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The Atlas-Meseta intracontinental orographic system of Morocco experienced recent, large-scale surface uplift as documented by elevated late Miocene, shallow-water marine deposits exposed in the Middle Atlas Mountains. The Anti-Atlas Mountains do not present any stratigraphic records that document regional vertical movements, however, the presence of a high-standing, erosional surface, and the transient state of the river network, provides insights into the uplift history of the belt and the mechanisms that drove it. Here, we combine geomorphic and stream profiles analyses, celerity of knickpoints and linear inverse landscape modeling with available geological evidence, to decipher the spatial and temporal variations of surface uplift in the Anti-Atlas and the Siroua Massif. Our results highlight the presence of a transient landscape and document a long wave-length topographic swell (similar to 100 x 600 km) with a maximum surface uplift of similar to 1,500 m in the Siroua Massif and similar to 1,100 m in the central Anti-Atlas most likely starting from similar to 14 to 10 Ma. Surface uplift occurred in association with the onset of late Miocene magmatism in the Siroua and Saghro Massif and contractional deformation in the High Atlas. Regional surface uplift was most likely due to deep-seated mechanism, such as asthenospheric upwelling. Additional processes such as magma injection and faulting contributed to the surface uplift of the Siroua Massif. Overall, our approach allows to quantitatively constrain the transient state of the landscape and the contribution of regional surface uplift on mountain building processes.

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

Continental collisional zone may include high-standing plateaus, both internally and externally drained. When endorheic basins are integrated into external drainage networks, the rivers could retain first order information on the capture as well as the interplay between climate and tectonic processes. The Eastern Anatolian Plateau (EAP) of the Arabia-Eurasia collision zone is one of the most representative examples of collisional plateau. It has a mean elevation of ~2000 m, presents three main endorheic basins (Van, Sevan and Urmia lakes), and is mostly drained by three river networks: the Kura-Arax drainage system to the NE, the Ҫoruh to the NW, and the Euphrates-Tigris to the SW. Seismic data indicate the presence of a thinned or totally removed lithospheric mantle beneath the plateau explaining the high heat flow and the late Cenozoic volcanic activity in the area. Despite the great number of studies on the EAP, its uplift history is still debated.In this study we quantitatively investigated the drainage systems (river longitudinal profiles and chi-plots) and the general topographic features (swath profiles, slope, local relief, filtered topography) of the EAP. The results describe a topographic configuration characterized by a high-standing, low-relief plateau centered in the area of Lake Van, but strongly disrupted by tectonic structures with the formation of local topographic highs and lows that include endorheic basins. The fluvial network pattern is strongly disorganized and controlled by active tectonic structures. The irregular longitudinal profiles indicate that rivers are in a transient state of disequilibrium because of regional uplift, capture events or local tectonic activity. The presence of an uppermost fluvial segment characterized by low channel steepness suggests that the plateau interior has not been reached yet by the erosive wave produced by uplift. The chi-plots of the rivers draining the EAP suggest a complex uplift history, evidencing differences between the northern and the southern portions of the plateau in terms of uplift history and drainage system evolution. This uplift pattern is partially confirmed by the stratigraphic record documenting a southward younging transition from a marine to a continental depositional environment. In conclusion, the EAP is a high-standing plateau where the integration of hydrography into it is ruled by regional differential uplift and active tectonic structures.

The interaction between sedimentation/erosion and faulting represents one of the most intriguing topics in landscape and tectonics evolution. Only few studies have been able to document the feedback between faulting and sedimentary loading from field observations. Here, we focus on how sediment loading/unloading influences the dynamics of fault systems in the Fucino basin, in the Central Apennines (Italy). The Fucino basin represents a remarkable case study with respect to the other main extensional basins in the Apennines because of its large dimension, square shape, significant sediment thickness, and its endorheic nature throughout its evolution. We present a detailed structural and geomorphologic analysis of the Fucino basin and its surroundings, investigating the kinematic and geometry of each main fault strand. The slickenlines analysis reveals multiple families of slip-vectors and timing of activity, suggesting a change in extension slip-direction from N240° to N200° during middle Pleistocene. Using a local isostatic model, we estimate that up to the 30% of the vertical geological displacement of the faults, which overall ranges from 0.5 to 2.5km, is related to the sediment loading/unloading. We demonstrate a positive feedback between sedimentation and faulting which may also lead to a reorganization in fault kinematics related to a significant increase in vertical stress. We propose a conceptual model for the permanent endorheic configuration of the Fucino basin, which includes the effect of sediment loading.

High-elevation plateaus that are positioned in between topographic barriers are common orogenic features in the South American continent, formed under a range of evolving environmental conditions. For example, in the central Andes (Bolivia-Argentina), the Puna-Altiplano is arid and endorheic with a poorly developed fluvial system, while in the northern Andes (Colombia) the Chiquinquira and Tunja highlands are characterized by a humid equatorial exorheic fluvial system. In addition to a plateau-like low-relief surface at 2500 m, the landscape of the northern Eastern Cordillera and Santander Massif (northern Colombia) displays a lower elevation (~1500 m) low-relief landscape (Mesas) comprising river captures, windgaps, and a disconnected alluvial fan that collectively record a transient state. This configuration has been achieved through a combination of compressive deformation and sub-crustal processes. The compressive shortening started to occur in the Paleogene and is still active, whereas regional surface uplift related to slab flattening and mantle wedge hydration started in the Late Miocene/Pliocene. To disentangle the crustal vs sub-crustal forcing and to investigate the relative timing of drainage network evolution we combine the analysis of topography, hydrography (river longitudinal profiles, morphometric parameters, drainage divide stability), knickpoint migration (celerity model), paleo-longitudinal profile modeling, satellite images, and field observations. In particular, we show that during the development of the low-relief Mesas landscape the older Chiquinquira highland was a closed drainage and that the lower portion of the Suarez River flowed northward into the Bucaramanga depression forced by the Los Cobardes Anticline topographic barrier. The Suarez River collected waters from the southern Santander Massif and the upper reach of the Chicamocha River, which was draining the Tunja highland. An abandoned windgap deposit on the eastern edge of the Mesa de Barichara suggests that the lower portion of the Chicamocha River was not yet formed. Subsequent to the Chiquinquira highland drainage opening, two main tributaries of the Magdalena River, the Lebrija and Sogamoso, captured the Suarez River in a short temporal sequence. A knickpoint celerity model allows us to date the Lebrija capture of the Bucaramanga depression at ~260–270 ka and the subsequent Sogamoso capture at 190–220 ka. Only during this final stage, the lowermost Chicamocha River section formed and the drainage network developed to its present configuration. Finally, we suggest that the early Cenozoic rift inversion has controlled the drainage network pattern and the late Miocene sub-crustal-induced surface uplift has driven the main fluvial network reorganization.

Continental areas affected by mantle plume dynamics are characterised by extensive high-elevated regions drained by large radial river networks. Despite successive isostatic adjustments and rifting events, several studies demonstrated that the persistence of these drainage systems for tens of millions of years is possible. In these geodynamic contexts rivers are precious sources of knowledge because, propagating the signals of tectonic and climatic changes across landscape, they shape the topography and allow to recognise the first-order imprint imposed by mantle plume. The Horn of Africa, characterised by the coexistence of a continental rift system, a large igneous province (continental flood basalts), and a wide uplifted plateau, is an ideal test site to investigate the interrelations between surface and deep processes. Studies demonstrated the long-term persistence of some river networks draining the region and the strong influence of dome-like uplift on their evolution. However a regional-scale quantitative river network analysis is missing, as well as, a complete evolutionary scenario of the Horn of Africa drainage system. In this study we quantitatively investigated the topographic configuration of the Horn of Africa and analysed the four principal drainage systems (Blue Nile, Tekeze, Omo, Wabe Shebele basins), extracting the river longitudinal profiles and the main topographic and hydrologic parameters. In order to reconstruct the evolution of the region, we elaborated the pre−/syn- and post-flood basalts topographies and calculated the elevation gain and loss with respect to the present configuration. Finally, we delineated a possible future drainage system evolution by analysing the present drainage divides stability. The results allowed to reconstruct the evolutionary scenario of the Horn of Africa river network since Oligocene and to investigate the mutual influence between surface and deep processes in shaping the landscape, providing new constraints to understand the formation and evolution of a drainage system in a context of a topography supported by a mantle plume.

The article presents the results of the first year of work of the national research project on E ̄ra ̄nšahr in Parthian and Sasanian times, carried out by three research teams of Sapienza – University of Rome, University of Bologna and University of Turin (PRIN 2017PR34CS “Eranshahr: uomo, ambiente e società nell’Iran arsacide e sasanide. Testimonianze scritte, cultura materiale e società da Arsace a Yazdegard III. Tre casi studio: Pars, Pahlaw e Khuzestan”). The project was born to investigate the relations between man, po‐ litical power and territory in Iran during the Arsacid and Sasanian periods (III BC ‐ VII AD), a millennium of history set between two political transitions of considerable importance: the first between the dynasty of Seleucids and that of the Arsacids; the second between the Sasanian Empire and the Islamic Caliphate. In this framework, we intend to analyse the elements of continuity and discontinuity that have contributed to shaping the Iranian identity. The research considers two categories of documents, namely written sources and those more closely related to material culture, to study three nodal areas of ancient Iran, each one linked to the specific research interests of one of the three teams: the central‐northern plateau between the historical regions of Ma ̄d and Pahlaw (Sapienza), Pa ̄rs (Bologna) and Khuzestan (Turin). The project embraces deep interdisciplinarity and provides for the involvement of three complementary units operating with different methodological approaches. We, indeed, believe sharing different disciplinary skills in a transversal perspec‐ tive to be essential to adequately address one of the most significant cultural contexts of the ancient world.

The Nile is the longest river on Earth and has persisted for millions of years. It has been suggested that the Nile in its present path is ~6 million years old, whereas others argue that it may have formed much earlier in geological history. Here we present geological evidence and geodynamic model results that suggest that the Nile drainage has been stable for ~30 million years. We suggest that the Nile’s longevity in essentially the same path is sustained by the persistence of a stable topographic gradient, which in turn is controlled by deeper mantle processes. We propose that a large mantle convection cell beneath the Nile region has controlled topography over the last 30 million years, inducing uplift in the Ethiopian–Yemen Dome and subsidence in the Levant Sea and northern Egypt. We conclude that the drainage system of large rivers and their evolution over time can be sustained by a dynamic topographic gradient. The path of the river Nile has been stable for as long as 30 million years, sustained by mantle convection, according to geophysical and geological evidence and geodynamic model simulations.

Despite the high geoheritage value of caves and karsts, northern Ethiopia’s largest cave at Zeyi (13.5586°N, 39.1454°E) in the Dogu’a Tembien district has received little attention so far. We have studied its geological, geomorphic, socio-cultural and historical dimensions in a holistic way. The basal member of the Antalo Limestone, in which the Zeyi cave is located, consists of grainstone and wackestone with subordinate marly interlayers. Over a length of 364 m, the oval-shaped gallery displays stalagmites, stalactites, five columns, dissolution holes (“bell-holes”) following joints, stalagmitic floors and other concretions or speleothems. In the absence of any dating of the cave, we contrasted its elevation above the current local base level with known average incision rates of the northern Ethiopian highlands to reconstruct its age, which was calculated as at least 2 to 4 million years. The palaeo-environmental information that is archived in the Zeyi cave sediment would hence cover the Pleistocene. The graves in the sediment at the bottom of the Zeyi cave further indicate that the place could be an ancient burial site, which gives scope for archaeological research. Zeyi boosts a unique combination of abiotic, biotic and cultural components: the nineteenth c. church under the overhanging cliff; the unique cave; the speleothems, cliffs and gorges; and the cave’s bat colony which has been genetically confirmed to be composed of three syntopically roosting species. Accounting for a good balance between cave research, community-based geotourism, geoconservation and biodiversity conservation, the Zeyi cave has strong credentials to become a top geotouristic site in northern Ethiopia. However, major work needs to be done, including granting access for women and organising community-based geotourism.

The Apennines chain is an active Neogene fold-and-thrust belt resulting from the westward subduction of the Adriatic microplate. Starting from the end of the Early Pleistocene, the chain was affected by an increase in regional uplift. Recent GPS data resolved uplift rates of 1–2 mm/yr for the whole Apennines, whereas, in the Adriatic flank, several studies estimated rates between 0.3 and 0.5 mm/yr over the last 1 Myr. A number of works investigated the evolution of the drainage systems along the Periadriatic margin of the Apennines providing long-term incision rates. Studies from the northern part of this sector reported uplift rates varying from 0.2 to 1.1 mm/yr, whereas only few studies concentrated on the central sector of the Adriatic flank of the Apennines, focusing mainly on the evolution of the lower reach of major rivers. This work aims to quantify the long-term rock uplift and incision rates of the eastern portion of the central Apennines through the analysis of the Tronto River basin. Because of its geologic and geomorphological configurations, this basin is an ideal test site to investigate the influence of tectonics and climate on the recent topographic evolution of the central Apennines. The basin extends, with a roughly WSW-ENE direction, from the inner sector of the chain to the Adriatic coast, crossing several tectonic structures such as the Amatrice extensional basin and the Acquasanta and Montagna dei Fiori anticlines. In particular, in the Acquasanta Terme area, the right flank of the Tronto River valley is characterized by fluvial and travertine deposits organized and exposed in several levels. In this work, we investigated the hydrography (river longitudinal profiles) and topography (swath profile, slope, and local relief) of the Tronto River basin coupling these data with field observations and geochronological analysis on the continental sediments (fluvial deposits and travertines) outcropping in the Acquasanta Terme area. To better characterize the nature of travertines, we performed geochemical characterization of three travertine-forming thermal springs obtaining their physico-chemical parameters, the percentage of dissolved gases, and the isotopes content. Finally, we applied a knickpoint celerity model to chronologically constrain the geomorphological evolution of the whole drainage system. The results show the occurrence of a continuous tectonic uplift (~0.5 mm/yr) across the study area since Middle Pleistocene. The uplift, together with climate fluctuations, drove the incision (~0.6 mm/yr) of the landscape and the delineation of the present drainage network. These data are consistent with previous estimates of uplift and incision rates in adjacent areas and provide new constraints on the Quaternary evolution of the central Apennines. This study highlights how the coupling of field surveys with morphometric and topographic analyses of a drainage system is crucial to understand and quantify the influence of tectonic and climate changes in shaping the landscape.

Large river systems play an important role in Earth dynamics since they exert an influence on geological, geomorphological, and geochemical processes. On the other hand, these landforms occur in a variety of topographic and plate tectonic settings and tend to persist for 107–108 yr, resisting variations in environmental conditions. Both modern and ancient big rivers configurations suggest that the persistence of such features is much longer on passive margins with long-lasting continental tilting and long-term rainfall without interference from continental glaciation, desertification, and volcanism. The literature on the geological evolution of river systems concentrates almost entirely on large-scale river basins. Very little research has been done to understand the evolution of smaller river networks that have a much lower persistence because they are more sensitive to climatic and tectonic changes. In this work we focused on the Wabe Shebele River basin (SE Ethiopia, SW Somalia) that drains the eastern slope of the Horn of Africa. It is a medium-scale drainage system (drainage area of ~105 km2) developed on a long-lived regional slope to the SE inherited from the Early Mesozoic and influenced by tectonic structures relative to a passive continental margin and slightly affected by volcanism. By taking into consideration the present topography (swath profiles, filtered topography, slope, local relief), the river network (river longitudinal profiles, channel gradient), and the ancient landforms present in the region, we demonstrate that the Wabe Shebele River basin, despite its medium scale, is a long-lived landform persisting at least since the Oligocene. The results show that even smaller river systems can have a long-term history in favorable tectonic and topographic conditions.

In convergent systems, tectonics, erosion, and sedimentation control orogenic evolution. The nature of the interaction between these factors is still to be unraveled, because of their complex feedback that goes through different time and spatial scales. Here, we try to bind tectonics, erosion, and sedimentation by running laboratory-scale coupled analog models of landscape evolution, in which both tectonic forcing and surface processes are modeled, trying to unravel the nature of these multiple-interrelated processes. The analog apparatus consists of a rectangular box filled with a water-saturated granular material. The deformation is imposed by the movement of a rigid piston (backstop), while surface processes are triggered by simulated rainfall and runoff. We systematically vary the convergence velocity and the rainfall rate, testing how different boundary conditions affect the balance between tectonics and surface processes and the onset of steady-state configurations. We measure the competition between input fluxes (tectonics) and output fluxes (erosion) of material. The results show how analog models never achieve a steady-state configuration in which tectonic rates are perfectly balanced by erosion rates. Tectonics add more material to the accretionary wedge than is removed by erosion (about 2-5 times more). Still, erosional fluxes seem to reach an equilibrium with the applied tectonic flux. The foreland is always overfilled with sediments, and we argued how the storage of sediments in front of a wedge can strongly divert the orogenic system from the “classical” steady state configuration. This work analyzes which are the main differences between analog and theoretical models and if/how the results coming from analog models can be exportable when interpreting natural landscape morphologies and force balance.

We present a geologic map of the Tekeze River basin that covers an area of ∼69,000 km2 of northern Ethiopia. The map synthesizes new data collected in two campaigns between March, 2012 and January, 2013 and compiled at a scale of 1:500,000 with published geologic surveys. The map focuses on the main geologic and tectonic features relevant to a modern interpretation of the geologic evolution of northern Ethiopia and as such, it represents an important synthesis for environmental and natural resource management.

An outlier consists of an area of younger rocks surrounded by older ones. Its formation is mainly related to the erosion of surrounding rocks which causes the interruption of the original continuity of the rocks. Because of its origin, an outlier is an important witness of the paleogeography of a region and, therefore, essential to understand its topographic and geological evolution. The Mekele Outlier (N Ethiopia) is characterized by poorly incised Mesozoic marine sediments and dolerites (∼2000 m in elevation), surrounded by strongly eroded Precambrian and Paleozoic rocks and Tertiary volcanic deposits in a context of a mantle supported topography. In the past, studies about the Mekele outlier focused mainly in the mere description of the stratigraphic and tectonic settings without taking into account the feedback between surface and deep processes in shaping such peculiar feature. In this study we present the geological and geomorphometric analyses of the Mekele Outlier taking into account the general topographic features (slope map, swath profiles, local relief), the river network and the principal tectonic lineaments of the outlier. The results trace the evolution of the study area as related not only to the mere erosion of the surrounding rocks but to a complex interaction between surface and deep processes where the lithology played a crucial role.

Rock avalanches are among the most hazardous processes on hillslopes because of high velocity, great dimensions, and long run-out distance. For this reason, understanding the dynamics and factors of rock avalanches and their role in hillslope evolution is crucial. Studies evidenced that occurrence and evolution of these phenomena are influenced by lithological, structural, and climatic factors. Statistical analysis on natural cases demonstrated correlations between slope geometry and rock avalanche volume. Most of the studies referred to experimental tests which represent powerful tools to understand these landslides. Many models focused on the mechanism leading to high velocity and long run-out, but few studies discuss the role of rock avalanches in the evolution of a bedrock hillslope. The influence of slope geometry and physical properties of the substratum on the dynamics of rock avalanches is poorly constrained. We present results from analog models of a hillslope evolving by base level lowering. We tested several slope widths and two analog materials. The experimental apparatus allowed for checking the mass of mobilized material at each step and for taking a 3D scan of the whole surface. Our results, coupled with a statistical analysis, indicated that hillslope evolution is influenced by the material internal friction and by the friction with box walls (i.e., valley walls) when the slope is narrow. Widening the slope, the influence of lateral friction disappears, confirming observations in other models and nature. These results represent a new contribution to understand the dynamics of rock avalanches on bedrock hillslopes.

The Dogu’a Tembien Massif is located on the western margin of the Mekelle Outlier, a nearly circular hilly area (8000 km2) with an average elevation of ~2000 m (Fig. 2.1) and elevations ranging between 1200 and 2850 m (Fig. 2.1a). The landscape, although deeply incised by rivers, is characterized by four planation surfaces (Palaeozoic, Triassic, Cretaceous, and Tertiary in age) that can be observed in the area northwest of Mekelle. They represent wide surfaces formed during long periods of tectonic quiescence when longstanding erosion shaped a gently rolling landscape down to almost sea level (see chapter 11). This chapter presents the regional geography of Dogu’a Tembien. Most geological formations, as well as planations and later dissection of the massif are detailed in the next chapters.