Aberdeen - Geography

Geography

Being sited between two river mouths, the city has little natural exposure of bedrock. This leaves local geologists in a slight quandary: despite the high concentration of geoscientists in the area (courtesy of the oil industry), there is only a vague understanding of what underlies the city. To the south side of the city, coastal cliffs expose high-grade metamorphic rocks of the Grampian Group; to the south-west and west are extensive granites intruded into similar high-grade schists; to the north the metamorphics are intruded by gabbroic complexes instead. The small amount of geophysics done, and occasional building-related exposures, combined with small exposures in the banks of the River Don, suggest that it's actually sited on an inlier of Devonian "Old Red" sandstones and silts. The outskirts of the city spread beyond the (inferred) limits of the outlier onto the surrounding metamorphic/ igneous complexes formed during the Dalradian period (approximately 480-600 million years ago) with sporadic areas of igneous Diorite granites to be found, such as that at the Rubislaw quarry which was used to build much of the Victorian parts of the city.

On the coast, Aberdeen has a long sand beach between the two rivers, the Dee and the Don, which turns into high sand dunes north of the Don stretching as far as Fraserburgh; to the south of the Dee are steep rocky cliff faces with only minor pebble and shingle beaches in deep inlets. A number of granite outcrops along the south coast have been quarried in the past, making for spectacular scenery and good rock-climbing.

The city extends to 184.46 km2 (71.22 sq mi), and includes the former burghs of Old Aberdeen, New Aberdeen, Woodside and the Royal Burgh of Torry to the south of River Dee. In 2010 this gave the city a population density of 1,169 / km². The city is built on many hills, with the original beginnings of the city growing from Castle Hill, St. Catherine's Hill and Windmill Hill.