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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 mineral ions introduced during remineralisation restore the structure of the hydroxyapatite crystals. [36] The clubbing appendages of the peacock mantis shrimp are made of an extremely dense form of the mineral which has a higher specific strength; this has led to its investigation for potential synthesis and engineering use. [37]
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 .
Lichen stromatolites are laminar calcretes that are proposed as being formed by a sequence of repetitions of induration followed by lichen colonization. Endolithic lichens inhabit areas between grains of rock, chemically and physically weathering that rock, leaving a rind, which is then indurated (hardened), then recolonized.
Pages in category "Stromatolites" The following 7 pages are in this category, out of 7 total. This list may not reflect recent changes. ...
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