Last Glacial–Interglacial cycle in the evolution of river valleys in southern and central Poland

The Last Glacial–Interglacial cycle is represented usually by several cuts and fills, which have formed 2–3 terrace steps from the Last Cold Stage and by two or more fills of Lateglacial–Holocene age. Their number depends on the size of the river valley and the position in the longitudinal profile. The sequence of changes reflects shorter stadial–interstadial climatic fluctuations. Generally, aggradation dominates during the cooler phases of the Vistulian and during the Interpleniglacial. The most distinct erosional phases occurred during the change from a more oceanic to a more continental climate before the maximum extension of the ice sheet (25–20 ka BP) and during the Upper Pleniglacial–Lateglacial transition (15–13 ka BP). The second phase coincides with the rapid downcutting in the lower course of the main Vistula valley, which had been blocked earlier by the Scandinavian ice sheet. In the Holocene aggradation prevailed, accelerated by anthropogenic soil erosion. It was only in the mountain foreland that shorter-lived hydrological changes resulted in well expressed several cuts and fills.     

Influence of climate on the variability of snails of the genus Viviparus in deposits of the Holsteinian (Mazovian) Interglacial from Ortel Krolewski, eastern Poland

Sediments of palaeolakes located in eastern Poland represent the Holsteinian (Mazovian) Interglacial, which corresponds to the Marine Isotope Stage 11 (MIS 11). Some of these sediments are characterized by an extremely rich occurrence of mollusc shells. A total of 1795 specimens of the snail Viviparus diluvianus were measured from 5 samples collected from a succession of lake deposits at Ortel Krolewski. The sample from the lowermost part of the succession (2.5 m) represents the Picea-Alnus pollen zone of the Holsteinian Interglacial. Samples from 2.0, 1.5, 1.0m are related to the Taxus Zone. Samples collected from the uppermost part of the succession (0.5 m) correspond to the Pinus Zone representing the so-called intra-interglacial cooling. The population of V. diluvianus displays variability correlated with climatic changes. The population from the Taxus Zone is characterized by a higher content of mature forms compared to the earlier population from the Picea-Alnus Zone. Because the mature individuals are slimmer than the juvenile forms, their last whorl is relatively lower and the aperture relatively smaller. In populations from the Taxus Zone the mean slimness of the shell therefore increases, followed by a decrease in the mean relative height of the last whorl and the mean relative aperture height.     

Description and ESR dating of the Holsteinian interglaciation

The classical region of the Holsteinian interglacial is in the vicinity of Hamburg and the Lower Elbe. It is defined on the basis of pollen and is clearly distinguishable from the Eemian interglacial (Hallik, 1960; Müller, 1974). The Holsteinian interglacial is represented by a sequence of sediments up to 100 m in thickness. These consist of limnic, fluvial, and marine beds and show a transgression up to the height of present sea-level.Twenty-seven molluscs from Holsteinian deposits were used for ESR dating. The ages show that the Holsteinian may be correlated with stage 7 of the deep sea record V28-238 (Shackleton and Opdyke, 1973).     

Definition and character of the Regency Interglacial and Early-Middle Pleistocene stratigraphy in the King Valley, western Tasmania, Australia

Interpretation of weathered glacial and interglacial deposits in the lower King Valley suggests that the Early Pleistocene Thureau Formation is conformably overlain by the Regency Formation. Pollen analysis of the Regency Formation provides evidence of a new climatic stage, the Regency Interglacial. The interglacial deposit consists of humified peat overlain by drifted wood and leaves. The pollen analysis shows a transition from montane scrub rainforest to lowland temperate rainforest dominated by Lagarostrobos franklinii, Nothofagus cunninghamii and Phyllocladus aspleniifolius. Trace quantities of the species Quintinia psi-latispora and Gothanipollis perplexus , now both extinct in Tasmania, were also recorded. On the basis of intense chemical weathering and correlation with sediments that have a reversed magnetization the weathered glacial deposits of the Thureau Formation are thought to be older than 730,000 B.P. The eroded interglacial deposit rests on the weathered deposits and is buried by outwash gravels of the David Formation, which was deposited during an ice advance of the Middle Pleistocene Henty Glaciation (c. 150,000 B.P.). Comparison of the Regency site with a site 2 km to the south at Baxter Rivulet shows that the unconformity between the interglacial deposit and the overlying outwash gravel represents the erosion of the evidence for the Middle Pleistocene Moore Glaciation.     

中蒙边界中东段地层划分与对比

中国与蒙古交界地区,早前寒武系—新生界分布广泛,地层划分系统差别较大。根据近年来内蒙古地层年代划分研究成果,初步对中蒙边界中东段蒙古地层岩石、化石进行了整理与划分,并以中国出露的地层为参照,进行中蒙边界中东段地层划分与对比。结果表明,中蒙边界中东段地层具有连续性,可以统一划分对比。     

鄂西清江岩溶与地质灾害的关系

鄂西清江流域碳酸盐岩分布广泛,岩溶地质灾害较为发育。文章在清江流域11个县市地质灾害详细调查成果基础上,运用统计归纳和工程地质类比等方法,分析清江岩溶与地质灾害的关系表现在4个方面:岩溶水系统导致岩溶塌陷（及灾害链）;溶蚀扩张和岩溶化诱发加剧滑坡和崩塌,溶蚀风化形成危岩（潜在不稳定斜坡）;钙质胶结的存在加强了滑坡崩塌的稳定性;岩溶与地质灾害易混淆,以新塘石林为例强调二者之间需甄别。指出碳酸盐岩区地质灾害调查应加强岩溶孕灾地质背景研究;研究钙质胶结的分布规律与加固效果可应用于滑坡和崩塌防治。      

Geomorphic traces of a Weichselian ice stream in the Wielkopolska Lowland, western Poland

Geomorphological analysis of a digital elevation model reveals an extensive zone with uniformly oriented elongated landforms in the middle and eastern Wielkopolska Lowland, directly to the north of the maximum extent of the Weichselian Ice Sheet. Individual linear landforms are up to 10 km long, a few hundred metres wide, and with only a few metres of relief. The belts of linear landforms visible on the surfaces of the uplands are disrupted by subglacial channels and younger river valleys. The character and distribution of both landform types, in relation to the outlines of marginal zones of the Weichselian ice lobes, indicate that their origin was subglacial. The elongated landforms are interpreted as mega-scale glacial lineations (MSGLs) characteristic of palaeo-ice stream zones. The MSGLs occur in a zone 70 km long and 80 km wide and are distinctly divergent towards the maximum extent of the ice sheet. This arrangement demonstrates that they are the record of the terminal zone of the ice stream, whose full size was likely in the order of a few hundred kilometres in length.     

Reflection of the glacial-interglacial cycle in the evolution of the Vistula river Basin, Poland

A variety of factors has controlled the evolution of the Vistula river valley. They include climatically induced changes of the river runoff and sediment load, glacial advances and rapid variations of the base level, as well as the influence of the tectonic factor. The first-order climatic cycles are reflected in separate terrace fills. The second-order fluctuations may be represented by separate cuts and fills, by the change of the facies or by the change in the granulometric composition. The analysis of the changes in the longitudinal profile helped to discover a great variety of different valley reaches and a general tendency to smooth the long profile during the Quaternary.     

中原邙山黄土与末次间冰期以来古季风特征

中原邙山赵下峪剖面出露S10以上黄土地层,厚度大于172.1m。末次间冰期S1古土壤厚15.7m,末次冰期L1黄土厚达77.3m,其中晚冰阶L1LL1黄土、间冰阶L1SS1古土壤和早冰阶L1LL2黄土分别厚41.6m、13.2 m和22.5 m。邙山黄土是厚度最大的晚更新世黄土地层剖面之一,记录了丰富的气候环境变化信息。用SPECMAP氧同位素曲线确定的阶段界限的日历年龄为标定点和磁化率年龄模式,获得相应的时间标尺,据以计算出S2以上各层段的平均沉积速率和分辨率。邙山黄土倒数第二间冰期以来不同冰期或冰阶与间冰期或冰阶的粒度、平均沉积速率和分辨率有很大的差异,其中以末次冰期晚冰阶L1LL1黄土的平均沉积速率为最高,达3.45 mm／a,而末次问冰期S1古土壤的沉积速率亦高达0.28 mm／a。本文主要根据赵下峪剖面的磁化率和>45μm粗颗粒含量变化曲线,并与格陵兰GRIP冰心和深海SPECMAP氧同位素曲线对比,讨论末次间冰期以来古季风特征及其相互关系。     

Impact of river network type on the time of concentration

Time of concentration (T _c) is one of the frequently used parameters to characterize the response of a drainage basin to a rainfall event. Conceptually, it is the time runoff travels from the hydraulically most distant location in a basin to its outlet. T _c was found to vary depending on river basin characteristics such as slope, soil infiltration, and flow path. In this study, we investigate if the drainage network type information can be used as an input to hydrological models, by estimating the time of concentration separately for different network types. Sixty-eight basins which have areas ranging from 24 to 965 km² in arid and non-arid regions of the USA are compared and the effect of climate is also analyzed. It is found that the slope of the linear relationship between T _c and the maximum hydraulic length of flow path shows different correlation coefficients ranging from 0.80 to 0.98 for different network types. It is observed that the slope of the regression line between T _c and the maximum hydraulic length of flow path is the lowest for dendritic networks (slope of 0.26), while pinnate networks have the steepest slope of the regression line (slope of 0.59). This indicates that the drainage network type has a direct impact on the hydrological behavior of the basin and can represent a direct input in hydrological modeling.     

Early Last Interglacial palaeoenvironments in the western Baltic Sea: benthic foraminiferal stable isotopes and diatom‐based sea‐surface salinity

Knudsen, K. L., Jiang, H., Kristensen, P., Gibbard, P. L. & Haila, H. 2011: Early Last Interglacial palaeoenvironments in the western Baltic Sea: benthic foraminiferal stable isotopes and diatom‐based sea‐surface salinity. Boreas, 10.1111/j.1502‐3885.2011.00206.x. ISSN 0300‐9483. Stable isotopes from benthic foraminifera, combined with diatom assemblage analysis and diatom‐based sea‐surface salinity reconstructions, are used for the interpretation of changes in bottom‐ and surface‐water conditions through the early Eemian at Ristinge Klint in the western Baltic Sea. Correlation of the sediments with the Eemian Stage is based on a previously published pollen analysis that indicates that they represent pollen zones E2–E5 and span ～3400 years. An initial brackish‐water phase, initiated c. 300 years after the beginning of the interglacial, is characterized by a rapid increase in sea‐surface and sea‐bottom salinity, followed by a major increase at c. 650 years, which is related to the opening of the Danish Straits to the western Baltic. The diatoms allow estimation of the maximum sea‐surface salinity in the time interval of c. 650–1250 years. After that, slightly reduced salinity is estimated for the interval of c. 1250–2600 years (with minimum values at c. 1600–2200 years). This may be related to a period of high precipitation/humidity and thus increased freshwater run‐off from land. Together with a continuous increase in the water depth, this may have contributed to the gradual development of a stratified water column after c. 1600 years. The stratification was, however, particularly pronounced between c. 2600 and 3400 years, a period with particularly high sea‐surface temperature, as well as bottom‐water salinity, and thus a maximum influence of Atlantic water masses. The freshwater run‐off from land may have been reduced as a result of particularly high summer temperatures during the climatic optimum.     

Water toxicity and metal contamination assessment of a polluted river: the Upper Vistula River (Poland)

In aquatic systems, the bioavailability of an element to microorganisms is greatly influenced by its chemical speciation. The goal of this work was to assess metal toxicity to a green algae (Pseudokirchneriella subcapitata) and a bacterium (Vibrio fisheri) as a function of size fractionation and chemical speciation (using the program MINTEQA2) in contaminated water of the Upper Vistula River. Water samples were collected at 1 reference site, 4 polluted sites and one polluted site on the Vistula's main tributary, the Przemsza River. Toxicity measurements were performed on unfiltered samples and, total dissolved (<1.2 μm), and truly dissolved (<1 kDa) fractions. Trace metal (Cd, Co, Cr, Cu, Mn, Pb, Zn) concentrations were measured in these samples and also in the colloidal fraction (1 kDa–1.2 μm). At the reference site, the low metal concentrations were in agreement with the absence of measurable toxicity. In the polluted section of the river, free metal concentrations were largely below the potential toxic levels for bacteria, which was in agreement with the absence of toxicity. Although Zn²⁺ was at potentially toxic-level concentrations in total dissolved and truly dissolved fractions in the polluted riverine section, toxicity for algae was observed, only in truly dissolved fractions from two stations. The absence of toxicity in most samples was related to metal association with particles and with low molecular weight ligands as well as the presence of organic ligands (phenol). The reason for toxic effects in two ultrafiltered samples is not clear, but may be related to the elimination of the colloidal organic fraction and thus the eradication of its protective effect occurring in natural samples.     

河网非恒定水沙数学模型研究

建立了能够适用于多种情况的河网非恒定流水沙数学模型。推导提出了河网泥沙方程组的分级解法,提出了适用于河网计算的汊点分沙模式,分析和对比了多种分沙模式的适用性,对河网区域中可蓄水汊点也提出了相应的处理办法。采用汉江杜家台分蓄洪区的资料作了模型的验证和应用。     

GIS网络分析技术在河流水污染追踪中的应用

在分析河流水环境系统特征的基础上,探讨了GIS网络分析技术在河流水污染追踪中的应用方法。主要内容包括数字化河系网络模型的建立、河流水环境数据库的建立与集成、河流水污染追踪应用的方法与步骤,并以汉江流域河系为例,进行了原型研究。     

末次间冰期以来洛川黄土天然剩磁记录的可靠性

地磁倒转和漂移不仅是研究地球动力学的重要手段之一,也能使地磁年代框架更加准确。通过对洛川黄土剖面L1、S1进行详细的岩石磁学、古地磁研究,结果表明:L1、S1中主要的载磁矿物是磁铁矿,但赤铁矿也可能携带稳定的特征剩磁;洛川黄土剖面能够记录Blake漂移,并发生于(123±2)ka。通过S1中1 092~1 240cm处6套平行样品的古地磁结果,表明洛川黄土难以记录Blake漂移的形态学特征;L1未记录到Mono Lake和Laschamp漂移,但是在175cm处识别出1次明显的地磁异常事件,年代约17.9ka。我们认为该地磁异常事件应为Hilina Pali/Tianchi漂移。此外,导致同一极性事件在不同地区记录产生差异的可能原因有中国黄土存在千年尺度的沉积间断、较低的沉积速率及黄土剖面所处地理位置的不同。同一剖面平行样品间地磁漂移形态学存在差异,可能是由于极性漂移期间较低的古地磁场强度抑制了黄土剩磁记录能力所致。     

Hydrogeological evolution of the Luni river basin,Rajasthan, western India: A review

The Luni river basin has been evolved as a result of typical hydrogeomorphic processes of arid zone, operating under the influence of active tectonic lineaments. A detailed analysis of stream morphology in relation to geology and lineaments carried out on selected windows indicated the morphological control of the streams while flowing over the lineaments from the eastern to the western part of the basin. Typical valley fills indicated by dark green tone on digitally processed images and the pediments showing greenish white tone appear in sharp contrast and indicate respectively the graben and horst structures. A detailed identification of lineaments for the georesources and geological evaluation has been carried out. Earlier analysis carried out on Bouguer anomalies correlate with graben and horst structures in the subsurface. Quaternary sequences have been dated from 80 ka to 3 ka indicating a range of fluvial to aeolian deposits reflecting prevailing climatic conditions. However, the changes in sediment type from coarse and mixed of all size grades to fine in a vertical litho-column warrant further studies on fine resolution stratigraphy and high resolution stratigraphy for understanding climatic variations in the region     

Evolution and demise of the Last Interglacial warmth in the subpolar North Atlantic

Detailed faunal, isotopic, and lithic marine records provide new insight into the stability and climate progression of the last interglacial period, Marine Isotope Stage (MIS) 5, which peaked approximately 125,000 years ago. In the eastern subpolar North Atlantic, at the latitude of Ireland, interglacial warmth of the ice volume minimum of substage 5e (MIS 5e) lasted 10,000 years (10 ka) and its demise occurred in two cooling steps. The first cooling step marked the end of the climatic optimum, which was 2–3 ka long. Minor ice rafting accompanied each cooling step; the second, larger, step encompassing cold events C26 and C25 was previously identified in the northwestern Atlantic. Approximately 4 °C of cooling occurred between peak interglacial warmth and C25, and the region experienced an additional temporary cooling of at least 1–2 °C during C24, a cooling event associated with widespread ice rafting in the North Atlantic. Beginning with C24, MIS 5 was characterized by oscillations of at least 1–2 °C superimposed on a generally cool baseline. The results of this study imply that the marine climatic optimum of the last interglacial was shorter than previously thought. The finding that the eastern subpolar North Atlantic cooled significantly before C24 reconciles terrestrial evidence for progressive climate deterioration at similar and lower latitudes with marine conditions. Our results also demonstrate a close association between modest ice rafting, cooling, and deep ocean circulation even during the peak of MIS 5e and in the earliest stages of ice growth.