Baigiamajame magistro darbe „Lietuvos geodezinio tinklo horizontaliųjų deformacijų apibendrintųjų charakteristikų tyrimas“ analizuojant geodezinių tinklų elementų pokyčius, nustatytus pagal pakartotinai atliktus geodezinius matavimus, tirtos Lietuvos teritorijos bei jos vakarinio ir rytinio blokų horizontaliosios deformacijos. Baigiamojo magistro darbo tikslas – atlikti Lietuvos geodezinio tinklo horizontaliųjų deformacijų apibendrintųjų charakteristikų tyrimą. Deformacijos, parenkant laisvo taškų poslinkio tolygiai besideformuojančioje dvimatėje erdvėje modelis, apskaičiuotos pagal trianguliacijos bei GPS tinklo kartotinius matavimus. Trianguliacijos matavimai atlikti 1926–1940 metais, GPS matavimai atlikti 1992–1996 metais bei 2007 metais. Horizontaliųjų deformacijų apskaičiuotų Lietuvos teritorijos bei rytinio ir vakarinio blokų tyrimui naudota tenzorinės analizės metodika. Tenzorinės analizės metodu apskaičiuoti Lietuvos teritorijos bei jos vakarinio ir rytinio blokų parametrai. Įvertintos horizontaliųjų deformacijų apibendrintos charakteristikos: didţiausias ir maţiausias santykinis pailgėjimas bei jų kryptys, santykinė dilatacija, antrojo rango deformacijų tenzoriaus elementai bei didţiausio santykinio pailgėjimo kryptys. Darbą sudaro 8 dalys: įvadas, penki skyriai, išvados, literatūros sąrašas. Darbo apimtis – 82 p. teksto be priedų, 36 iliustr., 23 lent., 26 bibliografiniai šaltiniai. Atskirai pridedami darbo priedai. / In the Master thesis called „Investigation of the Generalized Characteristics of the Horizontal Deformations of the Geodetic Network of Lithuania„ analising the changes of the elements of the geodetic networks determinated according to repeatedly performed geodetic measurements were investigated the territories of Lithuania and the horizontal deformations of its west and east blocks. The purpose of the Master thesis is to perform the investigation of the generalized characteristics of the horizontal deformations of the geodetic network of Lithuania. The deformations were calculated according to the repeated measurements of the triangulation and the GPS network by selecting the model of the free displacement of the points in an evenly formed two-dimensional space. The triangulation measurements were performed 1926-1940, the GPS measurements were performed 1992-1996 and in 2007. For the investigation of the horizontal deformations calculated in the territory of Lithuania and in the west and east blocks was used the tensor analysis method. The parameters of the territory of Lithuania and its west and east blocks were calculated using the tensoric analysis method. Also were measured the generalized characterisitcs of the horizontal deformations: the maximum and the minimum relative elongation and their directions, the relative dilatation, the second rank deformations of the elements of the tensor and the directions of the maximum relative elongation. The thesis is composed of 8... [to full text]

The Kiruna mining district, located in the northern Norrbotten ore province, Sweden, is a geologically and economically important area, being the type-locality for Kiruna iron oxide-apatite (IOA) deposits and also host to a variety of other deposits including syngenetic stratiform exhalative Cu-(Fe-Zn) (Viscaria, Eastern Pahtohavare), epigenetic stratabound Cu ± Au (Pahtohavare), and iron oxide-copper-gold (IOCG, Rakkurijärvi) deposits. However, the timing of IOA versus IOCG within the tectonic evolution is in question based on structural investigations showing Cu- and Fe-sulfides occur in late-orogenic structures. Here we use an established tectonic framework to constrain mineral systems (tectonic/thermal drives, metal and ligand sources, fluid pathways, traps, remobilization mechanisms) related to the early and late phases of the Svecokarelian orogeny in the Kiruna mining district. U-Pb zircon geochronology of intrusions in the district indicates a thermal drive was present during the early phase of the Svecokarelian orogeny from ca. 1920-1865 Ma, however remains enigmatic for the late Svecokarelian orogeny. Zircon grains from a magnetite-ilmenite gabbro yielded an age of 1881 ± 8 Ma, coeval with the Kiirunavaara IOA deposit and suggested to represent an important generation of mafic magmatism related to the ore. Lithogeochemistry of early bimodal Svecokarelian intrusions in the district indicates a within-plate to active continental margin environment with a volcanic arc affinity, pointing to a back arc environment. Epsilon Ndi and 87Sr/86Sri values calculated from the U-Pb ages for the igneous intrusions were compared to samples of ore-related alteration from epigenetic Pahtohavare and Rakkurijärvi deposits, district greenstone, and Archean samples. Results show that each deposit sourced Sr and Nd from a variety of rocks suggesting broad fluid transport. Each deposit has a distinct Sr mixing trend suggesting they formed from different ore-forming fluids and pathways. This is supported by new structural data that constrain the folding event and the ore-related quartz-carbonate-sulfide veins in the Pahtohavare area to a late orogenic timing, compared to the early orogenic timing of Rakkurijärvi. Sulfide trace element and sulfur isotope data from structurally constrained ores within the tectonic framework also record distinct characteristics between early and late deposits. However, remobilization of early Pahtohavare sulfides associated to an increase in Co content and heavier sulfur isotope compositions is recorded. The results of this study illustrate that using a structural framework approach to constrain the ingredients of mineral systems is a powerful strategy for interpreting ore deposit processes in tectonically complex terrains where both IOA and IOCG deposits occur.