ALBERT

Description: This data set presents Th/U ages from a speleothem deposit in the Eastern Desert of Egypt at Saqia Cave and mean values of δ13C and δ18O for the respective speleothem growth phases. The presence and absence of speleothem deposition in (hyper-) arid environments can be regarded as an on-off situation. Deposition take place during phases of sufficient water availability and vegetation growth (“on”), whereas speleothem growth is absent under an arid climate (“off”). δ13C and δ18O isotope composition of each dated section is used for insights into the moisture source in the Eastern Desert and possible changes in the dominance of C3/C4 type vegetation. Sample collection was done as part of the Collaborative Research Centre 806 “Our Way to Europe”. Uranium-series dating was conducted at the Institute for Environmental Physics at Heidelberg University with isotope measurements using either thermal ionisation mass spectrometry (TIMS Finnigan MAT 262 RPQ) or multi-collector inductively coupled-plasma mass spectrometry (MC-ICPMS, Thermo Scientific Neptune Plus. Measurement of δ13C and δ18O using a KIEL IV carbonate device connected to a MAT253 gas mass spectrometer installed at the Institute for Geology and Mineralogy in Cologne. Th/U ages range from 185.7 ± 4.3 ka to 83.2 ± 2.1 ka, with most of the dating's fall into MIS 5 (18 out of 21) and cover all substages of MIS 5. The δ18O signature from Saqia Cave ranges between −10.90‰ and −11.73‰ with a mean of −11,22 ± 0,29‰. δ13C is more variable ranging between −2,58‰ and −7.07‰ with a mean value of −5.67 ± 1.2‰. δ13C values during MIS 5e are lower during MIS 5e and higher during MIS 5d and 5b, although absolute lowest δ13C values from one sample of −7.6‰ exists during MIS 5d.

Description: This data presents high precision Th/U ages from seep carbonates obtained from a 5-meter-long rock core (GeoB 23225-1, MeBo24) collected by the sea floor drill rig MARUM-MeBo200 in Yam Seep, SW offshore Taiwan during SO266, RV Sonne. The dating results provide records of over 40 thousand years old gas seepage and an unconventional precipitation sequence throughout the 5-meter downcore. The oldest age presents at ~192 cmbsf and the youngest age at the lower end of the core (~490 cmbsf). It provides insights into gas seepage episodes at active margin as well as precipitation sequences influenced by fracturing. Uranium and thorium isotope measurements were performed at the Institute of Environmental Physics multi-collector ICPMS facility in Heidelberg, which hosts a ThermoFisher Neptuneplus MC-ICPMS following the method of Wefing et al., (2017) and Frank and Hemsing (2021). Coordinate GeoB 23225-1 (Lat. Lon.): 22° 03.487' 119° 47.979'; Water depth: 1352 mbsl.

Description: This dataset contains 48 U-Th ages of 14 speleothems used to reconstruct past sea level between 9ka and 421ka ago. They were collected from submerged caves in an area (〈20 km) around Tulum, Quintana Roo, Mexico (20.2°N, 87.5°W) at elevations between 0.0 m a.s.l and -28.7 m a.s.l. The speleothems were collected in situ and their elevation was measured with a dive computer (+-0.1m) at the base of the speleothem. Speleothem length ranges between 2 cm and 34 cm. The measurements were carried out by a multi-collector inductively coupled plasma mass spectrometer (ThermoFisher Neptune Plus).

Description: We present results of Th/U dating, stable isotope and trace element data from a speleothem from Puerto Rico. Th/U dating was performed using isotope dilution MC-ICPMS. Activity ratios were corrected for initial Th assuming an detrital weight ratio 232Th/238U = 0.154 ± 0.038 (corresponding to an activity ratio of the detritus in secular equilibrium of (230Th/232Th)detr = 19.79 ± 4.93), and secular equilibrium of the detritus. Ages are calculated using the decay constants by Cheng et al. (2000)). Uncertainties are given as 2σ- range, and do not include half-life uncertainties. Th/U dating shows that stalagmite PR-LA-1 covers the period from 15.4 to 46.2 ka with a growth interruption between 35.5 and 41.1 ka. Stable isotope samples were drilled with a spatial resolution of 1 mm and measured using an IRMS equipped with a Gasbench. Element/Calcium ratios of the speleothem were measured by laser ablation ICPMS and were reduced to the resolution of the stable isotope records.

Description: This data presents high precision Th/U ages from cold-water corals obtained from sediment cores up to 70 m long and collected by the sea floor drill rig MARUM-MeBo70 in the western Mediterranean Sea. The drill records provided new insights into the initiation of the Mediterranean coral mounds as the base of the 60-m-high Dragon mound was penetrated and dated to the Mid-Pleistocene (~390 ka). The coral ages document mound development pulses, which are remarkably coherent with precession-driven changes in African hydroclimate. The data supports studies on the relevance of past changes in continental hydroclimate and their implications on oceanic processes including the complex processes leading to the aggradation of cold-water coral mounds.

Description: The radiocarbon analysis of uranium-thorium-dated cold-water corals (CWCs) provides an excellent opportunity for qualitative reconstruction of past ocean circulation and water mass aging. While mid-depth water mass aging has been studied in the Atlantic Ocean, the evolution of the thermocline, tightly coupled to the atmosphere, is still largely unknown. Here we present a combined 14C and 230Th/U age record obtained from thermocline dwelling CWCs with partially centennial resolution over the last 32 ka at various locations in the central and east Atlantic Ocean (Azores Front, Mauritania, Angola), as well as in the Alboran Sea.