Browsing by Author "García-Veigas, J"

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    Ca-SO4 crossover points in Phanerozoic seawater: evidence from fluid inclusions in halite
    (American Geophysical Union (AGU), 2021-12-15) Weldeghebriel, MF; Lowenstein, TK; García-Veigas, J; Cendón, DI
    The major ion (Mg2+, Ca2+, Na+, K+, SO42-, Cl-, HCO3-) chemistry of seawater has varied in the Phanerozoic and Neoproterozoic. Transitions between SO4-rich and Ca-rich seas, here called “Ca2+- SO42- crossover points” are of great biogeochemical interest because of their coincidence with shifts in seawater Mg2+/Ca2+ ratio and the mineralogies of potash evaporites. Crossover periods occurred four times over the past 550 Myr, when seawater chemistry shifted from Ca-rich to SO4-rich or vice versa. Here, chemical analyses of 2,466 fluid inclusions in marine halite define paleoseawater [Ca2+] and [SO42-] over the past 550 Myr, with emphasis on Ca2+- SO42- crossover periods. Three types of brine chemistries are recognized from [SO42-] and [Ca2+] concentrations: (1) SO4-rich (SO4>>Ca): inclusions with measurable SO42- (7-993 mmol/kg H2O, here termed mmolal) and low Ca2+ (<91 mmolal) (Late Neoproterozoic, Permian, Triassic, and Late Cenozoic); (2) Ca2+-rich (Ca >>SO4): inclusions with measurable Ca2+ (150-2000 mmolal) and very low SO42-, below detection (Cambrian, Silurian, Devonian, Mississippian, Pennsylvanian, Jurassic, and Cretaceous); (3) crossover periods (SO4≈Ca): inclusions have measurable but low concentrations of both Ca2+ (10-120 mmolal) and SO42- (10-210 mmolal) (Late Triassic to Early Jurassic, Eocene to Oligocene). The Late Pennsylvanian Paradox Formation represents a second type of crossover period. In that case, fluid inclusions vary from Ca2+-rich (3-670 mmolal) to SO4-rich (6-590 mmolal).The fourth transition from SO4-rich to Ca-rich seawater occurred during the Terminal Proterozoic to the Early Cambrian (ca. 544-515 Ma) (Brennan et al., 2004). Salts predicted to precipitate during evaporation of crossover periods, for example Eocene and Oligocene seawater are calcite, gypsum, halite, polyhalite, sylvite, carnallite, kieserite, and bischofite. The four crossover points parallel major transitions in: (1) Mg2+/ Ca2+ ratio of seawater; (2) aragonite and calcite seas; (3) MgSO4 and KCl potash evaporites; and (4) icehouse and greenhouse climates, suggesting a link between the composition of seawater, marine potash evaporites, carbonate mineralogy, and climate.
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    [Ca2+] and [SO2- 4] in Phanerozoic and terminal Proterozoic seawater from fluid inclusions in halite: the significance of Ca-SO4 crossover points
    (Elsevier, 2022-09-15) Weldeghebrial, MF; Lowenstein, TK; García-Veigas, J; Cendón, DI
    Chemical analyses of 2,618 (1,640 new and 978 published) fluid inclusions in marine halite were used to define paleoseawater [Ca2+] and [SO2- 4] over the past 550 million years (Myr). Three types of fluid inclusion brine chemistries were recognized based on measured [Ca2+] and [SO2- 4]: (1) SO4-rich with [SO2- 4] ≫ [Ca2+]; (2) Ca-rich with [Ca2+] ≫ [SO2- 4]; and (3) Ca-SO4 crossover points with [Ca2+] ≈ [SO2- 4]. The SO4-rich and Ca-rich fluid inclusion chemistries oscillated twice in the terminal Proterozoic and Phanerozoic. Transitions between SO4-rich and Ca-rich seas, here called "Ca2+ -SO2- 4 crossover points” occurred four times: terminal Proterozoic–Early Cambrian (544–515 Ma), Late Pennsylvanian (309–305 Ma), Triassic–Jurassic boundary (∼200 Ma), and Eocene–Oligocene (36–34 Ma). New fluid inclusion analyses using laser ablation-inductively coupled plasma-mass spectrometry better defined the [Ca2+] and [SO2- 4] in seawater at the Late Pennsylvanian and Eocene–Oligocene crossover points and the timing of the Triassic–Jurassic crossover point. Crossover points coincide with shifts in seawater Mg2+/Ca2+ ratios, the mineralogies of marine non-skeletal carbonates and shell building organisms (aragonite vs. calcite) and potash evaporites (MgSO4 vs. KCl types). Phanerozoic and terminal Proterozoic trends in seawater [Ca2+] and [SO2- 4] also coincide with supercontinent breakup, dispersal, and assembly cycles, greenhouse–icehouse climates, and modeled atmospheric ρCO2. Paleoseawater [Ca2+] and [SO2- 4] were calculated from the fluid inclusion data using the assumption that the [Ca2+] × [SO2- 4] ranged from 150 to 450 mmolal2, which is 0.5–1.5 times the [Ca2+] = 11 × [SO2- 4] = 29 product in modern seawater (319 mmolal2). Two additional end-member scenarios, independent of the [Ca2+] × [SO2- 4] = 150–450 mmolal2 assumption, were tested using constraints from fluid inclusion [Ca] and [SO4]: (1) constant [SO2- 4] = 29 mmolal as in modern seawater, and variable [Ca2+], and (2) constant [Ca2+] = 11 mmolal as in modern seawater and variable [SO2- 4]. Mg2+/Ca2+ ratios calculated from the three scenarios were compared to independent data on the Mg2+/Ca2+ ratios from skeletal carbonates (echinoderms and corals) and mid-ocean ridge flank calcite veins. Constant [Ca2+] of 11 mmolal is unlikely because this relatively low concentration generated unreasonably low seawater [SO2- 4] during most of the past 550 Myr and high Mg2+/Ca2+ ratios compared to independent data. Constant [SO2- 4] of 29 mmolal produced unreasonably high seawater [Ca2+] and lower Mg2+/Ca2+ ratios than those derived from fluid inclusions, echinoderms, corals, and calcite veins. Variable [Ca2+] and [SO2- 4] showed the best agreement with the Mg2+/Ca2+ ratios derived from fluid inclusions, echinoderms, corals, and calcite veins. © 2022 Elsevier B.V.
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    Combined LA-ICP-MS and cryo-SEM-EDS: an improved technique for quantitative analysis of major, minor, and trace elements in fluid inclusions in halite
    (Elsevier B. V., 2020-09-30) Weldeghebriel, MF; Lowenstein, TK; García-Veigas, J; Collins, D; Sendula, E; Bodnar, RJ; Graney, JR; Cendón, DI; Lensky, NG; Mor, Z; Sirota, I
    Quantitative multi-element analyses of single fluid inclusions in halite and other sedimentary minerals can provide information on the origin and chemical evolution of ancient surface waters on Earth. Integrated laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and cryogenic-scanning electron microscopy-energy dispersive spectroscopy (cryo-SEM-EDS) were used here for the quantitative analysis of fluid inclusions in halite. Single phase fluid inclusions in modern and ancient halite were analyzed using a 193 nm ArF excimer laser ablation system coupled with a quadrupole mass spectrometer to test a new calibration technique using magnesium (Mg) as an internal standard. Mg concentrations obtained by cryo-SEM-EDS analyses of fluid inclusions were used to convert LA-ICP-MS concentration ratios into absolute elemental concentrations. Mg concentrations of ancient fluid inclusions from cryo-SEM-EDS analyses were reproducible to better than 5% relative standard deviation (RSD). Comparison between the chemical composition of modern Dead Sea brine measured using ICP-OES (optical emission spectroscopy) and the composition of fluid inclusions in Dead Sea halite formed from those brines, shows that fluid inclusions in halite faithfully record the chemistry of the brines from which they precipitated. Overall LA-ICP-MS analytical precision for major ions K, Ca, S in SO4 (above 50 mmol/kg H2O) is better than 10% RSD and accuracies range from 2% to 21%. Mean concentrations of Li, B, Sr, Rb and Ba agree within 7% of their expected values and are reproducible within 15%, whereas Cs concentrations above detection limit are typically reproducible to within 15 to 25% RSD. For trace elements in seawater, such as U and Mo, quantitative analyses in fluid inclusions are achieved at concentrations above 20 nmol/kg H2O. The results from this study confirm that the precision and accuracy of major and minor elemental analysis is improved with Mg as an internal standard instead of Na and Cl used in previous studies. Controlled, optimized ablation of >30 μm fluid inclusions in halite improved the accuracy and precision and reduced the overall limit of detection (LOD) by one order of magnitude compared to previous studies. Wide ranges of LODs, between 0.7 nmol/kg H2O and 10 mmol/kg H2O, reflect variations in inclusion volume and elemental concentrations. Analytical accuracies obtained for major elements demonstrate that cryo-SEM-EDS and LA-ICP-MS are complementary microbeam techniques for chemical analysis of individual fluid inclusions in halite. © 2021 Elsevier B.V.
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    The elemental sulfur ore deposit of Salmerón: Las Minas de Hellín basin (Late Miocene, SE Spain)
    (Instituto Geologico y Minero de Espana, 2022-06) García-Veigas, J; Gimeno, D; Pineda, V; Cendón, DI; Sánchez-Román, M; Artiaga, D; Bembibre, G
    Strata-bound elemental sulfur deposits occur in different circum-Mediterranean Miocene sedimentary successions containing evaporites and high amounts of organic matter. It is widely known that bacterial sulfate reduction processes are the triggering mechanisms involved in the origin of hydrogen sulfide and the subsequent native sulfur. However, in most of these sedimentary successions, there is controversy over whether elemental sulfur formed in the basin floor, as the same time as the sediments (biosyngenetic), or later, during diagenesis (bioepigenetic). Las Minas de Hellín basin, in the SE Spain, contains one of the largest elemental sulfur deposits in Europe. Based on data recovered from mining company (1903 -1960) and a borehole campaign performed by MINERSA between 1987 and 1988, two native sulfur ore bodies are recognized. The upper sulfur body is hosted by carbonates and diatom-rich levels, whereas the lower sulfur body, only exploited in underground mines now closed, is hosted by gypsum. This work shows a petrological and geochemical study of core samples from the upper sulfur body in the Salmerón area (Murcia), 500 m west of the widely exploited area of Las Minas de Hellín (Albacete). In Salmerón, elemental sulfur occurs as pseudomorphs after primary sedimentary gypsum as well as filling fractures and bed joints. The elemental sulfur replacement is also related to calcification and silicification of the sedimentary biomediated dolomite. The mineralization is considered bioepigenetic formed during early diagenesis. Contribution from hydrothermal waters circulating through adjacent faults are not ruled out. ©2022 CSIC. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License
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    Exploring the hydrochemical evolution of brines leading to sylvite precipitation in ancient evaporite basins.
    (Copernicus Publications, 2010-05-02) Cendón, DI; Pueyo, JJ; Ayora, C; García-Veigas, J; Blanc-Valleron, MM
    Sylvite is a very common mineral in ancient evaporite deposits. Due to the absence of current deposits, the natural geochemical mechanism/s for synsedimentary sylvite precipitation and accumulation are not well understood. Numerous sylvite deposits or portions of them have been described as a result of diagenesis (i.e. Sergipe subbasin, Brasil). However, a number of deposits have been described as synsdimentary or being formed during primary evaporite deposition. It is the last group of deposits that can be studied to better understand the hydrochemical processes taking place in the brine at the onset of sylvite precipitation. The Salt IV sylvite beds from the Mulhouse potash basin, Alsace (France) have been described as synsedimentary in origin (LOWENSTEIN and SPENCER, 1990; CENDON et al., 2008). While sylvite in itself does not contain fluid inclusions viable for micro analysis, primary textures in neighboring halite are used as a proxy to understand brine evolution. Two halite-sylvite cycles from the B1 and B2 layers of the potash lower seam were selected. These exhibited clear primary halite crystal textures with sylvite adapting to an irregular halite sedimentary surface and finishing with a flat surface. The nine halite samples, selected at centimeter scale, provided close to 100 single fluid inclusion analyses, representing both the transition towards sylvite precipitation and the post sylvite precipitation. The fluid inclusion analyses revealed strong fluctuations in K concentration, well over the analytical error (<10%). These variations, in the same halite crystal, seem aligned in growth bands, with fluid inclusions within a certain growth band showing practically identical K concentrations, while neighboring bands exhibit a different concentration. Overall, the closer we are from a sylvite layer the higher K concentrations are. However, strong fluctuations continue when growth bands are compared. This pattern shows cycles of increasing K concentration along parallel growth bands with sharp falls followed by the initiation of a new increasing trend. The small “growth band” scale of the K concentration variations, suggests very sensitive processes within the brine with potential environmental changes (i.e. seasonal variations, day-night temperature fluctuations cycles) leading towards the final mass precipitation of a sylvite layer. © Author(s) 2010
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    Geochemical indicators in Western Mediterranean Messinian evaporites: implications for the salinity crisis
    (Elsevier B. V., 2018-09-01) García-Veigas, J; Cendón, DI; Gilbert, L; Lowenstein, TK; Artiaga, D
    The Messinian Salinity Crisis (MSC) led to deposition of one of the youngest saline giant on Earth. The increasing restriction of the connections between the Mediterranean, the Atlantic Ocean and the freshwater Paratethyan basins resulted in the deposition of massive amounts of evaporites (gypsum, anhydrite, halite and potash salts) in shallow marginal basins as well as in deep Mediterranean basins. Here we show that each gypsum unit in the circum-Mediterranean marginal basins in Sicily and Spain is characterized by a narrow range of sulfate isotopic values (δ34S ~ 23‰ and δ18O ~ 14‰ in the Lower Gypsum; δ34S ~ 23‰ and δ18O ~ 17‰ in the Upper Gypsum). Sulfate isotope compositions found in MSC evaporites from a variety of circum-Mediterranean basins are homogenously high relative to expected Late Miocene marine evaporites (δ34S ~ 22‰ and δ18O ~ 12‰). This points to a stratified Mediterranean Sea with a high-salinity, dense, and anoxic bottom water mass. An intermediate depth gypsum-saturated brine flooded marginal basins from which selenite deposits formed during the MSC Stage 1 (Primary Lower Gypsum) and MSC Stage 3 (Upper Gypsum). Messinian brines were gradually affected by biogenic redox processes and isotopically differentiated from global seawater values. The homogeneity of isotopic signatures between distant synchronous gypsum deposits further supports the deep-basin deep-water model for the Mediterranean during the entire MSC event. © 2018 Elsevier B.V.
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    Large celestine orebodies formed by early-diagenetic replacement of gypsified stromatolites (Upper Miocene, Montevive–Escúzar deposit, Granada Basin, Spain)
    (Elsevier, 2015-01-01) García-Veigas, J; Rosell, L; Cendón, DI; Gilbert, L; Martín, JM; Torres-Ruiz, J; Ortí, F
    The Montevive and the Escúzar stratabound celestine orebodies in the Upper Miocene evaporite succession of the intramontane Granada Basin (Spain) constitute one of the largest strontium deposits in the world. Celestine occurs within a gypsum/anhydrite–halite evaporite sequence where it replaces gypsum and gypsified stromatolites preserving carbonate peloids. 87Sr/86Sr and δ34S values in the Montevive celestine deposit are close to those reported for the saline unit (Chimeneas Halite; marine to nonmarine) but higher than those of the overlying gypsum unit (Agrón Gypsum; nonmarine). 87Sr/86Sr and δ34S isotope values in the Escúzar celestine deposit match the nonmarine values recorded in the upper part of the Agrón Gypsum. The similarity in isotope values between celestine and the corresponding gypsum host in the Escúzar deposit points to early-diagenetic mineralization. According to that, both orebodies are diachronous. Gypsum pseudomorphs and molds, intraformational breccias and karst structures in these celestine deposits point to dissolved gypsum as the main sulfate source. Diagenetic–hydrothermal CaCl2 brines are interpreted to be the main strontium source. The spatial relationship between gypsified stromatolites and the ore deposits suggests the existence of coeval thermal springs related to fractures, bordering the saline lake. The proposed model envisages gypsum dissolution by SO42 −-poor and Sr2 +-rich, CaCl2 diagenetic–hydrothermal water discharging in coastal ponds at times of dry periods and low meteoric water inflow. The increase in SO42 − concentration by gypsum dissolution and the low solubility of SrSO4 would lead to celestine precipitation replacing gypsum and gypsified stromatolites. © 2014 Elsevier B.V.
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    Late Miocene evaporite geochemistry of lorca and fortuna basins (Eastern Betics, SE Spain): evidence of restriction and continentalization
    (Wiley, 2020-09-26) García-Veigas, J; Gibert, L; Cendón, DI; Artiaga, D; Corbí, H; Soria, JM; Lowenstein, TK; Sanz, E
    The Lorca and Fortuna basins are two intramontane Neogene basins located in the eastern Betic Cordillera (SE Spain). During the Late Tortonian—Early Messinian, marine and continental evaporites precipitated in these basins as a consequence of increased marine restriction and isolation. Here we show a stratigraphic correlation between the evaporite records of these basins based on geochemical indicators. We use SO4 isotope compositions and Sr isotopic ratios in gypsum, and halite Br contents to characterize these units and to identify the marine or continental source of the waters feeding the evaporite basins. In addition, we review the available chronological information used to date these evaporites in Lorca (La Serrata Fm), including a thick saline deposit, that we correlate with the First Evaporitic Group in Fortuna (Los Baños Fm). This correlation is also supported by micropalaeontological data, giving a Late Tortonian age for this sequence. The Second Evaporitic Group, (Chicamo Fm), and the Third Evaporitic Group (Rambla Salada Fm) developed only in Fortuna during the Messinian. According to the palaeogeographical scheme presented here, the evaporites of the Lorca and Fortuna basins were formed during the Late Tortonian—Early Messinian, close to the Betic Seaway closure. Sulphate isotope compositions and Sr isotopic ratios of the Ribera Gypsum Mb, at the base of the Rambla Salada Fm (Fortuna basin), match those of the Late Messinian selenite gypsum beds in San Miguel de Salinas, in the near Bajo Segura basin (40 km to the East), and other Messinian Salinity Crisis gypsum deposits in the Mediterranean. According to these geochemical indicators and the uncertainty of the chronology of this unit, the assignment of the Rambla Salada Fm to the MSC cannot be ruled out. © 1999-2024 John Wiley & Sons, Inc or related companies.
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    Late Miocene evaporite geochemistry of Lorca and Fortuna basins (Eastern Betics, SE Spain): Evidence of restriction and continentalization
    (John Wiley & Sons, Inc., 2019-09-26) García-Veigas, J; Gilbert, L; Cendón, DI; Artiaga, D; Corbí, H; Soria, JM; Lowenstein, TK; Sanz, E
    The Lorca and Fortuna basins are two intramontane Neogene basins located in the eastern Betic Cordillera (SE Spain). During the Late Tortonian—Early Messinian, marine and continental evaporites precipitated in these basins as a consequence of increased marine restriction and isolation. Here we show a stratigraphic correlation between the evaporite records of these basins based on geochemical indicators. We use SO4 isotope compositions and Sr isotopic ratios in gypsum, and halite Br contents to characterize these units and to identify the marine or continental source of the waters feeding the evaporite basins. In addition, we review the available chronological information used to date these evaporites in Lorca (La Serrata Fm), including a thick saline deposit, that we correlate with the First Evaporitic Group in Fortuna (Los Baños Fm). This correlation is also supported by micropalaeontological data, giving a Late Tortonian age for this sequence. The Second Evaporitic Group, (Chicamo Fm), and the Third Evaporitic Group (Rambla Salada Fm) developed only in Fortuna during the Messinian. According to the palaeogeographical scheme presented here, the evaporites of the Lorca and Fortuna basins were formed during the Late Tortonian—Early Messinian, close to the Betic Seaway closure. Sulphate isotope compositions and Sr isotopic ratios of the Ribera Gypsum Mb, at the base of the Rambla Salada Fm (Fortuna basin), match those of the Late Messinian selenite gypsum beds in San Miguel de Salinas, in the near Bajo Segura basin (40 km to the East), and other Messinian Salinity Crisis gypsum deposits in the Mediterranean. According to these geochemical indicators and the uncertainty of the chronology of this unit, the assignment of the Rambla Salada Fm to the MSC cannot be ruled out. © 2019 The Authors. Basin Research © 2019 John Wiley & Sons Ltd, European Association of Geoscientists & Engineers and International Association of Sedimentologists
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    Marine to lacustrine evolution in an evaporitic environment: the late miocene Lorca Basin, Spain
    (U.S. Department of the Interior and U.S. Geological Survey, 2015-06-15) García-Veigas, J; Cendón, DI; Gilbert, L; Rosell, L; Ortí, F; Playà, E; Prats, E; Soria, JM; Corbí, H; Sanz, E
    The Lorca Basin, in the eastern sector of the Betic Range (SE Spain), is an intramontane basin recording an evaporitic succession (La Serrata Formation), of up to 300 m thick, with a ~ 235 m thick saline unit within. Altogether, the evaporitic record was originally interpreted as Messinian (Geel, 1976) and later assigned to Tortonian (Krijgsman and others, 2000). The detailed geochemical study provides relevant paleogeographic information at local scale and highlights the importance of hydrochemical changes taking place in coastal evaporite basins changing between marine and non-marine conditions without lithological variations. A stratigraphic framework is proposed correlating the outcropping gypsum beds (Gypsum Mb of La Serrata Fm) and the subsurface saline succession (Halite Mb) by means of strontium and sulfate isotopes (fig. 1). In the lower part of the Gypsum Mb the isotopic trends suggest that gypsum formed from marine waters while in the upper part, with Triassic isotopic signals, gypsum formed in a coastal lake mainly fed by non-marine waters. In the Halite Mb, the textures indicate precipitation in a very shallow, often dried, environment. Fluid inclusion compositions and bromine contents in salt show an evolution from normal marine brines, to brines resulting from the recycling of previously precipitated halite essentially by means of non-marine waters in a coastal lake setting. The overlying Laminated Pelite Mb (Geel, 1976) consists in its lower part of a number of non-marine gypsum beds intercalated between marine marls suggesting post-evaporitic refilling events of the Lorca Basin by the Mediterranean Sea before its final continentalization during the Pliocene. Biostratigraphic studies in progress are expected to refine age allocation within the evaporitic unit and therefore improve our understanding of the relationship to the “Messinian Salinity Crisis”. © 2015 The Authors
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    The Messinian evaporites of the Mesaoria basin (North Cyprus): a discrepancy with the current chronostratigraphic understanding
    (Elsevier B. V., 2021-10-04) Artiaga, D; García-Veigas, J; Cendón, DI; Atalar, C; Gilbert, L
    Large volume of evaporites were deposited during the Messinian Salinity Crisis (MSC) across the Mediterranean. These evaporites are currently outcropping on land and are interpreted by seismic profiles beneath the Mediterranean floor. Biostratigraphic, magnetostratigraphic and astrochronologic data recovered from sediments below and above outcropping evaporites, together with gypsum facies associations and stratigraphic cyclicity, are the cornerstone of what is known as the MSC ‘three-stage’ model: Primary Lower Gypsum (PLG) – MSC stage 1, Resedimented Lower Gypsum (RLG) - MSC stage 2, and Upper Gypsum (UG) – MSC stage 3. Although this litho- and chronostratigraphic model is mainly based on the gypsum succession in Sicily, it is being currently applied by many investigators across the Mediterranean. The Mesaoria basin, in North Cyprus, hosts well exposed MSC gypsum deposits of the Kalavasos Fm. Two informal units are distinguished in the gypsum succession. The lower unit, largely consisting of clastic gypsum deposits, is conformably overlaid by the upper unit, mostly consisting of ‘in situ’ vertically-oriented selenite deposits. Based on the lithostratigraphic gypsum succession, the lower unit could be tentatively assigned to RLG - MSC stage 2, while the upper unit could correspond to UG - MSC stage 3. However, our lithologic and geochemical (δ34Ssulfate δ18Osulfate, 87Sr/86Sr) data in gypsum points that the upper unit fits with those of the PLG – MSC stage 1. For the first time, thick vertically-oriented selenite beds with lithofacies and geochemical signatures diagnostic of PLG deposits lay conformably over clastic gypsum successions diagnostic of RLG deposits in the currently accepted ‘three-stage’ model. In North Cyprus, ‘in situ’ selenite platforms and ‘clastic’ gravity-flow gypsum deposits are coeval involving erosion and redeposition during the same evolutive stage. The complete gypsum succession in North Cyprus must be considered as MSC Lower Evaporites in the ‘two-step’ model (Lower Evaporites and Upper Evaporites) classically proposed prior to the ‘three-stage’ model. We show how nearby Messinian evaporite basins in the same island (North and South Cyprus) can produce different sedimentary records. Our data cast doubts on the systematic application of the ‘three-stage’ litho- and chronostratigraphic model to North Cyprus and other MSC Mediterranean evaporite successions. This work highlights the importance of local processes in the sedimentation and distribution of MSC evaporites in active tectonic settings, and alerts against extrabasinal MSC correlations based on gypsum facies distribution. © The Authors CC BY 4.0
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    Rapid changes in major ion chemistry of seawater and the end-permian mass extinction
    (Geological Society of America, 2017-10-22) Lowenstein, TK; García-Veigas, J; Cendón, DI; Gilbert Beotas, L
    The end-Permian mass extinction is interpreted to have involved elevated global temperatures, ocean anoxia, ocean acidification, a disturbed sulfur cycle, and ocean euxinia. The same period also contains one of the largest accumulations of evaporites in the geologic record, including saline giants in the US, England, the Netherlands, Germany, Poland, Ukraine, and Russia. Here we show from fluid inclusions in marine halites that there was a major shift in seawater chemistry involving SO4and Ca which coincides with other global perturbations in seawater chemistry at the end-Permian and perhaps the mass extinction. Permian seawater, determined from the chemical compositions of fluid inclusions in marine halites from the North American Permian Basin (Kansas, Texas and New Mexico) and the Southern Permian Basin (Central Europe) shares chemical characteristics with modern seawater, including SO4 > Ca at the point of gypsum precipitation and evolution into a Mg-Na-K-SO4-Cl brine. An abrupt shift to Ca-rich fluid inclusions occurs in the Changhsingian Rustler Formation of New Mexico over 1.5 meter of stratigraphic section and in the Changhsingian Zechstein Cycle Na2 and basal Na3 Cycle of Poland. Such an abrupt shift in the major ion chemistry of seawater in two basins at about the same time is unusual because the residence times of SO4 and Ca in seawater are 10 m.y. and 1 m.y., respectively. Changes in the major ion chemistry of seawater are well known to occur over periods of 106 to 107 years, so the end-Permian seawater chemistry shift indicates some catastrophic process. The shift from sulfate-rich to calcium-rich brines coincides with a marked drop in δ34S in Zechstein and Rustler anhydrite, which suggests a link between changes in the major ion chemistry of seawater and perturbations in the sulfur cycle. These changes are interpreted to have been caused by overturn of anoxic sulfidic deep-waters from the Panthalassan superocean during the Changhsingian stage which may have coincided with the end-Permian mass extinction.
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    Salt deposition and brine evolution in the Granada Basin (Late Tortonian, SE Spain)
    (Elsevier Science BV, 2013-01-01) García-Veigas, J; Cendón, DI; Rosell, L; Orti, F; Torres Ruiz, J; Martín, JM; Sanz, E
    A group of sedimentary basins in the Betic Chain were formed during the Middle-Late Miocene as a result of the closure of the Tethys during the Alpine orogeny. In the Late Miocene (Tortonian-Messinian) the connections between the Atlantic Ocean and Mediterranean Sea were interrupted and those basins hosted major evaporites. The Granada Basin, an 'inner basin' located far from the Mediterranean, contains a thick rock salt deposited during the latest Tortonian in the transition from marine to non-marine conditions. In the centre of the basin, three halite-bearing units overlie a basal anhydrite bed: the Lower Halite Unit, the Intermediate Sandstone Unit and the Upper Halite Unit. Fluid inclusion compositions and bromine concentrations in halite, together with stable isotopes (delta S-34(sulfate), delta O-18(sulfate) and Sr-87/Sr-86) indicate a mixture of different inflow waters in the Granada Basin, beginning with a marine lagoon that evolved into a salt-pan strongly isolated from the sea. Saline waters evolved from sulfate-rich marine-derived to sulfate-depleted non-marine brines influenced by the addition of CaCl2-rich inputs. These CaCl2-rich waters were probably linked to thermal fluids associated with a major crustal fracture system (Crevillente or Cadiz-Alicante fault system) that cuts through the Granada Basin. © 2013, Elsevier Ltd.
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    Seafloor hydrothermal systems control seawater chemistry: evidence from fluid inclusion in halite
    (The Geological Society of America, 2019-09-24) Weldeghebriel, MF; Lowenstein, TK; Demicco, RV; Graney, JR; García-Veigas, J; Cendón, DI; Bodnar, RJ; Sendula, E
    Long-term changes in the major ion and isotopic composition of seawater coincide with icehouse-greenhouse climate fluctuations, calcite-aragonite seas, and sea level changes. However, there is disagreement over what processes controlled the changes in ocean chemistry. This study uses a new record of Li concentration in paleoseawater to explore how temporal variations in the flux of MOR hydrothermal brines, the largest source of Li to seawater, and reverse weathering of seafloor basalts (important sink) control the oceanic Li cycle on multimillion-year time scales. Here we present a 350-million-year record of seawater lithium concentrations [Li+]sw from direct measurement of primary fluid inclusions in marine halite using combined LA-ICP-MS and cryo SEM-EDS. We also present a 150 Myr forward model of [Li+]sw. From 350-0 Ma, the lithium concentration of seawater oscillated systematically, parallel to secular variations of sea level, greenhouse-icehouse climates, and major ion chemistry such as the Mg2+/Ca2+ ratio. Highest seawater Li occurred during the Cretaceous, up to one order of magnitude higher than modern [Li+]sw, which coincides with low seawater Mg2+/Ca2+ ratios, high atmospheric CO2, and Mesozoic-Early Cenozoic Greenhouse climates. Such high Li concentrations require high MOR hydrothermal activity. Conversely, Permian and Cenozoic (35-0 Ma) seawater had relatively low Li, consistent with high Mg2+/Ca2+ ratios, low atmospheric CO2, and late Paleozoic and Cenozoic icehouse periods. The forward model involves 10 Kyr time steps and variable cycling of hydrothermal fluids through the axial portion of the MOR system and variable rates of low-temperature weathering of seafloor basalts. The model agrees well with paleoseawater fluid inclusion data for Li. The same model parameters, with variable Li isotope fractionation of off-axis oceanic crust, are used to successfully model the 9‰ increase of δ7Li in seawater from 60-0 Ma. Our data and modeling suggest that seafloor hydrothermal systems exerted the dominant control on the [Li+] and δ7Li composition of Phanerozoic seawater. These data will be further used to test the long-term relationships between seafloor MOR activity, the carbon cycle, and climate. © Copyright 2019 The Geological Society of America (GSA)
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    Sulfate isotope composition of Messinian evaporites in the Piedmont basin (Italy)
    (Sociedad Geologica de Espana, 2021-12-13) García-Veigas, J; Gibert, L; Cendón, DI; Dela Pierre, F; Natalicchio, M; Artiaga, D
    The Piedmont basin (NW Italy) records a Messinian Salinity Crisis (MSC) succession including a selenite gypsum deposit assigned to the Primary Lower Gypsum (PLG, MSC stage 1). Strontium isotope ratios are in the range of the PLG deposits of the Mediterranean area. Sulfate isotope compositions of vertically oriented selenite gypsum beds, in the lower part of the succession, are similar to those reported in other PLG deposits. However, flattened branching selenite cones in the upper part show higher isotope compositions, mainly in δ34S values, suggesting intense BSR conditions, stronger than reported in other PLG deposits. We interpret this chemical shift during deposition of the upper part of the PLG as the result of increased marine restriction assisted by the marginal position of this basin in the Adriatic Gulf during the Apennine and Alpine uplifts. This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
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    Sulfate isotope compositions (δ34S, δ18O) and strontium isotopic ratios (87Sr/86Sr) of Triassic evaporites in the Betic Cordillera (SE Spain)
    (SGE, 2014-01-01) Ortí, F; Pérez-López, A; García-Veigas, J; Rosell, L; Cendón, DI; Pérez-Valera, F
    Sulfate isotope compositions (δ34S and δ18O) and strontium isotope ratios (87Sr/86Sr) of Triassic evaporites in the Betic Cordillera are addressed for the first time in the present work. Isotope values have been determined in gypsum and anhydrite samples of the Germanic-type facies (Buntsandstein, Muschelkalk and Keuper) coming from different outcrops spanning the complete Triassic Period and corresponding to both the Internal Zones and the External (Prebetic, Subbetic) Zones of this chain. More precise age assignments and stratigraphic controls are often obscured because of the intense halokinetic and tectonic deformation occurred during the Alpine Orogeny in the Betic Cordillera. Isotope values of Triassic sulfates obtained in the present study range between 12.5 and 16.6 ‰ for δ34S, between 8.9 and 16.9 ‰ for δ18O, and between 0.707615 and 0.708114 for 87Sr/86Sr. These values, as a whole, are in agreement with those of worldwide Triassic marine evaporites.
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    Zechstein saline brines in Poland, evidence of overturned anoxic ocean during the late Permian mass extinction event
    (Elsevier, 2011-11-24) García-Veigas, J; Cendón, DI; Pueyo, JJ; Peryt, T
    Bromine concentrations in halite, sulfate isotopes (delta S-34 and delta O-18), and major ion concentrations in primary fluid inclusions from three boreholes in the Late Permian Zechstein evaporites have revealed sharp variations in marine derived brines within the Polish sector of the European Southern Permian Basin. The base of the Older Halite (Na2), during the latest Permian, registers a change from sulfate-rich brines, similar in composition to modern evaporated seawater, to sulfate-depleted brines (calcium-rich). This change coincides with a drop in delta S-34 to values close to +9 parts per thousand, not observed in delta O-18 counterparts. Opposite isotope (delta S-34-delta O-18) trends through the Na2 unit cannot be explained by changes in restriction conditions. We propose that the change to sulfate-depleted (calcium-rich) brines during halite deposition of the PZ2 (Stassfurt) cycle is related to the overturn of anoxic sulfidic deep-waters from the Panthalassa stratified superocean coinciding in time with the Permian-Triassic mass extinction event. The reconstruction of chemical changes in brines reveals two major evaporite sequences of increasing concentration that do not match the classic lithostratigraphic cycles. The first evaporite sequence (PZES-1) contain the evaporite units of the PZ1 (Werra) cycle, the PZ2 (Stassfurt) cycle, the Main Anhydrite (A3), and the base of the Younger Halite (Na3) of the PZ3 (Leine) cycle. The second evaporite sequence (PZES-2) is represented by almost the entire Na3 unit and the PZ4 (Aller) cycle. (C) 2011 Elsevier B.V.