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Calcified Biofilms from Cambrian Oolitic Limestones in China
Author(s) -
Wei LIU,
Xingliang ZHANG
Publication year - 2015
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.12395
Subject(s) - micrite , ooid , geology , diagenesis , petrography , biofilm , sedimentary depositional environment , paleontology , mineralogy , facies , structural basin , bacteria
Calcified biofilms are preserved as thin micritic coatings in the Cambrian oolitic limestone of two sections in North and South China. Standard petrographic examination revealed that the biofilms were developed during the early diagenetic stage immediately after the freshly deposited ooids, proceeding in the continuous sequence of depositional processes. The biofilm outlines are highly irregular, with steep sides, tower‐like structures and overhanging projections; the internal fabric of the biofilms is composed of roughly laminated micrite aggregates with channel‐like structures. Biofilms exhibit a strong fluorescent reaction. Detailed SEM examination suggests that the biofilms are biotically dominated by cyanobacteria. Our study demonstrates that microbial colonies, such as biofilms, can develop on ooid cortices and influence the formation and microstructures of those ooids.