Fig. 1: Summary of relevant geographical and stratigraphic data.
a Late Cambrian (494 Ma) global palaeogeography85. b Location map showing the original distribution of the Alum Shale Formation in southern Scandinavia and the location of wells referred to (modified from ref. 30). c Biozonation, lithology and cyclostratigraphy of the Furongian interval including strata below and above in the Albjära-1 core, as well as representative core photos of the shale, a limestone lens and a bedding surface covered by fossils. The base of Stage 10 remains to be formally defined (see text for remarks), only the base defined by the FAD of L. americanus is plotted here. The 405-kyr eccentricity cycles in four subsets 0–18, 18–41, 41–55 and 55–74 m were extracted using Taner filters with centres (cut-offs) of 1.9 (1.3–3.3) cycles/m, 2.4 (1.5–4.2) cycles/m, 2.3 (1.0–5.0) cycles/m, and 1.8 (1.1–3.6) cycles/m, respectively. Adjusted depth was obtained by measuring from the Alum Shale Formation top downward after reducing the original limestone thickness to 20%. Lamination cycles are closely tracked by Al concentration variations (the 178.52–181.21 m interval is shown as an example).
