Ardtun Leaf Beds
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Condition (NatureScot)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| F1 | Palaeoentomology | Favourable | — | 2009-06-24 |
| F2 | Tertiary Igneous | Favourable | — | 2013-01-18 |
| F3 | Tertiary Palaeobotany | Favourable | — | 2009-06-24 |
Climate exposure
This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.
Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.
Geology & landscape
Rock Type: Basalt
Landscape processes: Coastal, Volcanic / Igneous
Description
ARDTUN LEAF BEDS Ardtun Leaf Beds Site of Special Scientific Interest is situated on the northern coastline of the Ardtun Penninsula, on the Isle of Mull. Coastal cliffs and gullies display exposures of internationally famous sediments lying between columnar basalt lava flows which erupted from the Mull volcano. The relationships of the sediments to the volcanic rocks provide valuable evidence in reconstructing the geography of Mull during the Tertiary geological period around 60 million years ago. Sedimentary rocks were deposited in a lake environment within the volcanic landscape and contain exceptionally well preserved fossilised tree foliage in addition to a diverse range of fossilised insect remains. Ardtun is a key site for Tertiary palaeobotany in Britain. A wide variety of fossil plants are found here in sediments deposited between successive lava flows. At least twenty species of plants including equisetes, ferns, conifers, ginkgos and dicotyledonous angiosperms occur here, represented by foliage, fruits and stems. The assemblage indicates a warm temperate climate. It is the only locality in Britain to have yielded such a flora, contrasting with the English assemblages of this age which are tropical or subtropical in aspect. The insect fauna recorded here is the most diverse known in the country from such early Tertiary strata, and it has no equivalents in the coeval deposits of southern Britain. The fauna is of interest because of its northerly latitude and because it includes a species of Cicada, Eotettigarcata scotica, a member of a family now confined to south-east Australia, also present is an early representative of the Orthoptera, of the family Gryllacrididae, a family which includes a small group of cryptic species, today typical of warm climates.