Loire

Geography

The source of the river lies in the eastern Massif Central, in springs to the south side of Mont Gerbier de Jonc at 44°50′38″N 4°13′12″E. This lies in the north-eastern part of the southern Cévennes highlands, in the Ardèche commune of Sainte-Eulalie of southeastern France. It is originally a mere trickle of water located at 1,408 m (4,619 ft) above sea-level. The presence of an aquifer under Mont Gerbier de Jonc gives rise to multiple sources, three of them located at the foot of Mount have been highlighted as river sources. The three streams converge to form the Loire, which descends the valley south of Mount through the village of Sainte-Eulalie itself.

History

Studies of the palaeo-geography of the region suggest that the palaeo-Loire flowed northward and joined the Seine, while the lower Loire found its source upstream of Orléans in the region of Gien, flowing westward along the present course. At a certain point during the long history of uplift in the Paris Basin, the lower, Atlantic Loire captured the "palaeo-Loire" or Loire séquanaise ("Seine Loire"), producing the present river. The former bed of the Loire séquanaise is occupied by the Loing.

The Loire Valley has been inhabited since the Middle Palaeolithic period from 40 to 90 ka. Neanderthal man used stone tools to fashion boats out of tree trunks and navigated the river. Modern man inhabited the Loire valley around 30 ka.

Geology

The geological formations in the Loire river basin can be grouped into two sets of formations, namely, the basement domain and the domain of sedimentary formations. The basement domain primarily consists of metamorphic and siliceous fragmented rocks with groundwater occurring in fissures. The sedimentary domain consists of limestone and carbonaceous rocks, that, where saturated, form productive aquifers. Rock outcrops of granite or basalt also are exposed in the river bed in several stretches.

The middle stretches of the river have many limestone caves which were inhabited by humans in the prehistoric era; the caves are several types of limestone formations, namely tuffeau (a porous type of chalk, not to be confused with tufa) and Falun (formed 12 million years ago).

Climate

The French language adjective ligérien is derived from the name of the Loire, as in le climat ligérien ("the climate of the Loire Valley"). The climate is considered the most pleasant of northern France, with warmer winters and, more generally, fewer extremes in temperatures, rarely exceeding 38 °C (100 °F). It is identified as temperate maritime climate, and is characterised by the lack of dry seasons and by heavy rains and snowfall in winter, especially in the upper streams. The number of sunny hours per year varies between 1400 and 2200 and increases from northwest to southeast.