Insights into mantle-type volatiles contribution from dissolved gases in artesian waters of the Great Artesian Basin, Australia

The geochemical features of the volatiles dissolved in artesian thermal waters discharged over three basins (Millungera, Galilee and Cooper basin) of the Australian Great Artesian Basin (GAB) consistently indicate the presence of fluids from multiple gas sources located in the crust (e.g. sediments, oil reservoirs, granites) as well as minor but detectable contributions of mantle/magma-derived fluids. The gases extracted from 19 water samples and analyzed for their chemical and isotopic composition exhibit amounts of CO up to about 340mlSTP/L marked by a δC (Total Dissolved Carbon) ranging from -16.9 to +0.18‰ vs PDB, while CH concentrations vary from 4.4×10 to 4.9mlSTP/L. Helium contents were between 9 and >2800 times higher than equilibrium with Air Saturated Water (ASW), with a maximum value of 0.12mlSTP/L. Helium isotopic composition was in the 0.02-0.21 Ra range (Ra = air-normalized He/He ratio). The three investigated basins differ from each other in terms of both chemical composition and isotopic signatures of the dissolved gases whose origin is attributed to both mantle and crustal volatiles. Mantle He is present in the west-central and hottest part of the GAB despite no evidence of recent volcanism. We found that the partial pressure of helium, significantly higher in crustal fluids than in mantle-type volatiles, enhances the crustal He signature in the dissolved gases, thus masking the original mantle contribution. Neotectonic activity involving deep lithospheric structures and magma intrusions, highlighted by recent geophysical investigations, is considered to be the drivers of mantle/magmatic volatiles towards the surface. The results, although pertaining to artesian waters from a vast area of >542,000km, provide new constraints on volatile injection, and show that fluids' geochemistry can provide additional and independent information on the geo-tectonic settings of the Great Artesian Basin and its geothermal potential

La disclosure volontaria del modello di business nel prospetto informativo di quotazione: un’analisi comparative

How do companies to be listed actually deal with voluntary disclosure of their business model? Is it true that firms with greater knowledge-based resources and technological innovation endowments have a lower propensity to adopt fully open communication behaviors? This paper aims to identify the voluntary disclosure policies adopted by three Italian companies in their Initial Public Offering (IPO) prospectuses in order to investigate whether any differences may depend on the type of innovation underlying each business model. A series of interviews conducted with the top management made it possible to understand more deeply the business model of each company. Further, a content analysis has been developed to compute a measure of disclosure and to point out the strategic concepts and their relevance. We provide evidence that companies with a business model based on technology-push innovation have a lower propensity to the full disclosure of their intangible components, particularly of those mainly based on knowledge as these are also invisible. Our study adds to the literature of business and financial reporting by focusing on a new object of inquiry, that is the business model. The business model plays an important role in allowing external actors to understand a company’s value, thus companies’ strategic communication should be shaped accordingly. The results suggest the need to address the issue of voluntary disclosure of the business model by first distinguishing “visible” intangible resources from those that are “invisible” (both to financial and competitive markets). The study aims to make a contribution to the ongoing debate on business and financial reporting practice

Insights into mantle-type volatiles contribution from dissolved gases in artesian waters of the Great Artesian Basin, Australia

The geochemical features of the volatiles dissolved in artesian thermal waters discharged over three basins (Millungera, Galilee and Cooper basin) of the Australian Great Artesian Basin (GAB) consistently indicate the presence of fluids from multiple gas sources located in the crust (e.g. sediments, oil reservoirs, granites) as well as minor but detectable contributions of mantle/magma-derived fluids. The gases extracted from 19 water samples and analyzed for their chemical and isotopic composition exhibit amounts of CO2 up to about 340 mlSTP/LH2O marked by a δ13CTDC (Total Dissolved Carbon) ranging from −16.9 to +0.18‰ vs PDB, while CH4 concentrations vary from 4.4 × 10−5 to 4.9 mlSTP/LH2O. Helium contents were between 9 and N2800 times higher than equilibrium with Air Saturated Water (ASW), with a maximum value of 0.12 mlSTP/LH2O. Helium isotopic composition was in the 0.02–0.21 Ra range (Ra = air-normalized 3He/4He ratio). The three investigated basins differ from each other in terms of both chemical composition and isotopic signatures of the dissolved gases whose origin is attributed to both mantle and crustal volatiles. Mantle He is present in the west-central and hottest part of the GAB despite no evidence of recent volcanism.Wefound that the partial pressure of helium, significantly higher in crustal fluids than in mantle-type volatiles, enhances the crustal He signature in the dissolved gases, thus masking the original mantle contribution. Neotectonic activity involving deep lithospheric structures and magma intrusions, highlighted by recent geophysical investigations, is considered to be the drivers of mantle/magmatic volatiles towards the surface. The results, although pertaining to artesian waters froma vast area of N542,000 km2, provide newconstraints on volatile injection, and showthat fluids' geochemistry can provide additional and independent information on the geo-tectonic settings of the Great Artesian Basin and its geothermal potential

Hydrogeology of an arsenic-mineralized fractured phyllite and implications for groundwater arsenic dispersion

The hydrogeology of the Paracatu area in Minas Gerais, Brazil, was assessed by a combination of pumping tests, natural hydrogeological tracers (oxygen and hydrogen stable isotopes, and Rn), and trace element water geochemical analyses. The area's geological basement is a fractures phyllite hosting a significant gold deposit, with gold being associated with arsenopyrite and quartz boudins. Hydraulic conductivity in both mineralized and non-mineralized areas was low, ranging from 2 × 10- to 1 × 10- cm/sec. Pervasive kaolinite filling was observed in the fractures. Rn levels were very variable, ranging from ∼8 to ∼110 Bq/L, and stable isotope data also indicated multiple water sources and complex mixing patters. Arsenic levels were typically below 1 μg/L, with some exceptions found in both impacted and non-impacted areas. Despite the fracturing and jointing, the geological substrate has low hydraulic permeability, limiting the mobility of As released from the rock mineralization. Extensive analytical results have confirmed the good quality of groundwater in the Paracatu region

Magmatism of the eastern Red Sea margin in the northern part of Yemen from Oligocene to present

The northern part of Yemen during the last 30 Ma has been the site of an intense magmatic activity which can be divided into three main episodes. The first episode lasted from 30 to 18 Ma and was characterized by two climaxes. Huge flood basalt eruptions between 30 to 26 Ma were succeeded by massive ignimbrite sheet deposits and intrusion of silicic subvolcanic masses 22 to 20 Ma ago. Contemporaneously, along the present-day western margin of the Yemen Plateau a basaltic dike swarm was emplaced. Additionally, alkaline and peralkaline granites were intruded at the end of the first climax and throughout the second. After a long quiescence, magmatic activity occurred again in Late Miocene time (about 10 Ma) with extrusion of lava flows in scattered areas (e.g. Al Harf, Wadi As Sirr, Maswar Al Hada, Jabal An Nar). The third magmatic episode has been concentrated in three well defined areas. It began about 6.5 Ma ago in the Dhamar Rada area and later in the San'a Amram and Sirwah Marib areas. New chemical and isotopic data on the magmatic products of North Yemen indicate that extensive crustal contamination, together with simple crystal fractionation processes, have been operating during the magmatic evolution. The most primitive products of each of the three episodes share isotopic and petrological features suggesting a similar mantle source. Isotope geochemistry indicates an important asthenospheric component in the mantle source for the magmas of all three episodes. Finally, a comparison between the coeval igneous rocks of the Yemen and Ethiopia plateaus is attempted

Health risk assessment of arsenic in a residential area adjoining to a gold mine in Brazil

Paracatu is a town adjoining to a gold mine in Minas Gerais, Brazil where we collected drinking water and soil/dust samples were collected from seven residential locations. Fifteen common food categories were also collected from local vendors and stores. Arsenic was analysed by ICP-MS. A physiologically based extraction test for bioaccessibility (BAc) of arsenic was conducted on the soil/dust samples. Water arsenic ranged from non-detected to 3.9 μg/L; soil arsenic 6-461 mg/kg in th

Geological map of Capraia Island (Italy): Application of UBSU to a Miocene volcano

We present the results of a multidisciplinary study on the volcanic succession outcropping on the island of Capraia, located in the Northern Tyrrhenian Sea about half-way between Corsica and mainland Italy. This island occupies a key position for the understanding of the opening of the Tyrrhenian Sea and of the geodynamic evolution of the Northern Apennines. The starting point for this study was the reconstruction of the volcanic succession and the completion of the 1:10,000 geological map. Fieldwork was carried out at a 1:5,000 scale using lithostratigraphic units, usually formation in rank. This was necessary due to geological complexity and poor exposure, with outcrops located often along deep scarps. Detailed stratigraphic sections were logged along the west coast of the island, where a vertical section through the volcanic successions could be recognised. Where significant and widespread unconformity surfaces were recognised, UBSU (Unconformity Bounded Stratigraphic Unit) was used to group the numerous lithostratigraphic units identified during fieldwork and to reconstruct the volcanic evolution of the island. The most important unconformity may identify two volcanic successions that differ in age, eruptive style, petrography, and geochemistry. Morphological, petrographic, geochemical, and radiometric studies have been integrated with stratigraphic fieldwork to reconstruct the volcanic evolution of Capraia. The whole sets of data have been integrated in a geological database that allows complex analysis of spatial and temporal relationship taking into account different kind and rank of stratigraphical units. The bulk of the island formed between 7.55 and 7.16 Ma during separate stages, with calcalkaline lava flows and domes products, and a peak between 7.55 and 7.44 Ma. Three important unconformity surfaces were recognised in the field, all related to a hiatus in the volcano activity, style changes, and flank collapse. After a period of quiescence between 7.16 and 4.63 Ma, activity resumed at 4.63 Ma, with the eruption of shoshonites from a monogenic centre in the southern part of the island. Besides its importance for the reconstruction of volcanic events on Capraia, this study provides some temporal constrains on the geodynamic evolution of the Northern Tyrrhenian Sea and the Northern Apennines