I’ve talked before about the importance of getting out in the field for both ecologists and geologists (see Fieldwork versus virtual reality and A day at the seaside) and, as John and I have now taken students on our trip to Alnwick for five summers in a row, we think maybe it’s time to branch out and offer something different for those who can’t come to the Himalayas with us. We’ve settled on the Fife coast as an area John knows well; there are igneous rocks to complement the sediments we look at around Howick Bay and sand dunes and salt marsh at Tentsmuir to keep me happy.
To this end, we spent a couple of days in August walking parts of the Fife coastal path between St Andrews and Kincraig Point, looking for suitable locations – there are no shortage! Whereas at Howick Bay, near Alnwick, we have focussed on the extensive series of sedimentary rocks exposed at low tide the East Neuk, or corner, of Fife is renowned for its volcanic rocks.
Looking south from Howick Bay, Northumberland
Kincraig neck, a volcanic plug near Elie on the Fife coast
As at Alnwick, these rocks were mostly formed more than 300 million years ago during the Carboniferous Period. This time we’ll be taking a closer look at some of the volcanic rocks associated with Carboniferous sediments – the red patches on the old geological map below.
Kincraig neck, near Elie, is perhaps the most spectacular of the old volcanoes, with columnar jointed basalt reminiscent of Fingal’s cave on Staffa or the Giant’s Causeway in Northern Ireland.
Basalt forms these mostly-hexagonal columns when a thick layer of molten rock cools and contracts relatively quickly. Except at very low tide, the remains of the old volcano are only accessible via the chain walk along the bottom of the cliff west of Elie. This is just what it says on the can – a series of chains fastened to near vertical rock faces which you need to cling to to make your way along. We’ll be making sure the tide is low when we take students there!
Macduff’s Cave, Elie chain walk
We’ll also visit the iconic ‘Rock and Spindle’ formation on the coast east of St Andrews. The low stack is composed of layers of volcanic ash from a nearby vent, whilst the radiating spokes of the ‘Spindle’ are columnar jointed basalt formed as the last pulse of molten rock extruded solidified inside the vent, supposedly looking like a spinning wheel.
We’ll also see the effect of volcanic intrusions on the surrounding sediments, for example at St Monans where the top of the intruded basalt is surrounded by sandstones dipping symmetrically outwards in all directions.
The sediments themselves, particularly around St Monans, also tell important stories of their own – limestones full of corals such as Syphonodendron were laid down under the sea whilst some sandstones show clear cross-bedding, perhaps indicating a coastal origin where tides ebbed and flowed.
Cross-bedded sediments near St Monans
For some of us, the Elie Rubies which can be found on the beach near Lady’s Tower might be a big a draw!
South across the Firth of Forth from Lady’s Tower, Elie
We saw plenty of plants as we walked along the coast, particularly on the rich soils on volcanic ash around the vents.
Left: assemblage including Viper’s Bugloss, Echium vulgare, and right: Hare’s-foot clover, Trifolium arvense, both around Kincraig neck
However, for our purposes, the most interesting place botanically is the salt marsh and sand dunes of Tentsmuir nature reserve, just west of St Andrews at the mouth of the Tay estuary. Here we’ll be able to look at some of the specialist plants adapted to the salty soils around the lagoons behind the dunes and also see the process of succession in action.
Purple glasswort (Salicornia ramosissima) on salt marshes at Tentsmuir
Plants like glasswort have to cope with the problem of extracting the fresh water they need to survive from water in the soil which can be considerably more concentrated than seawater, due to evaporation. Like the Halogeton glomeratus we found in Kashmir, Salicornia can take up and sequester toxic salts out of harm’s way in the cell vacuoles of their fleshy leaves.
Looking across the dunes from where they start, above the high water mark, we will be able to see how grasses such as sand couch and marram first stabilise the dunes and then, as organic matter starts to accumulate, other plants are able to gain a foothold. Sand dunes are amongst the best places to see primary colonisation and succession in action.
Developing dunes and succession behind the dunes at Tentsmuir
One of the best pieces of evidence for the rate at which sand dunes form and are stabilised into more ‘permanent’ land comes from the WW2 machine gun posts which now have their view seawards completely blocked by dunes!
The grassland behind the dunes is now something of a botanist’s paradise, with plants such as Seaside Centaury, Grass of Parnassus, Blue Fleabane and Knotted Pearlwort flourishing in sheltered spots.
Left to right: Blue Fleabane, (Erigeron acer), Grass of Parnassus, (Parnassia palustris), Knotted Pearlwort, (Sagina nodosa) and Seaside Centaury (Centaurium littorale)
Walking back to the car through the coniferous woodland which fills the headland inland of the dunes was an added pleasure on the sunny August afternoon we visited – glades full of ragwort and thistles fed plenty of Red admiral, Tortoiseshell and Peacock butterflies and the year’s first mushrooms were already appearing.
If all goes smoothly, we’re planning on making time, too, for a look at the diversity of life in rockpools near Elie – who isn’t captivated by marine life after David Attenborough’s ‘Blue Planet 2’? Next summer’s first trip to the area with students should give a good overview of the geology and ecology of this beautiful area of Scotland and illustrate how closely the two are linked.