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Carbon isotope evidence for a magmatic origin for Archaean gold-quartz vein ore depositsSediments from three sites in the Santa Barbara Basin were examined with a 160X power light microscope and TEM equipment to characterize the magnetostatic bacteria (MB) in the samples. Both the free magnetite and the crystals in the MB in the samples had lengths from 40-60 nm in length and increased in size from one end to the next. An intact magnetosome was also observed. Scanning the sediments with saturation isothermal remanent magnetization (SIRM) and altering field demagnetization techniques using a SQUID magnetometer yielded coercivity spectra which showed that the primary remanence carrier in the sediments was single domain magnetite. Although it is expected that the predominance of the bacterial magnetite component will decrease with depth in the open ocean basin, single-domain bacteria as old as 50 Myr have been observed in oceanic sediments.
Document ID
19860061203
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Burrows, D. R.
(California Institute of Technology Jet Propulsion Laboratory, Pasadena, United States)
Wood, P. C.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Spooner, E. T. C.
(California Institute of Technology Pasadena, United States)
Date Acquired
August 12, 2013
Publication Date
June 26, 1986
Publication Information
Publication: Nature
Volume: 321
ISSN: 0028-0836
Subject Category
Geophysics
Accession Number
86A45941
Funding Number(s)
CONTRACT_GRANT: NSF EAR-83-51370
CONTRACT_GRANT: NSF EAR-84-07655
Distribution Limits
Public
Copyright
Other

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