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An asthenospheric window underneath much of the South American continent increases the heat flow in the southern Patagonian Andes where glacial-interglacial cycles drive the building and melting of the Patagonian Icefields since the latest Miocene. The Last Glacial Maximum (LGM) was reached similar to 26 000 yr BP (years before present). Significant deglaciation onsets between 21 000 and 17 000 yr BP were subject to an acceleration since the Little Ice Age (LIA), which was similar to 400 yr BP. Fast uplift rates of up to 41 +/- 3 mm yr - 1 are measured by global navigation satellite system (GNSS) around the Southern Patagonian Icefield and are currently ascribed to post-LIA lithospheric rebound, but the possible longer-term post-LGM rebound is poorly constrained. These uplift rates, in addition, are 1 order of magnitude higher than those measured on other glaciated orogens (e.g. the European Alps), which raises questions about the role of the asthenospheric window in affecting the vertical surface displacement rates. Here, we perform geodynamic thermo-mechanical numerical modelling to estimate the surface uplift rates induced by post-LIA and post-LGM deglaciation, accounting for temperature-dependent rheologies and different thermal regimes in the asthenosphere. Our modelled maximum post-glacial rebound matches the observed uplift rate budget only when both post-LIA and post-LGM deglaciation are accounted for and only if a standard continental asthenospheric mantle potential temperature is increased by 150-200 degrees C. The asthenospheric window thus plays a key role in controlling the magnitude of presently observed uplift rates in the southern Patagonian Andes.

We investigate the Palaeocene succession of the Hazara Basin (Northern Pakistan) to better understand the impact of climate change on marine carbonate-producing organisms. These shallow-water carbonates, deposited during the Late Palaeocene, before the onset of the Palaeocene-Eocene Thermal Maximum, were studied using a quantitative approach to highlight changes in the skeletal assemblage. We recognise a decrease in the abundance of colonial corals and green calcareous algae and an increase in larger benthic foraminifera and red calcareous algae from the early Thanetian to the late Thanetian. Increasing temperatures may represent a plausible cause for the decline of the more sensitive colonial corals in favor of the more tolerant larger benthic foraminifera. A similar pattern is observed in most successions deposited along the margins of the Neotethys Ocean, suggesting a connection with the Late Palaeocene environmental changes that heralded the PETM hyperthermal event. Our stratigraphic analysis of the Hazara Basin strata suggests that the biotic turnovers occurred during the Palaeocene – Eocene transition started already before the onset of the Palaeocene Eocene Thermal Maximum as recorded by the geochemical proxies.

Understanding the interactions between surface and deep Earth processes is important for research in many diverse scientific areas including climate, environment, energy, georesources and biosphere. The TOPO-EUROPE initiative of the International Lithosphere Program serves as a pan-European platform for integrated surface and deep Earth sciences, synergizing observational studies of the Earth structure and fluxes on all spatial and temporal scales with modelling of Earth processes. This review provides a survey of scientific developments in our quantitative understanding of coupled surface-deep Earth processes achieved through TOPO-EUROPE. The most notable innovations include (1) a process-based understanding of the connection of upper mantle dynamics and absolute plate motion frames; (2) integrated models for sediment source-to-sink dynamics, demonstrating the importance of mass transfer from mountains to basins and from basin to basin; (3) demonstration of the key role of polyphase evolution of sedimentary basins, the impact of pre-rift and pre-orogenic structures, and the evolution of subsequent lithosphere and landscape dynamics; (4) improved conceptual understanding of the temporal evolution from back-arc extension to tectonic inversion and onset of subduction; (5) models to explain the integrated strength of Europe's lithosphere; (6) concepts governing the interplay between thermal upper mantle processes and stress-induced intraplate deformation; (7) constraints on the record of vertical motions from high-resolution data sets obtained from geo-thermochronology for Europe's topographic evolution; (8) recognition and quantifications of the forcing by erosional and/or glacial-interglacial surface mass transfer on the regional magmatism, with major implications for our understanding of the carbon cycle on geological timescales and the emerging field of biogeodynamics; and (9) the transfer of insights obtained on the coupling of deep Earth and surface processes to

In this study, we present evidence of a Paleocene–Eocene Thermal Maximum (PETM) record within a 543-m-thick (1780 ft) deep-marine section in the Gulf of Mexico (GoM) using organic carbon stable isotopes and biostratigraphic constraints. We suggest that climate and tectonic perturbations in the upstream North American catchments can induce a substantial response in the downstream sectors of the Gulf Coastal Plain and ultimately in the GoM. This relationship is illustrated in the deep-water basin by (1) a high accommodation and deposition of a shale interval when coarse-grained terrigenous material was trapped upstream at the onset of the PETM, and (2) a considerable increase in sediment supply during the PETM, which is archived as a particularly thick sedimentary section in the deep-sea fans of the GoM basin. Despite other thick PETM sections being observed elsewhere in the world, the one described in this study links with a continentalscale paleo-drainage, which makes it of particular interest for paleoclimate and source-to-sink reconstructions.

In convergent systems, the interplay between tectonics, erosion, and sedimentation controls the orogenic evolution. The nature of the interactions between these factors is still elusive due to the complex feedbacks that operate across different temporal and spatial scales. Here, we investigate these feedbacks with analog models of landscape evolution designed to account for both tectonic forcing and surface processes, using a water-saturated granular material that allows to simulate contemporary brittle deformation and surface processes. The deformation is imposed by the movement of a rigid backstop, and surface processes are triggered by simulated rainfall and runoff. We vary the convergence velocity, rainfall rate, and basal angle of the box, testing how different boundary conditions affect the balance between tectonics and surface processes. We measure the competition between input fluxes (tectonics) and output fluxes (erosion) of material, showing how sedimentation strongly affects the balance between these fluxes. The results suggest that the experimental equilibrium between tectonics and erosion can be achieved, in the analog models, only for low convergence rates (about 10 mm hr−1) and/or for high basal angle (>2°, limited sedimentation). If the foreland is overfilled with sediments and/or if convergence velocity is higher, channels decrease their erosional efficiency, moving the dynamic equilibrium between tectonics and erosion toward the former.

Nature is never at a steady state. Natural history is generated by ever-new and ever-interacting forces that produce continuous changes. At virtually all timescales, the geological record shows that these changes do not cancel each other out and, thus, that the steady state is utopic. However, we need a state of equilibrium as a starting point for modelling Nature, and the steady-state condition is widely used as a reference in idealisations aimed at understanding natural processes. The present contribution is meant as an epistemological note of caution - from Earth scientists to Earth scientists - aimed at discouraging the use of theoretical models as true evidence instead of terms of comparison.

Countless continuously interacting processes determine the functioning and evolution of the Earth. Even geodynamic and climate changes, which have been classically studied independently because they pertain to different Earth “spheres”, are linked by mutual cause–effect relationships that recent research has just started to recognize and quantify. Modeling, be it analog or numerical, is a trump card in this research for it allows rigorous integrations and interpretations of multiple observations that report on processes with different characteristic spatial and temporal scales and occurring at the Earth's surface or deep within its interior. In this chapter, I illustrate some of the main challenges of the study of the feedbacks between internal and external Earth dynamics and its relevance for the Earth Sciences as well as for facing and mitigating ongoing extreme global natural changes.

Glacial and paraglacial processes have a major influence on rock slope stability in alpine environments. Slope deglaciation causes debuttressing, stress and hydro-mechanical perturbations that promote progressive slope failure and the development of slow rock slope deformation possibly evolving until catastrophic failure. Paraglacial rock slope failures can develop soon after or thousands of years after deglaciation, and can creep slowly accelerating until catastrophic failure or nucleate sudden rockslides. The roles of topography, rock properties and deglaciation processes in promoting the different styles of paraglacial rock slope failure are still elusive. Nevertheless, their comprehensive understanding is crucial to manage future geohazards in modern paraglacial settings affected by ongoing climate change. We simulate the different modes and timing of paraglacial slope failures in an integrated numerical modelling approach that couples realistic deglaciation histories derived by modelling of ice dynamics to 2D time-dependent simulations of progressive failure processes. We performed a parametric study to assess the effects of initial ice thickness, deglaciation rate, rock-slope strength and valley shape on the mechanisms and timing of slope response to deglaciation. Our results allow constraining the range of conditions in which rapid failures or delayed slow deformations occur, which we compare to natural Alpine case studies. The melting of thicker glaciers is linked to shallower rockslides daylighting at higher elevation, with a shorter response time. More pronounced glacial morphologies influences slope lifecycle and favour the development of shallower, suspended rockslides. Weaker slopes and faster deglaciations produce to faster slope responses. In a risk-reduction perspective, we expect rockslide differentiation in valleys showing a strong glacial imprint, buried below thick ice sheets during glaciation.

The Western Domain of the Magallanes Fold-and-Thrust Belt (MFTB) between 52°-54°S is part of a poorly studied hinterland region of the southernmost Andean Cordillera. This domain consists of NNW-SSE trending tectonic slices of pre-Jurassic basement units and Upper Jurassic-Lower Cretaceous ophiolitic complexes and volcano-sedimentary successions of the Rocas Verdes Basin (RVB). New detrital zircon U–Pb ages of metatuffs and metapsammopelites constrain episodes of Late Jurassic rift-related volcanism (ca. 160 Ma) followed by Early Cretaceous sedimentation (ca. 125 Ma) during the opening of the RVB. Shear bands developed in the RVB units further record the initial phases of the Andean Orogeny. The 30-km wide thrust stack located on top of the Eastern Tobífera Thrust consists of mylonitic metatuffs, metapelites and metabasalts with a NE-verging brittle-ductile S1* foliation. Phengite-bearing metatuffs commonly record pressure-temperature (P-T) conditions between ~3–6 kbar and ~210–460 °C, consistent with underthrusting of the RVB beneath the parautochthonous magmatic arc in the west. Peak metamorphic conditions of ~6 kbar and 460 °C are derived from a metapsammopelite with textures of contact metamorphism overprinting early mylonitic structures (at least S1*). A back-arc quartz-diorite, intruded at ca. 83 Na, is in contact with the metapsammopelite and constrain the minimum age of deformation at deep crustal depths. Campanian-Maastrichtian (ca. 70–73 Ma) 40Ar/39Ar phengite dates from a mylonitic metapelite indicate the timing of thrusting and backthrusting during the initial uplift of the underthrusted crustal stack. These findings reveal a ~400 km along-strike connection of mylonite belts in a continent-verging thrust structure that became active at the onset of the Andean orogeny during the closure of the Rocas Verdes back-arc marginal basin.

Asthenosphere-lithosphere interactions modulated by surface processes generate outstanding topographies and sedimentary basins, but the nature of these interactions and the mechanisms through which they control the evolution of extensional tectonic settings are elusive. Basal lithospheric shearing due to plume-related mantle flow leads to extensional lithospheric rupturing and associated magmatism, rock exhumation, and topographic uplift away from the plume axis by a distance inversely correlated to the lithospheric elastic thickness. When moisturized air encounters a topographic barrier, it rises, decompresses, and saturates, leading to enhanced erosion on the windward side of the uplifted terrain. Orographic precipitation and asymmetric erosional unloading facilitate strain localization and lithospheric rupturing on the wetter and more eroded side of an extensional system. This simple analytical model is validated against thermo-mechanical numerical experiments where a rheologically stratified lithosphere above an asthenospheric plume is subject to fluvial erosion proportional to stream power during extension. Our modeling results are consistent with Paleogene mantle upwelling and flood basalts in Ethiopia synchronous to distal initiation of lithospheric stretching/rupturing in the Gulf of Aden, which progressively propagates into the Red Sea. The present-day asymmetric topography and extensional structures in the Main Ethiopian Rift may also be an effect of a Neogene-to-present orographic erosional gradient. Although inherently related to the lithosphere rheology, the evolution of continental rifts appears even more conditioned by the mantle and surface dynamics than previously thought.

Decades of scientific research on the European Alps have helped quantify the vast array of processes that shape the Earth's surface. Patterns in rock exhumation, surface erosion and topographic changes can be compared to sediment yields preserved in sedimentary basins or collected from modern rivers. Erosion-driven isostatic uplift explains up to ~50% of the modern geodetic rock uplift rates; the remaining uplift reveals the importance of internal processes (tectonics, deep-seated geodynamics) and external processes (glacial rebound, topographic changes). We highlight recent methodological and conceptual developments that have contributed to our present view of the European Alps, and we provide suggestions on how to fill the gaps in our understanding.

Surface processes and magmatism condition the structural evolution of continental rifts and passive margins through mechanical and thermal effects on the lithosphere rheology. However, their inter-relationships in extensional settings are largely unknown. Here, I use coupled thermo-mechanical geodynamic and landscape evolution numerical modeling to assess the links between erosion of rift shoulders, sedimentation within the rift basin and extensional rock melting. Results suggest that, when the crust is thinner than ~40 km, the extension rate is slower than ~2 cm/yr and the mantle potential temperature is below ~1230 °C, efficient surface processes may double crustal melting by Moho lowering and inhibit mantle decompression melting by ~50% through sediment loading within the rift basin. It is thus likely that surface processes significantly influenced the magmatic activity of a number of extensional settings worldwide – e.g. the Mediterranean, the Gulf of California, the Iberia-Newfoundland margin, and the South China Sea. Because magmatism and surface processes affect jointly the geological carbon cycle, the surface processes forcing on extensional rock melting investigated here involves an additional means of linkage between plate tectonics and climate changes.

Orogens and volcanic arcs at continental plate margins are primary surface expressions of convergent plate tectonics. Although it is established that climate affects the shape, size, and architecture of orogens via orographic erosion gradients, the ascent of magma through the crust and location of volcanoes along magmatic arcs have been considered insensitive to erosion. However, available data reveal westward migration of late-Cenozoic volcanic activity in the Southern Andes and Cascade Range where orography drives an eastward migration of the topographic water divide by increased precipitation and erosion along west-facing slopes. Thermomechanical numerical modeling shows that orographic erosion and the associated leeward topographic migration may entail asymmetric crustal structures that drive the magma ascent toward the region of enhanced erosion. Despite the different tectonic histories of the Southern Andes and the Cascade Range, orographic erosion is a shared causal mechanism that can explain the late-Cenozoic westward migration of the volcanic front along both magmatic arcs.

Late Miocene calc-alkaline intrusions in the back-arc of Southern Patagonia mark an eastward migration of the arc due to accelerated subduction velocity of the Nazca plate or slab flattening preceding active ridge subduction. Amongst these intrusions are the emblematic Torres del Paine (51°S) and Fitz Roy (49°S) plutonic complexes, crystalised at ca. 12.5 and ca. 16.5 Ma, respectively (Leuthold et al., 2012; Ramírez de Arellano et al., 2012). Both intrusions are located at the eastern boundary of the Southern Patagonian Icefield and form prominent peaks with steep slopes that are ~3 km higher in elevation than the surrounding low-relief foreland. Their exhumation has been proposed as a response to glacial erosion and associated glacial rebound since ca. 7 Ma (Fosdick et al., 2013), and/or by regional dynamic uplift between 14 and 6 Ma due to the northward migration of subducting spreading ridges (Guillaume et al., 2009). Here we present a new data set of apatite and zircon (U-Th)/He from both plutonic complexes, numerically modelled to unravel their late-Neogene to Quaternary thermal histories. Our results show three rapid cooling periods for the Fitz Roy intrusion: at ca. 9.5 Ma, at ca. 7.5 Ma, and since ca. 1 Ma. For Torres del Paine, inverse thermal modelling reveals short and rapid cooling at ca. 6.5 Ma followed by late-Quaternary final cooling. The 10 Ma cooling signal only evidenced in the northern plutonic complex (Fitz Roy) may represent an exhumation response to the northward migrating subduction of spreading ridge segments, causing localized dynamic uplift. Thus, the absence of exhumation signal before 6.5 Ma in the southern part (Torres del Paine) suggest that the spreading ridge subduction must have occurred before its 12.5 Ma emplacement. On the other hand, rapid cooling by similar magnitude in both plutonic complexes between ca. 7.5–6.5 Ma, likely reflects the onset of late-Cenozoic glaciations in Southern Patagonia. Finally, the late-stage Quaternary

Feedbacks between climatic and geological processes are highly controversial and testing them is a key challenge in Earth sciences. The Great Escarpment of the Arabian Red Sea margin has several features that make it a useful natural laboratory for studying the effect of surface processes on deep Earth. These include strong orographic rainfall, convex channel profiles versus concave swath profiles on the west side of the divide, morphological disequilibrium in fluvial channels, and systematic morphological changes from north to south that relate to depth changes of the central Red Sea. Here we show that these features are well interpreted with a cycle that initiated with the onset of spreading in the Red Sea and involves feedbacks between orographic precipitation, tectonic deformation, mid-ocean spreading and coastal magmatism. It appears that the feedback is enhanced by the moist easterly trade winds that initiated largely contemporaneously with sea floor spreading in the Red Sea.

Volcanic arcs at convergent plate margins are primary surface expressions of plate tectonics. Although climate affects many of the manifestations of plate tectonics via erosion, the upwelling of magmas and location of volcanic arcs are considered insensitive to climate. In the Southern Andes, subduction of the Nazca oceanic plate below the South American continent generates the Southern Andes Volcanic zone. Orographic interactions with Pacific westerlies lead to high precipitation and erosion on the western slopes of the belt between 42-46°S. At these latitudes, the topographic water divide and the volcanic arc are respectively farther and closer to the subduction trench than at lower latitudes, despite a constant subduction dip angle along strike. Here, we use thermomechanical numerical modeling to investigate how magma upwelling is affected by topographic changes due to orography. We show that a leeward topographic shift may entail a windward asymmetry of crustal structures accommodating the magma upwelling, consistent with the observed trench-ward migration of the Southern Andes Volcanic Zone. A climatic control on the location of volcanic arcs via orography and erosion is thus revealed.

The Southern Andes Volcanic zone (SVZ) is located between latitudes 33-46°S in the western margin of the South American continental plate, above the subducting Nazca oceanic plate. Although the slab dip angle is constant (~25°) along strike, the distance between the volcanic arc and the subduction trench decreases southward. In the northern segment (33-41°S) the volcanoes are co-located with the main orogenic water divide, whereas in the southern segment (41-46°S) the water divide is shifted eastward and the volcanic arc is shifted westward. The eastward water divide migration in the southern segment is explained by an orographic effect due to the westerlies winds, which causes high precipitation (>2 m/yr) and erosion rates (>1.5 mm/yr) on the upwind side of the orogen. Thermomechanical visco-elasto-plastic numerical models exploring the effects of the topographic shift on the magma upwelling path explain the westward migration of the volcanic arc. Results show that when the topographic barrier is shifted to the east with respect to a central magmatic source, asymmetric strain due to the magma emplacement into the crust drives preferential westward magma upwelling. The southern segment of the SVZ is proximal to an important strike slip fault system, the Liquiñe-Ofqui fault zone. We propose that the (re-)activation of these fracture zone on the western side of the Southern Andes is related to the orographic migration of the water divide during magma upwelling. This conclusion is further supported by the lack of structures accommodating magma emplacement/eruption and volcanoes east of the water divide. If correct, this is the first-recognized example of a climatic control on the location of a volcanic arc in convergent settings.

Established theories ascribe much of the observed long‐term Cenozoic climate cooling to atmospheric carbon consumption by erosion and weathering of tectonically uplifted terrains, but climatic effects due to changes in magmatism and carbon degassing are also involved. At timescales comparable to those of Milankovitch cycles, late Cenozoic building/melting of continental ice sheets, erosion, and sea level changes can affect magmatism, which provides an opportunity to explore possible feedbacks between climate and volcanic changes. Existing data show that extinction of Neo‐Tethyan volcanic arcs is largely synchronous with phases of atmospheric carbon reduction, suggesting waning degassing as a possible contribution to climate cooling throughout the early to middle Cenozoic. In addition, the increase in atmospheric CO2 concentrations during the last deglaciation may be ascribed to enhanced volcanism and carbon emissions due to unloading of active magmatic provinces on continents. The deglacial rise in atmospheric CO2 points to a mutual feedback between climate and volcanism mediated by the redistribution of surface masses and carbon emissions. This may explain the progression to higher amplitude and increasingly asymmetric cycles of late Cenozoic climate oscillations. Unifying theories relating tectonic, erosional, climatic, and magmatic changes across timescales via the carbon cycle offer an opportunity for future research into the coupling between surface and deep Earth processes.

Recent measurements of surface vertical displacements of the European Alps show a correlation between vertical velocities and topographic features, with widespread uplift at rates of up to ~2–2.5 mm/a in the North-Western and Central Alps, and ~1 mm/a across a continuous region from the Eastern to the South-Western Alps. Such a rock uplift rate pattern is at odds with the horizontal velocity field, characterized by shortening and crustal thickening in the Eastern Alps and very limited deformation in the Central and Western Alps. Proposed mechanisms of rock uplift rate include isostatic response to the last deglaciation, long-term erosion, detachment of the Western Alpine slab, as well as lithospheric and surface deflection due to mantle convection. Here, we assess previous work and present new estimates of the contributions from these mechanisms. Given the large range of model estimates, the isostatic adjustment to deglaciation and erosion are sufficient to explain the full observed rate of uplift in the Eastern Alps, which, if correct, would preclude a contribution from horizontal shortening and crustal thickening. Alternatively, uplift is a partitioned response to a range of mechanisms. In the Central and Western Alps, the lithospheric adjustment to deglaciation and erosion likely accounts for roughly half of the rock uplift rate, which points to a noticeable contribution by mantle-related processes such as detachment of the European slab and/or asthenospheric upwelling. While it is difficult to independently constrain the patterns and magnitude of mantle contributions to ongoing Alpine vertical displacements at present, future data should provide additional insights. Regardless, interacting tectonic and surface mass redistribution processes, rather than an individual forcing, best explain ongoing Alpine elevation changes

Slab rollback results in the development of low-angle normal faults (detachments) and metamorphic core complexes (MCCs) in back-arc domains. Although the mechanical consequences of slab dynamics on lithospheric and crustal behaviors have already been studied, thermal effects have not been investigated yet. This study shows that slab rollback produces lithospheric-scale thermal perturbations intrinsically associated with emplacement of amagmatic high-enthalpy geothermal systems. Using a multi-scale numerical modeling approach, with lithospheric-scale 3-D thermo-mechanical models of subduction, and 2-D models of fluid flow at the scale of detachments, we demonstrate that subduction-induced extensional tectonics controls the genesis and distribution of crustal-scale thermal domes from the base of the crust, and the location of high-energy geothermal systems. We find that when slab tearing occurs, Moho temperatures can temporarily increase by up to 250 °C due to significant shear heating in the flowing upper mantle. Associated thermal anomalies (with characteristic width and spacing of tens and hundreds of km, for crustal and lithospheric scales, respectively) then migrate systematically toward the retreating trench. These thermal domes weaken the crust, localize deformation and enhance the development of crustal-scale detachments. These thermo-mechanical instabilities mimic genesis of high-temperature MCCs with migmatitic cores in the back-arc domain, such as those of the Menderes (western Anatolia, Turkey) and Larderello (southern Tuscany) provinces in the Mediterranean realm, and those in the Basin and Range (western United States), where detachments control the bulk of the heat transport. At the scale of MCCs, the bulk fluid flow pattern is controlled by topography-driven flow while buoyancy-driven flow dominates within the permeable detachments, focusing reservoir location of high-energy geothermal systems at shallow depth beneath the detachments.

We present here a number of geological observations in extensional contexts, either continental rifts or back-arcs, that show different situations of potential coupling between asthenospheric flow and crustal deformation. Several of these examples show a deformation distributed over hectometre to kilometre thick shear zones, accommodated by shallow dipping shear zones with a constant asymmetry over large distances. This is the case of the Mediterranean back-arc basins, such as the Aegean Sea, the northern Tyrrhenian Sea, the Alboran domain or the Gulf of Lion passive margin. Similar types of observation can be made on some of the South Atlantic volcanic passive margins and the Afar region, which were formed above a mantle plume. In all these examples the lithosphere is hot and the lithospheric mantle thin or possibly absent. We discuss these contexts and the main controlling parameters for this asymmetrical distributed deformation that implies a simple shear component at the scale of the lithosphere. These parameters include an original heterogeneity of the crust and lithosphere (tectonic heritage), lateral density gradients and contribution of the underlying asthenospheric flow through basal drag or basal push. We discuss the relations between the observed asymmetry and the direction and sense of the mantle flow underneath. The chosen examples suggest that two main mechanisms can explain the observed asymmetry: (1) shearing parallel to the Moho in the necking zone during rifting and (2) viscous coupling of asthenospheric flow and crustal deformation in back-arc basins and above plumes. Slipping along pre-existing heterogeneities seems a second-order phenomenon at lithospheric or crustal scale.

The Messinian Salinity Crisis (MSC) involved the progressive isolation of the Mediterranean Sea from the Atlantic between 5.97 and 5.33 Ma, and a sea-level fall whose timing, modalities, and magnitude remain actively debated. At that time, the central Mediterranean was undergoing strong tectonic activity due to the rollback of the Adria slab and eastward migration of the Apenninic belt. The combined effects of the post-evaporitic MSC sea-level drop and morphostructural changes (due to the Intra-Messinian phase) resulted in a regional unconformity, which shows erosive markers and conformable relationships with the Messinian and Mio–Pliocene boundary in the Po Plain and Northern Adriatic Foreland. Here, we produce a palaeotopographic reconstruction of the Po Plain-Northern Adriatic region (PPNA) during the Messinian peak desiccation event based on such regional unconformity. We mapped this surface through wells and 2D seismic data form Eni's private dataset. The unconformity shows V-shaped incisions matching the present-day southern Alpine valleys and filled with Messinian post-evaporitic and Pliocene deposits, suggesting that the modern drainage network is at least of late Messinian age. The Messinian unconformity has been restored to its original state through flexural-backstripping numerical modelling. The resulting landscape suggests a maximum sea-level drop of 800–900 m during the MSC peak, and is consistent with stratigraphic and sedimentologic data provided by previous works. The modelled shoreline separates the subaerially eroded land from an elongated basin composed by two ca. 400 and 1,000 m deep depocentres during the maximum sea-level drop. These results suggest that the Mediterranean was split in at least three sub-basins subject to independent base levels, fresh-water budgets, and flexural responses during the maximum lowstand.

The formation of mountain belts or rift zones is commonly attributed to interactions between plates along their boundaries, but the widely distributed deformation of Asia from Himalaya to the Japan Sea and other back-arc basins is difficult to reconcile with this notion. Through comparison of the tectonic and kinematic records of the last 50 Ma with seismic tomography and anisotropy models, we show that the closure of the former Tethys Ocean and the extensional deformation of East Asia can be best explained if the asthenospheric mantle transporting India northward, forming the Himalaya and the Tibetan Plateau, reaches East Asia where it overrides the westward flowing Pacific mantle and contributes to subduction dynamics, distributing extensional deformation over a 3,000-km wide region. This deep asthenospheric flow partly controls the compressional stresses transmitted through the continent-continent collision, driving crustal thickening below the Himalayas and Tibet and the propagation of strike-slip faults across Asian lithosphere further north and east, as well as with the lithospheric and crustal flow powered by slab retreat east of the collision zone below East and SE Asia. The main shortening direction in the deforming continent between the collision zone and the Pacific subduction zones may in this case be a proxy for the direction of flow in the asthenosphere underneath, which may become a useful tool for studying mantle flow in the distant past. Our model of the India-Asia collision emphasizes the role of asthenospheric flow underneath continents and may offer alternative ways of understanding tectonic processes.

The Messinian Salinity Crisis (MSC) involved the progressive isolation of the Mediterranean Sea from the Atlantic between 5.97 and 5.33 Ma, and a sea-level fall whose timing, modalities, and magnitude remain actively debated. At that time, the central Mediterranean was undergoing strong tectonic activity due to the rollback of the Adria slab and eastward migration of the Apenninic belt. The combined effects of the post-evaporitic MSC sea-level drop and morphostructural changes (due to the Intra-Messinian phase) resulted in a regional unconformity, which shows erosive markers and conformable relationships with the Messinian and Mio–Pliocene boundary in the Po Plain and Northern Adriatic Foreland. Here, we produce a palaeotopographic reconstruction of the Po Plain-Northern Adriatic region (PPNA) during the Messinian peak desiccation event based on such regional unconformity. We mapped this surface through wells and 2D seismic data form Eni's private dataset. The unconformity shows V-shaped incisions matching the present-day southern Alpine valleys and filled with Messinian post-evaporitic and Pliocene deposits, suggesting that the modern drainage network is at least of late Messinian age. The Messinian unconformity has been restored to its original state through flexural-backstripping numerical modelling. The resulting landscape suggests a maximum sea-level drop of 800–900 m during the MSC peak, and is consistent with stratigraphic and sedimentologic data provided by previous works. The modelled shoreline separates the subaerially eroded land from an elongated basin composed by two ca. 400 and 1,000 m deep depocentres during the maximum sea-level drop. These results suggest that the Mediterranean was split in at least three sub-basins subject to independent base levels, fresh-water budgets, and flexural responses during the maximum lowstand. © 2018 The Authors. Basin Research © 2018 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and Internati

We constrain and model the geometry of the Zagros foreland to assess the equivalent elastic thickness of the northern edge of the Arabian plate and the loads that have originated due to the Arabia-Eurasia collision. The Oligo-Miocene Asmari formation, and its equivalents in Iraq and Syria, is used to estimate the post-collisional subsidence as they separate passive margin sediments from the younger foreland deposits. The depth to these formations is obtained by synthesizing a large database of well logs, seismic profiles and structural sections from the Mesopotamian basin and the Persian Gulf. The foreland depth varies along strike of the Zagros wedge between 1 and 6 km. The foreland is deepest beneath the Dezful embayment, in southwest Iran, and becomes shallower towards both ends. We investigate how the geometry of the foreland relates to the range topography loading based on simple flexural models. Deflection of the Arabian plate is modelled using point load distribution and convolution technique. The results show that the foreland depth is well predicted with a flexural model which assumes loading by the basin sedimentary fill, and thickened crust of the Zagros. The model also predicts a Moho depth consistent with Free-Air anomalies over the foreland and Zagros wedge. The equivalent elastic thickness of the flexed Arabian lithosphere is estimated to be ca. 50 km. We conclude that other sources of loading of the lithosphere, either related to the density variations (e.g. due to a possible lithospheric root) or dynamic origin (e.g. due to sublithospheric mantle flow or lithospheric buckling) have a negligible influence on the foreland geometry, Moho depth and topography of the Zagros. We calculate the shortening across the Zagros assuming conservation of crustal mass during deformation, trapping of all the sediments eroded from the range in the foreland, and an initial crustal thickness of 38 km. This calculation implies a minimum of 126 ± 18 km of crustal shorten

Between 5 and 6 million years ago, during the so-called Messinian salinity crisis, the Mediterranean basin became a giant salt repository. The possibility of abrupt and kilometre-scale sea-level changes during this extreme event is debated. Messinian evaporites could signify either deep- or shallow-marine deposits, and ubiquitous erosional surfaces could indicate either subaerial or submarine features. Significant and fast reductions in sea level unload the lithosphere, which can increase the production and eruption of magma. Here we calculate variations in surface load associated with the Messinian salinity crisis and compile the available time constraints for pan-Mediterranean magmatism. We show that scenarios involving a kilometre-scale drawdown of sea level imply a phase of net overall lithospheric unloading at a time that appears synchronous with a magmatic pulse from the pan-Mediterranean igneous provinces. We verify the viability of a mechanistic link between unloading and magmatism using numerical modelling of decompression partial mantle melting and dyke formation in response to surface load variations. We conclude that the Mediterranean magmatic record provides an independent validation of the controversial kilometre-scale evaporative drawdown and sheds new light on the sensitivity of magmatic systems to the surface forcing.

Between 5 and 6 million years ago, during the so-called Messinian salinity crisis, the Mediterranean basin became a giant salt repository. The possibility of abrupt and kilometre-scale sea-level changes during this extreme event is debated. Messinian evaporites could signify either deep-or shallow-marine deposits, and ubiquitous erosional surfaces could indicate either subaerial or submarine features. Significant and fast reductions in sea level unload the lithosphere, which can increase the production and eruption of magma. Here we calculate variations in surface load associated with the Messinian salinity crisis and compile the available time constraints for pan-Mediterranean magmatism. We show that scenarios involving a kilometre-scale drawdown of sea level imply a phase of net overall lithospheric unloading at a time that appears synchronous with a magmatic pulse from the pan-Mediterranean igneous provinces. We verify the viability of a mechanistic link between unloading and magmatism using numerical modelling of decompression partial mantle melting and dyke formation in response to surface load variations. We conclude that the Mediterranean magmatic record provides an independent validation of the controversial kilometre-scale evaporative drawdown and sheds new light on the sensitivity of magmatic systems to the surface forcing.