Deep fracture fluids have been found in a mine in the Timmins, Ontario, area of the Canadian Precambrian Shield. Here we show that excesses of 124Xe, 126Xe and 128Xe in the Timmins mine fluids can be linked to xenon isotope changes in the ancient atmosphere and used to calculate a minimum mean residence time for this fluid of about 1.5 billion years. Further evidence of an ancient fluid system is found in 129Xe excesses that, owing to the absence of any identifiable mantle input, are probably sourced in sediments and extracted by fluid migration processes operating during or shortly after mineralization at around 2.64 billion years ago. We also provide closed-system radiogenic noble-gas (4He, 21Ne, 40Ar, 136Xe) residence times. Together, the different noble gases show that ancient pockets of water can survive the crustal fracturing process and remain in the crust for billions of years.
The datasets were originally published as supplementary files of the following publicaiton:
Holland, Greg, B. Sherwood Lollar, L. Li, G. Lacrampe-Couloume, G. F. Slater, and C. J. Ballentine. "Deep fracture fluids isolated in the crust since the Precambrian era." Nature 497, no. 7449 (2013): 357-360. http://www.nature.com/nature/journal/v497/n7449/abs/nature12127.html