Construction of the Triassic and Jurassic portion of the Phanerozoic curve of seawater 87Sr/86Sr

Koepnick, Richard B.; Denison, Rodger E.; Burke, W. H.; Hetherington, E.A.; Dahl, David

doi:10.1016/0168-9622(90)90014-4

Cited by 93 publications

(58 citation statements)

References 36 publications

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“…0.0002 for the Mesozoic and Paleozoic (BURKE et al, 1982;KOEPNICK et al, 1985KOEPNICK et al, , 1990. The Neoproterozoic record is far less well established, but an improving data base confirms that this was an interval of extreme secular variation.…”

Section: Introductionmentioning

confidence: 78%

Strontium isotopic variations of Neoproterozoic seawater: Implications for crustal evolution

Asmerom

Jacobsen

Knoll

et al. 1991

Geochimica et Cosmochimica Acta

210

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Section: Introductionmentioning

confidence: 78%

Strontium isotopic variations of Neoproterozoic seawater: Implications for crustal evolution

Asmerom

Jacobsen

Knoll

et al. 1991

Geochimica et Cosmochimica Acta

210

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“…The high percentage of insoluble residues after the dissolution of bulk carbonate samples (Table 1) makes these data suspect. Some samples could have incorporated Sr from the noncarbonate sources (Koepnick et al, 1990). The consistency of the planktonic foraminifer 87 Sr/ 86 Sr results and the apparent lack of textural evidence for major secondary calcite replacement features suggest that foraminifer data reflect contemporaneous seawater more closely.…”

Section: Preservation Of Biogenic Calcite and Isotopic Ratiosmentioning

confidence: 99%

“…Sr-isotope analyses of most bulk carbonate samples were performed at the Mobil Research and Development Corporation (Dallas, TX) following the procedures described in Koepnick et al (1990). Sr-isotope analyses of all the foraminifer samples and a few bulk carbonate were conducted at Washington University (St. Louis, MI) according to the techniques outlined in Podosek et al (1991).…”

Section: Methodsmentioning

confidence: 99%

Strontium Isotope and Benthic Foraminifer Stable Isotope Results from Oligocene Sediments at Site 803

Barrera¹,

Baldauf²,

Lohmann³

1993

Proceedings of the Ocean Drilling Program

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Stratigraphic information from strontium, oxygen, and carbon isotopic ratios has been integrated with diatom and planktonic foraminifer datums to refine the Oligocene to early Miocene chemostratigraphy of Site 803. The Sr isotope results are based on analyses of mixed species of planktonic foraminifer and bulk carbonate samples.87 Sr/ 86 Sr ratios of bulk carbonate samples are, in most cases, less radiogenic than contemporaneous seawater. Estimated sediment ages based on planktonic foraminifer Sr/ 86 Sr ratios, using the Sr-isotope-age relation determined by Hess and others in 1989, are in moderately good agreement with the biostratigraphic ages. Chronological resolution is significantly enhanced with the correlation of oxygen and carbon isotope records to those of the standard Oligocene section tied to the Geomagnetic Polarity Time Scale at Site 522. Ages revised by this method and other published ages of planktonic foraminifer datums are used to revise the Oligocene stratigraphy of Site 77 to correlate the stable isotope records of Sites 77 and 803.Comparison of the Cibicidoides stable isotope records of Sites 77 and 574 with paleodepths below 2500 m in the central equatorial Pacific, and Site 803 at about 2000-m paleodepth in the Ontong Java Plateau reveals inversions in the vertical δ 18 θ gradient at several times during the Oligocene and in the early Miocene. The shallower water site had significantly-higher δ 18 θ values than the deeper water sites after the earliest Oligocene 18 O enrichment and before 34.5 Ma, in the late Oligocene from 27.5 to at least 25 Ma, and in the early Miocene from 22.5 to 20.5 Ma. It is not possible to ascertain if the δ 18 θ inversion persisted during the Oligocene/Miocene transition because the deeper sites have hiatuses spanning this interval. We interpret this pattern to reflect that waters at about 2000 m depth were cold and may have formed from mixing with colder waters originating in northern or southern high-latitude regions. The deeper water appear to have been warmer and may have been a mixture with warm saline waters from mid-or low-latitude regions. No apparent vertical δ 13 C gradient is present during the Oligocene, suggesting that the age difference of these water masses was small.

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“…Geochemical data, integrated with the C-, O-, and Srisotopic data, have been used to infer a metasedimentary petrogenetic affiliation for the studied rocks. The Föderata Group metacarbonates were very likely formed from Sr ratios from the Permian to the Cretaceous, with superimposed range of the curve of seawater (after Koepnick et al, 1990). sedimentary carbonate materials that were deposited in a saline, shallow-marine, low-energy environment.…”

Section: Discussionmentioning

confidence: 99%

“…Sr ratios in the Föderata Group metacarbonates were compared with data from various world localities using the study of Koepnick et al (1990) (Figure 12) Sr ratio are depicted slightly above the upper seawater line (Figure 12), which might be a result of metamorphic processes that could have influenced the redistribution of Rb and Sr. Since our data points plot within or nearby the band, we consider the Föderata Group metacarbonates to have a marine origin.…”

mentioning

confidence: 99%

Geochemistry and C, O, and Sr isotope composition of the Föderata Group metacarbonates (southern Veporicum, Western Carpathians, Slovakia):constraints on the nature of protolith and its depositional environment

Vďačný¹,

Růžička²,

Vozárová³

2016

Turkish J Earth Sci

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Major, trace, and rare earth element as well as C, O, and Sr isotope geochemistry is used to provide new insights into the characteristics and depositional environment of the protolith of the Föderata Group metacarbonates in the southern Veporicum cover sequence (Western Carpathians, Slovakia). The metacarbonates are characterized by high LOI and CaO and by small contents of various insoluble components. Among the trace elements investigated, only As, Ba, Co, Cu, Hg, Nb, Ni, Pb, Rb, Sb, Sr, Th, U, Y, Zn, and Zr display concentrations beyond their detection limits. The metacarbonates are strongly depleted in Rb, Ba, Th, Nb, Hf, Zr, and Y and enriched in U and Sr relative to the UCC. Chondrite-normalized rare earth element patterns of the metacarbonates show a moderate to strong fractionation in light rare earth elements over heavy rare earth elements and distinct negative Ce and Eu anomalies. Variation plots reveal several geochemical interrelationships, among which SiO 2 -Al 2 O 3 -K 2 O -TiO 2 -Ba -Nb -Rb -Zr are associated with the rock's silicate fraction. The carbonate fraction comprise CaO, MgO, and Sr. The overall geochemical and C-, O-, and Sr-isotopic signatures indicate that the metacarbonates developed from sedimentary carbonate materials that were deposited in a saline, shallowmarine, low-energy environment. The negative Ce anomaly (Ce/Ce* = 0.15-0.93) and the δ 13 C (2.36‰ to -3.34‰) values indicate warmer climatic conditions during deposition. The consistency of the rock's chemical properties could be attributed to the relative stability experienced during the parent sedimentary material's deposition.

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Construction of the Triassic and Jurassic portion of the Phanerozoic curve of seawater 87Sr/86Sr

Cited by 93 publications

References 36 publications

Strontium isotopic variations of Neoproterozoic seawater: Implications for crustal evolution

Strontium isotopic variations of Neoproterozoic seawater: Implications for crustal evolution

Strontium Isotope and Benthic Foraminifer Stable Isotope Results from Oligocene Sediments at Site 803

Geochemistry and C, O, and Sr isotope composition of the Föderata Group metacarbonates (southern Veporicum, Western Carpathians, Slovakia):constraints on the nature of protolith and its depositional environment

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