Authigenic carbonate of ODP SIte 104-643 ...
Different generations of complex authigenic carbonates formed in siliceous muds (lithologic Unit IV) and hemipelagic clays (lithologic Unit V) of ODP Site 643, Leg 104 Norwegian Sea. The dominant phase in Unit IV is an early diagenetic Mn, Fe-calcite with a strong negative d13C ( -14 to -16 per mil)...
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| Format: | Article in Journal/Newspaper |
| Language: | English |
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PANGAEA
1989
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| Online Access: | https://dx.doi.org/10.1594/pangaea.742922 https://doi.pangaea.de/10.1594/PANGAEA.742922 |
| Summary: | Different generations of complex authigenic carbonates formed in siliceous muds (lithologic Unit IV) and hemipelagic clays (lithologic Unit V) of ODP Site 643, Leg 104 Norwegian Sea. The dominant phase in Unit IV is an early diagenetic Mn, Fe-calcite with a strong negative d13C ( -14 to -16 per mil) signature, and slightly negative d180 values. The strong negative d13C results from extensive incorporation of 12C-enriched CO2 derived from bacterial degradation of marine organic matter into early Mn, Fe - calcite cements. Concomitant framboidal pyrite precipitation and abundant SEM microtextures showing excellent preservation of delicate structures of fragile diatom valves by outpourings with early Mn-calcites strongly support their shallow burial formation before the onset of compaction. Later generations of authigenic mineralizations in lithologic Unit IV include minor amounts of a second generation of calcite with platy crystals, possibly precipitated along with opal-A dissolution, and finally opal-CT ... : Supplement to: Henrich, Rüdiger (1989): Diagenetic environments of authigenic carbonates and opal-CT crystallization in lower Miocene to upper Oligocene deposits of the Norwegian Sea (ODP Site 643, Leg 104). In: Eldholm, O; Thiede, J; Taylor, E; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 104, 233-247 ... |
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