Elemental geochemistry to complement stable isotope data of fossil travertine: Importance of digestion method and statistics

Journal of Hazardous Materials

Cappuyns

et al. 2021

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Continental carbonates and their springs are rarely investigated as a source of toxicity. Remarkably high contents of As (up to 10 g/kg) have been found in travertine deposits and associated spring waters, nearby Ghorveh city (western Iran). Two types of travertines were distinguished: (i) Fissure ridge travertines, in areas with a carbonate-dominated basement, are characterized by a relatively low As content (<15 mg/kg) and low As leaching. Their spring waters contain >150 µg/L of As; (ii) Mound travertines, rich in noncarbonate impurities, occur in areas with volcanic substrates and contain high As concentrations (on average ~1500 mg/kg) with high leachability. Their spring waters have lower As concentrations than equivalent fissure ridge waters. Principal Component Analyses of the elemental and mineralogical composition show the unstable association of As over a wide range of pH values to non-carbonate related elements, in particular iron, related to clay minerals. The high potential release of As may result in adverse ecotoxicological effects in surrounding agricultural soils and crops. An ecological risk assessment, based on enrichment factors and risk indices, confirms the enrichment and very high potential ecological risk of As around mound carbonates. The human health risk assessment based on calculation via exposure factors suggests adverse non-carcinogenic and high carcinogenic risk with regard to As, both for adults and children. However, further investigations are necessary to evaluate the real ecological and human health risks.

Section: Statistical Analysesmentioning

confidence: 99%

High geogenic arsenic concentrations in travertines and their spring waters: Assessment of the leachability and estimation of ecological and health risks

Mohammadi

Journal of Hazardous Materials

Cappuyns

et al. 2021

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“…Stable isotopes of oxygen (δ 18 O), carbon (δ 13 C) and strontium ( 87 Sr/ 86 Sr) and major and trace elements Ca, Al, Fe, K, Mg, Na, P, Sr, S and Ba were analysed to characterize the origin of mineralizing fluids. This selection of elements was based on Teboul et al (2016) and Claes et al (2019). Powders for stable isotope analyses were extracted using a dental drill with a diameter of approximately 1 mm, which was cleaned using distilled and ultrapure water.…”

Section: Geochemistry (Stable Isotopes and Trace Elements) And Mineralogymentioning

confidence: 99%

“…Trace element analysis was performed on a set of 17 powdered samples, dissolved by four acid digestion to ensure dissolution of all mineral phases (Claes et al, 2019). These four acids were 65 % sub-boiled HNO3, 70 % HClO4, 48 % sub-boiled HF and 2.5 M HCl.…”

Section: Geochemistry (Stable Isotopes and Trace Elements) And Mineralogymentioning

confidence: 99%

“…"Thermogene", "endogene" or "hypogean" spring carbonates, referred to as travertine (sensu Capezzuoli et al, 2014), are formed due to CO2 and source fluids having a deep origin, whereas "meteogene", "epigenic" or "epigean" spring carbonates, referred to as tufa (sensu Capezzuoli et al, 2014), are formed with CO2 of shallow origin from soil biodegradation, plants or the atmosphere (Pentecost, 2005;Crossey et al, 2006;Teboul et al, 2016). Deducing the origin of CO2 and palaeofluid provenance are thus essential for classifying spring carbonates and understanding drivers and processes through time, but also have greater implications with regard to precipitation processes, rock textures, mineralogy, associated biota and palaeohydrology (Minissale, 2004;Pentecost, 2005;Crossey et al, 2006;Teboul et al, 2016;Claes et al, 2019). Geochemical element, stable and radiogenic isotope data are the ultimate tools in deducing fluid characteristics, origin of Ca 2+ and CO2, fluid source rocks and reconstructing the palaeohydrology of ancient spring systems (Minissale et al, 2002;Minissale, 2004;Teboul et al, 2016;Claes et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

“…Deducing the origin of CO2 and palaeofluid provenance are thus essential for classifying spring carbonates and understanding drivers and processes through time, but also have greater implications with regard to precipitation processes, rock textures, mineralogy, associated biota and palaeohydrology (Minissale, 2004;Pentecost, 2005;Crossey et al, 2006;Teboul et al, 2016;Claes et al, 2019). Geochemical element, stable and radiogenic isotope data are the ultimate tools in deducing fluid characteristics, origin of Ca 2+ and CO2, fluid source rocks and reconstructing the palaeohydrology of ancient spring systems (Minissale et al, 2002;Minissale, 2004;Teboul et al, 2016;Claes et al, 2019). In addition, fluid inclusion studies can provide direct information about the origin, temperature and subsurface interaction of travertine precipitating fluids (Słowakiewicz, 2003;El Desouky et al, 2015;Rimondi et al, 2015;Capezzuoli et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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Fossil travertine system and its palaeofluid provenance, migration and evolution through time: Example from the geothermal area of Acquasanta Terme (Central Italy)

Janssens

Capezzuoli

et al. 2020

Sedimentary Geology

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The geothermal area of Acquasanta Terme has often been studied for its active and fossil travertine deposits to elucidate fluid origin, geodynamic and hydrological setting. Even though present-day thermal springs are usually used to obtain most information, the three travertine terraces bordering the Tronto river contain a plethora of information. A combination of elemental and isotope analyses (δ 18 O, δ 13 C and 87 Sr/ 86 Sr-ratio), fluid inclusion microthermometry and U-Th dating is used to verify the hydrogeology and its timing. These analyses point out two fluid reservoirs with distinctly different fluids, one with low salinity of 0.7 wt% NaCl eq. and another with 28.5 wt% NaCl eq., which corresponds to the fluid composition of present-day spring fluids. Furthermore, it is demonstrated that geothermal sources were intermittently active in the past 221 ka mainly during uneven-numbered marine isotope stages, which are related to humid, interglacial periods and resulted in three different travertine terraces around 210.5, 126.5, and 36.5 ka. Accordingly, an uplift rate for this area could be estimated at around 1 mm/ka. The fluids were tapped at a depth of approximately 3 km in the tectonized, cataclastic fraction of the Triassic Anidriti di Burano Formation, the Calcare Cavernoso Formation and are originally meteoric based on geochemical evidence of a uniform 87 Sr/ 86 Sr-ratio of 0.707914 ± 0.00019 and a δ 18 Oaragonite value of -11.90 ± 0.34 ‰, which has been depressed by elevated precipitation temperatures between 22.2 and 50 °C. The characterization and dating of fossil travertine deposits gives valuable data providing insights in long-term fluid flow and orogenic uplift rates, adding valuable information to present-day spring fluid characterization.

Unravelling the pore network and its behaviour: An integrated NMR, MICP, XCT and petrographical study of continental spring carbonates from the Ballık area, SW Turkey

Soete

The Depositional Record

et al. 2021

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Applying an integrated methodology, including petrography, mercury injection capillary pressure, laboratory nuclear magnetic resonance and X‐ray computed tomography, on continental spring carbonate reservoir analogue samples is a prerequisite to understand plug scale porosity and permeability heterogeneities. Depending on the dominant pore type in a sample, the orientation and distribution of the pores, pore network connectivity varies from poor to excellent in these continental spring carbonates. The latter exhibit large‐scale ranges for both porosity (3%–25%) and permeability (0.004–3,675 mD). Facies classification alone proved insufficient to link porosity and permeability, due to intrafacies pore network variability. Better assessment of reservoir properties can be achieved by subdividing facies into lithotype and pore type classes. Obtained pore network data addresses the pore types, pore (throat) sizes, number of pore compartments, and allow a subdivision of the pore size distributions into unimodal, bimodal and atypical types. There is no micropore compartment present in samples with unimodal mercury injection capillary pressure and nuclear magnetic resonance distributions. Decoupled micropore compartments are observed in samples with bimodal mercury injection capillary pressure and nuclear magnetic resonance distributions, which show isolating calcite rims, and have limited permeabilities. The cement rims decrease the macropore connectivity and decouple the micropore compartments, which reside in micritic dendrites. The micropore compartment (r < 1 µm) is coupled with the mesopore (r = 1–15 µm) and macropore compartment (r > 15 µm) for atypical samples which lack pore‐lining calcite rims.