A. Barkov, A. A. Nikiforov, T. Halkoaho, J. Konnunaho
We document a new and unusual occurrence of patterns of protruding spheroidal weathering developed in a dunitic rock of the Pados-Tundra mafic-ultramafic complex of Early Proterozoic age, Kola Peninsula, Russia. It provides an example similar to that reported recently from a mineralized harzburgite in the Monchepluton layered complex in the same region. These patterns are genetically different from common results of “normal spheroidal weathering” sensu stricto. The spheroidally weathered dunite at Pados-Tundra consists of a high-Fo olivine, Ol (Fo87.5), which is, in fact, not altered. Accessory grains of aluminous chromite are present. Relief spheroids (1.5 to 4 cm in diameter; up to ~5 vol. %) are distributed sparsely and heterogeneously. They are hosted by the olivine matrix and composed of talc, Tlc, and tremolite, Tr, (Mg# = 95-96) formed presumably at the expense of orthopyroxene, Opx, (i.e., pre-existing oikocrysts) during a deuteric (autometasomatic) alteration. In contrast, oikocrystic Opx (En86.0) is quite fresh in related spheroids at Monchepluton, in which only minor deuteric alteration (Tlc + Tr) are observed. We infer that (1) the ball-shaped morphology of the weathered surface is a reflection of the presence of oikocrysts of Opx, which crystallized after Ol at the magmatic stage; they were entirely replaced by the deuterically induced Tlc + Tr at Pados-Tundra. (2) Differential rates of weathering are implied for rock-forming minerals in these ultramafic rocks, with a higher resistance of Opx vs. Fo-rich Ol, and Tlc + Tr vs. Fo-rich Ol. (3) The ball-like shape of the large spheroids, produced by magmatic processes, may likely represent an additional factor of their higher stability to weathering in the superficial environment. Similar patterns can be expected in other mafic-ultramafic complexes, especially in layered intrusions.
{"title":"The origin of spheroidal patterns of weathering in the Pados-Tundra mafic-ultramafic complex, Kola Peninsula, Russia","authors":"A. Barkov, A. A. Nikiforov, T. Halkoaho, J. Konnunaho","doi":"10.17741/BGSF/88.2.004","DOIUrl":"https://doi.org/10.17741/BGSF/88.2.004","url":null,"abstract":"We document a new and unusual occurrence of patterns of protruding spheroidal weathering developed in a dunitic rock of the Pados-Tundra mafic-ultramafic complex of Early Proterozoic age, Kola Peninsula, Russia. It provides an example similar to that reported recently from a mineralized harzburgite in the Monchepluton layered complex in the same region. These patterns are genetically different from common results of “normal spheroidal weathering” sensu stricto. The spheroidally weathered dunite at Pados-Tundra consists of a high-Fo olivine, Ol (Fo87.5), which is, in fact, not altered. Accessory grains of aluminous chromite are present. Relief spheroids (1.5 to 4 cm in diameter; up to ~5 vol. %) are distributed sparsely and heterogeneously. They are hosted by the olivine matrix and composed of talc, Tlc, and tremolite, Tr, (Mg# = 95-96) formed presumably at the expense of orthopyroxene, Opx, (i.e., pre-existing oikocrysts) during a deuteric (autometasomatic) alteration. In contrast, oikocrystic Opx (En86.0) is quite fresh in related spheroids at Monchepluton, in which only minor deuteric alteration (Tlc + Tr) are observed. We infer that (1) the ball-shaped morphology of the weathered surface is a reflection of the presence of oikocrysts of Opx, which crystallized after Ol at the magmatic stage; they were entirely replaced by the deuterically induced Tlc + Tr at Pados-Tundra. (2) Differential rates of weathering are implied for rock-forming minerals in these ultramafic rocks, with a higher resistance of Opx vs. Fo-rich Ol, and Tlc + Tr vs. Fo-rich Ol. (3) The ball-like shape of the large spheroids, produced by magmatic processes, may likely represent an additional factor of their higher stability to weathering in the superficial environment. Similar patterns can be expected in other mafic-ultramafic complexes, especially in layered intrusions.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"88 1","pages":"105-113"},"PeriodicalIF":0.7,"publicationDate":"2016-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67631616","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}
Pub Date : 2016-12-01DOI: 10.1044/2016_JSLHR-L-15-0325
James W Montgomery, Ronald B Gillam, Julia L Evans
Purpose: Compared with same-age typically developing peers, school-age children with specific language impairment (SLI) exhibit significant deficits in spoken sentence comprehension. They also demonstrate a range of memory limitations. Whether these 2 deficit areas are related is unclear. The present review article aims to (a) review 2 main theoretical accounts of SLI sentence comprehension and various studies supporting each and (b) offer a new, broader, more integrated memory-based framework to guide future SLI research, as we believe the available evidence favors a memory-based perspective of SLI comprehension limitations.
Method: We reviewed the literature on the sentence comprehension abilities of English-speaking children with SLI from 2 theoretical perspectives.
Results: The sentence comprehension limitations of children with SLI appear to be more fully captured by a memory-based perspective than by a syntax-specific deficit perspective.
Conclusions: Although a memory-based view appears to be the better account of SLI sentence comprehension deficits, this view requires refinement and expansion. Current memory-based perspectives of adult sentence comprehension, with proper modification, offer SLI investigators new, more integrated memory frameworks within which to study and better understand the sentence comprehension abilities of children with SLI.
{"title":"Syntactic Versus Memory Accounts of the Sentence Comprehension Deficits of Specific Language Impairment: Looking Back, Looking Ahead.","authors":"James W Montgomery, Ronald B Gillam, Julia L Evans","doi":"10.1044/2016_JSLHR-L-15-0325","DOIUrl":"10.1044/2016_JSLHR-L-15-0325","url":null,"abstract":"<p><strong>Purpose: </strong>Compared with same-age typically developing peers, school-age children with specific language impairment (SLI) exhibit significant deficits in spoken sentence comprehension. They also demonstrate a range of memory limitations. Whether these 2 deficit areas are related is unclear. The present review article aims to (a) review 2 main theoretical accounts of SLI sentence comprehension and various studies supporting each and (b) offer a new, broader, more integrated memory-based framework to guide future SLI research, as we believe the available evidence favors a memory-based perspective of SLI comprehension limitations.</p><p><strong>Method: </strong>We reviewed the literature on the sentence comprehension abilities of English-speaking children with SLI from 2 theoretical perspectives.</p><p><strong>Results: </strong>The sentence comprehension limitations of children with SLI appear to be more fully captured by a memory-based perspective than by a syntax-specific deficit perspective.</p><p><strong>Conclusions: </strong>Although a memory-based view appears to be the better account of SLI sentence comprehension deficits, this view requires refinement and expansion. Current memory-based perspectives of adult sentence comprehension, with proper modification, offer SLI investigators new, more integrated memory frameworks within which to study and better understand the sentence comprehension abilities of children with SLI.</p>","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"77 1","pages":"1491-1504"},"PeriodicalIF":2.2,"publicationDate":"2016-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5399765/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89747652","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Kotilainen, I. Mänttäri, M. Kurhila, P. Hölttä, O. T. Rämö
The Vaasa batholith, western Finland, is a large, peraluminous granitoid pluton that crystallized at 1.88–1.87 Ga during the culmination of the Svecofennian orogeny. The batholith has gradual contacts, through metatexites and diatexites, with the enveloping metasedimentary rocks of the Bothnian Belt. We present ID-TIMS U-Pb age data on monazite from granitoids and xenoliths of the Vaasa batholith and combine these with published U–Pb zircon ages in order to shed further light on the evolution of the Vaasa batholith. The apparent monazite ages for seven of the examined samples are 1870–1863 Ma, and 1855±3 Ma for one further sample from the southern part of the batholith. Combined with pre-existing data, the monazite ages of the granitoids are 9 to 18 Ma (face values) or 3 to 9 Ma (external errors considered) younger than the U–Pb zircon crystallization ages from respective samples. Our new data suggest slow cooling for the Vaasa batholith – the closure/saturation temperature of the monazite U–Pb system was probably reached in ~10 m.y. after the crystallization of magmatic zircon in the examined rocks.
{"title":"New monazite U-Pb age constraints on the evolution of the Paleoproterozoic Vaasa granitoid batholith, western Finland","authors":"A. Kotilainen, I. Mänttäri, M. Kurhila, P. Hölttä, O. T. Rämö","doi":"10.17741/BGSF/88.1.001","DOIUrl":"https://doi.org/10.17741/BGSF/88.1.001","url":null,"abstract":"The Vaasa batholith, western Finland, is a large, peraluminous granitoid pluton that crystallized at 1.88–1.87 Ga during the culmination of the Svecofennian orogeny. The batholith has gradual contacts, through metatexites and diatexites, with the enveloping metasedimentary rocks of the Bothnian Belt. We present ID-TIMS U-Pb age data on monazite from granitoids and xenoliths of the Vaasa batholith and combine these with published U–Pb zircon ages in order to shed further light on the evolution of the Vaasa batholith. The apparent monazite ages for seven of the examined samples are 1870–1863 Ma, and 1855±3 Ma for one further sample from the southern part of the batholith. Combined with pre-existing data, the monazite ages of the granitoids are 9 to 18 Ma (face values) or 3 to 9 Ma (external errors considered) younger than the U–Pb zircon crystallization ages from respective samples. Our new data suggest slow cooling for the Vaasa batholith – the closure/saturation temperature of the monazite U–Pb system was probably reached in ~10 m.y. after the crystallization of magmatic zircon in the examined rocks.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"88 1","pages":"5-20"},"PeriodicalIF":0.7,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67631505","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}
Soapstone industry utilizes different types of soapstone mainly as a construction material for fireplaces. In this application soapstone has to meet different temperature requirements in different parts of fireplaces. Mineralogical and structural information is needed for placing an appropriate type of soapstone in an appropriate position in the fireplace construction. This allows employment of higher temperatures resulting in more particulate-free combustion, which makes it possible for soapstone industry to develop more efficient and environmentally friendly fireplaces. Of many soapstone types, which differ from each other in their chemical composition and thermal properties, carbonate soapstone and its microstructural variations were investigated in this study. A new method was developed to measure thermal shock resistant of natural stones. By exposing carbonate soapstone samples of different textural types to rapid temperature changes, it was possible to determine the parameters that affect the capacity of the rock to resist thermal shock. The results indicate that the type of microtexture is an important factor in controlling the thermal shock resistance of carbonate soapstone. The soapstone samples with a high thermal shock resistance show deformation textures, such as crenulation cleavage and S/C mylonite. A strong negative correlation was observed between the thermal shock resistance and length of cleavage domains in foliated rocks. Also a slight elevation in the iron concentration of talc and magnesite was discovered to improve the thermal shock resistance of carbonate soapstone. Attention should especially be paid to the length and planarity of cleavage domains of spaced foliation.
{"title":"A new method for testing thermal shock resistance properties of soapstone – Effects of microstructures and mineralogical variables","authors":"A. Huhta, A. Kärki, E. Hanski","doi":"10.17741/BGSF/88.1.002","DOIUrl":"https://doi.org/10.17741/BGSF/88.1.002","url":null,"abstract":"Soapstone industry utilizes different types of soapstone mainly as a construction material for fireplaces. In this application soapstone has to meet different temperature requirements in different parts of fireplaces. Mineralogical and structural information is needed for placing an appropriate type of soapstone in an appropriate position in the fireplace construction. This allows employment of higher temperatures resulting in more particulate-free combustion, which makes it possible for soapstone industry to develop more efficient and environmentally friendly fireplaces. Of many soapstone types, which differ from each other in their chemical composition and thermal properties, carbonate soapstone and its microstructural variations were investigated in this study. A new method was developed to measure thermal shock resistant of natural stones. By exposing carbonate soapstone samples of different textural types to rapid temperature changes, it was possible to determine the parameters that affect the capacity of the rock to resist thermal shock. The results indicate that the type of microtexture is an important factor in controlling the thermal shock resistance of carbonate soapstone. The soapstone samples with a high thermal shock resistance show deformation textures, such as crenulation cleavage and S/C mylonite. A strong negative correlation was observed between the thermal shock resistance and length of cleavage domains in foliated rocks. Also a slight elevation in the iron concentration of talc and magnesite was discovered to improve the thermal shock resistance of carbonate soapstone. Attention should especially be paid to the length and planarity of cleavage domains of spaced foliation.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"88 1","pages":"21-46"},"PeriodicalIF":0.7,"publicationDate":"2016-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67631159","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}
Andrei Y. B Arkov, A. A. Nikiforov, R. F. M. Artin
A novel mechanism of spheroidal weathering: a case study from the Monchepluton layered complex, Kola Peninsula, Russia Bulletin of the Geological Society of Finland, Vol. 87, 2015, pp 79–85, http://dx.doi.org/10.17741/bgsf/87.2.003
{"title":"A novel mechanism of spheroidal weathering: a case study from the Monchepluton layered complex, Kola Peninsula, Russia","authors":"Andrei Y. B Arkov, A. A. Nikiforov, R. F. M. Artin","doi":"10.17741/BGSF/87.2.003","DOIUrl":"https://doi.org/10.17741/BGSF/87.2.003","url":null,"abstract":"A novel mechanism of spheroidal weathering: a case study from the Monchepluton layered complex, Kola Peninsula, Russia Bulletin of the Geological Society of Finland, Vol. 87, 2015, pp 79–85, http://dx.doi.org/10.17741/bgsf/87.2.003","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"39 1","pages":"79-85"},"PeriodicalIF":0.7,"publicationDate":"2015-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67631271","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}
Ground-penetrating radar study of the Cena Bog, Latvia: linkage of reflections with peat moisture content
拉脱维亚塞纳沼泽的探地雷达研究:反射与泥炭含水率的联系
{"title":"Ground-penetrating radar study of the Cena Bog, Latvia: linkage of reflections with peat moisture content","authors":"J. Karušs, D. Berzins","doi":"10.17741/bgsf/87.2.004","DOIUrl":"https://doi.org/10.17741/bgsf/87.2.004","url":null,"abstract":"Ground-penetrating radar study of the Cena Bog, Latvia: linkage of reflections with peat moisture content","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"87 1","pages":"87-98"},"PeriodicalIF":0.7,"publicationDate":"2015-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67631393","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}
Peter James Howett, V. Salonen, O. Hyttinen, K. Korkka-niemi, J. Moreau
A hydrostratigraphical approach to support environmentally safe siting of a mining waste facility at Rautuvaara, Finland Based on the construction of a detailed sedimentological model, hydrostratigraphy and local groundwater/surface water flows, this paper analyses the Niesajoki river valley as a suitable area for the expansion of a tailings facility, associated with the nearby Hannukainen (Cu, Au, Fe) mine, Finnish Lapland. Three different glacial/interglacial cycles were identified from the sedimentary observations and, optical stimulated luminescence (OSL) datings showed them to be of Early to Late Weichselian in age. Two groups of hydro-stratigraphical units were identified from hydraulic conductivities. The first, fluvial deposits, lie in the centre of the valley along the valley axis, and are the main aquifers. The second, till group, with lower conductivities, are located on the flanks of the valley. The thickness and complexity of sediments varied across the study area. To the E/SE of the valley, sediments are thick (~40 m), and more complex., In contrast the S/W/NW of the area, sediments are thinner (~10 m) and more simple. Groundwater is found to flow towards the centre of the valley and along its axis, where a bedrock controlled divide forms two groundwater basins. Based on the results of this research, it is suggested that any future expansion of the tailings facility should be restricted to the western and southern side of the valley, where waters are more manageable.
{"title":"A hydrostratigraphical approach to support environmentally safe siting of a mining waste facility at Rautuvaara, Finland","authors":"Peter James Howett, V. Salonen, O. Hyttinen, K. Korkka-niemi, J. Moreau","doi":"10.17741/BGSF/87.2.001","DOIUrl":"https://doi.org/10.17741/BGSF/87.2.001","url":null,"abstract":"A hydrostratigraphical approach to support environmentally safe siting of a mining waste facility at Rautuvaara, Finland Based on the construction of a detailed sedimentological model, hydrostratigraphy and local groundwater/surface water flows, this paper analyses the Niesajoki river valley as a suitable area for the expansion of a tailings facility, associated with the nearby Hannukainen (Cu, Au, Fe) mine, Finnish Lapland. Three different glacial/interglacial cycles were identified from the sedimentary observations and, optical stimulated luminescence (OSL) datings showed them to be of Early to Late Weichselian in age. Two groups of hydro-stratigraphical units were identified from hydraulic conductivities. The first, fluvial deposits, lie in the centre of the valley along the valley axis, and are the main aquifers. The second, till group, with lower conductivities, are located on the flanks of the valley. The thickness and complexity of sediments varied across the study area. To the E/SE of the valley, sediments are thick (~40 m), and more complex., In contrast the S/W/NW of the area, sediments are thinner (~10 m) and more simple. Groundwater is found to flow towards the centre of the valley and along its axis, where a bedrock controlled divide forms two groundwater basins. Based on the results of this research, it is suggested that any future expansion of the tailings facility should be restricted to the western and southern side of the valley, where waters are more manageable.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"87 1","pages":"51-66"},"PeriodicalIF":0.7,"publicationDate":"2015-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67631565","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}
Johanna-Iisebel Järvelill, A. Kleesment, A. Raukas
Accumulation of heavy minerals in the eastern coast of the Gulf of Riga, south-western Estonia Bulletin of the Geological Society of Finland, Vol. 87, 2015, pp 67–78, http://dx.doi.org/10.17741/bgsf/87.2.002
{"title":"Accumulation of heavy minerals in the eastern coast of the Gulf of Riga, south-western Estonia","authors":"Johanna-Iisebel Järvelill, A. Kleesment, A. Raukas","doi":"10.17741/bgsf/87.2.002","DOIUrl":"https://doi.org/10.17741/bgsf/87.2.002","url":null,"abstract":"Accumulation of heavy minerals in the eastern coast of the Gulf of Riga, south-western Estonia Bulletin of the Geological Society of Finland, Vol. 87, 2015, pp 67–78, http://dx.doi.org/10.17741/bgsf/87.2.002","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"87 1","pages":"67-78"},"PeriodicalIF":0.7,"publicationDate":"2015-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67631219","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}
Multi-grain isotope dilution and secondary ion microprobe zircon U-Pb as well as wholerock Rb-Sr isotope dilution data on the late Paleoproterozoic Suomenniemi rapakivi granite complex (exposed on the northern flank of the Wiborg batholith in southeastern Finland) are discussed in the light of point-specific errors on Pb/U and proposed new values of the decay constant of 87Rb, λ87. U-Pb zircon data on hornblende granite and biotite granite of the main metaluminous-marginally peraluminous granite fractionation series of the Suomenniemi batholith indicate crystallization in the 1644-1640 Ma range, with a preferred age at 1644±4 Ma. A cross-cutting hornblende-clinopyroxene-fayalite granite is probably slightly younger, as are quartz-feldspar porphyry dikes (1634±4 Ma) that cut both the main granite series and the metamorphic Svecofennian country rocks of the Suomenniemi batholith. Recalculation of whole-rock Rb-Sr data published on the main granite series of the batholith by Rämö (1999) implies errorchron ages of 1635±10 Ma and 1630±10 Ma and a magmatic Sr/Sri of 0.7062±0.0024. This relatively high initial ratio is indicative of a major Proterozoic crustal source component in the granites of the batholith. The main granite series of the batholith probably cooled relatively rapidly to and below the closure temperature of the Rb-Sr isotope system, with little subsequent subsolidus adjustment. The three discrete silicic magmatic phases of the batholith (the main granite series, the hornblende-clinopyroxene-fayalite granite, and the quartz-feldspar porphyry dikes) were all probably emplaced before the main volume of rapakivi granite (the Wiborg batholith proper) in southeastern Finland. The Suomenniemi batholith thus represents an early magmatic precursor to the classic Wiborg batholith and was emplaced clearly before the massive rise of isotherms associated with the ascent and crystallization of the magmas that formed the bulk of the Wiborg batholith system.
{"title":"Geochronology of the Suomenniemi rapakivi granite complex revisited","authors":"O. T. Rämö, I. Mänttäri","doi":"10.17741/BGSF/87.1.002","DOIUrl":"https://doi.org/10.17741/BGSF/87.1.002","url":null,"abstract":"Multi-grain isotope dilution and secondary ion microprobe zircon U-Pb as well as wholerock Rb-Sr isotope dilution data on the late Paleoproterozoic Suomenniemi rapakivi granite complex (exposed on the northern flank of the Wiborg batholith in southeastern Finland) are discussed in the light of point-specific errors on Pb/U and proposed new values of the decay constant of 87Rb, λ87. U-Pb zircon data on hornblende granite and biotite granite of the main metaluminous-marginally peraluminous granite fractionation series of the Suomenniemi batholith indicate crystallization in the 1644-1640 Ma range, with a preferred age at 1644±4 Ma. A cross-cutting hornblende-clinopyroxene-fayalite granite is probably slightly younger, as are quartz-feldspar porphyry dikes (1634±4 Ma) that cut both the main granite series and the metamorphic Svecofennian country rocks of the Suomenniemi batholith. Recalculation of whole-rock Rb-Sr data published on the main granite series of the batholith by Rämö (1999) implies errorchron ages of 1635±10 Ma and 1630±10 Ma and a magmatic Sr/Sri of 0.7062±0.0024. This relatively high initial ratio is indicative of a major Proterozoic crustal source component in the granites of the batholith. The main granite series of the batholith probably cooled relatively rapidly to and below the closure temperature of the Rb-Sr isotope system, with little subsequent subsolidus adjustment. The three discrete silicic magmatic phases of the batholith (the main granite series, the hornblende-clinopyroxene-fayalite granite, and the quartz-feldspar porphyry dikes) were all probably emplaced before the main volume of rapakivi granite (the Wiborg batholith proper) in southeastern Finland. The Suomenniemi batholith thus represents an early magmatic precursor to the classic Wiborg batholith and was emplaced clearly before the massive rise of isotherms associated with the ascent and crystallization of the magmas that formed the bulk of the Wiborg batholith system.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"87 1","pages":"25-45"},"PeriodicalIF":0.7,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67631481","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}
A. Beucher, S. Fröjdö, P. Österholm, J. Auri, A. Martinkauppi, P. Edén
In Finland, poor water quality and associated ecological damage in the coastal streams related to land use on acid sulfate (a.s.) soils has been drawing a considerable amount of attention since the 1950’s. These soils originate from sulfide-bearing marine sediments mostly occurring in the coastal areas located below the highest shoreline of the former Litorina Sea. Of the many previous studies carried out on soil or water data, quite few gathered both and their geographic extent was relatively limited. This study aimed at assessing a.s. soil probability maps using two chemical indicators measured in the recipient waters (i.e. sulfate content and sulfate/chloride ratio) for 24 catchments along the Finnish coast. All the available data was compiled for these catchments, which were surveyed using different methods (i.e. conventional mapping and two spatial modeling techniques: fuzzy logic and artificial neural networks). High sulfate contents and sulfate/ chloride ratios measured in these rivers were controlled by a.s. soils in the corresponding catchments. The extent of the most probable areas for a.s. soils in the surveyed catchments correlated with the two chemical indicators measured in the recipient waters, suggesting that the probability maps created with different methods are reliable and comparable. The use of a.s. soil related chemical indicators in water, thus, constitutes a complementary, independent and straightforward tool to assess a.s. soil probability maps.
{"title":"Assessment of acid sulfate soil mapping utilizing chemical indicators in recipient waters","authors":"A. Beucher, S. Fröjdö, P. Österholm, J. Auri, A. Martinkauppi, P. Edén","doi":"10.17741/BGSF/87.1.001","DOIUrl":"https://doi.org/10.17741/BGSF/87.1.001","url":null,"abstract":"In Finland, poor water quality and associated ecological damage in the coastal streams related to land use on acid sulfate (a.s.) soils has been drawing a considerable amount of attention since the 1950’s. These soils originate from sulfide-bearing marine sediments mostly occurring in the coastal areas located below the highest shoreline of the former Litorina Sea. Of the many previous studies carried out on soil or water data, quite few gathered both and their geographic extent was relatively limited. This study aimed at assessing a.s. soil probability maps using two chemical indicators measured in the recipient waters (i.e. sulfate content and sulfate/chloride ratio) for 24 catchments along the Finnish coast. All the available data was compiled for these catchments, which were surveyed using different methods (i.e. conventional mapping and two spatial modeling techniques: fuzzy logic and artificial neural networks). High sulfate contents and sulfate/ chloride ratios measured in these rivers were controlled by a.s. soils in the corresponding catchments. The extent of the most probable areas for a.s. soils in the surveyed catchments correlated with the two chemical indicators measured in the recipient waters, suggesting that the probability maps created with different methods are reliable and comparable. The use of a.s. soil related chemical indicators in water, thus, constitutes a complementary, independent and straightforward tool to assess a.s. soil probability maps.","PeriodicalId":55302,"journal":{"name":"Bulletin of the Geological Society of Finland","volume":"87 1","pages":"5-23"},"PeriodicalIF":0.7,"publicationDate":"2015-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67630779","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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