Rhynie Chert

Site of Special Scientific Interest · 57.3372, -2.8411

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Aberdeenshire County

Condition (NatureScot)

Favourable (4)
UnitFeatureConditionArea (ha)Assessed
F1 Arthropoda (excluding insects and trilobites) Favourable — 2009-04-17
F2 Non-marine Devonian Favourable — 2017-03-17
F3 Palaeoentomology Favourable — 2009-04-17
F4 Palaeozoic Palaeobotany Favourable — 2010-03-17

Habitats

Fast flowing river and stream

Geology & landscape

Geological Period: Devonian · Rock Type: Chert

Landscape processes: Fluvial, Volcanic / Igneous

Description

Rhynie Chert Rhynie is located 13 km south of Huntly. Rhynie Chert SSSI is one of the most important sites in the world for fossils of the earliest-known land plants and associated micro-fauna. The site represents one of the best examples of a complete terrestrial wetland ecosystem of the Devonian period. Stratigraphy Non-marine Devonian The Rhynie Chert, formed around 410 million years ago, is one of the earliest-known occurrences of the surface expressions of a hydrothermal spring system, and represents the fossil remains of an entire terrestrial wetland ecosystem preserved in place. The fossil-bearing cherts occur in a sequence of rocks that record an evolving environment, in a semi-arid and seasonally wet climate. River-formed alluvial fans, were followed by eruption of lava, and an alluvial plain with ephemeral lakes and ponds. Hot springs on the alluvial plain deposited a crust of porous silica (sinter) and preserved the existing ecosystems. Palaeontology The Rhynie Chert is an internationally important ‘Lagerstätte’, with an abundance and variety of plant and invertebrate fossils, all preserved in exquisite detail including soft body parts down to the cellular level. The site is crucial for understanding the development of life on land. Palaeozoic Palaeobotany The chert yields fossils of some of the oldest-known land plants in which full anatomical details are preserved. It is therefore of paramount importance in an understanding of the early Tracheophyta and plant evolution. The Rhynie assemblage of Rhynia, Horneophyton, Nothia and Asteroxylon has not yet been recorded in Devonian rocks anywhere else in the world. Arthropoda (excluding insects and trilobites) In addition, the site is so far the finest in the world (and the first to be discovered) for fossils of Devonian microarthropods. Thirteen species of chelicerate and one crustacean have been described from the site. Palaeoentomology The chert is also world famous for yielding fossils of the earliest known insect, Rhyniella praecursor, a wingless insect only 1.5 mm long.

Plant communities

A9 — Fast flowing river and stream, Marginal and inundation, Pond ditch and canal, Sluggish river and stream

Potamogeton natans community

Schoenoplectus lacustris, Juncus bulbosus, Sparganium angustifolium, Sparganium erectum, Sparganium minimum, Alisma plantago-aquatica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Elodea canadensis, Lemna minor, Lemna trisulca, Nymphaea alba, Callitriche platycarpa, Callitriche stagnalis, Littorella uniflora, Potamogeton natans, Ranunculus trichophyllus, Glyceria fluitans, Chara subspinosa

A14 — Fast flowing river and stream

Myriophyllum alterniflorum community

Isolepis fluitans, Juncus bulbosus, Fontinalis antipyretica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Lemna minor, Callitriche stagnalis, Littorella uniflora, Potamogeton filiformis, Potamogeton gramineus, Potamogeton natans, Ranunculus peltatus, Chara spp., Nitella hyalina

A17 — Chalk river and stream, Fast flowing river and stream

Ranunculus penicillatus ssp. pseudofluitans community

Berula erecta, Nasturtium officinale, Elodea canadensis, Lemna minor, Callitriche stagnalis, Veronica beccabunga, Polygonum amphibium, Polygonum hydropiper, Potamogeton crispus, Potamogeton pectinatus, Ranunculus penicillatus ssp. pseudofluitans

A18 — Fast flowing river and stream

Ranunculus fluitans community

Fontinalis antipyretica, Fontinalis squamosa var. curnowii, Myriophyllum alterniflorum, Myriophyllum spicatum, Elodea canadensis, Mentha aquatica, Lemna gibba, Lemna minor, Potamogeton perfoliatus, Ranunculus fluitans, Glyceria fluitans, Phalaris arundinacea