Strontium isotopic variations in Jurassic and Cretaceous seawater

Jones, Charles E.; Jenkyns, Hugh C.; Coe, Angela L.; Stephen, Hesselbo P

doi:10.1016/0016-7037(94)90179-1

Cited by 303 publications

(194 citation statements)

References 49 publications

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“…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). 90% of our samples have Mn concentrations of less than 20μg/g and 71% of our samples have Fe concentrations of less than 150μg/g (Table A4 and Fig.…”

Section: Introductionmentioning

confidence: 72%

“…Consequently, relatively large volumes of water have to pass through carbonate rocks in order to significantly alter their Sr isotope composition. The resetting of diagenetically sensitive trace elements, such as Mn and Fe that have distribution coefficients greater than one (Dromgoole and Walter, 1990), does not automatically imply resetting of Sr isotopes (Jones et al, 1994a;Veizer, 1989).…”

Section: Sr Fractionation Factor (δ 88/86 Sr Cc-sw ) Between the Carbmentioning

confidence: 99%

“…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%

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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

107

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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.

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Section: Introductionmentioning

confidence: 72%

Section: Sr Fractionation Factor (δ 88/86 Sr Cc-sw ) Between the Carbmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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

107

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“…6, excluding data from the Subpolar Urals and North Siberia (Dzyuba et al, 2013;Price and Mutterlose, 2004) and excluding the data from La Chambotte (Morales et al, 2013) and the Kimmeridgian data from the Swiss Jura (Colombié et al, 2011). Belemnite oxygen isotope data from sources cited within the text; the Sr isotope record from Jones et al (1994); McArthur et al, (2004) and Bodin et al, (2009); humid and arid phases from Hallam et al (1991) and Ruffell et al (2002b) with Jurassic "dry event" transition phase (from Rameil, 2005) and eustatic sealevel curve from Haq (2014). Numeric ages, magnetostratigraphy and Tethyan Ammonite Zones are from GTS 2012 (Ogg and Hinnov, 2012a;2012b …”

Section: Figmentioning

confidence: 99%

“…8) (e.g., Jones et al, 1994;McArthur et al, 2004;Bodin et al, 2009;Wierzbowski et al, 2012) shows a trend towards more radiogenic values from a long-term low at the Callovian-Oxfordian boundary to a peak in the Barremian. This variation in Srisotopes possibly reflects a change in the balance of flux from relatively non-radiogenic Sr derived from mid-ocean ridge hydrothermal activity to relatively radiogenic Sr derived from continental weathering (including changes in both total riverine flux and the isotopic composition of the flux).…”

mentioning

confidence: 99%

Carbon cycle history through the Jurassic–Cretaceous boundary: A new global δ13C stack

Price

Főzy

Pálfy

2016

Palaeogeography, Palaeoclimatology, Palaeoecology

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We present new carbon and oxygen isotope curves from sections in the Bakony Mts. (Hungary), constrained by biostratigraphy and magnetostratigraphy in order to evaluate whether carbon isotopes can provide a tool to help establish and correlate the last system boundary remaining undefined in the Phanerozoic as well provide data to better understand the carbon cycle history and environmental drivers during the Jurassic-Cretaceous interval. We observe a gentle decrease in carbon isotope values through the Late Jurassic. A pronounced shift to more positive carbon isotope values does not occur until the Valanginian, corresponding to the Weissert event. In order to place the newly obtained stable to relatively stable δ 13 C values, compounded by a slope which is too slight. There is no clear isotopic marker event for the system boundary. The long-term gradual change towards more negative carbon isotope values through the Jurassic-Cretaceous transition has previously been explained by increasingly oligotrophic condition and lessened primary production. However, this contradicts the reported increase in 87 Sr/ 86 Sr ratios suggesting intensification of weathering (and a decreasing contribution of non-radiogenic hydrothermal Sr) and presumably a concomitant rise in nutrient input into the oceans.The concomitant rise of modern phytoplankton groups (dinoflagellates and coccolithophores) would have also led to increased primary productivity, making the negative carbon isotope trend even more notable. We suggest that gradual oceanographic changes, more effective connections and mixing between the Tethys, Atlantic and Pacific Oceans, would have promoted a shift towards enhanced burial of isotopically heavy carbonate carbon and effective recycling of isotopically light organic matter.These processes account for the observed long-term trend, interrupted only by the Weissert event in the Valanginian.

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Sea level and climate forcing of the Sr isotope composition of lateMioceneMediterranean marine basins

Schildgen

Cosentino

Frijia

et al. 2014

Geochem Geophys Geosyst

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Sr isotope records from marginal marine basins track the mixing between seawater and local continental runoff, potentially recording the effects of sea level, tectonic, and climate forcing in marine fossils and sediments. Sr/ 86 Sr analyses from the astronomically tuned Lower Evaporites in the central Apennines (Italy) allow us to explore the effect of glacio-eustatic sea level and precipitation changes on 87 Sr/ 86 Sr. Most variation in our data can be explained by changes in sea level, with greatest negative excursions from global seawater values occurring during relative sea level lowstands, which generally coincided with arid conditions in the Mediterranean realm. We suggest that this greater sensitivity to lowered sea level compared with higher runoff could relate to the inverse relationship between Sr concentration and river discharge. Variations in the residence time of groundwater within the karst terrain of the circum-Mediterranean region during arid and wet phases may help to explain the single (robust) occurrence of a negative excursion during a sea level highstand, but this explanation remains speculative without more detailed paleoclimatic data for the region.

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Strontium isotopic variations in Jurassic and Cretaceous seawater

Cited by 303 publications

References 49 publications

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

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

Carbon cycle history through the Jurassic–Cretaceous boundary: A new global δ13C stack

Sea level and climate forcing of the Sr isotope composition of lateMioceneMediterranean marine basins

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