Dietmar Müller

There are a significant number of image processing methods that have been developed during the past decades for detecting anomalous areas, such as hydrothermal alteration zones, using satellite images. Among these methods, dimensionality reduction or transformation techniques are known to be a robust type of methods, which are helpful, as they reduce the extent of a study area at the initial stage of mineral exploration. Principal component analysis (PCA), independent component analysis (ICA), and minimum noise fraction (MNF) are the dimensionality reduction techniques known as multivariate statistical methods that convert a set of observed and correlated input variables into uncorrelated or independent components. In this study, these techniques were comprehensively compared and integrated, to show how they could be jointly applied in remote sensing data analysis for mapping hydrothermal alteration zones associated with epithermal Cu–Au deposits in the Toroud-Chahshirin range, Cent...

The pace of scientific discovery is being transformed by the availability of 'big data' and open access, open source software tools. These innovations open up new avenues for how scientists communicate and share data and ideas with each other and with the general public. Here, we describe our efforts to bring to life our studies of the Earth system, both at present day and through deep geological time. The GPlates Portal (portal.gplates.org) is a gateway to a series of virtual globes based on the Cesium Javascript library. The portal allows fast interactive visualization of global geophysical and geological data sets, draped over digital terrain models. The globes use WebGL for hardware-accelerated graphics and are cross-platform and cross-browser compatible with complete camera control. The globes include a visualization of a high-resolution global digital elevation model and the vertical gradient of the global gravity field, highlighting small-scale seafloor fabric such as...

A drastic change in plate tectonics and mantle convection occurred around 50 Ma as exemplified by the prominent Hawaiian– Emperor Bend. Both an abrupt Pacific Plate motion change and a change in mantle plume dynamics have been proposed to account for the Hawaiian–Emperor Bend, but debates surround the relative contribution of the two mechanisms. Here we build kinematic plate reconstructions and high-resolution global dynamic models to quantify the amount of Pacific Plate motion change. We find Izanagi Plate subduction, followed by demise of the Izanagi–Pacific Ridge and Izu–Bonin–Mariana subduction initiation alone, is incapable of causing a sudden change in plate motion, challenging the conventional hypothesis on the mecha- nisms of Pacific Plate motion change. Instead, Palaeocene slab pull from Kronotsky intraoceanic subduction in the northern Pacific exerts a northward pull on the Pacific Plate, while its Eocene demise leads to a sudden 30–35° change in plate motion, accounting for about half of the Hawaiian–Emperor Bend. We suggest the Pacific Plate motion change and hotspot drift due to plume dynamics could have contributed nearly equally to the formation of the Hawaiian–Emperor Bend. Such a scenario is con- sistent with available constraints from global plate circuits, palaeomagnetic data and geodynamic models.

Widespread flooding of the Australian continent during the Early Cretaceous, referred to as the Eromanga Sea, deposited extensive shallow marine sediments throughout the Great Artesian Basin (GAB). This event had been considered 'out of sync' with eustatic sea level and was instead solely attributed to dynamic sub

We present the newly developed pyGPlates application programming interface (API), and showcase two recent use-cases demonstrating some of the new workflows available to users. The pyGPlates API is a library of high- level GPlates functions available for use in the open-source Python programming language (www.python.org). The library contains much of the existing GPlates application functionality, allowing for data processing, spatial and temporal reconstructions, feature creation and interrogation, and model analysis externally from within Python scripts. This new workflow provides a framework to incorporate GPlates functionality into existing external Python-based analyses at the code level. The first use-case demostrates the use of Python-pyGPlates framework to establish a remote connection to the Magnetics Information Consortium (MagIC) online paleomagnetics database, extract and process selected data, then automatically generate both GPlates GPML and GMAP VGP files for input and...

Carbon capture and storage (CCS) is regarded as a promising strategy for mitigating global warming. A 19% CCS contribution to CO 2 reduction by 2050, as envisaged by the International Energy Agency, would require the construction of thousands of CCS sites by the 2030s and beyond. CO 2 storage may need to last for tens of thousands of years to avoid potential global warming and major Earth system changes, and a critical site selection criterion will be the likelihood of future escape of stored CO 2 due to fault reactivation. However, future long-term intraplate stress field changes have not been considered in this context. Here we focus on Australia, where 61 potential CCS sites have been proposed, and model the evolving intraplate stress field due to the future growth of tectonic collisional forces north of Australia. Counter intuitively, the largest changes are predicted for some parts of western, central and southeast Australia, all regions far away from plate boundaries, reflecting the non-linear interaction of plate boundary forces with a geologically heterogeneous continent. We suggest that at least ten suggested CCS sites are located in regions where major changes of in situ stress regimes can be expected in the next 100,000 years, requiring a careful evaluation of potential future fault reactivation and a breach of reservoir seals. Our results highlight the importance of considering future intraplate stress field changes for selecting CCS sites, particularly within continental regions affected by ongoing mountain building processes including Australia, India, South America, Asia and southern Europe.

Deep-sea carbonate deposition is a complex process that is encapsulated in the carbonate compensation depth (CCD)-a facies boundary separating calcareous sediments from noncarbonates. Knowing how the CCD has varied over time is important for understanding and predicting the distribution of seafloor sediments and assessing their role in the global carbon cycle. We focus on the South Atlantic Ocean where the most recent CCD curve is based on Deep Sea Drilling Project (DSDP) Leg 73 sites drilled in 1980 in the South Atlantic Ocean. We compute the South and central South Atlantic CCD from the Late Cretaceous to the present day using updated age models from 45 DSDP and Ocean Drilling Program sites and backtracking with lithology-specific decompaction, eustasy, and dynamic topography. Our models extend further back in time and show more fluctuations than previous reconstructions, with the CCD varying by hundreds of meters during a span of 2-3 m.y. The addition of eustasy and dynamic topography deepens the CCD by as much as 500 m between 74 Ma and 45 Ma, and by ∼200 m during the Cenozoic. The central South Atlantic CCD diverges from the average South Atlantic CCD during the Eocene and Miocene, when it was ∼1 km shallower. These regional deviations may be due to changes in primary productivity and/or carbonate dissolution leading to reduced carbonate accumulation rates. Our CCD curves highlight the importance of regional processes in carbonate deposition across the South Atlantic and provide improved constraints for the modeling of geochemical cycles.

Although global circulation models (GCMs) have been used for the reconstruction of precipitation for selected geological time slices, there is a lack of a coherent set of precipitation models for the Mesozoic-Cenozoic period (the last 250 million years). There has been dramatic climate change during this time period capturing a supercontinent hothouse climate, and continental breakup and dispersal associated with successive greenhouse and ice-house climate periods. We present an approach that links climate-sensitive sedimentary deposits such as coal, evaporites and glacial deposits to a global plate model, reconstructed paleo-elevation maps and high-resolution GCMs via Bayesian machine learning. We model the joint distribution of climate-sensitive sediments and annual precipitation through geological time, and use the dependency between sediments and precipitation to improve the model's predictive accuracy. Our approach provides a set of 13 data-driven global paleo-precipitation maps between 14 and 249 Ma, capturing major changes in long-term annual rainfall patterns as a function of plate tectonics, paleo-elevation and climate change at a low computational cost.

Deep-sea carbonate deposition is a complex process that is encapsulated in the carbonate compensation depth (CCD)-a facies boundary separating calcareous sediments from noncarbonates. Knowing how the CCD has varied over time is important for understanding and predicting the distribution of seafloor sediments and assessing their role in the global carbon cycle. We focus on the South Atlantic Ocean where the most recent CCD curve is based on Deep Sea Drilling Project (DSDP) Leg 73 sites drilled in 1980 in the South Atlantic Ocean. We compute the South and central South Atlantic CCD from the Late Cretaceous to the present day using updated age models from 45 DSDP and Ocean Drilling Program sites and backtracking with lithology-specific decompaction, eustasy, and dynamic topography. Our models extend further back in time and show more fluctuations than previous reconstructions, with the CCD varying by hundreds of meters during a span of 2-3 m.y. The addition of eustasy and dynamic topography deepens the CCD by as much as 500 m between 74 Ma and 45 Ma, and by ∼200 m during the Cenozoic. The central South Atlantic CCD diverges from the average South Atlantic CCD during the Eocene and Miocene, when it was ∼1 km shallower. These regional deviations may be due to changes in primary productivity and/or carbonate dissolution leading to reduced carbonate accumulation rates. Our CCD curves highlight the importance of regional processes in carbonate deposition across the South Atlantic and provide improved constraints for the modeling of geochemical cycles.

The extraction of tectonic lineaments from digital satellite data is a fundamental application in remote sensing. The location of tectonic lineaments such as faults and dykes are of interest for a range of applications, particularly because of their association with hydro- thermal mineralization. Although a wide range of applications have utilized computer vision techniques, a standard workflow for appli- cation of these techniques to tectonic lineament extraction is lack- ing. We present a framework for extracting tectonic lineaments using computer vision techniques. The proposed framework is a combination of edge detection and line extraction algorithms for extracting tectonic lineaments using optical remote sensing data. It features ancillary computer vision techniques for reducing data dimensionality, removing noise and enhancing the expression of lineaments. The efficiency of two convolutional filters are compared in terms of enhancing the lineaments. We test the proposed frame- work on Landsat 8 data of a mineral-rich portion of the Gascoyne Province in Western Australia. To validate the results, the extracted lineaments are compared to geologically mapped structures by the Geological Survey of Western Australia (GSWA). The results show that the best correlation between our extracted tectonic lineaments and the GSWA tectonic lineament map is achieved by applying a minimum noise fraction transformation and a Laplacian filter. Application of a directional filter shows a strong correlation with known sites of hydrothermal mineralization. Hence, our method using either filter can be used for mineral prospectivity mapping in other regions where faults are exposed and observable in optical remote sensing data.

Anomalous topographic swells and Cenozoic volcanism in east Africa have been associated with mantle plumes. Several models involving one or more fixed plumes beneath the northeastward migrating African plate have been suggested to explain the space-time distribution of magmatism in east Africa. We devise paleogeographically constrained global models of mantle convection and, based on the evolution of flow in the deepest lower mantle, show that the Afar plume migrated southward throughout its lifetime. The models suggest that the mobile Afar plume provides a dynamically consistent explanation for the spatial extent of the southward propagation of the east African rift system (EARS), which is difficult to explain by the northeastward migration of Africa over one or more fixed plumes alone, over the last %45 Myr. We further show that the age-progression of volcanism associated with the southward propagation of EARS is consistent with the apparent surface hotspot motion that results from southward motion of the modelled Afar plume beneath the northeastward migrating African plate. The models suggest that the Afar plume became weaker as it migrated southwards, consistent with trends observed in the geochemical record.

Polymetallic nodules found on the abyssal plains of the oceans represent one of the slowest known geological processes, and are a source of critical and rare metals for frontier technologies. A quantitative assessment of their occurrence worldwide has been hampered by a research focus on the northeastern Pacific Ocean and the lack of a global open-access data set of nodules. We have compiled a global data set of >10,000 seabed nodule and control samples, and combine it with digital grids of key environmental parameters to generate a predictive machine-learning model of nodule occurrence. In order of decreasing parameter ranking, we find that nodules are associated with very low sedimentation rates (< 0.5 cm/k.y.), moderately high oxygen values (150 and 210 mmol/m3), lithologies of clay followed by calcareous ooze, low summer surface productivity (<300 mgC/m2/day), low benthic biomass concentration (<1 log mgC/m2), water depths >4500 m, and low total organic carbon content (0.3–0.5 wt%). Com- peting hypotheses for nodule sustention and thus continued growth on the seafloor are the removal of sediment by bottom-water currents and biological activity. Using a high-resolution eddy-resolving ocean circulation model, we find that the bottom-current speeds over nodule fields are too low (<5 cm/s) to remove sediment, implicating the activity of epibenthic mega- fauna as the most likely mechanism. Our global nodule probability map combined with the assessment of a range of environmental drivers provides an improved basis for decision and policy making in the controversial area of deep-sea exploration.

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.

GPlates is an open-source, cross-platform plate tectonic geographic information system, enabling the interactive manipulation of plate-tectonic reconstructions and the visualization of geodata through geological time. GPlates allows the building of topological plate models representing the mosaic of evolving plate boundary networks through time, useful for computing plate velocity fields as surface boundary conditions for mantle convection models and for investigating physical and chemical exchanges of material between the surface and the deep Earth along tectonic plate boundaries. The ability of GPlates to visualize subsurface 3-D scalar fields together with traditional geological surface data enables researchers to analyze their relationships through geological time in a common plate tectonic reference frame. To achieve this, a hierarchical cube map framework is used for rendering reconstructed surface raster data to support the rendering of subsurface 3-D scalar fields using graphics-hardware-accelerated ray-tracing techniques. GPlates enables the construction of plate deformation zones-regions combining extension, compression, and shearing that accommodate the relative motion between rigid blocks. Users can explore how strain rates, stretching/shortening factors, and crustal thickness evolve through space and time and interactively update the kinematics associated with deformation. Where data sets described by geometries (points, lines, or polygons) fall within deformation regions, the deformation can be applied to these geometries. Together, these tools allow users to build virtual Earth models that quantitatively describe continental assembly, fragmentation and dispersal and are interoperable with many other mapping and modeling tools, enabling applications in tectonics, geodynamics, basin evolution, orogenesis, deep Earth resource exploration, paleobiology, paleoceanography, and paleoclimate. Plain Language Summary The GPlates virtual globe software provides the capability to reconstruct geodata attached to tectonic plates to develop and modify models that describe how the plates and their boundaries have evolved through time. It allows users to deform plates and to visualize surface tectonics in the context of convecting mantle structure and evolution by importing seismic tomography models or outputs from geodynamic models. GPlates applications include tectonics, geodynamics, basin evolution, orogenesis, deep Earth resource exploration, paleobiology, paleoceanography, and paleoclimate. The software is enabling end-users in universities, government organizations, industry, and schools to explore the evolution of planet Earth on their desktop.

Published models for the plate tectonic evolution of the Western Indian Ocean suggest that the Southern Mascarene Basin opened by oceanic crustal accretion between the continental margins of southwestern India and southeastern Madagascar. However, with the cessation of the Mascarene Basin spreading centre followed by a ridge jump resulting in the opening of the Carlsberg Ridge, almost all the traces of India-Madagascar divergence were carved away from the Indian Plate and attached to the African Plate. According to some recent studies, the Chain-Kairali Escarpment, a prominent feature on the southwestern continental margin of India, is possibly the only trace of India-Madagascar divergence that remained on the Indian Plate. But the exact conjugate correspondence of this feature on the Madagascar side is uncertain. Published plate tectonic reconstructions imply that the Vishnu Fracture Zone on the Indian side and the Mauritius Fracture Zone on the Madagascar side are aligned at chron C22ny (∼49.04 Ma). Based on the near collinearity of gravity anomaly trends, the Chain-Kairali Escarpment appears to be the landward extension of the Vishnu FZ. However, at chron C34ny (∼83.0 Ma), the Chain-Kairali Escarpment was in close proximity to the incipient Mahanoro Fracture Zone. In this study we investigate this incompatibility, using an up-to-date compilation of the tectonic elements from the conjugate regions of India and Madagascar and the latest available rotation parameters that describe India-Madagascar separation through a direct India-Seychelles-Madagascar plate circuit. Our revised plate reconstruction model suggests that the Chain-Kairali Escarpment was formed due to the strike-slip motion between the southeast coast of Madagascar and the then southwest coast of India during the initial stages of India-Madagascar breakup. The migration of the Chain-Kairali Escarpment from the proximity of the Mahanoro FZ and aligning with the Vishnu FZ was the result of several successive events. The first among those events was asymmetric crustal accretion in the Mascarene Basin due to ridge propagation, between chrons C34ny (83.0 Ma) to C33ny (∼73.62 Ma). The Chain-Kairali Escarpment and associated crustal weak zones offshore India appear to have facilitated subsequent initiation of the Mauritius FZ and its conjugate Vishnu FZ during a plate reorganization at about chron C33ny (∼73.62 Ma). The cessation of spreading in the Mascarene Basin and development of full extent of the Carlsberg Ridge, shortly after chron C27ny (60.92 Ma), resulted in the initiation of a long transform fault, coinciding with the Vishnu FZ, which connected the Carlsberg Ridge with the spreading centre of the Madagascar Basin. Therefore, the Vishnu FZ and the Chain-Kairali Escarpment are two independent features created during different episodes of evolution of the Western Indian Ocean and the Chain-Kairali Escarpment is not a landward extension of the Vishnu FZ.

Atmospheric carbon dioxide (CO 2) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26 to 32 My whose origin is unknown. Periodicities of 26 to 30 My occur in diverse geological phenomena including mass extinctions, flood basalt volcanism, ocean anoxic events, deposition of massive evaporites, sequence boundaries, and orogenic events and have previously been linked to an extraterrestrial mechanism. The vast oceanic crustal carbon reservoir is an alternative potential driving force of climate fluctuations at these time scales, with hydrothermal crustal carbon uptake occurring mostly in young crust with a strong dependence on ocean bottom water temperature. We combine a global plate model and oceanic paleo-age grids with estimates of paleo-ocean bottom water temperatures to track the evolution of the oceanic crustal carbon reservoir over the past 230 My. We show that seafloor spreading rates as well as the storage, subduction, and emission of oceanic crustal and mantle CO 2 fluctuate with a period of 26 My. A connection with seafloor spreading rates and equivalent cycles in subduction zone rollback suggests that these periodicities are driven by the dynamics of subduction zone migration. The oceanic crust-mantle carbon cycle is thus a previously overlooked mechanism that connects plate tectonic pulsing with fluctuations in atmospheric carbon and surface environments.

The pyBacktrack software package allows the backtracking of the paleo-water depth of ocean drill sites, providing a framework for reconstructing the accumulation history of sediment components through time. The software incorporates the effects of decompaction of common marine lithologies and allows backtracking of sites on both oceanic and continental crust. Backtracking on ocean crust is based on a user-selected lithospheric age-depth model and the present-day unloaded basement depth. Backtracking on continental crust is based on syn-rift and post-rift subsidence that is modeled using the total sediment thickness at the site and the timing of the transition from rifting to thermal subsidence. On sites that did not penetrate basement, the age-coded stratigraphy is supplemented with a synthetic stratigraphic section that represents the undrilled section, whose thickness is estimated using a global sediment thickness map. This is essential for estimating the decompacted thickness of the total sedimentary section, and thus bathymetry, through time. PyBacktrack further allows the consideration of the effects of mantle-convection driven dynamic topography on paleo-water depth. The user can select one of the dynamic topography models bundled with pyBacktrack or add other models. PyBacktrack runs on all platforms with a Python 2.7 and a pyGPlates installation and is available via Github.

Although many sources of atmospheric CO 2 have been estimated, the major sinks are poorly understood in a deep-time context. Here we combine plate reconstructions, the eruption ages and outlines of Large Igneous Provinces (LIPs), and the atmospheric CO 2 proxy record to investigate how their eruptions and weathering within the equatorial humid zone impacted global atmospheric CO 2 since 400 Ma. Wavelet analysis reveals significant correlations between the eruption of the Emeishan LIP (259 Ma), the Siberian Traps (251 Ma), the Central Atlantic Magmatic Province (201 Ma), the second pulse of the North Atlantic Igneous Province (55 Ma), the High Arctic LIP (130 Ma), and the Deccan Traps (65 Ma) and perturbations in atmospheric CO 2. Our analysis also reveals a clear relationship between the weathering of the Central Atlantic Magmatic Province (~200–100 Ma), the Deccan Traps (50–35 Ma), and the Afar Arabian LIP (30–0 Ma) and a significant atmospheric CO 2 drawdown. Our results illustrate the significant role of subaerial LIP emplacement and weathering in modulating atmospheric CO 2 and Earth's surface environments. Plain Language Summary Carbon dioxide in the atmosphere plays a significant role in regulating Earth's climate. There are many processes, which over geologic timescales add to or sequester CO 2 from the atmosphere, and in turn alter Earth's climate. Here we investigate processes involved in the eruption and weathering of Large Igneous Provinces (LIPs), massive nonexplosive volcanic eruption of basaltic lava and rock. During eruptions, LIPs contribute significant amounts of CO 2 to the atmosphere in very short periods of geologic time, and subsequently, when basalt is exposed to physical and chemical weathering, the process will draw CO 2 from the atmosphere. We consider both eruptions, and the subsequent latitudinal positions of the LIPs in the context of their weathering, which is most severe at low latitudes due to high tropical precipitation rates. We find that periods of elevated atmospheric CO 2 were related to the eruption of the Emeishan LIP and Siberian Traps (260—240 Ma), the Central Atlantic Magmatic Province (210—190 Ma), and the North Atlantic Igneous Province, High Arctic LIP, and the Deccan Traps (90—60 Ma) and those of lowered CO 2 to be related to weathering of the Central Atlantic Magmatic Province (~200–100 Ma), the Deccan Traps (as it drifted through low latitude regions ~50–35 Ma), and the Afar Arabian LIP (30–0 Ma). Our analysis reveals the significant role LIPs have played in modulating Earth's climate.

Some changes in the topography of eastern China since Late Jurassic times cannot be well explained by lithospheric deformation. Here we analyze global mantle flow models to investigate how mantle-driven long-wavelength topography may have contributed to shaping the surface topography of eastern China. Paleodrainage directions suggest that a southward tilted topography once existed in eastern north China in the latest Jurassic Period, which is different from that at present day (southeastward tilting). Our model dynamic topography reveals a southward tilting topography between 160 and 150 Ma, followed by southeastward tilting and rapid subsidence, which is compatible with paleodrainage directions and tectonic subsidence of the Ordos Basin. The Cretaceous anomalous subsidence of the Songliao and North Yellow Sea basins, as well as the Cenozoic anomalous subsidence of the East China Sea Shelf Basin, can also be explained by dynamic topography. An apatite fission track study in the Taihang Mountains reveals four stages of evolution: Late Jurassic fast unroofing, Cretaceous slow unroofing, early Cenozoic fast unroofing, and late Cenozoic slow unroofing. We propose that mantle flow influenced this surface unroofing because the model predicts Late Jurassic dynamic uplift, Cretaceous dynamic subsidence, early Cenozoic dynamic uplift, and late Cenozoic dynamic subsidence. Apatite fission track data from northern south China are also in reasonable agreement with predicted dynamic topography between 80 and 30 Ma. The spatial and temporal agreement between geological observations and model dynamic topography indicates that mantle flow has had a significant influence in shaping the surface topography of eastern China.

Keywords: contourite sediment drift ocean modelling meridional overturning circulation eddy bottom current Contourite drifts are anomalously high sediment accumulations that form due to reworking by bottom currents. Due to the lack of a comprehensive contourite database, the link between vigorous bottom water activity and drift occurrence has yet to be demonstrated on a global scale. Using an eddy-resolving ocean model and a new georeferenced database of 267 contourites, we show that the global distribution of modern contourite drifts strongly depends on the configuration of the world's most powerful bottom currents, many of which are associated with global meridional overturning circulation. Bathymetric obstacles frequently modify flow direction and intensity, imposing additional finer-scale control on drift occurrence. Mean bottom current speed over contourite-covered areas is only slightly higher (2.2 cm/s) than the rest of the global ocean (1.1 cm/s), falling below proposed thresholds deemed necessary to re-suspend and redistribute sediments (10–15 cm/s). However, currents fluctuate more frequently and intensely over areas with drifts, highlighting the role of intermittent, high-energy bottom current events in sediment erosion, transport, and subsequent drift accumulation. We identify eddies as a major driver of these bottom current fluctuations, and we find that simulated bottom eddy kinetic energy is over three times higher in contourite-covered areas in comparison to the rest o.f the ocean. Our work supports previous hypotheses which suggest that contourite deposition predominantly occurs due to repeated acute events as opposed to continuous reworking under average-intensity background flow conditions. This suggests that the contourite record should be interpreted in terms of a bottom current's susceptibility to experiencing periodic, high-speed current events. Our results also highlight the potential role of upper ocean dynamics in contourite sedimentation through its direct influence on deep eddy circulation.

A B S T R A C T Traditional plate reconstruction methodologies do not allow for plate deformation to be considered. Here we present software to construct and visualize global tectonic reconstructions with deforming plates within the context of rigid plates. Both deforming and rigid plates are defined by continuously evolving polygons. The deforming regions are tessellated with triangular meshes such that either strain rate or cumulative strain can be followed. The finite strain history, crustal thickness and stretching factor of points within the deformation zones are tracked as Lagrangian points. Integrating these tools within the interactive platform GPlates enables specialized users to build and refine deforming plate models and integrate them with other models in time and space. We demonstrate the integrated platform with regional reconstructions of Cenozoic western North America, the Mesozoic South American Atlantic margin, and Cenozoic southeast Asia, embedded within global reconstructions , using different data and reconstruction strategies.

The stretched continental margins of the North Atlantic region record a plate kinematic history dominated by major episodes of extension since the Late Palaeozoic. Accounting for the restoration of this stretched continental crust across the region, and the subsequent derivation of plausible full-fit configurations between these continents, prior to extension, still remains unresolved. Previous plate reconstructions have highlighted difficulties such as determining the amount of extension to be distributed across the multiple episodes of rifting, or defining the distribution of extension across intraplate deformation occurring adjacent to the rifting of two major continents. Here, we implement a new approach to derive a set of total reconstruction poles based on a full-fit, palinspastic restoration of the conjugate margins that considers the rifting evolution of the North Atlantic in a regional plate kinematic context since the Earliest Jurassic. Gravity inversion forms the basis of our regional crustal thickness estimates, and aids in the identification of thinned continental crust. Our crustal restoration estimates are computed in multiple phases along margin segments in accordance with the timing of their major rifting episodes. Our model predicts a full-fit, prerift, palaeogeographic position of all the major continents across the North Atlantic; and predicts a time-dependent evolution of multiple phases of extension including regional divergence directions, consistent with previous observations. Our plate model represents a new approach to plate kinematic reconstructions incorporating the application of a multiphase restoration methodology applied in a major regional context, constrained by the synthesis of several different geological and geophysical data sets.

Tracing sedimentation through time on existing and vanished seafloor is imperative for constraining long-term eustasy and for calculating volumes of subducted deep-sea sediments that contribute to global geochemical cycles. We present regression algorithms that incorporate the age of the ocean crust and the mean distance to the nearest passive margin to predict sediment thicknesses and long-term decompacted sedimentation rates since 200 Ma. The mean sediment thickness decreases from $220 m at 200 Ma to a minimum of $140 m at 130 Ma, reflecting the replacement of old Panthalassic ocean floor with young sediment-poor mid-ocean ridges, followed by an increase to $365 m at present-day. This increase reflects the accumulation of sediments on ageing abyssal plains proximal to passive margins, coupled with a decrease in the mean distance of any parcel of ocean crust to the nearest passive margin by over 700 km, and a doubling of the total passive margin length at present-day. Mean long-term sedimentation rates increase from $0.5 cm/ky at 160 Ma to over 0.8 cm/ky today, caused by enhanced terrigenous sediment influx along lengthened passive margins, superimposed by the onset of ocean-wide carbonate sedimenta-tion. Our predictive algorithms, coupled to a plate tectonic model, provide a framework for constraining the seafloor sediment-driven eustatic sea-level component, which has grown from $80 to 210 m since 120 Ma. This implies a long-term sea-level rise component of 130 m, partly counteracting the contemporaneous increase in ocean basin depth due to progressive crustal ageing.