The microbial carbonate factory of Hamelin Pool, Shark Bay, Western Australia

Hamelin Pool, located in Shark Bay, Western Australia, functions as a modern microbial carbonate factory, offering critical insights into sedimentary deposits of microbial origin found in the geologic record. This study reveals that while the pool is renowned for its living marine stromatolites, erosion and degradation of weakly lithified microbial mats significantly contribute to the production and accumulation of sand-sized micritic grains. Comprehensive mapping shows that over 40 km² of upper intertidal shoreline and 20 km² of subtidal pavements are colonized by these mats, which erode to form irregular peloidal grains and platey micritic intraclasts. Together, these sediments make up nearly 26% of the total sediment in the pool, plausibly producing around 24,000 metric tons annually. This dual process of construction by lithifying microbial mats and erosion of weakly lithified mats provides a modern analog for ancient microbialite-micritic sediment facies associations.

Suosaari, E. P., Reid, R. P., Mercadier, C., Vitek, B. E., Oehlert, A. M., Stolz, J. F., Giusfredi, P. E., & Eberli, G. P. (2022). The microbial carbonate factory of Hamelin Pool, Shark Bay, Western Australia. Scientific Reports, 12(1). https://doi.org/10.1038/s41598-022-16651-z