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We report paleomagnetic data showing that an intraoceanic Trans- Tethyan subduction zone existed south of the Eurasian continent and north of the Indian subcontinent until at least Paleocene time. This system was active between 66 and 62 Ma at a paleolatitude of 8.1 ± 5.6 °N, placing it 600–2,300 km south of the contemporaneous Eurasian margin. The first ophiolite obductions onto the northern Indian margin also occurred at this time, demonstrating that collision was a multistage process involving at least two subduction systems. Collisional events began with collision of India and the Trans-Tethyan subduction zone in Late Cretaceous to Early Paleocene time, followed by the collision of India (plus Trans-Tethyan ophiolites) with Eurasia in mid-Eocene time. These data constrain the total postcollisional convergence across the India–Eurasia convergent zone to 1,350–2,150 km and limit the north–south extent of northwestern Greater India to <900 km. These results have broad implications for how collisional processes may affect plate reconfigurations, global climate, and biodiversity.

This contribution provides insights into ocean-floor hydrothermal metamorphism of the fast-evolving Dinaridic Neotethys. Mineralogical, geochemical and Sr isotope data collected from altered ophiolites and non-ophiolite basalts/andesites and tuffs of the active continental margin are consistent with hydrothermal alteration trajectories that reflect the host-rock composition. This suggests that hydrothermal fluxes were restricted within a simple closed seawater-fed system. Based on the initial isotopic ratios of Sr, two fluid–rock interaction trends are established: (a) low-to-medium degrees of metasomatism in pre-Middle Jurassic anorogenic ophiolites that progressively abated, and (b) increased intensities of metasomatism in post-Middle Jurassic orogenic ophiolites. This agrees with chlorite thermometry and Ca-Al-(Fe)-silicate phase chemistry. The metamorphic assemblages belong to the zeolite, prehnite-pumpellyite, prehnite-actinolite and greenschist facies. The facies is reliant on the temperature of hydrothermal systems and their fluid chemistry. Rare earth element (REE) phase geochemistry shows (a) variable fluid–rock ratios in chlorite and pumpellyite dependent on fluid temperatures, (b) prominent Eu and Ce anomalies that reflect the fluid oxidation state, (c) light REE/heavy REE mobilization attributed to prevalent ligand complexation, and (d) multi-phase fluid percolation across reaction zones of heterogeneous permeability. This study proposes initiation of simple hydrothermal system(s) at or near a spreading centre(s) in the infancy of the Dinaridic Neotethys. Such a system became more complex during Middle Jurassic and Early Cretaceous time with reactive hydrothermal fluids passing the recharge area and reaching the hot reaction zone. An abrupt obliteration of the established high-temperature regime ensued, following the final closure of the Neotethys.

Alternative reconstructions of the Jurassic northern extent of Greater India differ by up to several thousand kilometers. We present a new model that is constrained by revised seafloor spreading anomalies, fracture zones and crustal ages based on drillsites/dredges from all the abyssal plains along the West Australian margin and the Wharton Basin, where an unexpected sliver of Jurassic seafloor (153 Ma) has been found embedded in Cretaceous (95 My old) seafloor. Based on fracture zone trajectories, this NeoTethyan sliver must have originally formed along a western extension of the spreading center that formed the Argo Abyssal Plain, separating a western extension of West Argoland/West Burma from Greater India as a ribbon terrane. The NeoTethyan sliver, Zenith and Wallaby plateaus moved as part of Greater India until westward ridge jumps isolated them. Following another spreading reorganization, the Jurassic crust resumed migrating with Greater India until it was re‐attached to the Australian plate ∼95 Ma. The new Wharton Basin data and kinematic model place strong constraints on the disputed northern Jurassic extent of Greater India. Late Jurassic seafloor spreading must have reached south to the Cuvier Abyssal Plain on the West Australian margin, connected to a spreading ridge wrapping around northern Greater India, but this Jurassic crust is no longer preserved there, having been entirely transferred to the conjugate plate by ridge propagations. This discovery constrains the major portion of Greater India to have been located south of the large‐offset Wallaby‐Zenith Fracture Zone, excluding much larger previously proposed shapes of Greater India. Key Points To constrain the extent of Greater India using evidence offshore West Australia To develop a model that incorporates the new Jurassic data off NW Australia To link the Jurassic and Cretaceous spreading corridors of NW Australia

The distribution of oceanic domains and continental blocks in Central Anatolia remains a challenge in understanding the Alpine geodynamic evolution of the Tethys realm. The consumption of a Neotethys oceanic branch at the Mesozoic‐Cenozoic boundary welded the Central Anatolian Crystalline Complex in central Turkey and the Anatolide‐Tauride Block in western Turkey, with the northerly Eurasian margin. Whether those two regions constituted a single or two distinct continental masses is still matter of debate. High‐pressure metamorphism has been locally evidenced in the Afyon Zone, which was, however, defined as a greenschist‐facies metamorphic zone of the Anatolide‐Tauride Block. Since the Afyon Zone composes a metamorphic equivalent of a continental margin exposed far south of the Izmir‐Ankara suture zone, this encouraged us to reevaluate its metamorphic evolution in order to better understand the relation between western and central Turkey. Our investigations reveal that the high‐pressure minerals Fe‐Mg‐carpholite and glaucophane are present in the entire Afyon Zone, which we reconsider as a blueschist‐facies zone. We additionally present a tectonic reconstruction, stripping off the postcollisional tectonics. It reveals that today's bending of the high‐pressure belt is consistent with an Eocene collision of the Anatolide‐Tauride Block around the southern edge of the Central Anatolian Crystalline Complex. We argue that the Central Anatolian Crystalline Complex and the Anatolide‐Tauride Block were two distinct continental masses separated by a Neotethyan oceanic stripe, the closure of which engendered subduction‐related metamorphism in the latter and arc volcanism and high‐grade metamorphism in the former by late Cretaceous to early Cenozoic.

The Late Cretaceous global transgression is one of the best documented episodes of continental submergence events. The extent of transgression of the Neotethys Ocean into the African continent is generally thought to be limited to north Africa. Here, we describe transgression traces in the Muglad Basin in central Africa that indicate a greater spatial extend of the Neotethys during the late Cretaceous. A series of molecular markers detected in the Upper Cretaceous Santonian-Maastrichtian sediments of the Muglad Basin are typical for marine depositional conditions and differ from those in the typical lacustrine sediments of the Lower Cretaceous Barremian-Aptian. Combining the geological-geochemical implications of these markers with the paleogeographic, paleontological and lithological records, we propose that the Muglad Basin received intermittent marine inundations during the Santonian-Maastrichtian stages (86.3–66.0 Ma) and these special molecular markers are therefore the products of seawater incursion. Consequently, this study proposes that the transgression extent of the Neotethys Ocean into the African continent southern extended to the central Africa during the Late Cretaceous.

Collision between the Pontides and Anatolide‐Tauride Block along the İzmir‐Ankara‐Erzincan suture in Anatolia has been variously estimated from the Late Cretaceous to Eocene. It remains unclear whether this age range results from a protracted, multi‐phase collision or differences between proxies of collision age and/or along strike diachroneity. Here, we leverage the Cretaceous‐Eocene evolution of the forearc‐to‐foreland Central Sakarya Basin system in western Anatolia to determine when and how collision progressed. New detrital zircon (DZ) and sandstone petrography results indicate that the volcanic arc was the main source of sediment to the forearc basin in the Late Cretaceous. The first appearance of Pontide basement‐aged DZs, in concert with exhumation of the accretionary prism and a decrease in regional convergence rates, indicates intercontinental collision initiated no later than 76 Ma. However, this first contractional phase does not produce advanced thick‐skinned deformation and basin partitioning until ca. 54 Ma. We propose three non‐exclusive and widely applicable mechanisms to reconcile the observed ∼20 Myr delay between initial intercontinental collision and thick‐skinned upper plate deformation: slab breakoff, relict basin closure north and south of the İAES, and underthrusting of progressively thicker passive margin lithosphere. These mechanisms highlight the links between upper plate deformation and plate coupling during continental collision. Plain Language Summary Key to understanding the interconnectedness of Earth's systems is unraveling feedbacks between climate, biology, and tectonic plate movements. This can only be resolved within a robust timeframe of tectonic events, including the collision of continents. Yet, the timing of collisions is difficult to determine. We present results from western Turkey where the history of oceanic basin closure and collision from 110 to 40 million years ago (Ma) is preserved in the sedimentary rock record. We identify three phases of oceanic closure (subduction) and continental collision. Subduction was active from at least 110 Ma through 76 Ma when sediment was derived from active volcanoes. At 76 Ma, continental deformation uplifted and eroded older rocks; this is the initial contact between colliding continents. The next phase of collision began at 54 Ma when continental deformation separated the zone of sediment deposition into two basins. The 20‐million‐year collision duration can be explained by three changes to tectonic plate coupling. Together, we conclude that collision age discrepancies are representative of collision mechanics not a function of ill‐fit comparisons between proxies. This long history of collision illuminates how the movement and amalgamation of small continents aided the migration and evolution of species in the Mediterranean. Key Points Multi‐phase intercontinental collision is identified in western Anatolia by sedimentary basin changes Sedimentary provenance change indicate collision was at 76 Ma, but significant thick‐skinned deformation was delayed until 54 Ma The 20 Myr duration of initial collision can be explained by three multi‐stage mechanisms involving changes in plate coupling

Different models have been proposed for the formation and tectonic evolution of the South China Sea (SCS), including extrusion of the Indochina Peninsula, backarc extension, two-stage opening, proto-SCS dragging, extension induced by a mantle plume, and integrated models that combine diverse factors. Among these, the extrusion model has gained the most attention. Based on simplified physical experiments, this model proposes that collision between the Indian and Eurasian Plates resulted in extrusion of the Indochina Peninsula, which in turn led to opening of the SCS. The extrusion of the Indochina Peninsula, however, should have led to preferential opening in the west side of the SCS, which is contrary to observations. Extensional models propose that the SCS was a backarc basin, rifted off the South China Block. Most of the backarc extension models, however, are not compatible with observations in terms of either age or subduction direction. The two-stage extension model is based on extensional basins surrounding the SCS. Recent dating results indeed show two-stage opening in the SCS, but the Southwest Subbasin of the SCS is much younger, which contradicts the two-stage extension model. Here we propose a refined backarc extension model. There was a wide Neotethys Ocean between the Australian and Eurasian Plates before the Indian-Eurasian collision. The ocean floor started to subduct northward at ~125 Ma, causing backarc extension along the southern margin of the Eurasian Plate and the formation of the proto-SCS. The Neotethys subduction regime changed due to ridge subduction in the Late Cretaceous, resulting in fold-belts, uplifting, erosion, and widespread unconformities. It may also have led to the subduction of the proto-SCS. Flat subduction of the ridge may have reached further north and resulted in another backarc extension that formed the SCS. The rollback of the flat subducting slab might have occurred ~90 Ma ago; the second backarc extension may have initiated between 50 and 45 Ma. The opening of the Southwest Subbasin is roughly simultaneous with a ridge jump in the East Subbasin, which implies major tectonic changes in the surrounding regions, likely related to major changes in the extrusion of the Indochina Peninsula.

Middle-Late Jurassic Cimmerian events in Turkey have been actively discussed in the past three decades, but proposed tectonic models associated with magmatism, metamorphism, and stratigraphic features remain controversial. To address this issue, Upper Jurassic mafic lavas are investigated at three locations (Alucra, Gümüşhane, and Olur) in the eastern Sakarya Zone, northeastern Turkey. These lavas are submarine and form planar flows parallel with the bedding plane in the Upper Jurassic carbonate sequence near the base or just below in the clastic sedimentary rocks. The basaltic lavas show calc-alkaline features and possess Nb-Ta values and Nb/U, Nb/La, and Ce/Pb ratios that are greater than those of island arc basalts. Multielement patterns are almost hump shaped, similar to ocean island basalts, which experience Pb depletion and weak negative Nb-Ta, Zr-Hf, and Ti anomalies. The low initial (87Sr/86Sr) ratios (0.70372–0.70554), positive initial εNd values (+2.7 to +4.4), and initial Pb isotope ratios that plot between mid-ocean-ridge and ocean island basalts are consistent with a melt derived from subcontinental lithospheric mantle, metasomatized by earlier fluids from subducted sediments and plume materials from the asthenosphere. Moderate Dy/Yb ratios with an average value of 1.8 imply partial melting in the spinel-garnet transition zone at depths of ∼70–100 km. Slab breakoff is suggested as a geodynamic mechanism that accounts for these geochemical signatures. This inference is also favored by stratigraphic and sedimentologic evidence from the Upper Jurassic–Lower Cretaceous sedimentary rocks, which is consistent with short-lived vertical (epirogenic) movements in the region. Lower-Middle Jurassic sequences are transgressive, suggesting that subduction-related extension opened a backarc basin (Neotethys) in the south of the Sakarya Zone. Upper Jurassic–Lower Cretaceous carbonates point tectonically to tranquility during carbonate deposition in the Neotethys Ocean, which seems to have been achieved by complete closure of the Paleotethys in the north. About 15–20 m.yr. later (Kimmeridgian), after first carbonate deposition, intraplate-type mafic lavas ascended up to the shelf surface of the Neotethys. This was followed by formation of disconformity surfaces and then accumulation of coarse clastic sediments. All this points to a short-lived epirogenic movement that we ascribe to the breakoff of the southward-subducting Paleotethyan oceanic lithosphere in the Late Jurassic.

In the Cenomanian, the southern passive margin of the Neotethys Ocean was dominated by a giant carbonate factory. This succession is known as Sarvak Formation, a significant reservoir in Iran. This study focuses on a detailed analysis of facies variations and paleoenvironmental reconstruction, including the interpretation of the platform types, during this time interval. Based on field observations and petrographical studies, 12 facies have been recognized and ascribed to six facies belts on a carbonate ramp. Sub-environments include the outer ramp and basin (distal open marine), talus and channel (mid-ramp) and lagoon and shoal (inner-ramp). The frequency of the facies and isochore maps indicate the paleoenvironmental conditions and their spatial variations in the study area. Based on all data and analyses, the suggested conceptual model for the Sarvak Formation in the Lurestan Zone is an isolated platform surrounded by two ramps. The upwind and downwind parts of these ramps were located in the central and northern sub-zones of the Lurestan Zone. This model can be used as a template for isolated platforms worldwide.

Carboniferous-to-Triassic sediments and volcanics of the External Hellenides were deposited in different environments of the Paleotethys realm: a back-arc setting along the active margin of Eurasia (Tyros Unit), and a passive margin setting along northern Gondwana/Cimmeria (Phyllite–Quartzite Unit s.str.). The volcanosedimentary records and the age spectra of detrital zircons of both units suggest that their different settings persisted until the Anisian, as long as the Paleotethys was open, but approximated in Ladinian times, when both units collided and the Paleotethys was closed. We present provenance data of post-collisional sediments, a Norian quartzite of the Tyros Unit (Toplou Beds) and a Norian (meta)conglomerate of the Phyllite–Quartzite Unit s.str. (Mana Beds). The type of clastic grains and the ages of detrital zircons indicate a similar source of both units dominated by (1) Cryogenian and Tonian/Stenian basement, (2) low-grade Cadomian basement, and (3) Ladinian/Carnian magmatic rocks. The Carnian zircons in the Norian Tyros Unit (223 ± 7 Ma) and in the Norian Phyllite–Quartzite Unit s.str. (223 ± 5 Ma) are strong evidence that the basins of both units were situated close together. Subsequent to Ladinian collision, the Carnian-to-Norian strata of both units were deposited in adjacent interrelated shallow-marine-to-lacustrine basins, the deposits of which are characterized by black shales, reddish bauxite-type pisolites, and badly sorted sandstones/conglomerates supplied from nearby pre-Ordovician East Gondwana-derived basement. The Variscan basement towards the north was largely drowned in Upper Triassic times as is indicated by only few Variscan-aged zircons in the Carnian/Norian Tyros rocks.