Iron Formations as Palaeoenvironmental Archives

An concise overview of iron formations as archives of diverse palaeoenvironmental information on early Earth history.

Kaarel Mänd (Author), Leslie J. Robbins (Author), Noah J. Planavsky (Author), Andrey Bekker (Author), Kurt O. Konhauser (Author)

9781108995290, Cambridge University Press

Paperback / softback, published 20 January 2022

75 pages
22.9 x 15.2 x 0.3 cm, 0.073 kg

Ancient iron formations - iron and silica-rich chemical sedimentary rocks that formed throughout the Precambrian eons - provide a significant part of the evidence for the modern scientific understanding of palaeoenvironmental conditions in Archaean (4.0–2.5 billion years ago) and Proterozoic (2.5–0.539 billion years ago) times. Despite controversies regarding their formation mechanisms, iron formations are a testament to the influence of the Precambrian biosphere on early ocean chemistry. As many iron formations are pure chemical sediments that reflect the composition of the waters from which they precipitated, they can also serve as nuanced geochemical archives for the study of ancient marine temperatures, redox states, and elemental cycling, if proper care is taken to understand their sedimentological context.

1. Introduction
2. Iron Formations as Geochemical Proxies
3. Palaeotemperature
4. Nutrient Availability
5. Palaeoredox
6. Bulk vs. In-situ Analysis
7. Comparison of IF, Shale, and Carbonate Mo Records: A Case Study
8. Outlook.

Subject Areas: Meteorology & climatology [RBP], Oceanography [seas RBKC], Geochemistry [RBGK], Earth sciences [RB]