N. Dobrotin, A. Bitinas, D. Michelevičius, A. Damušytė, J. Mažeika
One of the unique places in Europe in both environmental and cultural terms is the Curonian Spit – a massive sandy barrier separating the Curonian Lagoon from the Baltic Sea. Straddling both the Lithuanian and the Russian parts, the spit is included into the UNESCO list of cultural heritage monuments. From the geological point of view, it is still an “alive” environment dominated by aeolian deposits. With the help of modern geophysical and geochronological techniques (ground-penetrating radar [GPR] surveys, LIDAR data, and radiocarbon [14C] dating), detailed investigations of paleosols were carried out in the Dead (Grey) Dunes massif located between Juodkrante and Pervalka settlements on the Lithuanian half of the Curonian Spit. Several soil-forming generations (phases) during 5800–4500, 3900–3100, 2600–2400, and from 1900 calendar years BP until the present have been distinguished. GPR surveys enabled a series of paleogeographic reconstructions of the massif for different time intervals of its evolutionary history.
{"title":"Reconstruction of the Dead (Grey) Dune evolution along the Curonian Spit, Southeastern Baltic","authors":"N. Dobrotin, A. Bitinas, D. Michelevičius, A. Damušytė, J. Mažeika","doi":"10.17741/BGSF/85.1.004","DOIUrl":"https://doi.org/10.17741/BGSF/85.1.004","url":null,"abstract":"One of the unique places in Europe in both environmental and cultural terms is the Curonian Spit – a massive sandy barrier separating the Curonian Lagoon from the Baltic Sea. Straddling both the Lithuanian and the Russian parts, the spit is included into the UNESCO list of cultural heritage monuments. From the geological point of view, it is still an “alive” environment dominated by aeolian deposits. With the help of modern geophysical and geochronological techniques (ground-penetrating radar [GPR] surveys, LIDAR data, and radiocarbon [14C] dating), detailed investigations of paleosols were carried out in the Dead (Grey) Dunes massif located between Juodkrante and Pervalka settlements on the Lithuanian half of the Curonian Spit. Several soil-forming generations (phases) during 5800–4500, 3900–3100, 2600–2400, and from 1900 calendar years BP until the present have been distinguished. GPR surveys enabled a series of paleogeographic reconstructions of the massif for different time intervals of its evolutionary history.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2013-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Petäjäskoski Formation, a new lithostratigraphic unit in the Paleoproterozoic Peräpohja Belt, northern Finland","authors":"Markus Kyläkoski, E. Hanski, H. Huhma","doi":"10.17741/BGSF/84.2.001","DOIUrl":"https://doi.org/10.17741/BGSF/84.2.001","url":null,"abstract":"","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The southern Finnish Lapland area in the central part of the Fennoscandian shield is a geologically complex zone comprising several Archean blocks and Paleoproterozoic supracrustal belts all of which are intruded by voluminous Paleoproterozoic granites (the central Lapland granitoid complex, CLGC). New in-situ single crystal zircon U–Pb age determinations coupled with Lu–Hf isotope data from the same zircons were acquired from five granitoid rocks and one amphibolitic rock sample from the southern Lapland area. The samples represent at least four distinct magmatic events (at ca. 2.77 Ga, 2.12 Ga, 1.81 Ga, and 1.76 Ga). The 2.77 Ga and the 1.81-1.76 Ga events have initial Hf isotope signatures implying that local Archean rocks represent the source for the younger granites. The 2.12 Ga event has a slightly more juvenile Hf isotope composition suggesting either that the source for the 2.12 Ga granites represents a different Archean block or that the source is composed of mixed Archean and Paleoproterozoic components. The Neoarchean source for the Paleoproterozoic granites may be traced through the CLGC all the way to the Jokkmokk area in Sweden and possibly to the Lofoten area in Norway.
{"title":"Temporal and Hf isotope geochemical evolution of southern Finnish Lapland from 2.77 Ga to 1.76 Ga","authors":"L. Lauri, T. Andersen, J. Räsänen, H. Juopperi","doi":"10.17741/BGSF/84.2.002","DOIUrl":"https://doi.org/10.17741/BGSF/84.2.002","url":null,"abstract":"The southern Finnish Lapland area in the central part of the Fennoscandian shield is a geologically complex zone comprising several Archean blocks and Paleoproterozoic supracrustal belts all of which are intruded by voluminous Paleoproterozoic granites (the central Lapland granitoid complex, CLGC). New in-situ single crystal zircon U–Pb age determinations coupled with Lu–Hf isotope data from the same zircons were acquired from five granitoid rocks and one amphibolitic rock sample from the southern Lapland area. The samples represent at least four distinct magmatic events (at ca. 2.77 Ga, 2.12 Ga, 1.81 Ga, and 1.76 Ga). The 2.77 Ga and the 1.81-1.76 Ga events have initial Hf isotope signatures implying that local Archean rocks represent the source for the younger granites. The 2.12 Ga event has a slightly more juvenile Hf isotope composition suggesting either that the source for the 2.12 Ga granites represents a different Archean block or that the source is composed of mixed Archean and Paleoproterozoic components. The Neoarchean source for the Paleoproterozoic granites may be traced through the CLGC all the way to the Jokkmokk area in Sweden and possibly to the Lofoten area in Norway.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Natural stone deposits in an assemblage of subhorizontal intrusions - The Kuru granite batholith","authors":"O. Selonen, C. Ehlers, P. Härmä, R. Nyman","doi":"10.17741/BGSF/84.2.004","DOIUrl":"https://doi.org/10.17741/BGSF/84.2.004","url":null,"abstract":"","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2012-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Preglacial geomorphology of the northern Baltic Lowland and the Valdai Hills, north-western Russia","authors":"A. Y. Krotova-Putintseva, V. R. Verbitskiy","doi":"10.17741/BGSF/84.1.005","DOIUrl":"https://doi.org/10.17741/BGSF/84.1.005","url":null,"abstract":"","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Saarse, A. Heinsalu, S. Veski, L. Amon, Andrejus Gaidamavičius
This paper presents new bio-, litho- and chronostratigraphical evidence from two adjacent sediment sequences of the Todva and Saku basins, northern Estonia that refine the age estimate of the Palivere ice-marginal zone and the deglaciation history of Estonia. Previous palynological studies demonstrated the presence of late-glacial sediments in the area; however, those sections were not dated, and their ages were poorly constrained. New accelerator mass spectrometry (AMS) 14 C dates show that sedimentation in the Todva basin started at approximately 13 200 cal yr BP. Therefore, because the studied sites are located at the distal part of this zone, we infer that this age represents the minimum timing of the ice retreat from the Palivere ice-marginal zone.
{"title":"On the deglaciation chronology of the Palivere ice-marginal zone, northern Estonia","authors":"L. Saarse, A. Heinsalu, S. Veski, L. Amon, Andrejus Gaidamavičius","doi":"10.17741/BGSF/84.1.002","DOIUrl":"https://doi.org/10.17741/BGSF/84.1.002","url":null,"abstract":"This paper presents new bio-, litho- and chronostratigraphical evidence from two adjacent sediment sequences of the Todva and Saku basins, northern Estonia that refine the age estimate of the Palivere ice-marginal zone and the deglaciation history of Estonia. Previous palynological studies demonstrated the presence of late-glacial sediments in the area; however, those sections were not dated, and their ages were poorly constrained. New accelerator mass spectrometry (AMS) 14 C dates show that sedimentation in the Todva basin started at approximately 13 200 cal yr BP. Therefore, because the studied sites are located at the distal part of this zone, we infer that this age represents the minimum timing of the ice retreat from the Palivere ice-marginal zone.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bulletin of the Geological Society of Finland, Vol. 84, 2012, pp 45–57 This paper presents new results on the morphometry and spatial distribution of the glaciogenic landforms and ice flow directions in the Madliena Tilted Plain that occupies the eastern part of the Central Latvian Lowland. Landforms were investigated by using topographic maps at scales of 1:25 000 and 1:10 000. There were identified and mapped 1461 glaciogenic landforms such as drumlins, end moraine ridges, eskers, ribbed moraines, marginal ridges, lateral shear margin moraines and recessional formations. Particular attention is given to the morphometry, spatial distribution, and the internal structure of drumlins. Glacial landscape of the study area was formed by the Zemgale ice lobe in course of deglaciation of the Late Weichselian Fennoscandian Ice Sheet, when the ice decay was interrupted by the reactivation of the Middle Lithuanian and the North Lithuanian glacial phases at the end of the Oldest Dryas (18–15 ka BP). The detailed study of the internal structure of the Brenceni drumlin suggests that it consists of glaciotectonically disturbed glacio-aquatic sediments and of a single till thrust sheet between sand sediments on the flank of the drumlin. Morphometric analysis of the drumlin field shows that the mean length of drumlins is about 850 m; the mean width indicates the average size 280 m, and the mean elongation ratio is 3.0. The obtained statistics compared to the morphometry of drumlins worldwide, show close similarity, so it coincides with the concept that in general morphometry of drumlins is mostly independent of their location and the characteristics of the ice streams.
{"title":"Drumlins and related glaciogenic landforms of the Madliena Tilted plain, Central Latvian Lowland","authors":"P. Sarala, K. Lamsters","doi":"10.17741/BGSF/84.1.004","DOIUrl":"https://doi.org/10.17741/BGSF/84.1.004","url":null,"abstract":"Bulletin of the Geological Society of Finland, Vol. 84, 2012, pp 45–57 This paper presents new results on the morphometry and spatial distribution of the glaciogenic landforms and ice flow directions in the Madliena Tilted Plain that occupies the eastern part of the Central Latvian Lowland. Landforms were investigated by using topographic maps at scales of 1:25 000 and 1:10 000. There were identified and mapped 1461 glaciogenic landforms such as drumlins, end moraine ridges, eskers, ribbed moraines, marginal ridges, lateral shear margin moraines and recessional formations. Particular attention is given to the morphometry, spatial distribution, and the internal structure of drumlins. Glacial landscape of the study area was formed by the Zemgale ice lobe in course of deglaciation of the Late Weichselian Fennoscandian Ice Sheet, when the ice decay was interrupted by the reactivation of the Middle Lithuanian and the North Lithuanian glacial phases at the end of the Oldest Dryas (18–15 ka BP). The detailed study of the internal structure of the Brenceni drumlin suggests that it consists of glaciotectonically disturbed glacio-aquatic sediments and of a single till thrust sheet between sand sediments on the flank of the drumlin. Morphometric analysis of the drumlin field shows that the mean length of drumlins is about 850 m; the mean width indicates the average size 280 m, and the mean elongation ratio is 3.0. The obtained statistics compared to the morphometry of drumlins worldwide, show close similarity, so it coincides with the concept that in general morphometry of drumlins is mostly independent of their location and the characteristics of the ice streams.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The distribution and varve thickness data of Late Weichselian varved clay were analyzed to describe the proglacial sedimentary environment, ice recession and water-level changes in the Baltic Ice Lake at the distal position of Pandivere–Neva (13.5–13.1 ka BP) icerecessional formations in western Estonia. According to vertical changes in natural water content, fabric and varve thickness, four clay units were distinguished, reflecting a change in the sedimentary environment from ice-proximal to distal conditions. The varved clay complex is locally interrupted by a massive silty-clay unit, interpreted as an icedrift material during the stagnation of the glacier margin at the Pandivere–Neva line. Varve correlation gave a 294-year-long floating varve chronology. According to total varve thickness and the relation between thicknesses of seasonal layers, an about 130year period of ice-proximal conditions in the study area was followed by a rapid (within ca 20 years) change to more distal conditions. The presented varve chronology does not cover the entire period of proglacial conditions in the area, as all studied clay sections displayed an erosional discontinuity at the upper contact. In total, ca 4 m of selective post-sedimentary erosion of clay is attributed to wave erosion due to a water-level drop after the final drainage of the Baltic Ice Lake. It is concluded that the Yoldia Sea minimum level in the Pärnu area was 0 to –2 m a.s.l.
分析了晚Weichselian期变粘土的分布和厚度资料，以描述爱沙尼亚西部Pandivere-Neva (13.5 ~ 13.1 ka BP)冰退地层远端波罗的海冰湖的前冰期沉积环境、冰退和水位变化。根据天然含水量、组构和阀厚的垂直变化，划分出4个粘土单元，反映了沉积环境从冰近端到远端条件的变化。破碎的粘土复合体在局部被一个巨大的粉质粘土单元打断，这被解释为pandiva - neva线冰川边缘停滞期间的冰漂物质。瓣膜相关性给出了294年的浮动瓣膜年表。根据总厚度和季节层厚度之间的关系，研究区冰-近端条件在约130年的周期后迅速(约20年)向远端条件转变。所提出的年代学并不能涵盖该地区前冰期的整个时期，因为所有研究的粘土剖面在上部接触处都显示出侵蚀不连续。总的来说，约4米的选择性沉积后粘土侵蚀可归因于波罗的海冰湖最终排水后水位下降造成的波浪侵蚀。推断Pärnu地区约迪亚海最低水位为0 ~ 2 m a.s.l。
{"title":"Glacial varves at the distal slope of Pandivere-Neva ice-recessional formations in western Estonia","authors":"P. Talviste, T. Hang, M. Kohv","doi":"10.17741/BGSF/84.1.001","DOIUrl":"https://doi.org/10.17741/BGSF/84.1.001","url":null,"abstract":"The distribution and varve thickness data of Late Weichselian varved clay were analyzed to describe the proglacial sedimentary environment, ice recession and water-level changes in the Baltic Ice Lake at the distal position of Pandivere–Neva (13.5–13.1 ka BP) icerecessional formations in western Estonia. According to vertical changes in natural water content, fabric and varve thickness, four clay units were distinguished, reflecting a change in the sedimentary environment from ice-proximal to distal conditions. The varved clay complex is locally interrupted by a massive silty-clay unit, interpreted as an icedrift material during the stagnation of the glacier margin at the Pandivere–Neva line. Varve correlation gave a 294-year-long floating varve chronology. According to total varve thickness and the relation between thicknesses of seasonal layers, an about 130year period of ice-proximal conditions in the study area was followed by a rapid (within ca 20 years) change to more distal conditions. The presented varve chronology does not cover the entire period of proglacial conditions in the area, as all studied clay sections displayed an erosional discontinuity at the upper contact. In total, ca 4 m of selective post-sedimentary erosion of clay is attributed to wave erosion due to a water-level drop after the final drainage of the Baltic Ice Lake. It is concluded that the Yoldia Sea minimum level in the Pärnu area was 0 to –2 m a.s.l.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The coversands distributed in the Blonie glaciolacustrine basin, west of Warsaw (Central Poland) were investigated. Textural features including grain size, rounding and frosting of quartz grains and mineralogical-petrographic composition in the sandy fractions (0.5– 0.8 and 0.8–1.0 mm) were examined and the types, dynamics, regime and variation in processes during the formation of the coversands were determined. The sands are characterized by the prevalence of quartz and lack of micaceous minerals. Moreover, the relatively high content of partially rounded, matt (EM/RM) and well-rounded (RM) quartz grains, typical of aeolian sedimentary conditions, was certified. Hence, the results show a high aeolization degree of the investigated sediments, thus correlating them with aeolian deposition in dry, periglacial conditions after drying up of the Warsaw icedammed lake.
{"title":"Geological setting and sedimentary characteristics of the coversands distributed in the western part of the Blonie glaciolacustrine basin (Central Poland) - preliminary results","authors":"E. Kalińska","doi":"10.17741/BGSF/84.1.003","DOIUrl":"https://doi.org/10.17741/BGSF/84.1.003","url":null,"abstract":"The coversands distributed in the Blonie glaciolacustrine basin, west of Warsaw (Central Poland) were investigated. Textural features including grain size, rounding and frosting of quartz grains and mineralogical-petrographic composition in the sandy fractions (0.5– 0.8 and 0.8–1.0 mm) were examined and the types, dynamics, regime and variation in processes during the formation of the coversands were determined. The sands are characterized by the prevalence of quartz and lack of micaceous minerals. Moreover, the relatively high content of partially rounded, matt (EM/RM) and well-rounded (RM) quartz grains, typical of aeolian sedimentary conditions, was certified. Hence, the results show a high aeolization degree of the investigated sediments, thus correlating them with aeolian deposition in dry, periglacial conditions after drying up of the Warsaw icedammed lake.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Geologic position of the Younger Dryas subfossil forest in the Warta River valley, central Poland","authors":"D. Dzieduszyńska, J. Petera-Zganiacz","doi":"10.17741/BGSF/84.1.006","DOIUrl":"https://doi.org/10.17741/BGSF/84.1.006","url":null,"abstract":"","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2012-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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