Microbially mediated intracellular barite mineralization: evidence from an early Ediacaran microfossil in the Doushantuo Formation of South China

Optical microscopy observations reveal that coccoidal microfossils appear dark brown or opaque due to the absorption of visible light by the organic matter. These microfossils typically form clusters, with individual cells arranged in dyads, triads, tetrads, or octads. The cells measure approximately 7.5 to 20.0 μm in diameter (mean = 13.1 μm, standard deviation = 2.9 μm, n = 145) and possess a distinct cell wall approximately 1 to 2μm thick. These morphological features enable comparison with <i>Archaeophycus yunnanensis</i>.