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In southern Tuscany (central Italy), deep to shallow geothermal systems were active since the Pleistocene and comprise fluids carrying variable amounts of CO2. The Monte Amiata geothermal fields include two main reservoirs: a deep one located in the Palaeozoic metamorphic succession (1300–3000 m deep) belonging to the Tuscan metamorphic ‘basement’ and a shallow one hosted in the Mesozoic sedimentary...
At White Pine, the stratiform sedimentary copper (SSC) mineralization occurs mostly as chalcocite in gray‐black shales in the basal approximately 6 m of the 1081 ± 9 Ma Nonesuch Formation of the Keweenawan Supergroup. Paleomagnetic analysis of 176 specimens (19 sites) isolated collinear characteristic remanent magnetization (ChRM) directions in both magnetite and hematite in both the oxidized SSC...
Sierra de Gádor is a complex, Triassic age aquifer system formed by dolostones and limestones with interbedded gypsum. On top, a thick Neogene‐Quaternary series gives rise to shallow aquifers. F‐Pb‐Zn stratabound deposits are found within the Triassic carbonate formations. Their mineral paragenesis includes sphalerite, galena, pyrite, marcasite, fluorite and barite. The Sierra de Gádor groundwater...
A regional study on late burial, syntectonic dolomites and syntectonic calcite and quartz veins occurring in the hemipelagic Triassic–Jurassic succession of the Lagonegro Basin (southern Apennines) was carried out by integrating fieldwork with structural, fluid inclusion, and geochemical investigations on both surface and subsurface samples. The main goal was to characterize the different parent fluids,...
Dedolomitization or calcitization, the replacement of dolomite by calcite, modifies the porosity and permeability of carbonate rocks. This study evaluates the effects of dedolomitization on the porosity of carbonates by means of geochemical and reactive transport simulations. The obtained results indicate that dedolomitization is a slow process that may be triggered by cold meteoric water but also...
An increasing need exists to quantify the impact of diagenesis on complex and heterogeneous geological reservoirs and to predict the related field‐scale porosity‐permeability distribution. Development of approaches to quantify diagenetic events is an important step towards the construction of integrated numerical reservoir models predicting the impact of successive diagenetic events on petrophysical...
Fluid inclusions from two quartz samples of the McArthur River and Rabbit Lake unconformity‐related uranium deposits (Athabasca Basin, Canada) were analysed by synchrotron X‐ray fluorescence (SXRF) and X‐ray absorption near‐edge spectroscopy (XANES) to shed light on (i) the detailed chemistry of the fluids having transported the uranium and (ii) the speciation of uranium in these fluids. The analysed...
The Lower Saxony Basin (LSB) in northwest Germany is one of the oldest oil‐producing basins in the world, where the first production well was drilled in 1864. It has been intensively investigated with respect to its hydrocarbon potential and can be regarded as a well‐studied example of a sedimentary basin that experienced strong inversion and uplift. Oil and gas source rocks of economic importance...
The upper Burdigalian Vilobí Gypsum Unit, located in the Vallès Penedès half‐grabben (NE Spain), consists of a 60‐m thick succession of laminated‐to‐banded secondary and primary gypsum affected by Neogene extension in the western part of Mediterranean Sea. This Tertiary extensional event is recorded in the evaporitic unit as six fracture sets (faults and joints), which can be linked with basin‐scale...
Laverton is an important region in the Yilgarn Craton for gold mineralization. Previous studies suggested that the premineralization structure was dominated by a fault restraining step‐over structure with the Wallaby fault and Sunrise Shear Zone as the key fault splays hosting the world‐class Wallaby and Sunrise Dam gold deposits, respectively. Two major gold mineralization phases occurred during...
The time series of two continuously operating gas monitoring stations at Oldřišská and Nový Kostel located along seismoactive faults in the epicentral area of the NW Bohemian swarm earthquakes (Czech Republic) are compared with water level fluctuations in two boreholes positioned along these faults and with gas flux variations of a mofette at the Soos mofette field at 9 km distance. The seasonal trend...
Accurate reconstruction of diagenetic P‐T conditions in petroleum reservoirs from fluid inclusion data relies on valid measurements of methane concentration in aqueous inclusions. Techniques have been developed (Raman spectrometry) to provide sufficiently accurate data, assuming measured methane concentration has not been modified after aqueous inclusion entrapment. This study investigates the likelihood...
The most important petroleum exploration target in the Tarim Basin, northwest China, is the paleokarst reservoir. To understand the source and evolution of brine in this type of reservoir, a total of 37 formation‐water samples were collected from the Middle‐Lower Ordovician paleokarst reservoir in the Lunnan oilfield. The δD‐δ18O correlation and Cl/Br ratios reflect the mixture of two fluids: meteoric...
Cataclastic deformation bands, which are common in sandstone reservoirs and which may negatively affect fluid flow, are generally associated with notable thickness variations. It has been suggested previously that such thickness variations represent an important control on how deformation bands affect fluid flow. The effects of such thickness variations are tested in this study though statistical...
Geologic carbon capture and storage (CCS) is an option for reducing CO2 emissions, but leakage to the surface is a risk factor. Natural CO2 reservoirs that erupt from abandoned oil and gas holes leak to the surface as spectacular cold geysers in the Colorado Plateau, United States. A better understanding of the mechanisms of CO2‐driven cold‐water geysers will provide valuable insight about the potential...
This manuscript addresses the topic of transverse dispersion and its impact on the behavior of the saturated zone below Yucca Mountain, a site that had been proposed for a US nuclear waste repository. Guided by a review of relevant observations of dispersion in similar formations, this study evaluates the importance of uncertainty in dispersion, particularly dispersion transverse to the mean transport...
Monazite (CePO4) and xenotime (YPO4) are important accessory minerals in metasediments. They host significant rare earth elements (REE) and are useful for geochronology and geothermometry, so it is essential to understand their behavior during the metasomatic processes that attend high‐grade metamorphism. It has been proposed that F‐bearing fluids enhance solubility and mobility of REE and Y during...
Numerical simulations of multiphase CO2 behavior within faulted sandstone reservoirs examine the impact of fractures and faults on CO2 migration in potential subsurface injection systems. In southeastern Utah, some natural CO2 reservoirs are breached and CO2‐charged water flows to the surface along permeable damage zones adjacent to faults; in other sites, faulted sandstones form barriers to flow...
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