The past decade has seen many new technologies spur the development of high-resolution geochemical research tools for paleoclimatology. These tools offer exciting opportunities to explore new proxies of past climate change with unprecedented spatial resolution. The result has been analyses of ultrasmall samples that provide access to information in terrestrial and marine archives at a temporal resolution—subannual and even subseasonal—that was previously inaccessible. Reconstructions with such high temporal resolution are critical for quantifying rates of environmental change during past abrupt climatic events and for constraining the rates and scope of future climate change.
The HiRes2015 workshop, hosted by the Wisconsin Secondary Ion Mass Spectrometer Laboratory (WiscSIMS) at the University of Wisconsin–Madison last spring, brought together 65 scientists with diverse expertise to discuss existing proxy records and plan directions for future research. New in situ technologies for obtaining high-resolution data were a recurring theme, with an eye toward enhancing data quality and synthesizing in situ geochemistry with imaging and structure of proxy materials. Participants presented data from secondary ion mass spectrometry (SIMS), nano-SIMS, laser ablation inductively coupled plasma mass spectrometry, atom probe tomography, micro-X-ray diffraction, and electron microscopy.
WiscSIMS scientists conducted tutorials on the theory and application of the CAMECA 1280 SIMS instrument to paleoclimate studies and coordinated a live look-in on an active δ18O analytical session (measuring the ratio of oxygen-18 to oxygen-16 isotopes) in order to clearly illustrate the capabilities and user interface of the sophisticated instrumentation.
Highlights of the workshop included the following:
- a stirring call to climate change research
- recent advances in culturing foraminifera and measuring their microscale to nanoscale geochemical variability
- an examination of the effects of the Toba supervolcano eruption on climate and human evolution as recorded in a Borneo speleothem
- the geochemical interpretations of mammalian tooth enamel and implications for understanding early hominids, with attention to the potential effects of diagenesis that cannot be characterized by conventional techniques
- paleorainfall records from soil-formed carbonates and the temporal and spatial importance of these records, particularly in now arid areas
- a demonstration that SIMS analyses performed on foraminiferal shells can improve records of surface ocean δ18O change during past climate states
The workshop confirmed that the field of chemical and isotopic microanalysis is advancing quickly, in some cases causing rejuvenation of research fields that have been limited by sample size. For many applications, a leap has been made from micrometer-scale to nanometer-scale measurements, representing improvements in time resolution of up to 3 orders of magnitude.
Repeat participants from the HiRes2013 meeting had developed new applications that seemed unlikely 2 years ago, revealing the importance of the exchange of ideas generated by this workshop. Combined with increased societal awareness of future climate change, rising sea levels, and new monthly global temperature records, the window of opportunity is widening for the development of high-resolution records of past climate change.
The workshop was funded by the National Science Foundation (NSF). WiscSIMS is an NSF-supported National Facility for Stable Isotope Geochemistry.
The abstracts and slides from talks at the workshop are available online.
—Ian J. Orland, John W. Valley, and Noriko T. Kita, Wisconsin Secondary Ion Mass Spectrometer Laboratory (WiscSIMS), Department of Geoscience, University of Wisconsin–Madison, Madison; email: [email protected]
Citation: Orland, I. J., J. W. Valley, and N. T. Kita (2015), High-resolution tools advance study of paleoclimate archives, Eos, 96, doi:10.1029/2015EO040911. Published on 8 December 2015.