stromatolite
stroh-MAT-uh-lite
Definition
A layered, fossilized sedimentary structure formed over long periods by the growth and activity of microbial mats, such as cyanobacteria.
Etymology
The word is derived from the Greek 'stroma,' meaning 'layer' or 'mattress,' and 'lithos,' meaning 'stone.' It was coined to describe the characteristic layered appearance of these rocky structures.
In the news
In this article, stromatolites are mentioned as a source of growth bands that researchers use to estimate the length of ancient days, although the data extracted from them is noted as potentially uncertain.
For roughly a billion years of Earth’s deep past, the Moon’s ocean tides may have slowed the planet while a Sun-driven atmospheric tide sped it up, holding the day near 19 hours — but the rocks preserve a hypothesis, not a stopwatch
Read the full article ↗Space Daily