Journal article
Uranium series and beryllium isotope evidence for an extended history of subduction modification of the mantle below Nicaragua
Geochimica et Cosmochimica Acta, Vol.58(19), pp.4199-4212
10/01/1994
DOI: 10.1016/0016-7037(94)90273-9
Abstract
U-series nuclides, beryllium, and lead isotopes have been measured on historic lavas from eight volcanoes in Nicaragua. Low-Ti samples from northern Nicaragua have (230Th)(232Th) ratios from 2.23 to 2.56 and are enriched in 238U and 234U over 230Th by 1–16%. Those from southern Nicaragua have (230Th)(232Th)≈ 2.1 and have (238U)(230Th)= 1.0–0.9. High-Ti samples have intermediate (230Th)(232Th) ratios and are strongly enriched in 230Th. Lead isotopic data for all samples plot in the mantle array with 206Pb204Pb= 18.50–18.63. Th isotopic ratios for all samples imply source U/Th ratios that are significantly higher than those implied by lead isotopic ratios. All historic samples have (210Po)(230Th) and thus (226Ra)(230Th)> 1, suggesting that lavas erupt less than 8,000 y after generation. Thorium isotopic ratios for all volcanic samples correlate well with 10Be9Be and B/Be as well as with 87Sr86Sr and Ba/La ratios from the literature. (238U)(230Th) ratios do not correlate well with any of these ratios but rather anti-correlate with Th concentrations and published LaYb ratios.
Details
- Title: Subtitle
- Uranium series and beryllium isotope evidence for an extended history of subduction modification of the mantle below Nicaragua
- Creators
- Mark K. Reagan - University of IowaJulie D. MorrisEileen A. HerrstromMichael T. Murrell
- Resource Type
- Journal article
- Publication Details
- Geochimica et Cosmochimica Acta, Vol.58(19), pp.4199-4212
- DOI
- 10.1016/0016-7037(94)90273-9
- ISSN
- 0016-7037
- Language
- English
- Date published
- 10/01/1994
- Academic Unit
- Earth and Environmental Sciences
- Record Identifier
- 9983557559202771
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