Seawater rare-earth element patterns preserved in apatite of Pennsylvanian conodonts?

Bright, Camomilia A.; Cruse, Anna M.; Lyons, Timothy W.; MacLeod, Kenneth G.; Glascock, Michael D.; Ethington, Raymond L.

doi:10.1016/j.gca.2008.12.014

Cited by 76 publications

(39 citation statements)

References 72 publications

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“…MREE enrichment is rather strong (most samples yield Sm N / Yb N > 1.0; Fig. 4), suggesting the presence of phosphate in the sediment or the influence of pore waters previously in contact with phosphate (Kidder and EddyDilek, 1994;Bright et al, 2009). …”

Section: Weathering Rate Changesmentioning

confidence: 99%

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Amelioration of marine environments at the Smithian–Spathian boundary, Early Triassic

et al. 2015

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Abstract. The protracted recovery of marine ecosystems following the Permian-Triassic mass extinction may have been caused, in part, by episodic environmental and climatic crises during the Early Triassic, among which the SmithianSpathian boundary (SSB) event is conspicuous. Here, we investigate the SSB event in the Shitouzhai section, Guizhou Province, South China, using a combination of carbonate carbon (δ 13 C carb ) and carbonate-associated sulfate sulfur isotopes (δ 34 S CAS ), rare earth elements, and elemental paleoredox and paleoproductivity proxies. The SSB at Shitouzhai is characterized by a +4 ‰ shift in δ 13 C carb and a −10 to −15 ‰ shift in δ 34 S CAS , recording negative covariation that diverges from the positive δ 13 C carb -δ 34 S CAS covariation that characterizes most of the Early Triassic. This pattern is inferred to reflect an increase in organic carbon burial (e.g., due to elevated marine productivity) concurrently with the oxidation of isotopically light H 2 S, as the result of enhanced vertical advection of nutrient-and sulfide-rich deep waters to the ocean-surface layer. Enhanced upwelling was likely a response to climatic cooling and the reinvigoration of globalocean overturning circulation at the SSB. Coeval decreases in chemical weathering intensity and detrital sediment flux at Shitouzhai are also consistent with climatic cooling. A decline in marine biodiversity was probably associated with the late Smithian thermal maximum (LSTM) rather than with the SSB per se. The SSB thus marked the termination of the extreme hothouse conditions of the GriesbachianSmithian substages of the Early Triassic and is significant as a record of accompanying climatic, environmental, and biotic changes. The ultimate cause of the SSB event is uncertain but may have been related to a reduction in intrusive magmatic activity in the Siberian Traps large igneous province.

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Section: Weathering Rate Changesmentioning

confidence: 99%

“…However, carbonate sediments containing even a minor amount of clay minerals tend to acquire a terrigenous REE signal characterized by high REE and strong LREE or MREE enrichment (Sholkovitz and Shen, 1995;Bright et al, 2009). At Shitouzhai, REE exhibits a strong positive correlation with .…”

Section: Weathering Rate Changesmentioning

confidence: 99%

Amelioration of marine environments at the Smithian–Spathian boundary, Early Triassic

et al. 2015

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“…These conodont-based studies suggested that the REE composition of seawater has not significantly changed during the Phanerozoic (Wright et al, 1984(Wright et al, , 1987Shields and Webb, 2004). However, preservation of biogenic phosphate has been challenged by a number of studies (e.g., Shields and Webb, 2004;Bright et al, 2009;Kocsis et al, 2010), which seriously opens the static seawater-REE conclusions based on conodont REE contents. In light of only two blMC REE datasets for the geologic past (Eocene and Silurian), we prefer to defer any further and detailed discussion on the potential secular variation of seawater REE content to a future time when more results may be available to us.…”

Section: Secular/extrinsic Environmental Ree Seawater Variationmentioning

confidence: 99%

“…Among the commonly studied materials are foraminiferas (Palmer, 1985 ), corals (Scherer and Seitz, 1980;Sholkovitz and Shen, 1995), other carbonate allochems (e.g., Nothdurft et al, 2004), conodonts (e.g., Wright et al, 1987), fish teeth (Grandjean et al, 1987), reptile teeth (Picard et al, 2002), phosphate , chert (Murray et al, 1992), and reefal microbialites (Webb and Kamber, 2000). However, to some degree all of these potential proxies suffer from problems that complicate their REE signals and thus the subsequent interpretation of the seawater composition and other oceanographic processes (Webb and Kamber, 2000;Bright et al, 2009). The foremost concern is the loss and/or overprinting of original REE's trends and compositions due to scavenging processes at or near the sediment pore-water interface (e.g., Banner et al, 1988;Webb et al, 2009) or contamination by terrigenous detritus (Webb and Kamber, 2000;Negrel et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Biogenic and abiogenic low-Mg calcite (bLMC and aLMC): Evaluation of seawater-REE composition, water masses and carbonate diagenesis

et al. 2011

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Biogenic low-Mg calcite (brachiopods) Burial calcite cements lREE, REESN seawater compositions Diagenetic lREE and REEsN variations The l;REE and shale-normalized (PAAS) REEsN values of modern brachiopods (biogenic low-Mg calcite: blMC) represented by several species from high-to low latitudes, from shallow-to deep waters and from warm-and cold-water environments, define three distinct average 'seawater' trends. The warm-and cold-water brachiopods define two indistinguishable (p < O.OSO) groups that mimic open -ocean seawater REE chemistry, exhibiting the typical LREE enrichment with a slightly positive to negative Ce anomaly followed by an otherwise invariant series. Other recent brachiopods from an essentially siliciclastic seabed environment are distinct in both l;REE and REEsN trends from the previous two populations, showing a slight enrichment in the MREEs and an increasing trend in the HREEs. Other groups of modern brachiopods are characterized by elevated REEsN trends relative to the 'normal'groups as well as by complexity of the series trends.The most characteristic feature is the decrease in the HREEs in these brachiopods from areas of unusual productivity (i.e., such as upwelling currents, fluvial input and aerosol dust deposition). Preserved brachiopods from the Eocene and Silurian exhibit REEsN trends and Ce anomalies similar to that of the 'open-ocean' modern brachiopods, although, their enriched l;REE concentrations suggest precipitation ofblMC influenced by extrinsic environmental conditions. Preservation of the bLMC was tested by comparing the l;REE and REEsN trends of preserved Eocene brachiopods to those of Oligocene brachiopods that were altered in an open diagenetic system in the presence of phreatic meteoric-water. The altered blMC is enriched by approximately one order of magnitude in both l;REE and REEsN trends relative to that in blMC of their preserved counterparts. Similarly, the l;REE and REEsN of preserved Silurian brachiopod blMC were compared to those of their enclosing altered lime mudstone, which exhibits features of partly closed system, phreatic meteoric-water diagenesis. Despite these differences in the diagenetic alteration systems and processes, the l;REEs and REEsN trends of the blMC of altered brachiopods and of originally mixed mineralogy lime mudstones (now diagenetic low-Mg caldte) are enriched by about one order of magnitude relative to those observed in the coeval and preserved blMC. In contrast to the changes in l;REE and REEsN of carbonates exposed to phreatic meteoric-water diagenesis, are the REE compositions oflate burial calcite cements precipitated in diagenetically open systems from burial fluids. The l;REE and REEsN trends of the burial cements mimic those of their host lime mudstone, with all showing slight LREE enrichment and slight HREE depletion, exhibiting a 'chevron' pattern of the REEsN trends.The overall enrichment or depletion of the cement REEsN trends relative to that of their respective host rock material reflects not only the openness of the diag...

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“…Concentrations of trace elements in vertebrate hard parts have hitherto commonly been normalised to PAAS (the Post-Archaean average Australian sedimentary rock; e.g., Kemp and Trueman, 2003;Lécuyer et al, 2003;Labs-Hochstein and MacFadden, 2006;Iliopoulos et al, 2010) or to NASC (the North American shale composite; Gromet et al, 1984;e.g., Girard and Lécuyer, 2002;Bright et al, 2009;Grandstaff and Terry, 2009). These common ways of normalisation appear to be reasonable if the bone-bearing rocks have a similar chemical composition to PAAS and NASC, or at least similar ratios between elements.…”

Section: Introductionmentioning

confidence: 99%

Variability of trace element uptake in marine reptile bones from three Triassic sites (S Poland): Influence of diagenetic processes on the host rock and significance of the applied methodology

Kowal-Linka

Jochum

2015

Chemical Geology

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Seawater rare-earth element patterns preserved in apatite of Pennsylvanian conodonts?

Cited by 76 publications

References 72 publications

Amelioration of marine environments at the Smithian–Spathian boundary, Early Triassic

Amelioration of marine environments at the Smithian–Spathian boundary, Early Triassic

Biogenic and abiogenic low-Mg calcite (bLMC and aLMC): Evaluation of seawater-REE composition, water masses and carbonate diagenesis

Variability of trace element uptake in marine reptile bones from three Triassic sites (S Poland): Influence of diagenetic processes on the host rock and significance of the applied methodology

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