الرقائق الكلسية الطحلبية
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stromatolite
■ noun Biology a calcareous mound built up of layers of blue-green algae and trapped sediment, especially as fossilized in Precambrian rocks.


1930s: from mod. L. stroma, stromat- 'layer, covering' + -lite.

© Oxford University Press, 2004
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stromatolite

Layered deposit, mainly of limestone, formed by the growth of blue-green algae (see cyanobacteria).

These structures are usually characterized by thin, alternating light and dark layers that may be flat, hummocky, or dome-shaped. Stromatolites were common in Precambrian time (more than 543 million years ago). Some of the first forms of life on Earth are recorded in stromatolites in rocks 3.5 billion years old. Stromatolites continue to form in certain areas today, most abundantly in Shark Bay in western Australia.

© 2005 Encyclopædia Britannica, Inc.
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stro·mat·o·lite
Pronunciation: strō-'ma-tə-ˌlīt
Function: noun
Etymology: Latin stromat-, stroma bed covering + English -o- + -lite
Date: 1930

: a laminated usually mounded sedimentary fossil formed from layers of cyanobacteria, calcium carbonate, and trapped sediment
–stro·mat·o·lit·ic \-ˌma-tə-'li-tik\ adjective

© 2005 Merriam-Webster, Incorporated

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