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Stromatolite Identification Site

Stromatolites are the fossilized remains of microbial life forms, primarily algae and cyanobacterial mats. A more formal definition has been "laminated organo-sedimentary structures formed by the trapping and binding, and/or precipitation of minerals by microorganisms". The above definition comes from a page on the NASA Astrobiology Institute web site. These microorganisms were among the earliest life forms to evolve on earth, some of them existing 3.5 billion years ago. Thus their remains give us the oldest large-scale evidence of life on earth.

The exploration of Mars will have as a key component exo-paleontology, or the search for evidence of off-planetary past life forms. There is evidence that oceans did exist at some point on Mars. A key question is whether they lasted long enough to enable primitive life forms to evolve. If they did evolve, then their evidence would presumably be left in a form similar to that on early earth, Mars stromatolites.

The search for evidence of past Martian life forms will be carried out by a series of Mars rovers, and at some point, Mars human explorers. Both Mars rover controllers and human explorers will be primarily engaged in sample collection for geological, paleontological and biological analysis. These samples will be either returned to earth or analyzed on-site. The ability of those choosing samples to recognize potential remains of primitive life forms is crucial to the success of these missions.

Thus familiarity with a wide variety of earth stromatolitic forms is a key component of the training of Mars rover controllers. This site attempts to display a wide variety of stromatolite forms to that end.


A number of classification systems have been put forward during the last century for stromatolites. Many of the characteristics used to classify stromatolites have depended on microscopic features. While these are useful for their intended purpose, the purpose of this site is to enable recognition of stromatolite forms in the field. Thus a very tentative classification system will be proposed based on macro features readily observable.


Click on the pictures for a larger view