A STEP TOWARDS A MORE COHESIVE DEFINITION OF MICROBIALITE FABRICS

Historically, microbialites have been divided into four major categories--stromatolites, thrombolites, dendrolites, and leiolites--with stromatolites and thrombolites being the most common.The division of these structures is often complicated and confusing, as structures are rarely solely laminated, clotted, branching, or undifferentiated, but often a transition between two or more different fabrics.

Previous investigations (see Kennard and James 1986), use classification schemes for divisions of microbialites that have been followed inconsistently by many authors for several decades. To improve classification, we suggest simply using the term microbialite and including a comprehensive description of observable textures at the macro-, meso-, and microscale levels. By discontinuing the classification of microbialites into stromatolites et al., this will resolve the issues that arise from the description of stromatolites with clotted fabrics and thrombolites with laminations, which can impede appropriate interpretation. In addition, by utilizing one encompassing term, we will step away from the tendency to assign more specific terms as though they were taxonomic nomenclature.

In turning towards a description-based method, samples can be accurately and comprehensively described. For example, a sample that may have previously been identified as a 'thrombolite with some laminations', should now be more accurately described as a 'microbialite with 3-5mm pelloid shaped clots throughout approximately 70% of the sample and 1mm micritic laminations in the bottom 30% of the sample.' Broader terminology accompanied by short yet accurate descriptions will better represent microbialite types, preventing miscommunication in academic literature regarding processes leading to the formation of microbialite structures.