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A new helium isotope recored of the Paleocene-Eocene Thermal Maximum from ODP Site 198-1209 (S6)
No full textThe Paleocene-Eocene Thermal Maximum (PETM; around 56 Ma ago) is arguably the most intensively studied event of rapid greenhouse warming of the geological past. The duration and age of the PETM, however, remains vividly debated, limiting our understanding of the response of the Earth System dynamics to rapid warming. Here we present new extraterrestrial helium 3 (3HeET) data across the PETM at ODP Site 198-1209 (N Pacific) that document a drop in 3HeET fluxes from 0.56 ± 0.02 pcm³/cm²/ka ~1 Ma prior to the PETM to values of 0.37 ± 0.02 pcm³/cm²/ka before and after the PETM. Our 3HeET-based chronology, optimized through spectral analysis and orbital tuning, indicates a duration of 160±10 ka for the PETM body/core, consistent with previous 3HeET estimates from ODP Site 208-1266 (Walvis Ridge). The PETM started at the onset of a 100 ka eccentricity maxima at 56080 ka BP and ended abruptly during a marked decline in eccentricity at 55883 ka, providing strong support for an orbital trigger of both its onset and termination. The reevaluation of the 3HeET age models of the high paleo-latitude ODP Site 113-690 shows that the prominent sedimentary and carbon isotope steps at this site were controlled by obliquity instead of precession. Our revised chronology suggests that obliquity was also the dominant driver of the repeated drops to lower δ13C values during the PETM in otherwise precession-dominated low latitude sites, possibly reflecting the repeated destabilization of methane hydrate or permafrost carbon stocks at high latitudes.
This dataset contains the grayscale reflectance logs obtained on core photographs for ODP Site 198-1209A, B and C, new records of helium isotope and non-carbonate fraction data for ODP Site 198-1209 and the reconstructed apparent 3HeET fluxes (FET), instantaneous sedimentation rates (ISR) and ages. We also report new bulk carbonate carbon and oxygen stable isotope data for ODP Site 198-1209 that are included in a compilation of published bulk carbonate data from the same site along with their corresponding 3HeET ages. We include a compilation of published benthic foraminifera carbon and oxygen stable isotope data for ODP Site 198-1209 with their corresponding 3HeET ages. We also report a compilation of Fe and Ca concentrations, stable isotope data measured on bulk sediment, planktonic and benthic foraminifera from ODP Site 113-690 that are reported against a revised 3HeET-based age model we developed for this site using published 3HeET data and a revised 3HeET flux of 0.42 ± 0.02 pcm³/cm²/ka and an age of 55916 ka BP for point F (169.05 mbsf)
Soild phase porosity from site NB8 in the Ore Estuary (Bothnian Sea)
No full textPorewater depth profiles of ammonium, nitrate, sulfate, sulfide, dissolved iron, dissolved manganese, methane and oxygen; Solid phase depth profiles of total organic carbon, sequential iron and manganese extraction results of site NB8 in the Ore Estuary in the Bothnian Sea. (data published in doi:10.1021/acs.est.3c02023)
Age model of sediment core from Lake Prata (São Miguel, Azores, Portugal)
No full textThe location of the Azores Archipelago makes this group of islands an excellent setting for investigating past long-term temperature and precipitation changes in the central North Atlantic region. Lake Prata (37º48'23''N, 25°44'12''W; 520 m a.s.l.) is found on the island of São Miguel, more precisely in the western sector of the Picos fissure system, 5 km SE of the Sete Cidades caldera, and it fills the crater of a scoria cone older than 5000 years. The lake is currently a Sphagnum/Eleocaris-dominated peatland. In January 2021, a 4.5-m long core was collected from Lake Prata using a Russian corer with a 50 cm long and 7 cm diameter sampler. The core was packed in PVC trays and covered in plastic film before being transported to the CIBIO's paleolimnology laboratory (University of Azores). The core was dated using ¹⁴C and produced a multi-proxy dataset of geochemical and biological analyses that we used to uncover paleoenvironmental changes on Lake Prata in the last ca. 1200 years
Oxygen isotopes (δ18O) of sediment core from Lake Prata (São Miguel, Azores, Portugal)
No full textThe location of the Azores Archipelago makes this group of islands an excellent setting for investigating past long-term temperature and precipitation changes in the central North Atlantic region. Lake Prata (37º48'23''N, 25°44'12''W; 520 m a.s.l.) is found on the island of São Miguel, more precisely in the western sector of the Picos fissure system, 5 km SE of the Sete Cidades caldera, and it fills the crater of a scoria cone older than 5000 years. The lake is currently a Sphagnum/Eleocaris-dominated peatland. In January 2021, a 4.5-m long core was collected from Lake Prata using a Russian corer with a 50 cm long and 7 cm diameter sampler. The core was packed in PVC trays and covered in plastic film before being transported to the CIBIO's paleolimnology laboratory (University of Azores). The core was dated using ¹⁴C and produced a multi-proxy dataset of geochemical and biological analyses that we used to uncover paleoenvironmental changes on Lake Prata in the last ca. 1200 years
B/Ca, δ¹¹B and calcifying fluid carbonate chemistry reconstruction of Porites sp. fromTonga (TNI2)
No full textSamples were collected from two Porites sp. coral cores in the Southwestern Pacific, specifically at Nomuka Iki Island (Tonga). Parameters measured in this study include boron stable isotope analysis (δ11B) and Boron/Calcium (B/Ca) ratios. The Tonga coral core (TNI2) yielded 224 samples covering the period from 1777 to 2004 out of which 123 were analyzed for δ11B.
δ11B measurements were conducted on NuPlasma II MC-ICP-MS and boron was concentrated using the micro-distillation (sublimation) method. B/Ca was originally analyzed in every to every second millimeter resolution, providing approximately bimonthly resolution, on Analytik Jena PlasmaQuant Elite ICP-MS. That data was annualized for this study and here it is attached in its annual resolution. The carbonate chemistry of the calcifying fluid was reconstructed using δ11B and B/Ca ratios yielding reconstructions of pHcf (calcifying fluid pH), pHsw (seawater pH), [CO3²] (carbonate ion concentration), DIC (dissolved inorganic carbon), and Ωcf (aragonite saturation state). Reconstructions of [CO3²], DIC and Ωcf were calculated using boronsysarag (DeCarlo et al., 2018;doi:10.5194/bg-15-2819-2018) and seacarb (Gattuso et al., 2021; https://cran.r-project.org/web/packages/seacarb/index.html) packages in R statistical software (R Core team, 2021; https://www.r-project.org/foundation/)
Concentrations of sulfur compounds in surface waters of the Yangtze River Estuary in early spring (2018.3)
No full textSpringtime spatial distributions of biogenic sulfur compounds in the Yangtze River Estuary and their responses to seawater acidification and dust
No full textThe spatial distributions of dimethylsulfide (DMS), dimethylsulfoniopropionate (DMSP), and dimethylsulfoxide (DMSO) were investigated in the Yangtze River Estuary from 9 to 23 March, 2018. Besides, we analyzed the vertical distributions of DMS, DMSP, and DMSO in early spring. An onboard incubation experiment was also carried out to study how the production and release of biogenic sulfur compounds responded to simulated seawater acidification and dust deposition
Oxygen isotope ratios of planktonic and benthic foraminifera collected from marine sediment core KR05-15_PC01 and KR05-15_PL01
No full textA precise age model of marine sediment core is crucial for environmental studies of the past such as paleoceanography, paleoclimatology, and paleo-hazard studies. Here we report a dataset of oxygen isotope ratios of foraminifera collected from marine sediment cores recovered from the West Caroline Basin in the western equatorial pacific using a piston coring system of R/V Kairei in 2005 (KR05-15 PC01/PL01, 0.10°S 139.58°E, 3,226 m below sea level). The core depth 4.91–6.25 meters of 12.46-meter-long piston core (PC01), which corresponds to termination 2 (ca. 140–120 kyr ago), and a whole 0.53-m-long pilot core (PL01) were used for the measurement of oxygen isotopes of both planktonic (Globigerinoides ruber, Trilobus sacculifer) and benthic (Uvigerina spp.) foraminifera shells. The already published other datasets of oxygen isotopes of both planktonic and benthic foraminifera shells that were collected from the same sediment core (KR05-15 PC01) are also compiled
Processed sensible and latent heat flux for summer 2017 at the EastGRIP site on the Greenland Ice Sheet
No full textProcessed 10 minute surface sensible and latent heat flux measured at 160 cm above snow surface. The eddy covariance system included a Campbell Scientific CSAT3 and a Krypton Hygrometer KH20 which were directed into the mean wind. The latent heat flux was calculated assuming a latent heat of sublimation of 2835 J/g snow. The integration time was 10 minutes with the timestamps indicating the end of the averaging period