A day on a Jurassic Beach.
From south of Helmsdale north to the Ord of Caithness the rocky foreshore is a wave-cut platform of Jurassic (Kimmeridgian) rocks. TDFC members walked north from Helmsdale looking for fossils, for birds and other wildlife, and looking in detail at the silty or sandy bedding, or the breccias and conglomerates standing above them.
The Helmsdale Fault is present just on-shore showing a steep scarp slope facing the sea,
and much evidence in the conglomerate or the siltstone (1st picture above) deposited below the fault by eroded and falling detritus (like the ‘fallen sea stack’ below).
The Helmsdale fault is associated with the Great Glen Fault , running from near Dingwall, through the Struie Ridge, to this shoreline and out to sea below the Ord of Caithness.
The Kimmeridgian strata sloping up to the rocky wave-cut platform appear curved, as below.
This is possibly due to strains imposed by being near to the moving fault. As these beds slope eastwards down below the Moray Firth and the North Sea they become the source rock for 95% of the oil found offshore. Around the world rocks of this age are now home to many dinosaurs, large and small, marine and terrestrial.
Many examples of Jurassic ‘wood’ were found, some brown lithified rock and some carbon-black appearing objects embedded in sandy siltstones.
Several fine coral assemblages were found, and many examples of crushed bi-valves in a silty matrix. Here are a fine coral and an ammonite.
Thankfully this was a fine, sunny, cool February day for looking at these rocks and birds like a single early Gannet. And a fine lunch spot.
And, other wildlife was found (Anguis fragilis):-