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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.
Algal mats are one of many types of microbial mat that forms on the surface of water or rocks. They are typically composed of blue-green cyanobacteria and sediments. Formation occurs when alternating layers of blue-green bacteria and sediments are deposited or grow in place, creating dark-laminated layers. Stromatolites are prime examples of ...
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.
The lowermost of three stratigraphic units that comprise the Dresser Formation contains some of the Earth's earliest commonly accepted evidence of life such as morphologically diverse stromatolites, microbially induced sedimentary structures, putative organic microfossils, and biologically fractionated carbon and sulfur isotopic data. [1] [2 ...
These possible biosignatures include: (a) microfossils and stromatolites; (b) molecular structures and isotopic compositions of carbon, nitrogen and hydrogen in organic matter; (c) multiple sulfur and oxygen isotope ratios of minerals; and (d) abundance relationships and isotopic compositions of redox-sensitive metals (e.g., Fe, Mo, Cr, and ...
Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria. [108] Stromatolites provide some of the most ancient fossil records of life on Earth, dating back more than 3.5 billion years ago. [109]
Stromatolites – laminated microbialites (Precambrian silicified stromatolite, Strelley Pool Chert, (Pilbara Craton), W. Australia) Microbialite is a benthic sedimentary deposit made of carbonate mud (particle diameter less than 5 μm ) that is formed with the mediation of microbes .
One biological system that might be of key importance in the future development of architecture is bacterial biofilm. The term biofilm refers to complex heterogeneous structures comprising different populations of microorganisms that attach and form a community on inert (e.g. rocks, glass, plastic) or organic (e.g. skin, cuticle, mucosa) surfaces.