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Simplified geological map of the west-central Balkan Peninsula, showing major tectonic zones and ophiolite occurrences. Key to lettering for different Jurassic ophiolites in the region (from north to south): Trp — Tropoja, Krb — Krrabi, Kuk — Kukesi, Puk — Puke, Skd — Skenderbeu, Blq — Bulqize, Shp — Shpati, She — Shebenik, Vo — Voskopoja, Pin — Pindos, Vou — Vourinos, Koz — Koziakas, Oth — Othris.
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Neotethyan suprasubduction zone ophiolites represent anomalous oceanic crust developed in older host basins during trench rollback cycles and later entrapped in orogenic belts as a result first of trench-passive margin and then continent–continent collisions. The Middle Jurassic Mirdita zone ophiolites in northern Albania constitute a critical tran...
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... NNW-trending Neotethyan ophiolites in the Balkan Peninsula occur in two distinct zones bounding the Pelagonian ribbon continent (Fig. 2). The Vardar Zone ophiolites, also known as the "Innermost Hellenic ophiolites" (Smith, 1993) or the "Eastern Hellenic ophiolites", are located east of Pelagonia and are Jurassic-Early Cretaceous in age ( Bébien et al., 1986;Mussallam and Jung, 1986;Robertson, 2002). Although most of the Vardar Zone ophiolites are highly disrupted and ...
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... Vardar Zone ophiolites separate the Pelagonian micro- continent from the Serbo-Macedonian Zone to the east, which represents the Jurassic-Early Cretaceous active margin of Eurasia (Fig. 2). Middle Jurassic calc-alkaline plutons and extrusive rocks (Chortiatis unit) in the western edge of the Serbo-Macedonian Zone constitute a magmatic arc developed along the southern margin of Eurasia ( Schunemann, 1985;Mussallam and Jung, 1986). The Paikon volcanic complex west of both the Chortiatis unit and the Guevgueli ophiolite is ...
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... ophiolites in Greece and Albania, the Mirdita ophiolites in northern Albania and their northward continuation into Kosovo and Serbia, and the Dinaric ophiolites in Bosnia and Croatia collectively form the Pindos Zone ophiolites in the Balkan Peninsula. These ophiolites show bidivergent emplacement onto Pelagonia in the east and Apulia in the west (Fig. 2). Similar to their counterparts in the Vardar Zone, they also display geochemical affinities ranging from MORB, IAT, to boninitic compositions ( Beccaluva et al., 1984;Shallo et al., 1990;Bébien et al., 1998;Clift and Dixon, 1998;Pe-Piper and Piper, 2002;Dilek and Flower, 2003), indicating subduction zone involve- ment in their ...
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... Pindos Zone ophiolites in southern Albania occur in a NW-trending belt, which makes a sharp 90° turn into a short NE-trending segment in northern Albania before it joins the NW-oriented Dinaric ophiolite belt (Fig. 2). This NE-trending short segment is known as the Mirdita zone in the literature and also corresponds to the Shkoder-Peç lineament on the tectonic map of Albania (Robertson and Shallo, 2000;). This lineament and the Mirdita zone ophiolites sharply truncate the pre-Apulian carbonate platform and flysch deposits in the Dinarides (Malesia e ...
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... lineament on the tectonic map of Albania (Robertson and Shallo, 2000;). This lineament and the Mirdita zone ophiolites sharply truncate the pre-Apulian carbonate platform and flysch deposits in the Dinarides (Malesia e Madhe and Valbona) on the west and the northeasterly turn at the edge of the Korabi-Pelagonian platform carbonates on the east (Fig. 2). Some researchers have suggested that the NE-trending Mirdita zone may represent a paleo-oceanic transform fault zone within the Pindos basin (Robertson and Shallo, ...
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Suprasubduction zone (SSZ) ophiolites in orogenic belts represent oceanic crust generation in subduction rollback cycles during the closing stages of basins prior to terminal continental collisions. Oceanic lithosphere created at mid-ocean ridges is generally recycled back into the mantle via subduction, and only rarely do fragments of this MOR lit...
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It is well-documented that Iceland experienced a pulse of elevated volcanism immediately following the last deglaciation (Maclennan et al., 2002). Modeling results suggest ice sheet retreat depressurized the mantle thus enhancing melt production and the supply of magma to the surface (Jull and McKenzie, 1996). Here we take a similar approach, but i...
This study sheds new light on the origin and evolution of the north Kozara ophiolite, a part of the Sava-Vardar Zone. The Sava-Vardar Zone is regarded as a relict of the youngest Tethyan realm in the present-day Balkan Peninsula. The north Kozara ophiolite consists of a bimodal igneous association comprising isotropic to layered gabbros, diabase dy...
Citations
... According to the fifth reconstruction model, all the ophiolites originated from the Pindos Ocean, situated between the Adriatic and Pelagonian continents, and were subsequently emplaced eastward over the western Pelagonian margin (Figure 2.9: e) (e.g., Robertson et al. 1991, Jones et al. 1992, Robertson and Shallo 2000, Karamata 2006, Rassios and Moores 2006, Dilek et al. 2007. The sixth model regards that the Pindos ophiolites originated from the Pindos oceanic basin, situated between the Adriatic and Pelagonian continents. ...
New sedimentological and biostratigraphic research, accompanied by structural analysis, took place on sedimentary successions and mélanges located in northern Greece, both above and below the Jurassic obducted Neo-Tethyan ophiolites. These sedimentary successions and mélanges are associated with Jurassic ophiolite obduction on the Pelagonian margin(s) within the Hellenides. Their study aimed to provide insights regarding the origin of the Neo-Tethyan ophiolites, the timing and direction of their emplacement, the geodynamic evolution of the Neo-Tethys Ocean, and the potential existence of a distinct Pindos Ocean or deep-water Pindos Basin. Important is the occurrence of redeposited Kimmeridgian-Tithonian shallow-water components, as they reveal the existence of a Late Jurassic carbonate platform formed above the obducted ophiolites. This platform set an upper stratigraphic limit for ophiolite emplacement during the Middle to early Late Jurassic. These redeposited components from this shallow-water platform were identified in various successions: 1) Notably, these components are found in redeposited carbonates within Avdella mélange, as well as in Late Jurassic to Earliest Cretaceous carbonate-clastic resediments situated above Koziakas mélange. 2) They are also present within Earliest Cretaceous mass-flows above Vardar-Axios ophiolites. 3) Additionally, they are evident within a late Early Cretaceous transgressive succession above Vourinos ophiolites. Consequently, the identification of Late Jurassic carbonate platform components distributed in different depositional settings associated with ophiolites in both eastern and western regions of the Pelagonian Zone defines a consistent paleogeographic provenance area. This correlation suggests the development of an extensive shallow-water platform sealing the ophiolite emplacement, confirming the presence of a single ophiolite nappe stack. Moreover, microfacies analysis and conodont age dating of exotic carbonate blocks found in the Middle-Late Jurassic Avdella and Koziakas mélanges resulted in the reconstruction of a Middle-Late Triassic open marine shelf. This reconstruction mirrors the Hallstatt Limestone succession and notably shares similarities with successions in western Pindos mountain range, situated to the west of the Pelagonian Zone as part of Pindos Zone, referred to as the Hallstatt/Pindos succession. The original deposition of the Hallstatt Limestones is identified as occurring on the outer shelf from the Middle Triassic until the Early Jurassic, shaping the eastern Adriatic passive continental margin facing the Neo-Tethys Ocean in the east. Structural observations, consistent with other published works, support a west-directed ophiolite emplacement over the eastern passive Pelagonian margin during the Middle-Late Jurassic. Consequently, the Hallstatt/Pindos succession is interpreted as a far-traveled Middle-Late Jurassic nappe, originating from the eastern Pelagonian margin, which was bulldozed in front of the west-directed obducting ophiolites onto the Pelagonian foreland. Therefore, it is concluded that the obducted ophiolites originated from the Neo-Tethys Ocean, positioned to east of the broader Adriatic plate, with the Pelagonian Zone serving as its continuation, without the interruption of a distinct Triassic-Jurassic Pindos Ocean or a Triassic-Jurassic deep-water Pindos Basin.
... All these discrepancies may be ascribed to that the FABs are formed from a prior depletion of their mantle source (depleted MORB source mantle, DMM) compared to the source of N-MORB (Reagan et al., 2010;Ishizuka et al., 2011). Besides, such DMM was barely modified by aqueous fluids or melts released from a subducting slab (Dilek et al., 2007(Dilek et al., , 2008. This is supported by the trace element fingerprints including the depletion in LREEs and LILEs (Fig. 6a, b). ...
... Karaoğlan et al., 2013;Parlak et al., 2019), and extending to Iran and Oman in the east ( Fig. 1; e.g. Garfunkel, 2006;Dilek et al., 2007;Dilek and Furnes, 2019). ...
Ophiolites are remnants of oceanic crust and mantle, now typically found within continental mountain ranges like the Alps. Particularly in areas once part of the Tethys Ocean, ophiolites are often accompanied by narrow stripes of metamorphic rocks, commonly referred to as metamorphic soles. These metamorphic soles typically exhibit peak metamorphic conditions characteristic of either granulite or amphibolite facies. Geochronological studies of Tethyan ophiolites indicate that the development of these metamorphic soles occurred almost simultaneously with the crystallization of the ophiolite’s crustal sequence. Geological evidence also suggests that the metamorphism of the sole rocks took place concurrently with deformation, likely at the same time as the ophiolite’s obduction. In our research, we explore the metamorphic effects of shearing in an ophiolite sequence overlying a crustal sequence. Our findings reveal that strong lithologies like ophiolites can produce additional heat through the dissipation of mechanical energy, which can potentially explain the high temperatures found in metamorphic-sole rocks. In addition, heating-driven softening of the footwall rocks eventually leads to the migration of the active shear zone from the mantle sequence into the upper crustal domain. This migration may be responsible for the metamorphic sole incorporation at the base of the ophiolite. Finally, we demonstrate that stopping the shearing process rapidly cools these rocks, corresponding with the findings from thermochronological studies from Oman ophiolite.
... The Mirdita ophiolite represents a fragment of the Jurassic Neotethyan oceanic lithosphere, which formed in a marginal basin located to the west of the Pelagonian microcontinent (Dilek et al., 2005). Previous research has identified two distinct types of ophiolites in northern Albania based on their unique lithological units, petrology, and geochemical characteristics: the Western (WMO) and Eastern Mirdita ophiolites (EMO) ( Fig. 1) (Hoeck et al., 2002;Dilek et al., 2007Dilek et al., , 2008Saccani et al., 2018 and references therein). The WMO is characterized by a mid-ocean ridge (MOR) geochemical affinity, whereas the EMO exhibits supra- ...
... subduction zone (SSZ) signatures (Hoeck et al., 2002;Dilek et al., 2007Dilek et al., , 2008. The coexistence of both MOR-type and SSZ-type ophiolites in Albania has been attributed to subduction zone initiation magmatism near a mid-ocean ridge (Hoeck et al., 2002), westward-dipping intra-oceanic subduction associated with subsequent rapid slab rollback (Dilek et al., 2008), and some variations of the two (Saccani et al., 2018;Wu et al., 2018). ...
Increasing mineralogical and textural evidence from podiform chromitites in ophiolites suggests their ultra-high-pressure origin (>150 km), challenging conventional models for their formation under low-pressure conditions (<60 km) in the upper mantle. However, this challenge remains controversial due to a lack of in situ mineralogical evidence. Here, we report new data and observations from the Skenderbeu massif in the Mirdita ophiolite, Albania. Transmission electron microscopy shows that these chromitites (Cr# = 41.8-43.2) have numerous exsolution lamellae of diopsidic clinopyroxene and orthoenstatite. These lamellae have a crystallographic topotaxy relationship with the host chromite, i.e. (020) Cpx ∥ (2 20) Chr , (200) Cpx ∥ (111) Chr and (010) Opx ∥ (2 20) Chr , (200) Opx ∥ (2 20) Chr , indicating an exsolution origin. The abundant presence of pyroxene exsolution lamellae in the centre of the host chromites implies the incorporation of Si 4+ and Ca 2+ cations in the precursor chromite, a CaFe 2 O 4-structured high-pressure polymorph that is stable at >12.5 GPa (i.e. 380 km deep). These in situ nanoscale observations and their geological occurrence, together with previously discovered ophiolitic diamonds in the Mirdita ophiolite, suggest a much deeper origin for ophiolitic chromitites than conventional interpretations and provide a valuable opportunity to understand the composition of the deep mantle.
This article is part of the Thematic Collection on: Ophiolites, melanges and blueschists collection available at: https://www. lyellcollection.org/topic/collections/ophiolites-melanges-and-blueschists
... The Mirdita ophiolite, located in northern Albania, represents the relic of the Jurassic Pindos-Mirdita ocean basin [18]. The ophiolite usually be divided into two subunits, the Eastern (EMO) and Western (WMO) Mirdita ophiolite (Figure 1), based on their diagnostic stratigraphy and geochemical characteristics [19][20][21][22]. The lithology of WMO is thin,~3 km thick, and mainly composed of relatively fertile mantle rocks (i.e., lherzoliteharzburgite, plagioclase lherzolite/harzburgite), plutonic intrusions, and extrusive volcanic rocks, whereas the EMO exhibits a more complete ophiolite pseudostratigraphy with a thickness of 10-12 km, and is mainly composed of relatively refractory mantle rocks (i.e., harzburgite, dunite), ultramafic cumulates, plutonic rocks, sheeted dikes, and pillow lavas [18]. ...
... The volcanic rocks of WMO have a mid-ocean ridge (MOR) affinity, which is typical of MOR magmatism. In contrast, the volcanic rocks of EMO show an island arc tholeiite (IAT) signature, which is typical of a suprasubduction zone (SSZ) origin [19][20][21]. Different geodynamic models have been proposed to reconcile the contemporaneous existence of both MOR-type and SSZ-type geochemical affinity within a single ophiolite, such as the two subunit ophiolites formed in separate and discrete tectonic settings [22], subduction established near an active MOR within a same ocean basin [19], and westward-inclined intra-oceanic subduction followed by swift slab rollback [21]. According to the spatialtemporal relationships between mantle and crustal rocks and the time-advancing magmatic evolution of WMO and EMO subunits, a forearc geodynamic model caused by subduction initiation processes is widely accepted [22][23][24]. ...
The ultra-deep genesis of ophiolitic peridotite has reshaped our perception of the genesis of the oceanic mantle. Although ultra-high pressure (UHP) mineral assemblages have been unearthed in dozens of ophiolites in different orogenic belts around the world, the vast majority of them have been limited to podiform chromitites formed in suprasubduction zone (SSZ) settings, leaving uncertainty about whether such UHP minerals are intrinsic to the oceanic mantle or influenced by a specific mantle rock type. Here, we report on the occurrence of diamonds recovered from the harzburgites within the Skenderbeu massif, Mirdita ophiolite. The whole-rock, mineralogical major and trace element compositions, and redox states of the harzburgites align with modern abyssal harzburgites. Trace element modeling of clinopyroxene indicates that harzburgites have endured varying degrees of garnet-facies melting (~2%–5%) before progressing to spinel-facies melting (~10%–12%). Mineralogical characteristics further support that the Skenderbeu harzburgites underwent late-period MORB-like melt metasomatism in a forearc spreading center. An unusual mineral assemblage of diamonds has been separated from the studied harzburgites. The first occurrence of ophiolite-hosted diamonds discovered in the forearc harzburgites, together with previous similar discoveries in the SSZ ophiolitic chromitites, suggest that the ophiolite-hosted diamonds are not specific to certain mantle rocks.
... Ophiolites, as fragments of ancient oceanic lithosphere (e.g. Dewey & Bird, 1971;Coleman, 1977), play irreplaceable roles in the recognition and reconstruction of the evolution history of an ancient ocean, including the opening, closure, development of subduction systems and the consequent orogeny (Dilek, 2003;Dilek et al., 2007;Dilek & Furnes, 2011). Investigation of the formation and emplacement age of an ophiolite can unravel the process of accretionary orogenesis (Xiao et al., 2009a(Xiao et al., , 2013. ...
Typical ophiolitic rock assemblages such as siliciclastic rocks, basalts and gabbros, together with the subduction-related intermediate-acidic intrusive rocks, are newly discovered in the Tongjiang-Fuyuan area of the Heilongjiang Provence, NE China. To determine the formation age and genesis of the mafic rocks (basalts and gabbros) and intermediate-acidic intrusive rocks (granodiorites) in the area, as well as their geodynamic settings, the whole-rock geochemical analysis and zircon LA-ICP-MS U-Pb dating were carried out. Zircon U-Pb results suggest that the granodiorites are 93–95 Ma and gabbro is 95 Ma, respectively. Geochemical results show that the gabbros and basalts exhibit characteristics of ocean island basalt (OIB) affinity and are typically related to having originated from mantle plumes. While the granodiorites show the nature of the island-arc magmatic rocks and may originate from the lower crust. Based on the coeval igneous rock associations and regional tectonic evolution, we conclude that the late Cretaceous magmatic rocks in the Tongjiang-Fuyuan area are the product of continuous subduction of the Palaeo-Pacific plate and reflect the subduction rollback process of the Palaeo-Pacific plate.
... The YZO thus contains wellpreserved Neo-Tethyan oceanic mantle and crustal rocks. The mantle peridotite is dominated by variably serpentinized harzburgite with minor dunite and lherzolite (Girardeau et al., 1985;Hébert et al., 2003;Nicolas et al., 1981) that can provide crucial insights into the evolutionary history of melts, including melting and melt extraction processes and melt-rock interactions (Prinzhofer and Allègre, 1985;Kelemen et al., 1992;Zhou et al., 2005;Arai et al., 2007;Dilek et al., 2007;Ishikawa et al., 2007;Eyuboglu et al., 2010;Dai et al., 2011;Xiong et al., 2017). ...
... This allows us to investigate the possibility of ophiolite obduction under continuous convergence according to geological models (e.g. Dilek et al. 2007;Ghikas et al. 2010). By contrast, the models of Porkoláb et al. (2021) are more similar to ours in the sense that these researchers initially impose continuous convergence. ...
Ophiolite obduction, the process by which part of the oceanic crust overlaps the continental margin, is challenging when it comes to the geodynamic reconstruction of lithospheric processes. This buoyancy difference between dense oceanic crust and the relatively buoyant continental crust makes the obduction of the oceanic crust difficult, if not impossible, when only buoyancy forces are considered. To overcome the difficulties posed by the negative buoyancy, the initial configuration of the oceanic basins must have specific thermal and geometric constraints. Here we present a systematic investigation of the geometrical and the geodynamical parameters which control the ophiolite emplacement process. Our study reveals which parameters are the most important during ophiolite emplacement and which are the most optimal geometries that favour ophiolite emplacement. We focus on “Tethyan” ophiolites which are characterized by relatively small inferred basin size and are commonly found in Mediterranean region. Based on a combination of various parameters, we identified the most susceptible configurations for ophiolite obduction. Our models demonstrate, in agreement to geological data, that the obducted lithosphere must be young and the length of the Ocean-Continent-Transition zone must be relatively sharp in order to achieve ophiolite obduction.
Thematic collection: This article is part of the Ophiolites, melanges and blueschists collection available at: https://www.lyellcollection.org/topic/collections/ophiolites-melanges-and-blueschists
Supplementary material: https://doi.org/10.6084/m9.figshare.c.6922526
... Crucial elements that contribute to this controversial discussion are the ophiolitic mélanges, which are preserved below the obducted ophiolites, and the exotic blocks in these mélanges. The different blocks that originated from the ophiolite suite in the Albanides-Hellenides are fairly well studied and understood (Bortolotti et al. 2004b(Bortolotti et al. , 2013Dilek et al. 2007;Principi et al. 2008;Rassios and Dilek 2009;Robertson 2012, and several others); also, an analysis of the incorporated radiolarite blocks as remnants of the original sedimentary cover of the ocean floor already exists (Chiari et al. 2003;Ozsvart et al. 2012;Gawlick et al. 2016aGawlick et al. , 2017 and provides a good understanding of the life cycle of the obducted oceanic domain from the Late Anisian to Middle Jurassic (e.g. Ozsvart et al. 2012;Gawlick and Missoni 2019, and references therein). ...
... There is still no consensus regarding the timing of the opening of the proposed Pindos Ocean (Cavazza and Wezel 2003, and references therein), although it is considered by many researchers to be a mainly Early Jurassic ocean (Shallo and Dilek 2003;Karamata 2006;Stampfli and Kozur 2006;Robertson 2012, and others;compare Stais andFerriere 1991, 1994;Ferriere et al. 2015Ferriere et al. , 2016. The progressive closure of this ocean should be associated with eastward ophiolite obduction along the western Pelagonian margin, and subsequent tectonic processes would also have led to westward ophiolite emplacement into the involved continental margin (Mountrakis 1986;Robertson et al. 1991;Robertson and Shallo 2000;Karamata 2006;Rassios and Moores 2006;Dilek et al. 2007;Ghikas et al. 2009;Rassios and Dilek 2009;and others). ...
... (2) Kilias et al. (2001Kilias et al. ( , 2010, Gawlick et al. (2008Gawlick et al. ( , 2016aGawlick et al. ( , b, 2017Gawlick et al. ( , 2020 and Missoni and Gawlick (2011); (3) Bernoulli and Laubscher (1972), Aubouin (1973), Dercourt et al. (1986), Schmid et al. (2008), Ferriere et al. (2015Ferriere et al. ( , 2016 and others; (4) Stampfli and Borel (2002), Stampfli and Kozur (2006) and others; (5) Robertson et al. (1991), Jones et al. (1992), Robertson and Shallo (2000), Karamata (2006), Dilek et al. (2007) and others; (6) Mountrakis (1986). (7) Shallo (1991) and others; (8) Shallo and Dilek (2003) and others; (9) Smith and Spray (1984); (10) Robertson (2012). ...
Microfacies analysis and conodont dating on carbonates associated with the Vourinos-Pindos ophiolite emplacement on the Pelagonian unit in northern Greece, combined with structural analysis, enhance our understanding of the palaeogeography and geotectonic evolution of the Hellenides. We focus on a dismembered Triassic Hallstatt Limestone succession incorporated as blocks in the Middle-Late Jurassic Avdella ophiolitic mélange, which is identical to a Triassic succession in the western Pindos (Hallstatt/Pindos succession). Initially, the Hallstatt/Pindos succession was deposited on the outer shelf along the eastern Pelagonian margin and later incorporated into the mélange during west-directed obduction processes.
During the Middle to early Late Jurassic, ophiolites obducted on the eastern Pelagonian margin, resulting in a nappe stack in front of the ophiolites in the lower plate position. Newly formed trench-like basins in front of the advancing nappe stack became filled with sedimentary mélanges, consisting of ophiolitic material mixed with blocks from the Hallstatt/Pindos succession, deposited in an outer shelf position. Subsequently, the Pindos ophiolites overthrust their foreland basin, forming a typical ophiolitic mélange (Avdella mélange). Consequently, the Triassic-Middle Jurassic Hallstatt/Pindos succession represents a far-traveled Middle-Late Jurassic nappe deriving east of the Pelagonian unit, which was bulldozed westward in front of the west-directed obducting Neotethys ophiolites.
... S1 represents a calculated plagioclase lherzolite MORB source comprised 0.60 oli + 0.20 opx + 0.10 cpx and S2 represents the residue (residual source), subsequent to 20% melt extraction from S1. The fields of MORB and VAB are from Pearce (1982), and the BON field is from Dilek et al. (2007). ...
