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Magnesium silicate chimneys at the Strytan hydrothermal field, Iceland, as analogues for prebiotic chemistry at alkaline submarine hydrothermal vents on the early Earth

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Peer-reviewed

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Authors

Gutiérrez-Ariza, Carlos 
Barge, Laura M 
Ding, Yang 
Cardoso, Silvana SS 
McGlynn, Shawn Erin 

Abstract

jats:titleAbstract</jats:title>jats:pThe Strytan Hydrothermal Field (SHF) in basaltic terrain in Iceland is one of the extant alkaline submarine hydrothermal vent systems favoured as analogues for where life on Earth may have begun. To test this hypothesis we analyse the composition, structure, and mineralogy of samples from hydrothermal chimneys generated at the SHF. We find that the chimney precipitates are composed of Mg-silicates including clays of the saponite-stevensite group (high Mg and Si, low Fe and Al), Ca-carbonates and Ca-sulfates. The chimneys comprise permeable structures with pores sizes down to 1 µm or less. Their complex interiors as observed with SEM (Scanning Electron Microscopy) and X-ray CT (computed tomography scanning), exhibit high internal surface areas. EDX (energy-dispersive X-ray spectroscopy) analysis reveals an increase in the Mg/Si ratio toward the chimney exteriors. Chemical garden analogue experiments produce similar Mg–silicate chimneys with porous internal structures, indicating that injection-precipitation experiments can be high-fidelity analogues for natural hydrothermal chimneys at the SHF. We conclude that SHF chimneys could have facilitated prebiotic reactions comparable to those proposed for clays and silica gels at putative Hadean to Eoarchean alkaline vents. Analysis of the fluid dynamics shows that these chimneys are intermediate in growth rate compared to faster black smokers though slower than those at Lost City. The SHF is proposed as a prebiotic alkaline vent analogue for basaltic terrains on the early Earth.</jats:p>

Description

Acknowledgements: This research was supported in part by the ELSI Origins Network (EON), which was supported by a grant from the John Templeton Foundation. REP acknowledges NASA Habitable Worlds Program Grant Nos. 80NSSC20K0228 and 80NSSC24K0076. SEM acknowledges JSPS KAKENHI Grant No. 22K18278. LMB’s work was performed at the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA (80NM0018D004). This research was funded in part by Spanish FEDER/Junta de Andalucía‐Consejería de Economía y Conocimiento grant PY20_01389. We acknowledge the contribution of the COST Actions CA17120, Chemobrionics and CA21169, Dynalife, supported by European Cooperation in Science and Technology.


Funder: Consejo Superior de Investigaciones Cientificas (CSIC)

Keywords

37 Earth Sciences, 51 Physical Sciences, 5101 Astronomical Sciences, 3703 Geochemistry, 3705 Geology

Journal Title

Progress in Earth and Planetary Science

Conference Name

Journal ISSN

2197-4284
2197-4284

Volume Title

11

Publisher

Springer Science and Business Media LLC