2018 International Summer School on rockslides and related phenomena in the Kokomeren River valley (Kyrgyzstan)

Information about the next Kokomeren Summer School that will take place on August 15–30, 2018, is provided.     

Holocene palaeoflood events recorded by slackwater deposits along the middle Beiluohe River valley,middle Yellow River basin,China

Palaeohydrological investigations were carried out in the middle Beiluohe River valley in the middle Yellow River basin. Palaeoflood slackwater deposits (SWDs) are natural records of overbank flooding and are often identified in the Holocene aeolian loess–soil profiles along the river valley. Three bedsets of palaeoflood SWDs were found within the mid‐Holocene Climatic Optimum palaeosol (S₀) on the right riverbank. Both the sedimentary and the analytical results, including magnetic susceptibility, grain‐size distribution and concentrations of chemical elements, indicate that these palaeoflood SWDs were deposited from the suspended sediment load of overbank flooding. We identified three episodes of extraordinary overbank flooding events. These hydro‐climatic events were dated to 7600–7400, 5800–5000 and 4200–4000 a BP, from optically stimulated luminescence (OSL) dating and pedostratigraphical correlation. The minimum flood peak discharges were estimated to have been between 12 600 and 14 100 m³ s^?1 using the slope–area method. These hydro‐climatic events are considered to be a regional expression of known climatic events and demonstrate that the mid‐Holocene climate was far from stable. These results show that the magnitudes of floods are highly sensitive to climate change in semi‐arid and sub‐humid regions with a monsoonal climate.     

Holocene palaeoflood events recorded by slackwater deposits along the lower Jinghe River valley,middle Yellow River basin,China

Palaeoflood slackwater deposits (SWDs), are the natural record of overbank flooding and are often found within aeolian loess‐soil profiles along the river valleys of the middle Yellow River basin. These pedo‐stratigraphic sequences are studied using a multi‐disciplinarily approach to reconstruct Holocene hydro‐climatic variations. Our field investigations along the lower Jinghe River valley have identified palaeoflood SWDs at several sites along the riverbanks based on sedimentological criteria. Analytical results, including magnetic susceptibility, particle‐size distribution and concentrations of chemical elements, indicate that these well‐sorted palaeoflood SWD beds were deposited from the suspended sediment load in floodwaters. We identify two episodes of extraordinary palaeoflood events along the Jinghe River valley. These hydro‐climatic events were dated to 4200–4000 and 3200–2800 a BP, by using the optically stimulated luminescence method in combination with archaeological dating of retrieved anthropogenic remains, and with pedo‐stratigraphic correlations with the previously studied Holocene pedo‐stratigraphy in the Jinghe River drainage basin. The flooding events are therefore considered to be a regional expression of known climatic events in the northern hemisphere and demonstrate Holocene climate was far from stable. This study provides important data in understanding the interactions between regional hydro‐climatic systems and global change in semi‐arid and sub‐humid regions. Copyright © 2012 John Wiley & Sons, Ltd.     

Geological structure of the Ubinka River valley (Northwestern Caucasus)

A thick olistostrome strata of late Paleocene-early Eocene age is outlined in the northern flank of the Northwestern Caucasus folded structure in the Ubinka river valley, which shows the significant role of earlier Cenozoic tectonic movements in forming the alpine structure of the region. The largest part of the strata is composed of dark weakly calcareous clays, which were earlier recognized as Lower Cretaceous deposits. Olistoliths and large olistoplaques are mostly of light calcareous rocks in which microfauna of Cenomanian and Maastrichtian ages were discovered in dark clays. A poor series of foraminifers was recognized in the dark clays hosting these olistoliths; this series do not enable one to determine with certainty the age of the strata (of approximately the late Paleocene-early Eocene). Small structural forms were recognized in olistoliths and olistoplaques, which are not traced in the matrix, this indicates that a series of folded and fissured structures were formed before these olistoliths and olistoplaques appeared in the olistostrome strata.     

Geoinformatics in morphological study of River Paglia,Tiber River basin,Central Italy

This work reports the results of a geomorphological study on the River Paglia (Tiber basin, Central Italy), to analyse the historical evolution of the riverbed/floodplain system in its lower valley reaches, upstream the confluence of River Tiber. A morphological–sedimentological approach has been used, starting with an historical analysis and a survey of the forms and sediments in the riverbed/alluvial plain system, in order to reconstruct the current evolutionary trend and to identify the causes and processes leading to changes in natural trends. This approach is not in contrast to the hydrologic–hydraulic one, normally applied in engineering fields, but it is integrated with it in a complementary and parallel manner, in order to achieve the complete knowledge of the river system, result of an investigation multidisciplinary, aimed to define its physical state. Historical data (cartographic documents, digital terrain models—DTM, topographic surveys, aerial photographs, etc.) indicate clear-cut narrowing and deepening of the active channel, manifested after the Second World War and due to the considerable changes which affected the entire fluvial system (from the recovery of land for agriculture near the river, to sediments taken from its bed over the past few decades). The result is a state of great disequilibrium, which is shown in the passage from a braided morphology, observed in the 1950s, to a single channel with low sinuosity (wandering type). This type of morphology is certainly more unstable: in fact, the narrowing and deepening of fluvial sections provide a better hydraulic efficiency for the upstream, so the peak discharge does not overflow. Such peak discharge arrives downstream, next to the confluence with the Tiber River, not laminated, causing serious flooding effects. An increased vulnerability is observed in the last reach, in the areas pertaining to the river, where most of the industrial-economic activities are concentrated and where transportation infrastructures of nationwide importance (Italy’s most important motorway, the A1, and the Rome–Florence–Milan high-speed rail links) are located. The evolution of the Paglia (which is not substantially different from that of many streams in Italy and in general throughout Europe) is affected by severe anthropic constraints and intense exploitation of resources, which have produced a state of disequilibrium approaching irreversibility in an already vulnerable system. Finally, some suggestions for the correct management of the river system are pointed out, with the aim of mitigating the flood risk in the lower Paglia valley.     

Palaeoecological study on the Holocene valley development of the River Main, southern Germany

Tree-ring studies carried out on subfossil oak trunk deposits within the Holocene valley fills of the River Main can reconstruct phases of increased fluvial activities. These phases have been dated on the base of two absolutely tree-ring dated chronologies and in addition by ¹¹C-datings of eleven floating tree-ring scries of subfossil oaks.
Geological-pedological investigations reveal an alternation between increased and reduced fluvial activity during the Holocene.
Periods of increased gravel redeposition are dated by dendrochronology, and by ¹⁴C and cultural findings. Increased fluvial activity becomes more frequent towards Modern Times with culminations in the Middle Atlantic, the Subboreal, the Iron-Roman Age, the Main Middle Ages till earliest Modern Times, and in the last century.
On the sequence of Holocene river deposits there developed specific soil types as indicators for the age of the river deposits since the Last Glacial.
Among other palaeoecological results an important finding is the correlation between tree-ring width, flood-loam sedimentation, and soil development.     

A luminescence dating study of the sediment stratigraphy of the Lajia Ruins in the upper Yellow River valley,China

Pedo-sedimentological fieldwork were carried out in the Lajia Ruins within the Guanting Basin along the upper Yellow River valley. In the eolian loess-soil sections on the second river terrace in the Lajia Ruins, we find that the land of the Qijia Culture (4.20–3.95 ka BP) are fractured by several sets of earthquake fissures. A conglomerated red clay covers the ground of the Qijia Culture and also fills in the earthquake fissures. The clay was deposited by enormous mudflows in association with catastrophic earthquakes and rainstorms. The aim of this study is to provide a luminescence chronology of the sediment stratigraphy of the Lajia Ruins. Eight samples were taken from an eolian loess-soil section (Xialajia section) in the ruins for optically stimulated luminescence (OSL) dating. The OSL ages are in stratigraphic order and range from (31.94 ± 1.99) ka to (0.76 ± 0.02) ka. Combined OSL and ¹⁴C ages with additional stratigraphic correlations, a chronological framework is established. We conclude that: (1) the second terrace of the upper part of Yellow River formed 35.00 ka ago, which was followed by the accumulation of the eolian loess-soil section; and (2) the eolian loess-soil section is composed of the Malan Loess of the late last glacial (MIS-2) and Holocene loess-soil sequences.     

Pleistocene sediments in the Shapkina River valley (Bol’shaya Zemlya Tundra)

Facies-genetic and stratigraphic subdivision of the Quaternary sequence in the Shapkina River valley has been accomplished. The riverbank shows outcrops of three glacial complexes with different mineralogical-petrographic compositions and structural characteristics, which can be correlated and stratificated. Datings of intermoraine horizons (alluvial, marine, lacustrine, and lacustrine-boggy sediments) have been based on the palynological and paleomicrotheriological data. The middle Neopleistocene section can be divided into two till horizons corresponding to two autonomous glaciations (Pechora and Vychegda). They are separated by a member of subaqueous Rodionov sediments. The Pechora till formed in the course of motions of glaciers from the northeast. Glacial horizons are mainly composed of the Vychegda till delivered from the Northwest terrigenous provenance. Lithology of the upper Neopleistocene Polyarnyi till testifies to its formation in the upper course of the river from material delivered from the Northeast terrigenous-mineralogical provenance in the upper course of the river and from Fennoscandian glaciation center in the lower course of the river. The paper presents the first lithological investigation and substantiation of genesis of various facies of Neopleistocene intermoraine marine sediments (sediments of the beach and fore-beach zones and shallow-water shelf).     

克里雅河河谷地貌与塔里木盆地 早—中更新世大湖环境

克里雅河谷现今的地貌特征是其1.09Ma以来演化的结果,记录了构造-气候综合作用下的地表过程.在克里雅河流出西昆仑山山前的支流吾格也克河至克里雅河主支的康苏拉克河段,河谷地貌清楚地分为早期的宽阔河谷地貌和其后明显窄小的峡谷地貌.克里雅河近50年来的平均年径流量约为7.345×108m3,早期宽阔河谷发育阶段的河水年径流量推测值不小于146.9×108m3.这表明当时克里雅河的河水流量远比现今的观测值要高得多,当时上游来水、区域降水远比现在多,塔里木盆地的古气候环境与现今塔里木盆地的荒漠环境迥异.在邻区策勒河西域砾岩中观察到的泥石流沉积表明,早更新世及略早一些,西昆仑山有可观的季节性洪水,那时的克里雅河河谷更加宽阔.因此,早--中更新世塔里木盆地应当存在相当可观的大湖.     

Vertical vulnerability evaluation of middle-low Esino River valley alluvial aquifer (Marche, Italy)

 The methodology applied in this research work allows the evaluation of the vertical vulnerability of the Esino River alluvial aquifer (Marche). Main factors determining the ease with which possible pollutant may come from the soil surface to reach the groundwater beneath, through a prevalently vertical path, have been evaluated. Following a "raster" logic, the study area has been discretized into a set of elemental areas. For each of these areas, dimensionless indices able to characterize the actual possibility for the groundwater to be reached by polluting substances have been estimated. Received: 25 February 1997 · Accepted: 13 November 1997     

Isotope composition of a lithalsa in the Sentsa River valley (East Sayan Mountains)

The ice-rich core formation within the core of the lithalsa in the Sentsa River valley (West Buryatia) was studied. The concentrations of stable oxygen and hydrogen isotopes in the ice were determined, the plant residues in the enclosing deposits were aged. It was found that the lacustrine loams enclosing the ice body were accumulated about 4700–7000 years ago. The ice core of the lithalsa was characterized by δD values from 141.9 to–159.8‰, δ¹⁸O from–19.52 to–21‰, and d _exc within 4.1–17.29‰. Small variations in the isotope composition of the ice–soil material within the lithalsa core point to its formation in an open system with water inflow from outside. The values of δ¹⁸O and δD were much closer to those for recent middle-winter and late-autumn atmospheric precipitation, as well as for riverine water, which pointed to a Holocene age of the ice.     

Connectivity analyses of valley patterns indicate preservation of a preglacial fluvial valley system in the Dyfi basin, Wales

Coastal valleys in the west part of Mid-Wales, such as the Mawddach, Dysynni, Tal-y-llyn and Dyfi, acted as corridors for ice which drained the Welsh Ice Cap during the Devensian. Analyses of detailed digital elevation models, and interpretation of satellite images and aerial photographs, show the existence of large variations in the amount of glacial modification between these valleys. Although all the valleys are glacially over-deepened along late Caledonian fault lines, only the Dyfi basin exhibits a dendritic pattern, with V-shaped cross-profiles and valley spurs typical of valleys formed by fluvial processes. Connectivity analysis of the Dyfi basin shows that it exhibits an almost completely dendritic pattern with connectivity α and β values of 0.74 and 1.01, respectively, with little glacial modification of the preglacial fluvial valley pattern in the form of glacial valley breaching. Several examples of glacial meltwater incision into a well-developed pre-existing river valley system, causing river capture across watersheds, have been identified in the Dyfi basin. The degree of preservation of the preglacial fluvial valley system within the Dyfi basin indicates limited modification by glacial processes, despite the area being subjected to glacier activity during the Late Devensian at least. It is possible that major parts of the basin were covered by cold-based or slow-moving ice, close to, or under, a migrating ice-divide, with the major ice drainage occurring along the weaker zone of the Pennal Fault along which teh Dyfi valley is located, causing minor adjustments to the surrounding interfluves and uplands. It is proposed here that the general river valley morphology of the Dyfi basin is of a pre-Late Devensian age.     

雅鲁藏布江流域古堰塞湖群的发育及其地质意义初探

展布于青藏高原东南部的雅鲁藏布江流域河谷中广泛分布有古堰塞湖沉积,古堰塞湖发育与构造活动、气候变化和地表过程等因素关系密切.在广泛地质调查的基础上,识别出雅鲁藏布江流域的十余个古堰塞湖,通过对其开展沉积学、地貌学和年代学工作,结合前人工作结果,初步建立了古堰塞湖群的地层年代框架.地表残留的古堰塞湖沉积多集中于末次冰期冰...     

Structure and composition of the sedimentary cover in the Knipovich Rift valley and Molloy Deep (Norwegian-Greenland basin)

The multidisciplinary approach is used to analyze the structure of the sedimentary cover in the northern Knipovich Rift valley, Molloy Fracture Zone and synonymous basin, Svyatogor and Hovgard rises, Gorynych Hills, Litvin and Pogrebitskii seamounts, and western slope of the Spitsbergen Archipelago studied in Cruise 24 of the R/V Akademik Nikolaj Strakhov. Materials of the bathymetric survey with multibeam echo sounder, as well as continuous seismic and vertical acoustic profiling, revealed two main (NNW- and NNE-trending) systems of fractures in the neotectonic structure of the region. It was established that a system of NNE-oriented fractures, linear zones of the dominant development of keyboard deformations included, is consistent with the strike of magnetic anomalies reconstructed for this region. Tectonic aspects of the Knipovich Rift and prospects of its further development are considered. Based on the wave field pattern of continuous seismic profiling (CSP) records, four seismocomplexes indicating contrasting sedimentation settings and intense tectonic processes at different formation stages of the northern Norwegian-Greenland Sea are conditionally defined in the sedimentary cover of the study region. It was established the Molloy Fracture Zone is responsible for a system of horizontal reflectors of acoustically transparent structureless light spots (“blankings”) in the upper well-stratified part of the sedimentary section, which are characteristic of areas with ascending pore fluids. The micropaleontological study (palynomorphs of higher plants, dinocysts, planktonic foraminifers, and diatoms) revealed the presence of Miocene assemblages in sediments. Benthic foraminifers include late Paleocene-middle Eocene assemblages. The composition of rock-forming components demonstrates a directed succession of mineral-terrigenous associations from the feldspar-quartz type to mesomictic quartz-graywacke type.     

Spatial characteristics of surface water quality in the Haicheng River (Liao River basin) in Northeast China

Spatial variations of the water quality in the Haicheng River during April and October 2009 were evaluated for the national monitoring program on water pollution control and treatment in China. The spatial autocorrelation analysis with lower Moran’s I values displayed the spatial heterogeneity of the 12 physicochemical parameters among all the sampling sites of the river. The one-way ANOVA showed that all variables at different sampling sites had significant spatial differences (p < 0.01). Based on the similarity of water quality characteristics, cluster analysis grouped the 20 sampling sites into three clusters, related with less polluted, moderately polluted and highly polluted sites. The factor analysis extracted three major factors explaining 76.4 % of the total variance in the water quality data set, i.e., integrated pollution factor, nitrogen pollution factor and physical factor. The results revealed that the river has been severely polluted by organic matter and nitrogen. The major sources leading to water quality deterioration are complex and ascribed to anthropogenic activities, e.g., domestic and industrial wastewater discharges, agricultural runoff, and animal rearing practices.     

River water quality in weathered limestone: A case study in upper Mahanadi basin, India

Stromatolitic limestone and calcareous shale belonging to Chattisgarh Supergroup of Proterozoic age dominate the upper part of the Mahanadi river basin. X-ray diffractogram (XRD) of limestone rocks show presence of a significant amount of calcite, dolomite and ankerite. Shales of various colours contain calcite and dolomite. It is observed that congruent dissolution of carbonate minerals in the Charmuria pure limestone has given rise to a typical karst topography. On the other hand, limestones are also seen to support red and black soil profiles. This indicates that the limestone bedrock undergoes a parallel incongruent weathering, which leaves a residue of decomposed rock. The XRD analyses reveal that the limestone soils thus formed contain an assemblage of quartz, clays and Fe-oxides. It is likely that the silicate component trapped during deposition of the stromatolitic limestone weathers incongruently resulting in diverse soil profiles. Carbonate and silicate mineral weathering schemes have been worked out to explain the soil formation, fixation of Al in clay minerals, and Fe in goethite. The water quality parameters such as Ca, Mg and HCO₃ in the river water suggest under saturation with respect to calcite and dolomite. The mineral stability diagrams indicate that kaolinite and Ca-smectite are stable in the river water environment, hence they occur in suspended sediments and soils. The dominant influence of carbonate weathering on the water quality is observed even in the downstream part of the river outside the limestone terrain.     

山东黄河流域下游土壤粒度和深度试验成果

以黄河流域下游野外获得的土壤粒度和深度纵剖面试验资料为基础，分析了黄河流域下游不同土壤类型区、不同地貌单元的土壤粒级组成、元素在各粒级组中的分配特征和元素在土壤纵剖面中的含量、纵向变化规律，探讨了其在生态地球化学调查中的意义。确定了能代表区域内土壤主要物质组成的粒级范围，提出了本区生态地球化学调查的最佳样品筛分加工方案和表层、深层土壤样品采集的有效深度和层位。     

Estimating groundwater storage changes in the Mississippi River basin (USA) using GRACE

Based on satellite observations of Earth’s time variable gravity field from the Gravity Recovery and Climate Experiment (GRACE), it is possible to derive variations in terrestrial water storage, which includes groundwater, soil moisture, and snow. Given auxiliary information on the latter two, one can estimate groundwater storage variations. GRACE may be the only hope for groundwater depletion assessments in data-poor regions of the world. In this study, soil moisture and snow were simulated by the Global Land Data Assimilation System (GLDAS) and used to isolate groundwater storage anomalies from GRACE water storage data for the Mississippi River basin and its four major sub-basins. Results were evaluated using water level records from 58 wells set in the unconfined aquifers of the basin. Uncertainty in the technique was also assessed. The GRACE-GLDAS estimates compared favorably with the well based time series for the Mississippi River basin and the two sub-basins that are larger than 900,000 km². The technique performed poorly for the two sub-basins that have areas of approximately 500,000 km². Continuing enhancement of the GRACE processing methods is likely to improve the skill of the technique in the future, while also increasing the temporal resolution.