Journal Article

A lithium-isotope perspective on the evolution of carbon and silicon cycles

Hood, Ashleigh v. S., Dellinger, Mathieu, Bellefroid, Eric J., Higgins, John A., Isson, Terry T., Pogge von Strandmann, Philip A. E., West, A. Joshua, Wallace, Malcolm W., Planavsky, Noah J., Ossa, Frantz Ossa, Wang, Chunjiang, Murphy, Jack G., Jones, David S., Katchinoff, Joachim A. R., Macdonald, Francis A., Asael, Dan, Kalderon-Asael, Boriana, Hofmann, Axel

2021

Overview

The evolution of the global carbon and silicon cycles is thought to have contributed to the long-term stability of Earth’s climate 1 – 3 . Many questions remain, however, regarding the feedback mechanisms at play, and there are limited quantitative constraints on the sources and sinks of these elements in Earth’s surface environments 4 – 12 . Here we argue that the lithium-isotope record can be used to track the processes controlling the long-term carbon and silicon cycles. By analysing more than 600 shallow-water marine carbonate samples from more than 100 stratigraphic units, we construct a new carbonate-based lithium-isotope record spanning the past 3 billion years. The data suggest an increase in the carbonate lithium-isotope values over time, which we propose was driven by long-term changes in the lithium-isotopic conditions of sea water, rather than by changes in the sedimentary alterations of older samples. Using a mass-balance modelling approach, we propose that the observed trend in lithium-isotope values reflects a transition from Precambrian carbon and silicon cycles to those characteristic of the modern. We speculate that this transition was linked to a gradual shift to a biologically controlled marine silicon cycle and the evolutionary radiation of land plants 13 , 14 . Analysis of shallow-water marine carbonate samples from 101 stratigraphic units allows construction of a record of lithium isotopes from the past 3 billion years, tracking the evolution of the global carbon and silicon cycles.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 704/106/413 / 704/47/4113 / Adaptive radiation / Aquatic Organisms / Archives & records / Carbon / Carbon - analysis / Carbon - metabolism / Carbon Cycle / Carbon cycle (Biogeochemistry) / Carbon dioxide / Carbonates / Chemical analysis / Chemical properties / Clay / Earth surface / Evolution / Geologic Sediments - chemistry / Humanities and Social Sciences / Isotopes / Isotopes - analysis / Lithium / Lithium - analysis / Marine biology / Mass balance / Mineralogy / multidisciplinary / Natural history / Plants / Precambrian / Radiation / Science / Science (multidisciplinary) / Seawater / Seawater - chemistry / Sediments / Shallow water / Silicon / Silicon - analysis / Silicon - metabolism / Silicon cycle / Stratigraphy / Trends / Variance analysis / Water analysis