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The Colorado basin in the SW Atlantic is one of the key exploratory frontier basins along the Argentine shelf. The stratigraphy shows a typical rift basin, divided into two major seismic successions, a Jurassic-Lower Cretaceous synrift followed by an Upper Cretaceous to Cenozoic postrift. They represent, respectively, the breakup of Gondwana and passive margin evolution. While the synrift basin formation was associated with the development of structural grabens, the preservation of thick (thousands of meters) postrift sequences are still debated because they cannot be accounted for only by thermal subsidence. In this work, we conducted a multimethodological subsidence analysis across the Colorado basin, including part of the continental slope. We performed a 1D backstripping analysis on 10 hydrocarbon exploration wells and 32 pseudo-wells, covering the whole basin area and a uniform stretching model, which were supported using dynamic topography data from the study region. From the backstripping analyses, considering the six major postrift sedimentary successions described in the literature, we could recognize three subsidence stages. An initial rapid subsidence stage during the post-rift (125–83 Ma), which is restricted to the main depocenters, followed by a stage of generalized and low subsidence focused on the main axis of the basin (83–33 Ma), with an increase in the last 33 my (33–0 Ma). The stretching models exhibit a typical asymptotic curve, depicting significant subsidence at the onset of the postrift stage, gradually diminishing to minimal values within a few tens of millions of years. Upon comparing the backstripping curves with the stretching subsidence models, particularly during the final flat segments, a residual negative value emerges over time (locally exceeding −500 m), indicating considerable residual subsidence during the Cenozoic postrift evolution along the Colorado Basin. This could be interpreted as dynamic subsidence. This residual sinking in the Argentina shelf matches with dynamic topography numerical models in the study region as well as the occurrence of accumulated slabs in the mantle detected by seismic tomography studies. We propose that the accumulation of slabs along this segment of the South American subduction zone might be the drivers of dynamic subsidence, which assisted to the preservation of a large thickness of post-rift strata along the SW Atlantic margin. • Colorado Basin's post-rifting phase revealed three distinct subsidence stages. • Cenozoic residual subsidence linked to dynamic topography detected. • Dynamic topography unveils mantle slab accumulation from South American subduction. • Atlantic post-rift subsidence differs notably from Africa, influenced by dynamic topography from subducted slabs. [ABSTRACT FROM AUTHOR]

Global sea level change can be inferred from sequence stratigraphic and continental flooding data. These methods reconstruct sea level from peri-cratonic and cratonic basins that are assumed to be tectonically stable and sometimes called reference districts, and from spatio-temporal correlations across basins. However, it has been understood that long-wavelength (typically hundreds of km) and low-amplitude (<2 km) vertical displacements of the Earth's surface due to mantle flow, namely dynamic topography, can occur in the absence of crustal deformation. Dynamic topography can drive marine inundation or regional emergence of continents and must be taken into consideration for eustasy estimates. Our analysis indicates that the long-term trend in global-scale maximum flooding over the late Paleozoic generally correlates with global sea level curves. The first-order flooding history of North America correlates with some estimates of eustasy. The Paleozoic inundation of South America does not follow long-term sea level variations. The flooding lows during the Early Carboniferous and high during the Late Carboniferous are at odds with estimates of eustasy and can be explained by dynamic uplift and subsidence, respectively. Our dynamic topography models indicate that the Yangtze Platform of South China experienced significant dynamic subsidence during the transition from Permian to Triassic largely due to proto-Pacific subduction and its northward motion to collide with North China. The reference districts – Western New York, Oklahoma and Kansas, and West Texas in North America – were to some degree affected by dynamic uplift and subsidence associated with long-lived Panthalassa subduction zones, closure of the Rheic Ocean and large-scale upwelling above the African deep-mantle structure during late Paleozoic times. This indicates that some published global sea level curves may include non-eustatic signals such as dynamic uplift or subsidence. The interpretation of stratigraphic data gathered from these reference districts should be treated with caution to estimate global sea level variations. Unlabelled Image • First-order inundation of North America in the late Paleozoic correlates with eustasy. • Some patterns in flooding of South America can be explained by dynamic topography. • The South China reference district for global sea level was affected by mantle flow. • Dynamic topography should be considered to understand Paleozoic sea level change. [ABSTRACT FROM AUTHOR]

Two large, seismically slow regions in the lower mantle beneath Africa and the Pacific Ocean are sometimes referred to as "superplumes". This name evokes images of large-scale active upwellings. However, it remains unclear whether these features are real or represent collections of multiple regular mantle plumes. Here, we investigate the implications of these upwellings for dynamic topography. We combine detailed measurements of oceanic residual topography from Hoggard et al. (2016) with continental constraints derived from CRUST1.0 to produce a global model expanded in spherical harmonics. Observed dynamic topography is subsequently compared to predictions derived from mantle flow following Steinberger (2016) using tomographic density models. Results yield relatively good overall agreement and amplitude spectra with similar slopes, except for degree two (i.e. > 10,000 km wavelengths) where predicted amplitude is more than two times as large and is dominated by contributions from the lower mantle. Predictive models suggest two large-scale uplifted regions above the "superplumes" that are barely seen in the observed topography. We suggest that this mismatch can only partly be reconciled by altering the seismic velocity to density conversion factor or by including the effects of lower mantle chemical heterogeneity. In addition, it may be important to consider more significant revisions to the lower mantle flow patterns, such as those possibly induced by different radial viscosity profiles and laterally-varying or anisotropic lower mantle viscosity. • Lower mantle dominates degree-two dynamic topography. • Upper mantle dominates all other degrees. • Predicted dynamic topography amplitude at degree two exceeds observations by more than a factor 2. [ABSTRACT FROM AUTHOR]

The Broadly Rifted Zone (BRZ) is a ~ 315 km wide zone of extension in southern Ethiopia. It is located between the Southern Main Ethiopian Rift and the Eastern Branch of the East African Rift System (EARS) represented by the Kenya-Turkana Rift. The BRZ is characterized by NE-trending ridges and valleys superimposed on regionally uplifted (~ 2 km average elevation) terrain. Previous studies proposed that the BRZ is an overlap zone resulted from northward propagation of the Kenya-Turkana Rift and southward propagation of the Southern Main Ethiopian Rift. To understand the relationship between the BRZ's extensional style and its crustal and upper mantle structures, this work first estimated the Moho depth using the two-dimensional (2D) radially-averaged power spectral analysis of the World Gravity Map. Verification of these results was accomplished through lithospheric-scale 2D forward gravity models along E-W profiles. This work found that the Moho topography beneath the BRZ depicts a dome-like shape with a minimum depth of ~ 27 km in the center of the dome. This work proposes that the Moho doming, crustal arching underlying the BRZ and associated topographic uplift are the result of asthenospheric mantle upwelling beneath the BRZ. This upwelling changed to a NE-directed lateral mantle flow at shallower depth. This is supported by seismic tomography imaging which shows slow S-wave velocity anomaly at lithospheric depth of 75 km to 150 km stretching in a NE-SW direction from beneath the BRZ to the Afar Depression. This work proposes that the asthenospheric upwelling created gravitationally unstable dynamic topography that triggered extensional gravitational collapse leading to the formation of the BRZ as a wide rift within the narrow rift segments of the EARS. [ABSTRACT FROM AUTHOR]

A fundamental scientific question is, what controls the Earth's topography? Although the theoretical principles of isostasy, flexure, and dynamic topography are widely discussed, the parameters needed to apply these principles are frequently not available. Isostatic factors controlling lithospheric buoyancy are frequently uncertain and non-isostatic factors, such as lithospheric bending towards subduction zones and dynamic topography, are hard to distinguish. The question discussed here is whether a set of simple rules that relate topography to lithospheric structure in various tectonic environments can be deduced in a way that missing parameters can be approximated; or does each area behave differently, making generalizations problematic. We contribute to this issue analyzing the Asia–Africa–Arabia–Europe domain following a top-down strategy. We compile a new crustal thickness map and remove the contribution of the crust from the observed elevation. Then, the challenge is to interpret the residual topography in terms of mantle lithosphere buoyancy and dynamics. Based on systematic relationships between tectonic environments and factors controlling topography, we argue that crustal buoyancy and mantle lithospheric density can be approximated from available geological data and that regions near mantle upwelling or downwelling are easily identified by their extreme residual topography. Yet, even for other areas, calculating lithospheric thickness from residual topography is problematic, because distinguishing variations in mantle lithosphere thickness from sub-lithospheric dynamics is difficult. Fortunately, the area studied here provides an opportunity to examine this issue. Based on the conjunction between the Afar Plume and the mid-ocean ridge in the nearby Gulf of Aden and southern Red Sea, we constrain the maximal amplitude of dynamic topography to ~ 1 km. This estimate is based on a narrow definition of dynamic topography that only includes sub-lithospheric processes and using mid-ocean ridges as reference, where mantle lithosphere buoyancy is zero. [ABSTRACT FROM AUTHOR]

Due to the Mesozoic multi-plate convergence, prominent continental marginal tectonic belts were formed in East Asia. The significant intra-continental magmatic events in the interior of East Asia were also closely related to the subduction of the surrounding oceans. Therefore, clarifying the subduction-related mantle dynamics during the Mesozoic super-convergence in East Asia is critical in understanding the crust-mantle interactions and the episodic tectono-magmatism. In this study, we obtain the subduction-related dynamic topography by coupling global mantle flow and plate reconstruction motions to capture the evolution scenarios in 200–90 Ma. Our modeling results are as follows: (1) In the Early Jurassic, the East Asian continental margin breakup is closely related to the mantle-driven dynamic topography. The offshore dynamic subsidence dominates the continental breakup. (2) The closure of the Paleo-Tethys Ocean and the subduction of the Bangonghu-Nujiang Ocean contribute to the southward migration of the dynamic topography. Concurrently, the continuous subduction of the Paleo-Pacific Plate leads to the onshore dynamic uplift, which results in subduction-related orogenesis in eastern East Asia. The dynamic uplift does not massively progress westward in Mainland China, suggesting that extensive intra-continental compressional deformation results from tectonic uplift rather than mantle-induced dynamic uplift. (3) The regression of the dynamic subsidence zone since 130 Ma marks the start of the topographic collapse in the East Asian continental margin through the back-arc extension. (4) The alternating compression-extension scenarios are identified in the main compressional and extensional stages, respectively, showing that dynamic topography is closely related to the evolution of the marginal tectonic belts in eastern East Asia. In conclusion, the subduction-related dynamic topography systematically reveals the deep dynamics involved in the formation, evolution, and collapse of the marginal tectonic belts in East Asia and is of great significance in understanding the related mantle dynamics during the Late Mesozoic. • We obtain the Late Mesozoic subduction-related dynamic topography models in East Asia. • Subduction-related dynamic topography can reveal the episodic evolution of the marginal orogenic belts of eastern East Asia. • Tectonic uplift is the primary driver of Late Mesozoic intracontinental deformation in South China. [ABSTRACT FROM AUTHOR]

The Moulouya river system has intensely eroded the Arhbalou, Missour, and Guercif Neogene foreland basins in northeastern Morocco, having changed from net aggradation during the Miocene–early Pliocene to net incision punctuated by alluvial fan deposition at late Pliocene or early Quaternary time. This region as a whole has experienced mantle-driven, surface uplift (dynamic topography) since the late Cenozoic, being locally affected by uplift due to crustal shortening and thickening of the Middle Atlas too. Knickpoints located along the major streams of the Moulouya fluvial network, appear on both the undeformed margins of the Missour and Guercif foreland basins (High Plateaus), as well as along the thrust mountain front of the southern Middle Atlas, where they reach heights of 800–1000 m. 500–550 m of the knickpoint vertical incision might be explained by long-wavelength mantle-driven dynamic surface uplift, whereas the remaining 450–500 m in the southern Middle Atlas front and 200–300 m in the northeastern Middle Atlas front seem to be thrust-related uplift of the Jebel Bou Naceur. Be-10 terrestrial cosmogenic nuclides have been used to date two Quaternary river terraces in the Chegg Ard valley at 62 ± 14 ka and 411 ± 55 ka. The dated terraces allow the incision rates associated with the frontal structures of the Middle Atlas to be estimated at ~ 0.3 mm yr − 1 . Furthermore, these ages have served to evaluate mantle-driven regional surface uplift since the middle Pleistocene in the central Missour basin, yielding values of ~ 0.1–0.2 mm yr − 1 . [ABSTRACT FROM AUTHOR]

Abstract: The relative tectonic quiescence of the Australian continent during the Cenozoic makes it an excellent natural laboratory to study recent large-scale variations in surface topography, and processes that influence changes in its elevation. Embedded within this topography is a fluvial network that is sensitive to variations in horizontal and vertical motions. The notion that a river acts as a ‘tape recorder’ for vertical perturbations suggests that changes in spatial and temporal characteristics of surface uplift can be deduced through the analysis of longitudinal river profiles. We analyse 20 longitudinal river profiles around the Australian continent. Concave upward profiles in northeast Australia indicate an absence of recent surface uplift. In contrast, the major knickzones within longitudinal profiles of rivers in southwest Australia suggest recent surface uplift. Given the lack of recent large-scale tectonic activity in that region, this uplift requires an explanation. Applying an inverse algorithm to river profiles of south Western Australia reveals that this surface uplift started in the Eocene and culminated in the mid-late Neogene. The surface uplift rates deduced from this river profile analysis generally agree with independent geological observations including preserved shallow-marine sediment outcrops across the Eucla Basin and south Western Australia. We show that the interplay between global sea level and long-wavelength dynamic topography associated with south Western Australia's plate motion path over the remnants of an ancient Pacific slab is a plausible mechanism driving this surface uplift. [Copyright &y& Elsevier]

The origin of the high-elevation and neotectonism of western Mongolia remains enigmatic. Several studies suggested that the mechanisms might, at least in part, lurk in the mantle, but little consensus was reached on its pattern and contributions to the surface topography. Geophysical and geodynamical studies indicated that the viscous stresses exerted by mantle flow can maintain a substantial proportion of topography and gravity anomaly, resulting in a high long-wavelength free-air admittance and dynamic topography. These two estimates are commonly used as indicators to detect mantle flow. In this study, we provided evidence for mapping mantle flow beneath western Mongolia by lithospheric flexure analysis in terms of the relationship between gravity anomaly and topography. Our results show a significant dynamic topography of an amplitude over 500 m and a high long-wavelength free-air admittance of value over 35 mGal/km in the southwestern part of western Mongolia, leading to a reliable argument for mantle upwelling beneath western Gobi Altai. We also reveal that the long-wavelength free-air admittance deviates from lithospheric flexure isostasy in the Hangai Dome. Combined with other studies, we infer that horizontal flow fed by the upwelling from western Gobi Altai supports the Hangai Dome uplift. Our results demonstrate the significant role of mantle flow in shaping the present-day anomalous topography and tectonism in western Mongolia, central Asia. • Mantle flow beneath western Mongolia was imaged by lithospheric flexure analysis. • Mantle upwelling from western Gobi-Altai feeds a horizontal flow to the Hangai Dome. • Mantle flow contributes to the anomalous topography in western Mongolia. [ABSTRACT FROM AUTHOR]

Some conceptual models proposed for explaining the Hindu Kush intermediate-depth seismicity assumed that a subhorizontal fracture was migrating laterally, from east toward west, along the strike of a subducted tectonic plate. The present study has identified a distinct cluster of earthquake hypocenters, likely corresponding to the advancing tip of the subhorizontal fracture. Those hypocenters belonged to a set of fairly moderate earthquakes (5.6 ≤ M ≤ 6.5), which had not been, so far, explicitly addressed in the Hindu Kush seismo-tectonic interpretations, and which were proven to be virtually the only events displaying a failure regime characteristic to a laterally propagating breakoff – namely, reverse-fault focal mechanisms with subhorizontal compression axes parallel to the slab strike. A separate, upper-positioned hypocenter cluster was noticed to include all the M w ≥ 7 intermediate-depth earthquakes: it was conjectured, relying on a previously published numerical model, that those strong events could be triggered by upward transfer of the viscoelastic stress induced by the slab pull increase caused by an episode of lateral breakoff advance. At the same time, as the inferred breakoff fracture enables the deeper segment of the plate to detach from the shallower segment, the plate region situated above the severed region is relieved of the gravitational pull that was imposed by the deeper, and currently detached, plate segment. In response to the resulting crustal rebound, the surface topography is expected to exhibit down-tilting to the west. Such an anticipation seems to be confirmed by the catchments of several streams which flow roughly perpendicular to the intermediate-depth earthquakes epicentral domain: relevant geomorphic indices (the swath profile average and maximum elevation curves; the transverse hypsometric integral – THi ; the transverse topographic symmetry factor – T -vector) computed for the concerned valleys consistently suggested larger uplift rates in the east, as compared to those manifest further to the west. [Display omitted] • The Hindu Kush intermediate-depth seismicity could mirror a laterally tearing slab • A distinct cluster of events likely indicates the westward-migrating tip of the tear • These are virtually the only events displaying thrust-faulting with along-slab P axes • As breakoff advances to the W, earth crust in the E is partly relieved of slab pull • The resulting land surface tilting is mirrored by stream catchments asymmetry [ABSTRACT FROM AUTHOR]

Abstract: The Scotia Sea in the South Atlantic holds a prominent position in geodynamics, because it has been proposed as a potential outlet of asthenosphere from under the shrinking Pacific into the mantle beneath the opening Atlantic. Shear wave splitting and geochemical studies have previously tested this hypothesis. Here, we take a different approach by calculating present-day dynamic topography of the region in search for a systematic trend in dynamic topography decreasing from west to east in response to a flow-related pressure gradient in the sublithospheric mantle. To this end, we reconstruct the kinematic history of the Scotia Sea, which is characterized by complex back-arc spreading processes active on a range of time scales. Our plate reconstructions allow us to derive an oceanic age-grid and to calculate the associated residual (dynamically maintained) topography of the Scotia Sea by comparing present-day isostatically corrected topography with that predicted from our reconstruction. The results provide no indication for a systematic trend in dynamic topography and we conclude that the material needed to supply the growing subatlantic mantle must be derived from elsewhere. [Copyright &y& Elsevier]

Abstract: The relief around subduction zones results from the interplay of dynamic processes that may locally exceed the (iso)static contributions. The viscous dissipation of the energy in and around subduction zones is capable of generating kilometer scale vertical ground movements. In order to evaluate dynamic topography in a self-consistent subduction system, we carried out a set of laboratory experiments, wherein the lithosphere and mantle are simulated by means of Newtonian viscous materials, namely silicone putty and glucose syrup. Models are kept in their most simple form and are made of negative buoyancy plates, of variable width and thickness, freely plunging into the syrup. The surface of the model and the top of the slab are scanned in three dimensions. A forebulge systematically emerges from the bending of the viscous plate, adjacent to the trench. With a large wavelength, dynamic pressure offsets the foreside and backside of the slab by ~500m on average. The suction, that accompanies the vertical descent of the slab depresses the surface on both sides. At a distance equal to the half-width of the slab, the topographic depression amounts to ~500m on average and becomes negligible at a distance that equals the width of the slab. In order to explore the impact of slab rollback on the topography, the trailing edge of the plates is alternatively fixed to (fixed mode) and freed from (free mode) the end wall of the tank. Both the pressure and suction components of the topography are ~30% lower in the free mode, indicating that slab rollback fosters the dynamic subsidence of upper plates. Our models are compatible with first order observations of the topography around the East Scotia, Tonga, Kermadec and Banda subduction zones, which exhibit anomalous depths of nearly 1km as compared to adjacent sea floor of comparable age. [Copyright &y& Elsevier]

Abstract: It is well documented that the Cenozoic progressive flooding of Australia, contemporaneous with a eustatic sea level fall, requires a downward tilting of the Australian Plate towards the SE Asian subduction system. Previously, this large-scale, mantle-convection driven dynamic topography effect has been approximated by computing the time-dependent vertical shifts and tilts of a plane, but the observed subsidence and uplift anomalies indicate a more complex interplay between time-dependent mantle convection and plate motion. We combine plate kinematics with a global mantle backward-advection model based on shear-wave mantle tomography, paleogeographic data, eustatic sea level estimates and basin stratigraphy to reconstruct the Australian flooding history for the last 70Myrs on a continental scale. We compute time-dependent dynamic surface topography and continental inundation of a digital elevation model adjusted for sediment accumulation. Our model reveals two evolving dynamic topography lows, over which the Australian plate has progressively moved. We interpret the southern low to be caused by sinking slab material with an origin along the eastern Gondwana subduction zone in the Cretaceous, whereas the northern low, which first straddles northern Australia in the Oligocene, is mainly attributable to material subducted north and northeast of Australia. Our model accounts for the Paleogene exposure of the Gulf of Carpentaria region at a time when sea level was much higher than today, and explains anomalous Late Tertiary subsidence on Australia''s northern, western and southern margins. The resolution of our model, which excludes short-wavelength mantle density anomalies and is restricted to depths larger than 220 km, is not sufficient to model the two well recorded episodes of major transgressions in South Australia in the Eocene and Miocene. However, the overall, long-wavelength spatio-temporal pattern of Australia''s inundation record is well captured by combining our modelled dynamic topography with a recent eustatic sea level curve. We suggest that the apparent Late Cenozoic northward tilting of Australia was a stepwise function of South Australia first moving away northwards from the Gondwana subduction-related dynamic topography low in the Oligocene, now found under the Australian–Antarctic Discordance, followed by a drawing down of northern Australia as it overrode a slab burial ground now underlying much of the northern half of Australia, starting in the Miocene. Our model suggests that today''s geography of Australia is strongly dependent on mantle forces. Without mantle convection, which draws Australia down by up to 300m, nearly all of Australia''s continental shelves would be exposed. We conclude that dissecting the interplay between eustasy and mantle-driven dynamic topography is critical for understanding hinterland uplift, basin subsidence, the formation and destruction of shallow epeiric seas and their facies distribution, but also for the evolution of petroleum systems. [Copyright &y& Elsevier]

Abstract: The regional and continental scale dynamics of North America and vicinity are explored using a high-resolution model of mantle flow. The model is constrained by simultaneously inverting global seismic and mantle convection data sets and it includes an explicit treatment of the positive chemical buoyancy of the continental tectosphere. Moreover, it adopts a depth-dependent mantle viscosity structure which reconciles both glacial isostatic adjustment (GIA) and convection data. The flow model successfully reproduces plate velocities and observations of surface gravity and topography, including the continent-scale quasi-linear depression (after corrections for GIA and crustal heterogeneity) extending from northern Alaska to Venezuela. The predictions also match lithospheric flow and stress fields inferred from local and regional measurements of seismic anisotropy and surface deformation. We demonstrate that these signals are largely driven by viscous flow coupled to density anomalies in the deep portions of the upper mantle and within the lower mantle, where the latter may be associated with the descent of the ancient Kula–Farallon plate system and an active mantle upwelling below the Pacific margin of the North American plate. More importantly, the flow calculations elucidate how these large-scale heterogeneities give rise to regional-scale flow and stress patterns below the southwestern U.S. and below the central U.S. [Copyright &y& Elsevier]