Quantifying Arabia–Eurasia Convergence Accommodated in the Greater Caucasus by Paleomagnetic Reconstruction ∗ A

Earth and Planetary Science Letters 482 (2018) 454–469

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Earth and Planetary Science Letters

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Quantifying Arabia–Eurasia convergence accommodated in the Greater Caucasus by paleomagnetic reconstruction ∗ A. van der Boon a, , D.J.J. van Hinsbergen a, M. Rezaeian b, D. Gürer a, M. Honarmand b, D. Pastor-Galán a,c, W. Krijgsman a, C.G. Langereis a a Utrecht University, The Netherlands b Institute for Advanced Studies in Basic Sciences, Zanjan, Iran c Center for Northeast Asian Studies, Tohoku University, Japan a r t i c l e i n f o a b s t r a c t

Article history: Since the late Eocene, convergence and subsequent collision between Arabia and Eurasia was accommo- Received 23 June 2017 dated both in the overriding Eurasian plate forming the Greater Caucasus orogen and the Iranian plateau, Received in revised form 20 September and by subduction and accretion of the Neotethys and Arabian margin forming the East Anatolian plateau 2017 and the Zagros. To quantify how much Arabia–Eurasia convergence was accommodated in the Greater Accepted 9 November 2017 Caucasus region, we here provide new paleomagnetic results from 97 volcanic sites (∼500 samples) in Available online xxxx ∼ ◦ Editor: A. Yin the Talysh Mountains of NW Iran, that show 15 net clockwise rotation relative to Eurasia since the Eocene. We apply a first-order kinematic restoration of the northward convex orocline that formed to Keywords: the south of the Greater Caucasus, integrating our new data with previously published constraints on tectonic rotations rotations of the Eastern Pontides and Lesser Caucasus. This suggests that north of the Talysh ∼120 km paleomagnetism of convergence must have been accommodated. North of the Eastern Pontides and Lesser Caucasus orocline this is significantly more: 200–280 km. Our reconstruction independently confirms previous Caucasus Eocene volcanics convergence estimates. Moreover, we show for the first time a sharp contrast of convergence between Iran the Lesser Caucasus and the Talysh. This implies that the ancient Paleozoic–Mesozoic transform plate Greater Caucasus boundary, preserved between the Iranian and East-Anatolian plateaus, was likely reactivated as a right- lateral transform fault since late Eocene time. © 2017 Elsevier B.V. All rights reserved.

1. Introduction The Greater Caucasus mountain range, between the Black Sea and the Caspian Sea, is the world’s second largest active oro- Quantification of how convergence is accommodated in conti- gen in a continental collision setting (Mumladze et al., 2015). nental lithosphere in response to plate collisions – in this case Its relatively short length (∼1100 km) and location within the the Arabia–Eurasia collision – is crucial for understanding the oro- overriding Eurasian part of the plate boundary zone, >350 km genic processes and related paleogeographic evolution such as the north of the suture with Arabia, make it an uncommon orogen. closure of marine gateways. However, there is often a deficit be- It is thought to have formed since the late Eocene (∼35 Ma) tween estimates of crustal shortening and reconstructions of the through inversion of a Mesozoic back-arc basin during Arabia– amount of convergence from the plate circuit, as e.g. argued for in Eurasia convergence and collision (e.g., Adamia et al., 2011a). The the India–Asia (Van Hinsbergen et al., 2012), or Iberia–Europe col- formation of the Greater Caucasus fold-thrust belt demonstrates lision (Vissers et al., 2016). Such a mismatch between shortening that some of the 800–900 km of ∼N–S Arabia–Eurasia conver- and convergence has recently also been postulated for the Greater gence that occurred since 35 Ma along the strike of the Caucasus Caucasus on basis of seismological and sediment provenance data (McQuarrie and van Hinsbergen, 2013), was accommodated within (Cowgill et al., 2016). Demonstrating such a mismatch, however, the Eurasian part of the plate boundary zone. There is considerable requires firm constraints on convergence, which is often contro- debate on the timing of shortening and uplift of the Greater Cau- versial. casus Mountains, with estimates ranging from Eocene–Oligocene (Vincent et al., 2016)to Miocene (Forte et al., 2014). Forte et * Corresponding author. al. (2014) recognized that the Greater Caucasus is made up of E-mail address: [email protected] (A. van der Boon). several distinct structural zones which may reflect lateral differ- https://doi.org/10.1016/j.epsl.2017.11.025 0012-821X/© 2017 Elsevier B.V. All rights reserved. A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 455 ences in amount of accommodated shortening and convergence crust-derived accretionary prism formed that underlies most of along the mountain range. In any case, the geological and seis- the east Anatolian plateau. The Turkish and Iranian systems were mological estimate of Greater Caucasus shortening and subduction separated by a plate boundary since the Permian (Stampfli and may have been 130 to as much as 400 km (Cowgill et al., 2016; Borel, 2002), probably in the form of a major transform fault sys- Ershov et al., 2003). The remainder of Arabia–Eurasia convergence tem. Eastern Mediterranean paleogeographic reconstructions sug- then has to be accommodated by subduction within or below the gest that this transform may have been reactivated since the early East Anatolian and Iranian plateaus. Eocene (visualized in Barrier et al., 2008). The Arax valley fault, Constraining how this convergence was partitioned is partic- on the border between Armenia, Iran and Azerbaijan (Jackson and ularly complex due to the general absence of detailed structural Mckenzie, 1983)may be a remnant of this ancient plate boundary geologic constraints on Caucasus shortening. Moreover, geologi- (Fig. 1). cally recorded shortening may underestimate the total amount of The Lesser Caucasus region is located to the south of the convergence if wholesale lithospheric subduction occurred without Greater Caucasus, and is formed by volcanic arc material of Juras- accretion. Paleomagnetic inclinations may be used to determine sic to Eocene age, which connects to the Pontides in the west and paleolatitudinal convergence if convergence is larger than paleo- the Talysh in the east during Eocene volcanism (e.g. Adamia et al., ◦ magnetic error bars of typically some 5 (∼500 km), which is 2011b). This region is bordered from the Gondwana-derived South unlikely in the Caucasus case. Cowgill et al. (2016) recently sug- Armenian block to the south by the ophiolitic Sevan-Akera suture gested that higher convergence in the Greater Caucasus than in the (e.g. Rolland et al., 2012; Sosson et al., 2010). neighboring Black Sea and Caspian Sea regions led to the forma- As there are no tectonic maps of the entire studied region, we tion of the Pontide–Lesser Caucasus–Talysh orocline, which extends compiled a new tectonic map (Fig. 1) from the maps of Adamia et from the eastern Pontides (NE Turkey), through the Lesser Cauca- al. (2011b); Sengör¸ et al. (2003); Zanchetta et al. (2009), and we sus (e.g. Bazhenov and Burtman, 2002 and Meijers et al., 2015 and added faults from Dilek and Altunkaynak (2010) and Solaymani references therein). Here, we therefore explore a novel quantita- Azad et al. (2011). All maps were georeferenced, overlain on top tive geometrical constraint on the amount of Arabia–Eurasia con- of each other and subsequently checked using a digital elevation vergence that was accommodated in the Greater Caucasus region model in discerning tectonic regions. since the late Eocene by paleomagnetically restoring the vertical axis rotations accommodated during the formation of this orocline, 2.2. Geology of the Talysh which we extend towards the Talysh Mountains of Iran (Fig. 1). We use paleomagnetic estimates of net post-Eocene rotation from the The geology of the Talysh and Alborz consists of Precambrian limbs of this orocline to restore the convergence accommodated in up to Quaternary rocks, with abundant Eocene volcanic rocks. The the Greater Caucasus. Large datasets are available from the western Precambrian and Cambrian make up around 3.5 km and consist limb in Turkey (Hisarlı, 2011), as well as from the central, Lesser mostly of sandstone and dolomite. Silurian and Ordovician units Caucasus segment (Meijers et al., 2015). In the western part of the consist of limestone and some basic volcanic rocks. The Devo- Alborz mountains, data were collected by Cifelli et al. (2015). We nian is characterized by deposition of limestone, with an uncon- here provide new paleomagnetic constraints on the amount of ro- formity separating it from the underlying Silurian. Post-Silurian tation of the eastern limb of the orocline, in the Talysh Mountains basic volcanic rocks are covered by Permo-Carboniferous limestone of Iran. Then, we develop a first-order kinematic restoration of the and lower Carboniferous andesite. The Talysh contains remnants of orocline to constrain the minimum amount of northward motion an Upper Paleozoic ophiolite belt, which is related to closure of of the Lesser Caucasus relative to the Black Sea and Caspian Sea a Hercynian ocean. The Triassic–Jurassic consists of shales, sand- regions since the Eocene. We use this reconstruction to quantify stones and conglomerates, and is around 4km thick. During the how convergence was partitioned over the Caucasus orogen and Upper Jurassic and Cretaceous, shallow marine limestones were plateaus to the south. deposited in the Talysh and Alborz, which make up around 600 meters (Berberian and King, 1981; Zanchi et al., 2006). Some Creta- 2. Geological setting ceous volcanic rocks with a within-plate signature are also present in the Central Alborz (Doroozi et al., 2016). The Paleogene in the 2.1. Regional geology Alborz consists of the Fajan formation, comprising up to 200 meters of continental conglomerates. This formation is covered by The Caucasus orogen is located along the southern fringes of Paleocene–middle Eocene nummulitic limestones of the Ziarat for- the Scythian platform of Eurasia. To the south are a series of mation (100–300 m thick). The top of this formation is of Lute- accreted Gondwana-derived continental blocks that collided with tian age (middle Eocene) in the Alborz, while further east, in the Eurasia upon closure of the Paleotethys and Neotethys oceans in Kopeh Dagh, it extends into the Priabonian (late Eocene) (Gravand Paleozoic to Cenozoic times (e.g. Barrier et al., 2008). In Iran, and Golgir, 2014). After the Lutetian, a flare-up of volcanism led Gondwana-derived ‘Cimmerian’ blocks collided with Eurasia in the to deposition of the Karaj formation, which is up to 9km thick Late Triassic, closing the Paleotethys ocean after which they were (Verdel et al., 2011), and has a continental arc geochemical signa- shortened in the Neogene during Arabia–Eurasia collision by up to ture (van der Boon et al., 2015). During the Oligocene, compres- ∼175 km (McQuarrie and van Hinsbergen, 2013; Mouthereau et sion in the region led to uplift and erosion, causing deposition al., 2012). NW Iran consists of at least two Cimmerian blocks, the of coarse-grained clastic sedimentary rocks (Morley et al., 2009; Sanandaj-Sirjan block and the Alborz block. Neotethys subduction Vincent et al., 2005). below the Iranian Cimmerian blocks occurred from the Jurassic un- There are many large faults present in the region, although til the final collision of Arabia with Eurasia (Agard et al., 2011). these are relatively unstudied. Both thrust faults and strike-slip Present shortening estimates of the Iranian plateau and the Za- faults are present in the region, with strike-slip faults showing gros mountains suggest that collision must have been underway left lateral motion (e.g. Jackson et al., 2002). The faults in the Al- by 20 Ma, and may have started around 27–28 Ma (McQuarrie borz and the Talysh are different from each other, with faults in and van Hinsbergen, 2013 and references therein). In Turkey, the the Talysh having nearly flat fault planes on which thrusting oc- tectonic history is different. In the west, at least two Gondwana- curs. The motion along faults is disputed. For example, Jackson derived continental fragments collided with Eurasia (Pontides and et al. (2002) interpret the Astara fault as a thrust (Fig. 2), while Anatolide-Taurides), while in eastern Turkey a long-lived, oceanic on 1:100.000 series geologic maps (Geologic Survey of Iran), it is 456 A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469

Fig. 1. Simplified geological map of the Caucasus, Talysh and Alborz region and the main tectonic units (modified after: Adamia et al., 2011b;Sengör ¸ et al., 2003; Zanchetta et al., 2009). Faults are after Dilek and Altunkaynak, 2010; Solaymani Azad et al., 2011. drawn as a strike-slip fault. Faults as shown in Fig. 2 are compiled with a dispersion parameter k often higher than 100. In this study, from 1:100.000 series geologic maps (Geologic Survey of Iran), and we follow the slightly more lenient criterion of k > 50 (Biggin et the studies of Jackson et al. (2002) and Rezaeian et al. (2012), with al., 2008). Common paleomagnetic statistics typically require 5–7 the nature of the faults drawn tentatively. samples per lava flow to give a good estimate of k. However, due to the extremely hard lithology of the volcanic rocks in most sites 3. Methods and the long time it took to drill a single core (up to 15 min), we compromised by taking less samples per flow (minimum of 3) but Sampling was carried out in 2014, along the belt of Eocene vol- sampling more lava flows per locality. More than 500 standard pa- canics which forms the Talysh mountain range in NW Iran, from leomagnetic samples (25 mm diameter cores) were drilled using a the border with Azerbaijan in the north, to the south-east until gasoline-powered drill; the cores were cut in the laboratory into Kakajin. In total, 97 sites of Eocene rocks were sampled which standard (22 mm) specimens. Samples with a high intensity nat- we logically grouped into 11 localities (Fig. 2). By far the major- ural remanent magnetization and exceeding the dynamic range of ity of rocks were lava flows and volcaniclastic rocks, ranging in the cryogenic magnetometer were subsequently cut in half. composition from basaltic lavas and andesites to tuff breccias and The specimens were subjected to thermal and/or alternating ◦ ignimbrites. From the 97 sites, only 9 sites were taken in sedimen- field (AF) demagnetization. Temperature increments of 20–80 C tary rocks, mostly fine-grained volcaniclastic and tuffaceous sedi- were applied to thermally demagnetize the samples in a shielded ◦ mentary rocks; the remaining 88 sites were drilled in lava flows, ASC TD48-SC oven, up to a maximum temperature of 680 C. De- where each single flow is designated one site. Lava flows typically magnetization steps ranging 5–100 mT with field steps of 5 or record spot readings of the magnetic field and tend to give con- 10 mT were applied for AF demagnetization. The magnetization centrated (low dispersion, high k value) directional distributions, after each step was measured on a 2G Enterprise horizontal cryo- A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 457

Fig. 2. Map of the Talysh with sampled paleomagnetic sites and localities and stratigraphic column (modiﬁed after Berberian and King, 1981).

◦ genic magnetometer equipped with three DC SQUIDS (noise level creasing magnetization up to temperatures of 550–580 C, indica- − 3 × 10 12 Am2) for thermal demagnetization, or with a robo- tive of (Ti-poor) magnetite. Some samples required higher tem- − ◦ tized 2G DC-SQUID magnetometer (dynamic range 3 × 10 12 to peratures up to 680 C, indicative of the presence of hematite. − 5 × 10 5 Am2) for AF demagnetization. Most samples show de- The results were analyzed using orthogonal vector diagrams and 458 A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 the characteristic remanent magnetization (ChRM) directions were extrusive volcanic rock. Although it shows a clockwise rotation af- determined using principal components analysis. Great circle anal- ter tilt correction, the inclination is anomalously low. As we only ysis was performed on samples that had components that were have sampled one flow, we are not able to determine the average not entirely removed after demagnetization, or became viscous or direction from this locality and dismiss it for further interpretation. spurious at higher temperatures. The mean directions were deter- ◦ Border mined using standard Fisher statistics, and a 45 cut-off was used. Per site (flow) the 95% cone of confidence (α95) was determined, The Border locality consists of 7 sites, of which 2 are sedimen- while for a sequence of flows errors in declination (Dx) and incli- tary rocks. Sites IR100, 101 and 102 show a small cluster with nation (Ix) were calculated from the A95 of the VGP distribution. different directions than site IR103-106. They show no rotation in We used the criteria of Deenen et al. (2011), which means we de- tectonic coordinates, versus a rotation of about 20 degrees clock- termine A95 of the VGP distribution, and require the value to be- wise in geographic coordinates, so it is unlikely that these sites tween the N-dependent values of A95min and A95max to represent have a present day field overprint. Also, they have shallow inclina- paleosecular variation (PSV). We used the web portal Paleomag- tions in geographic coordinates (NOTC), versus steeper inclinations netism.org for the interpretation of demagnetization diagrams and in tectonic coordinates (TC). We have inverted IR104 to normal po- for assessing the statistical properties of directional distributions larity (but with a negative inclination), while IR103 and IR106 have ◦ (all appropriate references are given in the portal). This is an open anomalous south-down directions and fall outside the 45 cut-off. source and platform independent on-line application (Koymans et North Talysh al., 2016). We provide all data and interpretations in the online supplementary information in files that can simply be imported The North Talysh locality consists of 26 sites, of both normal into the portal. Where possible, bedding planes were measured in and reversed polarity. Inclinations are generally shallow, and be- the field, and we give our paleomagnetic results both before tilt come steeper after tectonic correction (TC). If we invert all re- correction (geographic coordinates, NOTC) and after tilt correction versed sites to normal, no sites are rejected on the basis of the ◦ (tectonic coordinates, TC). However, for volcanic rocks, often no 45 cut-off, but we reject 7 sites on the basis of too high inter- clear bedding could be observed. In these cases we estimated bed- nal dispersion (k < 50, Table 1), although the means of N = 26 and = ding from geological maps (1:100.000 series and 1:250.000 series, N 19 are identical within errors (Dx, Ix). The mean declina- Geologic Survey of Iran) and/or Google Earth. All drilling directions tion of the remaining sites (N = 19) does not significantly change ◦ ◦ ◦ and bedding were corrected for a declination of 4.6 according to upon tilt correction (from ∼29 to ∼30 ), while the mean incli- ◦ ◦ the International Geomagnetic Reference Field (IGRF). nation increases significantly (from ∼23 to ∼37 ). A95 values are All demagnetization diagrams with interpreted directions are within the required A95min–A95max envelope and hence the local- included in the appendix as Site.dir files. These files can be opened ity likely represents PSV, although a reversal test is negative. in the interpretation portal of Paleomagnetism.org under Advanced Kajal Options, and Import Application Save. All individual sites are imported into the Statistics portal, where they can be combined, The Kajal locality consists of 6 sites and has only normal direc- viewed and assessed per locality or in any other combination de- tions. IR98 is an Oligocene trachybasalt/trachyandesite (1:100.000 sired. We provide all sites per locality as Locality.pmag files, which series geologic maps, Geologic Survey of Iran). Directions however are very similar to the other sites of reported Eocene age. can be opened in the statistics portal of Paleomagnetism.org, in a ◦ The mean declination does not change upon tilt correction (∼28 ), way identical to the Interpretation portal. ◦ ◦ while the mean inclination decreases (from ∼50 to ∼39 ) but = ◦ 4. Results still within error since Ix 13.1 after tilt correction. Meshkin Sites of Eocene rocks that were geographically close together The Meshkin locality consists of 10 sites all sites having normal were grouped into 11 localities (Fig. 2). Demagnetization behav- polarities. Two sites (IR59 and IR63) were rejected (k < 50, Table 1) ior of the samples is mostly straightforward, with no significant ◦ although all sites fall within the 45 cut-off. The mean declination low coercivity/low temperature components. Representative exam- ◦ ◦ changes upon tilt correction (from ∼20 to ∼29 ), while the mean ples of demagnetization diagrams and site averages are shown in ◦ ◦ ◦ inclination increases (from ∼40 to ∼52 ). A95 values are within Fig. 3. In general, the component above 20 mT or above 200 C the required A95 –A95 envelope. was interpreted. Samples showing partially unresolved components min max after demagnetization were interpreted using great-circle analy- Zanjan sis (McFadden and McElhinny, 1988). For these samples, often the ◦ The Zanjan locality consists of 3 sites. All sites show normal steps below 20 mT or 200 C were taken into account. As a rule, polarity and have very low inclinations in geographic coordinates we accepted only sites where the number of setpoints (i.e. di- ◦ ◦ that become steeper in tectonic coordinates (from ∼31 to ∼41 ). rectly interpreted ChRM components) was equal or greater than The mean declination changes slightly upon tilt correction (from the number of great circle solutions (Fig. 3G). If there were not ◦ ◦ ∼11 to ∼17 ). One site (IR18) has k = 42 but this is a realistic enough setpoints, we combined two nearby sites with a CTMD to value for (tuffaceous) sedimentary rocks. obtain enough set points to perform the great-circle analysis. Re- sults of all sites per locality are shown in Fig. 4. Zaaker The Zaaker locality consists of 9 sites. Sites IR69 and IR73 show Astara ◦ an anomalous direction and fall outside the 45 cut-off. In addi- In the Astara locality there are only two sites, CH88 and IR04. tion, IR73 is not fully demagnetized at 100 mT, caused by the CH88 is the site that was dated in the study of Chiu et al. (2013). presence of hematite, but samples are fully thermally demagne- ◦ We were unable to find the basalt that was mentioned in the study tized at a temperature of 680 C. IR67 and IR68 show anomalous and sampled a tuff breccia. Paleomagnetic results of this site only declinations but have very low k values and are rejected, while also ◦ show low temperature components. Above ∼30 mT or 300 C, the IR20 and IR71 have k < 50. The sites show greater dispersion af- samples show ‘spaghetti plot’ behavior. This site is therefore omit- ter tilt correction, providing a negative fold test. Hence, only three ted. The other site that was sampled at this locality, IR04, is an sites of this locality are left that meet our criteria. A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 459

Fig. 3. Examples of paleomagnetic results and interpreted directions. Zijderveld diagrams (Figs. 3A, 3C and 3E), equal area projections of directions of one site (Figs. 3B, 3D and 3G), great-circle interpretation of a sample (Fig. 3F) and great-circle solutions and directions of one site (Fig. 3G). 460 A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469

Fig. 4. Equal area projections of site means per locality. NOTC is before tilt correction (geographical coordinates), TC is after tilt correction (tectonic coordinates).

Valayesh with the exception of IR89. IR91 and IR92 are located close to each other and both show anomalous directions that are rejected by the The Valayesh locality consists of 9 sites, in which both normal ◦ 45 cut-off. IR87 is rejected because of k < 50 (Table 1). Of the re- and reversed polarities are present. IR22 (k = 13) and IR50 (k = 7) maining 7 sites, the mean inclination does not change within error are rejected because of both low k values and falling outside the ◦ ◦ ◦ upon tilt correction (from ∼28 to ∼31 ). The mean declination 45 cut-off. Also IR54 and IR56 are rejected because k < 50 (Ta- ◦ ◦ changes slightly upon tilt correction (from ∼50 to ∼43 ), and this ble 1). Both in geographic and tectonic coordinates the declina- ◦ ◦ locality shows therefore a larger than average rotation, compared tions show – within error (resp. D = 11.4 and D = 21.9 )– x x to most other sites. no significant rotation with respect to North. Inclinations become ◦ ◦ steeper upon tectonic correction (from ∼49 to ∼64 ). 5. Discussion Takestan 5.1. Paleomagnetic directions The Takestan locality consists of 5 sites. Both normal and reversed polarities are observed. Site IR23 is rejected (k < 50, Ta- In general, the results of our sites are good to excellent, most ble 1), and the remaining sites are very scattered. The mean dec- sites (80%) met our criterion of low dispersion of the distribution lination in geographic coordinates shows no significant rotation (k > 50), denoting that these are good recorders of the geomag- with respect to North, similar to Valayesh. Upon tilt correction the netic field. Low values (k < 50) are typically expected for sedimen- scatter increases (A95 > A95max) and the directional distribution is tary rocks, and some 10% of our sites were in volcaniclastic rocks. meaningless. These sites are expected to give low k values if they are epiclas- Molla Ali tic, i.e. deposited through reworking of volcanic material, relatively slowly and at low temperatures. In other cases, where volcaniclas- The Molla Ali locality consists of 9 sites, all showing normal tic deposits such as ignimbrites, debris avalanches, hyalotuffs or polarities and all sites having high k values. Like Valayesh (and peperites are present, deposition can take place within minutes to Takestan in geographic coordinates), declinations show no signifi- hours, at high temperatures. Considering the unusually high (up to cant rotation with respect to North, both before and after tilt cor- k = 300) values of our sedimentary rock sites, it is likely that our rection, while inclinations become steeper upon correction (from sampling mainly included pyroclastic rocks that were deposited ◦ ◦ ∼45 to ∼51 ). After tilt correction, only site IR79 falls outside of at higher temperatures. Indeed, some geologic maps mention the ◦ the 45 cut-off. presence of units containing autoclastic and hyaloclastic breccias and tuffs and pyroclastic rocks. Kakajin Approximately 20% of our sites did not meet our criterion of The Kakajin locality consists of 11 sites, of which two (IR83 and k > 50, which is acceptable for sediments but not for single cooling IR84) are taken together, thus we calculate k values for 10 sites. units. After Eocene extrusive volcanism ended, a pulse of intrusive Some samples of sites IR83 and IR84 contain an unremoved com- activity started, which intruded into the Eocene volcanic succes- ponent, which is interpreted using great-circle analysis (Fig. 4G). sion. The intrusives were mainly emplaced from the Late Eocene To have enough set points for the great-circle analyses, these sites up to the Miocene. Intrusive bodies have formed a major role in were taken together. This locality has mostly reversed directions, hydrothermal metasomatism and resulting mineralization. Eocene A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 461 ) Stage Lutetian

al.,

continued on next page ( Reference Chiu 2013 HashtjinHashtjin Eocene Hashtjin Eocene Hashtjin Eocene Hashtjin Eocene Eocene Astara 45.3 Ma RaziRaziRazi Eocene Razi Eocene Hashtjin Eocene Eocene Hashtjin Eocene Hashtjin Eocene Eocene HashtjinHashtjin Eocene Eocene Hashtjin Oligocene Hashtjin Eocene HashtjinHashtjin Eocene Eocene Hashtjin Eocene 100k map Age Astara Paleocene Hashtjin Eocene

Unit (100k map) Kuv Pevt Epa2Epa3Epa3Ev RaziEv RaziEv RaziEv Eocene Et Eocene Eocene Et Et Et Et Olv2 E6an-baE6an-baE6an-ba TakestanE6an-ba Takestan Eocene TakestanE6an-ba Eocene Takestan Eocene E6an-ba Eocene TakestanE6an-baE6an-ba Eocene TakestanE6an-ba TakestanE6an-ba Eocene Takestan Eocene TakestanE6an-ba Eocene Takestan Eocene Eab Eocene Takestan Eocene Etl1 Ev2 Ev2 Ev2 Ev2 Ev2 Eab Eab Eab

red

basalt basalt basalt basalt basalt

basalt basalt

(ﬁeld) lava

grey andesitic lava lava lava

welded

grey grey andesitic large flow flow flow flow or grained flow flow breccia breccia breccia

and

Lithology Tuffbreccia Megaporphyritic Andesite-latite Lava Lava Lava Tuff Tuff Welded tuffbreccia Lava Lava tuff Redbeds Fine volcaniclastic sediments Andesite Red sediments Andesitic ﬂow Tuffbreccia Dark Dark Porphyritic andesite Porphyritic andesite Tuff Basaltic Basaltic Basaltic Reddish lava Grey lava Trachyandesite with phenocrysts Andesite Tuff Porphyritic Porphyritic Porphyritic Porphyritic Porphyritic Volcaniclastic sediment Megaporphyritic basalt dip 22

Bedding strike

36.129.7 220 13027.1 15 22018.7 10 22024.4 15 220 15 38.9 15 22049.3 15 220 15 25.7 220 15 38.1 220 15 − − − − − − − − − Inc (TC)

Dec (TC)

30.020.1 239.0 203.1 21.7 237.7 11.1 248.4 20.522.7 232.3 228.0 37.4 219.9 60.5 165.4 51.6 153.0 − − − − − − − − − (NOTC) Inc

Dec (NOTC) a95 Nk results.

and

lithology

location,

with

sites

sampled

IR059 Meshkin 37.01016 48.45117 8 23 11.9 40.3 32.7 53.2 45.2 85 20 IR004 Astara 38.44547 48.78607 5 167 5.9 341.4 55.9 26.0 10.3 330 70 IR100 Border 38.73457IR104 48.13535IR105 Border Border 6IR106 38.74585IR093 151 Border 38.74642 48.15819 Kajal 5.5 48.15885IR094 38.74778 5IR095 Kajal 3 48.15899 37.40682 63 Kajal 22.0 102 48.12985 9IR096 37.40659 9.7 12.3IR097 37.41470 14 39 Kajal 48.12921 32.1 Kajal 48.12993 144IR098 8 8.4 195.4 55.9 3.3 37.41495 18 Kajal 359.7 301IR031 37.41485 48.14776 69 48.0 3.4 3.2 167.5 Kakajin 48.14641 36.1 37.44623 27.9 10 4.2 160 7 36.42003 48.26146 89 195.0 53.4 63.0 19.1 49.89987 78 3 5.1 48.6 13.1 32.2 30 27.0 3 192.1 6.9 602 300 18.4 37.9 67.3 74 300 5.0 37.6 54.5 44.2 14.5 29.7 200 13.2 10 10 33.1 26.1 229 61.5 32.4 248.0 12 32.5 53.2 229 36.6 10 43.9 305 31.3 39.5 10 37.9 31.3 22 IR028 305 51.5 Meshkin 305 37.12424 22 67 48.35010 22 3 13 IR065 117 Meshkin 11.4IR066 37.00760 Meshkin 48.41446 37.00798 14.6 6 48.41171 294 5 27.6 3.9 522 23.9 3.4 30.5 20.3 358.4 0 51.8 43.6 45.3 359.5 62.1 57.6 85 85 14 14 IR101IR102 BorderIR103 Border Border 38.73457 38.73429 48.13535 38.74500 48.13530 6 48.15763 4 191 7 124 4.9 177 8.3 4.5 18.5 12.2 148.5 33.6 22.8 72.2 354.8IR083 356.6 47.6IR084 115.3 Kakajin 35.6IR085 Kakajin 74.4 160 36.39511 KakajinIR086 160 36.39483 49.89958 300 36.42505 Kakajin 49.89951 30 IR087 10 49.90437 30 IR088 36.42505 Kakajin 10 70IR089 6 Kakajin 49.90437IR090 36.43306 5.8 KakajinIR091 113 36.44063 5 Kakajin 49.90337 36.43935 6.3 Kakajin 49.89701 108IR092 together 36.44385 5 49.89172 204.4 36.40798 5 7.4 Kakajin with 49.88272 IR83 48IR026 5 49.90458 244.1 101 36.40798 5 Meshkin 11.2 75 5 7.6 49.90430 251.8 37.00705 156 8.9 74 48.40358 5 6.2 238.3 234.6 6 8.9 370 4.8 4.0 101 231.7 6.7 159.6 179.9 39.0 130 22.6 356.8 29.5 10 51.7 220 34.9 15 63.5 85 14 IR060IR061 MeshkinIR062 Meshkin 37.00926IR063 Meshkin 37.00909IR064 48.44878 Meshkin 37.00936 48.44653 Meshkin 37.00931 7 48.44628 37.00683 5 48.44594 66 5 48.41904 62 5 7.5 70 4 9.8 19 9.2 50 17.8 11.9 13.1 33.9 27.1 23.3 42.1 20.2 32.1 29.9 21.2 37.0 45.6 36.4 60.8 36.5 34.7 46.5 26.4 46.0 85 53.7 85 48.8 85 85 20 85 20 20 20 14 Name LocalityCH88 Latitude Astara Longitude 38.39232 48.65777 6 25 13.8 352.5 42.0 10.5 41.4 360 20 Table 1 List 462 A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 Stage Reference 100k map Age

Unit (100k map) Ea4 (250k map) Zanjan 250kEa4 (250k map) Eocene Ea4 (250k map) Zanjan 250k Zanjan 250k Eocene Ea4 (250k map) Eocene Zanjan 250kE6v Eocene E6v TakestanEv2Ev2 Eocene TakestanEs Eocene JirandehEblEbl JirandehEbl Eocene EblEbl Jirandeh Eocene Ebl LahrudEbl Lahrud Eocene Ebl LahrudEbl LahrudEbl Eocene LahrudEa2p Eocene LahrudEa2p Eocene LahrudEa2p Eocene LahrudEa2p Eocene LahrudEa2p Eocene LahrudEdl Eocene LahrudEdl Eocene LahrudEdl Eocene LahrudEdl Eocene Lahrud Eocene Edl Lahrud Eocene Edl Eocene LahrudEpa Eocene Lahrud Eocene LahrudEpa Lahrud Eocene LahrudEpa Eocene Lahrud Eocene LahrudEpa Eocene Eocene LahrudEpl Eocene Eocene Lahrud Eocene Lahrud Eocene Lahrud Eocene Eocene

basalt

(ﬁeld) grained grained grained grained grained

lava

welded welded welded welded welded

fine fine fine fine fine flow flow flow flow flow flow grained or or or or or flow flow flow flow

Lithology Very lava tuff Porphyritic Very lava tuff Very lava tuff Very lava tuff Very lava tuff Porphyritic andesite Porphyritic andesite Fine sediments Basalt Basalt Basalt Basalt Basalt Basalt Basalt Basalt Basalt Basalt Dacite Dacite Dacite Dacite Dacite Lava Lava Lava Lava Lava Lava Megaporphyritic lava Megaporphyritic lava Megaporphyritic lava Megaporphyritic lava Reddish dip

Bedding strike

15.6 128 20 21.5 6528.5 18 28.3 65 65 18 18 23.418.8 65 6551.921.4 65 18 65 18 18 18 22.532.7 12833.8 12828.4 128 20 12829.8 20 20 128 20 20 39.5 130 20 11.7 65 18 32.9 65 18 70.1 125 15 − − − − − − − − − − − − − − − − − Inc (TC)

Dec (TC)

16.2 231.1 21.818.5 227.2 215.6 3.6 197.7 9.3 199.6 5.818.411.1 227.5 232.1 222.3 42.120.1 220.8 244.3 13.814.2 196.6 205.5 10.6 200.0 19.6 224.2 20.9 207.3 55.2 206.9 − − − − − − − − − − − − − − − − Inc (NOTC)

Dec (NOTC) a95 Nk ) continued ( IR075IR076 Molla Ali Molla AliIR077 36.42239 36.42279 Molla Ali 49.49189 49.49198IR078 3 36.42300 3 Molla Ali 74 49.49209IR079 108 36.46414 3 Molla 14.4 Ali 11.9 49.51286 358.9IR080 872 353.0 36.47186 4 Molla Ali 45.4 4.2IR081 29.9 49.50750 150 Molla Ali 1.8IR082 357.5 36.50113 5 351.4 7.5 Molla 55.4 Ali 49.51282IR107 39.7 401 36.50766 41.9 6.7IR108 3 North 95 Talysh 49.51643 3.8IR109 95 36.58409 North TalyshIR110 38.69389 1.2 1095 5 North 69.2 Talysh 49.53320 322.1IR111 38.69369 47.71810 North 3.7 Talysh 10 IR112 38.69378 74 51.9 11 47.71802 North 10 Talysh 67.9IR113 38.69378 3 343.7 2.2 47.71679 North Talysh 275IR114 38.69359 3 95 47.71655 8.9 North 76.4 Talysh 15IR115 38.69326 3 297.2 47.71631 North 2.8 Talysh 70IR116 38.69311 3 23.6 4.5 47.71622 North 130 67.8 Talysh 37IR118 38.69302 3 33.0 21.2 47.71488 North 10 Talysh 14IR119 38.69280 6 14.8 47.71374 North 217.7 130 5.2 Talysh 115IR120 38.69251 3 31.6 20.7 10 47.71339 North 224.9 Talysh 51.2 34IR121 38.62611 3 33.8 47.71301 North 11.8 225.4 11.5 Talysh 210 32.0IR122 38.62625 3 47.77453 North 8.8 217.9 10 Talysh 65IR123 38.62625 3 225.2 11.6 3.7 47.77411 North 8.5 Talysh 168 215.5 60IR124 38.62590 4 47.77383 North 204.3 Talysh 39.6 122IR125 38.62593 4 9.5 3.2 47.77340 North 40.2 237.4 11.2 Talysh 351IR126 38.63072 3 47.77379 North 15.4 Talysh 60 56 200.3 IR127 38.63067 3 219.3 10 47.73427 North 225 7.2 Talysh 65 47IR128 38.63072 3 209.0 47.73487 North Talysh 44IR129 38.63050 3 7.1 47.73512 North 23.3 Talysh 69 38.63031 3 10 5.1 20 47.73515 North Talysh 1031 19.1IR130 38.63026 3 18 4.3 47.73544 87 47.4 50.8 38.63330 3 11.2 4.9 47.73568 North Talysh 33 12.7IR131 3 44.3 47.73049 13.7 550 38.63335 3 199.3 12.3 20.3 42.9 North Talysh 642IR132 3 18.1 43.8 47.72973 199.6 18.8 15.6 297 39.9 38.63292 57.2 North 207.3 15.0 Talysh 54.1 305IR133 3 201.6 47.72921 53.8 3.8 8.0 38.63280 205.7 125 9.8 North 52.4 13.3 Talysh 582 4 47.72864 202.2 125 52.9 38.55255 4.0 29.2 49.1 125 21.9 457 3 10 47.69409 125 16.1 7.8 10 125 5.3 121 205.2 8 10 39.9 17.0 4.9 77 10 27.9 10 223.5 4.7 41.9 6.4 27.4 210.2 57.4 130 5.0 130 59.5 20 130 20 20 Name LocalityIR074 Molla Ali Latitude Longitude 36.42217 49.49193 3 94 12.8 356.4 35.3 355.0 45.2 95 10 Table 1 A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 463 Stage Priabonian

al.,

Reference Chiu 2013 Takestan Eocene Tarom Eocene Takestan 35.8 Ma SoltaniyehSoltaniyeh Eocene Soltaniyeh Eocene SoltaniyehSoltaniyeh Eocene Soltaniyeh Eocene Soltaniyeh Eocene Soltaniyeh Eocene Soltaniyeh Eocene Tarom Eocene Eocene TaromTarom Eocene Tarom Eocene Tarom Eocene Tarom Eocene Tarom Eocene Tarom Eocene Tarom Eocene Eocene Tarom Eocene Tarom Eocene Eocene 100k map Age Takestan Eocene

(100k map) E6an E6an Ea6 (250k map) ZanjanEa6 250k (250k map) Eocene Zanjan 250kEtr-an Eocene Eka Eka Eka Eka Eka Eka Eka Eka Eka Eka8 Ekk1 Eka5 Eka5 Eka3 Ekk8 Ekk2 Ekk3 Eka5 E8a Eka1 Eka1 Unit

tra- tra-

grained grained (ﬁeld) and

andesite andesite

andesite

ﬁne ﬁne

andesite

chyandesite/latite chyandesite/latite Lithology Basaltic Basaltic Porphyritic Grey/purple porphyritic andesite Trachyandesite Trachybasalt Porphyritic Tuffbreccia Tuffbreccia Tuffbreccia Tuffbreccia Ignimbrite Ignimbrite Ignimbrite Porphyritic andesite Purple Andesite Tuffaceous sediments Andesite Dark volcaniclastics Andesite Dark volcaniclastics Andesite Andesite tuffbreccia Tuffaceous sediments Red dip

Bedding strike

62.570.0 123 12353.2 20 12357.6 20 123 20 20 67.6 5567.5 55 30 30 65.0 123 20 50.9 135 15 9.0 123 20 59.8 300 30 − − − − − − − − − − (TC) Inc

(TC) Dec

48.957.1 153.1 144.6 36.1 175.8 40.6 174.3 47.0 213.6 45.5 208.0 50.1 158.7 22.0 80.7 41.1 169.4 34.4 73.2 − − − − − − − − − − (NOTC) Inc

Dec (NOTC) a95 Nk ) continued ( IR016 Takestan 36.06562 49.63717 6 136 5.8 174.1 IR023 Takestan 36.22788 49.32134 4IR022IR050 Valayesh 46 Valayesh 36.48612IR051 13.8 36.47618IR052 48.98974 Valayesh 39.2IR053 48.99030 Valayesh 5 36.47314IR054 Valayesh 4 36.47210IR055 50.4 48.99009 Valayesh 13 36.47289IR056 48.98996 Valayesh 7 7 36.46910IR057 48.99002 22.2 Valayesh 44.8 6 36.46166IR020 48.98752 Valayesh 74 181.0 4 38.5 36.46099 48.96946 70.1 Zaaker 129 6 36.46075IR021 84.9 48.96982 7.1 156 39.0 5 5.9 48.97038 123 Zaaker 29 36.67273 4 7.4IR068 2.8 82 175.5 3 48.72948 186.7 12.7 Zaaker 44 36.73357 177.1 IR069 20 14.1 21.4 6 97 14.8 48.79146 61.1IR070 8.5 Zaaker 36.68824 186.4 45 12.6 123 Zaaker 8 48.73705 49.6 180.6 324.0 36.69500 186.8 10.1 63 8 36.70414 74.9 48.73847 20 0.5 16.2 48.75034 7.0 28 3 123IR017 5 67.8 41.6 21.6 10.6 77 ZanjanIR018 104 59.1 20 123 14.2 19.5 41.9 Zanjan 36.71437 7.6IR019 94.7 41.3 48.50094 12.2 Zanjan 22.6 36.78695 20 19.7 12 50.5 48.50551 300 70.5 56.8 36.78844 46.8 70 8 48.51714 50.1 113.1 117 5.2 30 347.7 42 7 50.8 103 5.2 69.7 8.6 89 15 105 139 20.6 14 6.4 25.7 15 10.1 41.1 30 8.7 24.9 16.0 33.7 50.1 26.4 60 37.9 135 10 44 10 29 IR024 Takestan 36.10048IR030 49.47698 Takestan 3 36.08253 49.54280 82 3 13.7 365 303.0 4.8 50.3 352.1 283.2 57.1 42.7 305.9 135 70.4 20 120 25 Name LocalityIR015 Latitude Takestan Longitude 36.06749 49.63571 6 139 5.7 176.3 IR067 Zaaker 36.68324 48.73213IR071 2IR072 Zaaker 26 ZaakerIR073 36.72064 50.6 Zaaker 36.70624 48.77127 63.7 48.75715 5 36.66836 12 49.6 48.72574 41 65 5 12.1 57.8 5.4 501 181.4 20.6 18.4 3.4 315 54.7 41.4 30 9.9 54.3 135 15 Table 1 464 A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 tuffites and volcanic rocks are affected by extensive metasomatism from the South Armenian block, as this block is located south of a and scattered vein mineralization (Ghorbani, 2013). Hydrothermal Cretaceous–Eocene suture. The SAB is the indentor with respect to alteration might be a possible explanation for the low k values the orocline, and may have undergone local or regional rotations that we find in some volcanic rocks, as they could result in (par- due to collision. tial) overprints. Nonetheless, if we include also sites with k < 50, For the Pontides domain, only two Eocene localities were ob- the result is identical within errors (Dx, Ix). Applying the tilt tained from limestones and volcanic rocks. For the Eastern Pon- ◦ corrections increases the inclination significantly by some 10 , but tides domain, three localities consisting of volcanic and volcani- does not significantly change the declination and thus the rotation clastic deposits were used. Considering the relatively small amount (Table 2). Inclinations are generally too shallow, even after tilt cor- of Eocene paleomagnetic directions in the Eastern Pontides of rection. This is a much reported problem for Eocene rocks (e.g. Si Turkey, future studies are expected to improve the estimates pro- and Van der Voo, 2001), for which yet no plausible explanation is vided in this study. The Lesser Caucasus has many more sites, found. atotal of 26 accepted localities, with mostly volcanic and volcaniclastic deposits and some turbiditic sedimentary rocks (Meijers et 5.2. North Takestan lineament al., 2015). We performed an orocline test averages for the Pontides, East- The Talysh mountains show an abrupt shift near Takestan: the ern Pontides, Lesser Caucasus and Talysh blocks (Eastern Alborz southern edge of the Alborz jumps approximately 40 km north- of Cifelli et al., 2015 is within error the same), which results in ward, over a roughly north–south trending line. Although there is a slope of 0.655, with a Pearson’s ρ of 0.997. This indicates that no major fault drawn on any map, this lineament is sometimes about 65% of the rotations can be explained by post-Eocene cur- mentioned as the North Takestan fault, or Takestan–Rasht fault vature. This slightly more than the 50% post-Eocene curvature of (e.g. Azizi and Moinevaziri, 2009). The Molla Ali locality is rela- the study of Meijers et al. (2015), which is probably caused by not tively close to this inferred fault, at roughly 5km distance, and taking into account the data of the SAB in our reconstruction. thus could be affected by movement along the fault. Hence, we de- cided to use only the 6 northern localities as representative for the 5.4. Quantifying Arabia–Eurasia convergence Talysh mountains, north of Valayesh since the southern 4 localities may have been affected by regional tectonics. Nonetheless, our We estimate the amount of convergence accommodated in the strict criteria do not make a significant difference for the amount Greater Caucasus fold-thrust belt from a first-order map view of rotation, as mean declinations are similar for 10 localities and 6 restoration back to 35 Ma. Paleomagnetically coherent blocks as localities (Fig. 5). Averaging all site means of the 6 northern locali- determined above were drawn based on the position of paleomag- ◦ ties gives a mean declination D ± Dx = 25.9 ± 6.1 for the Talysh netic sites and tectonic boundaries. Our reconstruction assumes Mountains of NW Iran. that the eastern Alborz and the Pontides were not moving relative to Eurasia since the late Eocene. There is evidence for thrusting 5.3. Literature data to the north of these domains, e.g. in the South Caspian Basin (Hollingsworth et al., 2008), and our convergence estimates are We complement our new data set with previous paleomag- therefore minimum values required to explain the paleomagnetic netic work from the Eastern Pontides to the Lesser Caucasus region constraints. Furthermore, purely northward motions not resulting (see the compiled data and corresponding references in Table A1). in rotations cannot be accounted for in this approach. The Arabia– Paleomagnetic data in the Eastern Pontides – Lesser Caucasus – Eurasia collision has caused deformation of tectonic blocks, which Talysh – Alborz region was grouped based on the geology and the GPlates reconstruction does not account for. However, it is geometry (like strike trend) into coherent domains. Based on co- known that Iran has shortened due to the Arabia–Eurasia colli- herent paleomagnetic results and geometry, we define coherently sion (e.g. Mouthereau et al., 2012 and references therein). In our rotating domains based on our paleomagnetic data (and thus are reconstruction at 35 Ma, Central Iran is thus drawn in up to the a simplification of the true deformation history). Two of our do- Neotethys suture zone as defined in GPlates. However, as it is mains are within the Eastern Pontides region of Turkey, but for the a relatively unexplored region, not all deformation of blocks is sake of clarity we call the most eastern one the Eastern Pontides well constrained. Thus, reconstructing the rotation of newly de- domain, and the other the Pontides domain. We then distinguish fined rigid blocks relative to each other often results in overlap of five domains: the Pontides, the Eastern Pontides, the Lesser Cau- blocks or gaps between blocks. Our reconstruction is subsequently casus, the Talysh and the Alborz (Fig. 6). The new data from our tested using the paleomagnetic constraints. For this, we use an it- study are taken as representative for the Talysh domain. These data erative approach, in which we determine total Euler reconstruction are consistent with the results of Cifelli et al. (2015), who report poles from 0–35 Ma of each block relative to Eurasia (Table A3). ◦ a mean declination of 23.4 for the post-Eocene of the western We then use these Euler rotations to predict the Global Apparent limb of the Alborz Mountains. The expected declination from the Polar Wander Path (GAPWaP) of Torsvik et al. (2012) in the coor- Eurasia apparent polar wander path for Eocene rocks is around 10 dinates of each domain, (Table A2) using a thereto designed tool degrees, for the whole region from the Pontides to the Central Al- on Paleomagnetism.org (Li et al., 2017). We then iteratively update borz (Torsvik et al., 2012). Thus, rotations were calculated with our reconstruction until the paleomagnetic data overlap with the respect to this expected declination. In addition, we recalculated polar wander paths as predicted by the reconstruction, and a geo- ◦ ◦ all mean directions to the average location 41 N, 45 E, which we metrically and kinematically coherent result (at 35 Ma) is obtained use as a reference point. For the Pontides, Eastern Pontides and (Fig. 7). Lesser Caucasus domains, we parametrically resampled published Our reconstruction shows that, to fulfil the paleomagnetic con- data in Paleomagnetism.org (see Table A1). We only took data of straints on regional vertical axis rotations, a minimum of ∼120 km Eocene age, from localities that were accepted in the review of of convergence must have been accommodated north of the Talysh Meijers et al. (2015; and references therein), and subsequently cal- (Fig. 6). North of the Eastern Pontides and the Lesser Cauca- culated the means of all resampled data per domain (Table 2). The sus, a minimum of 200–280 km convergence must be accommo- file Eocene_directions_literature.pmag contains paleomagnetic data dated, which constrains the amount of convergence accommodated from the Pontides, Eastern Pontides and Lesser Caucasus that were within the Caucasus orogeny. This sharp difference in Caucasus previously published (see Table A1 for details). We do not use data convergence between the Lesser Caucasus and Talysh (Fig. 6) re- A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 465

λ details

(for

x I studies

6.4 20.3 6.0 20.2 6.3 17.4 6.6 25.9 7.36.7 23.7 17.3 6.9 23.1 6.2 25.6 multiple

x D from 4.6 4.3 4.2 5.8 6.0 4.4 5.5 5.4

data

max consist

5.8 5.0 6.4 5.9 7.6 7.6 6.4 A95 5.1 domains

min other

the

while

minPalat maxPalat latitude longitude age min age max age minPalat maxPalat latitude longitude age min age max age x x A95 A95 I I 2015 ),

al.,

x x et D D

K Cifelli (

S S study

cut cut 95 one

α from max max

A95 A95 domain min min

Alborz

A95 A95 A95 A95 the

Rk from

VGP VGP R R Data

domain.

per

22.2 44.2 60.1 13.2 5.0 12.5 5.2 2.3 Dec Inc 20.3 36.4 62.4 14.3 4.7 16.9 4.3 2.2 24.9 31.9 41.5 17.4 5.3 26.8 4.2 2.6 23.5 36.4 78.7 13.3 4.4 15.2 4.1 2.0 25.9 41.3 41.1 14.9 5.8 16.6 5.4 2.6 28.326.8 40.5 32.1 52.8 53.5 13.4 16.0 5.3 4.9 14.8 22.9 5.1 4.0 2.4 2.4 26.2 43.8 75.2 11.8 4.7 11.4 4.8 2.1 results

lR K lR K 95 95 average

45 α α and

k k Talysh

NN 74 65 47 44 94 82 61 57 the

Dec Inc Dec Inc localities notc 74 67 notc 47 44 notc 61 57 notc 94 85 tc tc

45 45 and

of 50 tc 50 tc NN NN 63 6321693 213 330.81213 93 38.4 23.4 117747 29.1 355.2 35.5 344.3 3.4 51.3 9.4 44 35.8 22.8 21.7 45.0 3.3 0.9 60.9 24.9 2.2 19.663 32.0 31.9 19.8 32.0 190.4 1125.4 63 17.4216 91.0 61.1 20.3 13.693 5.3 213 1119.1 197.4 330.81213 61.4 3.2 17.3 0.9 93 38.4 23.4 1177 91.5 2.7 41.5 2.347 0.7 29.1 355.2 35.5 1.4 344.3 1.9 3.4 51.3 26.8 9.4 44 6.0 35.8 22.8 2.0 21.7 42.4 1.0 45.0 2.8 3.3 0.9 60.9 25.9 2.2 4.2 19.6 45.0 32.0 4.7 45.0 41.3 19.8 32.0 190.4 14.4 45.0 2.6 1125.4 18.1 14.9 91.0 61.1 3.5 22.3 20.3 13.6 1.1 45.0 5.8 2.9 1119.1 197.4 7.6 4.6 61.4 3.2 10.4 23.7 1.0 0.9 4.1 91.5 2.7 2.0 18.6 2.3 41.1 31.0 0.7 45.0 17.0 1.4 2.8 1.9 16.6 15.8 6.0 25.0 18.0 2.0 41.4 1.0 32.9 4.4 2.8 22.4 6.7 5.4 45.0 41.60 4.7 21.7 45.0 41.00 14.4 45.0 13.3 2.6 35.50 18.1 41.80 3.5 22.3 45.00 1.1 45.0 40.40 52.00 2.9 7.6 21.8 4.6 10.4 1.0 35 4.1 39.90 35 2.0 18.6 35 31.0 33.9 45.0 17.0 33.9 37.50 2.8 20.1 35 25.0 18.0 56 48.50 32.9 6.0 33.9 56 22.4 7.3 41.6 21.7 35 41 56 18.6 35.5 33.9 41.8 40.4 52 45 29.6 56 35 39.9 37.5 33.9 35 35 35 33.9 48.5 56 33.9 56 35 56 33.9 56

> > all k k results

Name Name

Pontides Caucasus Pontides Caucasus Table A1).

Tectonic Coordinates # Localities 10 Site Eastern Alborz Pontides Lesser Talysh Site Eastern Alborz Pontides Lesser Talysh 6 Geographic Coordinates 10 all 6 Table 2 Combined see 466 A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469

Fig. 5. Averages of all sites for 6 and 10 localities. quires that a large dextral transform fault existed between the Pontides and the Lesser Caucasus (Fig. 6), then the rest of the Anatolian and Iranian domains after the late Eocene. Barrier et al. 800–900 km of Arabia–Eurasia convergence (McQuarrie and van (2008) already suggested the existence of such a fault since the Hinsbergen, 2013)must have been accommodated to the south of early Eocene, which may coincide with the ancient plate bound- the Lesser Caucasus in the East Anatolian plateau. South of the ary bounding the Iranian Cimmerides in the west. The difference Talysh, a maximum of 780 km must have been partitioned over in convergence would likely result in differences of accommo- Iranian plateau shortening and subduction in the Zagros. Our esti- dation in the Greater Caucasus. Indeed, there appear to be real mate of convergence accommodated north of the Talysh may add and signiﬁcant differences between various aspects of western an additional 120 km of overriding plate convergence to the esti- and eastern Greater Caucasus including crustal structure, poten- mate of McQuarrie and van Hinsbergen (2013), which may push tial timing of exhumation and possible amounts of shortening. the age of Arabia collision in northwest Iran a few million years (e.g. Cowgill et al., 2016; Ershov et al., 2003; Forte et al., 2014; back. Mumladze et al., 2015). Our reconstruction provides the ﬁrst quan- There is widespread debate on the timing of collision of Ara- titative estimate that this fault zone may have accommodated as bia with the Taurides, or the East Anatolian accretionary prism, much as 160 km of right-lateral, post-late Eocene slip. We hypoth- with estimates ranging from as old as ∼50 Ma to as young as esize that the Arax fault is a present-day remnant of this transform ∼5Ma, and on how, when and where post-collisional conver- fault, although this fault is believed to be left-lateral (see Fig. 1). gence was accommodated (Cowgill et al., 2016; Hüsing et al., 2009; Our estimate is based on paleomagnetic data, and the 120– Okay et al., 2010; Rolland et al., 2012; Vincent et al., 2016). Our 280 km post-Eocene convergence in the Caucasus is an indepen- new constraint on the partitioning of convergence into the Cau- dent corroboration of previous estimates based on seismological casus realm now places quantitative constraints on the area that observations (Mumladze et al., 2015), who interpreted a slab-like must have been consumed after 35 Ma to the south of the Lesser body below the Greater Caucasus of up to 280 km down-dip Caucasus and aids future studies that aim to determine how the length. Furthermore, our reconstruction is reasonably consistent remaining convergence was partitioned over subduction, plateau with the estimate of Cowgill et al. (2016), who suggested, based shortening, and extrusion. Obtaining further constraints on how on sediment provenance data, that an ocean basin south of the much, when and where this convergence was accommodated using western Greater Caucasus of as much as 350–400 km wide has our paleomagnetic method combined with GPlates for quantitative closed. reconstruction is very promising. Clearly, it is a very useful tool If a minimum of 200–280 km of convergence was accom- for the analysis of the effects of continent–continent collision on modated in the Caucasus subduction zone, north of the Eastern orogenesis, plateau rise, and extrusion. A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 467

Fig. 6. Reconstruction of the Caucasus orocline and quantiﬁcation of the partitioning of Arabia–Europe convergence between 35 Ma and 0Ma. Modiﬁed GPlates reconstruction software output for our reconstruction at 0Ma and 35 Ma, and averages for parametrically sampled paleomagnetic data for Pontides, Eastern Pontides, Lesser Caucasus and Talysh blocks. Data in dark grey fall outside of the cut-off and are rejected for calculation of the average. Open circles represent negative inclinations. Estimated total reconstruction poles at 35 Ma relative to Eurasia for the segments or the orocline are given in Appendix A3.

Fig. 7. Apparent polar wander path of Eurasia (Torsvik et al., 2012)compared to the apparent polar wander paths that we calculated for each block (Li et al., 2017)on the ◦ ◦ basis of the rotation poles of our best ﬁt Gplates reconstruction for a reference location at 41 N, 45 E. The average declination (D; with error Dx) per block is given at 35 Ma; the age error bar spans the entire Eocene. 468 A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469

6. Conclusions Bazhenov, M.L., Burtman, V.S., 2002. Eocene paleomagnetism of the Caucasus (southwest Georgia): oroclinal bending in the Arabian syntaxis. Tectono- physics 344, 247–259. We provide new paleomagnetic data from the Talysh of NW Berberian, M., King, G.C.P., 1981. Towards a paleogeography and tectonic evolution Iran from which we derive a consistent clockwise rotation with of Iran. Can. J. Earth Sci. 18, 210–265. ◦ a mean declination D ± Dx = 25.9 ± 6.1 . We then calculate Biggin, A.J., Van Hinsbergen, D.J.J., Langereis, C.G., Straathof, G.B., Deenen, M.H.L., first order approximations of convergence in the Greater Caucasus 2008. Geomagnetic secular variation in the Cretaceous Normal Superchron and region, using kinematic restorations of vertical axis rotations inter- in the Jurassic. Phys. Earth Planet. Inter. 169, 3–19. Chiu, H.-Y., Chung, S.-L., Zarrinkoub, M.H., Mohammadi, S.S., Khatib, M.M., Iizuka, Y., preted from paleomagnetic declinations of tectonic blocks in the 2013. Zircon U–Pb age constraints from Iran on the magmatic evolution related Eastern Pontides – Lesser Caucasus – Talysh orocline. We estimate to Neotethyan subduction and Zagros orogeny. Lithos 162–163, 70–87. convergence taken up in the Greater Caucasus to be a minimum Cifelli, F., Ballato, P., Alimohammadian, H., Sabouri, J., Mattei, M., 2015. Tectonic of 120 km in the east, and 200–280 km in the west. Our recon- magnetic lineation and oroclinal bending of the Alborz range: implications on the Iran–Southern Caspian geodynamics. Tectonics 34, 116–132. struction estimates that these domains are separated by a large Cowgill, E., Forte, A.M., Niemi, N., Avdeev, B., Tye, A., Trexler, C., Javakhishvili, dextral transform fault zone that accommodated ∼160 km of slip Z., Elashvili, M., Godoladze, T., 2016. Relict basin closure and crustal shorten- since the late Eocene, of which the presently observed Arax fault ing budgets during continental collision: an example from Caucasus sediment might have been part. Our results provide independent corrobora- provenance. Tectonics, 2918–2947. Deenen, M.H.L., Langereis, C.G., van Hinsbergen, D.J.J., Biggin, A.J., 2011. Geomag- tion of recent estimates of a subducted slab with a length of up to netic secular variation and the statistics of palaeomagnetic directions. Geophys. 280 km underneath the Greater Caucasus (Mumladze et al., 2015). J. Int. 186, 509–520. Our analysis suggests that ∼600 km of post-Eocene Arabia–Europe Dilek, Y., Altunkaynak, S.,¸ 2010. Geochemistry of Neogene–Quaternary alkaline vol- convergence must have been accommodated in and south of the canism in western Anatolia, Turkey, and implications for the Aegean mantle. Int. Geol. Rev. 52, 631–655. east Anatolian plateau, and ∼780 km within and south of the Ira- Doroozi, R., Vaccaro, C., Masoudi, F., Petrini, R., 2016. Cretaceous alkaline volcanism nian plateau. These constraints serve as a boundary condition on in south Marzanabad, northern central Alborz, Iran: geochemistry and petroge- future studies that constrain how convergence is partitioned over nesis. Geosci. Front. 7, 1–15. plateau growth and Neotethyan subduction, and the role of conti- Ershov, A.V., Brunet, M.F., Nikishin, A.M., Bolotov, S.N., Nazarevich, B.P., Korotaev, nental collision therein. M.V., 2003. Northern Caucasus basin: thermal history and synthesis of subsi- dence models. Sediment. Geol. 156, 95–118. Forte, A.M., Cowgill, E., Whipple, K.X., 2014. Transition from a singly vergent to Acknowledgements doubly vergent wedge in a young orogen: the Greater Caucasus. Tectonics 33, 2077–2101. Ghorbani, M., 2013. The Economic Geology of Iran. Springer. This work was financially supported by the Netherlands Or- Gravand, R., Golgir, Z., 2014. Biostratigraphy of the Eocene sediments in Alborz ganization for Scientific Research (NWO) through the VICI grant Province, Iran. Adv. Environ. Biol. 8, 1285–1292. 865.10.011 of WK and the VIDI grant 864.11.004 of DJJvH, while Hisarlı, Z.M., 2011. New paleomagnetic constraints on the late Cretaceous and early DJJvH and DG acknowledge ERC Starting Grant number 306810 Cenozoic tectonic history of the Eastern Pontides. J. Geodyn. (SINK). We thank Eric Cowgill, Adam Forte and anonymous review- Hollingsworth, J., Jackson, J., Walker, R., Nazari, H., 2008. Extrusion tectonics and subduction in the eastern South Caspian region since 10 Ma. Geology 36, ers for their comments which improved the manuscript. 763–766. Hüsing, S., Zachariasse, W.-J., van Hinsbergen, D.J.J., Krijgsman, W., Inceöz, M., Appendix A. Supplementary material Harzhauser, M., Mandic, O., Kroh, A., 2009. Oligocene–Miocene basin evolution in SE Anatolia, Turkey: constraints on the closure of the eastern Tethys gate- way. In: Collis. Collapse Africa-Arabia–Eurasia Subduction Zo., Geol. Soc. London, We provide online supplementary information in the form of an Spec. Publ. 311, 107–132. appendix. It can be found online at https://doi.org/10.1016/j.epsl. Jackson, J., Mckenzie, D., 1983. Active tectonics of the Alpine–Himalayan Belt be- 2017.11.025. It contains all GPS data of sites (in decimal degrees, tween western Turkey and Pakistan. Geophys. J. R. Astron. Soc. 77, 185–264. geodetic datum WGS84) as a.kml file, the paleomagnetic data Jackson, J., Priestley, K., Allen, M., Berberian, M., 2002. Active tectonics of the South Caspian Basin. Geophys. J. Int. 148, 214–245. including the site.dir and locality.pmag files for the web portal Koymans, M.R., Langereis, C.G., Pastor-Galán, D., van Hinsbergen, D.J.J., 2016. Pale- Paleomagnetism.org. Our GPlates reconstruction files are supplied omagnetism.org: an online multi-platform open source environment for paleo- as GPlates_Caucasus.gpml and GPlates_rotation.rot. Literature data magnetic data analysis. Comput. Geosci. 93, 127–137. that went into the reconstruction is supplied in Table A1. Rotation Li, S., Advokaat, E.L., van Hinsbergen, D.J.J., Deng, C., Zhu, R., 2017. Paleomagnetic constraints on the Mesozoic–Cenozoic paleolatitudinal and rotational history poles that are used for calculating the apparent polar wander paths of Indochina and South China: review and updated kinematic reconstruction. are supplied in Table A2. Table A3 contains estimated total recon- Earth-Sci. Rev. 171, 58–77. struction poles at 35 Ma of the four blocks of the Pontides–Lesser McFadden, P.L., McElhinny, M.W., 1988. The combined analysis of remagnetization Caucasus–Talysh orocline. Rotating the four blocks of the orocline circles and direct observations in palaeomagnetism. Earth Planet. Sci. Lett. 87, 161–172. shown in Fig. 6 over these poles obeys the paleomagnetic data of McQuarrie, N., van Hinsbergen, D.J.J., 2013. Retrodeforming the Arabia–Eurasia col- each block (Fig. 7) and were used to estimate total post-35 Ma lision zone: age of collision versus magnitude of continental subduction. Geol- convergence accommodated within the Caucasus orogen. ogy 41, 315–318. Meijers, M.J.M., Smith, B., Pastor-Galán, D., Degenaar, R., Sadradze, N., Adamia, S., Sa- hakyan, L., Avagyan, A., Sosson, M., Rolland, Y., Langereis, C.G., Müller, C., 2015. References Progressive orocline formation in the Eastern Pontides – Lesser Caucasus. In: Tectonic Evolution of the Eastern Black Sea and Caucasus, Geol. Soc. (Lond.) Adamia, S., Alania, V., Chabukiani, A., Kutelia, Z., Sadradze, N., 2011a. Great Caucasus Spec. Publ. 428. (Cavcasioni): a long-lived North-Tethyan Back-Arc Basin. Turk. J. Earth Sci. 20, Morley, C.K., Kongwung, B., Julapour, A.A.A., Abdolghafourian, M., Hajian, M., Waples, 611–628. D., Warren, J., Otterdoom, H., Srisuriyon, K., Kazemi, H., 2009. Structural devel- Adamia, S., Zakariadze, G., Chkhotua, T., Sadradze, N., Tsereteli, N., Chabukiani, A., opment of a major late Cenozoic basin and transpressional belt in central Iran: Gventsadze, A., 2011b. Geology of the Caucasus: areview. Turk. J. Earth Sci. 20, the Central Basin in the Qom-Saveh area. Geosphere 5, 325–362. 489–544. Mouthereau, F., Lacombe, O., Vergés, J., 2012. Building the Zagros collisional orogen: Agard, P., Omrani, J., Jolivet, L., Whitechurch, H., Vrielynck, B., Spakman, W., Monié, Timing, strain distribution and the dynamics of Arabia/Eurasia plate conver- P., Meyer, B., Wortel, R., 2011. Zagros orogeny: a subduction-dominated process. gence. Tectonophysics 532–535, 27–60. Geol. Mag. 148, 692–725. Mumladze, T., Forte, A.M., Cowgill, E.S., Trexler, C.C., Niemi, N.A., Burak Yikilmaz, Azizi, H., Moinevaziri, H., 2009. Review of the tectonic setting of Cretaceous to Qua- M., Kellogg, L.H., 2015. Subducted, detached, and torn slabs beneath the Greater ternary volcanism in northwestern Iran. J. Geodyn. 47, 167–179. Caucasus. GeoResJ 5, 36–46. Barrier, E., Vriekynck, B., Bergerat, F., Brunet, M.F., Mosar, J., Poisson, A., Sosson, M., Okay, A.I., Özcan, E., Cavazza, W., Okay, Ni., Less, G., 2010. Basement types, Lower 2008. Palaeotectonic maps of the Middle East: tectono-sedimentary-palinspastic Eocene series, Upper Eocene olistostromes and the initiation of the Southern maps from Late Norian to Pliocene. Thrace Basin, NW Turkey. Turk. J. Earth Sci. 19, 1–25. A. van der Boon et al. / Earth and Planetary Science Letters 482 (2018) 454–469 469

Rezaeian, M., Carter, A., Hovius, N., Allen, M.B., 2012. Cenozoic exhumation history van der Boon, A., Kuiper, K.F., Villa, G., Renema, W., Meijers, M.J.M., Langereis, C.G., of the Alborz Mountains, Iran: new constraints from low-temperature chronom- Aliyeva, E., Krijgsman, W., 2015. Onset of Maikop sedimentation and cessation etry. Tectonics 31. of Eocene arc volcanism in the Talysh Mountains, Azerbaijan. Geol. Soc. (Lond.) Rolland, Y., Perincek, D., Kaymakci, N., Sosson, M., Barrier, E., Avagyan, A., 2012. Ev- Spec. Publ. 428. idence for ∼80–75 Ma subduction jump during Anatolide–Tauride–Armenian Van Hinsbergen, D.J.J., Lippert, P.C., Dupont-Nivet, G., McQuarrie, N., Doubrovine, block accretion and ∼48 Ma Arabia–Eurasia collision in Lesser Caucasus–East P.V., Spakman, W., Torsvik, T.H., 2012. Greater India Basin hypothesis and a two- Anatolia. J. Geodyn. 56–57, 76–85. stage Cenozoic collision between, India and Asia. Proc. Natl. Acad. Sci. USA 109, ,¸Sengör A.M.C., Özeren, S., Genç, T., Zor, E., ¸Sengör, A.M.C., Özeren, S., Genç, T., Zor, 7659–7664. E., 2003. East Anatolian high plateau as a mantle-supported, north–south short- Verdel, C., Wernicke, B.P., Hassanzadeh, J., Guest, B., 2011. A Paleogene extensional ened domal structure. Geophys. Res. Lett. 30, 8045. arc flare-up in Iran. Tectonics 30. Si, J., Van der Voo, R., 2001. Too-low magnetic inclinations in Central Asia: an indi- Vincent, S.J., Allen, M.B., Ismail-Zadeh, A.D., Flecker, R., Foland, K.A., Simmons, M.D., cation of a long-term Tertiary non-dipole field? Terra Nova 13, 471–478. 2005. Insights from the Talysh of Azerbaijan into the Paleogene evolution of the Solaymani Azad, S., Dominguez, S., Philip, H., Hessami, K., Forutan, M.R., Shahpasan South Caspian region. Geol. Soc. Am. Bull. 117, 1513–1533. Zadeh, M., Ritz, J.F., 2011. The Zandjan fault system: morphological and tectonic Vincent, S.J., Braham, W., Lavrishchev, V.A., Maynard, J.R., Harland, M., 2016. The evidences of a new active fault network in the NW of Iran. Tectonophysics 506, formation and inversion of the western Greater Caucasus Basin and the uplift 73–85. of the western Greater Caucasus: implications for the wider Black Sea region. Sosson, M., Rolland, Y., Muller, C., Danelian, T., Melkonyan, R., Kekelia, S., Adamia, S., Tectonics 35, 1–15. Babazadeh, V., Kangarli, T., Avagyan, a., Galoyan, G., Mosar, J., 2010. Subductions, Vissers, R.L.M., Van Hinsbergen, D.J.J., Van Der Meer, D.G., Spakman, W., 2016. Creta- obduction and collision in the Lesser Caucasus (Armenia, Azerbaijan, Georgia), ceous slab break-off in the Pyrenees: Iberian plate-kinematics in paleomagnetic new insights. Geol. Soc. (Lond.) Spec. Publ. 340, 329–352. and mantle reference frames. Gondwana Res. 34, 49–59. Stampfli, G.M., Borel, G.D., 2002. A plate tectonic model for the Paleozoic and Meso- Zanchetta, S., Zanchi, a., Villa, I., Poli, S., Muttoni, G., 2009. The Shanderman eclog- zoic constrained by dynamic plate boundaries and restored synthetic oceanic ites: aLate Carboniferous high-pressure event in the NW Talesh Mountains (NW isochrons. Earth Planet. Sci. Lett. 196, 17–33. Iran). Geol. Soc. (Lond.) Spec. Publ. 312, 57–78. Torsvik, T.H., Van der Voo, R., Preeden, U., Mac Niocaill, C., Steinberger, B., Zanchi, A., Berra, F., Mattei, M., Ghassemi, M.R., Sabouri, J., 2006. Inversion tectonics Doubrovine, P.V., van Hinsbergen, D.J.J., Domeier, M., Gaina, C., Tohver, E., Meert, in central Alborz, Iran. J. Struct. Geol. 28, 2023–2037. J.G., McCausland, P.J.A., Cocks, L.R.M., 2012. Phanerozoic polar wander, palaeo- geography and dynamics. Earth-Sci. Rev. 114, 325–368.