Biofilm-related calcification, sediment trapping and constructive micrite envelopes: a criterion for the recognition of ancient grass-bed environments?
Article first published online: 5 JAN 2002
Volume 46, Issue 1, pages 33–45, February 1999
How to Cite
Perry, C. T. (1999), Biofilm-related calcification, sediment trapping and constructive micrite envelopes: a criterion for the recognition of ancient grass-bed environments?. Sedimentology, 46: 33–45. doi: 10.1046/j.1365-3091.1999.00201.x
- Issue published online: 5 JAN 2002
- Article first published online: 5 JAN 2002
- carbonate sediment;
- micrite envelopes;
- seagrass beds;
- sediment trapping
Micrite envelopes are a common feature in carbonate sediments and are typically associated with the micrite filling of borings produced by microendolithic organisms. These are referred to as ‘destructive micrite envelopes’ and have long been recognized as reflecting an important early diagenetic process. Recent analysis of sediments collected from back-reef environments at Discovery Bay, north Jamaica, however, has demonstrated ‘envelope’ formation on the surfaces of carbonate grains, clearly distinct from the micrite filling of microborings. Such constructive envelopes occur almost exclusively in sediments from grass-bed environments and are always intimately associated with ‘biofilms’ comprising abundant mucilage, cyanobacteria, bacteria and diatoms. It is suggested that these envelopes represent a product of both biologically mediated micrite precipitation (occurring within the biofilm mucilage and around the biofilm components, i.e. cyanobacteria and diatoms) and associated trapping of carbonate mud and fine-grained sediment. Their recognition only within grass-bed sediments may enable their use as a diagnostic feature of grass-bed environments or vegetation-stabilized substrates in the rock record.