Abstract

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.

Details

Title
Submarine metalliferous carbonate mounds in the Cambrian of the Baltoscandian Basin induced by vent networks and water column stratification
Author
Javier, Álvaro J 1 ; Holmer, Lars E 2 ; Shen Yanan 3 ; Popov, Leonid E 4 ; Ghobadi Pour Mansoureh 5 ; Zhang Zhifei 6 ; Zhang, Zhiliang 6 ; Ahlberg Per 7 ; Bauert Heikki 8 ; González-Acebrón, Laura 9 

 Instituto de Geociencias (CSIC-UCM), Madrid, Spain (GRID:grid.473617.0) 
 Uppsala University, Department of Earth Sciences, Palaeobiology, Uppsala, Sweden (GRID:grid.8993.b) (ISNI:0000 0004 1936 9457); Northwest University, State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Xi’an, China (GRID:grid.412262.1) (ISNI:0000 0004 1761 5538) 
 University of Science and Technology of China, School of Earth and Space Sciences, Hefei, China (GRID:grid.59053.3a) (ISNI:0000000121679639) 
 National Museum of Wales, Department of Natural Sciences, Cardiff, UK (GRID:grid.422296.9) (ISNI:0000 0001 2293 9551) 
 National Museum of Wales, Department of Natural Sciences, Cardiff, UK (GRID:grid.422296.9) (ISNI:0000 0001 2293 9551); Golestan University, Department of Geology, Faculty of Sciences, Gorgan, Iran (GRID:grid.440784.b) (ISNI:0000 0004 0440 6526) 
 Northwest University, State Key Laboratory of Continental Dynamics, Shaanxi Key Laboratory of Early Life and Environments, Department of Geology, Xi’an, China (GRID:grid.412262.1) (ISNI:0000 0004 1761 5538) 
 Lund University, Department of Geology, Lund, Sweden (GRID:grid.4514.4) (ISNI:0000 0001 0930 2361) 
 Geological Survey of Estonia, Tallinn, Estonia (GRID:grid.434380.8) (ISNI:0000 0001 0706 1912) 
 Universidad Complutense, Madrid, Spain (GRID:grid.4795.f) (ISNI:0000 0001 2157 7667) 
Publication year
2022
Publication date
2022
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2666720790
Copyright
© The Author(s) 2022. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.