Facility Support: The WiscSIMS National Ion Microprobe

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

This grant supports WiscSIMS as a National Facility for Stable Isotope Geochemistry. WiscSIMS includes an IMS-1280 ion microprobe that is optimized for analysis of stable isotopes (H, Li, B, C, N, O, Mg, Si, S, Cl, Ca, and Fe). WiscSIMS has developed unique capabilities for precise and accurate analysis of isotope ratios from small to ultra small spots. The ability to analyze small spots (1-10 microns) in situ from microscope mounts allows data to be put in context with imaging and other forms of analysis. The availability of these new in situ capabilities has led to many exciting discoveries and is causing revolutionary changes in areas of geochemistry. The range and pattern of isotope variation can finally be determined from small objects that were formerly homogenized by analysis of bulk or powdered samples such as zircons, microfossils, and diagenetic cements. New and surprising information of fundamental importance has been found in many areas. For instance, high-resolution studies of continental paleoclimate had been limited to resolution at decade- to century-scale by conventional sampling techniques and yet ice-core records show that extreme shifts in climate can occur in less than 10 years. Recently, SIMS analysis of stalagmites has resolved changes in oxygen isotope ratio for one month or less, providing a record of seasonality and annual-scale climate. WiscSIMS has published proof-of-concept studies of many proxies of paleoclimate including speleothems, foraminifera, mollusks, fish otoliths, and calcretes and plans others including diatoms and biogenic phosphates. The broader impacts of this project include new applications of stable isotope geochemistry to problems of societal concern; public education; and training in geochemistry at undergraduate to post-doc level, including under-represented groups. In the first five years of operation, over 130 scientists have worked with WiscSIMS from 60 different universities and research institutes.