9 resultados para Devonian formations

em Doria (National Library of Finland DSpace Services) - National Library of Finland, Finland


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This thesis includes detailed sedimentological and ichnological studies on two geological units: the Pebas Formation, with a special focus in its informal upper member, and the Nauta Formation. Both formations were deposited during the Miocene in Northeastern Peruvian Amazonia, in the Amazon retroarc foreland basin. The Pebas and Nauta successions mainly consist of non-consolidated, clastic sedimentary deposits arranged into sand- to mud-dominated heterolithic successions, which can be upward-coarsening to upward-fining. Sediments in both the Pebas and Nauta successions range from mud to fine- to medium-grained sand. The main facies observed were 1) mud-dominated horizontal heterolithic couplets; 2) rooted brownish mud; 3) lenticular, mud-draped, cross-stratified sand; 4) mud- to sand-dominated, inclined heterolithic stratification; 5) sand-dominated horizontal heterolithic couplets; and 6) mud-draped, trough cross-stratified sand. Locally, tidal rhythmites were documented. The facies are interpreted as: 1) muddy, shallow, subaqueous flats/shoals; 2) palaeosols; 3) secondary tidal channels or run-off creeks; 4) tidally influenced point bars; 5) shoreface deposits; and 6) subtidal compound dunes. Thalassinoides-dominated Glossifungites ichnofacies, low-diversity expressions of the Skolithos ichnofacies and depauperate suites consisting of elements common to the Cruziana ichnofacies strongly indicate brackish-water conditions. However, continental trace fossil assemblages, with possible elements common to the Scoyenia ichnofacies, have also been identified. In addition to the palaeoenvironmental study, a local hydrogeochemical characterisation of the Pebas and Nauta formations was also conducted. The geochemistry of the groundwaters reflects the characteristics and the soil geochemistry of the geological formations studied. The Pebas formation has low hardness, acid to neutral waters, whereas the upper Pebas has high hardness, acid to neutral waters. In both units, the arsenic content is locally high. The Nauta formation has low hardness acid groundwaters. A regional review of the Pebas and Nauta formations placed the local observations into a continental perspective and suggests that the whole Pebas-Nauta system was a probably shallow (some tens of metres at maximum), brackish- to freshwater, tidally-influenced epicontinental embayment with a probable semi-diurnal to mixed tidal regime and a microtidal range, surrounded by continental environments such as forest floors, lagoons, rivers and their flood plains, and lakes.

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This PhD study aims to exploit the rich archive provided by the Miocene mollusc fauna of the Pebas Formation and other inland Miocene Amazonian formations to reconstruct landscape evolution and biotic development in lowland Amazonia during the Neogene. Over 160 samples from more than 70 Pebas Formation outcrops mostly collected by the author were processed for this study. Additional samples were collected in Andean areas of Colombia and Venezuela and further material from other northwestern South American basins was studied in museums. Pebas Formation samples and well log data made available by Occidental Peru from three wells in the Marañon Basin in Peru were also investigated. During this study four genera and 74 species from the Pebas Formation have been described and a further 13 species have been introduced in open nomenclature, and several species were reported for the first time. The number of mollusc species attributed to the Pebas fauna has increased from around 50 to 156. The Pebas fauna is characterised as aquatic, endemic and extinct, and is a typical representative of a long-lived lake fauna. Fluvial taxa are not common, (marginal) marine taxa are rare. An additional molluscan fauna from the Miocene Solimões Formation of Brazil, containing 13 fresh water species was also described. The newly documented fauna was used to improve biostratigraphic framework of Miocene Amazonian deposits. Twelve mollusc zones were introduced, the upper eleven of which cover a time interval of approximately seven million years covered previously by only three pollen zones. An age model calculated for the borehole data indicates that the Pebas Formation was deposited between c. 24 and 11 Ma. The areal distribution of the outcropping mollusc zones uncovered a broad dome structure, termed here the Iquitos-Araracuara anteclise in the study area. The structure appears to have influenced river courses and also contributed to edaphic heterogeneity that may have been in part responsible for the current high biodiversity in the study area. The Pebas system was a huge system (> one million km2) dominated by relatively shallow lakes, but also containing swamps and rivers. The system was fed by rivers draining the emergent Andes in the west and lowlands and cratons to the east. The Pebas system was located at sea level and was open to marine settings through a northern portal running through the Llanos Basin and East Venezuela Basin towards the Caribbean. Cyclical baselevel changes possibly related to Mylankhovitch cycles, have been documented in depositional sequences of the Pebas Formation. The composition of the Pebasian mollusc fauna implies that the system was mostly a fresh water system. Such an interpretation is matched by strontium isotope ratios as well as very negative δ18O ratios found in the shells, but is at odds with oligohaline and mesohaline ichnofacies found in the same strata. The mollusc fauna of the Pebas Formation diversified through most of the existence of the lake system. The diversification was mostly the result of in-situ cladogenesis. The success of some of the Pebasian endemic clades is explained by adaptation to fresh water, low oxygen, common unconsolidated lake bottoms (soup grounds) as well as high predation intensity. Maximum diversity was reached at the base of the late Middle to early Late Miocene Grimsdalea pollen zone, some 13 Ma. At the time some 85 species co-occurred, 67 of which are considered as Pebasian endemics. A subsequent drop in species richness coincides with indications of elevated salinities, although a causal relation still needs to be established. Apparently the Pebas fauna went (almost) entirely extinct with the replacement of the lake system into a fluvio-tidal system during the Early Late Miocene, some 11 Ma.

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XML-muotoista tiedonesitystapaa hyödynnetään yhä enemmän esitettäessä rakenteellista tietoa. Tarkoituksena on antaa yleishyödyllinen ja uudelleenkäytettävä tapa jakaa yleistä tietoa erilaisten rajapintojen yli. XML-tekniikoita käytetään myös korjaamaan aiemmin tehdyissä sovellutuksissa esiintyneitä puutteita ja parantamaan niiden toimintaa. Tässä diplomityössä esitellään Telestelle LabView-pohjaiseen testaussovellusympäristöön suunniteltava ajuriuudistus. Työssä paranneltiin aiempaa ajurimallia soveltamalla siihen XML-tekniikoita hyödyntäviä toimintoja. Tarkoituksena oli vähentää testaussovelluskehityksessä vaadittavaa ohjelmointityötä korvaamalla sovelluksiin kovakoodatut ominaisuudet XML-pohjaisilla konfiguraatiotiedostoilla. Järjestelmän pohjana on yleiskäyttöinen ajuri, joka käyttää Telesten omaa EMS-protokollaa kommunikoinnissaan testattavien tuotteiden kanssa. Ajurimalli käyttää XML-pohjaisia konfiguraatiotiedostoja määrittelemään testattavien tuotteiden ominaisuuksia. XML-skeematiedostoilla esitetään ajurin käyttämän kommunikaatioprotokollan viestityypit ja niiden rakenteet. Työn tuloksena onnistuttiin luomaan uudenlainen XML-tekniikoita hyödyntävä ajurimalli. Yhteen yhteiseen ajuriin perustuva malli yhdenmukaistaa testaussovelluksien toteuttamista ja vähentää tarvittavaa ohjelmointityötä. Ajurin käyttöä helpotettiin toteuttamalla testaussovelluksien kehitysympäristöön erityinen editori, jolla voidaan helposti luoda ajuria käyttäviä toimintoja.

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This study is made in the context of basic research within the field ofcaring science. The aim is to make a theoretical and ontological investigation of what the space is in the world of caring. The basic proposition is that the space, as a fundamental dimension, has an impact on how the appreciation of one's mental health and suffering is shaped, and vice versa. The overall purpose is to develop a theoretical model of space from the caring science point of view andalso to offer an ideal concept of space to caring science. Guided by a theoretical horizon (Eriksson 1993, Eriksson 1995, Eriksson 2001) and methodological approach grounded in Gadamer's philosophic and existential hermeneutics a three-stage analysis and interpretation is conducted. The hermeneutic spiral of this investigation starts through a procedure in accordance with Eriksson's model (1997) of concept definition. The goal is to clarify the etymology of the concept as well as semantic differences between synonymous concepts, i.e. to identify the different extents of the concept of `space` (`rum`) in order to bring these closer for an exploration. The second phase is to analyse and interpret a sample of narratives in order to explicate the ontological nature and meaning of the space. The material used here is literary texts. The goal is to clarify the characteristics of the very inside of the space when it is shaped in relation to the human being in encountering suffering. In the third phase an interview study is taken place. The focus of the study is directed towards the phenomenon of space as it is known by a patient in a landscape of psychiatric care, i.e. what the space is in a contextual meaning. Then, a gradual hermeneutic understanding of the space is attempted by using theories from the field of caring science as well as additional theories from other disciplines. Metaphors are used as they are vivid and expressive tools for generating meaning. Different metaphoric space formations depict here a variety of purports that, although not quite the same, share extensive elements. Six metaphorically summarized entities of meaning emerged. The comprehensive form of space is pointed out as the Mobile-Immobile Room. Furthermore, the Standby, the Asylum, the Wall and the Place. In the further dialogue with the texts the understanding has deepened ontologically. The theoretical model ofthe space sums up the vertical, horizontal and the inward extent of deepness inthe movement of mental health. Three entities of ontological meaning have emerged as three significant rooms: the Common Land emerges as the ideal concept of mutual creation in the freedom of doing, being and becoming health. On the interpersonal level it means freedom, which includes sovereignty, choice and dignity of the human being. The Ice World signifies, ultimately, the space as a kind of frozenness of despair which "wallpapers" the person's entire being in the world in the drama of suffering. The Spiritual Home is shaped when the human being has acquired the very core of his/her inner and outer placeness as a kind of "at-homeness" and rootedness. Time is a central element and the inward extent of deepness of this trialectic space. Each of the metaphors is then the human being's unique, although even paradoxical, way of conceiving reality, and mastering spiritual suffering. They condense characteristic structures and patterns of dynamic scenery, which take place within the movement of health. The space encloses a contradictory spatiality constituted through the dynamic field of meaningfulness and meaninglessness. Anyway, it is not through a purging of these contradictions but through bringing them together in a drama of suffering that the space is shaped as ontologically good and meaningful in the world of caring.

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Suurelta osin Natura-alueeseen kuuluvan Kokemäenjoen suistoalueen kuivan maan ja suiston edustan vesialueen erityyppisten maaperäkerrostumien kerrosjärjestys ja alueellinen jakautuminen selvitettiin pintamaaperän kartoituksella, tutkimuskaivannoilla ja kairauksella. Suiston kerrostumat luokiteltiin viiteen maaperämuodostumaan. Vanhimmasta nuorimpaan, Toukari, Vainio-Mattila, Hevosluoto, Lanajuopa ja Säikkä muodostumaan. Nämä edustavat vanhoja Itämeren altaan ja nuorempia merelle päin etenevän suiston eri osien kerrostumisympäristöjä. Eri muodostumien fysikaaliset ja kemialliset ominaisuudet kuvattiin ja ne eroavat luonteeltaan ratkaisevasti toisistaan. Suiston etenemistä edustavat Hevosluoto- ja Säikkä-muodostumat ovat kontaminoituneet 1900-luvun alkupuolelta lähtien yhä voimakkaammin ihmistoiminnasta kertyvistä raskasmetallipitoisuuksista ja orgaanisista haitta-aineista. Tämä näkyy erityisesti elohopean, kadmiumin, arseenin, lyijyn, sinkin, nikkelin, dioksiinien ja furaanien kokonaispitoisuuksien kasvuna näissä muodostumissa. Pitoisuudet ovat suurimpia muodostumien nuorimmissa osissa. Kuivalla maalla raskasmetallipitoisuudet ylittävät paikoin valtioneuvoston pilaantuneelle maaperälle asettamat kynnysarvot, jolloin säädökset on huomioitava suiston maaperää muokattaessa. Vesialueella nämä kynnysarvot ylittyvät myös orgaanisten haitta-aineiden osalta. Tietyin osin ovat esimerkiksi arseenin ja nikkelin osalta taustapitoisuudet suistoalueen vanhimmassa Toukari muodostumassa jo luontaisesti kynnysarvoja suuremmat. Tämä pitää osata ottaa huomioon maansiirtotoimenpiteitä suunniteltaessa. Suistoon kerrostuvan maa-aineksen ja nopean maankohoamisen vuoksi suisto etenee nykyisin 30-40 m vuodessa merialueelle päin. Tämä mataloittaa vääjäämättömästi suiston edustan vesialueita kerrostumisen siirtyessä merelle päin. Näin myös Natura-alueen ainutlaatuiset biotoopit vähitellen siirtyvät merelle päin.

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Different types of laterally extensive sand- and gravel-dominated deposits, up to several tens of metres thick, were investigated in the Suupohja area of western Finland. The studied sediments were deposited in glacial, ice-marginal, glaciofluvial, sea or lake, littoral and terrestrial environments during several glacial-non-glacial cycles. Seventeen pre-Late Weichselian and three Late Weichselian/Holocene sedimentary units were identified. These were divided into ten formally and two informally defined formations that were together termed the Suupohja Group. Every unit are nevertheless not detectable throughout the study area. The informally defined “Karhukangas lower deposits” represent the lowest units in the Suupohja Group. The Karhukangas lower deposits with 5 till units, 3 glaciolacustrine/-marine units and 2 sand units, were interpreted as having been deposited during possibly four glacial-non-glacial cycles before the Late Pleistocene Subepoch (MIS 6 or earlier). The Kankalo Sand above the Karhukangas lower deposits comprises glaciofluvial and aeolian sands of Late Saalian, Eemian or Early Weichselian origin (MIS 6–MIS 5c). The Kariluoma Till above the Kankalo Sand was possibly deposited during the Late Saalian glacial advance, although an Early Weichselian origin is also possible. The Harrinkangas Formation, with glaciofluvial and quiet-water sediments, is interpreted as having been deposited during the Late Saalian and Eemian Stages (MIS 6–MIS 5e). The uppermost units in the deposits studied, the Kodesjärvi Formation (shore deposit), Isojoki Sand (aeolian), Rävåsen Formation (glaciofluvial), Vanhakylä Formation (shore line deposit), Dagsmark Till and Kauhajoki Till, were deposited during the Weichselian Stage (MIS 5d–MIS 2). In addition, Early Holocene (MIS 1) eskers without till cover were informally termed the “Holocene esker deposits”. The Lumikangas Formation represents gravelly shore deposits formed in the Holocene Epoch, when these areas last emerged from the sea. The first Weichselian ice expansion possibly reached the western part of Suupohja in the Early Weichselian Substage (MIS 5d?), but it did not expand further to the east. The second Weichselian glaciation of relatively short duration occupied the southern part of Finland in the later part of Middle Weichselian (MIS 3). Thus, the southern half of the country remained ice-free for the majority (~65–75%) of the Weichselian Stage. Instead, both humid temperate and periglacial conditions alternated. In the initial part of Middle Weichselian, this area was partly submerged, which indicates eastward expansion of the Scandinavian ice sheet(s), depressing the lithosphere. The exceptionally thick sediment cover, multiple lithofacies, relict landscape and preserved preglacially weathered bedrock are evidence of weak glacial erosion in the Suupohja area during the latest as well as earlier glaciations, making this area one of the key areas in Quaternary research.

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The aim of this thesis research was to gain a better understanding of the emplacement of rapakivi granite intrusions, as well as the emplacement of gold-bearing hydrothermal fluids in structurally controlled mineralizations. Based on investigations of the magnetic fabric, the internal structures could be analysed and the intrusion mechanisms for rapakivi granite intrusions and respectively different deformation stages within gold-bearing shear and fault zones identified. Aeromagnetic images revealed circular structures within the rapakivi granite batholiths of Wiborg, Vehmaa and Åland. These circular structures represent intrusions that eventually build up these large batholiths. The rapakivi granite intrusions of Vehmaa, Ruotsinpyhtää within the Wiborg batholith and Saltvik intrusions within the Åland batholith all show bimodal magnetic susceptibilities with paramagnetic and ferromagnetic components. The distribution of the bimodality is related to different magma batches of the studied intrusions. The anisotropy of magnetic susceptibility (AMS) reveals internal structures that cannot be studied macroscopically or by microscope. The Ruotsinpyhtää and Vehmaa intrusions represent similar intrusion geometries, with gently to moderately outward dipping magnetic foliations. In the case of Vehmaa, the magnetic lineations are gently plunging and trend in the directions of the slightly elongated intrusion. The magnetic lineations represent magma flow. The shapes of the AMS ellipsoids are also more planar (oblate) in the central part of the intrusion, whereas they become more linear (prolate) near the margin. These AMS results, together with field observations, indicate that the main intrusion mechanism has involved the subsidence of older blocks with successive intrusion of fractionated magma during repeated cauldron subsidence. The Saltvik area within the Åland batholith consists of a number of smaller elliptical intrusions of different rapakivi types forming a multiple intrusive complex. The magnetic fabric shows a general westward dipping of the pyterlite and eastward dipping of the contiguous even-grained rapakivi granite, which indicates a central inflow of magma batches towards the east and west resulting from a laccolitic emplacement of magma batches, while the main mechanism for space creation was derived from subsidence. The magnetic fabric of structurally controlled gold potential shear and fault zones in Jokisivu, Satulinmäki and Koijärvi was investigated in order to describe the internal structures and define the deformation history and emplacement of hydrothermal fluids. A further aim of the research was to combine AMS studies with palaeomagnetic methods to constrain the timing for the shearing event relative to the precipitation of ferromagnetic minerals and gold. All of the studied formations are dominated by monoclinic pyrrhotite. The AMS directions generally follow the tectonic structures within the formations. However, internal variations in the AMS direction as well as the shapes of the AMS ellipsoids are observed within the shear zones. In Jokisivu and Satulinmäki in particular, the magnetic signatures of the shear zone core differ from the margins. Furthermore, the shape of the magnetic fabric in the shear zone core of Jokisivu is dominated by oblate shapes, whereas the margins exhibit prolate shapes. These variations indicate a later effect of the hydrothermal fluids on the general shear event. The palaeo-magnetic results reveal a deflection from the original Svecofennian age geomagnetic direction. These results, coupled with correlations between the orientation of the NRM vectors and the magnetic and rock fabrics, imply that the gold-rich hydrothermal fluids were emplaced pre/syntectonically during the late stages of the Svecofennian orogeny.

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Meandering rivers have been perceived to evolve rather similarly around the world independently of the location or size of the river. Despite the many consistent processes and characteristics they have also been noted to show complex and unique sets of fluviomorphological processes in which local factors play important role. These complex interactions of flow and morphology affect notably the development of the river. Comprehensive and fundamental field, flume and theoretically based studies of fluviomorphological processes in meandering rivers have been carried out especially during the latter part of the 20th century. However, as these studies have been carried out with traditional field measurements techniques their spatial and temporal resolution is not competitive to the level achievable today. The hypothesis of this study is that, by exploiting e increased spatial and temporal resolution of the data, achieved by combining conventional field measurements with a range of modern technologies, will provide new insights to the spatial patterns of the flow-sediment interaction in meandering streams, which have perceived to show notable variation in space and time. This thesis shows how the modern technologies can be combined to derive very high spatial and temporal resolution data on fluvio-morphological processes over meander bends. The flow structure over the bends is recorded in situ using acoustic Doppler current profiler (ADCP) and the spatial and temporal resolution of the flow data is enhanced using 2D and 3D CFD over various meander bends. The CFD are also exploited to simulate sediment transport. Multi-temporal terrestrial laser scanning (TLS), mobile laser scanning (MLS) and echo sounding data are used to measure the flow-based changes and formations over meander bends and to build the computational models. The spatial patterns of erosion and deposition over meander bends are analysed relative to the measured and modelled flow field and sediment transport. The results are compared with the classic theories of the processes in meander bends. Mainly, the results of this study follow well the existing theories and results of previous studies. However, some new insights regarding to the spatial and temporal patterns of the flow-sediment interaction in a natural sand-bed meander bend are provided. The results of this study show the advantages of the rapid and detailed measurements techniques and the achieved spatial and temporal resolution provided by CFD, unachievable with field measurements. The thesis also discusses the limitations which remain in the measurement and modelling methods and in understanding of fluvial geomorphology of meander bends. Further, the hydro- and morphodynamic models’ sensitivity to user-defined parameters is tested, and the modelling results are assessed against detailed field measurement. The study is implemented in the meandering sub-Arctic Pulmanki River in Finland. The river is unregulated and sand-bed and major morphological changes occur annually on the meander point bars, which are inundated only during the snow-melt-induced spring floods. The outcome of this study applies to sandbed meandering rivers in regions where normally one significant flood event occurs annually, such as Arctic areas with snow-melt induced spring floods, and where the point bars of the meander bends are inundated only during the flood events.

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The need for industries to remain competitive in the welding business, has created necessity to develop innovative processes that can exceed customer’s demand. Significant development in improving weld efficiency, during the past decades, still have their drawbacks, specifically in the weld strength properties. The recent innovative technologies have created smallest possible solid material known as nanomaterial and their introduction in welding production has improved the weld strength properties and to overcome unstable microstructures in the weld. This study utilizes a qualitative research method, to elaborate the methods of introducing nanomaterial to the weldments and the characteristic of the welds produced by different welding processes. The study mainly focuses on changes in the microstructural formation and strength properties on the welded joint and also discusses those factors influencing such improvements, due to the addition of nanomaterials. The effect of nanomaterial addition in welding process modifies the physics of joining region, thereby, resulting in significant improvement in the strength properties, with stable microstructure in the weld. The addition of nanomaterials in the welding processes are, through coating on base metal, addition in filler metal and utilizing nanostructured base metal. However, due to its insignificant size, the addition of nanomaterials directly to the weld, would poses complications. The factors having major influence on the joint integrity are dispersion of nanomaterials, characteristics of the nanomaterials, quantity of nanomaterials and selection of nanomaterials. The addition of nanomaterials does not affect the fundamental properties and characteristics of base metals and the filler metal. However, in some cases, the addition of nanomaterials lead to the deterioration of the joint properties by unstable microstructural formations. Still research are ongoing to achieve high joint integrity, in various materials through different welding processes and also on other factors that influence the joint strength.