The Bode Gorge () is a long ravine that forms part of the Bode valley between Treseburg and Thale in the Harz Mountains of central Germany. The German term, Bodetal (literally "Bode Valley"), is also used in a wider sense to refer to the valleys of the Warme and Kalte Bode rivers that feed the River Bode. At the Bode Gorge, the River Bode, which rises on the highest mountain in the Harz, the Brocken, has cut deeply into the hard Ramberg granite rock. The ravine is about 140 m deep at Treseburg and some 280 m deep at Thale where it breaks out into the Harz Foreland. The Bode Gorge was designated a nature reserve as early as 5 March 1937; its boundaries being subsequently expanded. With an area of, currently , it is one of the largest nature reserves in Saxony-Anhalt. Geology Apart from intrusions of Ramberg granite, which rose to the surface and solidified 300 million years ago in the Upper Carboniferous Period, and their associated veins of quartz, the ravine of the Bode also cuts through hornfels and knotenschiefer (a type of slate), as well as argillite and graywacke with quartz elements and diabase dikes from the Devonian Period, 400 to 370 million years ago. Ramberg granite predominantly forms the front section of the ravine and characterises its highest rocks. It appears light-coloured due to the high proportion of white feldspar. The quartz lends it a grey shade. The proportion of black mica (biotite) is low and carries no weight in terms of colouring. The light-coloured granite stands out from the dark to black coloured rocks of hornfels and argillite. As a result, the front section of the ravine and the river bed of the Bode in this area appear clearly lighter than the rear section. The argillite at the rear of the gorge shows bands of colour in places that evinces the former strata of the marine sediments. The stratified slate was only slightly metamorphosed. Climate In the area of the Bode Gorge average annual temperatures range from 8 °C down to 6.5 °C and annual precipitation between 600 and 720 mm. But sharp, local differences in the ravine between, for example, the sunny, warm and dry southern slopes and the more shaded, cooler and damper northern slopes and valley floor, modify the local climate considerably. Soils The most common soil types are silicate leptosols,