The natural landscape is simply a reflection of geology and climate.
The 90 square kilometres of land forming West Penwith comprises land to west of the river Hayle. It is also known as the Lands End Peninsula.
Zennor Parish contains what many see as the principle characteristics at the heart of the landscape of West Penwith. It is bounded by Atlantic facing cliffs to the north; a coastal plateau above the cliffs and steep slopes up to the high moorlands to the parish boundary 3.5km from the sea.
Except at the headlands, the cliffs are rarely more than around 30 metres high and are buttressed by Gurnard’s Head to the west and Zennor Head to the east of the village. Above the cliffs the land slopes up up to the narrow (0.7km to 2km) plateau around the 100m contour on which Zennor is located. This forms the strip of more readily cultivatable land. This has been farmed from the Bronze Age to the present day and many of the field boundaries date back beyond the Iron Age. At one stage in its evolution, before the last Ice Age, it was sea-bed with the slopes behind forming the ancient coastline. Zennor Hill, Carn Galver and Watch Croft were the headlands at that time.
Moving further inland the slope increases and for the most part cultivation gives way to moorland. Remains of field boundaries show that areas which were formally cultivated have now returned to moorland. Part of the southern boundary of the parish follows the old droveway of the Tinner’s Way. This is also the watershed for run-off, feeding streams flowing to the northern coast and those heading south.
The dominant stream in the parish is the one flowing down the Foage Valley and this has its catchment on the north facing slopes and the high moorland. In common with many steams fed by small peaky catchments it reacts quickly to rainfall events and this causes flash flooding both in the village and the Foage Valley.
The geology is almost exclusively Granite though in places the cliffs expose the edge of the granite intrusion. It is in these zones that mineralisation is found and exploited. A good example of coastal mining is the Gurnard’s Head Mine which mined for copper and tin. Some mineralisation is also found in the granite itself further inland, though this is rare, e.g as exploited at Rosevale Mine in the Foage Valley and the Lady Downs Mine, or Wheal Lady on the inland high moors. Alluvium is present along the streams and these may well have been exploited for tin and copper by small scale streaming operations.
Climate changes drives temperature and this in turn controls sea water levels as the ice-cap areas vary in response to temperature changes. We can see this at Zennor. The ancient inland abandoned cliff line shows that sea levels have fallen by at least 100m since the sea last crashed into them during winter storms. For a sense of proportion, UK predictions for rises in sea level are for 12cm (high probability) and 76 cm (low probability) for the period 1990–2095.
The geologically recent climate changes have been those that resulted in the Ice Ages the last of which ended around 12,000 years ago. Some major changes are even more recent as it was only 6,000 years ago that the chalk from Dover to Cape Griz Nez was breached and the English Channel formed.
During the cold periods of glacial advance, water was locked up in the ice caps as well as in glaciers and ice sheets on the land masses; sea level fell by 135 metres. During the periods of ice advance the sea level fluctuated wildly. There is no evidence that permanent ice caps were present on the high moors behind Zennor.
The climate would have been like areas of Northern Canada and Siberia with the ground permanently frozen during periods of glacial advance, and seasonally frozen when the ice receded. There would have been many, many cycles of this over the 2.6 million year period of the Ice Age. On the higher ground the tors would have been frost shattered and on the slopes the granite would have been weathered by frost action, maybe down to several metres. During the seasonal thaws the topsoil decomposed and highly weathered granite, known locally as ‘rab’, would have slowly slumped down the steeper slopes and accumulated on the narrow coastal plain. This would have improved subsequent cultivatability at the expense of a liberal accumulation of boulders brought down from the frost shattered tors.
Later as temperature rose at the end of the Ice Age there was a long period of forestation.
What do we see when we walk around Zennor Parish? An unchanging landscape with continuous farming since the Bronze Age; waves crashing against the bastion of granite cliffs; and with exception of localised flooding a benign environment; traces of mining adequate to be interesting and picturesque though not disfiguring? Look a bit closer, and the evidence is there to be read. We actually have a landscape in continual change. The sea level has ranged from 100m above to 100m below current level. Many of the parishioners live on an old seabed with abandoned seas cliffs behind them. Frost, ice and landslides have smoothed out the inland areas of the parish leaving the present day landscape.