Bolkar Dağları kuzeydoğusunun glasyal morfolojisi ve döküntüyle örtülü buzulları

In this research the glaciers and glaciated areas of northwest of Bolkar mountains and their geographical conditions have been studied. Recent debris-covered glaciers have been determined in the higher (>2900 m) parts of north and, partially, northeast-facing cirques of two glaciated areas of Pleistocene. The surface area of the largest glacier (Medetsiz) of seven glaciers in Karagöl and Alişan Glaciated Areas is 0,23 km2. On the other hand, Eğerkaya East Glacier occupies a confined place of 0,09 km2. While all the glaciers display the evidence of glacial karst, the Kopukgöl Glacier has exceptionally three supraglacial lakes. In the light of previous data, it is concluded there have been no notable regression in the terminal of the glaciers that since last 60 years. Due to the presence of a debris cover over the glaciers that hampers supraglacially melting, it is possible to suggest that englacial and subglacial ablation should be accounted for of the ablation of glaciers.Bu çalışmada Bolkar Dağları’nın kuzeydoğu kısmındaki buzullaşma alanları ve güncel buzullar ile coğrafi koşulları incelenmektedir. Araştırma kapsamında Pleistosen’de şekillenen iki büyük buzullaşma alanının 2900 m’den yüksek, kuzey ve kısmen kuzeydoğu bakısı olan sirk alanları içinde güncel döküntü örtülü buzullar belirlenmiştir. Karagöl ve Alişan buzullaşma alanlarındaki toplam yedi adet döküntü örtülü buzuldan en büyüğü (Medetsiz Buzulu) 0,23 km2, en küçüğü (Eğerkaya Doğu Buzulu) 0,09 km2dir. Üzerlerinde buzul karstı izleri taşıyan buzullardan sadece Kopuk Buzulu’nda üç adet buzul üstü göl bulunmaktadır. Araştırma alanına ilişkin gerçekleştirilen önceki çalışmalardan elde edilen bilgiler ışığında, buzulların terminalinde son 60 yılda belirgin bir gerileme olmadığı anlaşılmaktadır. Üzerlerinin örtülmüş olması sebebiyle ablasyonun buzul yüzeyinden değil buzulun içi ve buzul altından olduğu sonucuna ulaşılmıştır

Seismic history of western Anatolia during the last 16 kyr determined by cosmogenic 36Cl dating.

Western Anatolia is one of the most seismically active regions worldwide. To date, the paleoseismic history of many major faults, in terms of recurrence intervals of destructive earthquakes, their magnitude, displacement, and slip rates is poorly understood. Regional crustal extension has produced major horst-graben systems bounded by kilometer-scale normal faults locally in carbonates, along which vertical crustal displacements occurred. In this study, we explore the seismic history of western Anatolia using 36Cl exposure dating through study of well-preserved carbonate normal fault scarps. To accomplish this, 36Cl concentrations in 214 samples from fault plane transects on the Rahmiye and Ören fault scarps were measured and compared with existing 36Cl measurements of 370 samples on five fault scraps in western Anatolia. At least 20 seismic events have been reconstructed over the past 16 kyr. The age correlation of the seismic events implies four phases of high seismic activity in western Anatolia, at around 2, 4, 6, and 8 ka. Slips are modeled ranging between 0.6 to 4.2 m per seismic event, but are probably the result of clustered earthquakes of maximum magnitude 6.5 to 7.1. While the average slip rates have values of 0.3 to 1.9 mm/yr, incremental slip rates of the faults range greater than 0.1 to 2.2 mm/yr, showing more activity mostly through late Holocene. Our finding reveals high capability of cosmogenic 36Cl dating to explore seismic behavior of active faults beyond the existing earthquake records. Supplementary Information The online version contains supplementary material available at 10.1186/s00015-022-00408-x

Rapid post-glacial bedrock weathering in coastal Norway

Quantifying bedrock weathering rates under diverse climate conditions is essential to understanding timescales of landscape evolution. Yet, weathering rates are often difficult to constrain, and associating a weathered landform to a specific formative environment can be complicated by overprinting of successive processes and temporally varying climate. In this study, we investigate three sites between 59°N and 69°N along the Norwegian coast that display grussic saprolite, tafoni, and linear weathering grooves on diverse lithologies. These weathering phenomena have been invoked as examples of geomorphic archives predating Quaternary glaciations and consequently as indicators of minimal glacial erosion. Here we apply cosmogenic nuclide chronometry to assess the recent erosional history. Our results demonstrate that all three sites experienced sufficient erosion to remove most cosmogenic nuclides formed prior to the Last Glacial Maximum. This finding is inconsistent with preservation of surficial (<1–2 m) weathered landforms under non-erosive ice during the last glacial period, while simultaneously demonstrating that post-glacial weathering and erosion rates can be locally rapid (4–10 cm kyr−1) in cold temperate to subarctic coastal locations

Geodynamic importance of the strike-slip faults at the eastern part of the Anatolian Scholle: Inferences from the uplift and slip rate of the Malatya Fault (Malatya-Ovacık Fault Zone, eastern Turkey)

Controversy remains over when present-day configuration of the Anatolia boundary faults came into existence, and the issue of what are the driving forces of the Anatolian westward motion. The NW-striking dextral and NE-striking sinistral second-order strike-slip faults at the eastern part of the Anatolian Scholle play a crucial role within these long-lasting discussions, and the NE-striking sinistral Malatya–Ovacık Fault Zone (MOFZ) is particularly important in this ongoing debate. Although the MOFZ is defined as one of the intra-plate structures, it has been proposed that it was an inter-plate fault between the Anatolia and Arabian plates from the latest Miocene to mid-Pliocene and that it has been inactive during the last ca. 3.5 Ma. This study provides results from the first morphochronology-based uplift and slip rate estimates on the Malatya Fault within the southern section of the MOFZ. The cosmogenic isochron burial and cosmogenic depth burial of ages from the sinistrally offset Tohma River remnant terraces enabled us to calculate 1.0 ± 0.01 and 1.12 ± 0.01 mm/yr minimum and maximum horizontal slip rates, respectively, for the last 1.4 ± 0.1 Ma. Furthermore, we conclude that the 96 ± 11 m/Ma mean uplift has been driven by the Malatya Fault. Integrated interpretation of the findings of this study and available data on both the MOFZ and other strike-slip faults at the eastern part of the Anatolian Scholle support the hypothesis that they are plate-boundary related active deformation belts that originated from paleotectonic structures during the tectonic escape of the Anatolian Scholle

The role of frost cracking in local denudation of steep Alpine rockwalls over millennia (Eiger, Switzerland)

Denudation of steep rockwalls is driven by rock fall processes of various sizes and magnitudes. Rockwalls are sensitive to temperature changes mainly because thermo-cryogenic processes weaken bedrock through fracturing, which can precondition the occurrence of rock fall. However, it is still unclear how the fracturing of rock together with cryogenic processes impacts the denudation processes operating on steep rockwalls. In this study, we link data on long-term rockwall denudation rates at the Eiger (Central Swiss Alps) with the local bedrock fabric and the reconstructed temperature conditions at these sites, which depend on the insolation pattern. We then estimate the probability of bedrock for failure through the employment of a theoretical frost cracking model. The results show that the denudation rates are low in the upper part of the NW rockwall, but they are high both in the lower part of the NW rockwall and on the SE face, despite similar bedrock fabric conditions. The frost cracking model predicts a large difference in cracking intensity from ice segregation where the inferred efficiency is low in the upper part of the NW rockwall but relatively large on the lower section of the NW wall and on the SE rock face of the Eiger. We explain this pattern by the differences in insolation and temperature conditions at these sites. Throughout the last millennium, temperatures in bedrock have been very similar to the present. These data thus suggest the occurrence of large contrasts in microclimate between the NW and SE walls of the Eiger, conditioned by differences in insolation. We use these contrasts to explain the relatively low denudation rates in the upper part of the NW rockwall and the rapid denudation in the SW face and in the lower part of the NW rock face where frost cracking is more efficient

Build-up and chronology of blue ice moraines in Queen Maud Land, Antarctica

Blue ice moraines are common supraglacial landforms in Antarctica and they are considered to record the ice volume fluctuations. In this study, we use photogrammetry and the analysis of multiple cosmogenic nuclides (10Be, 26Al, and in-situ 14C) in boulders on three blue ice moraines to explore the timing of ice volume fluctuations in the Sør Rondane Mountains, Queen Maud Land, and provide insights into the role of sediment sources in the reconstruction of their chronology. In the field, we observe that the blue ice moraines are composed of subglacially and supraglacially transported sediments. Cosmogenic 10Be and 26Al exposure ages of 14 surface samples, collected from boulders on three blue ice moraines, range from 15.4 ± 1.1 to 659.5 ± 33.9 ka. 26Al/10Be ratios vary between 3.53 ± 0.20 and 7.01 ± 0.32, and many of these ratios indicate complex exposure histories. In contrast, among nine in-situ 14C exposure ages, five vary between 4.2 ± 0.1 and 22.0 ± 1.3 ka, and four are saturated. We conclude that the accumulation of these blue ice moraines commenced before or during the global Last Glacial Maximum. Our results indicate that surficial sediment sources can yield exposure ages that are older than real exposure age, and exhibit a wider scatter. This can alter the reconstructed chronology of these landforms. The analysis of in-situ 14C has a high potential in tracking the pace of their evolution, especially since the Last Glacial Maximum.ISSN:2666-033

Early Holocene thinning and final demise of the Scandinavian Ice Sheet across the main drainage divide of southern Norway

The thinning and final decay of the Scandinavian Ice Sheet in the Gudbrandsdalen area in central southern Norway is described, based on (1) cosmogenic 10Be surface exposure dating of 25 glacially transported boulders, (2) radiocarbon dating of plant remains in the basal strata in four lakes and (3) mapping of large ice-dammed lakes that formed at different elevations and at different times during the last deglacation. We complement the new chronology with previously published 10Be-ages from the same region. The dated samples are spread from mountain summits 1800 m a.s.l. to the valley floor at 250 m a.s.l. Our results suggest that the ice sheet surface remained well above 1800 m a.s.l. in northern Gudbrandsdalen throughout the Younger Dryas. During the Early Holocene the ice sheet thinned rapidly, at rates estimated to 1.7–5.8 m yr−1. The final phase of deglaciation involved formation of large ice-dammed lakes, most notably the Store Dølasjø which was formed after 10.4 ka BP and finally drained around 10.0 ka BP. The ice-marginal landforms that characterize the mountain region of northern Gudbrandsdalen, i.e., moraine ridges, lateral meltwater channels, as well as deposits and shorelines from ice-dammed lakes, thus collectively originate from a period of rapid ice sheet downwasting over ca. 1600 years.ISSN:0277-379

Brucellosis in pregnancy and its response to the changing immunoglobulin A: A prospective controlled study

Objective: This study aimed to define the rare Brucella infection in pregnancy and its effects on immunoglobulins (Ig). Materials and Methods: This prospective study has conducted Brucella screening using the Rose Bengal test on pregnant and non-pregnant outpatients who did not show any specific Brucella symptoms. The immunoglobulin levels were measured using the enzyme-linked immunosorbent assay. The study group consisted of pregnant women who were at 20 weeks or below gestation and applied to our hospital outpatient clinic for routine check-ups. The control group consisted of healthy patients who applied for routine controls. Results: This study included a total of 584 participants, 293 of whom were controls and 291 were the study (pregnant) participants. The study revealed a 1.5% incidence of Brucella during pregnancy. In acute and chronic Brucella infection, lower levels of IgA response were observed in pregnant cases compared to the control group. Conclusion: Brucella infection is a disease that can cause fetal problems, especially in endemic areas. The role of the altered IgA response in pathologies that are associated with Brucella infection stands out as a new target for disease pathophysiology.Objective: This study aimed to define the rare Brucella infection in pregnancy and its effects on immunoglobulins (Ig). Materials and Methods: This prospective study has conducted Brucella screening using the Rose Bengal test on pregnant and non-pregnant outpatients who did not show any specific Brucella symptoms. The immunoglobulin levels were measured using the enzyme-linked immunosorbent assay. The study group consisted of pregnant women who were at 20 weeks or below gestation and applied to our hospital outpatient clinic for routine check-ups. The control group consisted of healthy patients who applied for routine controls. Results: This study included a total of 584 participants, 293 of whom were controls and 291 were the study (pregnant) participants. The study revealed a 1.5% incidence of Brucella during pregnancy. In acute and chronic Brucella infection, lower levels of IgA response were observed in pregnant cases compared to the control group. Conclusion: Brucella infection is a disease that can cause fetal problems, especially in endemic areas. The role of the altered IgA response in pathologies that are associated with Brucella infection stands out as a new target for disease pathophysiology

Dating of active normal fault scarps in the Büyük Menderes Graben (western Anatolia) and its implications for seismic history

Fault scarps, if well-preserved, include precise evidence of past earthquakes. Using cosmogenic 36Cl dating, the timing and slip of paleoearthquakes are recoverable beyond the available earthquake archives. One of the appropriate seismically active regions to apply 36Cl dating is western Anatolia, where its deformation is influenced by an N-S extensional regime, where the horst-graben structures are characterized by normal faults. We have studied well-preserved (meta-) carbonates Kalafat and Yavansu fault scarps in the westernmost part of the Büyük Menderes Graben within western Anatolia. The distribution of cosmogenic 36Cl against height along the fault surfaces indicates that faults experienced minimum three high paleoseismically active phases. The recovered ages of seismic events are ca. 15, 8.4, and 3.6 ka, with vertical components of slip of ca. 0.7, 0.9 and 3.1 m, respectively, for the Kalafat Fault, and ca. 7.9, 3.4, and 2.0 ka with vertical components of slip of ca. 0.6, 3.5, and 2.6 m, respectively, for the Yavansu Fault. The recurrence interval of active periods is generally becoming shortened over time. The ruptures mostly occurred as clustered earthquakes close in time with magnitudes of 6.5–7.1. The vertical slip rates of >0.1, 0.1, and 1.5 mm/yr, and >0.1, 0.8, and 1.9 mm/yr were calculated for the Kalafat and Yavansu faults, respectively. Long-term slip rates were also estimated about 1.0 and 0.6 mm/yr for the Kalafat and Yavansu faults, respectively. Considering the fault lengths, they are capable of producing earthquakes with magnitudes larger than 6.5, and are seismogenic faults