R. Hints, H. Huhma, V. Klein, M. Konsa, R. Kuldkepp, I. Mänttäri, V. Puura, A. Soesoo
{"title":"Svecofennian metamorphic zones in the basement of Estonia","authors":"R. Hints, H. Huhma, V. Klein, M. Konsa, R. Kuldkepp, I. Mänttäri, V. Puura, A. Soesoo","doi":"10.3176/geol.2004.3.04","DOIUrl":"https://doi.org/10.3176/geol.2004.3.04","url":null,"abstract":"","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"2016 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125720125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
. The aim of the present research was to reconstruct trends in the environmental changes and estimate the importance of the rapid change of δ 13 C in the Boreal as a stratigraphic marker by comprehensive study of stable carbon and oxygen isotopes and pollen from the lake marl section of Lake Ilmjärv (c. 2.5 ha closed lake situated in the Vooremaa drumlin area). The δ 13 C and the δ 18 O values reached their maxima near the end of the Boreal, then dropped and were practically constant up to the top of the marl sequence c. 3000 BP. These changes were accompanied by a remarkable improvement of climatic conditions and shifts in the vegetation
{"title":"Stable isotope and pollen stratigraphy in marl sediments from Lake Ilmjärv (central Estonia)","authors":"J. Punning, T. Koff, T. Martma, Göran Possnert","doi":"10.3176/geol.2002.3.04","DOIUrl":"https://doi.org/10.3176/geol.2002.3.04","url":null,"abstract":". The aim of the present research was to reconstruct trends in the environmental changes and estimate the importance of the rapid change of δ 13 C in the Boreal as a stratigraphic marker by comprehensive study of stable carbon and oxygen isotopes and pollen from the lake marl section of Lake Ilmjärv (c. 2.5 ha closed lake situated in the Vooremaa drumlin area). The δ 13 C and the δ 18 O values reached their maxima near the end of the Boreal, then dropped and were practically constant up to the top of the marl sequence c. 3000 BP. These changes were accompanied by a remarkable improvement of climatic conditions and shifts in the vegetation","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115790082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Localities with the actinopterygian Andreolepis in the northern part of Eurasia were revised. Andreolepis petri sp. nov. was established on the basis of distinct morphology and sculpture of the scales, and exoskeletal platelets in the Tabuska Beds, upper Ludlow or lower P idoli of the Ufa River section, the Central Urals. Andreolepis was excluded from the family Lophosteidae Gross, 1969 and placed into a new family Andreolepididae fam. nov.
修正了欧亚大陆北部有光翅类Andreolepis的地区。根据乌拉尔中部乌法河段上勒德洛河Tabuska河床和下P idoli河床的鳞片和外骨骼血小板的独特形态和雕刻，确定了Andreolepis petri sp11 .。从1969年开始，将andreolepidis从Lophosteidae Gross科中排除，并将其放入andreolepiddae fam中。11月。
{"title":"ANDREOLEPIS (ACTINOPTERYGII) IN THE UPPER SILURIAN OF NORTHERN EURASIA","authors":"T. Märss","doi":"10.3176/geol.2001.3.03","DOIUrl":"https://doi.org/10.3176/geol.2001.3.03","url":null,"abstract":"Localities with the actinopterygian Andreolepis in the northern part of Eurasia were revised. Andreolepis petri sp. nov. was established on the basis of distinct morphology and sculpture of the scales, and exoskeletal platelets in the Tabuska Beds, upper Ludlow or lower P idoli of the Ufa River section, the Central Urals. Andreolepis was excluded from the family Lophosteidae Gross, 1969 and placed into a new family Andreolepididae fam. nov.","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132136060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"PITKASOO – A WEST ESTONIAN HOLOCENE REFERENCE SITE","authors":"Lars-König Königsson, A. Poska","doi":"10.3176/geol.1998.4.03","DOIUrl":"https://doi.org/10.3176/geol.1998.4.03","url":null,"abstract":"","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"254 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134548011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
. Lake Võrtsjärv, with a surface area of 270 km 2 , has a very complicated geological history. Proglacial lakes of different shape and size were formed in the Võrtsjärv Lowland. Due to the tectonic uplift outflows to the west closed in the Early Holocene. At the beginning of the Middle Holocene, about 7500 BP, an outflow to the east developed and little by little the lake acquired its present contours. Like many lakes in Europe, Võrtsjärv has an open eastern (leeward) and a more swampy and overgrown western (windward) bank. The bottom sediments consist mostly of sapropel (gyttja), fine sand and silt. The sediments are thicker in the southern part of the elongated lake basin where the up to 9 m thick layer of sapropel is usually underlain by 8 m of lacustrine lime. Gradual rise of water level in the southern portion of the basin is caused by land uplift, the rate of which increases towards the northwest.
{"title":"Geological history of Lake Võrtsjärv","authors":"T. Moora, A. Raukas, E. Tavast","doi":"10.3176/geol.2002.3.03","DOIUrl":"https://doi.org/10.3176/geol.2002.3.03","url":null,"abstract":". Lake Võrtsjärv, with a surface area of 270 km 2 , has a very complicated geological history. Proglacial lakes of different shape and size were formed in the Võrtsjärv Lowland. Due to the tectonic uplift outflows to the west closed in the Early Holocene. At the beginning of the Middle Holocene, about 7500 BP, an outflow to the east developed and little by little the lake acquired its present contours. Like many lakes in Europe, Võrtsjärv has an open eastern (leeward) and a more swampy and overgrown western (windward) bank. The bottom sediments consist mostly of sapropel (gyttja), fine sand and silt. The sediments are thicker in the southern part of the elongated lake basin where the up to 9 m thick layer of sapropel is usually underlain by 8 m of lacustrine lime. Gradual rise of water level in the southern portion of the basin is caused by land uplift, the rate of which increases towards the northwest.","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133894919","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Precambrian basement of Estonia","authors":"A. Soesoo","doi":"10.3176/geol.2004.3.01","DOIUrl":"https://doi.org/10.3176/geol.2004.3.01","url":null,"abstract":"","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134051177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
exciting old idea of catastrophes (= events) in Earth history, (b) the idea is promising good practical applications for detailed correlation of sections, and (c) high level activity of the project. Speaking about catastrophes, one usually means (mass) extinction events, but innovation, radiation, etc. events are not less interesting. The Silurian was preceded by the well-known late Ordovician glaciation-triggered extinction (O/S Boundary Event) and followed by several events of different scale and origin within the Devonian (a major one, the so-called Kellwasser Event seems to be very instructive for Silurian students as a typical anoxic layer oscillation event with a complex of other factors; Walliser, 1986). In the Silurian A.J. Boucot (1990) Ilisted the following levels at which relatively minor bioevents occurred: Co—Cs boundary (late Llandovery) in the early Wenlock, the late Wenlock, the late Ludlow, and the Silurian-Devonian boundary. Until now these events have gained little attention, but the top Wenlock, the (undgreni event and the following leintwardinensis event were thoroughly described from the aspect of graptolite diversity changes by T. Koren (1987). The first level was earlier known also as the dubius-nassa Interregnum (Jaeger, 1976), which might be called also the nassa-ludensis crisis (Great Crisis H. Jaeger, oral comm.). Ranking of events is rather arbitrary, but exact definition of a level where something happens is important. Otherwise we cannot distinguish whether there was a “big” event or a series of minor ones. For example, when the late Wenlock or Wenlock-Ludlow Boundary or lundgreni event
{"title":"SILURIAN BIOEVENT STUDIES A PART OF THE IGCP PROJECT 216 “GLOBAL BIOLOGICAL EVENTS IN EARTH HISTORY”","authors":"D. Kaljo","doi":"10.3176/geol.1991.2.01","DOIUrl":"https://doi.org/10.3176/geol.1991.2.01","url":null,"abstract":"exciting old idea of catastrophes (= events) in Earth history, (b) the idea is promising good practical applications for detailed correlation of sections, and (c) high level activity of the project. Speaking about catastrophes, one usually means (mass) extinction events, but innovation, radiation, etc. events are not less interesting. The Silurian was preceded by the well-known late Ordovician glaciation-triggered extinction (O/S Boundary Event) and followed by several events of different scale and origin within the Devonian (a major one, the so-called Kellwasser Event seems to be very instructive for Silurian students as a typical anoxic layer oscillation event with a complex of other factors; Walliser, 1986). In the Silurian A.J. Boucot (1990) Ilisted the following levels at which relatively minor bioevents occurred: Co—Cs boundary (late Llandovery) in the early Wenlock, the late Wenlock, the late Ludlow, and the Silurian-Devonian boundary. Until now these events have gained little attention, but the top Wenlock, the (undgreni event and the following leintwardinensis event were thoroughly described from the aspect of graptolite diversity changes by T. Koren (1987). The first level was earlier known also as the dubius-nassa Interregnum (Jaeger, 1976), which might be called also the nassa-ludensis crisis (Great Crisis H. Jaeger, oral comm.). Ranking of events is rather arbitrary, but exact definition of a level where something happens is important. Otherwise we cannot distinguish whether there was a “big” event or a series of minor ones. For example, when the late Wenlock or Wenlock-Ludlow Boundary or lundgreni event","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131723987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Alexeyev, I. Chistyakova, V. Khasankayev, V. Kuleshov, Y. Lavrushin, Y. Spiridonova
{"title":"К ПАЛЕОМАРИНОЛОГИИ КЛИМАТИЧЕСКОГО ОПТИМУМА ГОЛОЦЕНА СЕВЕРО-ЗАПАДНОЙ ЧАСТИ БАРЕНЦЕВА МОРЯ","authors":"V. Alexeyev, I. Chistyakova, V. Khasankayev, V. Kuleshov, Y. Lavrushin, Y. Spiridonova","doi":"10.3176/geol.1990.2.05","DOIUrl":"https://doi.org/10.3176/geol.1990.2.05","url":null,"abstract":"","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131829857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Graptolitic argillite contains in addition to rockforming minerals (hydromicas, chlorite, clastic quartz of pelitic fraction) and accessory minerals also authigenic ones. Numerous clay minerals, carbonates, sulphides, and siliceous minerals are authigenic. Siliceous minerals form lenticular or pocket-shaped laminae on several levels in the eastern part of the distribution area of graptolitic argillite that contains spicules of siliceous sponges and siliceous dioxide. Siliceous dioxide occurs in various forms: as amorphous silicon, opal, chalcedony, and authigenic quartz. Opal may occur in the composition of spicules and partly also of globules. Chalcedony is found as aggregates with a fibrous composition and collomorphic structure. It forms spherulites, bundles, and incrustites around clastic grains and pyrite crystals and on the walls of cavities. There are metacolloidal pellets, plats, and rods of irregular shape among the chalcedonic globules. Edgings and coatings of authigenic quartz are abundant. The siliceous laminae were formed during the early phase of diagenesis. Amorphous silica dioxide was replaced by chalcedony and then by quartz during the diagenesis. Their formation became possible thanks 10 а short-term input of a large amount of silicecous material into the basin. The leaching of silica as colloidal solutions in the denudation area was not sufficient for this. It is supposed that hydrothermae were a source of silicon. The deep origin of silicon is supported by the high content of several typical hydrothermal elements in the siliceous interlayers.
{"title":"AUTHIGENIC SILICEOUS MINERALS IN THE TREMADOC GRAPTOLITIC ARGILLITE OF ESTONIA","authors":"A. Loog, V. Petersell","doi":"10.3176/geol.1995.1.03","DOIUrl":"https://doi.org/10.3176/geol.1995.1.03","url":null,"abstract":"Graptolitic argillite contains in addition to rockforming minerals (hydromicas, chlorite, clastic quartz of pelitic fraction) and accessory minerals also authigenic ones. Numerous clay minerals, carbonates, sulphides, and siliceous minerals are authigenic. Siliceous minerals form lenticular or pocket-shaped laminae on several levels in the eastern part of the distribution area of graptolitic argillite that contains spicules of siliceous sponges and siliceous dioxide. Siliceous dioxide occurs in various forms: as amorphous silicon, opal, chalcedony, and authigenic quartz. Opal may occur in the composition of spicules and partly also of globules. Chalcedony is found as aggregates with a fibrous composition and collomorphic structure. It forms spherulites, bundles, and incrustites around clastic grains and pyrite crystals and on the walls of cavities. There are metacolloidal pellets, plats, and rods of irregular shape among the chalcedonic globules. Edgings and coatings of authigenic quartz are abundant. The siliceous laminae were formed during the early phase of diagenesis. Amorphous silica dioxide was replaced by chalcedony and then by quartz during the diagenesis. Their formation became possible thanks 10 а short-term input of a large amount of silicecous material into the basin. The leaching of silica as colloidal solutions in the denudation area was not sufficient for this. It is supposed that hydrothermae were a source of silicon. The deep origin of silicon is supported by the high content of several typical hydrothermal elements in the siliceous interlayers.","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127558276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A NEW CONODONT FROM THE LOWER LLANDOVERY OF ESTONIA","authors":"P. Männik","doi":"10.3176/geol.1992.1.03","DOIUrl":"https://doi.org/10.3176/geol.1992.1.03","url":null,"abstract":"","PeriodicalId":237994,"journal":{"name":"Proceedings of the Estonian Academy of Sciences. Geology","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132785911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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