GRANITOID MAGMATISM IN THE NORTH OF THE URALS: U–Pb AGE, EVOLUTION, SOURCES

This work presents the summarization of U–Pb (SIMS, TIMS) zircon dates and petrogeochemical signatures of granitoids of the north of the Urals (Polar, Subpolar, and Northern Urals) obtained over the last decade. Granitе melts were formed from melting of different substrates, highly heterogeneous in composition and age, at all geodynamic stages distinguished in the studied area. Preuralides include island arc–accretionary (735–720 Ma, 670 Ma), collisional (650–520 Ma), and rift-related (520–480 Ma) granitoids. Uralides includes primitive island-arc granitoids (460–429 Ma), mature island-arc granitoids (412–368 Ma), early collisional (360–316 Ma) and late collisional (277–249 Ma) granitoids. As a result, the general trend of variations of oxygen (δ18OZrn, ‰), neodymium (εNd(t)wr), and hafnium (εHf(t)Zrn) isotope compositions identified in time. Mantle isotope compositions (δ18OZrn (+5.6), εNd(t)wr (+1.7), εHf(t)Zrn (+8.7...+10.6)), common for island arc granitoids (Preuralides) are changed by crustal–mantle ones (δ18OZrn (+7.2...+8.5), εNd(t)wr (–4.8...+1.8), εHf(t)Zrn (+2.1 to +13)), typical of collisional granites. According to this, the crustal matter played a significant role during the formation of the latter. The crustal-mantle isotope compositions are changed by the mantle ones, characteristic of rift-related (δ18OZrn (+4.7...+7), εNd(t)wr (+0.7...+5.6), εHf(t)Zrn (–2.04...+12.5)) and island-arc (Uralides; δ18OZrn (+4.2...+5.7), εNd(t)wr (+4.1...+7.4), εHf(t)Zrn (+12...+15.2)) granitoids.


INTRODUCTION
The north of the Urals is geographically divided, from north to south, into the Polar, Subpolar, and Northern Urals and is bounded by Mt. Konstantinov Kamien from the north and Mts. Kosvinsky Kamien and Konzhakovsky Kamien from the south (Fig. 1, a, b).
Granitoids of the north of the Urals have always been the subject of an increased focus, which is reflected in the extensive list of literature [Okhotnikov et al., 1985;Makhlaev, 1996;Goldin et al., 1999;Makhlaev et al., 2005;Kuznetsov et al., 2005а, 2005bKuznetsov et al., 2005а, , 2007Andreichev, 1999Andreichev, , 2010Puchkov, 2010;Melgunov et al., 2010;Soboleva, Udoratina, 2010]. Even recently, their age and formation conditions are the subject of discussion. Due to geological surveying and thematic studies performed in the north of the Urals over the past decade, quite many works present geochronological and isotope-geochemical data on granitoid massifs have been published by authors of the present paper and other researchers. The present report summarizes all these materials.
As evidenced from the previous summaries, differences between granitoids from the Central Uralian and East Uralian megazones in the north of the Urals have long been known.
The differences between granites of the Subpolar Urals in terms of chemical and mineral composition were interpreted to connect with variations in the conditions during their emplacement. Some researchers [Goldin et al., 1981;Shteinberg, Vigorova, 1976] subdivided granites to "dry" and "hydrous" varieties. The dry granites, confined to the western part of the granite distribution area, show that they were crystallized under the hypabyssal conditions. The "hydrous" ones, distributed eastward, are attributed to deeper sources.
the deep structure of the Central Uralian megazone [Berland, 1982]. In terms of density features, the crystalline basement of the latter is close to metamafic rocks in the western zone and granite-gneisses in the eastern one. Massifs, composed of I-type granites, are confined to the west zone; the A-type granites dominate in the east zone.
The typification of granitoids and the combination of petrogeochemical signatures with U-Pb ages brought researchers [Makhlaev, 1996;Soboleva et al., 2005aSoboleva et al., , 2015Andreichev, 2010;Soboleva, Udoratina, 2010] to understanding the evolution of granitoid magmatism in the north of the Urals and accepting the fact that granitoids of different types could often form simultaneously. The recent isotopegeochemical signatures (O Zrn , Sm-Nd wr , Lu-Hf Zrn ) provide insight into the understanding of the primary protoliths of granite melts and their characteristics, as well as the evolution of source rocks and melts in the studied region.
We have taken only U-Pb (SIMS, and TIMS) age of zircons from granitoid massifs into account. Also, our new δ 18 O Zrn ‰, εHf (t)Zrn , and εNd (t)wr data are used. For our work, we have used our and published U-Pb (SIMS, TIMS) isotope ages (210) of zircons from 81 massifs of the north of the Urals, obtained mainly over the past decade using the techniques described in the primary publications. To construct different diagrams, we have used our own and published data on the chemical composition of dated rocks and contents of rare, rare-earth, and trace elements.
The petrogeochemical, geochronological, and isotopegeochemical data on granitoids from the southernmost parts of the Southern Urals, Kanin-Timan Range, and the basement of the Pechora syneclise were not taken into consideration.
This work aims at confirming reference boundaries previously established for the Preuralides and Uralides, analyzing the change of granite melt sources based on petrogeochemical and isotope-geochemical signatures of granitoids. The problems to be considered in the given work are as follows: (1) analysis of the available U-Pb dates of single zircon grains obtained over the past decade, (2) analysis of petrogeochemical features of dated granitoids, (3) analysis of the change of the granite melt sources based on newly obtained isotope-geochemical characteristics (O Zrn , Hf Zrn , Nd whole-rock ), and (4) geodynamic interpretation using U-Pb, petrogeochemical, and isotope-geochemical data on granitoids.

GEOLOGICAL POSITION OF GRANITES IN THE NORTH OF THE URALS
The Uralian collisional orogen in the entire Urals and the north of the Urals, in particular, is composed of the complexes of the East European Craton (Laurussia), island arcs, and fragments of ophiolite complexes [Biske, 2019;Puchkov, 2010]. The Urals is geographically divided from south to north into the Southern, Middle, Northern, Subpolar, and Polar Urals. Structural megazones of the Urals (from west to east) ( Fig. 1, a) are Pre-Urals Foreland basin, West Uralian, Central Uralian, Tagil-Magnitogorsk, East Uralian, and Transuralian megazones. The East Uralian and Transuralian megazones are overlain in the north by deposits of the Siberian Platform. The term East Uralian megazone is often used to refer to complexes (analogs) of the Tagil-Magnitogorsk megazone.
There are no granitoids in the north of the Urals, marking the development of the proper Uralian collisional orogen. The Uralian Orogen ("Uralides") is a young fold belt marking collisional events at the eastern margin of the former Laurussia continent during the Late Carbonaceous and Permian. At this, granitoids, marking the development of the earlier Timan (pre-Uralian) collision, are exposed in the north of the Urals, the Central Uralian megazone, the crystalline basement complexes of the Pechora Plate and Timan. The time of this collision is estimated at 550 Ma . Along with granitoids, the more ancient granite island arc complexes occur in the complexes of the Preuralides.
Preuralides (Timanides) and Uralides, two main structural stages, indicating two separate cycles of tectonic development, are distinguished in the geological structure of the Urals. They were first distinguished in the Southern Urals [Kheraskov, 1948] and extended later to the entire Urals [Kheraskov, Perfiliev, 1963]. Since that time, almost all researchers call them Preuralides (after N.P. Kheraskov) and Uralides. The pre-Ordovician formations are attributed to the lower structural stage; the Uralides, the Hercynian fold system of the Urals, refer to the upper stage. The term Baikalides is often used to designate the Preuralides. In recent years, the terms Protouralides and Timanides have appeared in publications, but they are all synonymous with the priority term Preuralides. Due to this, we have preferred to use the latter.
In the north of the Urals, granite massifs are concentrated in the Central Uralian and East Uralian (Tagil-Magnitogorsk) megazones. The Central Uralian megazone (Central Uralian Uplift, the axial zone of the Urals), located westward of the Main Uralian Fault (MUF), is composed of structural and compositional complexes of the Preuralides. The East Uralian megazone (Tagil-Magnitogorsk), located eastward of the MUF, are composed of complexes of the Uralides.
The detailed description of granitoids (geological-structural position of granitoid massifs, petrographic, petrochemical, geochemical, isotope-geochemical, geochronological characteristics, and the geodynamic interpretations) is given in our publications and publications of other researchers (Suppl. 1; Fig. 1, c; references).

ISOTOPE-GEOCHRONOLOGICAL SIGNATURES
3.1. Preuralides Island arc (735-720 Ma)-accretion (670 Ma) magmatism (island arc formations of the Enganepe uplift within the Central Uralian megazone), granite blocks in the melange zone and Yuznny massif (Suppl. 1; Suppl. 2; Fig. 1, b, c (20-21)). The primitive island arc formations are represented by the most felsic melts of quartz diorites and tonalites, later granodiorites, tonalites, and plagiogranites, calc-alcaline ( Fig. 2, a, b). These rocks belong to the normal petrochemical series in terms of the chemical composition, sometimes with somewhat higher alkalinity (sodium). The substratum is heterogeneous (Fig. 2, c), there is a displacement in the compositional points of the preuralides (island arc, collisional, riftogenic) and uralides (primitive island arc island arc) fields in the peraluminous field, which indicates a significant share of crustal (recycled) material in the formation of granitoids.
These rocks belong to the I-type granites and even to the M-type granites in some parameters . The composition points occupy fields of island-arc granitoids in the discriminant geodynamic diagrams (Fig. 2, g, h). The REE distribution patterns show a wide spread of LREE values, similar HREE values, and the minimum Eu anomaly (Fig. 3, I-а). As usual, spidergrams show the predominance of large-ion-lithophile elements over high-filed-strength elements (Fig. 3, II-a), distinct maximums of K, M-HREE, Y, and minimums of Ti, Sr, bidirectional Nb, Ta, and Pb anomalies. These features are associated with different island arc complexes in the Kharbey block and Enganepe uplift.
Analysis of new U-Pb zircon ages of granitoids (Suppl. 1; see Fig. 1) obtained in recent years confirms this (Fig. 4, a, b, c). The maximum number of dates were obtained for granitoids emplaced during the period of 650-520 Ma; they are characterized by different petrogeochemical signatures.
The petrographic and petrochemical series of these rocks are wide, varying from quartz diorites to leucogranites (see Fig. 2, a). It is difficult to summarize the characteristics of a large number of heterogenous massifs. In general, the field of composition points of this age stage shows a wide variation in contents of SiO 2 and alkalis; rocks belong to normal and alkaline petrochemical series (see Fig. 2, b). The material of different origin was involved in the melting substrate (see Fig. 2, c); composition points lie in the fields of I-, A-, S-granites (see Fig. 2, d, e). Composition points of A-type granites lie near the line between A1-and A2-type granitoids (see Fig. 2, f). In the discriminant geodynamic diagrams, one can see a general swarm of composition points at the intersection of the boundaries of island arc, collision, and intraplate fields (see Fig. 2, g, h).
I-type granites. The chondrite-normalized REE distribution patterns (see Fig. 3, I-b) are characterized by a wide field with equal shoulders (the same contents of LREE and HREE) with bidirectional Eu minimum. Spidergrams show a general predominance of large-ion-lithophile elements over high-filed-strength elements (see Fig. 3, II-b). These granites are characterized by minimum Ti, P, Eu, and Zr values, maximum K, Pb, Tb, Cs, and M-HREE values, and bidirectional Sr, Nb, Cs, and Ce anomalies.
A-type granites. The A-type granites in the chondritenormalized REE distribution patterns are characterized by wide LREE and HREE variations with a distinct bidirectional Eu anomaly (see Fig. 3, I-b). As seen in spidergrams, a predominance of of large-ion-lithophile elements over high-filed-strength elements (see Fig. 3, II-b). These granites are characterized by minimum Nb, Sr, P, and Ti values, maximum Pb, Ta, U, and MREE values, and bidirectional behavior of K, Zr, and Cs.
S-type granites. The chondrite-normalized REE distribution patterns are characterized by similar LREE and HREE values with a distinct deep Eu minimum (see Fig. 3, I-b). The multispectra demonstrate the predominance of large-ionlithophile elements over high-filed-strength elements (see Fig. 3, II-b). The S-type granites are characterized by Eu, Ti, Ta, and P minimal values, insignificant maximums in K, MREE, and Y, and bidirectional behavior of Cs and LREE.
I-type granites. Polar Urals: Kyzygey complex, Left Shchuchye, Kharbey complex (Suppl. 1; Suppl. 2; see Fig. 1, b, c (2, 4-6, 9, 17); Subpolar Urals: Naroda (Suppl. 1; Suppl. 2; see Fig. 1 In terms of petrography and petrochemistry, these granites vary from plagiogranites to leucogranites (see Fig. 2, a). Composition points of rocks of this age stage vary in narrower limits; these rocks belong to rocks of normal and alkaline petrochemical series (see Fig. 2, b). The melting substratum involves both crustal and mantle material (see Fig. 2, c), composition points occupy fields of I-and A-type granites (see Fig. 2, d, e). Composition points of А-type granites occupy a wide area, shifting towards the field of more mantle A1-type granites -granites with minimal participation of crustal material in melting (see Fig. 2, f). A swamp of composition points is shifted towards the field of intraplate formations in the discriminant geodynamic diagrams (see Fig. 2, g, h).
I-type granites. The chondrite-normalized REE distribution patterns (see Fig. 3, I-c) show little REE composition variations with a distinct Eu minimum. Spidergrams show the predominance of large-ion-lithophile elements over high-filed-strength elements (see Fig. 3, II-c). These granites are characterized by small minimums of Ti, P, Eu, Sr, Nb, La, slight maximums of K, Pb, U, M-HREE, and bidirectional Cs anomalies.
A-type granites. The chondrite-normalized REE distribution patterns (see Fig. 3, I-c) show a very wide field of LREE and HREE variations, sometimes with predominance of HREE (typical of metasomatically altered rock varieties of the Taikeu site, Polar Urals), with a strongly pronounced deep Eu minimum. spidergrams show a general predominance of large-ion-lithophile elements over high-filed-strength elements (see Fig. 3, II-c), but with the widest variations in contents of elements. These granites are characterized by minimums of La, P, Eu, Ti, maximums of Th, U, Ta, Pb, HREE, bidirectional behavior of Cs, and an absence of variations in K and Sr.
As seen in Fig. 4, the maximum of formation of rocks with these petrogeochemical characteristics is estimated at 500 Ma.

Uralides
Primitive island arc granites (460-430 Ma) of the East Uralian megazone. As seen in Fig. 4, the I-type granitoids were emplaced in this period.
As a rule, these granitoids are in a narrow range of petrographic compositions: from quartz diorites to tonalites and rarely granites (see Fig. 2, а). Petrochemically, these rocks belong to normal, low-K, Na series (see Fig. 2, b). As a rule, these rocks are derived from a mantle source (see Fig. 2, c). The composition points occupy the I-type granite field (see Fig. 2, d, e). Composition points of these granitoids lie in the field of island arc formations on discriminant geodynamic diagrams (see Fig. 2, g, h).
The chondrite-normalized REE distribution patterns (see Fig. 3, I-d) demonstrate low REE contents and narrow variations of REE contents with bidirectional Eu minimum. The spidergrams show a slight enrichment in large-ionlithophile elements relative to high-filed-strength elements (see Fig. 3, II-d). These rocks are characterized by minimum Ti, P, Eu, Sr, and Nb values, insignificant K maximums, and bidirectional Cs, Rb, Ta, K, Pb, and Zr anomalies.
In terms of mineral composition, rocks are represented by quartz diorites, granodiorites, and granites (see Fig. 2, а). Petrochemically, these rocks belong to normal, low-K, Na series; normal K formations are less common (see Fig. 2, b). The sedimentary (crustal) material (see Fig. 2, c) makes the minimal contribution to the granite melt; composition points of granites lie in the field of I-type granites (see Fig. 2, d, e). In the geodynamic diagrams, composition points of rocks lie in the field of island arc granitoids (see Fig. 2, g, h).
Rocks are characterized by low REE content. The chondrite-normalized REE distribution pattern (see Fig. 3, I-d) shows a non-differentiated type of spectrum close to the basalt one with a practical absence or an indistinct Eu minimum. Multispectra show a predominance of large-ion-lithophile elements over high-filed-strength elements and are characterized by pronounced minimums of Nb, P, Ti, the same distinct maximums of K, Pb, and lower contents of Zr and Gd (see Fig. 3, II-d).
The onset of the collision in the north of the Urals is dated to the Carboniferous, while its termination -to the Late Permian [Puchkov, 2010]. Granitoid massifs emplaced in this period are still unknown, but some dates of zircons from granitoids marked these stages. Based on the latter, we have distinguished two stages: Early collisional stage . In the Polar Urals, this stage is recorded in rims of zircons from the Yanganape and Canyonny massifs of the East Uralian megazone of the Shchuchiya synform and those from granite bodies of the Kharbey block of the Central Uralian megazone and granites of the Ust-Mramorny site.
In the Northern Urals and Central Uralian megazone, the rare-metal phase of granites of the Mankhambo massif include zircons with early collisional ages (336 Ma). Petrochemically, they are high-K granites (see Fig. 2, a, b), belonging to the A-type (see Fig. 2, d, f). Composition points of these granites lie in the field of collisional granites on the discrimination geodynamic diagrams (see Fig. 2, g, h). They are characterized by weakly differentiated REE distribution patterns with a distinct Eu minimum (see Fig. 3, I-a). The primitive mantle-normalized distribution spectra show the predominance of large-ion-lithophile elements, such as Cs, Rb, Ba, and U over high-filed-strength elements, such as Zr and Y (see Fig. 3, II-a).
Late collisional stage (277-249 Ma). The age values of this interval were obtained for some zircons from granites of the Khatalambo-Lapchinsky and Kulemshor massifs of the Central Uralian megazone (Subpolar Urals) and some zircons from granodiorites of the East Uralian megazone (Northern Trans-Urals, Polar Urals). Thus, petrogeochemical signatures of the studied series of granitoids (dated samples) mark different geodynamic regimes of formation in the north of the Urals (Fig. 4, d).
The presence of granitoid massifs of two collisional stages in the north of the Urals is confirmed by dates of detrital zircons from the Paleozoic formations of the West Uralian megazone of the Polar Urals. Thus, the zircon assemblage of the early collisional stage was recognized in the Upper Carboniferous Kechpel Formation, while that of the late collisional stage -in the Lower Permian Gusikhinskaya Formation [Kuznetsov et al.,2013].

ISOTOPE-GEOCHEMICAL SIGNATURES
We have obtained O, Hf, and Nd isotope compositions for the nearly third part of all massifs, which also have the U-Pb ages (Suppl. 1; Fig. 5, a, b, c).

Oxygen isotope composition.
Based on the genetic classification, granitoids, close in composition to I-, S-, А-types and, to a lesser extent, M-type, are distinguished among complexes of the Preuralides. According to the classification [Chappell, White, 1974;Whalen et al., 1987], the I-type granitoids are typical of the Uralide complexes.
Subpolar and Northern Urals. Preuralides. Regardless of the granite composition, δ 18 O value in zircons varies from +7.10 to +8.51 ‰ (low values are rarely noted), indicating the crystallization of zircons from crustal melt and a possible presence of subducted sediments and seawater in the substrate [Valley et al., 1998]. The lowest values (+7.10 ‰) in this group of granitoids are characteristic of zircons from quartz diorites of the Perevalny massif (625±8 Ma), which are intermediate in composition between I-and M-type granites (Suppl. 1; see Fig. 1, b, c, 43-1).
Granitoids of the final post-orogenic evolution stage of the Preuralides and practically synchronously emplaced granitoids of the pre-rifting and early rifting stages of the Uralides are combined into the group of younger granitoids since there are no clear criteria to discriminate them. Granites and leucogranites, belonging to the I-and mainly A-type varieties, dominate in this group. The granitoids of this group are characterized by lower δ 18 О values in zircons, up to very low ones. Thus, δ 18 О in zircons from I-type granitoids varies from +6.22 to +7.33 ‰, reaching the maximum in leucogranites of the Ilyaiz massif. Zircons from A-type granites are characterized by even lower δ 18 О values from +3.27 to +6.86 ‰. Abnormally low δ 18 О values were measured in zircons from granites of the Mankhambo massif (+4.7 ‰), Kulemshor massif (+3.27 ‰), and the Lemvinsky massif (out of consideration here) (+3.47-+3.79 ‰) [Soboleva et al., 2015]. These values are significantly lower than typical mantle values (+5.3±0.6 ‰ [Valley et al., 1998].

Nd isotope composition
Nd isotope composition was obtained for whole-rock compositions of 11 massifs. All these massifs are characterized by different negative and positive values (Suppl. 1; Fig. 5, b).
The obtained results indicate an essential contribution of the crustal material at the generation of primary granite melts.
Polar Urals. Granitoids of the rift-related stage. The εNd values were obtained for A-type granites of the Ochety and Syadatayakha massifs (+5.6 and +2.6; mantle values), the northern part of the Gerdiz and Ingilor massifs (+0.7 and +0.6, crustal-mantle values). It is also confirmed by the position of composition points of granites of the Gerdiz and Ingilorsky massifs in field A2 of the A1-A2 discriminant diagram, where the contribution of a mantle component is insignificant. The points of granites of the Syadatayakha massif lie in the field A1 with a significant admixture of a mantle component (see Fig. 2, f). The position of the composition point of the Ochety massif with a mantle εNd value in the А2 field needs to be understood.

Hf isotope composition
The relative stability of the Hf isotope system in zircons makes Hf isotopes an important tool for studying the age of a granite melt source and isotope evolution of different rocks. Negative values indicate the participation of the recycled crystal material in the granite melts. In contrast, the positive values indicate the mantle component's role [Amelin et al., 1999;Fujimaki, 1986;Griffin et al., 2002]. We have first studied the Hf isotope composition of zircons from granitoids and have calculated the model ages of massifs of the Polar, Subpolar, and Northern Urals (Suppl. 1; Fig. 5, c). Polar Urals, Central Uralian megazone, island arc stage. Zircons from plagiogranites (719 Ma, island arc geochemical signatures (I-type)) from the serpentinite mélange zone of the Enganepe Ridge have positive (mantle) εHf (T) values, varying in a narrow range of +8.7...+10.6. The model age of the granite-producing protolith is 1.2-1.1 Ga.
I-type granites of the collisional stage of the southern part of the Gerdiz massif (573 Ma) are characterized by wide variations in crustal-mantle Hf isotope composition (εHf (T) , from -5.84 to +7.52). This is due to the presence of different-aged zircons in the dated zircon association. The model age T DM2 of a protolith is 1.72-0.9 Ga. The Longotyugan, Taikeu, and Neudachny massifs (605-560 Ma), which have collisional geochemical signatures and belong to the A-type granites, are characterized by mantle εHf (T) values (+6-+13) and similar model ages (T DM2 : 1.4-0.76 Ga).
Most of the zircons from granitoids of the ore zone of massifs of the central part of the Central Uralian megazone (Longotyugan, Taikeu, Ust-Mramorny) have different model ages and high εHf (T) positive values varying from +4.1 to +15.1 (Suppl. 1). All this indicates the influence of a mantle source.
Polar Urals, East Uralian megazone. The age data were obtained only for island arc mature granitoids (granitoids of the Sobsky massif and oligoclasite bodies in ophiolites of the Rai-Iz massif). The εHf (T) values in granitoids of the Sob massif (+11.9...+14.7) indicate the mantle (isotope immature) source of the protolith. The calculated model age of the protolith corresponds practically to the age of the origin of granitoids (0.72-0.47 Ga). The close εHf (T) values (+13.5…+15.2) were obtained for diorites of the Kongor complex (Dioritovy massif), T DM2 -0.50-0.38 Ga .
The εHf (T) values for oligoclasites of similar age (382±2 Ma), developed in the Rai-Iz ophiolites, vary widely from -11.2 to +11.4. We suggest that these values are determined by the effect of a subduction fluid on the mantle wedge peridotites during the formation of oligoclasite veins [Meng et al., 2018].
Subpolar and Northern Urals. Central Uralian megazone, collisional stage. Zircons of granites of the Vangyr massif (I-type) and Nyarta complex (S-type) were studied. The εHf( T ) values in granites of the Vangyr massif varying in a range from +1.97 to +6.82 indicate an admixture of the mantle component in the protolith; the model age is 1.76-1.32 Ga. The crustal-mantle εHf (T) values are typical of granitic gneisses of the Nyarta complex (Suppl. 1; see Fig. 1, b, c (45)), which is also, apparently, associated with the different ages of zircons. For the age of 619 Ma, interpreted as the inherited one, the εHf (T) values are in a range of -2.09...+1.76, which indicates the presence of recycled crustal material during the formation of this-age zircons. The model age is 1.48-1.29 Ga. The Hf isotope composition of zircons with an age of 518 Ma, considered as the generation time of granitoid magmas, varies in the range +3.58... +5.16; the model age is 1.11-1.03 Ga.
Central Uralian megazone, rift-related stage. The A-type granitoids of the Kozhim massif (Suppl. 1; see Fig. 1, b, c (40)) are also characterized by crustal-mantle εHf (T) values. Zircons are of different ages (485 and 619 Ma). The εHf (T) values in zircons with an inherited age of 619 Ma vary from +0.87 to +1.41; a granitoid source is crustal-mantle (hybrid, mixed). The model age of the protolith is 1.33-1.31 Ga. Based on studying younger zircons, we consider this age as the time of emplacements of Kozhim massif's granitoids. The εHf (T) values of these zircons are from +2.50 to +3.42 (mantle); the model age is 1.15-1.07 Ga.

DISCUSSION AND CONCLUSIONS
The granitoid magmatism in the north of the Uralian collisional orogen is represented by products of two large geodynamic stages -Timanides-Preuralides and Uralides. The every stage is characterized by the emplacement of granitoid melts of different petrogeochemical types, which often occur in the same massifs.
Granitoids of the Central Uralian megazone mark the Preuralide (Timanide) evolution of the active margin and Baltica-Arctida collision . The Preuralides are characterized by the change of the island arc magmatism (735-720 Ma; generation of I-type (M-type) granitoids) to the accretionary magmatism (670 Ma, I-type granitoids), and, then, to the collisional (620-520 Ma; simultaneous generation of A-, I -, S-type granitoid melts) and the rift-related magmatism (520-480 Ma; mainly, the generation of A-type granites).
The U-Pb zircon age distribution histograms constructed separately for granitoids of the Polar, Subpolar, and Northern Urals (see Fig. 4) show an insignificant shift of the peak of collisional processes, namely, the peak of development of the Protouralide (Timanide) Orogen and its subsequent break-up.
According to the geochronological data available, this peak in the Polar Urals is estimated to be at 525 Ma. In the Subpolar Urals, there were two peaks of 625-600 Ma and 550-525 Ma, while in the Northern Urals the peak was at 550-500 Ma. When compiling an integrated U-Pb zircon age distribution histogram for the granitoids of the north of the Urals, the only peak of 550-525 Ma is distinguished.
Thus, the development of the Protouralides-Timanides was a relatively long-term process, lasting from 620 to 520 Ma with a peak at 550 Ma. Granitoids of all types (M, S, I, A) lying in this age interval were recognized in the north of the Urals. After the turn of 520 Ma, only I-and A-type granites, marking the rift-related stage and the onset of a new tectonic cycle (properly, Uralian), are recognized. The latter is terminated with the formation of the Urals. Composition points of non-collisional I-and A-type granites are confined to the fields of intraplate formations and indicate their origin from a mantle source. The I-type granites, formed already in the Uralian time, are characterized by typical is land arc characteristics.
The isotope analysis performed has shown that O and Hf isotope contents in zircons and the whole-rock Nd content show the variability in the maturity of the protolith of granitoids from the Northern Urals to Polar Urals. The signatures of the most mature recycled material are recorded in the granitoids of the Preuralides of the Northern and Subpolar Urals: δ 18 О, from +7.10 to +8.51 ‰, εNd=-4.8 to -0.3, εHf (T) =-3.35 to -1.95 (Suppl. 1). The granitoids of the Preuralides of the Polar Urals are characterized by the presence of mantle-derived components and a more moderate contribution of the crustal material to the primary melts: δ 18 О, from +4.7 to +6.22 ‰, εNd=+0.6…+5.6, εHf (T) + +2.15…+15.1 (Suppl. 1). In general, the model age (Т DM2 ) of the protolith of granitoids of the Preuralides of the Subpolar (1.76-1.03 Ga) and Northern (2.09-1.11 Ga) Urals is older compared to that of granitoids of the Polar Urals (1.48-0.64 Ga).
Thus, almost all the obtained data (δ 18 О zrn , εHf (t)Zrn , εNd (t)wr ) show a significant contribution of the mantle component to the formation of granitoids of various types in the north of the Urals.

ACKNOWLEDGEMENTS
The authors are grateful to M.V. Savatenkov (IGGD, Saint Petersburg) for the studies of the Sm-Nd system of granitoids, V.F. Posokhov (GIN SB RAS Ulan-Ude) for studying the isotopic composition of oxygen in zircons of granitoids M.A. Coble (Stanford University, USA) for the possibility of conducting U-Pb research, as well as F. Meng and J. Geng (China Academy of Sciences, Beijing and the Tianjin Institute of Geology and Mineral Resources, China) for the opportunity the possibility of studying the Lu-Hf zircon system.