Natural arch - online puzzles

Natural arch

A natural arch, natural bridge, or (less commonly) rock arch is a natural landform where an arch has formed with an opening underneath. Natural arches commonly form where inland cliffs, coastal cliffs, fins or stacks are subject to erosion from the sea, rivers or weathering (subaerial processes).

Most natural arches are formed from narrow fins and sea stacks composed of sandstone or limestone with steep, often vertical, cliff faces. The formations become narrower due to erosion over geologic time scales. The softer rock stratum erodes away creating rock shelters, or alcoves, on opposite sides of the formation beneath the relatively harder stratum, or caprock, above it. The alcoves erode further into the formation eventually meeting underneath the harder caprock layer, thus creating an arch. The erosional processes exploit weaknesses in the softer rock layers making cracks larger and removing material more quickly than the caprock; however, the caprock itself continues to erode after an arch has formed, which will ultimately lead to collapse.

The choice between bridge and arch is somewhat arbitrary. The Natural Arch and Bridge Society identifies a bridge as a subtype of arch that is primarily water-formed. By contrast, the Dictionary of Geological Terms defines a natural bridge as a "natural arch that spans a valley of erosion."The largest natural arch, by a significant margin, is the Xianren Bridge in China, with a span of 122 ± 5 meters (400 ± 15 ft).

Rocks online puzzleCliff online puzzleIgloo online puzzleCliff online puzzleDianas grotto Sevastopol puzzle online from photoGolden buddhist pavilion in wild cave, Thailand puzzle online from photoMalta puzzle online from photoNew Zealand puzzle online from photofjord puzzle online from photoRed Arch road tunnel puzzle online from photoView from the cave puzzle online from photoCLUE : FENOMENA AIR MATA BIRU & KEPALA KUDA online puzzleCoyote Canyon online puzzleNatures Window, Western Australia puzzle online from photoSea Enters Cave Way puzzle online from photoUnique rock formations in Damaraland Namibia online puzzleSea Wonder online puzzleFalse Kiva online puzzleSun Peeks Through puzzle online from photothe arch puzzle online from photo
Copyright 2025 www.epuzzle.info All rights reserved.