Publication Date:
2023-08-28
Description:
Initial data on the hydrogen-isotopic compositions in hydrous Mn minerals from various occurrences fall in a wide range from -298 to -84 per mil, relative to SMOW. DeltaD-values of todorokite and cryptomelane from Tertiary deposits show -89 and -150 per mil. 10 Angström-manganite and Delta-MnO2 from deep-sea nodules have relatively restricted DeltaD-values ranging from -96 to -84 per mil. The DeltaD-values for manganese bog ores from recent hot springs show almost -105 per mil. It is recognized that the isotopic values obtained for the deep-sea nodules and recent bog ores are slightly different ranged. Manganite and groutite are unique in their hydrogen-isotopic compositions, having the most depleted DeltaD-values ranging from -298 to -236 per mil. MnO(OH) minerals are more deuterium-depleted hydrous minerals than any other hydrothermal minerals from various ore deposits. Hydrogen-isotope fractionation factors between manganite and water were experimentally determined to be 0.7894, 0.7958 and 0.8078 at 150°, 200° and 250°C, respectively. the present experimental results indicate that if manganites were formed at temperatures below 250°C, under isotopic equilibrium conditions, most of the manganite mineralization in the Tertiary manganese deposits must have precipitated from meteoric hydrothermal solutions.
Keywords:
Core; CORE; Deposit type; DEPTH, sediment/rock; Dredge, box; DRG_B; Event label; FFGR; Free-fall grab; GH77-1; GH77-1-D212; GH77-1-FG40-1; GH77-1-G384; Hakuho-Maru; Hakurei-Maru (1974); Identification; Isotope ratio mass spectrometry; KH-73-4; KH73-4-2; NOAA and MMS Marine Minerals Geochemical Database; NOAA-MMS; O70; Ocean 70 grab; Pacific Ocean; δ Deuterium
Type:
Dataset
Format:
text/tab-separated-values, 12 data points
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