Redox conditions across the Upper Cambrian in Western Newfoundland, Canada ...

• Main Author: Okafor, Miracle-Mary Chisom
• Format: Text
• Language: English
• Published: Memorial University of Newfoundland 2023
• Subjects: Canada; Cow Head; Green Point; Martin Point; Shallow Bay; Newfoundland
• Online Access: https://dx.doi.org/10.48336/wtg6-0h27; https://research.library.mun.ca/15986/

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 ...