The history of the Cornish rocks is an epic tale demonstrating the effects of climate change and environmental forces over many millions of years. The story begins around 400 million years ago with the deposition of sand, shale and mud on the bed of a deep tropical ocean south of the equator. The layers show as bands - graded according to the courseness of the grains and are called turbidites.The sub-marine layers of sediment built up and gradually compacted into rock. Meanwhile, the ocean bed, with its sediments, was gradually transported north by tectonic movements.
During the 8,000-mile journey, the sedimentary rocks were exposed to extreme pressure and temperature causing ripples, buckling and faults and the resulting metamorphic rocks were eventually elevated above sea level. Cornwall was emerging from beneath the waves!
The drama was not yet over as, with the intrusion of magma rising from deep inside the earth around 290 million years ago, the Cornish rocks were again subjected to pressure and high temperatures. Hot water generated by the magma transported melted minerals into cracks in the surrounding rocks forming layers of mineral ore and the sparkling white quartz veins.
Over the subsequent years, the rocks continued to be subjected to erosion and weathering - processes which continue to this day - but the patterns and structures formed all those years ago can still be clearly seen on display in all their glory!