/* DATA DESCRIPTION:
Citation:	Marino, Maria; Rodrigues, Teresa; Quivelli, Ornella; Girone, Angela; Maiorano, Patrizia; Bassinot, Franck (2025): Paleoproductivity proxies and alkenone precursors in the Western Mediterranean during the Early-Middle Pleistocene transition [dataset bundled publication]. PANGAEA, https://doi.org/10.1594/PANGAEA.982519
Abstract:	Multidisciplinary analyses (taxonomic analysis of coccolithophore assemblages, stable oxygen isotopes, marine and terrestrial biomarkers) have been carried out on sediments from Ocean Drilling Program Site 975 in the Algero-Balearic basin (38°53.8′ N, 4°30.6′ E), through late marine isotope stage (MIS) 20-19 (from 800 to 756 thousand years ago). The aim of the study was to compare coccolithophore paleoproductivity proxies, such as C37 alkenone concentration (ng/g) and nannofossil accumulation rate (NAR=coccoliths * cm- 2 * kyr-1), and understand their relationship with paleoceanographic condition and paleoenvironmental changes, alkenone-producing precursors and unsaturated C37 alkenone compounds (C37:2, C37:3, C37:4).
	Measurements of stable oxygen isotope analysis were performed on four to fifteen specimens of Globigerina bulloides (250–315 μm). These analyses were performed on an Isoprime 100 (Elementar) dual-inlet Isotope Ratio Mass Spectrometer (Elementar) at the Laboratoire des Sciences du Climat et de l'Environnement (LSCE, France). The results are expressed as δ18O vs V-PDB (in ‰) through calibration to international NBS standards. Quantitative analyses on coccolithophores were performed at the Dipartimento di Scienze della Terra e Geoambientali, Bari University (Italy), using a polarized light microscope at 1000 X magnification, and abundances were determined by counting at least 500 coccoliths of all sizes. Nannofossil dissolution index (DI) has been calculated as follows: small gephyrocapsids/(small gephyrocapsids + Calcidiscus leptoporus). Marine and terrestrial biomarkers have been processed at the Instituto Português do Mar e da Atmosfera (Portugal). The patterns of C37 alkenone concentration and NAR provided reliable information on past paleoproductivity changes. The Alkanol Preservation Index (API) obtained by the relative proportion of n-hexacosan-1-ol (C26OH) to the sum of C26OH plus n-nonacosane (C29) [API = C26OH/(C26OH + C29)], was used as a proxy of sea bottom ventilation in the basin. Sea surface temperature (SST) was estimated calculating the alkenone Uk'37 index that is based on the di- and tri-unsaturated alkenone ratio [(C37:2)/(C37:2 + C37:3)] and converted into temperature values using the global core top calibration of annual SST [Uk'37 = (0.033*SST) + 0.044], with a methodology uncertainty of ±0.5 ◦C. Tetra-unsaturated compound (C37:4) was considered as an indicator of lower temperature and low salinity waters and linked to polar and subpolar water influx into the Western Mediterranean.
Keyword(s):	Algero-Balearic basin; alkenone SST; Biomarkers; Coccolithophores; marine biomarkers; Oxygen isotopes; terrestrial biomarkers
Related to:	Marino, Maria; Rodrigues, Teresa; Quivelli, Ornella; Girone, Angela; Maiorano, Patrizia; Bassinot, Franck (2022): Paleoproductivity proxies and alkenone precursors in the Western Mediterranean during the Early-Middle Pleistocene transition. Palaeogeography, Palaeoclimatology, Palaeoecology, 601, 111104, https://doi.org/10.1016/j.palaeo.2022.111104
Project(s):	Ocean Drilling Program (ODP) (URI: https://www-odp.tamu.edu:443/)
Coverage:	LATITUDE: 38.896633 * LONGITUDE: 4.509883
	DATE/TIME START: 1995-05-14T00:00:00 * DATE/TIME END: 1995-08-19T00:00:00
Event(s):	161-975 * LATITUDE: 38.896633 * LONGITUDE: 4.509883 * DATE/TIME START: 1995-05-14T00:00:00 * DATE/TIME END: 1995-08-19T00:00:00 * ELEVATION: -2415.8 m * Penetration: 790.2 m * Recovery: 773.6 m * LOCATION: Western Basin * CAMPAIGN: Leg161 (URI: https://doi.org/10.2973/odp.proc.ir.161.1996) * BASIS: Joides Resolution (URI: https://www-odp.tamu.edu:443/resolutn.html) * METHOD/DEVICE: Composite Core (COMPCORE) * COMMENT: 85 cores; 790.2 m cored; 0 m drilled; 97.9% recovery
Comment:	This dataset was funded by a Geoscience PhD scholarship from University of Bari, Italy.
License:	Creative Commons Attribution 4.0 International (CC-BY-4.0) (URI: https://creativecommons.org/licenses/by/4.0/)
Size:	3 datasets
*/
/* TABULAR SUMMARY OF DATASETS LISTED IN THIS COLLECTION: */
Filename	Citation of child dataset
calcareous_nannofossils_ODP-975.tab	Marino, Maria; Rodrigues, Teresa; Quivelli, Ornella; Girone, Angela; Maiorano, Patrizia; Bassinot, Franck (2025): Calcareous nannofossils in the Western Mediterranean during the Early-Middle Pleistocene transition. https://doi.org/10.1594/PANGAEA.982552
marine_terrestrial_biomarkers_ODP-975.tab	Marino, Maria; Rodrigues, Teresa; Quivelli, Ornella; Girone, Angela; Maiorano, Patrizia; Bassinot, Franck (2025): Marine and terrestrial biomarkers in the Western Mediterranean during the Early-Middle Pleistocene transition. https://doi.org/10.1594/PANGAEA.982551
oxygen_isotopes_ODP-975.tab	Marino, Maria; Rodrigues, Teresa; Quivelli, Ornella; Girone, Angela; Maiorano, Patrizia; Bassinot, Franck (2025): Stable oxygen isotopes in the Western Mediterranean during the Early-Middle Pleistocene transition. https://doi.org/10.1594/PANGAEA.982549
