Syncline in the context of "Somme (river)"

A structural basin is a large-scale structural formation of rock strata formed by tectonic warping (folding) of previously flat-lying strata into a syncline fold. They are geological depressions, the inverse of domes. Elongated structural basins are a type of geological trough. Some structural basins are sedimentary basins, aggregations of sediment that filled up a depression or accumulated in an area; others were formed by tectonic events long after the sedimentary layers were deposited.

Basins may appear on a geologic map as roughly circular or elliptical, with concentric layers. Because the strata dip toward the center, the exposed strata in a basin are progressively younger from the outside in, with the youngest rocks in the center. Basins are often large in areal extent, often hundreds of kilometers across.

The Highland Boundary Fault is a major fault zone that traverses Scotland from Arran and Helensburgh on the west coast to Stonehaven in the east. It separates two different geological terranes which give rise to two distinct physiographic terrains: the Highlands and the Lowlands, and in most places it is recognisable as a change in topography. Where rivers cross the fault, they often pass through gorges, and the associated waterfalls can be a barrier to salmon migration.

The fault is believed to have formed in conjunction with the Strathmore syncline to the south-east during the Acadian orogeny in a transpressive regime that caused the uplift of the Grampian block and a small sinistral movement on the Highland Boundary Fault.

A double summit, double peak, twin summit, or twin peak is a mountain or hill that has two summits, separated by a col or saddle.

One well-known double summit is Austria's highest mountain, the Großglockner, where the main summit of the Großglockner is separated from that of the Kleinglockner by the Glocknerscharte col in the area of a geological fault. Other double summits have resulted from geological folding. For example, on Mont Withrow in British Columbia, resistant sandstones form the limbs of the double summit, whilst the softer rock in the core of the fold was eroded.

Provadia (Bulgarian: Провадия [proˈvadijɐ]) is a town in northeastern Bulgaria, part of Varna Province, located in a deep karst gorge (Provadia syncline) along the Provadiya River not far from the Bulgarian Black Sea Coast. It is the administrative centre of Provadia Municipality. As of December 2009, the town had a population of 12,901.

Provadia served as a customs point since ancient times. It is well known for salty mineral waters, its mild climate and a total of 70 km of caves in the surrounding mountain walls. It can be reached by train from Sofia or Varna and there are also hourly buses from and to Varna, and a sophisticated road system.

This list of North American deserts identifies areas of the continent that receive less than 10 in (250 mm) annual precipitation. The "North American Desert" is also the term for a large U.S. Level 1 ecoregion (EPA) of the North American Cordillera, in the Deserts and xeric shrublands biome (WWF). The continent's deserts are largely between the Rocky Mountains and Sierra Madre Oriental on the east, and the rain shadow–creating Cascades, Sierra Nevada, Transverse, and Peninsular Ranges on the west. The North American xeric region of over 95,751 sq mi (247,990 km) includes three major deserts, numerous smaller deserts, and large non-desert arid regions in the Western United States and in northeastern, central, and northwestern Mexico.