The Rhynie chert is a rock containing exceptionally
well-preserved fossil plants and
animals (arthropods).
It is found near the village of Rhynie, Aberdeenshire, Scotland
[map].
Discovered in 1912 by Dr William Mackie [History].
Chert is a hard silica-rich rock.
The age of the chert is Early Devonian (Pragian): between
400 and 412 Million
years old [timescale].
At this time Scotland was situated around 28o
south of the equator as part of a huge continent made up of northern Europe,
North America and Greenland, called Laurussia [palaeogeographic
map].
The cherts are altered siliceous sinters deposited by hot
springs and geysers similar to those active today in Yellowstone National
Park, USA.
The sinters coated and fossilised plants and animals
preserving them in amazing detail.
The plant and animal fossils are important because they were
some of the earliest colonisers of the land.
The fossils help us reconstruct early land-based ecosystems.
The oldest 'insect' fossils known, Rhyniella (a type
of springtail) and Rhyniognatha (a primitive pterygote insect), have
been found
in the Rhynie chert.
The flora includes seven named higher land plants, all less
than 40 cm tall. [plants].
At least fifteen different (valid) named species of early terrestrial and freshwater
arthropods have been described from the chert, and still more are currently
being described or await publication [animals].
Algae, fungi, a lichen and various bacteria are also
fossilised in the chert.
The hot spring waters that deposited the sinter contained
gold, arsenic, antimony and other metals.
The Rhynie chert is the oldest hot spring system known anywhere in the
world where
surface features such as geyser vents are preserved.
