Elemental and isotopic compositions of trench-slope black shales, Bohemian Massif, with implications for oceanic and atmospheric oxygenation in early Cambrian

Multi-stage metal enrichment and formation of gold mineralization in black shales: the role of high heat flow in a rift setting

“…Pyrite separates were prepared by a combination of crushing, hand picking, and leaching, resulting in > 95% purity of the separates. Sulfur isotopic compositions of pyrite as well as those of bulk rocks were determined at the Laboratory for Stable and Radiogenic Isotopes at the Faculty of Science, Charles University, using methods detailed in Pašava et al (2021).…”

“…Interestingly, basalt blocks are absent and black shales are rare in Belt I unlike the other mélange belts. Elsewhere, the black shales have been interpreted as deposits of trenchslope basins during periods of limited siliciclastic supply (Kurzweil et al 2015;Pašava et al 2021). The published U-Pb detrital zircon geochronology constrains the age of the chert-graywacke unit to ca.…”

Seawater silica cycling and chert formation at the Neoproterozoic–Cambrian transition: Insights from δ30Si and Ge/Si systematics of hydrothermal cherts from the Bohemian Massif

“…1). The Belts 1-3 consist of predominant graywacke and shale with subordinate black shale (e.g., Pašava et al, 2021), chert (Belt 1 and 2; Ackerman et al, 2023) and limestone (Ackerman et al, 2022), and abundant basaltic blocks of MORB and OIB composition (Ackerman et al, 2019;Pin and Waldhausrová, 2007). In contrast, the Belt II-III section almost devoid of basaltic rocks is represented by rather uniform sedimentary successions dominated by graywacke-shale, sometimes accompanied by black shales (Belt II; e.g., Pašava, 2000); the graywacke-chert Belt I was interpreted as an olistostrome formed at the outer trench slope of the subducted slab (Hajná et al, 2019).…”