Main Valley Research Articles

Chronology of Glacial Advances and Deglaciation in the Encierro River Valley (29° Lat. S), Southern Atacama Desert, Based on Geomorphological Mapping and Cosmogenic 10Be Exposure Ages

The high mountain segments of the valleys of the southernmost Atacama Desert of Chile present Late Quaternary glacial landforms that developed in already incised valleys. Glacier advances and deglaciation have left a geomorphic imprint in the southernmost Atacama Desert. In this work, the glacial landforms of the Encierro River Valley (29.1°S–69.9°W) have been revisited and new detailed geomorphological mapping is provided. This work also includes new 10Be exposure ages from moraine boulders and one age from an ice-molded bedrock surface. The former glacier of the El Encierro valley extended 16 km down the valley during the last local glacial maximum recorded by a terminal moraine (ENC 1a) with an exposure age of ∼40 ka. Four inboard moraine arcs were deposited upstream in telescopic patterns (ENC 1b–d), whose exposure ages range between ∼25 and ∼33 ka (ENC 1d). Exposure ages between ∼17–24 ka on lateral moraines (ENC 1L) developed during the later ice recession of the ENC 1 drift. Thus, the ice mostly disappeared in the main valley before ∼18 ka, as is also supported by the exposure age obtained from an ice-molded bedrock surface. Seven kilometers up the valley from the ENC 1, the ENC 2a–d moraine arcs correspond to a small ice advance by ∼17–20 ka. The last glacial advance (ENC 2), which occurred after deglaciation of the last local glacial maximum (ENC 1), coincides with the start of the Heinrich Stadial Event 1 (HS1; 18–14.5 ka), which is thought to play a direct role in the last glacial termination in the Andes.

A New Look at Excavation Techniques and Design of Rock-Cut Architectures

Rock-cut architecture is an essential yet little-known type of vernacular architecture whose nature is different from what we understand by the term “architecture”. This research seeks to answer the question of which technics, designs and digging procedures have been applied in this type of vernacular architecture. Out of the 300 rock-cut buildings and complexes found in Iran, nearly 70 were functionally assessed. Ten complexes were found to serve residential functions in different climates. Technique, type and the settlement context material were also briefly compared and contrasted, and thus, three general excavation techniques were recognized. The largest rock-cut residential complex in Iran, Meymand, was selected as the main case study. Fifty residential units in the oldest part of the village in two regions on both sides of the main valley were studied in terms of technique and design style. They were also compared and contrasted. The quantitative data obtained in this section were compared and contrasted using the descriptive statistical method. Although the rock-cut buildings are dispersed throughout Iran, three main techniques were employed to excavate them. Most of them were excavated using two or three of the said techniques. Application of the fine technique and the size of the particles constituting the settlement context are the two factors determining the quality of excavation. The findings in the area of special climatic design standards and technologies not only give us a better insight into rock-cut architecture but also contribute to setting some standards for design and construction of rock-cut buildings in the present era.

Geologic, Geomorphologic, and Climatic Preparatory Conditions for the Evolution of the Dangkhar Landslide, Himachal Pradesh, India

Abstract With an estimated volume of approximately 15 to 20 km3, the Dangkhar landslide located in the Spiti valley, Himachal Pradesh, India, is one of the largest landslides on earth. Its initiation is geochronologically constrained to have occurred during the late Pleistocene and may be related to glacial retreat following local last glacial maximum, which, depending on the source, occurred around 80 to 30 ka years ago. There is significant value in understanding the causative factors contributing to such an enormous and rare event. On the basis of comprehensive field studies and laboratory investigations, it is concluded that erosional, structural, and depositional features within and surroundings of the Dangkhar landslide are critical for understanding landslide initiation and its long-term behavior. The landslide developed as a block slide along a synformal flexure, and through-cutting lateral valleys fulfill the kinematic conditions for creating a massive removable block of earth. Deposits of weakly cemented and crudely bedded carbonate breccias in the landslide’s toe region represent depositional activity during recession of the main valley glacier, and cross-cutting structural relationships involving ground ruptures (lineaments) and rock glaciers in the head region record long-term, ongoing landslide deformations subsequent to its initiation. Stable isotope signatures of samples indicate presence of freshwater associated with the formation of breccia deposits. While many details concerning the timing and development of the Dangkhar landslide remain unknown, recent studies illuminate some very important aspects. The glacial history of the Spiti valley combined with structural kinematics are clearly important factors concerning landslide development. Also important are constraints concerning the minimum age of landslide initiation after recession of a valley glacier, and structural evidence documenting long-term ongoing slope deformations.

More than heavy rain turning into fast-flowing water – a landscape perspective on the 2021 Eifel floods

Abstract. Rapidly evolving floods are rare but powerful drivers of landscape reorganisation that have severe and long-lasting impacts on both the functions of a landscape’s subsystems and the affected society. The July 2021 flood that particularly hit several river catchments of the Eifel region in western Germany and Belgium was a drastic example. While media and scientists highlighted the meteorological and hydrological aspects of this flood, it was not just the rising water levels in the main valleys that posed a hazard, caused damage, and drove environmental reorganisation. Instead, the concurrent coupling of landscape elements and the wood, sediment, and debris carried by the fast-flowing water made this flood so devastating and difficult to predict. Because more intense floods are able to interact with more landscape components, they at times reveal rare non-linear feedbacks, which may be hidden during smaller events due to their high thresholds of initiation. Here, we briefly review the boundary conditions of the 14–15 July 2021 flood and discuss the emerging features that made this event different from previous floods. We identify hillslope processes, aspects of debris mobilisation, the legacy of sustained human land use, and emerging process connections and feedbacks as critical non-hydrological dimensions of the flood. With this landscape scale perspective, we develop requirements for improved future event anticipation, mitigation, and fundamental system understanding.

Six years of electrified convection over the island of Corsica monitored by SAETTA: General trends and anomalously electrified thunderstorms during African dust south flow events

By means of the SAETTA 3D lightning mapping array, the total lightning activity has been detected in a 240 km × 240 km square domain centred on the island of Corsica located in the West Mediterranean basin, and characterized by a maritime and mountainous environment, with a complex and relatively high relief. The study period covers the months from April to December of the 6 years from 2014 to 2019. Observations are reported with a horizontal resolution of 1 km and a vertical resolution of 0.1 km in terms of density of VHF sources emitted by lightning, and of number of lightning day, in plane- and vertical- projections. Vertical distributions of VHF sources are also provided monthly for the whole period and over the full domain. These 3D long term observations show that the number of lightning days is more important on the main relief of the island. The density of VHF sources exhibits a sharp maximum over the confluence area of the 3 main valleys in the center of the northern part of the island, characterized by a recurrent and vertically well developed lightning activity. The period from 11:00 UTC to 14:00 UTC in July, and in a lesser extent in June and August, is at the origin of this density maximum. This behavior is thus due to a diurnal convection. The whole lightning activity is characterized by 2 maxima in June and September. The first one is linked with the diurnal convection in phase with the maximum elevation of the Sun. The second one must be due to usual large-scale organized thunderstorm events of the fall season. The vertical distribution of VHF sources exhibits an increase in the number of VHF sources from April to August at all altitudes, as well as an increase in the altitude of the main upper peak (from 5.8 km to 10 km) and of the secondary lower peak (from 4.2 km to 6.7 km) of this distribution. From August to December, the opposite evolution appears, except that October is characterized by a strong anomaly with a single intense lower peak at 5.5 km, apparently due to 2 strong events corresponding to anomalously electrified thunderstorms. Several of these anomalously electrified thunderstorms (negative dipoles) are reported. They are all characterized by the movement of cloud cells spatially small and relatively undeveloped vertically propagating from southwest to northeast and associated with a strong transport of desert dust from the African continent. The analysis of the meteorological environment of some of the studied events allows concluding that in each of the studied cases elevated convection was triggered, above the relatively dry atmospheric boundary layer characterized by a strong convective inhibition. The low cloud liquid water content which is a key parameter of the non-inductive charging process is probably a good candidate to explain the anomalous electrification of these events.

Holocene aggradation history of the Murcia alluvial valley: Insights into early Rome's paleoenvironmental evolution

Through the analysis of seven 15–30 m deep boreholes drilled in the western sector of the Circus Maximus we reconstruct the aggradational history of one main tributary valleys of the Tiber River in Rome, the Murcia Valley (Vallis Murcia). Consistent with recent acquisitions in the Tiber Valley, we identify a Bronze Age (4500-3000 yr BP) paleogeographic setting characterized by the lowering of the drainage network base level. This would have created a dry alluvial plain, suitable for human settlement. We also find evidence for dramatic overflooding which occurred during the 6th century BCE and was responsible for the rapid rise from 2 to 6 m a.s.l. of the valley floors within the Tiber catchment basin in Rome. We suggest that these paleogeographic features can be identified in mythical and ethno-historical accounts of early Rome.Besides providing insights into the paleolandscape and anthropogenic interventions in the Murcia Valley, these previously unrecognized hydrological dynamics may attest to paleoclimatic fluctuation that have occurred since 5000 yr BP. Contrary to the dry and cold conditions prevalent during the Bronze through the Iron Age, the exceptional flooding events of the archaic period suggest a shift in climatic trends. However, tectonic and anthropogenic factors could have also had a combined and cumulative effect, requiring detailed paleoenvironmental and palaeolandscape studies.

Constraining the formation of paleolake inlet valleys across crater rims

Impact crater lakes with an inlet valley were common on Mars during past epochs. However, it has not been established exactly how impact craters with initially high-standing rims were breached by an inlet. We investigated four potential mechanisms for inlet valley breach formation: (1) rim erosion, (2) depositional rim burial, (3) drainage head erosion, and (4) overflow. We used remote sensing measurements to assess the relative likelihood of these mechanisms for 39 crater paleolake inlet systems, keeping in mind that either a single mechanism or multiple mechanisms may have occurred. Our findings indicate that crater degradation associated with (1) rim erosion and/or (2) depositional rim burial played an important role in establishing connections between exterior fluvial systems and crater interiors, especially during the late Noachian - early Hesperian valley network era. Isolated fluvial valleys, interpreted to post-date the main valley network era, breached craters in a wider range of degradation states compared to valley network-fed craters. Interestingly, in many cases, these younger systems accomplished a comparable magnitude of fluvial erosion via drainage head erosion and across crater rims as the valley network inlets, despite differences in broader landscape dissection. This finding suggests fluvial activity was able to accomplish comparable geomorphic work during later periods of Mars' history, at least locally. Our catalog of analyzed paleolakes includes Jezero crater, and so our work provides broader context for in situ rover analyses at this site.

New chronological constraints on the Plio-Pleistocene uplift of the Guizhou Plateau, SE margin of the Tibetan Plateau

The Guizhou Plateau represents a geomorphic transition between the Tibetan Plateau and the Yangtze River Plain. It likely formed in response to the propagation of surface uplift in southeastern Tibet during India-Eurasia continental collision. However, the uplift history of the region is unclear largely due to a lack of datable material. The bedrock geology is dominated by carbonate rocks, which contains numerous multi-level caves in the main river valleys that are linked to the river incision history. Cosmogenic 26 Al and 10 Be burial dating of sediments in caves and river terraces from the northwestern and southern plateau reveals the fluvial chronology and provides the first direct determination of long-term river incision rates. The caves and terraces on the Liuchong River in NW Guizhou yield burial ages of between 0.41 ± 0.12 Ma and 2.85 ± 0.21 Ma, indicating an average incision rate of 57 ± 3 m/Ma. Four level caves at Libo in southern Guizhou yield burial ages of between 0.56 ± 0.16 Ma and 3.54 (+0.25/-0.22) Ma, indicating slightly slower incision rate (47 ± 5 m/Ma). These new results imply that the high elevation of the Guizhou Plateau had developed before the Late Pliocene, and that surface uplift during the Late Cenozoic was largely uniform across the region.

Late Pleistocene glaciation history of the southern Black Forest, Germany: 10Be cosmic‐ray exposure dating and equilibrium line altitude reconstructions in Sankt Wilhelmer Tal

ABSTRACTDuring the Late Pleistocene, an ice cap temporarily rested on the highest summit of the Black Forest, Feldberg, and on the surrounding region. Moraines inside the last glaciation maximum ice extent document subsequent glacial standstills and/or re‐advances, but the chronology of the deglaciation remains largely unknown. In Sankt Wilhelmer Tal, moraines were mapped, and suitable moraine boulders were sampled for 10Be cosmic ray exposure (CRE) dating. Equilibrium line altitudes (ELAs) during moraine formation were reconstructed to evaluate whether these can be used for local stratigraphical correlations. Geomorphological mapping revealed numerous ice‐marginal positions in the main valley and in two tributary valleys. CRE ages and ELAs indicate two discrete phases of glacial standstills and/or re‐advances by 17–16 ka at the latest and no later than 14 ka, respectively. Differing ELAs across the study area preclude the use of ELAs for local stratigraphical correlations. Recalculated 10Be CRE ages from other localities in Central Europe indicate similar periods of moraine formation, thus raising the question of a common climatic forcing. Additional sets of CRE ages are needed to answer this question. In addition, future studies should concentrate on determining the age of the last glaciation maximum in the Black Forest.

THE MALE OPILLIA MORPHOLOGICAL ANALYSIS OF RELIEF

The Male Opillia morphological analysis of relief has been carried out on the basis of constructed morphological maps on the scale of 1:50 000 for the key part of the Zubra – Sukhodilka watershed. The morphological mapping lies in taking into consideration dotted, linear and areal elements of relief. The absolute heights of the study area are between 255 and 405 meters high (highland level – 330-405 m, lowland level (main valleys) – 255–290 m). The relative heights of the Zubra River Basin are between 50 and 100 m, Davydivka–Sukhodilka River Basin – between 70 and 130 m. Four main linear elements of relief are thalwegs, combes, convex and concave bends. The most common linear elements are thalwegs. They are the bottoms of shallow river valleys, arroyos, and largest gullies. The main direction of linear reach is diagonal (NW–SE). The convex bends delineate the highland surfaces and flats. They also separate gentle watershed slopes from steep valley slopes. The concave bends usually are the borders of greater river valleys. These elements of relief are entirely isolated, which demonstrates a discernible contact between slopes and bottoms. The combes are the least common linear elements. It is connected with the roundness and alignment of highland surfaces and a small number of sudden changes of directions of horizontals on the straightforward slopes. The dotted elements of relief are submitted as high points. Most high points are rounded. The areal elements of relief are submitted as highland (watershed) surfaces, flats, bottoms of valleys, and different shapes of slopes, according to the cross-section and plan. The highland surfaces are quite noticeable. Their absolute height is estimated between 350 and 380 m. The highland surfaces don’t occupy the upper parts of interfluves; they are divided into two parts. The shape of highland surfaces is strongly stretched along. The nature of morphology of the surface of relief is weakly curved and flat according to the cross-section, and weakly curved and wavy according to the longitude. The surfaces of the flats are subhorizontal elements of relief, which are an intermediate position in relief. These surfaces are bounded by one or two concave bends. The bottoms of the valleys of the Zubra are 190–770 m in width, the Davydivka – 190–770 m, the Sukhodilka – 140-820 m. The shape of the cross-section is predominantly flat, and only in shallow valleys it’s partly concave. The slopes occupy much of the study area so that they prevail over subhorizontal surfaces. The convex slopes prevail; the least common are concave slopes. Key words: morphological analysis of relief; morphological map; elements of relief; Male Opillia.

Flash Flood Modeling Using HEC-RAS (2D) model on Wadi Reem in the western region, Kingdom of Saudi Arabia

Various infrastructures in Saudi Arabia are affecting by floods and rainfall that may damage constructions at urban areas due to water flows in the main valleys and streams. Asser Region in western Saudi Arabia is characterized by its high rainfall intensity that leads to flash floods. The present study aims to evaluate and identify potential floods in coastal areas of Wadi Reem basin and to show the urban areas exposed to flooding with flood water in the coastal city. Runoff calculation is an important part of regional runoff forecast and water resources evaluation model. The Soil Conservation Service (SCS) curve number (CN) model developed by the U.S. Department of Agriculture National Resources Conversion Service (NRCS) is the most popular and widely applied model for direct runoff estimation. The current work used HEC-RAS (2D) in order to simulate Flood map depth and velocity in Wadi Reem coastal areas. Watershed and its stream was delineated using digital elevation model (DEM) and morphological parameters calculated using Watershed Modeling System (WMS). Rainfall frequency analysis was performed for selected three rainfall gages using annual maximums of 24-h rainfall. This study deals with geographic information systems (GIS), hydrologic modeling (water modeling system, WMS), and hydraulic modeling (Hydrologic Engineering Center River Analysis System, HEC-RAS) to evaluate the impact of flash flood hazards on Wadi Reem coastal area.

СТРАТИГРАФИЧЕСКОЕ ЗНАЧЕНИЕ АЛЛЮВИАЛЬНЫХ ОТЛОЖЕНИЙ ГОРНОГО АЛТАЯ В ПОЗДНЕМ НЕОПЛЕЙСТОЦЕНЕ И ГОЛОЦЕНЕ

It is shown that representative sections of the Late Pleistocene alluvial deposits are found mainly in planations of main valleys and intermountain basins of the Gorny Altai. The data of optically stimulated luminescence and radiocarbon dating characterizing the Malyi Yaloman alluvium in the stratotypic Malyi Yaloman section and in same-age reference sections in the upper, middle and lower reaches of the Katun River are presented. That implied the regional stratigraphical significance of the Malyi Yaloman alluvium and it attribution to the epoch separating two Late Quaternary glaciations of the Gorny Altai. The question is raised of the need to identify the stratigraphical significance of regional and local events that caused not only glacial, but also seismic damming of the Gorny Altai valleys in the Late Pleistocene.

Estimation of Surface Runoff to Bahr AL-Najaf

The estimation of the amounts of Surface runoff resulting from rainfall in the water basins is of great importance in water resources management. The study area (Bahr Al-Najaf) is located on the western edge of the plateau and the southwestern part of the city center of Najaf, with an area of 2729.4 (km2). The soil and water assessment tool (SWAT) with ArcGIS software was used to simulate the runoff coming from the three main valleys (Kharr (A and B)), Shoaib Al-Rahimawi, and Maleh), that contribute the flow to the study area. The results of the model showed that the SWAT software was successfully simulating the flow conditions based on the coefficient of determination (R2), the Nash coefficient (NSE), P-factor, and R-factor for calibration (validation) ranged between 0.59-0.62 (0.51-0.59), 0.59-0.66 (0,.60-0.62), 0.57-0.76 (0.62-0.76), and 0.58-0.74 (0.55-0.70) respectively for these valleys. Moreover, the sensitivity results revealed that the most sensitive parameters in (SWAT-CUP) SWAT calibration and uncertainty programs are the curve number (CN2) for the runoff, soil available water capacity (SOL_AWC), and Saturated hydraulic conductivity (Soil_k), according to the calibration results for the main three valleys related the study area. Three hypothesis scenarios were implemented according to the assumed amount of precipitation that would submit a water level of 16,18, and 22 (m.a.m.s.l.) which would result in filling with the bounded lake, the whole study area, and exceeding the boundaries to flood part of the ancient Najaf City.

High lead level in the Alps in XIXth century, learning from the analysis of 138 historical hair stands

Analysis of hair is known to provide useful information about environmental and toxic exposures. Very little historical use has been made of this type of investigation. Here we study 138 human hair samples from 19th century in France.In order to examine the potential association between contamination and historical health impacts, we characterized contamination by 33 elements in a set of hair strands sampled during the last quarter of the 19th century in the Savoy region of France.After a selected washing step on 138 hair strands conserved at the Museum National d’Histoire Naturelle in Paris (France), we assessed the presence of inorganics by ICP/MS, and lead level was higher than values reported in literature. We then compared concentrations and distributions between women and men, sampling locations and crossing gender and geographical origin.Hair lead level was high throughout Savoy at the end of the 19th century: significantly higher for people living in towns or industrial valleys, and lower for those of countryside and mountains areas. Environmental and economic changes (industrialization and urbanization with water adduction and leaded paints), living habits (kitchenware, cosmetics, wine, and tobacco), and local features (mines exploitation, railroad development, and industrialized narrow valleys) could be envisaged for explaining the level of lead contamination. In the same period, the two main industrial valleys of Savoy (Maurienne and Tarentaise) had high rates of endemic goiter and cretinism and among the highest hair lead levels. Other lines of evidence will need to be explore to investigate a possible link between historical Pb exposure and goiter in the study area.

NEW FOUNDS EUPHORBIA VALDEVILLOSOCARPA ARVAT & NYÁR. (EUPHORBIACEAE) IN LOWER DNISTER-TILIGUL INTERFLUVE

Aim. The species Euphorbia valdevillosocarpa is listed in the Red Data Book of Ukraine (2009), where it has the category of protection "endangered". It also has scientificimportance as a Bessarabian endemic on the eastern border of the range. The said species had not been observed in the lower reaches of the Dniester-Tiligul interfluves before. Methods. The floraof the region was studied by means of the route method in 2018-2020. Results. Near village Budiachky, in the valley which connects train station «Kar-pove» (Odesa-Rozdilna) and village Egorovka (on the coast of the Hadzhibeiskyi estuary), new for Odessa region locality of Euphorbia valdevillosocarpa wasfound. The place is located on the west slope, which is in the main valley. Near the site there is an abandoned quarry for shell mining. Plants of Euphorbia valdevillosocarpa were found only on the slope of the northern exposure. 20 plants of E. valdevillosocarpa were found, for each there were from 10 to 35 stems. Apparently due to unfavorable weather conditions in the region in 2020 (drought) plants are significantlysmaller in size, compared to dry specimens of stems from the previous year (to 0.95-1.00 m). The main part of the stems is vegetative, only a third part of the plants have remnants of inflorescences. On 06.2020 some specimens had re-blooming on several stems. Conclusions. The study area does not belong to those that have environmental sig-nificance.Localities of the species in Odesa region are represented only in Tarutyn` district. Thus, the locality near v. Budiachky is the most eastern point in the region. Since sozophytes of different levels of protection are also noted here, it is necessary to create a protected area.

Neuro-medical manifestations of fluorosis in populations living in the Main Ethiopian Rift Valley.

Prolonged exposure to higher concentrations of fluoride (> 1.5mg/L) is associated with dental and skeletal fluorosis. The effects of fluoride on dental and skeletal system have been studied extensively; however, the neurological consequences of fluoride in population-based studies are limited. The study aims to assess the epidemiology of neurological and other manifestations of fluorosis among rural populations living in the Main Ethiopian Rift valley. In this cross-sectional study, we enrolled 316 individuals from 23 rural communities in the Main Ethiopian Rift valley. Fluoride concentration was measured in drinking water samples collected from 23 community wells. Association between fluoride concentrations and clinical features of fluorosis was assessed using student t test, chi square, multivariable regression using adjusted odds ratio (OR). The mean fluoride concentration in the drinking water was 6.8 ± 4.3mg/L (range: 0.3-15.5mg/L). At least one clinical sign of skeletal fluorosis was observed in 54.4% (n = 175) of the study participants. Headache and joint pain reported by 67.1% and 56.3% of the participants as the most common neurological manifestation, and skeletal fluorosis symptom, respectively. The mean fluoride level was higher for those individuals who reported paresthesia compared to those with no-paresthesia. Loss of appetite, constipation, and fatigue were reported by 48.0%, 45.6%, and 56.6% of the participants, respectively. Signs of crippling fluorosis were observed in small proportion (1.6%) of the participants. Individuals who reported headache are most likely exposed to higher fluoride concentrations in drinking water compared to those reported no-headache (p < 0.001). The study demonstrates high prevalence of neuro-medical manifestations of fluorosis in population living in the Main Ethiopian Rift valley. Fluoride concentration in drinking water and joint pain were independent predictors of fluorosis.

Effects of mantle dynamics on estimating effective elastic thickness of the lithosphere

The understanding of the lateral variations in the lithospheric strength can help in identifying the distribution pattern of surface deformation and its response to long-term forces that are related to deep Earth processes. Former studies suggest that Afar and the Ethiopian Plateaus are not in isostatic equilibrium indicating the presence of deep compensation processes. We estimated the effective elastic thickness of the lithosphere (Te) over Ethiopia and its surrounding region using a method that combines the Vening Meinesz-Mortiz and flexural theory of isostasy in a spherical harmonics domain. Our effective elastic thickness model is different from those presented in the previous similar studies, because of considering the effects of mantle dynamics. We incorporated the uplift forces due to mantle plume in additions to surface and sub-surfaces loads, like topographic/bathymetric masses, crustal crystalline and sediments in our method so that it becomes more appropriate for the regions. In addition, laterally-variable models of upper mantle density, Young's modulus and Poisson's ratio have been considered from the CRUST1.0 model. We found a significant improvement of the solution in the Te estimate with consideration of the dynamic effects when we compared it with other studies especially in Afar, the Ethiopian plateaus, and the Main Ethiopian Rift valley. Our results are also consistent with significant lithospheric strength present in cratonic formations, with maximum of Te in Sudan and Tanzanian Cratons. Low Te was found over different tectonically active places such as, Afar and the Main Ethiopian Rift valley.

Properties of secondary xylem of mature oaks in southwest Germany formed after extreme drought stress in summer 2018

The effect of the extreme summer drought and heatwave 2018 in Central Europe on wood properties of oaks at four sandy valley river sites (Quercus robur L.) and one south-exposed schist slope (Qu. petraea (Matt.) Liebl.) in the middle Rhine and lower Main valley were studied and compared to well-watered trees from a riparian stand. While properties of the 2018 tree rings mostly resembled those of the previous (wet) year, significant decreases in Δ13C, wood density and ring width occurred in 2019 at most drought-prone sites. In the sandy sites, ring widths correlated with previous-year precipitation from June to August over a 20-year period. In organs formed in 2018, in general, decreasing Δ13C values were obtained in the order leaves, twigs, wood and acorns, with the values from acorns often resembling those from 2019-year rings. The observed changes indicated an increased intrinsic water use efficiency and lack of starch reserve formation during the unprecedented hot and dry summer 2018. Qu. petraea revealed quite different values from Qu. robur (lower Δ13C, wider and denser year rings), but qualitatively showed the same reaction to the drought in 2018, except for an enhanced formation of tyloses in recent-year tree rings.

Aras Nehri Vadisi ve Yakın Çevresinin Jeomorfolojisi (Kağızman-Gaziler Arası)

The purpose of this study, which covers the Aras River valley and its immediate surroundings, which drained the Kagizman Depression in the Eastern Anatolia, Erzurum-Kars Section is to deal with the valley development process of the river that settled in the region by incising the Kars Plateau, its geomorphological features, its response to tectonic movements in the area and the factors affecting the morphological structure of the region. The selected research area is both in an important point in terms of the relation of the tectonic-fluvial system and covers the Aras River valley, one of Turkey's large rivers, so it is remarkable. In the study, the geomorphological units in the Aras River valley, mainly the river terraces and the river channel were mapped, the areal and metric distributions of the terraces were made, and various maps and sections of the area were created. In the field studies carried out, 3 terrace levels located at 10-25 m, 55-60 m and 110-120 m altitude from the current riverbed were determined. The internal structures of these terraces, which are important paleogeographic findings, are generally composed of coarse sediment and are mostly similar to each other. Besides, Aras River, which presents a typical braided river pattern in the study area, exhibits forced meandering due to the accumulation alluvial fans developing along the main valley.

Geological control of young orogenic mountain morphology: From geomorphological analysis to reinterpretation of geology of the Outer Western Carpathians

The paper presents a new concept of geological control of the Outer Western Carpathians (OWC) morphology. The establishment of the Carpathians' morphology dates back to the stage of evolution of sedimentary basin, when huge blocks of solidified rock massifs were gravitationally displaced into the foreland sedimentary basins, forming finally isolated hills. The altitudinal difference between the Beskidy Mts. and the Carpathian foothills is caused by the structural positions of these two segments of rock massifs within the orogenic megastructure during the compressional stage. Indeed, the tectonic elements that formed during the earliest stage of compression took (and still take) the highest structural and altitudinal position, whereas the elements incorporated into the orogen as the last have taken a lower topographic position, forming a belt of foothills. Therefore, this difference in topography is not related to rock resistance only, as was previously thought. The rotation of the Carpathian blocks during the orogenic thrusting and the formation of strike-slip fault zones parallel to the Carpathian tectonic thrusts formed a flower structure, which has played a significant role in morphology (insular character of). During the stage of secondary tectonic deformation – including the rotation of the Carpathian tectonic segments, strike-slip faulting and the radial extension and large extensional collapse of the Carpathian massifs – the principal features of the Carpathian relief as well as the main river valleys were formed. Gravitational collapse resulted in back-thrusting and the tectonic exhumation of the Carpathian massifs, which helps to explain the problem of seemingly large denudation of the Carpathian overburden of a thickness estimated at several kilometres. Chaotic complexes (synsedimentary and syntectonic mélanges), which frequently occur in the Carpathians, are very important for the Carpathian morphology and river valley development (controlled not only by faults) as well as the formation of isolated hills. Analysis of the Carpathian morphology supported by the Bouguer's gravity anomalies map, and geological data allow us to present a new hypothesis that the Carpathians were formed as a huge regional flower structure, without the participation of subduction, which has formerly been considered to play the crucial role in the formation of the Carpathian orogen.