Figure 25

Microbial mats and other sedimentary-biological features. Examples of modern bio-sedimentary components of the salt lakes of the northern Great Plains of western Canada. A and B. Modern bio-sedimentary facies in Freefight Lake. Colluvium and mudflats/salt flats grade basinward into a 50 meter wide zone of microbial mats and then into deepwater basinal facies. C. Example of microbial mat material ripped up by wave agitation. D, E, and F. Examples of microbial and vegetation mats from saline lakes in the Great Plains. Note the laminated nature of the sediment immediately below the modern mat in F. Carbonate mineral diagenesis in this environment has created a considerable range and diversity of authigenic species (see also Figure 22). G. Hopper shaped mirabilite crystal incorporating Artemia sp. H. Bio-induced early diagenetic pyrite filling a diatom frustrule. I. Hopper shaped salt crystals floating at the surface of a brine pool. The red colouration of the water is due to the high abundance of Artemia sp.