Search results
Results from the WOW.Com Content Network
While features of some ancient apparent stromatolites are suggestive of biological activity, others possess features that are more consistent with abiotic (non-biological) precipitation. [17] Finding reliable ways to distinguish between biologically formed and abiotic stromatolites is an active area of research in geology.
Stromatolites are formed by some microbial mats as the microbes slowly move upwards to avoid being smothered by sediment. Microbial mats may also be referred to as algal mats and bacterial mats. They are a type of biofilm that is large enough to see with the naked eye and robust enough to survive moderate physical stresses.
Collenia are stromatolites made up of convex layers flattened in the center, forming columnar colonies. The microorganisms involved were likely photosynthetic bacteria expiring oxygen. The microorganisms involved were likely photosynthetic bacteria expiring oxygen.
The stromatolites found today are almost all carbonate rocks (made of limestone), but these structures are mostly composed of the minerals gypsum and halite (rock salt), Hynek said.
Stromatolites are alternating layers of cyanobacteria and sediments. The grain size of sediment portion of stromatolites is affected by the depositional environment. During the Proterozoic, stromatolites' compositions were dominated by micrite and thinly laminated lime mud, with thicknesses no greater than 100 microns. [3]
move to sidebar hide. ... Pages in category "Stromatolites" The following 7 pages are in this category, out of 7 total. This list may not reflect recent changes. ...
"Spongiostromata" is an antiquated form taxon that refers primarily to fossil cyanobacteria. "Spongiostromate" is also used to describe stromatolites and oncolites that do not preserve clear tubules or other cellular microstructure.
The domal morphology of biological stromatolites is the result of the vertical growth necessary for the continued infiltration of sunlight to the organisms for photosynthesis. Layered spherical growth structures termed oncolites are similar to stromatolites and are also known from the fossil record .