Description: 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.
Global identifier:
Doi(
"10.1594/PANGAEA.910001",
)
Dataset
Origins: /Wissenschaft/PANGAEA
Tags: Zement ? Strontium ? Meerwasser ? Seltene Erden ? Metall ? Chemische Zusammensetzung ? Sensitivitätsanalyse ? Niederschlag ? Mg/Ca ratios ? carbonate hard grounds ? strontium isotopes ?
Bounding boxes: -117° .. 162.33333° x 11.5° .. 54.56667°
License: cc-by/4.0
Language: Englisch/English
Issued: 2019-12-12
Modified: 2020-02-10
Time ranges: 2019-12-12 - 2020-02-10
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