Duque-Castaño, Monica; Voelker, Antje H L; Andersen, Nils (2026): Sample preparation parameters and stable carbon and oxygen isotope ratios of Globigerina bulloides and Cibicidoides wuellerstorfi from IODP Sites 306-U1313 and 306-U1312 in the North Atlantic during Marine Isotope Stages (MIS) 36 to 46 [dataset]. PANGAEA, https://doi.pangaea.de/10.1594/PANGAEA.995722 (DOI registration in progress)

This combined dataset contains sample preparation parameters and stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotope measurements from IODP Sites 306-U1312 (42°50.2′N, 23°38.2′W; 3554 m water depth) and 306-U1313 (41°0.08′N, 32°57.4′W; 3426 m water depth), located north of the Azores Islands. The record spans Marine Isotope Stages (MIS) 36 to 46 during the Early Pleistocene and includes wet weight, dry weight, coarse fraction weight, and stable isotope data obtained from planktonic and benthic foraminifera. Sediment samples were processed following the standard procedures of the Sedimentology and Micropaleontology Laboratory of the Divisão de Geologia e Georecursos Marinhos (DivGM), Instituto Português do Mar e da Atmosfera (IPMA). Samples were weighed before and after freeze-drying to determine dry weight, washed through a 63 μm sieve, and the coarse fraction was dried and weighed. Stable carbon (δ¹³C) and oxygen (δ¹⁸O) isotope measurements were performed on the planktonic foraminifera Globigerina bulloides and the benthic foraminifera Cibicidoides wuellerstorfi at the Leibniz Laboratory for Radiometric Dating and Stable Isotope Research (Kiel University, Germany) using a Finnigan MAT 253 mass spectrometer coupled to a Kiel IV carbonate preparation device. Isotope values are reported relative to the Vienna Pee Dee Belemnite (VPDB) standard. The age model for IODP Site U1312 is based on correlation of the benthic δ¹⁸O record of Cibicidoides wuellerstorfi to the LR04 benthic isotope stack, whereas the chronology of IODP Site 306-U1313 is based on correlation of the planktonic δ¹⁸O record of Globigerina bulloides to the high-resolution isotope record from IODP Site 339-U1385, which is aligned to the LR04 benthic isotope stack. The dataset provides sample preparation parameters and stable isotope records from IODP Sites 306-U1312 and 306-U1313, forming a comprehensive archive for paleoceanographic and micropaleontological studies of the Early Pleistocene North Atlantic.