Seawater Sr isotope variations through time: A procedure for constructing a reference curve to date and correlate marine sedimentary rocks

Smalley, P. C.; Higgins, A. C.; Howarth, Richard J.; Nicholson, H. Alleyne; Jones, Charles E.; Swinburne, Nicola H.M.; Bessa, Julian

doi:10.1130/0091-7613(1994)022<0431:ssivtt>2.3.co;2

Cited by 66 publications

(24 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8). Values are slightly lower but well within the error bars of Burke et al (1982), Smalley et al (1994), andVeizer et al (1999). The LST and DST samples of the La Vid Group are slightly enriched in 87 Sr (up to 0.7093), which is normal for recrystallized marine carbonates, as some 87 Sr is liberated from the clay minerals of the surrounding and/or interbedded clay minerals and shales during burial (Machel and Cavell 1999).…”

Section: Sr Isotopessupporting

confidence: 51%

See 1 more Smart Citation

Covariance of C- and O-isotopes with magnetic susceptibility as a result of burial diagenesis of sandstones and carbonates: an example from the Lower Devonian La Vid Group, Cantabrian Zone, NW Spain

Schneider

Bechstädt

Machel

2004

Int J Earth Sci (Geol Rundsch)

View full text Add to dashboard Cite

The burial diagenesis of sandstones, limestones, and dolostones of the Lower Devonian La Vid Group in the Cantabrian Zone (NW Spain) reveal a covariance of carbon and oxygen isotope values with magnetic susceptibility. Also, strontium isotopes, and to a minor degree Fe, follow this trend. The main carriers of the magnetic susceptibility appear to be diagenetic Fe-carbonates, i.e., siderite, ferroan dolomite, and ankerite, which occur as cements in primary and secondary voids, as well as in fractures. In some layers, especially at the top of the succession there occurs additionally secondary Fe-chlorite and pyrite. The Fe-carbonates were formed during upward migration of a reducing, iron-bearing, petroliferous fluid that was depleted in 13 C and carried radiogenic Sr. Similar geochemical covariance and/or correlations can be expected in other sedimentary successions affected by the migration of petroliferous formation fluids.

show abstract

Section: Sr Isotopessupporting

confidence: 51%

“…The baseline for Lower DMC is about 0.7085-0.7088 (Burke et al 1982;Smalley et al 1994;Veizer et al 1999). Brachiopod values from the La Vid Group (Ala 1996) are shown as the reference for the other La Vid samples (Fig.…”

Section: Sr Isotopesmentioning

confidence: 94%

Covariance of C- and O-isotopes with magnetic susceptibility as a result of burial diagenesis of sandstones and carbonates: an example from the Lower Devonian La Vid Group, Cantabrian Zone, NW Spain

Schneider

Bechstädt

Machel

2004

Int J Earth Sci (Geol Rundsch)

View full text Add to dashboard Cite

show abstract

“…Because of limited brachiopod availability in the Mesozoic, belemnites were used instead as the best available carrier phases (Jones et al, 1994a;Jones et al, 1994b;Smalley et al, 1994;Veizer et al, 1999). Well preserved Phanerozoic fossil belemnite samples have Fe concentrations less than 150μg/g and Mn concentrations less than 20μg/g (Jones et al, 1994a;Jones et al, 1994b).…”

Section: Introductionmentioning

confidence: 99%

The Phanerozoic δ88/86Sr record of seawater: New constraints on past changes in oceanic carbonate fluxes

Vollstaedt

Eisenhauer

Wallmann

et al. 2014

Geochimica et Cosmochimica Acta

108

View full text Add to dashboard Cite

The isotopic composition of Phanerozoic marine sediments provides important information about changes in seawater chemistry. In particular, the radiogenic strontium isotope ( 87 Sr/ 86 Sr) system is a powerful tool for constraining plate tectonic processes and their influence on atmospheric CO 2 concentrations. However, the 87 Sr/ 86 Sr isotope ratio of seawater is not sensitive to temporal changes in the marine strontium (Sr) output flux, which is primarily controlled by the burial of calcium carbonate (CaCO 3 ) at the ocean floor. The Sr budget of the Phanerozoic ocean, including the associated changes in the amount of CaCO 3 burial, is therefore only poorly constrained. Here, we present the first stable isotope record of Sr for Phanerozoic skeletal carbonates, and by inference for Phanerozoic seawater (δ 88/86 Sr sw ), which we find to be sensitive to imbalances in the Sr input and output fluxes. This δ 88/86 Sr sw record varies from ~0.25‰ to ~0.60‰ (vs. SRM987) with a mean of ~0.37‰. The fractionation factor between modern seawater and skeletal The oceanic net carbonate flux of Sr (F(Sr) carb ) varied between an output of -4.7x10 10 mol/Myr and an input of +2.3x10 10 mol/Myr with a mean of -1.6x10 10 mol/Myr.On time scales in excess of 100Myrs the F(Sr) carb is proposed to have been controlled by the relative importance of calcium carbonate precipitates during the "aragonite" and "calcite" sea episodes. On time scales less than 20Myrs the F(Sr) carb seems to be controlled by variable combinations of carbonate burial rate, shelf carbonate weathering and recrystallization, ocean acidification, and ocean anoxia. In particular, the Permian/Triassic transition is marked by a prominent positive δ 88/86 Sr sw -peak that reflects a significantly enhanced burial flux of Sr and carbonate, likely driven by bacterial sulfate reduction (BSR) and the related alkalinity production in deeper anoxic waters. We also argue that the residence time of Sr in the Phanerozoic ocean ranged from ~1Myrs to ~20Myrs.

show abstract

“…Trend 1 shows significant variations of S180 values with practically no changes in 87Sr/86Sr, whereas trend 2 represents an end-member where both tracers vary significantly. Grey box indicates isotopic composition o f calcites in equilibrium with Visean seawater (Lohmann and Walker, 1989;Smalley et at., 1994). (C) Scatterplot o f [Sr] vs 87Sr/86Sr for samples of the micritic "m" and oolitic "o" units.…”

Section: S O T O P E G E O C H E M I S T R Y -R E S U L T Smentioning

confidence: 99%

“…Trend 1 shows no variation of 87Sr/86Sr for drastic changes in [Sr], whereas trend 2 shows significant variations for both tracers. Grey boxes indicate Sr concentrations and isotopic ratios for aragonite "A" and calcite "C" in equilibrium with Visean seawater (Veizer, 1983;Smalley et al, 1994).…”

Section: S O T O P E G E O C H E M I S T R Y -R E S U L T Smentioning

confidence: 99%

Burial diagenesis model for the Macumber Formation on Cape Breton Island - implications for the tectonic evolution of the Windsor Group

Savard

Lynch

Fallara

1996

atgeol

View full text Add to dashboard Cite

The Macumber Formation, a finely laminated limestone consisting of two thin units, represents a key strati graphic marker at the base o f the Visean Windsor Group. On Cape Breton Island the formation hosts numerous PbZn occurrences, and its upper boundary is in contact with rocks ranging in age from Visean (early Carboniferous) to Westphalian (middle Carboniferous), the origin o f the stratigraphic omissions being debatable.This first inorganic diagenesis study identifies nine post-depositional processes, including the stabilization of marine components, and evaporite and anhedral calcite precipitation. The (-13.0 to 2.0%o), 87Sr/86Sr (0.7076 to 0.7079) and [Sr] (50 to 10000 ppm) of samples, including upper and basal whole-rock units and anhedral calcite cements, show two trends enveloping the entire field of data. The trends suggest that an evaporite-derived, non-radiogenic fluid and a clastic-derived radiogenic fluid mixed and interacted with the limestone sediments, in a progressively deeper burial environment. The evaporite-derived fluid mostly imprinted the top unit o f the for mation. The field investigations, microscope observations and geochemical results do not indicate a meteoric overprint as would be expected if an unconformity existed along the top o f the formation. The burial history documented here, and the presence of fibrous calcite indicating bedding parallel shearing, support a detachment model to explain the stratigraphic omissions within the Windsor Group.La Formation de Macumber, composee de calcaires fins en deux minces unites, represente un marqueur stratigraphique crucial k la base du Groupe de Windsor. A Pile du Cap Breton, la formation encaisse plusieurs indices Pb-Zn et constitue la limite inferieure d'une serie d'omissions stratigraphiques k l'interieur du Groupe de Windsor, l'origine desquelles est fortement d6battue.Cette premiere investigation de la diagenese inorganique place neuf processus en une succession post-ddpositionnelle incluant la stabilisation des elements marins, et la precipitation d 'evaporites et de ciments calcitiques anddriques. Les 5 18OpD3 (-13.0 to 2.0%o), 87Sr/86Sr (0.7076 to 0.7079) et [Sr] (50 to 10000 ppm) de micro£chantillons des unites inferieures et superieures, et de ciments anedriques montrent deux tendences enveloppant l'ensemble des rdsultats. Ces tendences suggerent qu'un fluide non-radiogenique, evaporitique et un fluide radiogenique derive de roches clastiques, auraient affecte les sediments calcaires au cours de leur enfouissement progressif plus profond. Le fluide evaporitique aurait principalement affecte I'unite superieure de la formation. Les donnees de terrain, les observation microscopiques et les resultats geochimiques n'indiquent pas l'empreinte m6teorique attendue si une discordance existait au sommet de la formation. L'histoire diag6netique ici documentee, ainsi que Pexistence de calcite fibreuse ddveloppde le long de plans de cisaillement paralieies au litage supportent le modeie de detachement pour expliquer les omissions stratigra...

show abstract

Seawater Sr isotope variations through time: A procedure for constructing a reference curve to date and correlate marine sedimentary rocks

Cited by 66 publications

References 4 publications

Covariance of C- and O-isotopes with magnetic susceptibility as a result of burial diagenesis of sandstones and carbonates: an example from the Lower Devonian La Vid Group, Cantabrian Zone, NW Spain

Covariance of C- and O-isotopes with magnetic susceptibility as a result of burial diagenesis of sandstones and carbonates: an example from the Lower Devonian La Vid Group, Cantabrian Zone, NW Spain

The Phanerozoic δ88/86Sr record of seawater: New constraints on past changes in oceanic carbonate fluxes

Burial diagenesis model for the Macumber Formation on Cape Breton Island - implications for the tectonic evolution of the Windsor Group

Contact Info

Product

Resources

About