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doi: 10.1111/ter.12001 A non-collisional, accretionary Sveconorwegian orogen

Trond Slagstad,1 Nick M. W. Roberts,2,3 Mogens Marker,1 Torkil S. Røhr1 and Henrik Schiellerup1 1Geological Survey of , Postboks 6315 Sluppen, 7491 Trondheim, Norway; 2Department of Geology, University of Leicester, Leicester, LE1 7RH, UK; 3NERC Isotope Geosciences Laboratory, Keyworth, Nottingham, NG12 5GG, UK

ABSTRACT The late Mesoproterozoic Sveconorwegian orogen in southwest in the period 990–920 Ma. This magmatic and metamorphic is traditionally interpreted as the eastward continuation evolution may be better understood as reflecting a long-lived of the Grenville orogen in Canada, resulting from collision with accretionary margin, undergoing periodic compression and Amazonia, forming a central part in the assembly of the extension, than continent–continent collision. This study has . We challenge this conventional view based on implications for Grenville–Sveconorwegian correlations, com- results from recent work in southwest Norway demonstrating parisons with modern continental margins, Rodinia reconstruc- voluminous -related magmatism in the period tions and how we recognize geodynamic settings in ancient 1050–1020 Ma, followed by geographically restricted high- orogens. T ⁄ medium-P between 1035 and 970 Ma, suc- ceeded by ferroan magmatism over large parts of south Norway Terra Nova, 00, 1–8, 2012

Introduction Accretionary orogenesis, involving years of the onset of collision (Beau- gian orogenic belt is widely regarded oceanic subduction and accre- mont et al., 2010; Jamieson et al., as a Himalayan-type and -scale oro- tion along a convergent margin, and 2010; Rivers, 2012). Evidence of this gen (e.g. Bingen et al., 2008b; Hynes continent–continent collision between is seen in collisional orogens, such as and Rivers, 2010) resulting from col- two major land masses, represent two the and the lision with an unknown continent, very different geodynamic regimes Caledonides (e.g. Kalsbeek et al., possibly Amazonia, to the south. This (Cawood et al., 2009). Nevertheless, 2001). In contrast, syn-orogenic mag- orogen is typically regarded as form- orogen-scale cross-sections of the col- matism in accretionary orogens is ing an integral part in the assembly of lisional Tibetan Plateau (Yin and typically calc-alkaline with mixed the Rodinia supercontinent (refs. in Harrison, 2000; Searle et al., 2009) crust- sources (e.g. Ort et al., Fig. 1). The Li et al. (2008) Rodinia and the accretionary Altiplano–Puna 1996; Davidson and Arculus, 2006), reconstruction is the most recent advo- Plateau (Elger et al., 2005; McQuarrie and may vary periodically in volume cating this ÔclassicÕ Baltica–– et al., 2005) show a number of simi- and composition if the orogen alter- Amazonia configuration (Fig. 1A); larities, including major crustal short- nates between compression and exten- however, other reconstructions exist ening, crustal-scale zones and sion (Kemp et al., 2009). The style of that are incompatible with this classic high-grade metamorphism resulting in high-grade metamorphism and P–T interpretation. The most radical of mid-crustal partial melting. Whereas, conditions will also differ, with colli- these alternative reconstructions is the geodynamic settings are relatively sional orogens characterized by that of Evans (2009), who suggested easy to determine in these modern mid-crustal temperatures typically that the Baltica–Laurentia margin was orogens, distinguishing between them <800 C (e.g. Jamieson et al., 2004), external, facing a large ocean to the in ancient orogens, where causal rela- whereas accretionary orogens under- southwest, with Amazonia located tionships are generally obscured or going periodic extension ⁄compression north in Rodinia (Fig. 1B). removed by later geological processes, may reach temperatures up to 900 C Modern orogenic systems com- is far from straightforward. Conti- at similar crustal levels, over compar- monly display significant along-strike nent–continent collision involves atively geographically restricted areas variations in tectonic style. For exam- thrusting of a continent and its lead- (Collins, 2002). Thus, the timing and ple, the collisional Himalayan orogen ing, passive margin beneath the over- composition of pre-, syn- and post- continues south-eastwards to become riding continental plate. Burial of orogenic magmatism and the style of the accretionary Indonesian arc, and the passive-margin sediments to mid- high-grade metamorphism may be westwards into the active arc in Mak- crustal levels results in radioactive two of the most powerful ways of ran, with a combined length of over self-heating and extensive dehydration determining the geodynamic settings 5000 km. The Grenville–Sveconorwe- melting typically within c. 20 million of ancient orogens. gian orogenic belt is similar in scale The Sveconorwegian Province in and identifying variations of this type Correspondence: Dr. Trond Slagstad, Geo- southwest Baltica is commonly inter- along the length of the orogen is logical Survey of Norway, Leiv Eirikssons- preted as the eastward continuation of essential for constraining the presently vei 39, Trondheim 7491, Norway. Tel.: the Grenville Province in Canada (e.g. incompatible reconstructions of Rodi- +47 73 90 42 29; fax: +47 73 92 16 20; Gower et al., 1990; Karlstrom et al., nia. Here, we focus on the magmatic e-mail: [email protected] 2001), and the Grenville–Sveconorwe- evolution of the Sveconorwegian

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they interpreted to reflect short-lived imparted on the SMB. The main (A) subduction of the southwest margin of crust-forming event in south Norway Baltica prior to continent–continent was at c. 1500 Ma (Bingen et al., collision. Figure 2 shows a new gen- 2005), and the available isotopic data Laurentia Baltica eralized regional map of south Nor- (Fig. 4C) show that a simple remelting way based on several years of of this crust, as would be expected mapping, and indicates locations of during a continent–continent colli- Study area new geochronological and geochemi- sion, cannot account for the isotopic Amazonia cal data from pre- to syn-Sveconor- composition of SMB rocks. Nd–Sr wegian rocks. The prefixes mixing calculations by Andersen et al. 1000 km pre-, syn-, late- and post- used in the (2001) suggest that the augen Sveconorwegian orogen (Baltica) text are used relative to the timing of has a 65–80% mantle-derived (B) { Grenville orogen (Laurentia) high-grade Sveconorwegian metamor- component. Moreover, the onset of Sunsas orogen (Amazonia) phism in southwest Baltica, defined by SMB magmatism 15 Ma prior to Bingen et al. (2008a) as between c. high-grade metamorphism is inconsis- 1035 and 970 Ma (Fig. 3), with conti- tent with crustal reworking. We there- Amazonia nent–continent collision believed to fore interpret the available geochemical have initiated at c. 1050 Ma. Methods and isotopic data to suggest formation and data are presented in Electronic of the SMB in a continental magmatic Supplements 1–4. These undeformed arc between c. 1050 and 1020 Ma. Laurentia to weakly deformed pre- ⁄syn-Sveco- Contemporaneous magmatism with Baltica norwegian form a NNW- transitional calc-alkaline–anorogenic trending belt several tens of kilometres affinity in Vest- (1035 ± 2 Ma Study area wide, i.e. significantly wider than the Fennefoss augen gneiss, Bingen and Feda augen gneiss (Fig. 2). We coin van Breemen, 1998), and ferroan mag- Fig. 1 Rodinia maps vary significantly, the term Magmatic Belt (SMB) matism in Aust-Agder (1036 ± 23 Ma reflecting the difficulties in reconstruct- for this granitoid belt, of which the Rosskreppfjord , Andersen ing Precambrian where Feda augen gneiss is a constituent. et al., 2002) and Telemark (1024 ± 24 the palaeomagnetic record is sparse, Although -facies conditions Ma Otternes granite, Andersen et al., palaeontological data are absent and have been reached locally in the study 2007), requires a heat source for geological information is commonly area, the investigated granitoids gen- crustal melting, and a degree of rela- obscured by later geological events. (A) erally reached only facies. tively juvenile mantle input to produce ÔClassicÕ configuration with the Lauren- We therefore interpret our zircon U– their isotopic signatures (Andersen tia–Baltica margin facing Amazonia, Pb dates to reflect igneous crystalliza- et al., 2009). This is compatible with roughly along the lines proposed by tion rather than later metamorphic lithospheric thinning and astheno- Cawood et al. (2007), Dalziel (1997), overprinting, in line with the textural spheric uprise, indicating an exten- et al. et al. Pisarevsky (2003), Li (2008). and compositional data from the zir- sional setting at this time, i.e. intra- or (B) Alternative reconstruction with con grains. The age data show that back-arc, rather than compressional, Amazonia located north of Laurentia, magmatism in the SMB was continu- and show that this magmatic phase with the Laurentia–Baltica margin fac- ing a Pacific-scale ocean, proposed by ous from c. 1050 to 1020 Ma, affected a large portion of south Nor- Evans (2009). and overlapped early Sveconorwegian way. This interpretation of the SMB is metamorphism by c. 15 Ma. Geochem- incompatible with collision at ically, the are calc-alkaline, 1050 Ma, as proposed earlier, or at orogen, how it can be interpreted in magnesian and similar to ÔCordilleranÕ any time before 1020 Ma. terms of accretionary rather than granites as defined by Frost et al. collisional orogenesis, and its bearing (2001) (Fig. 4A). Primitive mantle- 990–920 Ma late- to post- on models of the Laurentia–Baltica normalized trace-element patterns Sveconorwegian magmatism margin and Rodinia reconstructions. (Fig. 4B inset) display enrichments in large ion lithophile elements, negative Following and overlapping Sveconor- 1050–1020 Ma pre- to syn- Nb–Ta anomalies and an overall neg- wegian high-grade metamorphism, Sveconorwegian, arc-related atively sloping trend with increasing widespread ferroan (ÔA-typeÕ), horn- magmatism in southwest Norway compatibility, typical of subduction- blende-biotite granite magmatism zone magmas. This arc-like signature, between 990 and 920 Ma (HBG suite Sveconorwegian-age calc-alkaline as represented by a negative Nb–Ta of Vander Auwera et al., 2003, 2011), magmatism in southwest Norway was anomaly, may be inherited during and anorthosite-mangerite-charnockite first documented by Bingen (1989), melting of pre-existing crust; however, (AMC) magmatism in the Rogaland who identified a relatively narrow, N– both older and younger ferroan grani- Igneous Complex between 950 and S-trending belt of porphyritic grani- toids within the region that have a 920 Ma (Scha¨ rer et al., 1996; Ander- toids referred to as the Feda augen large crustal input (Andersen et al., sen and Griffin, 2004; Vander Auw- gneiss. Later, dating by Bingen and 2009) do not exhibit this anomaly era et al., 2011), is recorded in the van Breemen (1998) yielded an age of (Fig. 4B), suggesting that an addi- Sveconorwegian Province (Figs 2, 3). 1051 Ma for this augen gneiss, which tional subduction-zone signature was For simplicity, we use the terms HBG

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Fig. 2 Simplified geological map of the western and central Sveconorwegian Province based on previously published maps by the Geological Survey of Norway. The apostrophes in Idefjorden ÔterraneÕ have been added because of uncertainties regarding the terrane status of this unit. The Sirdal Magmatic Belt is based on new, unpublished mapping. The dotted pattern indicates the previously inferred extent of Sveconorwegian-age magmatism in south Norway (Feda). The new mapping shows that Sveconorwegian magmatism was significantly more voluminous than previously thought. Published age data from compilation by Bingen and Solli (2009). RVA, Rogaland–Vest-Agder sector; SU, Suldal sector. and AMC suite here, but acknowl- Evidence for collapse comes from line ⁄ferroan and ferroan magmatism edge that this is a lumperÕs approach Re–Os dating of molybdenite from inboard of, and partly within, the and that further work may warrant a quartz and pegmatite veins in south- SMB between c. 1035 and 1025 Ma, different subdivision. Geochemical west Norway, but large-scale exten- may indicate an extensional conver- and isotopic data from the AMC sional structures to support gent setting at least periodically dur- and HBG suites indicate mixed lower this interpretation have not been ing SMB arc magmatism, but the crustal, juvenile and mature sources described. The duration of late- ⁄ evidence for this is as yet weak. The (Vander Auwera et al., 2011 and refs. post-orogenic magmatism is also sig- cessation of magmatism at 1020 Ma, therein). Vander Auwera et al. (2011) nificantly longer than that ascribed to and onset of high-grade metamor- recently suggested that the mafic late- ⁄post-orogenic extension or slab phism slightly earlier at c. 1035 Ma, constituents of the Feda suite (part break-off following continental colli- could reflect either continental colli- of the SMB) were the most likely sion in other orogens (Atherton and sion as suggested by other workers in juvenile source of both the HBG and Ghani, 2002; Neilson et al., 2009). the Sveconorwegian orogen, or a flat- AMC suite. This interpretation is Formation of the HBG and AMC tening of the subducting slab, e.g. as a consistent with geographically wide- suites therefore appear inconsistent result of subduction of an oceanic spread magmatism during formation with a short-lived ÔcollapseÕ event. plateau (Collins, 2002; Martinod of the SMB. A relatively dry, lower et al., 2010) or changes in convergence crustal source, possibly as a result of rate or geometry (Cawood and An accretionary Sveconorwegian Sveconorwegian granulite facies Buchan, 2007; Cawood et al., 2011). orogen. A viable alternative to metamorphism, appears to be re- For reasons outlined below, we prefer collision? quired for the post-orogenic AMC the non-collisional interpretation. magmatism, whereas a more hy- Figure 5 schematically presents an Magmatism in the SMB continued drated lower to infra-crustal source alternative tectonic model for the c. 15 Ma after the onset of high-grade is required for some of the earlier and Sveconorwegian evolution of south- metamorphism. This may be difficult contemporaneous ferroan granites west Baltica. Formation of the SMB, to reconcile with a simple collision (Vander Auwera et al., 2003; Boga- interpreted to be subduction-related, model in which arc magmatism ceases erts et al., 2006). HBG and AMC started at c. 1050 Ma, well before the when one of the continents enters the magmatism is generally interpreted to onset of high-grade metamorphism subduction zone. In contrast, com- result from post-orogenic gravita- (Fig. 3), and was continuous until pression related to a change from tional collapse (Bingen et al., 2006). c. 1020 Ma. Transitional calc-alka- steep- to flat-slab subduction may

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E Eastern segment granulite- n = 8 & amphibolite-facies rocks HP amphibolite Eastern segment & granulite facies -facies rocks 1050-1025

HBG n = 10 Idefjorden terrane Bohus granite amphibolite-facies & granulite-facies rocks

Flå granite n = 7 Kongsberg terrane amphibolite-facies rocks Amphibolite facies 1110-1080 Bamble terrane granite granite amphibolite-facies domain MP granulite facies 1140-1125 Bamble terrane granulite-facies domain

n = 25 Transitional calc-alkaline to ferroan Telemark & Suldal sectors amphibolite-facies rocks Ferroan

M2 contact M1 amphibolite & SMB n = 41 Rogaland-Vest Agder sector metamorph. MP granulite facies & S of Telemark sector 1035-970 amphibolite-facies domain decompression Metamorphism Magmatism Rogaland-Vest Agder sector granulite-facies domain

W

900 950 1000 1050 1100 1150 Age (Ma)

Fig. 3 Timing of high-grade metamorphism and magmatism in the Sveconorwegain Province, from Bingen et al. (2008a), compared with probability density distributions of published U–Pb ages from Sveconorwegian crustal sectors. All ages are plotted, including minor dykes and pegmatites. The age of major units are indicated in the plots showing the Kongsberg ⁄ Bamble- and Idefjorden data, due to limited overlap between these and the age of minor units. All ages from the Eastern Segment are from smaller dykes and pegmatites with unknown regional significance. Data from Bingen and Solli (2009) and this study. Original references and brief source descriptions are listed in Electronic Supplement 4. temporally overlap arc magmatism for high-grade Sveconorwegian metamor- distinguishes the Sveconorwegian several million years (Espurt et al., phism argues against the development evolution from that of many other 2008). The area undergoing high- of an orogenic plateau. Even if a collisional orogenic belts, such as grade metamorphism at 1035– plateau had formed in the Sveconor- the Greenland Caledonides and the 970 Ma was geographically restricted wegian Province at this time, it would Himalayas, where such rocks are to the Rogaland–Vest-Agder sector in itself not constitute evidence of widespread. (Figs 2, 3), with areas further east collision, as major plateaus may also High-grade metamorphism and (Telemark sector) undergoing only form in accretionary settings (cf., magmatic quiescence in southwest low-grade metamorphism at this time Altiplano–Puna plateau). Thus, the Norway was succeeded by geograph- (Bingen et al., 2008a). Peak metamor- timing, style and geographical distri- ically widespread, ferroan granite phic temperatures at c. 1000–1010 Ma bution of Sveconorwegian high-grade magmatism between c. 990 and have been estimated at >800–900 C metamorphism do not require conti- 920 Ma (Figs 2, 3), which requires a at mid-crustal levels (6–7 kbar) nent collision, and are more in line major, long-lived thermal event that (Drueppel et al., 2008; Elsaesser et al., with models of arc ⁄ back-arc extension can only be explained by invoking 2008), higher than those normally and compression as a result of a upwelling asthenosphere as a result of attained in collisional orogens (e.g. periodically retreating and advancing extension and ⁄or lithospheric-mantle Jamieson et al., 2004). Similar P–T subduction zone (Collins, 2002; . There is no evidence of conditions could potentially be at- Cawood et al., 2009). If one accepts large-scale extensional structures tained following delamination of sub- an arc setting for the SMB, Figure 3 that would be expected if the orogen continental lithospheric mantle under shows that there is a lack of had undergone orogenic collapse, an orogenic plateau. However, the syn-collisional magmatism in the and the metamorphic evidence shows limited geographical distribution of Sveconorwegian Province, which that most of south Norway was

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(A) 1.0

Ferroan 0.9

0.8 Fe-no.

0.7 Magnesian

FeOt/(FeOt+MgO) 0.6 Sirdal Magmatic Belt (1050-1020 Ma) HBG-suite (990 - 920 Ma) Feda augen gneiss (1050 Ma) s Pre-Svecon. ferroan (1130-1160 Ma) Fennefoss augen gneiss (1035 Ma) 0.5 50 60 70 80 SiO2 (B) 7 1000 Rock / Avg. SMB Avg. Feda 6 Primitive Mantle Avg. Fennefoss 100 Otternes Rosskreppfjord 5 HBG-suite 10 Pre-Svecon. ferroan 4 1 3 SMB .1 Ba U Ta La Pb Sr Nd Sm Ti Y Lu Rb Th Nb K Ce Pr P Zr Eu Dy Yb 2 Sliding normalization 1

0 2 O UThRbTaNb O Ba Sr Zr Hf Ce NdSm Y Yb 2 2 K TiO CaO Na (C) 8

6

4

2

Nd 0 ε

–2 Feda augen gneiss (felsic) –4 Feda augen gneiss (mafic) HBG-suite / A-type granites Granites (see text) –6 Supracrustals (felsic) Supracrustals (mafic) –8 900 1000 1100 1200 1300 1400 1500 1600 Age (Ma)

Fig. 4 Major and trace-element compositions of the SMB, the coeval Feda and Fennefoss augen , Rosskreppfjord and Otternes granites, the younger HBG suite and pre-Sveconorwegian (c. 1130–1160 Ma) ferroan granites. (A) SiO2 vs. FeOt ⁄ (FeOt+MgO) plot defined by Frost et al. (2001); the Fe-number line separates ferroan from magnesian granitoids. Dark grey field outlines Cordilleran granitoids defined by Frost et al. (2001). (B) Sliding normalization multi-element plot, following Lie´ geois et al. (1998) and Vander Auwera et al. (2011). Note the negative Nb–Ta anomaly in SMB and Feda. Inset: Primitive Mantle- normalized multi-element plot of SMB. Primitive Mantle values from Sun and McDonough (1989). Data for HBG suite from Bogaerts et al. (2003) and Vander Auwera et al. (2003), Feda from Bingen (1989), Fennefoss from Bingen and van Breemen (1998), Otternes, Rosskreppfjord and pre-Sveconorwegian ferroan granites from Andersen et al. (2009). (C) Nd vs. time for Mesoproterozoic magmatism in the Telemark ⁄ Rogaland-Vest-Agder sectors; the grey field shows the evolution of c. 1500 Ma crust (data from Vander Auwera et al. (2011) and refs. therein). The depleted mantle has been calculated with the model of DePaolo et al. (1991).

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(A)

(B)

(C)

Fig. 5 Tectonic cartoon illustrating a possible non-collisional model for the magmatic and metamorphic evolution of the Sveconorwegian orogen from c. 1050 to 920 Ma. RVA, Rogaland–Vest-Agder sector; Idef. Ôter.Õ, Idefjord ÔterraneÕ. at relatively low- to medium- a relatively short-lived magmatic Implications for Rodinia grade, which probably means that pulse, akin to that expected from reconstructions the lithospheric thickness required orogenic collapse, whereas back-arc for large-scale upper-mantle ⁄lower- extension and lower crustal melting Classic reconstructions of Rodinia crustal delamination was too small. can account for more protracted mag- involve collision between Laurentia, We cannot exclude the possibility that matism, and is the favoured mecha- Baltica and Amazonia, forming the presently exposed rocks in south Nor- nism here; however, an improved Grenville, Sveconorwegian and Sun- way were situated at high-crustal lev- understanding of the post-orogenic sas orogenic belts respectively (Li els during Sveconorwegian magmatism in south Norway is re- et al., 2008 and references therein). metamorphism; but proponents of quired before this issue can be re- One notable exception to this inter- collision ⁄ delamination would then solved. AMC magmatism between c. pretation is that of Evans (2009), who need to rely on an unobservable meta- 950 and 920 Ma was most likely a restored Amazonia to a more north- morphic event to explain the forma- result of delamination or convective erly position in Rodinia, adjacent to tion of the HBG suite. Alternative thinning of the thickened mantle root the West Africa and Congo cratons, mechanisms for explaining this long- to the SMB arc (cf., Corrigan and leaving the late Mesoproterozoic lived magmatic event, not requiring a Hanmer, 1997), and partial melting of Grenville–Sveconorwegian margin significant preceding thickening of the dehydrated lower crust, which may facing a large ocean to the southwest continental , are founder- have resisted earlier eclogitization and (Fig. 1B). A cordilleran-type accre- ing of the flat slab at c. 990 Ma or a delamination on account of its dry tionary margin is consistent with return to an extensional subduc- nature (Bjørnerud and Austrheim, our interpretations from southwest tion regime with back-arc exten- 2004; Jackson et al., 2004). This inter- Baltica. In contrast, the Grenville sion affecting most of south Norway. pretation is consistent with that of Province lacks the voluminous Foundering would probably produce Vander Auwera et al. (2011). syn-collisional magmatism (e.g. Carr

6 2012 Blackwell Publishing Ltd Terra Nova, Vol 00, No. 0, 1–8 T. Slagstad et al. • A non-collisional, accretionary Sveconorwegian orogen ...... et al., 2000) that we show character- Andersen, T., Graham, S. and Sylvester, . Geology, 32, izes the Sveconorwegian Province. A.G., 2007. Timing and tectonic signifi- 765–768. Also, Grenville-age basement in the cance of Sveconorwegian A-type granitic Bogaerts, M., Scaillet, B., Lie´ geois, J.-P. Appalachian orogen appears to be magmatism in Telemark, southern Nor- and Vander Auwera, J., 2003. Petrology exotic to Laurentia, and was probably way:New results from laser-ablation and geochemistry of the grano- ICPMS U-Pb dating of zircon. NGU diorite (southern Norway) and the role of accreted during Rodinia assembly Bull., 447, 17–31. fractional crystallisation in the genesis of (Fisher et al., 2010). It is possible that Andersen, T., Graham, S. and Sylvester, ferro-potassic A-type gran- there were significant along-strike A.G., 2009. The geochemistry, Lu-Hf ites. Precambr. Res., 124, 149–184. variations in tectonic style along the isotope systematics, and petrogenesis of Bogaerts, M., Scaillet, B. and Auwera, J.V., Grenville–Sveconorwegian margin, Late Mesoproterozoic A-type granites in 2006. Phase equilibria of the Lyngdal similar to those observed along the southwestern Fennoscandia. Can. granodiorite (Norway): implications for Himalayan–Indonesian system; that Mineral., 47, 1399–1422. the origin of metaluminous ferroan gra- the evolution observed in the Sveco- Atherton, M.P. and Ghani, A.A., 2002. nitolds. J. Petrol., 47, 2405–2431. norwegian Province is a localized Slab breakoff: a model for Caledonian, Carr, S.D., Easton, R.M., Jamieson, R.A. Late Granite syn-collisional magmatism phenomenon in an overall collisional and Culshaw, N.G., 2000. Geologic in the orthotectonic (metamorphic) zone transect across the Grenville orogen of setting; or that models suggesting a of Scotland and Donegal, Ireland. Ontario and New York. Can. J. Earth correlation between the Grenville and Lithos, 62, 65–85. Sci., 37, 193–216. Sveconorwegian Provinces may be Beaumont, C., Jamieson, R.A. and Cawood, P.A. and Buchan, C., 2007. incorrect (cf., Gower et al., 2008). In Nguyen, M.H., 2010. Models of large, Linking accretionary orogenesis with any case, this study shows that the hot orogens containing a collage of re- supercontinent assembly. Earth-Sci. generally rather simplistic view of worked and accreted . Can. J. Rev., 82, 217–256. Grenville–Sveconorwegian orogenic Earth Sci., 47, 485–515. Cawood, P.A., Nemchin, A.A., Strachan, processes and Rodinia assembly and Bingen, B., 1989. Geochemistry of Sveco- R.A., Prave, A.R. and Krabbendam, M., reconstructions needs to be revised. norwegian augen gneisses from SW 2007. Sedimentary basin and detrital Norway at the amphibolite-granulite zircon record along East Laurentia and facies transition. Nor. Geol. Tidsskr., 69, Baltica during assembly and breakup of Acknowledgements 177–189. Rodinia. J. Geol. Soc. London, 164, 257– Bingen, B. and van Breemen, O., 1998. 275. We thank Bernard Bingen, Tom Andersen, Tectonic regimes and terrane boundaries Cawood, P.A., Kro¨ ner, A., Collins, W.J, Giulio Viola and Simone Sauer for stimu- in the high-grade Sveconorwegian belt of Kusky, T.M., Mooney, W.D. and lating discussions of the ideas presented SW Norway, inferred from U-Pb zircon Windley, B.F., 2009. Accretionary oro- here. Reviews of an earlier version by geochronology and geochemical signa- gens through Earth history. In: Earth Brendan Murphy, Tom Andersen and ture of augen gneiss suites. J. Geol. Soc. Accretionary Systems in Space and Time Toby Rivers helped strengthen key argu- London, 155, 143–154. (P.A. Cawood and A. Kro¨ ner, eds), pp. ments in our interpretation. We also thank Bingen, B. and Solli, A., 2009. Geochro- 1–36. Geological Society of London, Ian Dalziel, Peter Cawood and an anony- nology of magmatism in the Caledo- London. mous reviewer for comments to this man- nian and Sveconorwegian belts of Cawood, P.A., Leitch, E.C., Merle, R.E. uscript. The Nordsim facility is operated Baltica: synopsis for detrital zircon and Nemchin, A.A., 2011. Orogenesis under an agreement between the research provenance studies. Norw. J. Geol., 89, without collision: stabilizing the Terra funding agencies of Denmark, Norway and 267–290. Australis accretionary orogen, eastern Sweden, the Geological Survey of Finland Bingen, B., Ska˚ r, Ø., Marker, M., Sig- Australia. Geol. Soc. Am. Bull., 123, and the Swedish Museum of Natural His- mond, E.M.O., Nordgulen, Ø., Rag- 2240–2255. tory. This is NORDSIM contribution 322 nhildstveit, J., Mansfeld, J., Tucker, Collins, W.J., 2002. Hot orogens, tectonic R.D. and Lie´ geois, J.-P., 2005. Timing of switching, and creation of continental continental building in the Sveconorwe- References crust. Geology, 30, 535–538. gian orogen, SW Scandinavia. Norw. J. Corrigan, D. and Hanmer, S., 1997. An- Andersen, T. and Griffin, W.L., 2004. Lu- Geol., 85, 87–116. orthosites and related granitoids in the Hf and U-Pb isotope systematics of zir- Bingen, B., Stein, H.J., Bogaerts, M., Bolle, Grenville orogen: a product of convec- cons from the Storgangen intrusion, O. and Mansfeld, J., 2006. Molybdenite tive thinning of the lithosphere? Geology, Rogaland Intrusive Complex, SW Nor- Re–Os dating constrains gravitational 25, 61–64. way: implications for the composition collapse of the Sveconorwegian orogen, Dalziel, I.W.D., 1997. Neoproterozoic- and evolution of Precambrian lower SW Scandinavia. Lithos, 87, 328–346. Paleozoic geography and : Review, crust in the . Lithos, 73, Bingen, B., Davis, W.J., Hamilton, M.A., hypothesis, environmental speculation. 271–288. Engvik, A.K., Stein, H.J., Ska˚ r, Ø and Geol. Soc. Am. Bull., 109, 16–42. Andersen, T., Andresen, A. and Sylvester, Nordgulen, Ø., 2008a. Geochronology of Davidson, J.P. and Arculus, R.J., 2006. A.G., 2001. Nature and distribution of high-grade metamorphism in the Sveco- The significance of Phanerozoic arc deep crustal reservoirs in the southwest- norwegian belt, S Norway: U-Pb, Th-Pb magmatism in generating continental ern part of the Baltic Shield: evidence and Re-Os data. Norw. J. Geol., 88, crust. In: Evolution and Differentiation of from Nd, Sr and Pb isotope data on late 13–42. the Continental Crust (M. Brown and T. Sveconorwegian granites. J. Geol. Soc. Bingen, B., Nordgulen, Ø. and Viola, G., Rushmer, eds), pp. 135–172. Cambridge London, 158, 253–267. 2008b. A four-phase model for the University Press, Cambridge. Andersen, T., Andresen, A. and Sylvester, Sveconorwegian , SW Scandi- DePaolo, D.J., Linn, A. and Schubert, G., A.G., 2002. Timing of late- to post- navia. Norw. J. Geol., 88, 43–72. 1991. The continental crustal age distri- tectonic Sveconorwegian granitic Bjørnerud, M.G. and Austrheim, H., 2004. bution: methods of determining mantle magmatism in South Norway. Inhibited eclogite formation: the key to separation ages from Sm-Nd isotopic NGU Bull., 440, 5–18. the rapid growth of strong and buoyant data and application to the southwestern

2012 Blackwell Publishing Ltd 7 A non-collisional, accretionary Sveconorwegian orogen • T. Slagstad et al. Terra Nova, Vol 00, No. 0, 1–8 ......

United States. J. Geophys. Res., 96, of mountain belts. Geology, 32, of the Siluro-Devonian post-collision 2071–2088. 625–628. magmatic episode in the Grampian Drueppel, K., Franke, H. and Brandt, S., Jamieson, R.A., Beaumont, C., Medvedev, Terrane, Scotland. J. Geol. Soc., 166, 2008. High-grade metamorphism and S. and Nguyen, M.H., 2004. Crustal 545–561. partial melting of granulite facies channel flows: 2 Numerical models with Ort, M.H., Coira, B.L. and Mazzoni, para- and orthogneisses surrounding implications for metamorphism in M.M., 1996. Generation of a crust- the Rogaland complex, Norway. In: the Himalayan-Tibetan orogen. mantle magma mixture: magma sources International Geological Congress 33, J. Geophys. Res., 109, B06407. and contamination at Cerro Panizos, Oslo. Jamieson, R.A., Beaumont, C., Warren, central Andes. Contrib. Miner. Petrol., Elger, K., Oncken, O. and Glodny, J., C.J. and Nguyen, M.H., 2010. The 123, 308–322. 2005. Plateau-style accumulation of Grenville Orogen explained? Applica- Pisarevsky, S.A., Wingate, M.T.D., Powell, deformation: Southern Altiplano. tions and limitations of integrating C.M., Johnson, S. and Evans, D.A.D., Tectonics, 24, TC4020. numerical models with geological and 2003. Models of Rodinia assembly and Elsaesser, L., Drueppel, K. and Gerdes, A., geophysical data. Can. J. Earth Sci., 47, fragmentation. In: Proterozoic East 2008. Metamorphic evolution of sap- 517–539. Gondwana: Supercontinent Assembly and phirine from Rogaland, Nor- Kalsbeek, F., Jepsen, H.F. and Nutman, Breakup (M. Yoshida, B.F. Windley and way: evidence from in-situ La-ICPMS A.P., 2001. From source to S. Dasgupta, eds), pp. 35–55. Geological geochronology of mineral reactions plutons: tracking the origin of ca. 435 Ma Society, London. combined with calculated P-T-x phase S-type granites in the East Greenland Rivers, T., 2012. Upper-crustal orogenic lid diagrams. In: International Geological Caledonian orogen. Lithos, 57, 1–21. and mid-crustal core complexes: signa- Congress 33, Oslo. Karlstrom, K.E., A˚ ha¨ ll, K.-I., Harlan, S.S., ture of a collapsed orogenic plateau in Espurt, N., Funiciello, F., Martinod, J., Williams, M.L., McLelland, J. and Gei- the hinterland of the Grenville Province. Guillaume, B., Regard, V., Faccenna, C. ssman, J.W., 2001. Long-lived (1.8- Can. J. Earth Sci., 49, 1–42. and Brusset, S., 2008. Flat subduction 1.0 Ga) convergent orogen in southern Scha¨ rer, U., Wilmart, E. and Duchesne, dynamics and deformation of the South Laurentia, its extensions to Australia J.-C., 1996. The short duration and American plate: insights from analog and Baltica, and implications for refining anorogenic character of anorthosite modeling. Tectonics, 27. TC3011. Rodinia. Precambr. Res., 111, 5–30. magmatism: U-Pb dating of the Roga- Evans, D.A.D., 2009. The palaeomagneti- Kemp, A.I.S., Hawkesworth, C.J., land complex. Norw. Earth Planet. Sci. cally viable, long-lived and all-inclusive Collins, W.J., Gray, C.M., Blevin, P.L. Lett., 139, 335–350. Rodinia supercontinent reconstruction. and EIMF, 2009. Isotopic evidence for Searle, M.P., Cottle, J.M., Streule, M.J. In: Ancient Orogens and Modern Ana- rapid continental growth in an exten- and Waters, D.J., 2009. Crustal melt logues (J.B. Murphy, J.D. Keppie and sional accretionary orogen: the Tasma- granites and migmatites along the A.J. Hynes, eds), pp. 371–404. Geologi- nides, eastern Australia Earth and Himalaya: melt source, segregation, cal Society, London. Planetary Science. Letters, 284, 455– transport and granite emplacement Fisher, C.M., Loewy, S.L., Miller, C.F., 466. mechanisms. Earth Environ. Sci. Trans. Berquist, P., Van Schmus, W.R., Li, Z.X., Bogdanova, S.V., Collins, A.S., R. Soc. Edinburgh, 100, 219–233. Hatcher, R.D., Wooden, J.L. and Davidson, A., De Waele, B., Ernst, R.E., Sun, S.-s. and McDonough, W.F., 1989. Fullagar, P.D., 2010. Whole-rock Pb and Fitzsimons, I.C.W., Fuck, R.A., Glad- Chemical and isotopic systematics of Sm-Nd isotopic constraints on the kochub, D.P., Jacobs, J., Karlstrom, oceanic basalts: implications for mantle growth of southeastern Laurentia during K.E., Lu, S., Natapov, L.M., Pease, V., composition and processes. In: Magma- Grenvillian orogenesis. Geol. Soc. Am. Pisarevsky, S.A., Thrane, K. and Verni- tism in the Ocean Basins: Geological Bull., 122, 1646–1659. kovsky, V., 2008. Assembly, configura- Society of London Special Publication Frost, B.R., Barnes, C.G., Collins, W.J., tion, and break-up history of Rodinia: a (A.D. Saunders and M.J. Norry, eds), pp. Arculus, R.J., Ellis, D.J. and Frost, C.D., synthesis. Precambr. Res., 160, 179– 313–345. Geological Society, London. 2001. A geochemical classification for 210. Vander Auwera, J., Bogaerts, M., Lie´ geois, granitic rocks. J. Petrol., 42, 2033–2048. Lie´ geois, J.-P., Navez, J., Hertogen, J. and J.-P., Demaiffe, D., Wilmart, E., Bolle, Gower, C.F., Ryan, A.B. and Rivers, T., Black, R., 1998. Contrasting origin of O. and Duchesne, J.-C., 2003. Deriva- 1990. Mid-Proterozoic Laurentia-Balti- post-collisional high-K calc-alkaline and tion of the 1.0-0.9 Ga ferro-potassic A- ca: an overview of its geological evolu- shoshonitic versus alkaline and peralka- type granitoids of southern Norway by tion and a summary of the contributions line granitoids. The use of sliding nor- extreme differentiation from basic mag- made by this volume. In: Mid-Protero- malization. Lithos, 45, 1–28. mas. Precambr. Res., 124, 107–148. zoic Laurentia-Baltica (C.F. Gower, Martinod, J., Husson, L., Roperch, P., Vander Auwera, J., Bolle, O., Bingen, B., T. Rivers and A.B. Ryan, eds), pp. 1–20. Guillaume, B. and Espurt, N., 2010. Lie´ geois, J.-P., Bogaerts, M., Duchesne, Geological Association of Canada, Horizontal subduction zones, conver- J.-C., De Waele, B. and Longhi, J., 2011. Toronto, Special Paper. gence velocity and the building of the Sveconorwegian massif-type anortho- Gower, C.F., Kamo, S. and Krogh, T.E., Andes. Earth Planet. Sci. Lett., 299, 299– sites and related granitoids result from 2008. Indentor tectonism in the eastern 309. post-collisional melting of a continental Grenville Province. Precambr. Res., 167, McQuarrie, N., Horton, B.K., Zandt, G., arc root. Earth-Sci. Rev., 107, 375–397. 201–212. Beck, S. and DeCelles, P.G., 2005. Yin, A. and Harrison, T.M., 2000. Hynes, A. and Rivers, T., 2010. Protracted Lithospheric evolution of the Andean Geologic evolution of the Himalayan- - evidence from the fold-thrust belt, Bolivia, and the origin Tibetan Orogen. Annu. Rev. Earth Grenville Orogen. Can. J. Earth Sci., 47, of the central Andean plateau. Tectono- Planet. Sci., 28, 211–280. 591–620. physics, 399, 15–37. Jackson, J.A., Austrheim, H., McKenzie, Neilson, J.C., Kokelaar, B.P. and Crow- Received 6 March 2012; revised version D. and Priestley, K., 2004. Metastability, ley, Q.G., 2009. Timing, relations and accepted 18 July 2012 mechanical strength, and the support cause of plutonic and volcanic activity

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Supporting Information Data S4. List of ages used to plot should be directed to the correspond- Fig 3. ing author of the article). Additional Supporting Information Please note: Wiley-Blackwell are and Data may be found in the online not responsible for the content or version of this article. functionality of any supporting mate- Data S1. Methods. rials supplied by the authors. Any Data S2. U-Pb zircon data. queries (other than missing material) Data S3. Whole-rock geochemical data.

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