TY - JOUR

T1 - Stromatolites as geochemical archives to reconstruct microbial habitats through deep time

T2 - Potential and pitfalls of novel radiogenic and stable isotope systems

AU - Hohl, Simon V.

AU - Viehmann, Sebastian

N1 - Funding information: We would like to acknowledge the Research Fund for International Young Scientists given to S.V·H by the National Science Foundation of China (grant no. 41950410566 ). We also kindly acknowledge the editorial handling of Alessandra Negri and the constructive comments of two anonymous reviewers. This manuscript is related to the SPP1833 ‘Building a habitable Earth’ and significantly improved from discussions during related fieldwork and meetings.

PY - 2021/7

Y1 - 2021/7

N2 - Understanding the origin and evolution of life on Earth and potentially other planets in our solar system is of fundamental interest for humanity. For the longest time in Earth's history, life evolved in microbial communities. It is, however, still incompletely understood how, when and where such habitable environments formed and how microbial communities adopted to the drastic changes of the atmosphere-hydrosphere-lithosphere systems through deep time. Stromatolites, i.e., lithified microbial mats that occur in sedimentary successions from at least 3.4 billion years ago until today, hold the geochemical key to our understanding of the evolution of microbial life on Earth and may also provide a blueprint for planetary studies. This review targets the potential and pitfalls of emerging and established isotope applications to stromatolites based on improved and newly developed analytical and technical capabilities in the last decades. We provide a comprehensive overview of present data and the interpretation of applications of radiogenic (U–Pb, Rb–Sr, Sm–Nd) and stable (O, C-N-S, Fe, Mo, Cr, U, Cd) isotope systems in stromatolites. Although the behaviour and fractionation processes of different isotope systems in stromatolites and microbial mats are incompletely understood, the different isotope proxies are used to better understand and reconstruct microbial habitats in stromatolite-forming environments through deep time. Primarily, radiogenic isotopes are used to directly date stromatolites and determine the source of elements in ancient stromatolite environments, while stable isotopes are used to understand redox conditions, metal availability, and (biogenic) metal cycling processes in microbial habitats. We provide deep insights into each isotope application in stromatolites and show their unique potential and future perspectives to bridge the gap between geochemistry and microbiology and to better understand the evolution of microbial life on Earth and beyond.

AB - Understanding the origin and evolution of life on Earth and potentially other planets in our solar system is of fundamental interest for humanity. For the longest time in Earth's history, life evolved in microbial communities. It is, however, still incompletely understood how, when and where such habitable environments formed and how microbial communities adopted to the drastic changes of the atmosphere-hydrosphere-lithosphere systems through deep time. Stromatolites, i.e., lithified microbial mats that occur in sedimentary successions from at least 3.4 billion years ago until today, hold the geochemical key to our understanding of the evolution of microbial life on Earth and may also provide a blueprint for planetary studies. This review targets the potential and pitfalls of emerging and established isotope applications to stromatolites based on improved and newly developed analytical and technical capabilities in the last decades. We provide a comprehensive overview of present data and the interpretation of applications of radiogenic (U–Pb, Rb–Sr, Sm–Nd) and stable (O, C-N-S, Fe, Mo, Cr, U, Cd) isotope systems in stromatolites. Although the behaviour and fractionation processes of different isotope systems in stromatolites and microbial mats are incompletely understood, the different isotope proxies are used to better understand and reconstruct microbial habitats in stromatolite-forming environments through deep time. Primarily, radiogenic isotopes are used to directly date stromatolites and determine the source of elements in ancient stromatolite environments, while stable isotopes are used to understand redox conditions, metal availability, and (biogenic) metal cycling processes in microbial habitats. We provide deep insights into each isotope application in stromatolites and show their unique potential and future perspectives to bridge the gap between geochemistry and microbiology and to better understand the evolution of microbial life on Earth and beyond.

KW - Early life

KW - Microbial habitats

KW - Radiogenic isotopes

KW - Stable isotopes

KW - Stromatolites

UR - http://www.scopus.com/inward/record.url?scp=85110520720&partnerID=8YFLogxK

U2 - 10.1016/j.earscirev.2021.103683

DO - 10.1016/j.earscirev.2021.103683

M3 - Article

AN - SCOPUS:85110520720

VL - 218

JO - Earth-Science Reviews

JF - Earth-Science Reviews

SN - 0012-8252

M1 - 103683

ER -