Fig. 6: Environmental model illustrating mechanisms of Hg-mobility and isotope fractionation in the Central European Basin.

This conceptual model illustrates the major terrestrial disturbance forces in the marginal fluvio-lacustrine environment and the resulting depositional changes in the shallow marine basin. Scenario a shows periods of explosive eruptions of the Central Atlantic Magmatic Province (CAMP) with high Hg-input, associated with the Spelae carbon isotope excursion (CIE) and Triassic–Jurassic transition. The intervals during the Hettangian b are dominated by orbital variation. Here, the scenarios of eccentricity minima (left) and maxima (right) show the two extremes in orbital forcing and disturbance¹³. The white triangle (spore) indicates the conditions for the formation of spore malformations. Blue arrows indicate environmental Hg pathways/processes that result in negative shifts in mass-independent fractionation (Δ¹⁹⁹Hg), while red arrows indicate processes resulting in positive shifts.