Ammonium silicates associated with sedimentary exhalative ore deposits: A geochemical exploration tool

Lynda Williams, H. Zantop, R. C. Reynolds

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The fixed-ammonium (NH4 +) concentration in sediments hosting sedimentary exhalative Zn-Pb-(Ag) sulfide deposits was examined at the Howards Pass, Clear Lake, Tom and Jason deposits in the Selwyn Basin, Yukon Territory, Canada. A few samples from the McArthur River deposit, Australia, were examined for comparison. Infrared spectrophotometry shows that NH4 + concentrations in alkali-bearing mineral phases increase near ore bodies not diluted by the influx of abundant detrital material. In whole-rock samples from the Selwyn Basin, NH4 + concentrations reach as high as 2000 ppm above ore, against a background of approximately 467 ± 70 ppm. In McArthur River's Emu Basin, the concentration of NH4 + in two samples located adjacent to sulfides reaches over 2000 ppm whereas no NH4 + was detected in any other samples taken from one core through the deposit. All samples for this study were taken from well below the weathered zone. X-ray diffraction of clay minerals does not indicate NH4 + substitution for K+ in interlayer sites. Instead, a comparison of NH4 + concentrations with X-ray diffraction estimates of major mineral constituents of the samples suggests that NH4 + substitutes for K+ and Na+ in feldspars. The substitution is highest in the stratigraphic hanging wall at both the Howards Pass and Clear Lake deposits. At Clear Lake, high NH4 + values (up to 1800 ppm) are found near stringer mineralization, presumably where the venting of hydrothermal fluids occurred. The Tom and Jason deposits contain low or background NH4 + concentrations throughout the stratigraphic section, probably as a result of detrital dilution of the host sediments from slumping within a local graben coincident with mineralization. High concentrations of ammonia (NH3) may be incorporated in hydrothermal solutions by breakdown of organic matter in the sedimentary pile. As hot, mineralizing fluids rise into a starved, stagnant basin of low pH and reducing conditions, NH4 + would become the dominant nitrogen species at low temperature and may substitute for K+ or Na+ in authigenic minerals.

Original languageEnglish (US)
Pages (from-to)125-141
Number of pages17
JournalJournal of Geochemical Exploration
Volume27
Issue number1-2
DOIs
StatePublished - 1987
Externally publishedYes

Fingerprint

Ore deposits
Silicates
Ammonium Compounds
ore deposit
ammonium
Deposits
silicate
substitution
X-ray diffraction
sulfide
basin
mineralization
Minerals
Lakes
authigenic mineral
slumping
venting
lake
ore body
Sulfides

ASJC Scopus subject areas

  • Economic Geology
  • Geochemistry and Petrology

Cite this

Ammonium silicates associated with sedimentary exhalative ore deposits : A geochemical exploration tool. / Williams, Lynda; Zantop, H.; Reynolds, R. C.

In: Journal of Geochemical Exploration, Vol. 27, No. 1-2, 1987, p. 125-141.

Research output: Contribution to journalArticle

@article{8bd5c3e03eba41b880af52fb74903ec0,
title = "Ammonium silicates associated with sedimentary exhalative ore deposits: A geochemical exploration tool",
abstract = "The fixed-ammonium (NH4 +) concentration in sediments hosting sedimentary exhalative Zn-Pb-(Ag) sulfide deposits was examined at the Howards Pass, Clear Lake, Tom and Jason deposits in the Selwyn Basin, Yukon Territory, Canada. A few samples from the McArthur River deposit, Australia, were examined for comparison. Infrared spectrophotometry shows that NH4 + concentrations in alkali-bearing mineral phases increase near ore bodies not diluted by the influx of abundant detrital material. In whole-rock samples from the Selwyn Basin, NH4 + concentrations reach as high as 2000 ppm above ore, against a background of approximately 467 ± 70 ppm. In McArthur River's Emu Basin, the concentration of NH4 + in two samples located adjacent to sulfides reaches over 2000 ppm whereas no NH4 + was detected in any other samples taken from one core through the deposit. All samples for this study were taken from well below the weathered zone. X-ray diffraction of clay minerals does not indicate NH4 + substitution for K+ in interlayer sites. Instead, a comparison of NH4 + concentrations with X-ray diffraction estimates of major mineral constituents of the samples suggests that NH4 + substitutes for K+ and Na+ in feldspars. The substitution is highest in the stratigraphic hanging wall at both the Howards Pass and Clear Lake deposits. At Clear Lake, high NH4 + values (up to 1800 ppm) are found near stringer mineralization, presumably where the venting of hydrothermal fluids occurred. The Tom and Jason deposits contain low or background NH4 + concentrations throughout the stratigraphic section, probably as a result of detrital dilution of the host sediments from slumping within a local graben coincident with mineralization. High concentrations of ammonia (NH3) may be incorporated in hydrothermal solutions by breakdown of organic matter in the sedimentary pile. As hot, mineralizing fluids rise into a starved, stagnant basin of low pH and reducing conditions, NH4 + would become the dominant nitrogen species at low temperature and may substitute for K+ or Na+ in authigenic minerals.",
author = "Lynda Williams and H. Zantop and Reynolds, {R. C.}",
year = "1987",
doi = "10.1016/0375-6742(87)90008-2",
language = "English (US)",
volume = "27",
pages = "125--141",
journal = "Journal of Geochemical Exploration",
issn = "0375-6742",
publisher = "Elsevier",
number = "1-2",

}

TY - JOUR

T1 - Ammonium silicates associated with sedimentary exhalative ore deposits

T2 - A geochemical exploration tool

AU - Williams, Lynda

AU - Zantop, H.

AU - Reynolds, R. C.

PY - 1987

Y1 - 1987

N2 - The fixed-ammonium (NH4 +) concentration in sediments hosting sedimentary exhalative Zn-Pb-(Ag) sulfide deposits was examined at the Howards Pass, Clear Lake, Tom and Jason deposits in the Selwyn Basin, Yukon Territory, Canada. A few samples from the McArthur River deposit, Australia, were examined for comparison. Infrared spectrophotometry shows that NH4 + concentrations in alkali-bearing mineral phases increase near ore bodies not diluted by the influx of abundant detrital material. In whole-rock samples from the Selwyn Basin, NH4 + concentrations reach as high as 2000 ppm above ore, against a background of approximately 467 ± 70 ppm. In McArthur River's Emu Basin, the concentration of NH4 + in two samples located adjacent to sulfides reaches over 2000 ppm whereas no NH4 + was detected in any other samples taken from one core through the deposit. All samples for this study were taken from well below the weathered zone. X-ray diffraction of clay minerals does not indicate NH4 + substitution for K+ in interlayer sites. Instead, a comparison of NH4 + concentrations with X-ray diffraction estimates of major mineral constituents of the samples suggests that NH4 + substitutes for K+ and Na+ in feldspars. The substitution is highest in the stratigraphic hanging wall at both the Howards Pass and Clear Lake deposits. At Clear Lake, high NH4 + values (up to 1800 ppm) are found near stringer mineralization, presumably where the venting of hydrothermal fluids occurred. The Tom and Jason deposits contain low or background NH4 + concentrations throughout the stratigraphic section, probably as a result of detrital dilution of the host sediments from slumping within a local graben coincident with mineralization. High concentrations of ammonia (NH3) may be incorporated in hydrothermal solutions by breakdown of organic matter in the sedimentary pile. As hot, mineralizing fluids rise into a starved, stagnant basin of low pH and reducing conditions, NH4 + would become the dominant nitrogen species at low temperature and may substitute for K+ or Na+ in authigenic minerals.

AB - The fixed-ammonium (NH4 +) concentration in sediments hosting sedimentary exhalative Zn-Pb-(Ag) sulfide deposits was examined at the Howards Pass, Clear Lake, Tom and Jason deposits in the Selwyn Basin, Yukon Territory, Canada. A few samples from the McArthur River deposit, Australia, were examined for comparison. Infrared spectrophotometry shows that NH4 + concentrations in alkali-bearing mineral phases increase near ore bodies not diluted by the influx of abundant detrital material. In whole-rock samples from the Selwyn Basin, NH4 + concentrations reach as high as 2000 ppm above ore, against a background of approximately 467 ± 70 ppm. In McArthur River's Emu Basin, the concentration of NH4 + in two samples located adjacent to sulfides reaches over 2000 ppm whereas no NH4 + was detected in any other samples taken from one core through the deposit. All samples for this study were taken from well below the weathered zone. X-ray diffraction of clay minerals does not indicate NH4 + substitution for K+ in interlayer sites. Instead, a comparison of NH4 + concentrations with X-ray diffraction estimates of major mineral constituents of the samples suggests that NH4 + substitutes for K+ and Na+ in feldspars. The substitution is highest in the stratigraphic hanging wall at both the Howards Pass and Clear Lake deposits. At Clear Lake, high NH4 + values (up to 1800 ppm) are found near stringer mineralization, presumably where the venting of hydrothermal fluids occurred. The Tom and Jason deposits contain low or background NH4 + concentrations throughout the stratigraphic section, probably as a result of detrital dilution of the host sediments from slumping within a local graben coincident with mineralization. High concentrations of ammonia (NH3) may be incorporated in hydrothermal solutions by breakdown of organic matter in the sedimentary pile. As hot, mineralizing fluids rise into a starved, stagnant basin of low pH and reducing conditions, NH4 + would become the dominant nitrogen species at low temperature and may substitute for K+ or Na+ in authigenic minerals.

UR - http://www.scopus.com/inward/record.url?scp=0023523971&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0023523971&partnerID=8YFLogxK

U2 - 10.1016/0375-6742(87)90008-2

DO - 10.1016/0375-6742(87)90008-2

M3 - Article

AN - SCOPUS:0023523971

VL - 27

SP - 125

EP - 141

JO - Journal of Geochemical Exploration

JF - Journal of Geochemical Exploration

SN - 0375-6742

IS - 1-2

ER -