Hermoso, Michael; McClelland, H L O; Hirst, J S; Minoletti, Fabrice; Bonifacie, Magali; Rickaby, Rosalind E M (2020): Isotopic values of of seawater and coccoliths at different size fractions from DSDP Hole 90-588A and 90-588C [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.914206
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Abstract:
Recent culture studies of living coccolithophores have established a biogeochemical framework for the use of the geochemical compositions of their calcite biominerals as proxies in palaeoceanography. Yet, questions remain regarding the transferability of such experimental data to fossil coccoliths. Here we analysed the carbon and oxygen isotopic composition of Miocene coccoliths to assess the suitability of such data for reconstructing the past environment. We found that the oxygen isotopic compositions of the relatively small Noelaerhabdaceae coccoliths gathered in the 3-5 μm fractions appear to be a suitable material to derive temperatures after a correction for a constant vital offset of 0.8‰. The interpretation of the isotopic signal of the relatively large Coccolithales coccoliths (5-8 μm fractions) is more complex, but supports results from cultures. The expression of the carbon and oxygen vital effect in coccoliths appears to be limited during the so-called Miocene Climate Optimum (MCO), a period of relatively elevated atmospheric pCO~2~. Subsequently, during the Miocene Climatic Transition (MCT; 14 Ma), which saw a decline in pCO~2, large carbon and oxygen vital effects were expressed in coccolith calcite. This phenomenon predates the postulated “Late Miocene Threshold” by approximately 4 Ma, and cannot be reconciled as a temporally-synchronous nor localised feature. Furthermore, we observed a statistically significant correlation between the oxygen and carbon offsets of the small relative to large coccoliths (hence, the vital effect per se) that is likely linked to variations in atmospheric CO~2~. This biogeochemical correlation further supports a forcing of the environment on the cellular physiology (growth rate and utilisation of intracellular carbon) and ultimately the magnitude of isotopic vital effects in fossil coccoliths.
Supplement to:
Hermoso, Michael; McClelland, H L O; Hirst, J S; Minoletti, Fabrice; Bonifacie, Magali; Rickaby, Rosalind E M (in press): Towards the use of the coccolith vital effects in palaeoceanography: A field investigation during the middle Miocene in the SW Pacific Ocean. Deep-Sea Research - Part I
Coverage:
Latitude: -26.111700 * Longitude: 161.226700
Date/Time Start: 1982-12-06T00:00:00 * Date/Time End: 1982-12-06T00:00:00
Minimum DEPTH, sediment/rock: 245.81 m * Maximum DEPTH, sediment/rock: 332.94 m
Event(s):
90-588A * Latitude: -26.111700 * Longitude: 161.226700 * Date/Time: 1982-12-06T00:00:00 * Elevation: -1533.0 m * Penetration: 344.4 m * Recovery: 84.3 m * Location: South Pacific/Tasman Sea/CONT RISE * Campaign: Leg90 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 18 cores; 103.8 m cored; 0 m drilled; 81.2 % recovery
90-588C * Latitude: -26.111700 * Longitude: 161.226700 * Date/Time: 1982-12-06T00:00:00 * Elevation: -1533.0 m * Penetration: 488.1 m * Recovery: 134.6 m * Location: South Pacific/Tasman Sea/CONT RISE * Campaign: Leg90 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 19 cores; 182.4 m cored; 0 m drilled; 73.8 % recovery
Parameter(s):
# | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
---|---|---|---|---|---|---|
1 | Event label | Event | Hermoso, Michael | |||
2 | DEPTH, sediment/rock | Depth sed | m | Hermoso, Michael | Geocode – mbfs | |
3 | AGE | Age | ka BP | Hermoso, Michael | Geocode | |
4 | δ18O, seawater, reconstructed | δ18Osw | ‰ SMOW | Hermoso, Michael | vs. VSMOW | |
5 | Coccoliths, δ18O | Cocco δ18O | ‰ PDB | Hermoso, Michael | Size fraction 12-20 µm | vs. VPDB; calcite |
6 | Coccoliths, δ18O | Cocco δ18O | ‰ PDB | Hermoso, Michael | Size fraction 10-12 µm | vs. VPDB; calcite |
7 | Coccoliths, δ18O | Cocco δ18O | ‰ PDB | Hermoso, Michael | Size fraction 8-10 µm | vs. VPDB; calcite |
8 | Coccoliths, δ18O | Cocco δ18O | ‰ PDB | Hermoso, Michael | Size fraction 5-8 µm | vs. VPDB; calcite |
9 | Coccoliths, δ18O | Cocco δ18O | ‰ PDB | Hermoso, Michael | Size fraction 3-5 µm | vs. VPDB; calcite |
10 | Coccoliths, δ18O | Cocco δ18O | ‰ PDB | Hermoso, Michael | Size fraction <3 µm | vs. VPDB; calcite |
11 | Coccoliths, δ13C | Cocco δ13C | ‰ PDB | Hermoso, Michael | Size fraction 12-20 µm | vs. VPDB; calcite |
12 | Coccoliths, δ13C | Cocco δ13C | ‰ PDB | Hermoso, Michael | Size fraction 10-12 µm | vs. VPDB; calcite |
13 | Coccoliths, δ13C | Cocco δ13C | ‰ PDB | Hermoso, Michael | Size fraction 8-10 µm | vs. VPDB; calcite |
14 | Coccoliths, δ13C | Cocco δ13C | ‰ PDB | Hermoso, Michael | Size fraction 5-8 µm | vs. VPDB; calcite |
15 | Coccoliths, δ13C | Cocco δ13C | ‰ PDB | Hermoso, Michael | Size fraction 3-5 µm | vs. VPDB; calcite |
16 | Coccoliths, δ13C | Cocco δ13C | ‰ PDB | Hermoso, Michael | Size fraction <3 µm | vs. VPDB; calcite |
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Size:
454 data points