The geology of County Durham in northeast England consists of a basement of Lower Palaeozoic rocks overlain by a varying thickness of Carboniferous and Permo-Triassic sedimentary rocks which dip generally eastwards towards the North Sea. These have been intruded by a pluton, sills and dykes at various times from the Devonian Period to the Palaeogene. The whole is overlain by a suite of unconsolidated deposits of Quaternary age arising from glaciation and from other processes operating during the post-glacial period to the present.[1] The geological interest of the west of the county was recognised by the designation in 2003 of the North Pennines Area of Outstanding Natural Beauty as a European Geopark.
The word 'geology' may be traced back to a coinage of Richard de Bury who was a Bishop of Durham in the 14th century. He introduced the term geologia in his work The Philobiblon which he explained as 'the earthly science'.[2]: 8