No description available.

The fundamental forces of adhesion are responsible for the spreading of fluids such as crude oil/brine on the reservoir rock surface. These physico-chemical interactions determine the surface energetics of a reservoir and thus their wetting phenomena. Inverse Gas Chromatography is introduced to characterize the surface energy of carbonates (calcite and dolomite) and sandstones (Ottawa sand and Berea sandstone). The behavior of the polar and non-polar interaction forces was investigated at varying water coverage and at different temperatures. The results indicated that in general as the water coverage increased, the Lifshitz-van der Waals component of surface energy decreased to nearly that of the bulk water, while the acid-base component also showed a decreasing trend. The Lifshitz-van der Waals component of surface energy always decreased with increase in temperature, while the acid-base properties mostly increased with temperature with the exception of calcite. / text

The Dolomite Alps of northern Italy are a classic field locality in the development carbonate stratigraphic theory. Included in the many discoveries rooted in the geology of the Dolomites is the concept of a hierarchy of stratigraphic forcing in the Alpine Triassic. The hierarchy states that carbonate sedimentation is dominantly a record of eustasy, resulting in organized stacking patterns, and that these stacking patterns reflect the interplay between low frequency (1-10 my) eustatic cycles and their component bundled high-frequency (100 & 20 kyr) eustatic cycles. The overall aim of this study is to further investigate the validity of the hierarchical model after recent dating of Anisian and Ladinian successions called the Milankovitchian periodicity and/or allocyclicity of the cyclic series into question. The study was completed using four sub-studies, 3 based on data collected in the field and a fourth based in cycle theory and computer modeling. First, it can be shown that allocyclic forcing exists in the Anisian/Ladinian platforms of the Dolomites by comparing the stratigraphic sections measured from 2 time-equivalent, independent carbonate platforms, the Latemar and Mendola Pass. Second, computer modeling of Anisian/Ladinian carbonate platform stratigraphy using Milankovitchain solar insolation as a proxy for high-frequency eustasy shows that both pure Milankovitch forcing and mixed Milankovitch/sub-Milankovitch forcing will produce synthetic carbonate platforms with stratigraphic successions comparable to those of the Anisian/Ladinian platforms of the Dolomites. Third, it can be shown that the while the Norian Dolomia Principale (a regional carbonate shelf) was affected by differential subsidence, megacycles systematically increase in their number of component cycles from 2-3:1 in the eastern Dolomites (updip) to 5-6:1 in the western Dolomites (seaward). In conclusion, the concept that carbonate platform stratigraphy is a record of an interplay between eustasy, subsidence, and sedimentation is upheld, while the validity of Milankovitchian forcing acting on all Alpine carbonate cycles is questioned. Instead, cyclic carbonates with sub-Milankovitch periodicities were common in the early and mid-Triassic, while cycles with Milankovitchian periodicities were common in the late Triassic. / text

No description available.

Στην διάρκεια της παρούσας εργασίας μελετήθηκε η ικανότητα ρόφησης CΟ2 καθώς και η απομείωση (attrition) δώδεκα υλικών (8 ασβεστίτες και 4 δολομίτες) τόσο πριν όσο και αφού είχαν υποστεί θερμική διάσπαση-ενανθράκωση. Σύμφωνα με τα αποτελέσματα τα μη θερμικά κατεργασμένα υλικά επέδειξαν μικρότερα ποσοστά απομείωσης συγκριτικά με τα θερμικά κατεργασμένα. Το ποσοστό απομείωσης των υλικών χωρίς θερμική κατεργασία δεν αποτελεί μέτρο πρόβλεψης του ποσοστού απομείωσης του υλικού μετά από θερμική κατεργασία. Στην συνέχεια μελετήθηκε η επίδραση των συνθηκών θερμικής διάσπασης (θερμοκρασία και διάρκεια) του υλικού Α1 με αρχικό μέγεθος κόκκων 0.71mm<d<1.4mm τόσο στην ικανότητα ρόφησης διοξειδίου του άνθρακα όσο και στον ποσοστό απομείωσης (attrition). Τα αποτελέσματα έδειξαν ότι όταν τα υλικά διασπόνται έντονα θερμικά (Τ>900οC και t>2h) παρουσιάζουν μειωμένη ικανότητα ρόφησης CΟ2 . Αναφορικά με την απομείωση, θερμική κατεργασία σε υψηλή θερμοκρασία και για παρατεταμένη χρονική περίοδο, οδηγεί σε υψηλά ποσοστά λεπτόκοκκου υλικού μετά την ενανθράκωση. Πιθανοί λόγοι είναι η θραύση των κόκκων λόγω της ανισότροπης δομής των υλικών η ή πυροσυσσωμάτωση (sintering). Τέλος μελετήθηκε η επίδραση υλικών επικάλυψης όπως η αλούμινα και η σίλικα στην ικανότητα ρόφησης CΟ2 καθώς και στο ποσοστό απομείωσης του υλικού Α1 για αρχικό μέγεθος κόκκων 0.5mm<d<0.6mm και 0.71mm<d<1.4mm. Τα αποτελέσματα έδειξαν ότι και στις δύο μελετηθείσες κοκκομετρίες η διεργασία της επικάλυψης δεν έδωσε θετικά αποτελέσματα στο ποσοστό απομείωσης του υλικού. Μικρότερο ποσοστό απομείωσης παρουσίασε το υλικό Α1 όταν επικαλύφθηκε με 0,5% Al2O3 . Κανένα θετικό αποτέλεσμα σχετικά με το ποσοστό απομείωσης του υλικού Α1 και στις δύο κοκκομετρίες δεν επιτεύχθηκε ούτε όταν την διεργασία της επικάλυψης ακολουθούσε και διεργασία έντονης θερμικής κατεργασίας. Η ικανότητα ρόφησης διοξειδίου του άνθρακα του υλικού δεν επηρεάζεται από την διεργασία της επικάλυψης ούτε και από τον συνδυασμό επικάλυψης έντονης θερμικής κατεργασίας. / Testing of the attrition resistance and CO2 absorption capacity were done for twelve raw and calcined/recarbonated materials. Attrition performance was tested with a simple method employing a small scale fluidized bed at room temperature. Eight materials were characterized as calcites and four as dolomites with XRD technique. Calcined-recarbonated materials showed higher attrition than raw ones. Excellent attrition performance of a raw material does not mean same performance after calcination and recarbonation. Investigation of the effect of calcination condition (temperature, time) on the absorptive and mechanical properties of materials A1, A7, A8, Δ1, Δ2, Δ3 and Δ4 was carried out. It was found that the conditions of calcination do not have an important effect on attrition behavior. On the other hand the severity of calcination has a clear negative effect on CO2 absorption capacity for all materials tested. This is a direct consequence of the sintering and densification that takes place at high temperatures and long calcination times. In order to improve attrition performance some coating experiments were performed with A1 material for initial particle size fraction of 0.5mm<d<0.6mm and 0.71mm<d<1.4mm. Commercially available silica (two types) and alumina (one type) in the form of aqueous colloidal solutions with neutral/basic pH in the case of silica and acidic in the case of alumina were used in coating experiments. Coating with silica (two types) did not prove to have either positive or negative effect on both CO2 absorption capacity and attrition performance for A1 material with initial particle size fraction of either 0.5mm<d<0.6mm or 0.71mm<d<1.4mm. A small positive effect on attrition performance for A1 material was noticed when it was coated with 0.5% alumina. Combination of coating with intense calcination conditions (950οC for 6h) did not have any positive effect on attrition performance for A1 material with initial particle size fraction of either 0.5mm<d<0.6mm or 0.71mm<d<1.4mm.

This thesis attempts to interpret the metamorphic condition and fluid composition experienced by metacarbonates on Utö, located in the south-eastern parts of the Stockholm archipelago. Utö is a part of the Svecofennian domain, and the area Bergslagen, that has hosted several mines over the last millennia. The bedrock in this area has been dated by the U-Pb technique to 1.90-1.87 Ga, placing it in the Paleoproterozoic era (Allen et al. 1996, Lundström et al. 1998). The rocks, of the studied area on the island of Utö, are mainly metacarbonates with a varying purity and thin layers of volcanic ash. These rocks become more felsic towards the north-western coast as the layers of felsic ash become more dominant. To determine the P-T-XCO2 of metamorphism, metacarbonates were examined, in the field, in thin sections and mineral chemistry was determined by SEM analysis. Three samples were collected along a 1km transect, along which the assemblage calcite + dolomite + quartz + tremolite + diopside was observed. Petrographic and SEM analysis were performed to gather chemical data from coexisting calcite and dolomite in order to calculate temperature using the calcite-dolomite geothermometer. Chemical data from the SEM analysis were also run with AX and THERMOCALC together with pressure data received from a study by Engström (2011) of the adjacent island, Persholmen, to generate a T- XCO2 diagram. Pressure was estimated to 3.1 +/- 1.3 kbars, temperature calculated to 442°C 30°C and XCO2 to range from 0,00067-0,0038 with the standard deviation taken in to account. These results record equilibration with a CO2-bearing hydrous fluid at greenschist facies conditions. / Metamorphic map of Sweden

No description available.

Detailed studies, both chemical and physical, have been performed on various dolomites and vug-filling carbonates, to determine the pathways and extent of the mineralizing fluids associated with the Pering Zn-Pb deposit within the Griqualand West sub-basin. Three carbonate phases were identified within the vugs using cathodoluminescence microscopy. The first phase formed a reaction rim on the host dolomites during the deposition of sphalerite and oscillatory zoned carbonate. Finally calcite was deposited, which is associated with post-mineralizing fluids. The vug-filling carbonates have very radiogenic 87Sr/86Sr values (0.72-0.76) compared with the host dolomites (0.70-0.73). The gangue carbonate minerals deposited within the vugs have similar radiogenic 87Sr/86Sr values to the gangue minerals of the main Pering orebody, indicating that the vugs formed part of the aquifer system through which the mineralizing fluids migrated. Radiogenic 87Sr was not acquired from the surrounding host dolomite. The mineralizing fluids may have picked up radiogenic 87Sr when migrating through porous rocks such as the Makwassie Quartz Porphyry of the Ventersdorp Supergroup or felsic rocks forming the Kaapvaal Craton. In addition, radiogenic Sr may have been acquired from dewatering of the Lokammona shales within the area, or expelled from amphibolite and granulite rocks involved in the Kheis or Namaqua Tectonic events. Two models are proposed to explain the genesis of the main Pering deposit and the occurrence of sphalerite in the vug-filling carbonates surrounding the deposit: 1) Mixing Model; and 2) Single Fluid Model. The Single Fluid Model is preferred which involves a single fluid migration and interaction with the carbonate host rock and/or pore fluid. The metals were probably transported as chloride complexes together with reduced sulphur at temperatures greater than 2000 C. Deposition of the ore minerals resulted from either a dilution of the fluid, a pH increase or a temperature decrease. Both dolomites and vug-filling carbonates have a model Pb age between 2.0 and 2.7. Secondary 1Ga model ages indicate a minor Namaqua tectonic influence. Carbon and oxygen isotopes indicate that the fluids originated in a deep burial environment. Future exploration work using cathodoluminescence microscopy and staining techniques will be both useful and cost-effective. Isotopic work should concentrate on the Rb-Sr system as radiogenic 87Sr/86Sr values are the best indicators of the path of the mineralizing fluid, and the proximity to ore concentrations. / Thesis (M.Sc.)-University of Natal, 1992.

No description available.

Geologinis potencialas yra geologinių išteklių (objektų, sąlygų, reiškinių ir procesų) visuma, galinti būti šiuo metu arba perspektyvoje įtraukta į ūkinę veiklą. Sąlyginai galima skirti penkias išteklių grupes: naudingųjų iškasenų ištekliai, struktūriniai-tektoniniai ištekliai, erdviniai ištekliai, informaciniai ištekliai ir rekreaciniai ištekliai. Pagrindinis darbo tikslas - įvertinti pagrindinius Pakruojo rajono geologinio potencialo išteklius ir jų apsaugą. Siekiant jį realizuoti buvo įvertinti pagrindiniai geologinio potencialo ištekliai. Nustatyta geopaveldo objektų įvairovė ir sklaida Pakruojo rajone. Įvertinti pagrindiniai naudingųjų iškasenų ištekliai Pakruojo rajone, jų eksploatacijos mastai, apžvelgti dolomito panaudojimo galimybes Lietuvos ūkyje. Taip pat buvo svarbu įvertinti dolomito gavybos poveikį aplinkai, rekultivacijos būdus. Buvo aplankyti Petrašiūnų, Klovainių dolomito karjerai, įvertinta jų aplinkos būklė, lankymų metu bendrauta su karjerus eksploatuojančių įmonių administracija, rinkti dolomito pavyzdžiai detalesniam tyrimui, taip pat papildyti LEU geologijos kabineto dolomitų kolekciją su įvairiomis fosilijomis (koralų, pilvakojų ir kt). Statistinis metodas, naudotas apskaičiuojant įvairius naudingųjų iškasenų išteklių gavybos duomenis. Kartografinis metodas: buvo analizuojami žemėlapiai, sudaromi. Pakruojo rajone yra nedidelės struktūrinių-tektoninių ir erdvinių išteklių panaudojimo galimybės. Iš geologinio potencialo išteklių Pakruojo rajone... [toliau žr. visą tekstą] / Geological potential is geological resources (objects, conditions, events, and processes) altogether, that can be or is currently included in the economic activity. Relatively the resources can be divide in to five groups: mineral resources, the structural-tectonic stocks, spatial resources, information resources and recreational resources. The main purpose – is to evaluate the main potential geological resources and their protection in Pakruojis district. In order to realize it, the main potential geological resources were evaluated. Also the variety and dissemination of geoheritage objects were determined in Pakruojis district. In the same district, the evaluation of the main mineral resources, the scale of exploitation, and a review of the use of dolomite for the Lithuanian economy, was done. It was also important to evaluate the impact of the production of dolomite for environment and remediation techniques. The dolomite quarries of Petrašiūnai and Klovainiai were visited, their environmental conditions were evaluated. During these visits the administration of quarries operating company‘s were contacted; dolomite samples were collected for more detailed investigation. The dolomite collection of LEU Geological Study Room was complemented with the various fossils (corals, gastropods, etc.) as well. The statistical method was used for calculating the various mineral resource extraction data. Mapping method: there was analyzed maps and drawn maps. ... [to full text]