal fault systems using thermochronology; Nutt, C.J., and Ludington, S.D., 2003, Intrusive rock data- Strickland, A., Miller, E.L., and Wooden, J., 2007, Timing of an example from the Raft River detachment, Basin base for the digital geologic map of Utah: U.S. Geo- ductile deformation in the Albion–Raft River–Grouse and Range, western United States: Journal of Geo- logical Survey Open-File Report 03–0486, 42 p. Creek (ARG) metamorphic core complex; preliminary physical Research, v. 105, no. B7, p. 16303–16327, Oriel, S.O., Williams, P.L. Covington, H.R., Keys, W.S., U-Pb SHRIMP results: Geological Society of America doi:10.1029/2000JB900094. and Shaver, K.C., 1978, Deep drilling data Raft River Abstracts with Programs, v. 39, no. 4, p. 5. Wells, M.L., Spell, T.L., Hoisch, T.D., Arriola, T., and geothermal area, Idaho: Standard American Oil Co., Strickland, A., Miller, E.L., and Wooden, J., 2011a, The tim- Zanetti, K.A., 2008, Laser-probe 40Ar/39Ar dat- Malta, Naf, and Strevell Petroleum test boreholes: U.S. ing of Tertiary metamorphism and deformation in the ing of strain fringes: Mid-Cretaceous synconver- Geological Survey Open-File Report 78–361, 2 p. Albion–Raft River–Grouse Creek metamorphic core gent orogen-parallel extension in the interior of the Palmer, H.C., and MacDonald, W.D., 2002, The Northeast complex, Utah and Idaho: Journal of Geology, v. 119, Sevier orogen: Tectonics, v. 27, TC3012, doi:10.1029 Nevada Volcanic Field: Magnetic properties and source p. 185–206, doi:10.1086/658294. /2007TC002153. implications: Journal of Geophysical Research, v. 107, Strickland, A., Miller, E.L., Wooden, J., Kozdon, R., and Wells, M.L., Hoisch, T.D., Cruz-Uribe, A.M., and Vervoort, no. B11, 2298, doi:10.1029/2001JB000690. Valley, J.W., 2011b, Syn-extensional plutonism and J.D., 2012, Geodynamics of synconvergent extension Perkins, M.E., and Nash, B.P., 2002, Explosive silicic vol- peak metamorphism in the Albion–Raft River–Grouse and tectonic mode switching: Constraints from the canism of the Yellowstone hotspot; The ash fall tuff Creek metamorphic core complex: American Jour- Sevier-Laramide orogen: Tectonics, v. 31, TC1002, record: Geological Society of America Bulletin, v. 114, nal of Science, v. 311, p. 261–314, doi:10.2475/04 doi:10.1029/2011TC002913. p. 367–381, doi:10.1130/0016-7606(2002)114<0367: .2011.01. Wernicke, B.P., 1981, Low-angle normal faults in the Basin ESVOTY>2.0.CO;2. Stockli, D.F., 1999, Regional timing and spatial distribution and Range Province: Nappe tectonics in an extend- Perkins, M.E., Nash, W.P., Brown, F.H., and Fleck, R.J., of Miocene extension in the northern Basin and Range ing orogen: Nature, v. 291, no. 5817, p. 645–648, 1995, Fallout tuffs of Trapper Creek, Idaho—A record Province [Ph.D. thesis]: Stanford, California, Stanford doi:10.1038/291645a0. of Miocene explosive volcanism in the Snake River University, 239 p. Wernicke, B.P., and Axen, G.J., 1988, On the role of isos- Plain volcanic province: Geological Society of Amer- Teyssier, C., Ferre, E.C., Whitney, D.L., Norlander, B., tasy in the evolution of normal fault systems: Geology, ica Bulletin, v. 107, p. 1484–1506, doi:10.1130/0016 Vanderhaeghe, O., and Parkinson, D., 2005, Flow of v. 16, p. 848–851, doi:10.1130/0091-7613(1988)016 -7606(1995)107<1484:FTOTCI>2.3.CO;2. partially molten crust and origin of detachments dur- <0848:OTROII>2.3.CO;2. Pierce, K.L., and Morgan, L.A., 1992, The track of the ing collapse of the Cordilleran orogen, in Bruhn, D., Whitney, D.L., Teyssier, C., and Vanderhaeghe, O., 2004, Yellow stone hotspot: Volcanism, faulting, and uplift, and Burlini, L., eds., High-strain zones: Structure and Gneiss domes and crustal ﬂ ow, in Whitney, D.L., et al., in Link, P.K., et al., eds., Regional geology of eastern physical properties: Geological Society of London Spe- eds., Gneiss domes in orogeny: Geological Society Idaho and western Wyoming: Geological Society of cial Publication 245, p. 39–64, doi:10.1144/GSL.SP of America Special Paper 380, p. 15–33, doi:10.1130 America Memoir 179, p. 1–53. .2005.245.01.03. /0-8137-2380-9.15. Pierce, K.L., Covington, H.R., Williams, P.L., and McIntyre, Thatcher, W., and Hill, D.P., 1991, Fault orientations in exten- Williams, P.L., Pierce, K.L., McIntyre, D.H., and Schmidt, D.H., 1983, Geologic map of the Cotterel Mountains sional and conjugate strike-slip environments and their P.W., 1974, Preliminary geologic map of the southern and the northern Raft River valley, Cassia County, implications: Geology, v. 19, p. 1116–1120, doi:10.1130 Raft River area, Cassia County, Idaho: U.S. Geologi- Idaho: U.S. Geological Survey Miscellaneous Investi- /0091-7613(1991)019<1116:FOIEAC>2.3.CO;2. cal Survey Open-File Report 74–1126, scale 1:24,000. gations I-1450, 1 sheet. Todd, V.R., 1980, Structure and petrology of a Tertiary gneiss Williams, P.L., Mabey, D.R., Pierce, K.L., Zohdy, A.A., Rehrig, W.A., and Reynolds, S.J., 1980, Geologic and geo- complex in northwestern Utah, in Crittenden, M.D., Ackermann, H., and Hoover, D.B., 1975, Geological chronologic reconnaissance of a northwest-trending Jr., et al., eds., Cordilleran metamorphic core com- and geophysical studies of a geothermal area in the zone of metamorphic core complexes in southern and plexes: Geological Society of America Memoir 153, southern Raft River valley, Idaho, abs. 2, in Garnish, western Arizona, in Crittenden, M.D., Jr., et al., eds., p. 349–383. J.D., ed., Development and Use of Geothermal Resources: eds., Cordilleran metamorphic core complexes: Geo- Van Buer, N.J., Miller, E.L., and Dumitru, T.A., 2009, Early Second United Nations Symposium, San Francisco, logical Society of America Memoir 153, p. 131–157. Tertiary paleogeologic map of the northern Sierra California, 20–29 May, 1975, doi:10.1016/0301-4215 Rey, P.F., Teyssier, C., and Whitney, D.L., 2009, The role of Nevada batholith and the northwestern Basin and Range: (75)90007-5. partial melting and extensional strain rates in the devel- Geology, v. 37, p. 371–374, doi:10.1130/G25448A.1. Williams, P.L., Covington, H.R., and Pierce, K.L., 1982, opment of metamorphic core complexes; Hot orogens: Vanderhaeghe, O., Teyssier, C., McDougall, I., and Dunlap, Cenozoic stratigraphy and tectonic evolution of the Raft Tectonophysics, v. 477, p. 135–144, doi:10.1016/j.tecto W.J., 2003, Cooling and exhumation of the Shuswap River Basin, Idaho; Cenozoic geology of Idaho: Idaho .2009.03.010. metamorphic core complex constrained by 40Ar/39Ar Bureau of Mines and Geology Bulletin 26, p. 491–504. Saltzer, S.D., and Hodges, K.V., 1988, The Middle Mountain thermochronology: Geological Society of America Wiltschko, D.V., and Dorr, J.A., 1983, Timing of deforma- shear zone, southern Idaho; Kinematic analysis of an early Bulletin, v. 115, p. 200–216, doi:10.1130/0016-7606 tion in overthrust belt and foreland of Idaho, Wyoming Tertiary high-temperature detachment: Geological Soci- (2003)115<0200:CAEOTS>2.0.CO;2. and Utah: American Association of Petroleum Geolo- ety of America Bulletin, v. 100, p. 96–103, doi:10.1130 Wells, M.L., 1997, Alternating contraction and extension gists Bulletin, v. 67, p. 1304–1322. /0016-7606(1988)100<0096:TMMSZS>2.3.CO;2. in the hinterlands of orogenic belts; an example from Wooden, J.L., Kistler, R.W., and Tosdal, R.M., 1999, Stron- Sheely, J.C., 2002, Kinematics and timing of normal fault- the Raft River Mountains, Utah: Geological Society tium, lead, and oxygen isotopic data for granitoid and ing in a metamorphic core complex, Grouse Creek of America Bulletin, v. 109, p. 107–126, doi:10.1130 volcanic rocks from the northern Great Basin and Mountains, Utah [M.S. thesis]: Las Vegas, University /0016-7606(1997)109<0107:ACAEIT>2.3.CO;2. Sierra Nevada, California, Nevada, and Utah: U.S. of Nevada, 292 p. Wells, M.L., 2001, Rheological control on the initial geom- Geological Survey Open-File Report 99–0569, 40 p. Smith, J.F., Jr., 1982, Geologic map of the Strevell 15-min- etry of the Raft River detachment fault and shear zone, Wright, J.E., and Wooden, J.L., 1991, New Sr, Nd, and ute quadrangle, Cassia County, Idaho: U.S. Geological western United States: Tectonics, v. 20, p. 435–457, Pb isotopic data from plutons in the northern Great Survey Miscellaneous Investigation I-1403. doi:10.1029/2000TC001202 Basin; Implications for crustal structure and granite Stacey, J.S., and Kramers, J.D., 1975, Approximation of ter- Wells, M.L., 2009, Geologic map of the Kelton Pass quad- petrogenesis in the hinterland of the Sevier thrust belt: restrial lead isotope evolution by a two-stage model: rangle, Box Elder County, Utah, and Cassia County, Geology, v. 19, p. 457–460, doi:10.1130/0091-7613 Earth and Planetary Science Letters, v. 26, p. 207–221, Idaho: Utah Geological Survey Miscellaneous Publica- (1991)019<0457:NSNAPI>2.3.CO;2. doi:10.1016/0012-821X(75)90088-6. tion 09–3, 30 p. Yonkee, W.A., and Weil, A.B., 2011, Evolution of the Wyo- Stewart, J.H., 1980, Regional tilt patterns of late Cenozoic Wells, M.L., and Hoisch, T.D., 2008, The role of mantle ming salient of the Sevier fold-thrust belt, northern basin-range fault blocks, western United States: Geologi- delamination in widespread Late Cretaceous extension Utah to western Wyoming, in Sprinkel, D.A., eds., cal Society of America Bulletin, v. 91, p. 460–464, doi: and magmatism in the Cordilleran orogen, western Sevier thrust belt: Northern and central Utah and adja- 10.1130/0016-7606(1980)91<460:RTPOLC>2.0.CO;2. United States: Geological Society of America Bulletin, cent areas: Utah Geological Association Publication Stewart, J.H., Carlson, J.E., Raines, G.L., Connors K.A., v. 120, p. 515–530, doi:10.1130/B26006.1. 40, p. 1–56. Moyer L.A., and Miller, R.J., 2003, Spatial digital Wells, M.L., Hoisch, T.D., Peters, M.T., Miller, D.M., Wolff, Yonkee, W.A., Parry, W.T., Bruhn, R.L., and Cashman, P.L., database for the geologic map of Nevada: U.S. Geo- E.D., and Hanson, L.M., 1998, The Mahogany Peaks 1989, Thermal models of thrust faulting: Constraints logical Survey Open-File Report 03–66, 33 p. fault, a Late Cretaceous–Paleocene (?) normal fault in from ﬂ uid-inclusion observations, Willard thrust sheet, Strickland, A., 2010, Polyphase deformation and metamor- the hinterland of the Sevier orogen: Journal of Geol- Idaho-Utah-Wyoming thrust belt: Geological Society phism: A geochronologic perspective [Ph.D. thesis]: ogy, v. 106, p. 623–634, doi:10.1086/516046. of America Bulletin, v. 101, p. 304–313.

1466 Geosphere, December 2012

Downloaded from http://pubs.geoscienceworld.org/gsa/geosphere/article-pdf/8/6/1429/3346353/1429.pdf by guest on 01 October 2021