Description
Sandstone is a sedimentary rock composed primarily of sand grains. During the sedimentation of sand grains, silt, limestone, gravel, mica, feldspar, and other rock fragments are also deposited. Weathering turns an originally yellow-brown sandstone gray. The presence of certain oxides and other minerals gives some variants a brownish-red color. Sandstone consists primarily of quartz. Sandstone is widely used as a building material in the Netherlands and Belgium. In the Netherlands, Bentheimer sandstone (from Bentheim) and Obernkirchener sandstone (from Obernkirchen) are primarily used, and for sculptures, the fine-grained Baumberger sandstone, due to its high lime content, is also used. This fine-grained sandstone is very suitable for fine stonework and carving, but is not very weather-resistant. In the Netherlands, the name "sandstone" is used exclusively for pure sandstone (without lime) imported primarily from Northern Germany and, around 1900, also from Luxembourg and the surrounding area. The sandy limestones Balegemse Steen, Ledesteen, and Gobertange from Belgium (often called lime sandstone in Belgium), which are found in many medieval buildings, are usually not considered pure sandstones in the Netherlands. The common collective name for these types of stone is White Belgian Stone. In the Netherlands, sandstone surfaces in the east of Twente, near Winterswijk, and in Limburg. However, it is no longer quarried here. In the rest of the Netherlands, sufficient diagenesis has not yet occurred to yield sandstone. For four centuries, from 1450 to 1850, sandstone was primarily transported to the Netherlands from or via Bad Bentheim via the Overijsselse Vecht River. Cities such as Ommen and Zwolle benefited from this. Due to the high cost of transport, the stone was primarily used in important buildings. The facades of the Royal Palace in Amsterdam, for example, are constructed of Obernkirchener and Bentheimer sandstone. The invention of the train brought many exotic stone types onto the market. This marked the end of the heyday of the Bentheim Gold trade. Sandstone is still mined on a relatively small scale in and around Bentheim, particularly in Gildehaus; the quarry near Obernkirchen is operated on a much larger scale.
Arches National Park is famous for its many impressive rock formations and balancing rocks, such as the Courthouse Towers, Windows Section, Fiery Furnace, Devil's Garden, Klondike Bluffs, and Balanced Rock. There are more than 2,000 documented natural arches, including Landscape Arch, Double Arch, Double O Arch, and Delicate Arch. The smallest arches have a gap of barely one meter, while the distance between the supports of the largest arch (Landscape Arch) is 88.4 meters. In 1991, a section of Landscape Arch, measuring 20 meters by 3.66 meters by 1.33 meters, broke off. A witness filmed this. Walking under or on the arch is now prohibited. In 2005, the Wall Arch collapsed. In the north of the park lies an area called Devil's Garden. An 11-kilometer-long hiking trail leads to several arches. The arches were formed by a combination of wind and water erosion, ice, tectonic activity, and an unstable salt subsurface. On a clear day, it's hard to imagine that such primeval forces have been at work here for hundreds of millions of years. The history of the arches begins about 300 million years ago. Back then, the entire area was flooded several times. When the water evaporated or the climate became drier, salt was left behind. This salt accumulated, forming layers several hundred meters thick in some places. This salt layer was later covered with remnants of floods and winds. This sand slowly deformed into rock, sometimes more than a kilometer thick. Salt is unstable under pressure. The salt bed could not withstand the pressure of the overlying layers, deforming and creating vertical cracks in the rock layer above. In winter, ice formed in these cracks, expanding and causing the rock to crumble. The loosened rocks were carried away by the wind. During wetter periods, rain fell in the area, eroding the cracks as water flowed through them. Erosion is still ongoing and will eventually cause all the arches and rock formations to disappear. The process accelerated when the Colorado Plateau was pushed up between ten and five million years ago. The water eroded the cracks so deeply that it reached the underlying salt. When this salt was washed away, two valleys were formed in the area.
