Late Precambrian-Cambrian field strength oxygenation and animal evolution. Top: Tonian to Cambrian field strength (see Fig. 6) with trend lines from Bono et al. [18] and Zhou et al. [77]. Red symbols are Thellier single-crystal time-averaged data; ultra-low values define an ultra-low time-averaged field interval (UL-TAFI). Also shown are results from whole-rock data from Shcherbakova et al. [89], Thallner et al. [90,92,93] and Lloyd et al. [91] with the following symbols: open circles are results from non-Thellier methods and their sizes are weighted by the number of cooling units; green microwave method; purple Shaw method; black Wilson method; brown open circles Thellier thermal results. Middle: oxygenation from selenium isotopes after Pogge von Strandmann et al. [143], sliding window and 1|$\sigma$| uncertainty from Huang et al. [78]. Bottom: animal evolution after Zhuravlev and Wood [121], Darroch et al. [122], Muscente et al. [123] and Wood et al. [124]. The Shuram isotopic excursion is also shown for reference with ages from Rooney et al. [172]. Figure modified from Huang et al. [78], licensed under CC BY 4.0.