Sökning: "calcite"
Visar resultat 16 - 20 av 70 avhandlingar innehållade ordet calcite.
16. Fluid inclusion studies of the Laisvall sandstone lead-zinc deposit, Sweden
Sammanfattning : The ore forming environment at Laisvall was characterized by a total salt content of 24 eq. wt-% NaCl with as much as 9 wt-% CaCl2. Its temperature fluctuated between 180°C and 120°C but generally decreased with time. The cementing mineral assemblage was deposited in the general sequence calcite, barite, fluorite, galena, sphalerite. LÄS MER
17. Diagenesis and Sequence Stratigraphy : an integrated approach to constrain evolution of reservoir quality in sandstones
Sammanfattning : Diagenesis and sequence stratigraphy have been formally treated as two separate disciplines in sedimentary petrology. This thesis demonstrates that synergy between these two subjects can be used to constrain evolution of reservoir quality in sandstones. LÄS MER
18. Impact of Diagenetic Alterations on Reservoir Quality and Heterogeneity of Paralic and Shallow Marine Sandstones : Links to Depositional Facies and Sequence Stratigraphy
Sammanfattning : This thesis constrains the distribution of diagenetic alterations and their impact on reservoir-quality and heterogeneity evolution pathways in relation to depositional environments and sequence stratigraphy (systems tracts and key sequence stratigraphic surfaces) of four selected paralic and shallow marine siliciclastic successions. Typical eogenetic alterations encountered include the dissolution and kaolinitization of framework silicates, which are closely associated to shoreface facies of forced regressive systems tract (FRWST), lowstand systems tract (LST), upper part of the highstand systems tract (HST), and below the sequence boundary (SB). LÄS MER
19. Diagenesis and Reservoir-Quality Evolution of Paralic, Shallow Marine and Fluvio-lacustrine Deposits : Links to Depositional Facies and Sequence Stratigraphy
Sammanfattning : Linking diagenesis to depositional facies and sequence stratigraphy enables better prediction of spatial and temporal distribution of diagenetic alterations, and thus of evolution of reservoir quality in sandstones. This thesis demonstrates that employing this approach is possible because depositional facies and sequence stratigraphy can provide useful information on parameters controlling the near-surface diagenesis, such as changes in: (i) pore-water chemistry, (ii) residence time of sediments under certain geochemical conditions, (iii) detrital composition and proportion of extra- and intra-basinal grains, and (iv) types and amounts of organic matter. LÄS MER
20. The geology and genesis of lead-zinc veins in Sweden
Sammanfattning : The geology and genesis of Pb-Zn-bearing vein deposits in Sweden have been studied through investigations of their geological setting, vein and alteration mineralogy, wall rock geochemistry, lead and sulfur isotope composition and sphalerite composition, and through thermometric measurements on fluid inclusions from selected veins. The investigated deposits include Subjotnian veins from Älvdalen, Dalslandian veins from Dalsland and Värmskog, Caledonian quartz and calcite veins, Devonian deposits in the Siljan Ring structure, and Variscan veins in SE Scania. LÄS MER