NERC Argon Isotope Facility

NERC Argon Isotope Facility

Facility Background

The temporal resolution of the stratigraphic record, the only account of the 4.6 billion years of geological history, is the primary control on the complexity of questions scientists can ask about the Earth, its evolution and resultant habitability. As a consequence of the scientific pursuit to temporally dissect the geological record and decode Earth history, the NERC Argon Isotope Facility (AIF) was established through community demand nearly 20 years ago. Today the AIF is regarded as a leading international authority in geochronology, houses the most extensive range of analytical tools dedicated to the 40Ar/39Ar technique throughout Europe, and has the capability of dating K-bearing materials that were formed during Solar System accretion or rocks and minerals erupted during historical times.

The AIF has spent many years fine-tuning noble gas mass spectrometer techniques and different approaches to high-precision 40Ar/39Ar geochronology to give the UK user community access to a state-of-the-art 40Ar/39Ar dating laboratory.

Although AIF dates rocks from every Era of Earth History, we as a NERC Facility, specifically aim to define the template for collection of robust, accurate and highly precise 40Ar/39Ar ages from a variety of geologically young materials to support NERC science. For example, AIF establish dates and rates for the expansion of humans from Africa 1, facilitates temporal integration of palaeoclimate signals to allow investigation of past global climate change 10, determine timescales and frequencies of volcanic activity and super-eruptions to mitigate risk to the general populous 6, reconstruct timescales of fluid-rock interaction with respect to the mineralisation of mineable resources 17 and generation of hydrocarbons 11. As such, the Facility ethos is strongly aligned with the evolving NERC Strategy with output having direct societal and economic benefits to the UK and beyond.

However, as a versatile Facility that prides itself on being responsive to community demand, the AIF maintains scientific capability and intellectual leadership in deep time geochronology, for example, in studies of mass extinctions 16, geochemical evolution of the atmosphere and oceans 14 15, changes to ocean circulation 2, dating of ancient volcanic eruptions 4, geomagnetism and inner core processes 7, resolution of the interplay between climate and tectonics 5.

On the international stage, the AIF also leads UK 40Ar/39Ar efforts in the EarthTime initiative, conducts community service in the preparation of standards 12, is making pioneering measurements to improve our understanding of the uncertainties associated with the 40Ar/39Ar approach 13 whilst constantly developing novel approaches to noble gas mass spectrometry 9 and refining the constants we rely on for radio-isotopic dating 8 and even everyday life 3.

The AIF is internationally established as a cutting-edge dating facility, due to the expertise and experience of AIF personnel, the quality of its scientific output (peer-reviewed publications, PhD theses, conference presentations), technical innovation and training of chronology-literate scientists.

 

References:

  1. Adler, D. S. et al. Early Levallois technology and the Lower to Middle Paleolithic transition in the Southern Caucasus. Science 345, 1609-1613 (2013).
  2. Dalziel, I. W. D. et al. A potential barrier to deep Antarctic circumpolar flow until the late Miocene? Geol 41, 947-950 (2013).
  3. de Podesta, M. et al. A low uncertainty measurement of the Boltzmann constant. Metrologia, 50, 354-364 (2013).
  4. Ellis, B. S., Mark, D. F., Pritchard, C. J. & Wolff, J. A. Temporal dissection of the Huckleberry Ridge Tuff using the 40Ar/39Ar dating technique. Quaternary Geochronology 9, 34–41 (2012).
  5. Henderson, A. L., Najman, Y., Parrish, R., Mark, D. F. & Foster, G. L. Constraints to the timing of India–Eurasia collision; a re-evaluation of evidence from the Indus Basin sedimentary rocks of the Indus–Tsangpo Suture Zone, Ladakh, India. Earth Science Reviews 106, 265–292 (2011).
  6. Hicks, A., Barclay, J., Mark, D. F. & Loughlin, S. Tristan da Cunha: Constraining eruptive behavior using the 40Ar/39Ar dating technique. Geol 40, 723–726 (2012).
  7. Mark, D. F. et al. Anchoring the Pleistocene Geomagnetic Polarity Timescale. Quaternary Geochronology (in review).
  8. Mark, D. F., Stuart, F. M. & de Podesta, M. New high-precision measurements of the isotopic composition of atmospheric argon. Geochimica et Cosmochimica Acta 75, 7494–7501 (2011).
  9. Mark, D. F., Barfod, D., Stuart, F. M. & Imlach, J. The ARGUS multicollector noble gas mass spectrometer: Performance for 40Ar/39Ar geochronology. Geochem. Geophys. Geosyst. 10 (2009).
  10. Mark, D. F. et al. A high-precision 40Ar/39Ar age for the Young Toba Tuff and dating of ultra-distal tephra: forcing of Quaternary climate and implications for hominin occupation of India. Quaternary Geochronology 21, 90–103 (2014).
  11. Mark, D. F., Parnell, J., Kelley, S. P., Lee, M. R. & Sherlock, S. C. 40Ar/39Ar dating of oil generation and migration at complex continental margins. Geol 38, 75–78 (2010).
  12. Morgan, L. E., Mark, D. F., Imlach, J., Barfod, D. & Dymock, R. FCs-EK: a new sampling of the Fish Canyon Tuff 40Ar/39Ar neutron flux monitor. Geological Society, London, Special Publications 378, 63–67 (2014).
  13. Morgan, L. E. et al. A metrological approach to measuring 40Ar* concentrations in K‐Ar and 40Ar/39Ar mineral standards. Geochem. Geophys. Geosyst. 12 (2011).
  14. Parnell, J., Mark, D. F., Frei, R., Fallick, A. E. & Ellam, R. M. 40Ar/39Ar dating of exceptional concentration of metals by weathering of Precambrian rocks at the Precambrian–Cambrian boundary. Precambrian Research 246, 54–63 (2014).
  15. Parnell, J., Boyce, A. J., Mark, D., Bowden, S. & Spinks, S. Early oxygenation of the terrestrial environment during the Mesoproterozoic. Nature 468, 290–293 (2010).
  16. Renne, P. R. et al. Time scales of critical events around the Cretaceous-Paleogene boundary. Science 339, 684–687 (2013).
  17. Rice, C. M., Steele, G. B., Barfod, D. N., Boyce, A. J. & Pringle, M. S. Duration of magmatic, hydrothermal, and supergene activity at Cerro Rico de Potosi, Bolivia. Economic Geology 100, 1647–1656 (2005).