Dissertationen zum Thema „Sulphur and Callcium isotopes“
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Jouini, Arbia. „Perturbations biogéochimiques à la limite Crétacé-Paléogène : apport des isotopes du Soufre et du Calcium“. Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0065.
Der volle Inhalt der QuelleThe Cretaceous-Paleogene boundary (KPg, -66 Ma) is associated to one of the deepest biogeochemical cycle disruptions in Earth's recent history. The events associated to the KPg boundary include one of the strongest known oceanic calcareous bioproduction crisis and are coeval with a bolid impact (that formed the Chixculub crater) and the emplacement of a Large Igneous Province (Deccan traps). Many studies investigated the mechanism(s) triggering the environmental perturbations and many questions remain unanswered regarding the relative contribution of the volcanic event and the impact on the KPg crisis. Yet, modification of the ocean-atmosphere system composition through massive input of sulfuric and carbonic acid very likely played a key, underconstrained, role.During this thesis project, I conducted high-resolution stable sulphur and calcium isotope records across the Cretaceous-Paleogene transition. These records are based on monospecific samples of planktonic and benthic foraminifera from the equatorial Pacific.The benthic and planktonic δ44/40Ca records before and after the K-Pg boundary allowed us to demonstrate a succession of episodes of ocean alkalinity change related to the increase in continental weathering and the biocalcification crisis caused by CO2 emissions from Deccan volcanism. Carbonate compensation through dissolution of carbonate sediments, reduction of biocalcification and/or increase in continental weathering had to occur to compensate for the excess CO2. As a result, this led to rapid changes in oceanic carbonate chemistry, in combination with a reduction in the export of surface alkalinity in response to the early Paleogene planktonic biomineralisation crisisExamination of sulphur cycle disruption instead supports the idea that mass extinction through the K-Pg transition is not associated with a global expansion of anoxic conditions, in contrast to the various Phanerozoic mass extinction events, where there are multiples evidences for the development of anoxic conditions associated with carbon cycle disruption. These findings are consistent with micropalaeontological observations that show no benthic foraminiferal mass extinction.This multi-proxy geochemical approach has the advantage of allowing a more detailed assessment of key parameters such as carbonate chemistry and oceanic anoxia across the Cretaceous-Paleogene transition, thus providing a clearer global picture of biogeochemical perturbations around this time
McArdle, Nicola Clare. „The use of stable sulphur isotopes to distinguish between natural and anthropogenic sulphur in the atmosphere“. Thesis, University of East Anglia, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335422.
Der volle Inhalt der QuellePruett, Lee. „Stable Sulfur Isotope Rations from West Antarctica and the Tien Shan Mountains: Sulfur Cycle Characteristics from Two Environmentally Distinct Areas“. Fogler Library, University of Maine, 2003. http://www.library.umaine.edu/theses/pdf/PruettL2003.pdf.
Der volle Inhalt der QuelleJohn, Eleanor Heulwen. „Strontium and sulphur isotopes and the origin of Mid-Late Palaeozoic mass extinctions“. Thesis, University of Leeds, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493302.
Der volle Inhalt der QuelleJohnson, Malia. „An investigation of stable sulphur isotopes as a palaeodietary indicator in South Africa“. Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11257.
Der volle Inhalt der QuelleHumphries, Stefan. „Stable Isotopes of Sulphur and Oxygen in Forested Catchments: Insight from New Techniques into Sulphur Cycling and Dissolved Organic Matter Alteration“. Thesis, University of Waterloo, 2003. http://hdl.handle.net/10012/1270.
Der volle Inhalt der QuelleDogramaci, Shawan Shawket. „Isotopes of sulphur, oxygen, strontium and carbon in groundwater as tracers of mixing and geochemical processes, Murray Basin, Australia /“. Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phd654.pdf.
Der volle Inhalt der QuelleElshayeb, Monalisa. „Determining food web impacts on experimental aquatic systems from the disposal of oil sands process-affected waste materials“. Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2973.
Der volle Inhalt der QuelleTo determine the potential effects of site construction and OSPM within experimental test sites, carbon and sulphur stable isotopes of water, plankton, aquatic invertebrates and fish were analyzed. With the exception of Chaoborus and Haliplus, all carbon isotope signatures were not significantly different in constructed and reference sites. Also with the exception of Haliplus, sulphur isotope values for aquatic organisms from constructed and reference sites were significantly different. Aquatic organisms and water samples from constructed sites built in, or close, to the boundary of Kcw clays typically had δ34S < 0 ?. Coinciding with depleted δ34S signatures found in these aquatic systems were elevated sulphate concentrations. The waters at experimental test sites are in direct contact with the soil materials that facilitate the accumulation of sulphates as a result of the oxidation of substrate sulphide minerals. In general the results of the study suggest that aquatic food web structure and function do not change with the introduction of OSPM. Shifts in isotopic signatures suggestive of changes in food web structure, however, do occur when site construction exposes Kcw clays in the substrate.
Galeazzo, Tommaso. „Tracking volcanic sulphate : modelling tropospheric volcanic sulphate formation and its oxygen isotopic signatures“. Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS300.
Der volle Inhalt der QuelleVolcanic emissions are a major source of sulphur. Volcanic sulphur is oxidized and forms sulphate aerosols that influence the climate by absorbing and dispersing incident solar radiation. Sulphur emissions in the troposphere influence local and regional climate, but large uncertainties remain regarding oxidation and its conversion into volcanic sulphate aerosols. The oxidation of sulphur in a wide range of volcanic plumes and the influence of volcanic halogens on plume chemistry are studied using a chemical box model. At the same time, the isotopic oxygen composition of volcanic sulphate, namely the excess of 17-O (∆17O), is being explored, which can provide constraints on sulphur oxidation pathways. The results suggest that in the presence of water droplets and ash, the oxidation of sulphur in plumes is mainly due to aqueous phase oxidation with O2 catalyzed by transition metal ions (TMI). Halogen emissions promote the domi- nance of O2 /TMI by inducing ozone depletion events (ODEs). In the absence of water droplets, plume chemistry is largely determined by heterogeneous chemistry on primary sulphate aerosols. The dominant oxidants in these plumes are OH and H2O2. The oxidation rate of sulphur is significantly reduced compared to plumes containing water droplets. The results show that oxygen isotopes in sulphates provide strong constraints on the chemical balance of sulphur in volcanic plumes and on the role of volcanic halogens
Andersson, Karin. „Diet och identitet : Analyser av kol- kväve- och svavelisotoper på indivier från det kristna senvikingatida gravfältet i Björned, Torsåkers socken, Ångermanland“. Thesis, Stockholm University, Department of Archaeology and Classical Studies, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1142.
Der volle Inhalt der QuelleThis paper deals with the late Viking age/early medieval grave field in Björned, Torsåker parish, Ångermanland County in northern Sweden. The grave field in Björned is rare because it has all the signs of being Christianized before the surroundings. This awakes questions such as if the people of Björned came from another place and brought the religion with them or if someone else did that for them. To find these answers I have analysed the stable isotope ratios [delta]13C, [delta]15N and [delta]34S in human bone collagen. Through these stable isotopes we can not only see what the people consumed but also where their food had its origin. It seems like several people from the grave field had a different origin then the rest.
Hagerfors, Erika. „Formation of Sulphides in the Canadian High Arctic Large Igneous Province; Testing the Influence of Sedimentary Rocks“. Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-357415.
Der volle Inhalt der QuelleStora magmatiska provinser (på engelska Large Igneous Provinces, LIPs) är vulkaniska event då enorma mängder magma avsätts över en väldigt stor yta under ett, i ett geologiskt perspektiv, kort tidsspann. Dessa stora vulkaniska utbrott har väckt stort intresse då de är samtida med flera av de största massutdöendena i jordens historia, men också för att en viss typ av sulfidmalm rik på nickel, koppar och platinametaller (Ni-Cu-PGE malmer) ofta förekommer i provinsernas magmagångar och magmakammare. En viktig faktor som till stor del avgör en magmatisk provins påverkan på klimatet och potentiella malmförekomster är inkorporering av sedimentära bergarter till magman som, när de hettas upp, kan frigöra gaser rika på svavel och kol. I Kanadas arktiska öar trängde magma tillhörande den högarktiska magmatiska provinsen (HALIP) in i svart skiffer, karbonater och evaporiter, som är sedimentära bergarter rika på flyktiga ämnen. Denna magmatiska provins erbjuder därför stora möjligheter till att studera interaktionen mellan magma och sedimentära bergarter. Syftet med denna studie är att testa om inkorporering av sedimentärt svavel kan främja bildandet av sulfidsmälta i magma och därigenom bidra till bildandet av sulfidmalmer. Detta görs genom att analysera svavelisotoper i sulfidmineral i prover från en magmagång, som trängde in i en skifferformation, tillhörande den högarktiska magmatiska provinsen i norra Kanada. Genom att analysera svavelisotopkvoten (δ34S) i sulfidmineral kan man få information om huruvida svavlet i mineralen är av sedimentärt ursprung (där skiffer generellt har negativa δ34S värden) eller om svavlet har δ34S värden liknande de från manteln (som har δ34S värden runt 0‰), vilket i så fall skulle innebära att magman inte har inkorporerat sedimentärt svavel. Genom att använda masspektrometri av typen SIMS analyseras totalt 14 sulfidmineralkorn (n = 246 individuella SIMS punkter) för deras svavelisotopkvoter. Resultatet av studien visar att alla analyserade sulfidmineral har mycket negativa δ34S värden mellan -19.5 och -5.7‰ (med ett δ34S medelvärde på -8.2 ± 0.83‰, två standardavvikelser). Genom att jämföra våra δ34S värden med δ34S och δ18O värden för andra prover från både magmagången och den omgivande skiffern kunde vi se att δ34S värdena för sulfidmineralen i de yttre delarna av magmagången har liknande negativa värden som den omgivande skiffern, och att δ34S värdena för skiffern närmast magmagången är mer positiva. Detta tyder på att sedimentärt svavel i kontakten mellan magmagången och skiffern har blivit inkorporerat i magman från den omgivande skiffern. Våra resultat tyder därför på att sulfidmineralen i våra prover från magmagången bildades genom assimilering av svavel från den omgivande skiffern. Detta innebär i sin tur att den kanadensiska högarktiska magma provinsen potentiellt kan vara en källa för sulfidmalm, även om ytterligare studier behövs. Dessutom visar våra resultat att inkorporering av sedimentärt svavel förmodligen ökade de vulkaniska gaserna i magman, vilket kan ha bidragit till klimatförändringar relaterade till den vulkaniska aktiviteten av den högarktiska magmatiska provinsen.
Björkvald, Louise. „Landscape hydrogeochemistry of Fe, Mn, S and trace elements (As, Co, Pb) in a boreal stream network“. Doctoral thesis, Stockholm University, Department of Geology and Geochemistry, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8130.
Der volle Inhalt der QuelleThe transport of elements by streams from headwater regions to the sea is influenced by landscape characteristics. This thesis focuses on the influence of landscape characteristics (e.g. proportion of wetland/forest coverage) on temporal and spatial variations of Fe, Mn, S and trace elements (As, Co, Pb) in streams located in northern Sweden, a boreal region characterized by coniferous forests and peat wetlands.
Water samples from a network of 15 streams revealed a different hydrogeochemistry in forested catchments compared to wetland catchments. The temporal variation was dominated by spring flood, when concentrations of Fe, Mn and trace elements increased in forested headwaters. However, in streams of wetland catchments concentrations decreased, but Pb concentrations were higher in comparison to other streams. Both Fe and Pb showed positive correlations with wetland area, while Co correlated with forest coverage. The anthropogenic contribution of As and Pb appear to be larger than the supply from natural sources.
During spring flood SO42- decreased in most streams, although concentrations increased in streams of wetland catchments. Concentrations of SO42- were higher in streams of forested catchments than in wetland dominated streams, the former being net exporters of S and the latter net accumulators. Isotope values of stream water SO42- (δ34SSO4) were close to that of precipitation during spring flood, indicating that the major source of S is from deposition. The results show that, although emissions of anthropogenic S have been reduced, there is still a strong influence of past and current S deposition on runoff in this region.
In conclusion, wetlands are key areas for the hydrogeochemistry in this boreal landscape. The findings emphasize the importance of understanding stream water chemistry and element cycling from a landscape perspective. This may be important for predicting how boreal regions respond to environmental disturbances such as climate change.
Schyman, Joakim. „Proveniensbestämning av vikingatida hornmaterial : En studie utifrån stabila isotoper“. Thesis, Stockholms universitet, Arkeologiska forskningslaboratoriet, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-78367.
Der volle Inhalt der QuelleHsiao-YuanHsu und 徐筱媛. „The Distribution of Dissolved Sulphur Isotopes of Hot Springs from Eastern Taiwan“. Thesis, 2017. http://ndltd.ncl.edu.tw/handle/th3c2h.
Der volle Inhalt der Quelle國立成功大學
地球科學系
105
This study involves the determination of sulphur (S) isotopes in water samples from hot springs and nearby rivers. The water samples were pre-concentrated, subjected to separation with anion exchange resin AG1-X8 and sulphur isotopic analysis was performed with a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). Concentrations of anions and cations were determined with ion chromatography (IC) and inductively coupled plasma-optical emission spectrometer (ICP-OES), respectively. Samples from western Japan were pre-defined as Na–Cl type ground water, and originated from 'fossil seawater' entrapped in the formations. The K/Cl and SO4/Cl ratios in hot spring water samples were in a range between those of rain water and sea water. The Br/Cl ratios in hot spring water samples were close to that of seawater line, and could be distinguished from river water samples. The δ34S values in most of the hot spring water samples were in the range 15.74-24.87 ‰, and this range is close to δ34S in seawater (+21 ‰). However, δ34S values in water samples from Chibben (Taiwan) and Kurama (Japan) were -1.50‰ and -3.17 ‰, respectively. The lighter sulphur isotope ratios in these two hot water spring resorts indicate the reduction of sulphate, probably by bacteria, because of domestic contamination in the groundwater system. The data on major elements and sulphur isotopes showed that the river water samples, which were collected near hot spring wells, were influenced by the hot springs. Based on the water chemistry of end members i.e., Br/Cl, Na/Cl, K/Cl, SO4/Cl and sulphur isotope signatures, most of the water samples from Eastern Taiwan were considered to be a mixture of rainwater, sulphate fluid from digenetic barite, alternating metamorphic sulphide fluid and sea water (or brine).
Sharman-Harris, Elizabeth. „Geochemical and isotopic studies of the Platreef with special emphasis on sulphide mineralisation“. Thesis, 2008. http://hdl.handle.net/10539/5870.
Der volle Inhalt der QuelleEaton, Sarah Jane. „Source apportionment of sulphate aerosols and gaseous sulphur dioxide over the NW Atlantic during the spring SABINA cruise 2003 using stable sulphur isotopes /“. 2006. http://collections.mun.ca/u?/theses,65956.
Der volle Inhalt der QuelleHafer, M. R. „Origin and controls of deposition of the Wheal Hughes and Poona copper deposits, Moonta, South Australia“. Thesis, 1991. http://hdl.handle.net/2440/86976.
Der volle Inhalt der QuelleThe Wheal Hughes and Poona mines are situated within the Moonta-Wallaroo copper district on the NW region of Yorke Peninsula approximately 150 km NW of Adelaide, S.A. Copper mineralisation is hosted by the Moonta Porphyry, a rhyolite/rhyodacite feldspar porphyry of Early Proterozoic age. The Wheal Hughes and Poona lodes are structurally controlled tabular, en echelon and sheeted fissure veins, which strike 040-050 and have a 45deg to 60deg westerly dip. Two distinct groups of mineralisation are found to occur at Wheal Hughes: (1) the NE Leighton's lode which closely resembles Poona and is typical of Moonta lodes, and (2) the SW Wheal Hughes lode which is unique to the region, in consisting of a series of parallel veins in close proximity and having extensive wall rock alteration. Mineralisation consists predominantly of chalcopyrite and pyrite with minor components of magnetite, hematite, bornite, marcasite, carrollite, molybdenite and gold. A generic model for the mineralisation at Wheal Hughes and Poona is proposed from fluid inclusion studies and petrographic studies, and sulphur isotope, chlorite and sericite analyses together with thermodynamic modelling. Magmatic hydrothermal fluids enriched in metals migrated towards the surface via fractures, which were possibly formed from the emplacement and subsequent cooling of underlying Proterozoic granites. These fractures provided pathways for the migration of hydrothermal fluids as well as sites for the deposition of the ore bodies. Metal deposition occurred as a consequence of a two step boiling process during fluid ascent along fracture conduits, which involved the separation of gases (+ steam) from the liquid phase. Condensation and oxidation of the gas phase produced acid waters that triggered argillic alteration of the country rocks. Two possible heat mechanisms generated the hydrothermal system in the Moonta district; the disruption of the geothermal gradient by the intrusion of an igneous body at depth or a dilatancy/fluid diffusion process. In either case, the heat source generated a hydrothermal system which focussed mineralising fluids into dilatant fractures, effectively localising the mineralisation.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 1991
Dogramaci, Shawan Shawket. „Isotopes of sulphur, oxygen, strontium and carbon in groundwater as tracers of mixing and geochemical processes, Murray Basin, Australia / by Shawan Shwket Dogramaci“. Thesis, 1998. http://hdl.handle.net/2440/19296.
Der volle Inhalt der Quellexxiv, 304 leaves : ill., maps ; 30 cm.
Salinisation of groundwater and surface water of the semi-arid Murray Basin is an issue of vital importance to the viability of agriculture in south-east Australia. The understanding of the transport and transfer of water and salts in large sedimentary aquifers is necessary for better management of water resources in the future. Assesses the usefulness of [detla]34S and [delta]18OSO42 of dissolved SO42- and 87SR/86Sr ratios as tracers of inter-aquifer mixing and rock-water interaction between and within the Murray and Renmark Group aquifers in the south-west Murray Basin.
Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1999?
Spence, Jody. „Weathering and geochemical fluxes in the Canadian Cordillera : evidence from major elements, rare earth elements, mercury, and carbon and sulphur isotopes in the Fraser, Skeena and Nass Rivers“. 2004. http://hdl.handle.net/1828/659.
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