The Central Taurides represent a high-relief topography with a multi-phase uplift history linked to mantle-driven, deep-seated processes. While the uplift history is well constrained, the temporal relationship between surface uplift and brittle surface deformation is poorly documented. Here, we combine U-Th geochronology, microstructural analysis, and fault-slip data to decipher the timing and mechanism of upper crustal deformation above the Cyprus Subduction Zone, which has experienced 1.5 km of surface uplift since 450 ka. Kinematic measurements indicate widespread normal faulting due to NE-SW horizontal tension in the upper crust. U-Th ages of fault-related calcites show continuous faulting from the Middle/Late Pleistocene to the Holocene, with a conspicuous clustering at circa 450 ka. Our study emphasizes the connection/coupling between deep-seated and surface processes. It suggests that extensional deformation and rapid surface uplift may occur concurrently, creating relief-bounding normal fault zones and high-relief dynamic landscapes on a short timescale in the overriding plates.

A phase of isobaric heating during exhumation of high-pressure rocks is often reported, but the tectonic significance of isobaric heating remains uncertain. Constraining the timescales of isobaric heating is essential for connecting the heating to tectonic processes of lithospheric thickening and extension. An isobaric heating phase has been reported for the Cycladic Blueschist Unit in the Hellenide orogen of Greece. We present diffusion modeling of major elements in garnet using data from Naxos Island to provide new independent estimates of the duration of isobaric heating. We also present radioactive trace element analyses of the Cycladic basement and a heat conduction model to explore the heat production generated in the basement and its influence on isobaric heating. Our model indicates that isobaric heating occurred over ∼9.7 Myr, during which the Cycladic basement generated enough heat to explain the observed temperature increase. At the end of this heating phase, the temperature increase caused a significant drop in crustal strength, which controlled the style of crustal extensional deformation during subsequent rollback of the subducting slab. Our work implies that the underthrusting of radiogenic material in convergent settings produces sufficient heat to significantly increase temperature which weakens the crust and enables pervasive deformation.

The Hohonu Batholith is an aggregation of mostly mid-Cretaceous granitoid plutons on the West Coast of the South Island of New Zealand emplaced during a transitional period between subduction-related compression and continental lithospheric extension. This study reports an integrated dataset, comprising in-situ U-Pb, O and Hf isotope compositions and REE, Ti and other trace and major elements (Zr-Hf, Th-U) for zircons extracted from four representative plutons within the batholith. Our results provide detailed insight into the protracted thermal, chronological and geochemical histories. LA-ICPMS U-Pb zircon ages indicate a primary episode of magma genesis and emplacement from 107 to 113 Ma, confirming published SIMS dating. However, a younger previously unrecognized age population of ∼91–96 Ma is identified, primarily (although not exclusively) in zircon rims. This younger age event coincides with the timing of protracted lithospheric extension and crustal thinning of the Zealandia continent. The cryptic younger zircon ages suggest that Hohonu granitoids experienced a partial thermal overprint (accompanied by Pb loss) mostly recorded in rims. Differences in bulk rock geochemistry between plutons are inferred to reflect variable conditions of partial melting controlled by source mineralogy and H2O content. Isotope and trace element compositions, along with Ti-thermometry, measured on the same micro-volume of CL-imaged zircons, are used to test if source characteristics were imparted from melt to minerals in zircon-saturated silicic systems. Similarities are revealed in the zircon record of the selected plutonic rocks, confirming their broadly consanguineous relationship and the fundamental role of open-system behaviour, involving hybridization or assimilation between mantle-derived (or juvenile mafic) and crustal-derived components, as previously inferred from whole rock Nd-Sr isotope systematics. However, intra-sample decoupling of zircon O-Hf isotope systematics may also be linked to residual source unmixing. This possibility, in addition to mafic recharge, may have obscured melt source compositional characteristics, and hence zircon REE appear as unsuitable fingerprints of source(s) and conditions of partial melting in this granitoid system. Simple compositional and thermal magma evolution trends appear punctuated by episodes of mafic recharge, presumably during lithospheric thinning.

Understanding temporal shifts of thrust transport direction and the interplay between thrusting and normal faulting during mountain building is important for better understanding orogeny. Current tectonic models of the Alps envisage Cretaceous E–W directed thrusting and subsequent extension in the same direction, mainly preserved in the upper plate (Austroalpine unit), followed by Paleogene N–S shortening. The Austroalpine-Pennine boundary region is at the transition between dominantly E–W and N–S directed orogenic movements. This study focuses on metabasite rocks of the Pennine Avers nappe, which retain evidence for early E–W directed shortening extending into the Eocene, thus conflicting with the standard orogenic models. Our new kinematic and geochronological constraints from the Avers nappe demonstrate that top-to-the-W nappe imbrication progressed into the South Pennine realm under blueschist facies conditions. Rb–Sr multimineral isochron ages constrain the waning stages of top-to-the-W shear between 47.26 ± 0.26 and ≥ 43.5 ± 0.6 Ma (2σ uncertainties). Subsequent deformation during incipient decompression from blueschist-facies metamorphism associated with N–S shearing occurred between 41.1 ± 1.7 and 40.7 ± 1.6 Ma. A summary of previously published geochronological and kinematic data shows that Cretaceous to Eocene (until ≥ 43.5 ± 0.6 Ma) deformation is best described by an overcritically tapered orogenic wedge model. The subsequent deep underthrusting and underplating of the distal European margin is considered to have caused a change in orogenic wedge dynamics, leading to extruding wedge tectonics associated with N–S shortening.

Contractional faults and shear zones are often reactivated by normal faulting and the timing of this kinematic switchover is critical for better understanding orogeny, especially the formation and exhumation of high-pressure rocks. We report two fault gouge ages of ∼30 and ∼25 Ma from the contact zone between the high-pressure Phyllite-Quartzite Unit and the overlying, weakly metamorphosed Tripolitza Nappe in central Crete, southern Aegean Sea, Greece. This contact, the Damasta shear zone, is commonly regarded as a segment of the Cretan Detachment, the age of which is not well known. The dated gouge dominantly shows early top-to-the-S kinematic indicators, with some indication of a top-to-the-N reactivation. Illite/muscovite grain-size fractions of 0.5–0.2 μm and 0.2–0.1 μm yielded, within error, similar K[sbnd]Ar ages of ∼30 Ma. These internally consistent ages can be interpreted as the timing of a first faulting event, which we interpret to be associated with the dominant set of top-to-the-S kinematic indicators. Three K[sbnd]Ar ages of ∼25 Ma were obtained from two separate <0.1 μm and a single <0.2 μm grain-size fraction. This robust age of the finest grain-size fractions reflects the final faulting increment, considered to date top-to-the N normal shearing. Because the ∼25 Ma age overlaps with high-pressure metamorphism and subsequent rapid exhumation of the Phyllite-Quartzite Unit, we regard the age to be related to the Cretan Detachment in central Crete. Published data show that the upper parts of the Phyllite-Quartzite Unit started to be underthrust to the north between 36 and 29 Ma. Therefore, we relate the fault gouge ages of ∼30 Ma to this underthrusting event. We conclude that the switchover from contractional to normal faulting on the Cretan Detachment occurred at about 25 Ma.

The geometry of large-scale extensional deformation in the southwestern Cyclades archipelago is a controversially discussed issue. Recent studies suggest a bivergent (i.e., coeval top-to-the-S and top-to-the-N shear) geometry of early Miocene extensional deformation. On Sikinos Island, top-to-the-S shear structures in the Cycladic basement are overprinted by a prominent ductile-to-brittle top-to-the-N extensional shear zone in the Cycladic basement at its contact with the tectonically overlying passive-margin sequence of the Cycladic Blueschist Unit. Hitherto, the top-to-the-S shear structures have been related to thrusting of the passive-margin sequence onto the Cycladic basement. Rb–Sr multimineral dating constrains the age of retrograde, lower greenschist-facies top-to-the-S shearing at 23.20 ± 0.25 Ma. This age is identical to published ⁴⁰Ar/³⁹Ar ages of ~ 23 Ma for a lower greenschist-facies top-to-the-S extensional shear zone on nearby Folegandros Island. Therefore, an interpretation of the top-to-the-S shear zone in the Cycladic basement of Sikinos as resulting from extensional deformation is consistent with the regional scale context of crustal extension invoked for the Cyclades in the early Miocene. On Folegandros Island, top-to-the-S extension occurs at the top of the passive-margin sequence of the Cycladic Blueschist Unit, whereas on Sikinos  coeval top-to-the-S extension occurs near the top of the underlying Cycladic basement. Our new Rb–Sr age of ~ 23 Ma indicates that top-to-the-S fabrics reflect the earliest Miocene extensional structures. They are intimately related to the top-to-the-N extensional structures forming an early Miocene bivergent extensional hinge zone at the southern end of the Cyclades archipelago.

The North Anatolian Fault (NAF), one of the most prominent plate boundary continental fault systems on Earth, facilitates the westward movement of the Anatolian microplate into the Aegean region. The temporal and spatial evolution of the NAF is important for understanding the mechanism of escape tectonics during plate interaction in active orogenic regions. The driving force(s) behind the movement of the NAF and the time period over which this occurred remain controversial. Our U–Pb and K–Ar dating of syntectonic minerals shows that a predecessor faulting initiated as early as ~40 Ma due to shortening along the Neo-Tethyan suture zone. Fault reactivations occurred at ~20 and 10 Ma synchronously in eastern and western Anatolia, suggesting that the NAF already existed by ~20 Ma. Our data also show that the westward motion of Anatolia was not only controlled by the Arabia–Eurasia collision in eastern Anatolia, but also by Aegean extension.

We report three U–Pb sulfate ages from the recently identified Intra-PQ Thrust within the Phyllite–Quartzite (PQ) Nappe of the Ionian high-pressure belt of the external Hellenides in the eastern Mediterranean. Crosscutting relations show that a distinct pressure-solution laminae/microlithon fabric is the oldest deformation structure. Two analyses of sulfate minerals that are part of this structure yielded indistinguishable dates, with a weighted average of 20.03 ± 5.96 Ma. The crosscutting fabric with alteration halos of the sulfate provided a date of 9.37 ± 4.64 Ma. The initial ²⁰⁷Pb/²⁰⁶Pb ratios are ~ 0.40 and thus distinctively lower than the terrestrial model lead isotope ratio of 0.84 for the calculated ages. This can only be explained if the dated sulfate precipitated from a fluid enriched in radiogenic ²⁰⁶Pb, probably sourced by the surrounding country rock through (partial) dissolution of older U-rich minerals. The dates of ~ 20 Ma agree with recently reported fault-gouge ages of 26–21 Ma from the Intra-PQ Thrust. The study demonstrates, for the first time, the possibility of dating sulfate minerals in metamorphosed rocks applying the U–Pb system.

The complex structural geometry along the northern continental margin of Oman formed during polyphase deformation from the mid-Cretaceous to the Miocene. We focus on the kinematics and tectonics of the Wadi Kabir Fault, which represents an eastern segment of the large-scale, composite Frontal Range fault system that forms the northern boundary of the central Al Hajar Mountains. The most exhumed rocks outcrop in the Saih Hatat window of the Al Hajar Mountains, which occurs in the footwall of the Wadi Kabir Fault. To better understand the tectonic history of the Wadi Kabir Fault, we report three K-Ar illite fault-gouge ages. Sample FG16-1 from a shallowly north-dipping gouge zone of the eastern segment of the Wadi Kabir Fault yielded two consistent ages that overlap within 2σ uncertainties at ∼90 Ma. Sample FG16-2 from the central segment of the fault yielded a K–Ar age of 57.9 ± 2.0 Ma (2σ uncertainties), which is interpreted as a late Paleocene faulting event as it perfectly matches the cooling history of the high-pressure rocks of the Saih Hatat window in the footwall of the Wadi Kabir Fault. We present two tectonic interpretations for the ∼90 Ma fault-gouge age and prefer a synchronous kinematic relationship with the parallel and contractional mid-Cretaceous Yenkit Shear Zone that was active at the distal Arabian Platform since 114 Ma. Because the 57.9 ± 2.0 Ma age is associated with pronounced footwall cooling, we interpret this age to be related to the formation of the Bandar Jissah Basin in the hanging wall of the Wadi Kabir Fault. We conclude that the Frontal Range fault system likely formed during the Paleocene and that its young (≤∼43 Ma) history was accommodated along the western segment of the fault, as there is no evidence of this Eocene fault interval at the Wadi Kabir Fault.

The Samail Ophiolite in the Oman Mountains formed at a Cretaceous subduction zone that was part of a wider Neo-Tethys plate-boundary system. The original configuration and evolution of this plate-boundary system is hidden in a structurally and metamorphically complex nappe stack below the Samail Ophiolite. Previous work provided evidence for high-temperature metamorphism high in the nappe pile (in the metamorphic sole of the Samail Ophiolite), and high-pressure metamorphism in the deepest part of the nappe pile (Saih Hatat window), possibly reflecting a downward younging, progressive accretion history at the Samail subduction zone. However, there is evidence that the two subduction-related metamorphic events are disparate, but temporally overlapping during the mid-Cretaceous. We present the first geochronologic dataset across the entire high-pressure nappe stack below the Samail Ophiolite, and the shear zones between the high-pressure nappes. Our 22 new Rb-Sr multimineral isochron ages from the Saih Hatat window, along with independent new field mapping and kinematic reconstructions, constrain the timing and geometry of tectonometamorphic events. Our work indicates the existence of a highpressure metamorphic event in the nappes below the ophiolite that was synchronous with the hightemperature conditions in the metamorphic sole. We argue that the thermal conditions of these synchronous metamorphic events can only be explained through the existence of two Cretaceous subduction zones/segments that underwent distinctly different thermal histories during subduction infancy. We infer that these two subduction zones initially formed at two perpendicular subduction segments at the Arabian margin and subsequently rotated relative to each other and, as a consequence, their records became juxtaposed: (1) The hightemperature metamorphic sole and the Samail Ophiolite both formed above the structurally higher, outboard, 'hot' and rotating Samail subduction zone and, (2) the high-pressure nappes developed within the structurally lower, inboard, 'cold' Ruwi subduction zone. We conclude that the formation and evolution of both subduction zones were likely controlled by the density structure of the mafic-rock-rich Arabian rifted margin and outermost Arabian Platform, and the subsequent arrival of the buoyant, largely mafic-rock-free, full-thickness Arabian lithosphere, which eventually halted subduction at the southern margin of Neo-Tethys.