ALBERT

Description: The worldwide increasing energy demand triggered studies focused on defining the underground energy potential even in areas previously discharged or neglected. Nowadays, geological gas storage (CO 2 and/or CH 4 ) and geothermal energy are considered strategic for low-carbon energy development. A widespread and safe application of these technologies needs an accurate characterization of the underground, in terms of geology, hydrogeology, geochemistry and geomechanics. However, during pre-feasibility study-stage, the limited number of available direct measurements of reservoirs, and the high costs of reopening closed deep wells must be taken into account. The aim of this work is try to overcome these limits, proposing a new methodology to reconstruct vertical profiles, from surface to reservoir base, of: i) thermal capacity, ii) thermal conductivity, iii) porosity and iv) permeability, through integration of well-log information, petrographic observations on inland outcropping samples and, flow and heat transport modelling. As case study to test our procedure we selected a deep-structure, located in the medium Tyrrhenian Sea (Italy). Obtained results are consistent with measured data, confirming the validity of the proposed model. Notwithstanding intrinsic limitations due to manual calibration of the model with measured data, this methodology represents a useful tool for reservoir and geochemical modellers that need to define petrophysical input data for underground modelling before the well reopening. This article is protected by copyright. All rights reserved.

Description: A polyphase history of oceanic construction and consumption is documented by the distribution of the Tethyan ophiolitic suture zones in Iran. Despite the geodynamic significance of these suture zones, few modern petrological and geochronological data are available from these ophiolitic domains, hampering a full assessment of the timing, thermobaric regimes and palaeotectonic scenarios leading to oceanic suturing and continental assembly in Iran and, more in general, along the southern margin of Eurasia. In this paper, we describe a newly discovered HP ophiolite mélange within the Rasht ophiolites, at the NW termination of the Palaeo-Tethyan suture in Iran. Petrological investigations on the metamorphic units embedded within the ophiolite mélange are integrated with whole-rock geochemistry and Ar–Ar phengite geochronology to constrain the geotectonic setting of formation and to define the associated P – T – t paths. We provide evidence that the Rasht ophiolite domain corresponds to an exhumed subduction complex formed during Early Carboniferous ( c. 350 Ma) subduction of a branch of the Palaeo-Tethyan oceanic realm, with peak metamorphism equilibrated under blueschist- to eclogite-facies metamorphic conditions. Implications of these data for the palaeotectonic reconstruction during closure of the Palaeo-Tethyan ocean and the terminal collisional assembly along the southern margin of the Eurasia plate are also discussed. Supplementary material: Analytical methods and protocols are available at https://doi.org/10.6084/m9.figshare.c.3706852

Description: A polyphase history of oceanic construction and consumption is documented by the distribution of the Tethyan ophiolitic suture zones in Iran. Despite the geodynamic significance of these suture zones, few modern petrological and geochronological data are available from these ophiolitic domains, hampering a full assessment of the timing, thermobaric regimes and palaeotectonic scenarios leading to oceanic suturing and continental assembly in Iran and, more in general, along the southern margin of Eurasia. In this paper, we describe a newly discovered HP ophiolite mélange within the Rasht ophiolites, at the NW termination of the Palaeo-Tethyan suture in Iran. Petrological investigations on the metamorphic units embedded within the ophiolite mélange are integrated with whole-rock geochemistry and Ar–Ar phengite geochronology to constrain the geotectonic setting of formation and to define the associated P – T – t paths. We provide evidence that the Rasht ophiolite domain corresponds to an exhumed subduction complex formed during Early Carboniferous ( c. 350 Ma) subduction of a branch of the Palaeo-Tethyan oceanic realm, with peak metamorphism equilibrated under blueschist- to eclogite-facies metamorphic conditions. Implications of these data for the palaeotectonic reconstruction during closure of the Palaeo-Tethyan ocean and the terminal collisional assembly along the southern margin of the Eurasia plate are also discussed. Supplementary material: Analytical methods and protocols are available at https://doi.org/10.6084/m9.figshare.c.3706852

Description: The worldwide increasing energy demand triggered studies focused on defining the underground energy potential even in areas previously discharged or neglected. Nowadays, geological gas storage (CO2 and/or CH4) and geothermal energy are considered strategic for low-carbon energy development. A widespread and safe application of these technologies needs an accurate characterization of the underground, in terms of geology, hydrogeology, geochemistry, and geomechanics. However, during prefeasibility study-stage, the limited number of available direct measurements of reservoirs, and the high costs of reopening closed deep wells must be taken into account. The aim of this work is to overcome these limits, proposing a new methodology to reconstruct vertical profiles, from surface to reservoir base, of: (i) thermal capacity, (ii) thermal conductivity, (iii) porosity, and (iv) permeability, through integration of well-log information, petrographic observations on inland outcropping samples, and flow and heat transport modeling. As case study to test our procedure we selected a deep structure, located in the medium Tyrrhenian Sea (Italy). Obtained results are consistent with measured data, confirming the validity of the proposed model. Notwithstanding intrinsic limitations due to manual calibration of the model with measured data, this methodology represents an useful tool for reservoir and geochemical modelers that need to define petrophysical input data for underground modeling before the well reopening. © 2016. American Geophysical Union. All Rights Reserved.

Description: The worldwide increasing energy demand triggered studies focused on defining the underground energy potential even in areas previously discharged or neglected. Nowadays, geological gas storage (CO2 and/or CH4) and geothermal energy are considered strategic for low-carbon energy development. A widespread and safe application of these technologies needs an accurate characterization of the underground, in terms of geology, hydrogeology, geochemistry and geomechanics. However, during pre-feasibility study-stage, the limited number of available direct measurements of reservoirs, and the high costs of reopening closed deep wells must be taken into account. The aim of this work is try to overcome these limits, proposing a new methodology to reconstruct vertical profiles, from surface to reservoir base, of: i) thermal capacity, ii) thermal conductivity, iii) porosity and iv) permeability, through integration of well-log information, petrographic observations on inland outcropping samples and, flow and heat transport modelling. As case study to test our procedure we selected a deep-structure, located in the medium Tyrrhenian Sea (Italy). Obtained results are consistent with measured data, confirming the validity of the proposed model. Notwithstanding intrinsic limitations due to manual calibration of the model with measured data, this methodology represents a useful tool for reservoir and geochemical modellers that need to define petrophysical input data for underground modelling before the well reopening.

Description: Published

Description: 4534-4552

Description: 1TR. Studi per le Georisorse

Description: JCR Journal

Description: The Siah-Kamar Mo deposit (SKMD) is located at the northwestern termination of the Urumieh-Dokhtar magmatic zone and it is the only porphyry Mo ore reserve in Iran. The exploration program documented 39.2 Mt proved reserves @ 539 ppm Mo and 66.4 Mt probable reserves @ 266 ppm Mo. In this study, field and petrographic investigations, integrated with geochemical (fluid inclusion and quartz chemistry) and geochronological (U-Pb zircon, Re-Os molybdenite, and Rb-Sr multimineral isochron) studies are used to propose a metallogenic model for the Mo mineralisation in the SKMD. The geology of the SKMD is characterized by the emplacement of a multiphase Oligocene basic/intermediate (at ca. 33–30 Ma) to acidic (29–28 Ma) magmatic suite, which intruded the Eocene volcanic country rocks. The alteration zone, about 4 × 3 km in size and with a general NW-SE trend, is centered within the main basic porphyry stock, grading from an inner potassic-sodic zone to peripheral phyllic/propylitic halos. The late acidic magmatic products (stocks and dykes) intruded and post-dated the main alteration zone. Two-stage Mo mineralisation is recognised, including: (i) stage-1, disseminated molybdenite, coeval with the formation of potassic-sodic alteration and minor, microscale Fsp, Bt, Qz + Po veinlets; and (ii) stage-2, high-grade molybdenite + carbonate (±sericite), structurally-controlled stockwork veining. Fluid inclusion systematics combined with TitaniQ thermometry documents a mineralising fluid system compatible with a transition from high-temperature (up to ca. 600 °C) magmatic to epithermal (250 °C) conditions during progressive cooling, exhumation and mixing with meteoric sources at shallow crustal conditions (ca. 7–3 km). The Re-Os molybdenite dating constrains the high-grade Mo ore formation at ca. 29–28 Ma, attesting for the intimate linkage between the main Mo mineralisation and the acidic magmatic phase in the area. The Rb-Sr geochronology of the potassic-sodic alteration zones confirms the two-stage magmatic/mineralisation scenarios, overlapping within errors with the results obtained from the U-Pb zircon geochronology and constraining the formation of the potassic-sodic and phyllic alteration at ca. 33 and 28 Ma, respectively. Our results document an uncommon scenario of two-stage porphyry Mo mineralisation associated with intensive late stage carbonate precipitation and achieved during a long-lasting and multiphase magmatic pulses of Oligocene age. We highlight the dominant role of acidic fluid neutralisation for further ore enrichment during polyphase magma intrusion as the dominant factor controlling the Mo mineralisation in the SKMD. Comparison at a regional-scale indicates that parameters such as longevity of magma supply, progressive magma crystallization/differentiation, and the presence of a possible pre-enriched crustal material should be considered responsible for the Mo endowment in the UDMZ.

Description: The Menderes Massif of western Turkey is a key area to study feedback relationships between magma generation/emplacement and activation of extensional detachment tectonics. Here, we present new textural analysis and in situ U–(Th)–Pb titanite dating from selected samples collected in the transition from the undeformed to the mylonitized zones of the Salihli granodiorite at the footwall of the Neogene, ductile-to-brittle, top-to-the-NNE Gediz–Alaşheir (GDF) detachment fault. Ductile shearing was accompanied by the fluid-mediated sub-solidus transformation of the granodiorite to orthogneiss, which occurred at shallower crustal levels and temperatures compatible with the upper greenschist-to-amphibolite facies metamorphic conditions (530–580 °C and P 〈 2 GPa). The syn-tectonic metamorphic overgrowth of REE-poor titanite on pristine REE-rich igneous titanite offers the possibility to constrain the timing of magma crystallisation and solid-state shearing at the footwall of the Gediz detachment. The common Pb corrected 206Pb/238U (206Pb*/238U) ages and the REE re-distribution in titanite that spatially correlates with the Th/U zoning suggests that titanite predominantly preserve open-system ages during fluid-assisted syn-tectonic re-crystallisation in the transition from magma crystallization and emplacement (at ~ 16–17 Ma) to the syn-tectonic, solid-state shearing (at ~ 14-15 Ma). A minimum time lapse of ca. 1–2 Ma is then inferred between the crustal emplacement of the Salihli granodiorite and nucleation of the ductile extensional shearing along the Gediz detachment. The reconstruction of the cooling history of the Salihli granodiorite documents a punctuated evolution dominated by two episodes of rapid cooling, between ~ 14 Ma and ~ 12 Ma (~ 100 °C/Ma) and between ~ 3 and ~ 2 Ma (~ 105 °C/Ma). We relate the first episode to nucleation and development of post-emplacement of ductile shearing along the GDF and the second to brittle high-angle faulting, respectively. Our dataset suggests that in the Menderes Massif the activation of ductile extension was a consequence, rather than the cause, of magma emplacement in the extending crust.

Description: The Eastern Cordillera of Colombia rose to maximum elevations of 〉5 km during the Cenozoic by inversion of a Mesozoic rift basin. Previous studies proposed that the exhumation of the Eastern Cordillera increased from ~6 Ma to the present due to the interplay between tectonic shortening and climate. In this study, we integrate new field observations, structural data, low-temperature thermochronology, thermobarometry, and vitrinite reflectance along a section through the Tablazo, Cocuy, and Llanos regions to estimate the amount of shortening and the exhumation history. Our results indicate that shortening started as early as the latest Maastrichtian-Paleocene in the Tablazo and Cocuy regions. Exhumation migrated eastward, starting in the Paleocene in the west and continuing in the Miocene in the east. The amount and rate of exhumation peaked in the Cocuy region with values of 〈5 km and 〈 0.4 km/Ma, respectively. At the highest elevations in the Cocuy Sierra, we also found evidence of a low-pressure/high-temperature metamorphic overprint, possibly related to shallow and local magmatic intrusions that occurred in the Late Miocene. Our cross-section interpretation suggests a low amount of shortening (13%) that is mainly accommodated by high-angle inverted faults and by the frontal thrust system. The presence of shallow magmatic bodies, moderate exhumation, and low shortening raises questions about the processes (isostatic versus dynamic) that drove the topographic growth of the high Cocuy Sierra.