Assessment of paleo-recharge under the Fennoscandian Ice Sheet and its impact on regional groundwater flow in the northern Baltic Artesian Basin using a numerical model

The study investigates the mechanism of glacial meltwater recharge under the Fennosciandian Ice Sheet during the last glacial maximum (LGM) and its impact on regional groundwater flow in the northern Baltic Artesian Basin (BAB) in Estonia and Latvia. The current hypothesis is that a flow reversal occurred in the BAB due to subglacial recharge during the LGM. This hypothesis is supported by an extensive dataset of geochemical and isotopic measurements in the groundwater of northern Estonia, exhibiting significant depletion in δ¹⁸O with respect to modern precipitation. To verify the consistency of this hypothesis and better understand groundwater flow dynamics during the LGM period, a numerical model is developed for this area. Two cross-sectional models have been created across the northern BAB, in which groundwater flow and the transport of δ¹⁸O have been simulated from the beginning of the LGM to present-day. Several simulations were performed with different subglacial boundary conditions, to investigate the uncertainty related to subglacial recharge of meltwater during the LGM and the subsequent flow reversal in the northern BAB. Several simulations provide a satisfying fit between computed and observed values of δ¹⁸O, which means that the hypothesis of subglacial recharge of meltwater is consistent with δ¹⁸O distribution. The numerical model suggests that preservation of meltwater in northern Estonia is controlled by confining layers and the proximity to the outcrop area of aquifers, located in the Gulf of Finland. The results also suggest that glacial meltwater has been preserved under the Baltic Sea in the Gulf of Riga.     

Physical geography in Estonia: Bridging western and eastern schools of landscape synthesis

This paper is an overview of principal investigations in the complex physical geography of Estonia. The focus is on landscape and regional studies, rather than geomorphology or hydrology.Academic geography in Estonia developed in the context of geographic exploration. In the 19th century a leading role among Russian explorers was played by the Baltic Germans Krusenstern, Bellingshausen, Middendorff, Wrangel, and others. After Estonia gained independence in 1919, well-known geographers from Northern (Granö) and Central (Haltenberger) Europe helped to develop landscape studies, which, led by Tammekann, Markus, and Kant, reached a considerable level of excellence by the 1930s. Due to the mass flight of intellectuals to the West during the 1940s, geography in particular sustained heavy losses. A network of state institutes was established when Estonia became an SSR. Even though geography was not among them, some of the institutes did deal with such spatial issues as natural resources and nature protection. During the seventies there was a broadening of research frontiers in physical geography. Various directions were developed in landscape morphology, geochemistry, geophysics, and ecology, parallel to similar developments in the USSR. Today activities are dominated by international cooperation among specialists from the Baltic Sea countries. Investigations have strong interdisciplinary character.     

Groundwater quality and its monitoring in the Baltic States

In the Baltic countries — Estonia, Latvia and Lithuania — groundwater is the principal and only source of clean drinking water. Its safe yield is rather large — 6.7 mln m³/d. At present, consumption does not reach half of this amount. Therefore, the resources available will be sufficient for a rather remote future, provided that groundwater is not polluted. Under Soviet rule, insufficient attention was paid to ecological problems in the Baltic States. As a result, due to constantly increasing surface pollution, groundwater quality is decreasing. The topmost, unconfined aquifer is unfit for use, especially in many urbanized areas. Moreover, pollutants, especially organics, are starting to enter the lower, artesian aquifers. To determine and forecast groundwater quality, a monitoring system has been worked out. However, in order to protect groundwater, besides monitoring, new laws, regulations, and guarantees for their implementation are necessary.     

A Middle Ordovician crinoid from the beach gravels of Ristna Cape,Hiiumaa Island,Estonia

Reworked fossils may be exotic, but more typically are locally derived. Echinoderms have only rarely been identified from beach clasts; most commonly, these are Upper Cretaceous echinoids from the Chalk. A pebble collected from a beach in Estonia has yielded a moderately well preserved specimen of the crinoid stem, Baltocrinus (col.) antiquus (Eichwald). This species is typical of the Baltic region, only being known from the Middle Ordovician (Darriwilian) of Estonia, but is exotic because the local outcrop is Upper Ordovician to Silurian.     

Development of the Baltic Ice Lake in the eastern Baltic

A GIS-based palaeogeographic reconstruction of the development of the Baltic Ice Lake (BIL) in the eastern Baltic during the deglaciation of the Scandinavian Ice Sheet is presented. A Late Glacial shoreline database containing more than 1000 sites from Finland, NW Russia, Estonia, Latvia and modern digital terrain models were used for palaeoreconstructions. The BIL occupied five different levels, represented by 492 shoreline features. The study shows that at about 13.3 cal. ka BP the BIL extended to the ice-free areas of Latvia, Estonia and NW Russia, represented by the highest shoreline in this region. Reconstructions demonstrate that BIL initially had the same water level as the Glacial Lakes Peipsi and Võrtsjärv, because these water bodies were connected via strait systems in central Estonia. These strait systems were closed at about 12.8–11.7 cal. ka BP prior to the final drainage of the BIL due to isostatic uplift. Glacial Lake Võrtsjärv was isolated from the BIL at about 12.4–12.0 cal. ka BP. Exact timing of Glacial Lake Peipsi isolation is not clear, but according to the altitude of the threshold in northeast Estonia and shore displacement data it was completed at about 12.4–11.7 cal. ka BP.     

Palaeogeographic reconstruction of proglacial lakes in Estonia

This paper describes a Geographical Information System (GIS)-based palaeogeographic reconstruction of the development of proglacial lakes formed during deglaciation in Estonia, and examines their common features and relations with the Baltic Ice Lake. Ice marginal positions, interpolated proglacial lake water levels and a digital terrain model were used to reconstruct the spatial distribution and bathymetry of the proglacial lakes. Our results suggest that the proglacial lakes formed a bay of the Baltic Ice Lake after the halt at the Pandivere-Neva ice margin about 13.3 cal. kyr BP. Shoreline reconstruction suggests that two major proglacial lake systems, one in eastern and the other in western Estonia, were connected via a strait and thus had identical water levels. The water budget calculations show that the strait was able to transfer a water volume several times greater than the melting glacier could produce. As this strait compensated for the water level difference between the two lake parts, the subsequent further merging in north Estonia did not result in catastrophic drainage, as has been proposed.     

青藏高原东部表土磁化率特征与环境意义

现代表土磁化率与气候因子关系的研究是黄土古气候重建的重要内容,在黄土高原地区取得了重要进展,但在青藏高原地区相对不足。在青藏高原东部系统采集了106个表土样品,分析了其磁化率的变化特征;并通过表土磁化率与气候因子的相关分析,讨论了气候因子对高原东部现代表土低频磁化率和频率磁化率的影响。结果表明：研究区表土磁化率特征主要受到温度和降水量的影响,水热组合差异影响表土磁化率值的高低。低频磁化率与气候因子的相关性较弱,总体上与温度的相关性优于降水量,可能表明其与气候因子的关系比较复杂;频率磁化率百分比与降水呈较好的正相关关系,表明该指标对降水量的变化更为敏感,可以用于青藏高原东部的古降水定量重建。     

The Baltic-Kattegat-Skagerrak estuarine system

Measurements of alkalinities and calcium concentrations in the Baltic Sea indicate that there has been a slight increase in both these parameters over the last century. These increases may have been caused by the leaching of limestone by acid rain. About ten percent of the nutrients are exported from the Baltic to the Kattegat; however, very little, if any, alkalinity is stored in the Baltic since river input and system output are approximately equal. Since the precipitation and evaporation are almost equal in the Baltic Sea, corrections are not needed for river inputs.     

耕层土壤含水量消长规律分析

利用濉溪县耕层土壤含水量和同期观测的降水量、蒸发量资料分析表明:耕层土壤含水量的消长与基期土壤含水量、期间降水量和蒸发量呈多元直线相关关系,其中耕层土壤含水量增加量主要取决于基期土壤含水量的高低和降水量的多少;土壤含水量减少量主要取决于蒸发量的多少和基期土壤含水量的高低。耕层土壤相对含水量在50%～65%之间,需降水或补充灌溉15.9～82.3mm的水量。降水效力与基期土壤含水量和降水量呈多元指数曲线关系,蒸发效力与基期土壤含水量呈指数曲线关系。耕层土壤含水量的消退呈“快—缓慢—滞缓”的变化过程。使耕层相对含水量达到80%以上的一次降水(过程)过后,连续9.2～39.6d无降水耕层相对含水量尚可维持在60%以上。     

The geology of the southeastern Baltic Sea: a review

The Baltic Sea, particularly its southeastern part, is discussed in the paper. Investigations of regional character as well as specialized studies in the area are reviewed. General historical works are mentioned briefly. Previous surveys since the 1950s are presented by the subject studied. The compilation of geological structure of the SE Baltic Sea bottom and adjacent land of Balticum (Baltic States: Estonia, Latvia, Lithuania) is based on considerable amounts of summarized materials. The crystalline basement, sedimentary cover and Quaternary deposits are characterized in the comprehensive survey of geological structure. From a stratigraphical point of view, geological sequence of the platformal cover is comparatively complete: deposits of all geological systems (from the Archean to Cenozoic) are present in the Baltic Syneclise. Considering geotectonical cycles, the sedimentary cover of the syneclise is subdivided into four structural complexes. The thickness and distribution of Quaternary deposits are closely related to the recent bottom relief of the Baltic Sea that in turn is inherited from the Pre-Quaternary surface. Buried palaeo-valleys are characteristic of the Pre-Quaternary surface in the Baltic region and the Baltic Sea bottom. The Quaternary is characterized by layers of various geneses and by sharp changes of their thicknesses.     

A mass balance approach to estimate the dilution and removal of the pollutants in stream water polluted by acid mine drainage

 A few simple mass balance equations were developed to simultaneously estimate how much the pollutants from acid mine drainage (AMD) in stream water are diluted and removed during their migration. The application of the equations requires knowledge of the variations in the concentrations of the dissolved pollutants and the stoichiometry of the precipitation reaction of the pollutants when none of the pollutant shows a conservative behavior along the stream path. The calculation should be restricted to the pollutants showing much higher concentrations in the polluted main stream water than in the combining or diluting water of the same target area. The mass balance equations were applied to estimate the dilution factor and precipitation fractions of pollutants in Imgok Creek such as Fe, SO₄ and Al from the AMD of Yeongdong mine. The results show that the estimation, especially for SO₄ and Al, significantly depends on the kinds of the precipitates. When FeOHSO₄ and AlOHSO₄ are assumed to precipitate, the maximum removal fractions of SO₄ and Al by precipitation are respectively 34% and 46% of the original input, which is much higher than the values estimated when SO₄ is considered to be perfectly conservative. It indicates that the stoichiometry of precipitation reaction is very important in the interpretation of the pollutant dilution and migration and assessment of environmental impacts of AMD. The applicability of the mass balance equations may still need to be verified. However, examining the calculated dilution factor and precipitation fractions with the equations can provide invaluable information on not only the behavior but also unexpected input of the pollutants in the stream water polluted by AMD and other point sources. Received: 12 November 1997 · Accepted: 30 March 1998     

Contribution of regional climate drivers to future winter sea-level changes in the Baltic Sea estimated by statistical methods and simulations of climate models

A statistical downscaling approach is applied to the output of five different global climate model simulations driven by twenty-first century future scenarios of greenhouse gas concentrations. The contribution of sea-level pressure (SLP) and precipitation changes to regional future winter sea-level changes is estimated for four Baltic sea-level stations by establishing statistical relationships between sea level as predictand and large-scale climate fields as predictors. Using SLP as predictor for the central and eastern Baltic Sea level stations, three climate models lead to statistically significant twenty-first century future trends in the range of the order of 1–2 mm/year. Using precipitation as predictor for the stations in the southern Baltic coast all five models lead to statistically significant trends with a range of the order of 0.4 mm/year. These numbers are smaller, but of the order of magnitude as the predicted global sea-level rise.     

History of the reindeer (Rangifer tarandus) in the eastern Baltic region and its implications for the origin and immigration routes of the recent northern European wild reindeer populations

A total of 45 subfossil reindeer (Rangifer tarandus) antlers and bones - artefacts excluded - have been found over the years in the Baltic countries of Estonia, Latvia and Lithuania. The relatively high number of specimens suggests a stable residence of the species in the eastern Baltic region. For the first time, 12 of these finds were radiocarbon-dated. The ages of the samples range between 12 085 and 9970 ¹⁴C yr BP (14 180-11 280 cal. yr BP), and cover the Lateglacial and early Holocene, a time period during which climatic conditions shifted from periglacial to temperate. The dates suggest a rapid colonization of the area during the deglaciation period and a local extinction around the Pleistocene-Holocene boundary. The results of the study do not support the theory that the recent wild reindeer populations of northern Europe had their origin in the Late Weichselian reindeer populations of the eastern Baltic region.     

First discovery of cryptotephra in Holocene peat deposits of Estonia, eastern Baltic

This article reports the first discovery of middle Holocene cryptotephra from a peat sequence in Estonia, eastern Baltic. Two sequences, Mustjärve and Parika (located 110 km apart), were chosen for a pilot study aimed at finding traces of tephra fallout during the middle Holocene. Peat accumulation at both sites started in the early Holocene (c. 9500–9000 ¹⁴C yr BP; c . 11 000–10000 cal. yr BP) and continued throughout the whole Holocene. The radiocarbon-dated intervals between c. 2000 and 5000 ¹⁴C yr BP (c. 2000–5500 cal. yr BP) were chosen from both sites for the study. Colourless tephra shards were identified at 312–316 cm below the peat surface in the Mustjärve peat sequence, while no tephra was found in peat of the same age at Parika. Electron microprobe analyses suggest a correlation with the initial phase of the Hekla-4 eruption (c. 4260 cal. yr BP), although the age-depth model indicated an age around 4900 cal. yr BP. Small concentrations of colourless to light brown tephra shards at 266–270 cm in the Mustjärve sequence indicate that the Kebister tephra (c. 3750 cal. yr BP) might also be present, but geochemical analyses were not possible. The low concentration and small size of the tephra particles indicate that Estonian bogs are probably on the verge of where tephrochronology is possible in northwestern Europe. Further studies of full Holocene sequences are required in order to discover traces of other ash plumes reaching as far east as the eastern Baltic area.     

Depth and controls of Ca-rhodochrosite precipitation in bioturbated sediments of the Eastern Equatorial Pacific, ODP Leg 201, Site 1226 and DSDP Leg 68, Site 503

The occurrence of early diagenetic Ca‐rhodochrosite [(Mn,Ca)CO₃] is reported in association with ‘griotte’‐type nodular limestones from basinal settings in the geological record; however, without the comparison of analogous modern examples, the controls on precipitation remain speculative. Here the findings of four layers of primary Ca‐rich rhodochrosite recovered from a modern deep‐sea setting in the Eastern Equatorial Pacific, from bioturbated sediments 300 m below sea floor, are reported (Ocean Drilling Program, Leg 201, Site 1226). The mineralogy is similar to cements in burrows recovered during Deep Sea Drilling Project Leg 68 at Eastern Equatorial Pacific Site 503 and from Ca‐rhodochrosite laminae in sediments of the central Baltic Sea. Petrographic relationships and constant oxygen isotopic compositions in the Ca‐rhodochrosite around 5‰ at all depths indicate a shallow burial depth of formation. The onset of 1‰ heavier oxygen isotope composition of Ca‐rhodochrosite at Site 503, about 30 m below the Pliocene/Pleistocene boundary, further suggests that precipitation occurs in the range of 30 m below sea floor. The approximate depth of formation allowed an approximate empirical fractionation factor for marine Ca‐rhodochrosite to be constrained that strongly differs from previously published theoretical values. Based on the approximate precipitation depth, authigenic Ca‐rhodochrosite forms within the SO₄^2?‐reduction zone. Moderately negative δ¹³C values (around ?3‰) and total organic carbon lower than 2 wt% indicate a relatively low contribution of CO₃^2? from organic C mineralization within the expanded redox zonation in the Eastern Equatorial Pacific. It is suggested that the alkalinity is increased by a rise in pH at focused sites of Mn‐reduction coupled with S^2? oxidation. High concentrations of Mn‐oxide can accumulate in layers or burrows because of Mn‐cycling in suboxic sediments as suggested for the Baltic Sea Ca‐rhodochrosites. This study demonstrates how early diagenetic precipitates document biogeochemical processes from past diagenetic systems.     

Maps and mapping in Estonia

Estonia may be taken as an example of how cartography has developed in the national languages of the Baltic States. Late in the 17th century the first survey of Estonian and Latvian territories was carried out by the Swedes. Masterpieces of the 18th century and the first half of the 19th century are the Atlas of Livonia by L. A. Mellin and a special map of Livonia by C. G. Rücker. The first maps in Estonian appeared more than one hundred years ago. The short period of independence, 1918–1940, was one of rapid development in cartography, interrupted by occupation of the Baltic States by the USSR. Maps were destroyed or declared secret; use of maps was limited. From the beginning of the 1990s, a rapid renaissance of national cartography began.     

Stratigraphy of lake and bog deposits and climatic changes in the late-glacial and Holocene in the Soviet Baltic Republics: a review

Kabailiene, Meilute & Raukas, Anto 1987 06 01: Stratigraphy of lake and bog deposits and climatic changes in the late-glacial and Holocene in the Soviet Baltic Republics: a review. Boreas , Vol. 16, pp. 125–131. Oslo. ISSN 0300–9483.
The study of lake and bog deposits in the Soviet Baltic countries has long traditions. These areas are the most intensively studied in the U.S.S.R. The thickness of late-glacial and Holocene sediments reaches up to 38.5 m. The sections are represented most completely in the southern part of the study area, i.e. in Lithuania, whereas in North Estonia the accumulation of lake deposits started in Alleröd and the formation of peat only in pre-Boreal times. Alleröd deposits differ in their amount of organic remains and are everywhere considered as a reference horizon. In general, the accumulation of lake deposits and inferred climatic changes agree with those in adjoining areas. However, in detail they show important differences. Rather prominent differences are observed not only between North, Central and South Baltic, but also between elevated and lowland areas. Their elucidation requires the compilation of numerous local stratigraphic schemes.     

Environmental Geochemistry of Mining Activities in Panzhihua Region, Southwestern China

INTRODUCTIONMining activlties have significant envi ronmenta1 inll)ac'l ssuch as visual intrusions, dust, noise, blasting, trafflc and h}'drology (Kwolek, l999; Ripley et al., l996 ). The l)rot'csst'sof mineral extraction, processing, smelting and refinlng;1rt'never approximate to the environmental neutrality, but tht' affected areas can be ameliorated (KwoIek, l999; Klukanov;1;llltlRapant, 1999). The regions, where mining activities are I,r('sent or continuous for a long tlme, are pote…     

Pleistocene glacial deposits along the eastern periphery of the Scandinavian ice sheets - an overview

The Quaternary glacial sequences in the Baltic region in Estonia. Latvia and Lithuania are relatively complete and reasonably well studied. The maximum thickness of deposits (200 300 m) is found in the uplands and ancient valleys. Tills of several genetic types have been described and in this paper the present view on the structure of the Pleistocene cover is given. The ice movement and glacial sedimentation were controlled by climate. underlying topography and tectonic processes.     

中国东部表层土壤磁化率特征及其指示意义

磁化率是环境磁学研究中较常用、较易获得的指标之一,但其解释和意义又最为复杂.对采自中国东部从北到南涵盖中国主要气候带的风化-成壤成因的79个表层土壤样品进行高、低频磁化率和非磁滞剩磁测试并分析其与降水量、年均温等气候参数的关系.结果表明:(1)发育于不同类型母岩的风化-成壤成因表层土壤磁学性质之间存在显著差异,各磁化率参数与气候条件参数之间的关系大不一样,在大空间尺度进行磁学与气候条件的关系研究时,必须充分考虑地质背景与母岩类型的差异.(2)发育于花岗岩的表层土壤非磁滞剩磁磁化率与年降水量和年均温间呈显著负相关关系;而发育于玄武岩的表层土壤非磁滞剩磁磁化率与年降水量呈显著正相关关系.被广泛认可的黄土-古土壤序列磁化率与成壤的关系不一定适用于大空间尺度的其他气候区域.(3)在风化-成壤过程中,磁性颗粒有变细的趋势,但降水强度增大时,一些超细颗粒较易被搬运离开原地,单一磁学参数结果难以反映气候条件及环境变化.(4)风化-成壤成因表层土壤非磁滞剩磁磁化率能较好地反映风化成因土壤的风化程度,但风化-成壤表层土壤磁学性质变化的机制特别是对相应土壤剖面的磁性矿物迁移转化有待深入研究.