Characterization of lacustrine iron sulfide particles with proton-induced X-ray emission

Journal Article · Tue Dec 01 00:00:00 EST 1992 · Limnology and Oceanography; (United States)

DOI:https://doi.org/10.4319/lo.1992.37.8.1770· OSTI ID:6614790

Davison, W ^[1]; Grime, G W ^[2]; Woof, C ^[3]

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1. Lancaster Univ. (United Kingdom)
2. Univ. of Oxford (United Kingdom)
3. Inst. of Freshwater Ecology, Ambleside (United Kingdom)

Black particles, collected by filtration (1.2-[mu] pore size) from the anoxic waters of a soft-water lake, were examined by a scanning proton microprobe which permitted quantitative elemental analysis by proton-induced X-ray emission (PIXE) and Rutherford backscattering (RBS). There was a uniform distribution of sulfur across the filter, but Fe, and to a lesser extent, Mn, was localized in [approximately]5-[mu]m diameter clusters. Elemental analysis with 1-[mu]m-diameter beams revealed that the Fe clusters were mainly comprised of iron oxides. Iron sulfide material not in the Fe clusters had stoichiometric proportions of Fe[sub 1.0]S[sub 0.60]P[sub 0.60]Ca[sub 0.24]K[sub 0.14]. Although a purely biogenic origin for P, Ca, and K cannot be ruled out, the composition is consistent with the particles originating as authigenic iron oxides which react with sulfide as they sink through the water column. The iron sulfide particles are richer in Cu (4,000 ppm) and Zn (6,000 ppm) than the iron oxides, suggesting that these elements are also concentrated as their insoluble sulfides. The coexistence of iron oxides and sulfides indicates that either the supply of sulfide is limiting or that some iron oxide particles are unreactive. 20 refs., 2 figs., 1 tab.

• OSTI ID: 6614790
• Journal Information: Limnology and Oceanography; (United States), Vol. 37:8; ISSN 0024-3590
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
IRON OXIDES
CHEMICAL REACTIONS
IRON SULFIDES
ORIGIN
PIXE ANALYSIS
LAKES
SULFUR CYCLE
PARTICLES
BACKSCATTERING
CALCIUM
DISTRIBUTION
EMISSION
FILTRATION
IRON
MANGANESE
PHOSPHORUS
POTASSIUM
SIZE
STOICHIOMETRY
SULFIDES
WATER
ALKALI METALS
ALKALINE EARTH METALS
CHALCOGENIDES
CHEMICAL ANALYSIS
ELEMENTS
HYDROGEN COMPOUNDS
IRON COMPOUNDS
METALS
NONDESTRUCTIVE ANALYSIS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
SCATTERING
SEPARATION PROCESSES
SULFUR COMPOUNDS
SURFACE WATERS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
X-RAY EMISSION ANALYSIS
540311* - Environment
Aquatic- Basic Studies- Radiometric Techniques- (1990-)