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Title: A geochemical approach to constraining the formation of glassy fallout debris from nuclear tests

Reprocessed earth material is a glassy nuclear fallout debris from near-surface nuclear tests. A geochemical approach to analysis of glassy fallout is uniquely suited to determine the means of reprocessing and shed light on the mechanisms of fallout formation. An improved understanding of fallout formation is of interest both for its potential to guide post-detonation nuclear forensic investigations and in the context of possible affinities between glassy debris and other glasses generated by high-energy natural events, such as meteorite impacts and lightning strikes. Our study presents a large major-element compositional dataset for glasses within aerodynamic fallout from the Trinity nuclear test (“trinitite”) and a geochemically based analysis of the glass compositional trends. Silica-rich and alkali-rich trinitite glasses show compositions and textures consistent with formation through melting of individual mineral grains—quartz and alkali feldspar, respectively—from the test-site sediment. Furthermore, the volumetrically dominant glass phase—called the CaMgFe glass—shows extreme major-element compositional variability. Compositional trends in the CaMgFe glass are most consistent with formation through volatility-controlled condensation from compositionally heterogeneous plasma. Radioactivity occurs only in CaMgFe glass, indicating that co-condensation of evaporated bulk ground material and trace device material was the main mechanism of radioisotope incorporation into trinitite. CaMgFe trinitite glasses overlap compositionallymore » with basalts, rhyolites, fulgurites, tektites, and microtektites but display greater compositional diversity than all of these naturally formed glasses. Indeed, the most refractory CaMgFe glasses compositionally resemble early solar system condensates—specifically, CAIs.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [2] ;  [5]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Nuclear and Radiochemicstry Group; New Mexico Tech, Socorrow, NM (United States). Dept. of Earth and Environmental Science
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Nuclear and Radiochemicstry Group
  3. Univ. of Wisconsin, Madison, WI (United States). Dept. of Geoscience
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Nuclear and Radiochemicstry Group; Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Physical Chemistry and Applied Spectroscopy Group
Publication Date:
Report Number(s):
LA-UR-15-24262
Journal ID: ISSN 0010-7999
Grant/Contract Number:
AC52-06NA25396; LA-UR-15-20991
Type:
Accepted Manuscript
Journal Name:
Contributions to Mineralogy and Petrology
Additional Journal Information:
Journal Volume: 172; Journal Issue: 1; Journal ID: ISSN 0010-7999
Publisher:
Springer
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS
OSTI Identifier:
1340913