Palaeoclimate and climate systems facility
The facility comprises laboratories for processing marine sediment cores and sample preparation for geochemical analysis, a stable isotope laboratory and a high-resolution ICP-MS laboratory.
The labs house cold rooms suitable for storage of sediment cores; extensive wet areas equipped with fume hoods, DI water systems, and facilities for sediment sieving and generic geochemical processing; ample bench space with reflecting light microscopes for micropalaeontological analysis, and microbalances and further relevant equipment.
The stable isotope laboratory can provide analyses of the light isotopes 13C, 15N, and 18O in a range of materials. It is equipped with a Thermo MAT 253 with Kiel IV carbonate preparation device and a Thermo Delta V Advantage with Gasbench II and Flash EA CN analyser.
High-resolution ICP-MS laboratory
The high-resolution ICP-MS laboratory is optimized for the analysis of trace metal elements in carbonate (e.g. foraminifera, molluscs) and sea water samples, but it can address applications from a wide range of disciplines.
The laboratory is equipped with a Thermo Scientific™ ELEMENT XR™ HR-ICP-MS in combination with an Elemental Scientific SC-E2 Autosampler. The Element XR Element XR is a double focusing mass analyser (magnetic sector and electrostatic sector) which benefits from high resolution, a large dynamic range and precise analysis at low concentrations (ppt-ppq).
There are three clean rooms for the preparation of the samples and standards to be analysed on the Element XR. These have fume cupboards, ELGA ultra-pure water systems delivering Type I water (up to 18.2 MΩ·cm) and laminar flow workstations fitted with HEPA and PTFE ULPA filters.
Core processing laboratory
Coulter counter. One of the labs houses a Beckman Multisizer III, which utilizes the coulter principle or 'Electrical Sensing Zone' method to provide number, volume, mass and surface area distributions of suspended particles in a single measurement. It can measure particles in the range 0.4-1200µm.
How it has helped
The PACS facility provides essential data on the physical and chemical composition of the world's oceans from which we can reconstruct past climate change, and investigate how the climate system has responded to rapid perturbations.
We have reconstructed thermocline temperature and salinity for the period AD 818 to 1780 using paired δ18O and Mg/Ca ratio measurements of foraminifer shells from a marine sediment core south of Iceland. The reconstructed centennial-scale variations in hydrography correlate with variability in total solar irradiance (sunspot cycles). We inferred that low solar irradiance promotes the development of quasi-stationary high-pressure systems in the eastern North Atlantic, and that this process may have contributed to the consecutive cold winters documented in Europe during the Little Ice Age (10.1038/ngeo2094).
We showed that the occurrence of [human cultural] innovation during the Middle Stone Age of South Africa was tightly linked to abrupt climate change recorded in ocean sediments, which resulted from the bipolar seesaw behaviour of the Atlantic Ocean related to changes in the ocean circulation during the last glacial period. This strongly implies that innovational pulses of early modern human behaviour were climatically influenced and linked to the adoption of refugia (10.1038/ncomms2897).
We presented new benthic foraminiferal Mg/Ca, Li/Ca, and U/Ca records across the Oligocene-Miocene boundary (c. 23 Ma ago), which display a transient ~1‰ excursion in δ18O indicative of a substantial increase and subsequent decrease in ice volume on Antarctica. Such geological evidence for episodes of ice sheet retreat is difficult to reconcile with ice sheet models, which suggest that a large Antarctic Ice Sheet, once formed, was self-stabilizing due to its cold upper surface. Our results suggest that ice sheet retreat was associated with an input of carbon to the ocean-atmosphere system, and that carbon cycle feedback should be considered when evaluating the stability of ancient ice sheets (10.1130/G34422.1).