Bebout, Gray E. et al. (2017) Nitrogen Concentrations and Isotopic Compositions of Seafloor-Altered Terrestrial Basaltic Glass: Implications for Astrobiology, Astrobiology, 18, 330-342, doi: 10.1089/ast.2017.1708. < 20200324155302-156458 > pub

Map on Earth or stone. Places and analyses are shown.

  • abstract:

    Observed enrichments of N (and the δ15N of this N) in volcanic glasses altered on Earth's modern and ancient seafloor are relevant in considerations of modern global N subduction fluxes and ancient life on Earth, and similarly altered glasses on Mars and other extraterrestrial bodies could serve as valuable tracers of biogeochemical processes. Palagonitized glasses and whole-rock samples of volcanic rocks on the modern seafloor (ODP Site 1256D) contain 3–18 ppm N with δ15Nair values of up to +4.5‰. Variably altered glasses from Mesozoic ophiolites (Troodos, Cyprus; Stonyford volcanics, USA) contain 2–53 ppm N with δ15N of −6.3 to +7‰. All of the more altered glasses have N concentrations higher than those of fresh volcanic glass (for MORB, 15N considerably higher than that of their unaltered glass equivalents (for MORB, −5 ± 2‰). Circulation of hydrothermal fluids, in part induced by nearby spreading-center magmatism, could have leached NH4+ from sediments then fixed this NH4+ in altering volcanic glasses. Glasses from each site contain possible textural evidence for microbial activity in the form of microtubules, but any role of microbes in producing the N enrichments and elevated δ15N remains uncertain. Petrographic analysis, and imaging and chemical analyses by scanning electron microscopy and scanning transmission electron microscopy, indicate the presence of phyllosilicates (smectite, illite) in both the palagonitized cracks and the microtubules. These phyllosilicates (particularly illite), and possibly also zeolites, are the likely hosts for N in these glasses.

  • doi: 10.1089/ast.2017.1708
  • modified at 16 h ago


(a) on Finnigan MAT 252 (at Lehigh University)
Tixhr 1382075063 thumb CYP-03 < 20170607132603-088163 >pub
  • classification: glass
  • physical-form: fraction
  • quantity (g): 5.67
  • description: Troodos ophiolite, Cyprus
  • modified at 2020-03-25
Tixhr 374525463 thumb CYP-04 < 20170607132609-983540 >pub
  • classification: glass
  • physical-form: fraction
  • quantity (g): 8.64
  • description: Troodos ophiolite, Cyprus
  • modified at 2020-03-25
Tixhr 484823791 thumb CYP-09 < 20170607132619-707236 >pub
  • classification: glass
  • physical-form: fraction
  • quantity (g): 6.64
  • description: Troodos ophiolite, Cyprus
  • modified at 2020-03-25
Tixhr 1176663996 thumb CYP-11 < 20170607132633-634020 >pub
  • classification: glass
  • physical-form: fraction
  • quantity (g): 6.33
  • description: Troodos ophiolite, Cyprus; this is sampled from margins of dyke rock.
  • modified at 2020-03-25
Tixhr47266182 thumb SFV-G3 < 20170607132511-977600 >pub
  • classification: glass
  • physical-form: fraction
  • quantity (g): 0.92
  • description: Stonyford volcanics, California
  • modified at 2020-03-25
Tixhr388590477 thumb SFV-G8 < 20170607132543-038242 >pub
  • classification: glass
  • physical-form: fraction
  • quantity (g): 1.82
  • description: Stonyford volcanics, California
  • modified at 2020-03-25
Tixhr818156543 thumb SFV-G4 < 20170607132523-831153 >pub
  • classification: glass
  • physical-form: fraction
  • quantity (g): 0.2
  • description: Stonyford volcanics, California
  • modified at 2020-03-25
name box-type global-id
A box for microtubule-bearing glass pub container 20170607132147-078535
binder of selected IPM publications 1 pub container 20200319102651-400217
name device size global-id
CYP-03 pub Finnigan MAT 252 (at Lehigh University) 2 20200325103840-844687
CYP-04 pub Finnigan MAT 252 (at Lehigh University) 2 20200325103841-564196
CYP-09 pub Finnigan MAT 252 (at Lehigh University) 2 20200325103841-951891
CYP-11 pub Finnigan MAT 252 (at Lehigh University) 2 20200325103841-922896
SFV-G3 pub Finnigan MAT 252 (at Lehigh University) 2 20200325103841-782468
SFV-G8 pub Finnigan MAT 252 (at Lehigh University) 2 20200325103841-996596
SFV-G4 pub Finnigan MAT 252 (at Lehigh University) 2 20200325103841-137376
name spots global-id
caption ID assembly stone
Table 2. Isotopic Data for Volcanic Glasses Cyprus and Stonyford Volcanics pub 20200325104057-599212 N (Gray, 2018) 7
manual
  • name
  • Bebout, Gray E.
  • Banerjee, N.R.
  • Izawa, M.R.M.
  • Kobayashi, Katsura
  • Lazzeri, K.
  • Ranieri, L.A.
  • Nakamura, Eizo