Hydrogenous manganese nodules form on the ocean floor by slow authigenic precipitation (1-6 mm/Ma) of the oxyhydroxides of manganese and iron that continuously scavenge trace elements from the marine environment. Consequently, these nodules represent independent marine deposits useful for the study of the chemical signatures of the paleomarine environments. The results presented are a continuation of a study of the Zetes-3D nodule from the Pacific Ocean. It is a large (24x17x10 cm) hydrogenous nodule whose slow growth rate of 1.3 mm/Ma was detremined using 10Be techniques. A positive cerium anomaly is observed throughout the nodule and its Ir content indicates a sharp spike at 54-62 Ma in fair agreement with the K-T event.
Iridium analysis method described in: J.B. Cumming, P.P. Parekh, A.V. Murali, A novel approach to the determination of iridium via Ge-coincidence/NaI(Tl)-anticoincidence gamma-ray spectrometry, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Volume 265, Issue 3, 1988, Pages 468-474, ISSN 0168-9002, doi:10.1016/S0168-9002(98)90015-8.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1989 NOAA-NCEI compiled the NOAA-MMS Marine Minerals Geochemical Database from journal articles, technical reports and unpublished sources from other institutions.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: Murali, A V; Blanchard, D P; Somayajulu, Bammidipati L K; Parekh, Payal (1991): K-T Boundary Signatures in the Manganese Nodule Zetes-3D. Abstracts of the Lunar and Planetary Science Conference, Lunar and Planetary Science Institute, Houston, Texas, 22, 939-940
