Geological Timeline - North West Highlands Geopark

volcanoes erupt off the west coast as the North Atlantic Ocean continues to widen
most of chalk limestone removed by erosion as sea level falls
climate cools

climate warm and humid
sea level much higher than today
thick layers of chalk limestone laid down on seabed over much of what is now Scotland

no rocks of this age in NW Highlands
evidence elsewhere in Scotland of inland deserts with tropical swamps on the coast and reefs
offshore widespread volcanic activity in rest of Scotland

Durness Limestone (carbonates) deposition ends about 490 million years ago as land is pushed up and sea retreats
major mountain chain created where Highlands are now
rapid erosion of uplifted land
Moine Thrust formed as rocks from the east (Moine Schists) were pushed westwards, sliding over the top of NW Highlands rocks

beach sands laid down on coastal fringes of large continent (to create Basal Quartzite, Pipe Rock and Salterella Grit formations)
mudstones (Fucoid Beds), and carbonates (Durness Limestone) laid down when sea level rose and water was deeper
worms burrowing in beach sands leave first evidence of life in this area

Lewisian Gneisses represent ancient rocks formed up to 3000 million years ago
much later, around 800 to 1000 million years ago, the rocks that are now the Moine Schists were laid down away to the east as layer upon layer of sand and silt; they were then pushed down into the Earth’s crust and changed into their present form
at about the same time, Torridonian Sandstones were laid down to the west as river sands and gravels in a desert environment; unlike the Moine Schists, they escaped being altered

Ceann an Iar Thuath na Gàidhealtachd tro na Linntean

bholcànothan a’ spreadhadh air an taobh an iar
agus Ceann a Tuath a’ Chuain Shiar a’ cumail a’ fàs nas motha
chuir bleith às dhan mhòrchuid de chloich-aoil chailce nuair a chaidh àirde na mara sìos
a’ ghnàth-shìde a’ fàs fionnar

a’ ghnàth-shìde blàth is tais
am muir gu math nas àirde na tha e an-diugh
fillidhean tiugha de chloich-aoil chailce gan cur air grunnd na marasa mhòrchuid dhen àite ris an canar Alba an-diugh

chan eil creagan dhen aois seo air taobh an Iar Thuath na Gàidhealtachd
fianais ann an àitichean eile ann an Alba mu fhàsaichean a-staigh air an dùthaich le boglaichean tropaigeach air a’ chladach agus sgeirean far a’ chladaich
tòrr bholcànothan sa chòrr de dh’Alba

sguir Clach-aoil Dhiùranais ga cur sìos o chionn 490 millean bliadhna no mar sin nuair a chaidh talamh a phutadh suas agus a chaidh am muir air ais
chaidh sreath mòr bheanntan a chruthachadh far a bheil a’ Ghàidhealtachd an-diugh
an talamh a chuireadh suas ga bhleith gu luath
Sàthadh na Mòine air a chruthachadh nuair a chaidh creagan on ear (Schistean na Mòine) a phutadh dhan iar, a’ sleamhnachadh thairis air creagan cheann an Iar Thuath na Gàidhealtachd

gainmheach na tràghad ga cur sìos air cladaichean na mòr-roinn (a chruthaich cumaidhean de Bhun Chlach-èiteig, Creag Phìobachch agus Grinneal Salterella)
clachan-eabair (Imirean Fucoid), agus clachan-aoil (Clach-aoil Dhiùranais) air an cur sìos nuair a dh’èirich àirde na mara agus a bha an t-uisge na bu dhoimhne
’s e boiteagan a’cladhach san tràigh a’chiadh fhianais air beatha san sgìre seo

Gneisses Leodhasach a’ riochdachadh sheann chreagan a chaidh a chruthachadh suas gu chionn 3000 millean bliadhna
Ùine mhòr an dèidh sin, o chionn 800 is 1000 millean bliadhna, chuireadh sìos na creagan a tha a-nis ann an Schistean na Mòine ris an ear mar fhilleadh air muin fillidh de ghainmhich is de dh’eabar; chaidh an uair sin am putadh sìos do rùsg na Talmhaainn agus dh’atharraich an cruth gu bhith mar a tha iad an-diugh
Mun aon àm, chuireadh sìos clachan-gainmhche Thoirbheartain ris an ear mar ghainmhich aibhne is grinneal ann an talamh fàsaich; ach cha do dh’atharraich iad sin mar a dh’atharraich Schistean na Mòine