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Erhardt, Andrea M; Turchyn, Alexandra V; Dickson, J A D; Sadekov, Aleksey Y; Taylor, Paul D; Wilson, Mark A; Schrag, Daniel P (2019): Chemical composition of carbonate hardground cements [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.910001

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Published: 2019-12-12 • DOI registered: 2020-02-10

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Abstract:
Trace metal and isotopic ratios, including some rare earth elements, Mg/Ca, manganese and strontium concentrations, δ¹⁸O, δ¹³C, and ⁸⁷Sr/⁸⁶Sr, were analyzed in the carbonate cements from 17 Phanerozoic carbonate hardgrounds. The sensitivity of the geochemical signal to alteration depends on the geochemical analysis in question and the environmental water-rock ratio. Of these samples, only our modern sample has measurements consistent with primary precipitation from seawater; all other samples precipitated from chemically evolved seawater or were influenced by meteoric water, even if only minimally changed. The more recent samples from the Cenozoic had seawater ⁸⁷Sr/⁸⁶Sr. The Mesozoic samples, in contrast, did not preserve seawater ⁸⁷Sr/⁸⁶Sr, even though the Mg/Ca, δ¹⁸O, and δ¹³C values were consistent with precipitation from seawater. Finally, the Paleozoic samples preserved expected seawater ⁸⁷Sr/⁸⁶Sr, though REE and δ¹⁸O suggest primary precipitation was from evolved seawater. Additionally, we place our results in the context of open vs. closed system precipitation using transects of the Mg/Ca ratios across individual cements. Overall, we stress that one geochemical measurement provides only a partial record of fluid composition, but multiple measurements allow a potential understanding of the seawater geochemical signal.
Keyword(s):
carbonate hard grounds; Mg/Ca ratios; strontium isotopes
Coverage:
Median Latitude: 33.179768 * Median Longitude: 30.709373 * South-bound Latitude: 11.500000 * West-bound Longitude: -117.000000 * North-bound Latitude: 54.566670 * East-bound Longitude: 162.333330
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Size:
7 datasets

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Datasets listed in this publication series

  1. Erhardt, AM; Turchyn, AV; Dickson, JAD et al. (2020): (Table S2) Elemental data raw results and internal standard errors for hardground samples. https://doi.org/10.1594/PANGAEA.910864
  2. Erhardt, AM; Turchyn, AV; Dickson, JAD et al. (2020): (Table S3) Electron microprobe measurements analysis for hardgrounds. https://doi.org/10.1594/PANGAEA.910793
  3. Erhardt, AM; Turchyn, AV; Dickson, JAD et al. (2019): (Table 1) Age, location, and depositional environment information for hardgrounds. https://doi.org/10.1594/PANGAEA.910000
  4. Erhardt, AM; Turchyn, AV; Dickson, JAD et al. (2019): (Table 2) Lanthanum, cerium, praseodymium, neodymium and yttrium average shale-normalized values and cerium anomalies for hardground samples. https://doi.org/10.1594/PANGAEA.910307
  5. Erhardt, AM; Turchyn, AV; Dickson, JAD et al. (2019): (Table 3) Strontium, oxygen, and carbon isotopic measurements for hardground samples. https://doi.org/10.1594/PANGAEA.910005
  6. Erhardt, AM; Turchyn, AV; Dickson, JAD et al. (2019): (Table 4) Manganese, strontium, and magnesium concentrations, along with proposed formational fluid Mg/Ca ratios, for hardground samples. https://doi.org/10.1594/PANGAEA.910043
  7. Erhardt, AM; Turchyn, AV; Dickson, JAD et al. (2019): (Table S1) Laser ablation strontium isotope analysis for hardgrounds. https://doi.org/10.1594/PANGAEA.910312