ICG2022-9

New geomorphological analyses of a wide coastal sector (ca. 1500 km²) between northern Calabria and Puglia (Lucanian segment), including a well exposed area of marine terraces along the Ionian coast of southern Italy, have been carried out. This belt represents a key area for investigating the middle-late Quaternary morphological and tectonic evolution of the orogenic system of southern Italy. The main goal of our research was the construction of a new, detailed and complete map of the entire sequence of marine terraces and associated paleoshorelines along the whole coastal sector. This was achieved following a systematic analysis of air‐photos and satellite images, integrated by field work and survey devoted to checking all the morphological features. Data were interpreted by uniform methods of geomorphological analysis in order to obtain an accurate reconstruction of the lateral continuity of the terraces and, therefore, to solve the problems of geometric and numerical fit between the terraces staircases from different sectors of the coastal belt separated by major rivers. A critical review of the literature related to geochronological data from the study area, integrated with a morphogenetic model based on the interaction between tectonic uplift and eustatic sea-level changes, allowed demonstrating that the different terraces are correlated to many highstand peaks, dating the highest/oldest terrace to mid-Pleistocene times. Such an approach allowed us to revise the wide data set related to the estimates of uplift rates based on the merely altitudinal criterion. Another relevant outcome of our study implies that the most external sectors of the orogenic chain (i.e. the southern Apennines), and likely the whole chain‐foredeep-foreland system, probably remained under a prevailingly compressional tectonic regime during the entire Quaternary period, with consequences for the seismic hazard of the region.

How to cite: Corrado, G., Di Leo, P., Gioia, D., and Schiattarella, M.: The marine terrace staircase of the Metaponto coastal belt, southern Italy: from geomorphological mapping to uplift rate estimates revised, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-340, https://doi.org/10.5194/icg2022-340, 2022.

Offshore islands may furnish valuable information regarding deformation rates, their controlling mechanisms, and the dynamics of the upper crust in offshore areas along subduction zones, which otherwise would be difficult to quantify by direct observations. Here we study active deformation and faulting at glacial-cycle time scales in the Kythera Island, located in the southwestern part of the Hellenic subduction zone, between Crete and the Peloponnesus. The Kythera Island exposes an outstanding sequence of more than twelve levels of marine terraces that depict the active uplift of the island. These terraces are offset by several NNW-SSE and NNE-SSW-oriented active faults. We use high-resolution topography combined with morphometric analysis to map the marine terraces and to estimate the heave and throw rates of the main faults on the island. We divide the marine terrace sequence into two groups, the higher marine terraces (260 – 480 masl) comprising composite rasa surfaces, and the lower terraces (20 – 220 masl) characterized by staircase morphologies. We focus on the two main faults of the island, defined as F₁ and F₂, which display right- and left-lateral and dip-slip displacements, offsetting the marine terrace risers and treads. We link the activity of these faults with the occurrence of intermediate-depth and strong magnitude earthquakes such as the Mw 6.6 and 6.7 that occurred in the area of Kythera in 1903 and 2006, respectively.  Further dating of marine terrace surfaces and structural analysis will be carried out in the next months in order to correlate the marine terraces with Marine Isotope Stages and to estimate heave and throw rates of the faults. Our work emphasizes the importance of carrying observations in islands to elucidate the deformation rates in offshore areas of subduction zones.

How to cite: Tsanakas, K., Jara-Muñoz, J., Karymbalis, E., Yildirim, C., Pedoja, K., Batzakis, D.-V., and Griva, D.: Quantifying active faulting using marine terraces, Kythera Island, Greece, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-369, https://doi.org/10.5194/icg2022-369, 2022.

The Neogene to Quaternary southern Apennines mountain belt is flanked to the SW by the Tyrrhenian Sea back-arc basin, which was formed since late Miocene times. Extensional tectonics related to back-arc basin formation affected the Tyrrhenian margin of the southern Apennines since the Quaternary with formation of a series of horst and graben structures. Huge amounts of existing surface, subsurface and offshore data indicate that subsidence on the order of thousands of metres affected the grabens, and remarkable flights of marine terraces are indicative of Quaternary uplift of the horst blocks. The highest and older marine terraces, Early Pleistocene in age, occur up to several hundreds of metres above the sea level.

A huge number of former studies have provided fundamental data on both the outcropping (raised) and buried paleoshorelines and littoral deposits, the chronological framework for the identified relative sea level fluctuations mostly rests on local-scale relative chronology reconstructions constrained by dating that are still quite rare and sparse.

Detail-scale geomorphological-geological mapping, integrated with Quaternary stratigraphy, aimed at the recognition, characterisation and dating of raised marine terraces and paleoshorelines (tidal notches, platform inner edges) has been carried out in several key areas of the southern Apennines Tyrrhenian Sea margin, from Campania, in the North, to northern Calabria, in the South. The field surveys have been carried out both in rocky coasts (where continental deposits cover and sometimes hide the paleoshorelines) and in the two main alluvial-coastal basins, namely the Campania and Sele River plains. The new geochronological data constrain the ages of several late Middle Pleistocene to Late Pleistocene sea level markers, allowing a better definition of the vertical motions in each study area. Overall, the time-space distribution of the vertical motions on the regional scale is better reconstructed, along with the framework of the Quaternary surface uplift of the southwestern slope of the southern Apennines mountain belt.

How to cite: Cerrone, C., Ascione, A., Robustelli, G., Soligo, M., and Tuccimei, P.: Marine terraces in the Tyrrhenian Sea margin of the Southern Apennines (Italy): new constraints on differential vertical motions from dated paleoshorelines, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-540, https://doi.org/10.5194/icg2022-540, 2022.

The relative sea-level (RSL) change is a sum of effects of processes acting on local, regional and global scales. By far the most variable component of RSL change relates to local, non-linear scale processes, that is to active tectonics. The studied islands and islets, Lopud, Koločep and Grebeni are part of Dubrovnik archipelago, situated near the external front of the Dinarides where seismicity attains one of the highest levels in Croatia. The focal mechanisms in the area show that reverse and transpressive faulting prevails.

Studying the RSL markers: algal rims, tidal notches and Lithophaga lithophaga borehole upper limits, we identified one elevated palaeoshoreline at Lopud island (today 25-30 cm above the mean sea-level (MSL)) and two elevated palaeoshorelines at Koločep island and Grebeni islets (60-90 cm and 25-40 cm above MSL). The high-resolution geochronology built on radiocarbon dating of algal rims (77 sea-level index points) enabled the distinction of coseismic uplift events from subsidence periods during the last 3300 years. As a result, we provide new, field-based reconstruction of palaeoearthquakes, describe spatial patterns of differential uplift and distinguish the main drivers of RSL change.

Two major seismically triggered uplift events with displacements between 40 and 80 ± 15 cm per event have been differentiated along investigated sectors of the coast related to the Pelješac-Dubrovnik fault zone pointing to repeated earthquakes of magnitudes exceeding Mw = 6.5. The earlier, older events, caused larger displacements (60-80 cm) related to 4th to 6th century AD and 750-1100 AD earthquakes, while the later, younger events, revealed on average lower displacements (40-55 cm) corresponding to the 1520 AD quake and the 1667 Dubrovnik earthquake. The cumulative offsets increase from around 0.57 ± 0.15 m at Lopud to 1.00-1.25 ± 0.15 m at Koločep and Grebeni.

Interseismic periods allow further insight into regional and global driving mechanisms of RSL change. The distinction of local coseismic displacements of RSL history together with the previously obtained regional glacio- and hydro-isostatic adjustment estimates (between 0.30 and 0.34 mm/yr) allow us to approach the global contribution, which seems to be minimal between ~0 and 1800 cal AD as RSL changed at rates of 0.3 to 0.4 mm/yr. The increased rates of RSL change occurred prior to 0 cal AD, with rates of around 0.7 mm/yr, and go up to 1.4 mm/yr after 1800 cal AD.

Overall, here we demonstrate the importance of Lithophyllum rims in the studies of RSL change as they make creation of high-resolution geochronology possible. Moreover, this new approach refers to algal rims as a possible tool for constraining palaeoseismic events, allowing to supplement the database of instrumental records and historical observations through field-based evidence. This research was supported by Croatian Science Foundation project HRZZ-IP-2019-04-9445 – Relative sea-level change and climate change along the eastern Adriatic coast – SEALeveL.

How to cite: Faivre, S., Bakran-Petricioli, T., Herak, M., Barešić, J., Horvatić, D., and Borković, D.: Lithophyllum rims as markers of palaeoseismic events and relative sea-level change in the Dubrovnik archipelago, Southern Adriatic, Croatia, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-36, https://doi.org/10.5194/icg2022-36, 2022.

Cyprus is located right on the plate boundary where the African Plate subducts beneath the Anatolian Microplate. Although subduction zones are earthquake-prone areas, the seismicity of the Cyprus and adjacent areas are not very active during the instrumental period. Nevertheless, archaeological and historical data indicate casualties and destructions within the island because of strong tremors and tsunamigenic waves. None of these data gives information about the source faults of these earthquakes. Are they far-field earthquakes (e.g., AD 365 Crete) or near-field earthquakes that occurred nearshore of the island? We focused on the island’s coast and mapped geomorphological, sedimentological, biological, and archaeological strain markers to answer these questions. Our geomorphological observations reveal the presence of at least three major Holocene abrasion platform levels uplifted coseismically. The presence of biological markers such as reef rims provides a dateable material to quantify these events. We also observed archaeological fish tanks as evidence of coseismic uplift of the shoreline during the historical periods. Radiocarbon ¹⁴C dating results indicate a temporal clustering of earthquakes within the 1300-1700 yr BP, 2000-2200 yr BP, and 4500 yr BP, which indicate overlapping of 4^th and 6th-century historical earthquakes and also older earthquakes beyond the historical records.

How to cite: Yildirim, C., Melnick, D., Tüysüz, O., Altınbaş, C. D., Jara-Munoz, J., Tsanakas, K., Özcan, O., and Strecker, M.: Earthquakes that Uplifted Cyprus in the last 4 ka, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-417, https://doi.org/10.5194/icg2022-417, 2022.

This work documents for the first time the prehistoric, but morphologically pristine, Emad Deh rock avalanche, located in the Fars Arc of the Zagros Mountains. The Zagros orogen is one of the most seismically active regions in the world. However, large earthquakes are very rarely accompanied by surface ruptures, restricting the possibility of integrating paleoseismic data in seismic hazard analyses. This limitation could be partially overcome by identifying and dating secondary paleoseismic evidence such as coseismic landslides. The source of the Emad Deh rock avalanche is located on a dip slope at the northern limb of the Gavbast anticlinal ridge. The slope, with a local relief of around 800 m, is essentially a hogback with a thick caprock of the competent Asmari Limestone, dipping around 35 degrees and underlain by marls with interbedded limestones of the Pabdeh Formation. The collapse of a bedrock slab around 2x2 km and its disintegration, resulted in the highly mobile Emad Deh rock avalanche, which accumulated on the unconfined piedmont an unstratified, unsorted and highly angular bouldery gravel deposit with an estimated minimum volume of around 220 million m³. The rock avalanche has a maximal height drop (H) of 914 m, a runout measured from the headscarp crown of 9280 m, and a H/L mobility index of 0.09. The cohesionless flow of fragmented rock formed a spatulate-shaped lobe around 32 km² in area with well-defined lateral ridges in the proximal sector, expanding over an arc of 40 degrees and reaching a width of 6.1 km. The distal sector of the lobe displays polygonal hummocks that grade into progressively smaller, and locally radially aligned, conical hummocks. In the terminal sector, the rock avalanche was emplaced on soft floodplain alluvium, which displays folding with vergence consistent with the impacting flow direction. Two OSL ages in correct stratigraphic order obtained from the deformed alluvium indicate an age of ca. 5.5 ka for the Emad Deh rock avalanche, attributable to a major paleoearthquake. Subsequently, four additional planar failures occurred in the rock avalanche scar, mainly affecting marls and limestones of the Paddeh Fmormation, and resulting in more cohesive flows. The deposits of these later landslides, with volumes ranging between 10 and 45 million m³, are confined by the lateral ridges of the rock avalanche and its scar. Cartographic relationships allow inferring their relative chronology.

How to cite: Gutiérrez, F., Zarei, M., Deirnik, H., Rahimi, M., and Medialdea, A.: Geomorphology and geochronology of the coseismic? Emad Deh rock avalanche of the Zagros MountainsGeomorphology and geochronology of the coseismic? Emad Deh rock avalanche of the Zagros Mountains, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-234, https://doi.org/10.5194/icg2022-234, 2022.

Studying the relationship between geological conditions and the geomorphology of a landscape has always been in the focus of geomorphology research. The relationship between structural and morphological elements can be analysed on the basis of a morphotectonic approach in which the role of rock strength is clear in slope conditions and thus in the morphology of an area. The strength of natural rock masses, however, cannot be modelled simply by the laboratory measurements of rock strength. The complex approach of rock mass strength is reflected in the development of various rock mass rating methods.

The authors evaluate the strength of natural rock masses in the Bükk Mountains in Northern Hungary based on the rock mass rating of more than a hundred outcrops scattered across the mountains. Some widespread rock mass rating methods are compared and the rock mass strength values of similar and also of different rock types are analysed. The results reveal that rock type has smaller influence on the strength of rock masses than parting conditions. Therefore, the role of parting surfaces needs to be analysed in detail, especially in areas with strong deformation features. On the edge of tectonic blocks where the deformation of rock masses is strongest, sinigficant fault planes with slickensides, folded structures and thrusts with shear zones compose the dense parting surfaces with so strong compression that massive limestone rock masses have smaller rock mass strength values than porous but much less deformed rhyolitic tuff rock masses.

Based on the results, the role of rock mass strength is assessed in the development and orientation of landforms in certain study areas in the mountains. Moreover, the relationship between rock mass strength and valley density is also studied. Finally, we take a look at the relationship between rock mass strength and the dominant deformation elements of the rocks of the mountains to see what tectonic geomorphological implications can be found.

Based on the rock mass rating methods, some recommendations can be given in relation to slope stability in terms of construction geological applications.

How to cite: McIntosh, R. W. and Seyed, J. A. H.: The role of rock mass strength in landscape development based on the rating of natural rock masses in the Bükk Mts., Hungary, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-670, https://doi.org/10.5194/icg2022-670, 2022.

In intracratonic South America, the origin of neotectonic activity and its impact on large Amazonian rivers have been of continuous research interest, but the available evidence has been only for extensional structures. This investigation focuses on a megascale (~60,000 km²) domal relief from central Amazonia (the Juruá dome). The main goal was to verify the relationship of this anomalous relief with a growing fold and determine the origin of the stress field within the context of Andean uplift along with the westward movement of the South American plate. The approach applied here is unprecedented for the Amazon lowlands. This is because it combines evidence of tectonic adjustments of river systems using morphostructural and morphometric analyses from remote sensing imagery, integrated with subsurface data consisting of gravity and magnetic maps, seismic reflection, and well logs. The Juruá dome consists of a broad, rounded, and smooth, convex relief, with altitudes generally not exceeding 110 m developed into Pleistocene-Holocene deposits. The drainage over the dome is arranged concentrically into a broad annular pattern with localized anomalous segments in the Solimões River and various Amazonian tributaries. The results revealed that the Juruá dome evidence the growth of a broad anticline. Non-linear slightly convex χ-profiles of many rivers that cross or contour the dome evidence transient rivers, consistent with a development under growth fold. The fold modified the course of several rivers within the domal relief area, including the Juruá River, which is entrenched along NE-striking faults that released the stress along the fold axis. NE- and NW-striking normal and reverse faults with flower structure geometries are abundant in subsurface and suggest deformation from strike-slip tectonics. Gravity and magnetic data revealed that the fold and many of its associated faults are deep-rooted into basement rocks. The geomorphological and structural data are collectively compatible with a long-term NW-trending maximum horizontal compressive stress-field that is driving basin inversion. This neotectonic activity can be linked to far-field stresses from the pushes from the Andean orogeny and the movement of the South American plate against the North Andean and Nazca plates. Thus, this study can expand our knowledge on the impact of far-field stresses in intracratonic settings transmitted from collisional and constructional tectonic plates. Detecting active folded reliefs in central Amazonia is a new approach that can help characterize the extension and source of compressive far-field stresses in intracratonic northern South America.

How to cite: Rossetti, D., Vasconcelos, D. L., Bezerra, F. H. R., Valeriano, M. M., Alves, F. C., and Molina, E. C.: Late Quaternary large-scale folds in intracratonic central Amazonia evidenced from tectonic geomorphology, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-308, https://doi.org/10.5194/icg2022-308, 2022.

The tectonic structure of Sardinia is linked to the geodynamic evolution of the western Mediterranean during the Alpine phase. In particular, the eastern continental margin is the result of the opening of the Tyrrhenian basin which is still evolving. The Pliocenic and Quaternary distensive phase lead an uplift in Sardinia whose effects are manifested in the geomorphological setting. Morphotectonic analysis were used to characterize paleo and active geomorphological processes in Ogliastra area. Palaeo-erosive surfaces, volcanic mesas, Steep slopes, involute hydrographic basins, widespread landslides shaped the inland, while the submerged continental margin in affected by engraved active canyons and landslide.

To analyze the continental area large scale geological, geomorphological, geostructural, morphostratigraphic surveys integrated by PS-INSAR, Uncrewed aerial vehicle, LiDAR Remote sensing data were used.

Seismic sparker, sub-bottom profiler chirp, multibeam, side scan sonar made it possible to analyze the evolution of the submerged area.

In particular, fluvial captures, river terraces, engraved valleys, waterfalls and heterogeneous water drainage characterize the streams setting. Coastal Quaternary volcanism present relief inversion plateaus. The slope area affected by different kind of landslide conferring at the Ogliastra the main geomorphogical hazard of Sardinia. Widespread Deep seated gravitational slope deformation both active and quiescent are preset in different structural and tectonic setting. Paleo erosive surface since the Carboniferous are found located at different elevation.

The eastern continental margin of Sardinia is made up of a north-south oriented host and grabben system linked to the open Tyrrhenian basin. The continental shelf is very narrow and indented by several narrows and straight submarine canyons. Head retreat processes of the canyons are evident, that have notably affected the continental shelf. The continental slope is made up of intraslope basins and seamounts oriented N-S whose slopes are affected by active and paleo landslides, slumps and erosional incisions.

Multi-source and multi-scale data showed the role of the uplift rebound in the landscape evolution.

High resolution morphotectonic map were reconstructed, highlighted and integrated all different morphologies and process.

How to cite: Demurtas, V., Orrù, P. E., and Deiana, G.: Morphotectonic evolution of eastern Sardinia: relations between inland and the continental margin, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-526, https://doi.org/10.5194/icg2022-526, 2022.

The Acıgöl Graben is located in an extensional province of western Turkey, related to combining effects of the southwestward retreat of the Hellenic trench and the westward displacement of the Anatolia Plate. This is a 50 km long and 10 km wide neotectonic depression with a NW-SE orientation that veers into an E-W trend in its southern part. The basin has a late Miocene to Quaternary fill, and according to borehole data Quaternary sediments exceed 600 m. The Acıgöl and Maymundağı Quaternary faults, respectively, control the SE and NW margins of this internally drained basin, which hosts a playa-lake. The higher elevation of the SE mountain front and the proximity of the lake to this margin suggests some asymmetry in the graben structure. This study analyses the graben-bounding faults by means of detailed geomorphological mapping, and demonstrates their late Quaternary activity by geomorphic evince and Optically Stimulated Luminiscence (OSL) dating. The Acıgöl Fault on the SW margin juxtaposes Mesozoic carbonate rocks against Quaternary deposits along the linear mountain front-piedmont junction. The uplifted range, with a local relief of around 1 km, shows geomorphic evidence of deep-seated gravitational slope deformation (DSGSD), such as ridge-top depressions, uphill-facing scarps, internally drained troughs and bulged toes. The SW margin on its southern sector displays E-W intra-basin faults that offset and tilt recent basin-fill deposits, producing backtilting on geomorphic surfaces. These deformations control the anomalous orientation of some drainages that flow towards the basin margin. OSL ages provide a maximum age of 24 ka for the youngest displacement event on these faults. On the NW margin of the graben, the Maymundağı Fault, with a NW-SE to E-W orientation, is expressed as a linear mountain front with triangular facets up to 700 m high. This fault juxtaposes Oligocene conglomerates against Quaternary alluvial fan deposits. In the southern section where the basin attains an E-W trend, the fault displays two parallel fault strands. The northern fault strand is the master basin bounding fault located at the toe of the mountain front, whereas the southern one is an intra-basin fault expressed as a scarp that offsest alluvial fan surfaces and deposits. Here we differentiate two generations of alluvial fans: (1) oversteepened and dissected old fan surfaces restricted to the footwall block; and (2) active fans in the downthrown block with their apex at intersections points associated with the fault scarp. Numerical ages indicate fault activity younger than 3 ka.

How to cite: Tunçel Gökkaya, E., Çiçek, İ., and Gutiérrez, F.: Tectonic geomorphology of the Acıgöl Graben, western Turkey, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-263, https://doi.org/10.5194/icg2022-263, 2022.

The largest expression of neotectonics in the State of Mato Grosso do Sul is documented in the Pantanal Sedimentary Basin, considered a N-S tectonic trench, with 400 km in length, 250 km in width and a sedimentary thickness of > 400 m. The Pantanal Basin is located in the west of the Mato Grosso do Sul state, occupying an area of 135,000 km². The Pantanal Plain is surrounded by the Maracaju-Campo Grande and Taquari-Itiquira plateaus to the east, Guimarães and Parecis to the north, Urucum-Amolar to the west and Bodoquena to the south. The region is surrounded by plateaus in rocks that range from the Precambrian to the Cenozoic. Historically, the Pantanal Basin is considered one of the seismic regions of Brazil. Intraplate earthquakes mainly result from ruptures along zones of preexisting weaknesses, located close to structural inhomogeneities, which concentrate efforts that, added to regional efforts, are capable of generating earthquakes. The main structural features identified are expressed by joints, faults and fault zones. Two main sets of fault types were recognized: normal and transient. The normal faults are those related with the NE-SW opening of the basin, while the transcurrent faults are younger and characterized by an E-W direction. The direction of the binary E-W and dextral movement enable the development of NW-SE discontinuities. The drainage network and the structure of the landforms are strongly controlled by these structural discontinuities, associated with the collapse of blocks. This allows the development of areas with greater subsidence and accommodation space for Holocene sediments in the basin, such as the so-called “Brejão do Negro”, which proved to be a frequently flooded area, marked by a hidden fluvial lake due to a floating mat of macrophytes. The Rio Negro lineament is an important seismic-tectonic feature in the southeastern portion of the Pantanal Basin, functioning as an E-W shear zone, with current neotectonic movement, forming a pull-apart rhombohedral structure. The earthquakes in the Pantanal Basin present values between 0.6 to 5.4 mb. In the brittle shear region comprised by the Negro lineament (area comprised by the Brejão do Negro), the magnitudes are higher, usually between 3.0 and 4.0 mb. Recent earthquakes recorded in this basin are the result of uniform E-W compression stresses. These lineaments impose tectonic landforms, being indicated by subsidence, escarpment, fluvial avulsions and captures, elbows, rectilinear lake edges, among others, associated with evidences neotectonic activity in the Pantanal Basin. From surveys focused on the identification of structural discontinuities and seismological activity, two tectonic events were identified for the area: the first being distensive, associated with the opening of the basin, and the second of transcurrent character.

How to cite: Facincani, E., Assumpção, M., Cunha, P., and Tadeu, E.: Neotectonics and Seismicity in the southeast edge of the Pantanal Basin (Mato Grosso do Sul, Brazil), 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-296, https://doi.org/10.5194/icg2022-296, 2022.

The geomorphometric analysis of mountain fronts, drainage networks and catchments in tectonically active areas can provide valuable information about the spatial distribution of relative tectonic activity. The aim of this study is to investigate the contribution of neotectonics to the development of the fluvial landscape of the broader Trichonis Lake area (located in western continental Greece) through quantitative geomorphological analysis. The Trichonis Lake graben is a is a late Plio-Quaternary extensional basin, which cuts across the early Tertiary NW-SE fold and thrust structures of the Pindos Mountain belt. It strikes WNW–ESE for a distance of 32 km and has a width of 10 km. The graben at the north and south flanks of the lake is bounded by E-W and NW-SE trending faults. Recent seismic activity (a shallow earthquake sequence in 1975 and a 2007 earthquake swarm) showed the existence of a NNW-SSE normal fault that dips to the NE and bounds the SE shore of the lake. The studied catchments have developed on the hanging walls of these active normal faults. To evaluate the relative tectonic activity in the study area, various morphometric indices including stream length-gradient index, drainage basin asymmetry factor, hypsometric integral, valley floor width-valley height ratio, drainage basin shape, drainage basin slope, relief ratio and Melton's ruggedness number were measured for 35 catchments. In addition, mountain-front sinuosity index has been estimated for 20 mountain fronts around the lake. For the measurement of the geomorphometric variables a digital elevation model (with 5 m cell size), derived from topographic maps at 1:5000 scale (with 4 m contour lines), was used. The catchments of the study area were classified into three classes based on the morphometric variables and a series of maps showing their spatial distribution were produced by applying GIS techniques. The combination of these morphometric variables yielded two new indices of relative tectonic activity (named IRTA: Index of Relative Tectonic Activity and IAT: Index of Active Tectonics). Based on the values of IRTA and IAT, the area was classified into three classes of relative tectonic activity (low, medium, and high). To evaluate the landscape around Lake Trichonis in terms of neotectonic activity, we identified clusters of drainage networks and catchments according to their geomorphic characteristics (expressed by the geomorphometric indices) using self-organizing map, which is a type of unsupervised artificial neural network (ANN). The analysis showed that the development of the landscape of the central part of the northern flanks of the graben has been highly influenced by the tectonic uplift since these catchments are characterized by high IRTA and IAT values which correspond to high relative tectonic activity. The study of these fault-generated mountain fronts showed that although both graben flanks have low sinuosity index values, the central segment of the north flank of the graben has slightly lower values which are indicative of active tectonics.

How to cite: Karymbalis, E., Valkanou, K., Fubelli, G., Ferentinou, M., Tsanakas, K., and Giles, P.: Assessment of relative tectonic activity in the Trichonis Lake graben (Western Greece) a combined approach using geomorphometry and Self Organising Maps, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-368, https://doi.org/10.5194/icg2022-368, 2022.

The growth of a mountain chain results from a complex interplay between endogenous and exogenous processes. The former depends on the geodynamic setting and cause the uplift of the orogenic wedge whereas the latter tend to erode the uplifted topography. Surface uplift may act at uneven temporal and spatial scale and reconstructing its distribution through space and time may provide fundamental data to unravel either the future tendency of geomorphic processes (e.g., increased erosion in uplifted areas) or to identify areas affected by active tectonics. In this study, we adopted a morphotectonic approach to unravel the spatial distribution of surface uplift in active orogens, such as the southern Apennines of Italy. Features of the topography (e.g., maximum, mean and minimum elevation maps, relief maps and swath profile) and the river network (e.g., river long profile and chi-long profile, Ksn index, chi index map) have been derived through ArcGis and Matlab softwares. The combined analysis of all indexes allows recognising a locus of enhanced surface uplift that moves from NE (the Bradanic foredeep) to the SW (the outer sector of the orogenic wedge). Surface uplift do not extend towards the inner sector of the orogenic wedge and its spatial distribution roughly follow the main divide. Furthermore, a natural tendency of the main divide to shift towards the NE has been also identified, that is consistent with the uneven spatial distribution of vertical motions. To quantify differences in surface uplift between the foredeep-outer chain and the inner chain, we analysed published data about MIS5 paleoshorelines. These data also confirmed the uneven distribution of surface uplift at the orogen scale, thus confirming that the adopted morphotectonic approach may be considered a powerful tool to constrain the spatial distribution of vertical motions.

How to cite: Valente, E., Cerrone, C., and Ascione, A.: Detecting differential surface uplift at the orogen scale by topography and river network features: the Southern Apennines case study (Italy), 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-416, https://doi.org/10.5194/icg2022-416, 2022.

Along the Adriatic piedmont zone of central-northern Apennines of Italy, the combination of tectonic uplift with Quaternary climate changes caused the alternating phases of fluvial incision and deposition that eventually produced at least four levels of fluvial terraces. Although the fluvial terraces of this sector of the Apennines have been object of many studies since the first half of the twentieth century, their chronology is still object of debate. Consequently, their use as geomorphic markers of landscape evolution can be challenging. The scarcity of geochronological constraints, especially for the older terraced deposits, in addition to the extreme spatial variability of the terrace geomorphological characteristics along adjacent valleys and within different sectors of the same valley, are the main limitations to the utility of fluvial terraces as geomorphic markers of landscape evolution in this sector of the Apennines. This research presents new geomorphological data for the different terrace generations exposed along the southern Marche Apennines between the middle Pleistocene to the late Pleistocene-Holocene, using remote sensing techniques and field investigation, as well as geochronological data from Optically Stimulated Luminescence (OSL) analysis. The fluvial terrace staircase along the Tesino River valley has been selected for the excellent exposure of the different terrace generations along the valley sides, the good accessibility for sampling, and the geomorphological characteristics of the river valley that can be representative of the ones draining the central-northern Adriatic piedmont zone. Findings from this research are useful for enhancing the knowledge on the evolution of the central-northern portion of the Apennines, providing new constraints for unravelling the contributions of tectonics and climate on the late Quaternary evolution of river valleys in the mid-latitudes zone of the Northern hemisphere.

How to cite: Troiani, F., Delchiaro, M., Gribenski, N., Della Seta, M., Iacobucci, G., Piacentini, D., and Zocchi, M.: Geomorphology and geochronology of the Quaternary fluvial terraces of the Tesino River: new constraints to the landscape evolution in the piedmont area of central-northern Apennines of Italy, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-57, https://doi.org/10.5194/icg2022-57, 2022.

Τhis study aims to investigate to what extent the drainage systems of the northern part of Evia Island, in Central Greece, reflect the contemporary tectonic regime of the area. The effects of tectonic activity have been detected and described by performing a landscape morphological analysis of the drainage systems, followed by a field survey for validating the results. The Relative Declivity Extension (RDE) index, which is based on the Stream Length (SL) gradient index, was calculated along the channels of 189 drainage basins of the study area, using the Knickpoint Finder tool integrated into ArcGIS desktop. The Hack RDE index is defined by the ratio of the RDEs index (which refers to a stretch) and the RDEt index (which refers to the total length of a river) was applied, and its calculation identifies the knickpoints based on anomaly values detection along the longitudinal profiles of the rivers. Furthermore, knickpoint analysis was carried out along the channels of the drainage networks of the northern part of the Evia Island and the corresponding anomaly maps were designed. A total of 2,486 knickpoints were identified and the greatest anomalies (139 points), named first-order anomalies (RDE>10), seem to correspond to a recently shaped or rejuvenated landscape, indicative of intense neotectonic activity. In some cases, the spatial distribution of knickpoints delineates a NW-SE trending yielding the structural control of the study area. The comparison of the results with the lithological map of the area showed that about 30% of the knickpoints are lithologically controlled. The identification of zones of neotectonic activity and consequently the existence of active faults is highly correlated with the distribution of knickpoints and their core density, the drainage density, the drainage asymmetries, and other morphometric indices such as the hypsometric integral, along with the earthquake epicentres, and the morpho-lineament density. The overall analysis showed a positive correlation of the concentration of the derived knickpoints with both active structures and tectonic activity rates. The results were consistent with field observations, which were mainly focused on waterfall landforms. Our study proves that the landscape evolution of the northern part of the Evia Island is considerably affected by the recent activity of normal fault zones, whereas the drainage systems react to the changes of base-level providing insights on active tectonics.

How to cite: Valkanou, K., Karymbalis, E., Vassilakis, E., Soldati, M., Papanastassiou, D., and Gaki-Papanastassiou, K.: Knickpoint extraction for the evaluation of active tectonics: The case of Evia Ιsland, Greece, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-370, https://doi.org/10.5194/icg2022-370, 2022.

A morphometric approach, based on the investigation of the topography and river network features of two hydrographic basins, Utcubamba and Chiriaco, was applied to determine the relationship between the irregular distribution of vertical motions (e.g., surface uplift) and the genesis of supergene Zn deposits located in the Bongará district, in the north-eastern sector of the Peruvian Andes. In the area three mixed supergene-hypogene ore deposits have been recognized: Mina Grande, Cristal and Florida Canyon. The Florida Canyon deposit falls within the Eastern Cordillera, in the Utcubamba Basin, and represents one of the most important Zn-Pb MVT deposits hosted in the carbonate and former evaporite-bearing rocks of the Pucarà Group. The mineralization consists mainly of sulfides and only one-third of the resource is nonsulfides and is hosted in Triassic rocks. The Mina Grande and Cristal deposits fall within the western margin of the Subandean Fold-and-Thrust Belt, in the Chiriaco Basin, and consist mainly of nonsulfide ores with less sulfides hosted in more recent Jurassic rocks. The MVT sulfide mineralizations formed at the same time (70 – 80 Ma) at two different depths of 2,500 - 3,000 m b.s.l. for Florida Canyon and 1,5000 - 2,000 m b.s.l. for Mina Grande - Cristal and currently outcrop approximately at the same altitude of around 2,700 m a.s.l. Since the late Oligocene, when Andean deformation migrated eastward from the Western Cordillera to the present Sub-Andean zone, the rocks of the Pucará Group were repeatedly uplifted and eroded allowing the exhumation of primary sulfide bodies and the formation of the supergene deposits.

The research has been carried out through the evaluation of the parameters such as elevation, local relief, swath profile, river longitudinal profiles, slope/area analysis to derive the normalized channel steepness index (ksn) and transformed river profiles (χ-long profiles). The spatial distribution of such indexes allowed to derive some consideration about the spatial distribution of vertical motions (e.g., surface uplift). Furthermore, the sharp increase in maximum, mean and minimum elevation moving from the Utcubamba Basin to the Chiriaco Basin, coupled with a jump in the mean Ksn values, suggest that the Chiriaco Basin has experienced either more recent surface uplift or surface uplift at rates higher than the Utcubamba Basin. This trend seems to be confirmed by the uneven erosion that the Florida Canyon and the Mina Grande – Cristal deposits have experienced. In fact, the Utcubamba Basin has been subjected to an uplift protracted in the time, resulting in a rugged local relief and lowering the mean and minimum elevations, which would have removed the Jurassic succession and exposed at the weathering the Triassic-hosted Florida Canyon. In the Chiriaco Basin, the higher surface uplift in terms of time and/or rate has exposed at the weathering the Jurassic-hosted Mina Grande – Cristal deposits allowing the almost complete alteration of primary sulphides and the development of non-sulphide mineralization.

How to cite: Valente, E., Sorrentino, A., and Mondillo, N.: Deciphering the spatial distribution of surface uplift in a sector of the Andean chain and its implications for supergene ore deposits formation, 10th International Conference on Geomorphology, Coimbra, Portugal, 12–16 Sep 2022, ICG2022-418, https://doi.org/10.5194/icg2022-418, 2022.