RT Journal Article
T1 Submarine metalliferous carbonate mounds in the Cambrian of the Baltoscandian Basin induced by vent networks and water column stratification
A1 Álvaro, J.J.
A1 Holmer, Lars E.
A1 Shen, Yanan
A1 Popov, Leonid E.
A1 Pour, Mansoureh Ghobadi
A1 Zhang, Zhifei
A1 Zhang, Zhiliang
A1 Ahlberg, Per
A1 Bauert, Heikki
A1 González Acebrón, Laura
AB Two massive precipitation events of polymetallic ore deposits, encrusted by a mixture of authigenic carbonates, are documented from the Cambrian of the semi-enclosed Baltoscandian Basin. δ34S (‒9.33 to ‒2.08‰) and δ33S (‒4.75 to ‒1.06‰) values from the basal sulphide breccias, sourced from contemporaneous Pb–Zn–Fe-bearing vein stockworks, reflect sulphide derived from both microbial and abiotic sulphate reduction. Submarine metalliferous deposits were triggered by non-buoyant hydrothermal plumes: plumes of buoyant fluid were trapped by water column stratification because their buoyancy with respect to the environment reversed, fluids became heavier than their surroundings and gravitational forces brought them to a halt, spreading out laterally from originating vents and resulting in the lateral dispersion of effluents and sulphide particle settling. Subsequently, polymetallic exhalites were sealed by carbonate crusts displaying three generations of ikaite-to-aragonite palisade crystals, now recrystallized to calcite and subsidiary vaterite. Th of fluid inclusions in early calcite crystals, ranging from 65 to 78 ºC, provide minimum entrapment temperatures for carbonate precipitation and early recrystallization. δ13Ccarb (‒1.1 to + 1.6‰) and δ18Ocarb (‒7.6 to ‒6.5‰) values are higher than those preserved in contemporaneous glendonite concretions (‒8.5 to ‒4.7‰ and ‒12.4 to ‒9.1‰, respectively) embedded in kerogenous shales, the latter related to thermal degradation of organic matter. Hydrothermal discharges graded from highly reduced, acidic, metalliferous, and hot (~ 150 ºC) to slightly alkaline, calcium-rich and warm (< 100 ºC), controlling the precipitation of authigenic carbonates.
PB Nature publishing group
SN 2045-2322
YR 2022
FD 2022
LK https://hdl.handle.net/20.500.14352/72973
UL https://hdl.handle.net/20.500.14352/72973
LA eng
NO Swedish Research Council
NO National Natural Science Foundation of China
DS Docta Complutense
RD 10 abr 2025