Abstract Extreme hydroclimates impact sediment fluxes from mountainous catchments to the oceans. Given modern global warming, a challenge is to assess the sensitivity of erosion in mountainous catchments to extreme climate perturbations. Here, we reconstruct paleo‐sedimentary fluxes across an abrupt global warming, the Paleocene‐Eocene Thermal Maximum (PETM, ∼56 Ma), using sedimentary archives and numerical modeling. In the Tremp Basin (Southern Pyrenees, Spain), our results demonstrate that depositional volumetric rates of siliciclastic sediments increased two‐fold during the PETM. According to the BQART and stream power law models, changes in mean annual temperature and precipitation explain only 9%–27% of the flux increase. This comparison between field data and model predictions suggests that even with high uncertainty on paleoclimate data, extreme rainfall events and landslides may have been crucial sediment generation processes during the PETM. This is consistent with predictions of enhanced climate variability in a warmer world, leading to significant sediment flushing.

Summary To test the mantle dynamic control in this topographic pattern of Africa and to discuss their effects on the relief growth and their consequences on the source-to-sink systems, we compiled new style palaeogeographic maps at Africa-scale with a first attempt of palaeotopographic reconstructions and quantification. These observations suggest that the South African superplume had a significant role in the growth of these topographies since 40 Ma, with a propagation of the superplume toward the north and a progressive spreading below the North African lithosphere during the locking of Africa Plate with Eurasia Plate. The initiation of the uplift at 40 Ma localized the erosion along the “coastal” plains, enhanced from 40 Ma to today by isostatic rebounds and modulated by plate-scale deformation and/or major climatic changes.

Paleogeographic maps are essential tools for understanding Earth system dynamics. They provide boundary conditions for climate and geodynamic modelling, for analysing surface processes and biotic interactions. However, the temporal and spatial distribution of key features such as seaways and mountain belts that govern climate changes and biotic interchange differ between various paleogeographies that require regular updates with new data and models. We developed a reproducible and systematic approach to paleogeographic reconstruction and provide a set of worldwide Cenozoic paleogeographic maps at 60, 40 and 20 Ma. We followed a six-stage methodology that integrates an extensive review of geological data into a coherent plate tectonic model using the open source software GPlates. (1) We generated a global plate kinematic model, and reconstructed intensely-deformed plate boundaries using a review of structural, paleomagnetic and other geologic data in six key regions: the Andes, the North American Cordillera, the Scotia Arc, Africa, the Mediterranean region and the Tibetan-Himalayan collision zone. (2) We modified previously published paleobathymetry in several regions where continental and oceanic crust overlap due to differences in the plate models. (3) We then defined paleoshorelines using updated fossil and geologic databases to locate the terrestrial to marine transition. (4) We applied isostatic compensation in polar regions and global eustatic sea level adjustments. (5) Paleoelevations were estimated using a broad range of data including thermochronology and stable isotopes, combined with paleobotanical (mostly pollen and leaf physiognomy), structural and geomorphological data. We address ongoing controversies on the mechanisms and chronology of India-Asia collision by providing alternate reconstructions for each time slice. We finally discuss the implications of our reconstructions on the Cenozoic evolution of continental weatherability and review methodological limitations and potential improvements. Future addition of new data, tools and reconstructions can be accommodated through a dedicated interactive website tool (https://map.paleoenvironment.eu/) that enables users to interactively upload and download data and compare with other models, and generate their own plots. Our aim is to regularly update the models presented here with new data as they become available.

Pliocene and Pleistocene sediments from West Turkana (Kenya, East African Rift System) form emblematic syn-rift successions for understanding the evolution of extensional basin and continental rifting. They also constitute world-renowned fossil-bearing strata from which >500 hominin fossils were discovered over the past decades, with >100 inventoried archeological sites. However, associated sedimentary dynamics and architectures as well as paleoenvironments are only partially reconstructed and the relative contribution of climate and tectonism to paleoenvironmental change over time remains unclear. Here, through the interpretation of sedimentary facies, the delineation of sequences and the analysis of delta C-13 in soil carbonates, we provide the first exhaustive reconstruction from similar to 4.00 to similar to 0.75 Ma of (i) fluctuations of the paleolake that occupied the Turkana Depression, (ii) the successive sedimentary dynamics and related paleolandscapes that characterized the West Turkana area and (iii) respective roles of climate and tectonism in the sedimentation. We show evidence for seven major transgression-regression (T-R) cycles between similar to 4.00 and similar to 0.75 Ma superimposed locally by lower amplitude T-R cycles. Comparing the sedimentological interpretations and the delta C-13 values in soil carbonates (literature data), we reveal that fluctuations of rainfall over the Ethiopian Dome, which hosts the drainage basin of the Omo River - the main tributary of Lake Turkana - controlled high-amplitude lake level fluctuations during the PlioPleistocene period. We also demonstrate that vegetation and tree cover evolved differently in the Omo Valley and West Turkana. Furthermore we outline that two different sedimentary systems reflecting two distinct modes of sedimentation alternated through times in the West Turkana area as a response to the variations in sediment supply coming from the western rift shoulder (i.e. Lapurr Range) that alternatively generated wave- or river-dominated sedimentary systems. In conclusion, we reveal that climate regulated water-input, paleolake waterlevel fluctuations and vegetation. Tectonism determined sediment supply to the basin controlled in West Tur kana by pulses of increased activity of the main border fault (i.e., the Murua Rith Lapurr Fault).

The marine sedimentary record contains unique information about the history of erosion, uplift and climate of the adjacent continent. Inverting this record has been the purpose of many numerical studies. However, limited attention has been given to linking continental erosion to marine sediment transport and deposition in large-scale surface process evolution models. Here we present a new numerical method for marine sediment transport and deposition that is directly coupled to a landscape evolution algorithm solving for the continental fluvial and hillslope erosion equations using implicit and O(N) algorithms. The new method takes into account the sorting of grain sizes (e.g., silt and sand) in the marine domain using a non-linear multiple grain-size diffusion equation and assumes that the sediment flux exported from the continental domain is proportional to the bathymetric slope. Specific transport coefficients and compaction factors are assumed for the two different grain sizes to simulate the stratigraphic architecture. The resulting set of equations is solved using an efficient (O(N) and implicit) algorithm. It can thus be used to invert stratigraphic geometries using a Bayesian approach that requires a large number of simulations. This new method is used to invert the sedimentary geometry of a natural example, the Ogooué Delta (Gabon), over the last ∼5 Myr. The objective is to unravel the set of erosional histories of the adjacent continental domain compatible with the observed geometry of the offshore delta. For this, we use a Bayesian inversion scheme in which the misfit function is constructed by comparing four geometrical parameters between the natural and the simulated delta: the volume of sediments stored in the delta, the surface slope, the initial and the final shelf lengths. We find that the best-fit values of the transport coefficients for silt in the marine domain are in the range of 300−500 m2/yr, in agreement with previous studies on offshore diffusion. We also show that, in order to fit the sedimentary geometry, erosion rate on the continental domain must have increased by a factor of 6 to 8 since 5.3 Ma.

Summary Although contourites and mixed turbidite/contourite depositional systems are significant to the oil industry, they are still relatively poorly known by this sector, and there is no present-day accepted sedimentological model for sandy contourites. Our goal here is to better understand the possibility of occurrence of contouritic sands susceptible to form potential reservoirs for hydrocarbons, and therefore possible new plays. After the Gulf of Cadiz ( Hernández-Molina et al., 2013 ) and the Brazilian margin ( Mutti et al., 2014 ), the discovery of coarse granulometry contourite facies in Plio-pleistocene deposits offshore Mozambique is a great step toward the proof of concept of reservoir potential for these objects. The results presented derive from the Pamela (PAssive Margin Exploration Laboratories) project, led by Ifremer and TOTAL in collaboration with Universités de Bretagne Occidentale, Rennes-1, P&M Curie, CNRS and IFPEN. First class outcome, the PAMELA-MOZ-3 cruise has revealed occurrence of coarse-grained contourite facies deposited in a condensed layer wedging on a contourite terrace. Sandy contourite facies (siliciclastic or carbonate) is now proved to occur where favorable conditions gather. Consolidated with state-of-the art techniques of subsurface data interpretation, the new model integrating geometrical and amplitude characters should give keys to help interpreters predict the reservoir potential of contourites.

Summary The topography of Austral and Eastern Africa (including Madagascar) is characterized by very long wavelength (several thousands of kilometers) plateaus and domes related to mantle dynamics: the Southern (Kalahari) Plateau, the Eastern (Kenyan) African and Ethiopian Domes and Madagascar Plateau. Our objective here is to discuss the relationships between the plateaus and domes growth since Early Cretaceous times, the climate (and mainly the precipitation) changes and the sediment supply along the passive margins.

Summary The South African Plateau (SAP) is the world’s largest non-orogenic plateau. It forms a large-scale topographic anomaly which rises from sea level to > 1000 m. Most mechanisms proposed to explain its elevation gain imply mantle processes. The age of the uplift and the different steps of relief growth are still debated. On one hand, a Late Cretaceous uplift is supported both by thermochronological studies and sedimentary flux quantifications. On the other hand, geomorphological studies suggest a Late Cenozoic uplift scenario (<30 Ma). However few attentions were paid to the evolution of the overall geomorphic system, from the upstream erosional system to the downstream depositional system. This study is based on two different approaches: - Onshore, on the mapping and chronology of all the macroforms (weathering surfaces, pediments and pediplains, incised rivers, wave-cut platforms) dated by intersection with the few preserved sediments and the volcanics. - Offshore, on a more classical dataset of seismic lines and petroleum wells, coupled with biostratigraphic revaluations (characterization and dating of vertical movements of the margins - sediment volume measurement). The main result of this study is that the SAP is an old Upper Cretaceous relief (90–70 Ma) reactivated during Oligocene (30–15 Ma) times.

Summary The early stage of oil exploration in sedimentary basins is based both on large scale tectono-stratigraphic approach from previous works and conventional imaging data mostly well-logs and 2D seismic. In particular geologists face to the lack of model to be able to better predict the reservoir presence and quality of undrilled basins. The source-to-sink studies (“S2S”) on modern or recent systems are particular interest because they aim to understand and quantify the link from the source/hinterland area (drainage area, nature of the bedrock, climate and topography) to the sink/basin (slope gradient, shelf size, eustasy and sedimentary process). The application of this S2S approach on ancient sedimentary systems is challenging because of the lack of constraints of some controlling factors like the climate, the composition of the source material, the location and altitude of paleo-reliefs or the extent of the drainage area. Our aim is to explore if there is a way to anticipate the impact of the tectonic /geodynamic and climatic evolution of a hinterland on clastic accumulations in the basin and their related mineralogical composition in the basin using the same data-set that can be obtained during an early exploration phase.

We here present geological arguments for the age and the timing of the Madagascar Plateau. This analysis is based on a double, coupled analysis of the onshore geomorphology (stepped planation surfaces) and the offshore margin stratigraphy (seismic stratigraphy, and paleogeography).

Summary We present a new source to sink study of the Zambezi system from the coastal plain to the deep sea fan since early Cretaceous times. Using new seismic data acquired in the Mozambique channel combined with a biochronostratigraphic and paleoclimatic study realised on the cuttings of three industrial wells we provide a new age model in a continuous paleoclimatic frame evolution. The evolution of the Zambezi system may be summarised in four steps : 1) Late Jurassic - Late Cretaceous (Albian): the Zambezi delta is defined by a slight slope with reduced height clinoforms, 2) Late Cretaceous - Cenozoic: the system Zambezi/Limpopo - Save prograded. The location of two main depocentres traduce the distinction of the Limpopo-Save basin from the Zambezi basin at the end of the early Cretaceous and two sedimentary supplies: from the Bushveld and the paleo Zambezi, 3) Early Paleocene - Late Eocene: a main transgression flooded the present day coast allowing the initiation of a carbonate platform, 4) Oligocene - Present day: birth of the modern Zambezi delta with low siliciclastic supply during Oligocene times, increasing during Miocene times linked to the East African Rift System.

Summary The measurement of deposited volumes of sediments is based on the basin infilling study which consists on both subsurface data and outcrops analysis. The main objectives were (1) to obtain an age model based on onshore mammals biozones and (2) to reconstruct the 3D architecture of the rift using sequence stratigraphy correlations and seismic data interpretation. Deformation evolution of the rift through times is characterized according to seismic interpretation and to the distribution and quantification of the accommodation for several time intervals. Two major unconformities were identified and dated at 6.2 Ma (Uppermost Miocene) and 2.7 Ma (Pliocene-Pleistocene boundary), coeval with major subsidence and climatic changes. The landforms analysis is based on the characterization, relative dating and 3D mapping of Ugandan landforms which consist of stepped planation surfaces and incised valleys. The sediment budget is successful with, between 17 and 2.5 Ma, an excess of 16 % of upstream eroded material compared to the sediment volume deposited that can be explained by the chemical erosion prevailing at this period in Central Africa. The significant (60%) opposite difference between 2.7 and 0 Ma may be the consequence of a high sediment supply resulting from the erosion of the uplifted Ruwenzori Mountains.

Here, the larger foraminifera found in Middle Eocene-Early Miocene rocks from Dhofar (Oman) and Socotra Island (Yemen) are studied in detail. The architectural analysis leads to the description of five new genera and nine new species: five agglutinated foraminifera, Pseudolituonella robineti n. sp., Socotraella ashawqi n. gen. n. sp., Pseudoaccordiella ayaki n. gen. n. sp., Barattolites andhuri n. sp., and Rogerella aydimi n. gen. n. sp.; and four porcellaneous foraminifera, Idalina grelaudae n. sp., Idalina pignattii n. sp., Macetadiscus incolumnatus n. gen. n. sp., and Omanodiscus tenuissimus n. gen. n. sp. The larger foraminifera identified in a composite section located in western Dhofar, in the Shuwaymiyah section located in eastern Dhofar, and in the Wadi Ayak section located on Socotra Island have facilitated the identification of the following larger foraminifera zones: SBZ 14–SBZ 15 (middle Lutetian), SBZ 16 (late Lutetian), SBZ 17 (Bartonian), SBZ 18 (latest Bartonian-earliest Priabonian), SBZ 19–SBZ 20 (Priabonian), SB 21–SB 22A (Rupelian), SB 22B–SB 23 (Chattian), and SB 24 (Aquitanian). All these data permit to assess the age of the following lithostratigraphic units: Dammam Fm.—Andhur Mb. lower Lutetian?-middle Lutetian age (SBZ 13?–SBZ 14 partim ), Qara Mb. middle Lutetian (SBZ 14–SBZ 15), and Uyun Mb. upper Lutetian (SBZ 16); Aydim Fm.—Heiron Mb. Bartonian (SBZ 17), Moosak Mb. upper Bartonian-Priabonian (SBZ 18–SBZ 20), Tagut Mb. Priabonian (SBZ 19–SBZ 20), and Haluf Mb. Priabonian (SBZ 19–SBZ 20) to lower Rupelian (SBZ 21) on Socotra Island; Ashawq Fm. Rupelian (SB 21–SB 22A); and Mughsayl Fm. Chattian-Aquitanian (SB 23–SB 24).

The uppermost Cretaceous to early Palaeogene is a period of major deformations of the western part of the Eurasian plate with prominent basin inversions starting from the Coniacian onwards. These deformations occur in a complex geodynamic setting within both the context of the Africa–Eurasia convergence and the North Atlantic opening. While Mesozoic graben inversions have been extensively studied, particularly in Eastern Europe and the North Sea, more gentle deformations that affect thicker crust areas (intracratonic basins and emerged lands) are not as well documented. The objective of this study is to constrain the exact timing, type, and magnitude of the early Palaeogene deformations affecting the intracratonic Paris Basin and to integrate them at the western European scale. Low-amplitude deformations are attempted through a high-resolution reconstitution of its stratigraphic record based on well-dated outcrops and well-dated wells, and a high number of well-logs that are correlated using the “stacking pattern” sequence stratigraphic technique. Two orders of sequences are identified (third and fourth order) and correlated throughout the basin. Basin geometric and palaeogeographic reconstitutions are based on sediment thickness and facies analysis. Two-dimensional accommodation space measurements were taken in order to quantify the magnitude of the deformations. Three phases of deformation were recognized. 1. An intra-Maastrichtian–pre-Thanetian (59 Ma) deformation, with major uplift and erosion of the Cretaceous strata with two sub-periods of deformation: Maastrichtian–pre-middle-Danian and Upper Danian–pre-Thanetian long-wavelength deformations. This period of major deformation is coeval with Upper Cretaceous/pre-Danian compressive deformations linked to the Africa–Eurasia convergence in southern France and with volcanic activity from the North Atlantic to Massif Central and the Rhenish Shield during the Palaeocene. 2. An early Ypresian (55.1–54.3 Ma) medium-wavelength deformation ( × 10 km), here reported to be a stress rearrangement related to the onset of the North Atlantic opening. 3. An uppermost Ypresian (49.8 Ma) long-wavelength deformation ( × 100 km), contemporaneous with flexural compressive deformations in the Aquitaine Basin (Pyrenean deformation), and related to the Iberia–Eurasia convergence.

In the Mesozoic–Cenozoic continental deposits of the Tian Shan area, two main levels containing pedogenic carbonates have been identified on both the southern and northern foothills of the range: one in the Upper Jurassic series and one in the Upper Cretaceous–Lower Palaeocene series. In order to reconstruct the palaeoenvironmental and palaeotopographic characteristics of the Tian Shan area during these two periods, we measured the oxygen and carbon isotope composition of these pedogenic carbonates (calcrete and nodules). The stable isotope compositions are homogeneous: most δ18O values are between 21 and 25‰ and most δ13C values are between −4 and −6‰. No distinction can be made between the calcrete and nodule isotopic compositions. The constancy of isotopic values across the Tian Shan is evidence of a development of these calcification features in similar palaeoenvironmental conditions. The main inference is that no significant relief existed in that area at the Cretaceous−Palaeogene boundary, implying that most of the present relief developed later, during the Cenozoic. In addition to the pedogenic carbonates, few beds of limestones interstratified in the Jurassic series of the southern foothills display oxygen and carbon isotope compositions typical of lacustrine carbonates, ruling out brackish water incursion at that period in the region.

The thermal and flexural evolution of passive margins are impacted by the (un)loading effects of erosion/sedimentation processes, which, in turn, affect their relief and sediment accumulation. This complex coupling is recorded by the stratigraphic trend of the associated sedimentary basins, which is controlled by the balance between sediment accumulation, subsidence and eustasy.

The topographic evolution of continents and especially the growth and dismembering of mountain ranges plays a major role in the tectonic evolution of orogenic systems, as well as in regional or global climate changes. A large number of studies have concentrated on the description, quantification and dating of relief building in active mountain ranges. However, deciphering the topographic evolution of a continental area submitted to recurrent tectonic deformation over several hundred millions of years remains a challenge. Here we present a synthesis of the tectonic, geochronological and sedimentological data available on the intracontinental Tian Shan Range to describe its general topographic evolution from Late Palaeozoic to Early Tertiary. We show that this evolution has occurred in two very distinct geodynamic settings, initiating during the Carboniferous in an ocean subduction – continent collision tectonic context before becoming, from Early Permian, purely intra-continental. We show that during most of the Mesozoic, the topography is mostly characterized by a progressive general decrease of the relief. Nonetheless localized, recurrent deformation induced the formation of small-scale reliefs during that period. These deformations were driven by far field effects of possibly several geodynamic processes in a way that still remains to be fully understood.

The thermal and flexural evolution of passive margins is impacted by the (un)loading effects of erosion/sedimentation processes, which, in turn, affect their relief and sediment accumulation. These complex couplings are recorded by the stratigraphic trend of the associated sedimentary basins, which is controlled by the balance between sediment accumulation, subsidence and eustasy.Our objective is to constrain the relative contribution of the factors controlling the mechanical response of the lithosphere and the efficiency of the surface processes on parameters such as the denudation/accumulation and uplift/subsidence history and long-term stratigraphic trends. The novel aspect of our approach is to integrate the evolution of both domains in erosion and in sedimentation, using state of the art modeling of the flexure of the lithosphere including the surface processes (erosion/sedimentation) and the thermal evolution, as well as concepts in sequence stratigraphy.We investigated numerically the post-rift evolution of passive margins, testing the influence of the lithosphere's initial geometries, thermal states and stretching profiles as well as the efficiency of the surface processes. In all simulations, the initial flexural rift-shoulder is eroded away within 10 to 20 Myr. In the following stages, the sedimentary supply and the evolution of the margin are mostly controlled by the flexural response to the thermal relaxation of the isotherms by cooling and the (un)loading mass transfer at the surface. Both the sediment accumulation (controlled by relief relaxation) and the subsidence rates decrease exponentially with time. The evolution of their relative values forms a regressive/transgressive sequence. We show that variations in the efficiency of the surface processes may impact the uplift/subsidence histories and the long-term stratigraphic trend within the same range of magnitude as lithospheric parameters such as pre-rift crust thickness or depth dependency of stretching. The initial crustal thickness is then determinant in the denudation/accumulation history whereas the margin width will impact the uplift/subsidence history the second most. Depth of necking and effective elastic thickness are critical mostly during the initial phase of the margin history (syn- and immediate post-rift) whereas bulk sediment density and lithosphere thickness become critical in the late post-rift. (C) 2013 Elsevier B.V. All rights reserved.

ABSTRACT The terrigeneous sediment budget of passive margin basins records variations in continental relief triggered by either deformation or climate. Consequently, it becomes a major challenge to determine sediment accumulation histories in a large number of basins found in various geodynamic contexts. In this study, we developed a GIS‐based method to determine the sediment budget at the scale of a whole basin (from the upstream continental onlap to the most distal deepest marine deposits) and the associated uncertainties. The volume of sediments preserved in the basin for each time interval was estimated by interpolation between cross‐sections and then corrected from in situ production and porosity to obtain terrigeneous solid volumes. This approach was validated by applying it to Namibia–South African passive margin basins for which independent data are available. We determined by a statistical approach the variances associated with each parameter of the method: the geometrical extrapolation of the section (8–43%), the uncertainties on seismic velocities for the depth conversion (2–10%), on the absolute ages of stratigraphic horizons (0.2–12%), on the carbonate content (0.2–46%) and on remaining porosities estimation (3–5%). Our estimates of the accumulated volumes were validated by comparison with previous estimates at a lower temporal resolution in the same area. We discussed variations in accumulation rates observed in terms of relief variations triggered by climate and/or deformation. The high accumulation rates determined for the Lower Cretaceous, progressively decreasing to a minimum in the Mid‐Cretaceous, are consistent with the progressive relaxation of a rift‐related relief. The following increase to an Upper Cretaceous maximum is consistent with a major relief reorganization driven either by an uplift and/or a change to more humid climate conditions. The lower accumulation rate in the Cenozoic suggests a relief reorganization of lesser amplitude over that period.