Showing papers in "Gff in 1973"
TL;DR: The mean value for dates corrected for the original isotopic fractionation (C13) was 570 years, and that for uncorrected dates was 155 years as mentioned in this paper, rounding off to 550 and 150 years respectively.
Abstract: Samples of shells collected as live specimens in East Greenland around the turn of the century were dated at the Lund Radiocarbon Laboratory, in order to study their apparent ages. The mean value for dates corrected for the original isotopic fractionation (C13) was 570 years, and that for uncorrected dates was 155 years. These were rounded off to 550 and 150 years respectively and are suggested (with a negative prefix) as preliminary sea corrections for the central parts of East Greenland.
66 citations
TL;DR: In this paper, the geometrical geometry of the Seve wedge implies that the major basal thrustplane cuts upwards through the structural and stratigraphic sequences towards the more central zone of the orogenic belt.
Abstract: The westerly, subsurface extension of th; high-grade Seve part of the Seve—Koli Nappe Complex is discussed on the basis of a regional compilation, involving field results from northern Jamtland and southern Vasterbotten, supplemented by a study of existing maps and literature. It is shown that, from Tornetrask in northern Norrbotten to Qvarnbergsvattnet in northern Jamtland, Seve rocks are completely limited to Swedish territory, entering Norway in the Grong area. Suggestions are made regarding their further extension to the south. The geometry of the Seve wedge implies that the major basal thrust-plane beneath the Nappe Complex cuts upwards through the structural and stratigraphic sequences towards the more central zone of the orogenic belt.
52 citations
TL;DR: In this article, both modes of formation are discussed on the basis of some geochemical features of the ores and their host rocks and the features mostly favour a magmatic origin.
Abstract: The idea of a volcanic-sedimentary origin for the iron ores in the Kiruna area, northern Sweden, has recently been presented by Parak (1973a). The previous and most commonly accepted hypothesis for the formation of the iron ores of the Kiruna type is that they are magmatic. In the present paper, both modes of formation are discussed on the basis of some geochemical features of the ores and their host rocks. The features mostly favour a magmatic origin. In the Precambrian, the contemporaneous formation of iron and phosphorus in sediments is a rare phenomenon, whereas it is not uncommon among magmatic rocks.
48 citations
TL;DR: In this paper, the most important factor influencing the composition of the sediments is weathering, while grain size has a relatively small effect, and the influence of source rock is only noticeable as regards the most unweathered materials.
Abstract: Chemical analyses of clays, shales and slates from different parts of the world and from different sedimentological environments have been collected, together with analyses of the most common minerals found in these sediments. It is shown how these chemical compositions are distributed within a triangular diagram with the following molecular numbers in the corners: FeO (total iron)+MgO, Al2O3 and K2O + Na2O + CaO (does not include calcium present as carbonate). The most important factor influencing the composition of the sediments is weathering, while grain size has a relatively small effect. The influence of source rock is only noticeable as regards the most unweathered materials. On the basis of this triangular diagram a new classification system is introduced.
43 citations
TL;DR: Shatter cones have been found at five localities on the dome of the Siljan structure, northwest of Stockholm as discussed by the authors, which provides further support for the interpretation that this structure was formed by a meteorite impact.
Abstract: Shatter cones have been found at five localities on the dome of the Siljan structure, northwest of Stockholm. This provides further support for the interpretation that this structure was formed by a meteorite impact.
41 citations
TL;DR: In this article, the authors discuss the problem of "ball textures" in sulphide ores and suggest an alternative explanation to that proposed by Geijer (1971) for the Swedish Precambrian kulmalmer.
Abstract: The author discusses the problem of “ball textures” in sulphide ores and suggests an alternative explanation to that proposed by Geijer (1971) for the Swedish Precambrian kulmalmer. Similar ore types in the Norwegian Caledonides seem to be the products of the extreme deformation of sulphide ores formed during the pre-orogenic, volcanic-sedimentary stage of the development of the Caledonian geo-synclinal belt.
21 citations
TL;DR: In this article, the conodont species Pygodus serrus (Hadding) and Eoplacognathus reclinatus (Fahraeus) are associated with the Didymograptus murchisoni graptolite Zone.
Abstract: Shaly strata of the Didymograptus murchisoni Zone at Killerod, Skane, southern Sweden, have yielded elements of the conodont species Pygodus serrus (Hadding) and Eoplacognathus reclinatus (Fahraeus) which are characteristic of the Folkeslunda Limestone of late Lasnamagian age. These species provide the first conclusive evidence that at least part of the late Lasnamagian is coeval with the Didymograptus murchisoni graptolite Zone. The presence of Pygodus anserinus Lamont and Lindstrom and Prioniodus prevariabilis Fahraeus throughout the “Bronni Beds” at Killerod proves that this unit is older than has been believed previously and is equivalent to part of the Glyptograptus teretiusculus Zone rather than to the Nemagraptus gracilis Zone. Other evidence for the correlation between the North Atlantic graptolite and conodont zonal successions is also reviewed.
20 citations
TL;DR: The most remarkable feature of the genus Hyperchilarina, the adventral row of spines on the smaller left valve, is considered as a homologon of the velum of the Palaeocopa as discussed by the authors.
Abstract: The genus Hyperchilarina — hitherto known only from North America — is fairly common in the Ordovician of Europe. A detailed description is given from published and new material. The most remarkable feature of the genus — the adventral row of spines on the smaller left valve — is considered as a homologon of the velum of the Palaeocopa. The hypothesis is stated that the main adventral structures of the Palaeocopa — the velum and the marginal structure — were originally structures of the contact margin, and an evolution model is given. Hyperchilarina is possibly identical with Aparchites. It seems that at least both belong to one family. The Aparchitacea are considered as a new sub-order (Leiocopa) on their own, beside the Palaeocopa, because of the missing antral and cruminal dimorphism and the original features of Hyperchilarina. In the course of the description, three new species are established.
19 citations
TL;DR: The Loftahammar granitic gneisses in the Vastervik area of south-eastern Sweden yield an eight-point Rb-Sr whole-rock isochron age of 1598 ± 35 m.y. as discussed by the authors.
Abstract: The Loftahammar granitic gneisses in the Vastervik area of south-eastern Sweden yield an eight-point Rb-Sr whole-rock isochron age of 1598 ±35 m.y. (87Rb half-life = 47.2×109 years) or 1694±35 m.y. (87Rb half-life = 50.0×109 years), with initial 87Sr/80Sr ratio = 0.7131 ±0.0041 (errors with 95 per cent confidence level). A sample from a dike of late-syntectonic younger granite cutting the gneisses also fits this isochron. The rather high initial Sr ratio indicates a pre-metamorphic Rb-Sr record, possibly of the order of some 125 million years. It is inferred that all Svecofennian events of deformation, metamorphism and magmatism distinguished in this area may have taken place within this time-span.
17 citations
TL;DR: In this article, the authors attempted to ascertain the possibility of establishing former salinity conditions from analyses of the extractable cation content of sediments and the influence of factors other than palaeosalinity, such as the cation-exchange capacity of the sediment and post-depositional changes, is stressed.
Abstract: The present investigation attempts to ascertain the possibility of establishing former salinity conditions from analyses of the extractable cation content of sediments. The influence of factors other than palaeosalinity, such as the cation-exchange capacity of the sediment and post-depositional changes, is stressed. Three sites, each with different characteristics, have been studied. The first site, Kyrkviken, comprises sediment deposited during the Ancylus and Littorina periods. The sediment sequence is relatively homogeneous with respect to its physical characteristics. The second site, Rassan, consists of an isolation sequence with a transition from clay-gyttja to a gyttja with a very low minerogenic content. The physical properties of the sediment consequently varies considerably through the profile. The third site, Angskar, is a sea inlet which has yet to be isolated, where the sediment also changes from clay-gyttja to gyttja. Wet density, dry matter, carbon content, exchangeable Mg, Ca, Na ...
15 citations
TL;DR: The basalt of Gobnehall in southern Sweden was dated by the K/Ar method as mentioned in this paper, and the calculated ages of the minerals and whole rocks vary between 128 and 165 m y.
Abstract: The basalt of Gobnehall in southern Sweden was dated by the K/Ar method The calculated ages of the minerals and whole rocks vary between 128 and 165 m y A preliminary calculation of the corresponding isochron yielded an age of 163 m y, that is, a Jurassic age
TL;DR: In this article, the authors examined the origin of the saxonic structures from the viewpoint of the interplay of two factors: (1) a regional and long-lasting en bloc uplift of the Baltic Shield, accompanied by the successive displacement of fault-blocks.
Abstract: This paper is the result of observations made of the Later Triassic-Jurassic tectonic movements in Skane. The gentle structural movements during Upper Triassic deposition occurred against the background of the orogenic events of the Variscian Era. These relations may be visualized from the accompanying section (Fig. 1). The origin of the saxonic structures is examined from the viewpoint of the interplay of two factors: (1) a regional and long-lasting en bloc uplift of the Baltic Shield, accompanied by (2) the successive displacement of fault-blocks — differential movements, in which periods of denudation or sedimentation alternated. The Upper Triassic in Skane was a period of crustal quiescence; the tectonic movements were of an epeirogenic nature. These movements were the forerunners of orogenic disturbances in the Upper Jurassic, but already in the basal Liassic, at the base of the Fleninge sandstone, angular unconformities and other indications of orogenic disturbances occur (Figs. 2 and 3). T...
TL;DR: Radiocarbon dates and tephra layers allow a fairly accurate dating of a sequence of vegetation changes and possible climatic changes as mentioned in this paper, and evidence is given for a glacial advance at about 2,500 B. P.
Abstract: Radiocarbon dates and tephra layers allow a fairly accurate dating of a sequence of vegetation changes and possible climatic changes. This sequence begins with open woodland and a relatively moist climate at the beginning of the Boreal period (c. 9,000 B. P.), passes through a long forested interval with two periods when the bog surface was sufficiently dry to be colonised by trees, and ends with a decline of the forest probably coincident with the arrival of the Norse settlers in 1,080 B. P. Evidence is given for a glacial advance at about 2,500 B. P.
TL;DR: In this article, a lump of clay was found embedded in glaciofluvial, intermorainic, silty sand and a sample of the clay as well as samples of the over and underlying till were investigated for pollen and diatoms.
Abstract: A lump of clay was found embedded in glaciofluvial, intermorainic, silty sand. A sample of the clay as well as samples of the over- and underlying till were investigated for pollen and diatoms. Tha diatoms found in the clay suggest a marine, sublittoral to littoral environment. The pollen content of the clay was small. Corroded pollen of Tilia platyphylla-type predominated. The clay is probably a part of an old sediment of interglacial age, originating perhaps from the Eem period and re-bedded during the last glaciation.
TL;DR: It is shown that the Zeliszkellinae, to which members of this group have been assigned, contains forms with two basically different thoracic types and it is suggested that these should be given greater weight than in existing classifications.
Abstract: A distinctive new species, referable to Dalmanitina (Dalmanitina), is described from probable Ashgillian rocks in Victoria (Australia). This is the first described species of the subgenus from the southern hemisphere. It is shown that the Zeliszkellinae, to which members of this group have been assigned, contains forms with two basically different thoracic types and it is suggested that these should be given greater weight than in existing classifications.
TL;DR: Radiocarbon measurements of organic material in early Flandrian clays at Somero, southwestern Finland, supported the earlier conclusion, based on a study of the pollen and diatom content of these clays, that most of the microfossils and the organic material were re-deposited from interglacial Eemian sediments as mentioned in this paper.
Abstract: Radiocarbon measurements of the organic material in the early Flandrian clays at Somero, southwestern Finland, supported the earlier conclusion, based on a study of the pollen and diatom content of these clays, that most of the microfossils and the organic material were re-deposited from interglacial Eemian sediments.
TL;DR: Till wedges are reported from the Milford Gypsum quarry in Nova Scotia, Canada as discussed by the authors, where they are believed to have been formed by the cracking-and-filling mechanism.
Abstract: Till wedges are reported from the Milford Gypsum quarry in Nova Scotia, Canada. The till wedges are believed to have been formed by the cracking-and-filling mechanism. Till wedges have previously only been reported from Ontario, Connecticut and southern Sweden.
TL;DR: The Swedish contribution to the Geodynamics project includes two major undertakings as mentioned in this paper, which include a geotraverse in the Caledonides (Ostersund-Storlien area), with the aim of studying past crustal movements during a Caledonian cycle and studies of postglacial earth movements in the Baltic Shield.
Abstract: A national committee for the Swedish participation in the Geodynamics Project has been established. The Swedish contribution to the programme includes two major undertakings. A. A geotraverse in the Caledonides (Ostersund-Storlien area), with the aim of studying past crustal movements during the Caledonian cycle. B. Studies of Post-glacial earth movements in the Baltic Shield. These studies include investigations of the istostatic uplift and other present movements in the earth's crust, for example, earth tides and seismic activity. Both undertakings emphasise an inter-disciplinary approach, with contributions from scientists in the field of geology, geophysics and geodesy.
TL;DR: The significance of "till wedges" is questioned in this paper, where it is suggested that they are not unique features and that the evidence presented could equally well be interpreted as density re-adjustments in sediments deposited supraglacially.
Abstract: The significance of “till wedges”, as recently described by N.-A. Morner, is questioned. It is suggested that they are not unique features and that the evidence presented could equally well be interpreted as density re-adjustments in sediments deposited supraglacially. Thus it is doubtful whether they can be used as palaeoglacier flow vectors.
TL;DR: In this article, two cores of Wenlockian rocks in the Ostra Odarslov area of Skane are described, which consist of grey shale intercalated with yellowish-grey laminae and thin beds of dark, dense, silicified limestone.
Abstract: Two cores drilled through late Wenlockian rocks in the Ostra Odarslov area of Skane are described They consist of grey shale intercalated with yellowishgrey laminae and thin beds of dark, dense, silicified limestone There are also thin beds of dense, non-stratified, silicified shale The shale contains a meagre fauna, consisting mainly of poorly preserved graptolites Core No 1 is characterized by Pristiograptus dubius (Suess) and Gothograptus nassa (Holm) No other determinable graptolites have been found The fauna is considered to be an equivalent to the nassa/dubius Interregnum of Jaeger (1959), belonging to the uppermost Wenlock In core No 2, P dubius predominates Monograptus cf flemingii (Salter) and M testis cf inornatus Elles occur sparsely Cyrtograptus lundgreni Tullberg is relatively common, and a fragmentary specimen of C radians Tornquist has been found Some species of inarticulate brachiopods, Cardiola interrupta (Sowerby), two specimens of hyolithids and some flattened
TL;DR: In Dalsland, Central Sweden, granites have been met with in three different areas along the western margin of the Dal Synclinorium, intruding into sediments as mentioned in this paper.
Abstract: In Dalsland, Central Sweden, granites have been met with in three different areas along the western margin of the Dal Synclinorium, intruding into sediments of the Dal Group. The intrusions form small plutons, which are possibly related to major fractures in the crystalline basement.
TL;DR: In this article, a plane-stress analysis of the boudinage structure suggests explanations of the barrel shape of boudins and the deposition of mobile chemical elements between them.
Abstract: The finite-element method of analysis is described, and its use in solving finite-deformation and stress problems is demonstrated. A plane-stress analysis of boudinage structure suggests explanations of the barrel shape of boudins and the deposition of mobile chemical elements between boudins. A study of the change in the fold geometry of laterally compressed layers shows that simultaneous, finite buckling and layer-shortening is a plausible explanation of the formation of similar folds. An application of the method to the growth of diapirs of finite size in a two-layer system illustrates theoretically the shapes and normal stress distributions in diapirs at different stages of growth.
TL;DR: In this article, age determinations of a Quaternary carbonate concretion have been made and it is concluded that a mathematical model given by Berner (1968) for the growth of concretions is reasonable.
Abstract: Age determinations of a Quaternary carbonate concretion have been made. The innermost part is the oldest (8230±120 or 8470±20 years) and the outermost part is the youngest (6730±130 or 6920±130 years). Although the figures are quite uncertain, it may be concluded that a mathematical model given by Berner (1968) for the growth of concretions is reasonable.
TL;DR: The first report on till wedges in Europe as discussed by the authors was published in 1973, with the title "Till wedges: a reply." The paper was published by Geologiska Foreningen i Stockholm Forhandlingar.
Abstract: (1973). The first report on “till wedges” in Europe — a reply. Geologiska Foreningen i Stockholm Forhandlingar: Vol. 95, No. 1, pp. 156-157.
TL;DR: In this paper, Posidonia aranea Tozer (Bivalvia), of the latest Lower Triassic (Spathian) age, and representatives of the Middle Triassic ammonoid genera (Stenopopanoceras, Hollandites, Anagymnotocers, Japonites, Intornites, Isculites, Leiophyllites and Ussurites) are recorded from the Torellneset area, Nordaustlandet, Spitsbergen, from a collection made by O. Kulling
Abstract: Posidonia aranea Tozer (Bivalvia), of the latest Lower Triassic (Spathian) age, and representatives of the Middle Triassic (Anisian) ammonoid genera (Stenopopanoceras, Hollandites, Anagymnotoceras, Japonites, Intornites, Isculites, Leiophyllites and Ussurites) are recorded from the Torellneset area, Nordaustlandet, Spitsbergen, from a collection made by O. Kulling in 1931. Hollandites and Anagymnotoceras indicate that beds of Middle Anisian age are represented.
TL;DR: Microdinium displays a tabulation formula which was previously unknown among fossils and which resembles and suggests the affinities of Microdinium with representatives of the modern family Cladopyxidae (Kofoid 1907) Balech, 1964.
Abstract: Microdinium Cookson & Eisenack, 1960 (type genus), and Eisenackia Deflandre & Cookson, 1955, have both been included in the cyst family Microdiniaceae. However, new information on the tabulation shows them to represent fundamentally different lineages. Microdinium displays a tabulation formula which was previously unknown among fossils and which resembles and suggests the affinities of Microdinium with representatives of the modern family Cladopyxidae (Kofoid 1907) Balech, 1964. Eisenackia displays a Gonyaulax-type tabulation and is transferred from the Microdiniaceae to the Gonyaulacaceae.
TL;DR: The eriticism by Worsley of my paper on till wedges is based on mistakes and misunderstandings as discussed by the authors, and a close examination of the argumentation reveals its weaknesses.
Abstract: The eriticism by Worsley of my paper on till wedges is based on mistakes and misunderstandings. A close examination of the argumentation reveals its weaknesses. After having been properly named and discussed by Dreimanis and by Morner, “till wedge” (in Swedish morankil) is now a specific geological term covering both morphology and genesis. Till wedges are formed by cracking-and-filling or squeczing-in.
TL;DR: The post-Jotnian Ulvo Dolerite intruded into the coastal area of Angermanland, Sweden as discussed by the authors, at least 200 m thick and dips gently south-east, penetrating sub-jotnian intrusive rocks and Jotnian sediments in the south, and Svecokarelian gneisses and granites in the north.
Abstract: The post-Jotnian Ulvo Dolerite intrudes into the coastal area of Angermanland, Sweden It is at least 200 m thick and dips gently south-east, penetrating sub-Jotnian intrusive rocks and Jotnian sediments in the south, and Svecokarelian gneisses and granites in the north. The dolerite has alkali basalt affinities and is layered, the latter being interpreted as the result of gravitational settling. Primary structures are frequent, and several varieties of igneous layering have been identified. Dolerite pegmatite and monzonitic dolerite are also common. The intrusion has been sampled for whole-rock and mineral analysis.
TL;DR: In this article, data on the mercury content of sediment samples from two lakes situated in an area not influenced by industrial pollution was given. But the results were limited to two lakes, and only pike were found with a high mercury content.
Abstract: Data are given on the mercury content of sediment samples from two lakes situated in an area not influenced by industrial pollution. In one of the lakes, pike were found with a high mercury content. To date the sediments, the increase of the frequency of the Picea pollen is used. The mercury content of the sediments is quite constant and has in part been fairly high for at least the last 3 000 years.
TL;DR: In this paper, the casts are interpreted as primary infillings of fissures created by repeated cracking of the ground by frost, i.e., a type of fossil sand-wedges.
Abstract: Some observations of fissure-like casts in deposits of eolian sand are discussed. The very distinct stratification on both sides of the fissures has not been affected by wedging activity or only slightly in some cases. The casts are interpreted as fossil, primary infillings of fissures created by repeated cracking of the ground by frost, i.e. a type of fossil sand-wedges.