(Table 1, pages 779) Alpha track determination of growth rates of manganese nodules, Pacific Ocean


Analyses of the total alpha radioactivity distribution in 31 North Pacific manganese nodules yield an average growth rate of 6.8 ( 2) mm /m.y. Samples from a single box core show almost identical total activity vs. depth profiles, regardless of nodule size or shape. A characteristic feature of many nodules examined is an apparent change (steepening) in slope of the alpha activity profile between depths of 0.5-1.5 mm. This feature may reflect a fundamental feature of nodule growth, possibly mobility of 230Th or its daughters in a regular way, interrupted growth, or nodule turnover. Near-surface decreases in total alpha activity probably result from 226Ra loss.

Alpha particle tracks are detected photographically in a cellulose nitrate detector. Growth rates are determined from the ratio 230Th/231Pa excess.From 1983 until 1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions. At the time it was the most extended data compilation on ferromanganese deposits world wide. Initially published in a proprietary format incompatible with present day standards it was jointly decided by AWI and NOAA to transcribe this legacy data into PANGAEA. This transfer is augmented by a careful checking of the original sources when available and the encoding of ancillary information (sample description, method of analysis...) not present in the NOAA-MMS database.

Supplement to: MacDougall, J Douglas (1979): The distribution of total alpha radioactivity in selected manganese nodules from the North Pacific: implications for growth processes. In: Bischoff, J.L., Piper, D.Z. (Eds.), Marine Geology and Oceanography of the Pacific Manganese Nodule Province, Marine Science. Plenum Publishing Corporation, New York, U.S.A., 775-790

DOI https://doi.org/10.1594/PANGAEA.881562
Related Identifier IsSupplementTo https://doi.org/10.1007/978-1-4684-3518-4_25
Related Identifier IsDerivedFrom https://doi.org/10.7289/V52Z13FT
Related Identifier IsDocumentedBy https://doi.org/10.7289/V53X84KN
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.881562
Creator MacDougall, J Douglas
Publisher PANGAEA
Publication Year 1979
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 164 data points
Discipline Earth System Research
Spatial Coverage (-107.800W, -4.233S, 173.765E, 40.340N); Pacific Ocean; DOMES Site C, Pacific Ocean
Temporal Coverage Begin 1950-08-05T00:00:00Z
Temporal Coverage End 1976-08-27T00:00:00Z