thumb|Fossilized stromatolite in Strelley Pool [[chert, about 3.4 billion years old, from Pilbara Craton, Western Australia]] thumb|Modern stromatolites in Shark Bay, Western Australia|Shark Bay, Western Australia
thumb|Fossilized stromatolite in Strelley Pool [[chert, about 3.4 billion years old, from Pilbara Craton, Western Australia]] thumb|Modern stromatolites in Shark Bay, Western Australia|Shark Bay, Western Australia
Stromatolites ( ) or stromatoliths () are layered sedimentary formations (microbialite) that are created mainly by photosynthetic microorganisms such as cyanobacteria, sulfate-reducing bacteria, and Pseudomonadota (formerly proteobacteria). These microorganisms produce adhesive compounds that cement sand and other rocky materials to form mineral "microbial mats". In turn, these mats build up layer by layer, growing gradually over time.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).