Redox conditions across the Upper Cambrian in Western Newfoundland, Canada ...
The lower part of the Martin Point section (~ 110 m - rhythmites) spans the uppermost Shallow Bay and lowermost Green Point formations (uppermost Franconian‒ lowermost Trempealeauan) of the Cow Head Group (western Newfoundland, Canada). It records two post-SPICE events (SPICE – Steptoean Positive Ca...
| Main Author: | |
|---|---|
| Format: | Text |
| Language: | English |
| Published: |
Memorial University of Newfoundland
2023
|
| Subjects: | |
| Online Access: | https://dx.doi.org/10.48336/wtg6-0h27 https://research.library.mun.ca/15986/ |
| Summary: | The lower part of the Martin Point section (~ 110 m - rhythmites) spans the uppermost Shallow Bay and lowermost Green Point formations (uppermost Franconian‒ lowermost Trempealeauan) of the Cow Head Group (western Newfoundland, Canada). It records two post-SPICE events (SPICE – Steptoean Positive Carbon Isotope Excursion) marked by negative δ¹³Ccarb excursions (NL1 and NL2) that were also documented in South China. The petrographic and chemical screening of the investigated carbonate samples proves the preservation of at least near-primary geochemical signatures. The proxies of weathering (e.g., Mn, Fe, Al, and ΣREE), bioproductivity (e.g., δ¹³Corg, TOC, P, Ni, Zn, and Cu), and paleoredox (e.g., Cr, Th/U, Ce/Ce*) have been utilized to reconstruct the paleoenvironmental conditions during the post-SPICE events. The TOC, P, Ni, Cu, Cr, ΣREE, Mn, Fe, and U enrichment-factor profiles exhibit a positive pulse at the base of NL2 (upper negative δ¹³Ccarb excursion), followed by a drop. This might have resulted from ... |
|---|