Fig. 9: Conceptual model of arsenic enrichment mechanisms and preservation potential across microbialite architectures from Hamelin Pool.

Each column highlights a microbialite architecture in Hamelin Pool (see Fig. 1). In each row, the left panel illustrates the microbialite architecture, including the distribution and proportion of organic matter, micrite, and trapped-and-bound (T&B) allochems, while the right panel presents the arsenic concentrations associated with each of these fractions. The first row illustrates the conditions at the time of accretion, highlighting each microbialite architecture’s morphology, fabric, and accretion mechanisms, along with their associated arsenic enrichment patterns. The second row shows arsenic enrichment patterns, including the proportions and concentrations of arsenic-bearing fractions. Black arrows are enrichment factors (EF) that describe arsenic transfer from seawater to the different fractions. Red arrows represent the transfer of arsenic from organic matter to micrite. The third row depicts the expected preservation potential of arsenic enrichment patterns in the geological record.