Sr isotope fractionation in a karst river: case study of Krka, Croatia

Precipitation of calcite from water fractionates strontium (Sr) isotopes because of preferential incorporation of light (86Sr) isotopes into the solid phase, making continental carbonates one of the most 88Sr depleted reservoirs. It was suggested that carbonate precipitation is the most likely process controlling &#948;88/86Sr composition of karst water. Therefore, the 88Sr enrichment of river water could be used for the estimation of Sr and carbonate precipitation at catchment scale.In the present study, we report on trace element partitioning and Sr isotope fractionation between tufa and water in the groundwater fed karst river Krka (Croatia). Water and tufa along with samples of bedrock and soil as the main contributors of dissolved and particulate Sr at seven main waterfalls and cascades along a 33 km section of the river were analysed for trace element and Sr isotope composition (&#948;88/86Sr).The highest &#948;88/86Sr values were measured in soils and in siliciclastic rocks, while in limestone, the &#948;88/86Sr values were similar to those of old tufa precipitated in the period between 96 and 141 ky BP. Recent tufa, however, was considerably depleted in 88Sr. The isotope fractionation between water and recent tufa varied a lot and was inversely correlated with Mg and Sr partitioning coefficients, while correlations with precipitation rates and temperature were rather weak. The &#948;88/86Sr of recent tufa was strongly correlated with the stable isotope composition of organic carbon, which indicates that apart from hydrochemical, hydraulic parameters and temperature, plants and microbial communities that knowingly stimulate the tufa formation also affect the isotope fractionation of Sr.

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δ60Ni and δ13C Composition of Serpentinites and Carbonates of the Tekirova Ophiolite, Turkey, and Meatiq Ophiolite, Egypt

Frontiers in Earth Science ◽

10.3389/feart.2021.651967 ◽

2021 ◽

Vol 9 ◽

Author(s):

Anna Neubeck ◽

Arjen Boosman ◽

Hakan Hosgörmez ◽

Dogacan Özcan ◽

Arman Boskabadi ◽

...

Keyword(s):

Isotope Fractionation ◽

Solid Phase ◽

Eastern Desert ◽

Carbonate Precipitation ◽

Active System ◽

Isotopic Signatures ◽

Sw Turkey ◽

Weathered Rocks ◽

Phase Data ◽

Reported Data

Nickel isotope fractionation patterns in continental ultramafic environments generally show a depletion of δ60Ni in weathered rocks and an enrichment in bedrock samples. The present study focuses on stable Ni isotope fractionation patterns in carbonate-rich, ultramafic ophiolite samples with concomitant fluids at an active serpentinization site in southwestern Turkey, with a comparison to results from an inactive serpentinization site in the Eastern Desert of Egypt with carbonate-rich samples. All solid phase data from the inactive serpentinization area are consistent with previously reported values from serpentinites, whereas the solid precipitates in the active area (SW Turkey) give values slightly heavier than previously reported data. However, the Ni isotopic signatures in the active serpentinization system likely reflect the scavenging of light Ni by iron oxide and carbonate precipitation, as has been previously demonstrated in laboratory coprecipitation experiments. It is also possible that the active system results resemble previous laboratory experimental results that show a relatively strong initial fractionation between fluids and solids, which then diminishes with time due to aging of the precipitates.

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Trace-element partitioning and boron isotope fractionation between white mica and tourmaline

The Canadian Mineralogist ◽

10.3749/canmin.49.1.165 ◽

2011 ◽

Vol 49 (1) ◽

pp. 165-176 ◽

Cited By ~ 35

Author(s):

S. Klemme ◽

H. R. Marschall ◽

D. E. Jacob ◽

S. Prowatke ◽

T. Ludwig

Keyword(s):

Trace Element ◽

Isotope Fractionation ◽

White Mica ◽

Boron Isotope ◽

Trace Element Partitioning ◽

Element Partitioning

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Tracer versus trace element diffusion: Diffusional decoupling of Sr concentration from Sr isotope composition

Geochimica et Cosmochimica Acta ◽

10.1016/0016-7037(89)90177-4 ◽

1989 ◽

Vol 53 (11) ◽

pp. 3015-3023 ◽

Cited By ~ 81

Author(s):

Don R Baker

Keyword(s):

Trace Element ◽

Isotope Composition ◽

Sr Isotope ◽

Element Diffusion

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MN INCORPORATION INTO CALCITE: INFLUENCE OF INTERFACIAL DYNAMICS ON TRACE ELEMENT PARTITIONING, CALCIUM ISOTOPE FRACTIONATION, AND GROWTH KINETICS

10.1130/abs/2019am-340342 ◽

2019 ◽

Author(s):

Jennifer V. Mills ◽

◽

Holly A. Barnhart ◽

Donald J. DePaolo ◽

Laura N. Lammers

Keyword(s):

Trace Element ◽

Growth Kinetics ◽

Isotope Fractionation ◽

Calcium Isotope ◽

Interfacial Dynamics ◽

Trace Element Partitioning ◽

Element Partitioning

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Trace element partitioning in mixed-habit diamonds

Chemical Geology ◽

10.1016/j.chemgeo.2013.07.013 ◽

2013 ◽

Vol 355 ◽

pp. 134-143 ◽

Cited By ~ 15

Author(s):

D. Howell ◽

W.L. Griffin ◽

N.J. Pearson ◽

W. Powell ◽

P. Wieland ◽

...

Keyword(s):

Trace Element ◽

Trace Element Partitioning ◽

Element Partitioning

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Nd, Pb, and Sr isotope composition of juvenile magmatism in the Mesozoic large magmatic province of northern Chile (18–27°S): indications for a uniform subarc mantle

Contributions to Mineralogy and Petrology ◽

10.1007/s00410-006-0119-y ◽

2006 ◽

Vol 152 (5) ◽

pp. 571-589 ◽

Cited By ~ 35

Author(s):

Friedrich Lucassen ◽

Wolfgang Kramer ◽

Viola Bartsch ◽

Hans-Gerhard Wilke ◽

Gerhard Franz ◽

...

Keyword(s):

Isotope Composition ◽

Northern Chile ◽

Sr Isotope

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Trace element partitioning between garnet and chondritic melt from 5 to 9 GPa: implications for the onset of the majorite transition in the martian mantle

Physics of The Earth and Planetary Interiors ◽

10.1016/s0031-9201(03)00150-x ◽

2003 ◽

Vol 139 (1-2) ◽

pp. 149-169 ◽

Cited By ~ 50

Author(s):

David S Draper ◽

Dimitris Xirouchakis ◽

Carl B Agee

Keyword(s):

Trace Element ◽

Trace Element Partitioning ◽

Element Partitioning

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Dissolution and recrystallization in modern shelf carbonates: evidence from pore water and solid phase chemistry

Philosophical Transactions of the Royal Society of London Series A Physical and Engineering Sciences ◽

10.1098/rsta.1993.0072 ◽

1993 ◽

Vol 344 (1670) ◽

pp. 27-36 ◽

Cited By ~ 75

Keyword(s):

Organic Matter ◽

Pore Water ◽

Solid Phase ◽

Chemical Exchange ◽

Isotope Composition ◽

Geochemical Data ◽

Carbonate Sediments ◽

Pore Waters ◽

Carbonate Minerals ◽

Carbonate Production

We present an overview of geochemical data from pore waters and solid phases that clarify earliest diagenetic processes affecting modern, shallow marine carbonate sediments. Acids produced by organic matter decomposition react rapidly with metastable carbonate minerals in pore waters to produce extensive syndepositional dissolution and recrystallization. Stoichiometric relations among pore water solutes suggest that dissolution is related to oxidation of H 2 S which can accumulate in these low-Fe sediments. Sulphide oxidation likely occurs by enhanced diffusion of O 2 mediated by sulphide-oxidizing bacteria which colonize oxic/anoxic interfaces invaginating these intensely bioturbated sediments. Buffering of pore water stable isotopic compositions towards values of bulk sediment and rapid 45 Ca exchange rates during sediment incubations demonstrate that carbonate recrystallization is a significant process. Comparison of average biogenic carbonate production rates with estimated rates of dissolution and recrystallization suggests that over half the gross production is dissolved and/or recrystallized. Thus isotopic and elemental composition of carbonate minerals can experience significant alteration during earliest burial driven by chemical exchange among carbonate minerals and decomposing organic matter. Temporal shifts in palaeo-ocean carbon isotope composition inferred from bulk-rocks may be seriously compromised by facies-dependent differences in dissolution and recrystallization rates.

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