Search

The evolution of the Apennine wedge has seen the time‐space migration of the forebulge, foredeep, thrust wedge, and back‐arc extension phases in the wake of the Eastward rollback of the subducting Adria slab. In this framework, thrusting and post‐orogenic extensional faulting have occurred in two parallel forelandward‐migrating ribbons, with extensional deformation overprinting or partly exploiting anisotropies of the inherited thrust system. Here, we explore the tectonic framework and the timing of thrusting and subsequent negative inversion of the Circeo thrust, one of the major thrusts in the inner portion of the central Apennines, with the main aim to constrain the timing and mode of the compression to extension switch. Structural analysis, carbonate C and O and clumped isotopes analysis, X‐ray diffraction of clay minerals, and U‐Pb dating of calcite slickenfibers have been integrated with seismic interpretation, cross‐section balancing, and 1D burial and thermal modeling. We show that the Circeo thrust developed during Langhian‐Serravallian time. Its extensional reactivation is dated at the Serravallian, during the stacking of an underlying thrust slice, before the onset of Pliocene back‐arc extension in the area. Combination of our data with the age of thrusts, extensional basins, and base of the foredeep infill of the central Apennines, demonstrates that forelandward migration of the foredeep‐thrust system occurred at variable velocities. Accelerations and decelerations are synchronous, respectively, with the opening of the Liguro‐Provençal and Tyrrhenian back‐arc basins and with the interluding quiescent period. Key Points: We build a balanced cross section across the Circeo thin‐skinned thrust, one of the innermost structures of the central ApenninesThe section is validated by means of carbonate C and O and clumped isotopes, U‐Pb dating, seismic interpretation and burial modelingA regional synthesis of the age of foredeep infill, thrusts, and extensional basins for the central Apennines is presented [ABSTRACT FROM AUTHOR]

Post‐orogenic back‐arc magmatism is accompanied by hydrothermal ore deposits and mineralizations derived from mantle and crustal sources. We investigate Zannone Island (ZI), back‐arc Tyrrhenian basin, Italy, to define the source(s) of mineralizing hydrothermal fluids and their relationships with the regional petrological‐tectonic setting. On ZI, early Miocene thrusting was overprinted by late Miocene post‐orogenic extension and related hydrothermal alteration. Since active submarine hydrothermal outflow is reported close to the island, Zannone provides an ideal site to determine the P‐T‐X evolution of the long‐lived hydrothermal system. We combined field work with microstructural analyses on syn‐tectonic quartz veins and carbonate mineralizations, X‐ray diffraction analysis, microthermometry and element mapping of fluid inclusions (FIs), C, O, and clumped isotopes, and analyses of noble gases (He‐Ne‐Ar) and CO2 content in FIs. Our results document the evolution of a fluid system of magmatic origin with increasing mixing of meteoric fluids. Magmatic fluids were responsible for quartz veins precipitation at ∼125 to 150 MPa and ∼300°C–350°C. With the onset of extensional faulting, magmatic fluids progressively interacted with carbonate rocks and mixed with meteoric fluids, leading to (a) host rock alteration with associated carbonate and minor ore mineral precipitation, (b) progressive fluid neutralization, (c) cooling of the hydrothermal system (from ∼320°C to ∼86°C), and (d) embrittlement and fracturing of the host rocks. Both quartz and carbonate mineralizations show noble gases values lower than those from the adjacent active volcanic areas and submarine hydrothermal systems, indicating that the fossil‐to‐active hydrothermal history is associated with the emplacement of multiple magmatic intrusions. Key Points: Deciphering the fossil‐to‐active hydrothermal system on Zannone Island in which magmatic and meteoric fluids mixedPolyphase and long‐lived hydrothermal activity associated with mantle‐ and crustal‐derived magmasFluid mixing and fluid‐rock interaction led to fluid neutralization, cooling, embrittlements, alteration, and minor ore minerals [ABSTRACT FROM AUTHOR]

The Tyrrhenian back‐arc basin developed at the rear of the E‐ward migrating Apennine fold‐and‐thrust belt, with northward decreasing rollback of the subducting Adria slab leading to northward fading of back‐arc extension. The northern portion of the Tyrrhenian basin is made of thinned continental crust, whereas in the central/southern portion extension eventually evolved to oceanic crust production. In this framework, a long‐lasting debate concerns the existence of a >200 km long transform zone along the 41st parallel, which should separate the two portions of the Tyrrhenian basin. At its eastern termination, a branch of the presumed transform zone enters the Tyrrhenian margin of the Apennine belt and occurs as an accommodation zone made of a ribbon of extensional faults and related basins. This accommodation zone, which separates areas of mutually perpendicular extension directions, is here introduced, described, and named the Ponza‐Alife accommodation zone. Interpretation of seismic lines and new structural and stratigraphic data from this accommodation zone have been used to constrain the pre‐orogenic and syn‐orogenic architecture of the subducting plate and the Plio‐Quaternary back‐arc extensional stage. Our data indicate that the studied zone retraces a deep‐seated transform fault system located in the subducting plate and inherited from an Early Jurassic rifting episode, which caused the lateral juxtaposition of different rift domains in the subducting plate. We propose that during collision and trench retreat, this lateral juxtaposition has controlled differential retreat of the subducting plate across the studied zone, forcing the development of the Ponza‐Alife accommodation zone in the overlying back‐arc basin's margin. Key Points: The Ponza‐Alife accommodation zone segmenting the Apenninic margin of the Tyrrhenian back‐arc basin is introducedStructural and stratigraphic data, and seismic interpretation allowed us to unravel the evolution of this accommodation zoneThe accommodation zone originated from tearing in the downgoing plate reworking Jurassic faults that segmented the associated rift system [ABSTRACT FROM AUTHOR]

The Adria microplate is the foreland of the oppositely verging Apennines and Alps or Dinarides fold‐thrust belts associated to the related subduction zones. Along its western margin, the Adria plate hosts the active Northern Apennines accretionary prism, which is buried under the Adriatic Sea and the Po Plain. The interpretation of seismic reflection profiles and borehole data allowed us to define the geometry of the transition from the Apennines fold‐thrust belt to its undeformed foreland. Moreover, continuous GPS (CGPS) data from offshore hydrocarbon platforms anchored to the seabed of the northern Adriatic plate allow to measure present‐day kinematics. Although the CGPS signals are affected by non‐tectonic components associated with hydrocarbon extraction, the integration of geodetic analysis, subsurface geological reconstructions, and analytical modeling allowed us to constrain the ongoing tectonic activity. Shortening is currently accommodated by aseismic slip along the basal detachment, likely accumulating elastic energy along the frontal ramp that may eventually seismically slip. Our multidisciplinary study suggests that the study area may not be sheltered from relevant seismic sequences similar to the Mw 6 Emilia 2012 events and that the occurrence of potential seismogenic sources in the area should be carefully evaluated. Similar studies may be useful to constrain the present‐day activity in other marine areas and to identify potential and hitherto unrecognized seismogenic sources along the entire Apennines belt and other accretionary prisms worldwide. Key Points: Seismic reflection profiles in the northern Adriatic Sea allow to reconstruct the Apennines fold‐thrust belt geometry and its forelandOffshore CGPS data allow computation of the active shortening in the accretionary prismAnalytical modeling provides a first‐order estimation of the current slip rate of the unlocked and locked surfaces of the basal decollement [ABSTRACT FROM AUTHOR]

The Oman Mountains expose Permo‐Mesozoic shelf rocks of Arabia overridden by continental slope/basinal sediments and Semail Ophiolites during Late Cretaceous. A major syntaxis is represented by the Musandam Peninsula and Dibba Zone. The overthrusting of allochthonous units onto the Musandam shelf carbonates initiated during the Cenomanian. Structural analyses in the Musandam Peninsula constrained top‐to‐the‐west thrusting that took place 74–60 Ma ago (U‐Pb datings of synkinematic calcites), about 15–30 Ma after the obduction of the Semail Ophiolite. The Dibba faults exhibit a first interval of thrusting (top‐to‐the‐west) followed by dextral slip. We propose that SW vergent thrusts, initially parallel to those of the Central and Southern Oman Mountains, were subsequently rotated to their present‐day NE‐SW strike during the development of the syntaxis and then reactivated by dextral slip. Mixed layers illite‐smectite (I‐S) constrain the thermal evolution of the passive margin sequence and of the allochthonous deep‐water sediments. In particular, the proximal Hawasina unit (Hamrat Duru) and Sumeini groups of the Dibba Zone are characterized by long‐range ordered mixed layers I‐S with an illite content of 90–95%, whereas Musandam carbonate units show mixed layers I‐S with illite layers ranging from 80–90%, indicating deep diagenetic conditions. Such levels of thermal maturity were acquired during the Late Cretaceous emplacement of a 3.5‐km‐thick pile of allochthonous units, which were removed by erosion and denudation since the Campanian. U‐Pb dating of synkinematic calcite vein highlights reactivation of thrusts at 13.2 Ma, likely due to the involvement of the Musandam area in the Arabia‐Eurasia collision. [ABSTRACT FROM AUTHOR]

Thrust fault ruptures during earthquakes do not often propagate down to the brittle‐ductile transition. Lithological variations control the behavior and depth of regional basal thrusts and decollement planes. Thrust fronts may be discontinuous along strike, limiting the dimension of single coseismic ruptures. These factors control the maximum expected magnitude in one region. This is the case of Italy where the convergence of few millimeter per year in the Apennines accretionary prism and along the retrobelt of the Alps generates compressional earthquakes with moderate to strong magnitudes. Here, using geological and geophysical data, we first compile a map of the undulated active basal thrust decollement for Italy that occurs from 1 to 17‐km depth. Then, we verify the relationship between the length of seismogenic ruptures in thrust faults (Lf) and the maximum depth of thrust faulting (zmax) of related earthquakes and find that their ratio (Lf/zmax) ranges between 2 and 4. Finally, we compute the potential seismogenic volume and estimate the maximum magnitude using an empirical relationship that multiplies the decollement depth and the Lf/zmax ratio. Maximum calculated magnitude is 6.7 ± 0.37 (depending on Lf/zmax and fault dip angle), consistent with the largest magnitude of thrust‐related earthquakes recorded in Italy (6.5–7.0). Lower magnitudes are predicted in the Ionian Seas at the external front of the Apennines where smaller crustal volumes are involved, whereas higher magnitudes are expected in the southern Po Basin, the western Adriatic Sea, Sicily offshore, and the Southern Alps where the decollement is deeper and the brittle volumes are far greater. Plain Language Summary: Earthquakes are due to different kinds of crustal fault ruptures, and the observed magnitude depends on the rupture dimension, hence on the involved brittle volume. Those related to thrust faults generate magnitudes lower than expected if the decollement is shallow, whereas the magnitudes increase where the decollement is deeper. This is the case of Italy where many factors can explain the moderate to strong (M 5–7) observed magnitudes recorded so far in the contractional areas of the country: (i) the slow convergence rate (few millimeters per year) observed for the Apennines and Alps; (ii) the thrusts do not cut down the entire seismogenic crust; and that (iii) thrusts are undulated and segmented along strike, limiting the dimension of the fault rupture. We compile a map of the thrust decollement depth for Italy that is situated between 1–17 km. Then, we quantify the along‐strike discontinuity, verifying the ratio between thrusts length and faulting depth of related earthquakes. Finally, we estimate the maximum expected magnitude for the study area. Calculated magnitudes are consistent with those occurred for thrust‐related earthquakes in Italy, pointing to the importance of knowing the depth and the lateral continuity of faults to correctly assess the seismic potential of a region. Key Points: The basal active thrust decollement is mapped on the Italian accretionary prismsWe define the relationship between the length of thrusts ruptures and maximum faulting depth (Lf/zmax) for Italian earthquakesSeismic volumes calculated from faulting depth and Lf/zmax ratio provide a good estimation of expected magnitudes [ABSTRACT FROM AUTHOR]

Numerical models were used to investigate the effects of differential compaction on strain development and early fracturing in an early cemented high-relief Triassic carbonate platform prograding onto basinal sediments, whose thickness increases basinward. Results show that basinal sediment compaction induces stretching of internal platform and slope strata in prograding platforms. When sediments are early cemented, such extensional strain is accommodated by the generation of syndepositional fractures. The amount of stretching is predicted to increase from the oldest to the youngest layers, due to the thickening of the compactable basinal sequences towards the external parts of the platform. Stretching is also controlled by the characteristics of the basin: the thicker and the more compactable the basinal sediments, the larger will be the stretching. Numerical modelling has been applied to the Ladinian- Early Carnian carbonate platform of the Esino Limestone ( Central Southern Alps of Italy). This case study is favourable for numerical modelling, as it is well exposed and both its internal geometry (inner platform, reef and prograding clinostratified slope deposits) and the relationship with the adjacent basin can be fully reconstructed, as the Alpine tectonic overprint is weak in the study area. Evidence for early fracturing (fractures filled by fibrous cements coeval with the platform development) is described and the location, orientation and width of the fractures measured. The fractures are mainly steeply dipping and oriented perpendicularly to the direction of progradation of the platform, mimicking local platform-margin trends. The integration of numerical models with field data gives the opportunity to quantify the extension triggered by differential compaction and predict the possible distribution of early fractures in carbonate platforms of known geometry and thickness, whereas the interpretation of early fractures as the effects of differential compaction can be supported or rejected by the comparison with the results of ad hoc numerical modelling. [ABSTRACT FROM AUTHOR]

A structural, petrological and geochronological (U-Th-Pb of zircon and monazite) study reveals that the lower crust sequences of the Variscan high-grade basement cropping out between Solenzara and Porto Vecchio, south-east Corsica (France) have been tectonically juxtaposed along with middle crustal rocks during the extrusion of the orogenic root of the Variscan chain. We propose that a system of high-temperature, orogen-parallel shear zones that developed under a transpressive dextral tectonic regime caused the exhumation of the entire sequence. This tectonic complex is thus made up of rocks having undergone different P–T conditions (eclogite-?, high-pressure granulite facies and amphibolite facies) at different times, reflecting the progressive foreland migration of the orogenic front. The Solenzara granulites were derived from burial of continental crust to high-pressure (1.8–1.4 GPa) and high- to ultrahigh-temperature conditions (900–1000 °C) during the Variscan convergence: U–Pb ELA-ICPMS zircon dating constrained the timing of this metamorphism at c. 360 Ma. The gneisses cropping out at Porto Vecchio are middle crustal-level rocks that reached their peak temperature conditions (700–750 °C at <1.0 GPa) at c. 340 Ma. The diachronism of the metamorphic events, the foliation patterns and their geometry suggest that the granulites were exhumed to middle crustal levels through channel flow tectonics under continuous compression. The amphibolite facies gneisses of Porto Vecchio and the granulites of Solenzara were accreted through the development of a major dextral mylonitic zone forming under amphibolite facies conditions: in situ monazite isotope dating (ELA-ICPMS) revealed that this deformation occurred at c. 320 Ma and was accompanied by the emplacement of syntectonic high-K melts. A final HTLP static overprint, constrained at 312–308 Ma by monazite U-Th-Pb isotope dating, is related to the emplacement of the igneous products of the Sardinia-Corsica batholith and marks the transition from the Variscan orogenic event to the Permian extension. [ABSTRACT FROM AUTHOR]

Secondary acute myeloid leukemia (s-AML) is associated with inferior outcomes with conventional chemotherapy, and fludarabine combinations (FLAG-Ida) have been tested to improve results. More recently, CPX-351 resulted superior to conventional 3 + 7 in s-AML patients. In the UK NCRI AML19 trial, AML patients were randomized to receive either FLAG-Ida or CPX-351. Subgroup analysis revealed better overall survival (OS) with CPX-351 in patients with MDS-related gene mutations. Unfortunately, minimal residual disease (MRD) was evaluated only in a minority of patients. The aim of this study was to further disclose the mechanisms of higher efficacy of CPX-351 in s-AML, with a focus on MRD. We analyzed 183 consecutive s-AML elderly patients (median age 69, range 60-77) treated with CPX-351 (n = 82) or receiving FLAG-Ida (n = 101). Complete remission (CR) rate and MRD negativity probability were higher among patients receiving CPX-351 (MRD negative CR rate of 40/64, 62.5%, compared to 25/55, 45% in patients who received FLAG-Ida, p < 0.05). Extra-hematological toxicity was lower in CPX-351 arm, and 30 days mortality was 3.6% and 8% in patients receiving CPX-351 or FLAG-Ida, respectively. Notably, 21/64 (32.8%) CR patients treated with CPX 351 underwent allogeneic stem cell transplantation (HSCT), compared to 5/55 with FLAG-Ida (9%, p < 0.05). Overall, CPX-351 treatment resulted in higher OS (median OS 17.7 vs. 11.2 months with FLAG-Ida, p < 0.05). The better outcome of CPX-351 compared to FLAG-Ida in our cohort may be explained by a greater probability of MRD negativity, alongside with an improved tolerance, enabling more s-AML patients to undergo HSCT., (© 2024 John Wiley & Sons Ltd.)

During aging, brain performances decline. Cellular senescence is one of the aging drivers and a key feature of a variety of human age-related disorders. The transcriptional repressor RE1-silencing transcription factor (REST) has been associated with aging and higher risk of neurodegenerative disorders. However, how REST contributes to the senescence program and functional impairment remains largely unknown. Here, we report that REST is essential to prevent the senescence phenotype in primary mouse neurons. REST deficiency causes failure of autophagy and loss of proteostasis, increased oxidative stress, and higher rate of cell death. Re-establishment of autophagy reverses the main hallmarks of senescence. Our data indicate that REST has a protective role in physiological aging by regulating the autophagic flux and the senescence program in neurons, with implications for neurological disorders associated with aging., (© 2021 The Authors. Aging Cell published by Anatomical Society and John Wiley & Sons Ltd.)