The Earth’s crust is constantly evolving. Over the millions of years, the movement of the tectonic plates have shaped the patterns of the oceans and continents, and laid the foundations for all the world’s amazing landscapes. The inside of the earth is protected by thick layers of molten mantle rock and by thin and solid outer layer of the crust. Molten rock rises from the mantle and bursts through into a dark underwater world, where it cools rapidly to form hard rock.
Such are these unusual landscapes which have evolved due to these seismic movements of the earth crust and are now the best tourist attractions of the world.
The Devil’s watchtower, Extinct volcano, USA, Wyoming
The Devil’s watchtower, the United States first national monument is a masterpiece of nature surging up from the plains of Wyoming cattle county. This is an excellent place from which we can view five different states- Wyoming, Nebraska, Montana, North Dakota, and South Dakota.
This huge structure that looks like a mass of columns clustered together, is in fact the core of an extinct volcano. Fifty million years ago, this rock seen today, was molten basalt lava in the pipe of an active volcano, and was surrounded by the sloping layers of ash that formed the cone. The simplest explanation is that Devils Tower is a stock—a small indiscreet body formed by magma which cooled underground and was later exposed by erosion. Geologist think that the tower is formed of Phonolite porphyry which is an igneous rock meaning it was formed on the cooling of magma or lava. And the cooling of magma condensed into columns. The molten basalt is rich in iron, which gives it a warm, rust-red coating, and the lichen that cover its surface adds further color. All in all, the size and symmetry, and the changing colors as the sunlight plays over it, make the Devils Tower one of the most stunning natural wonder of the world. But even this natural beauty has a legendary tale on the existence of this tower. The Cheyenne Indians name it as “Bad God’s tower” and the other native American people, the Kiowa, had their own explanation for its existence. A legend tells of seven little girls running from a wild bear. The girls jumped on to a low rock that started to grow higher and higher as the angry bear clawed at it, leaving sharp groove marks behind. The bear finally died of exhaustion and the girls were immortalized in the heavens as the seven stars of the Pleiades cluster.
Coral reefs- South Pacific Ocean
The Pacific Ocean has isolated and uninhabited coral islands, so exotic that these locations have been subject of many a fantasy and films. These tranquil corals exist in the coral-built islets of Bora Bora in the South Pacific Ocean.
How are these atolls formed and what are these atolls? Atolls are an underlying delicate ecosystem. These atolls or corals grow taking nutrients and oxygen from the ocean. More oxygen is generated by algae. Rock fragments and soils build up on these coral reefs to form a circle of new islands. Beneath these islands lie extinct volcanoes.
The coral first appears as a reef surrounding the cone of a volcano, but movements in the heart of the Earth cause the volcano to sink. The coral continues to grow so that the top of the reef stays in sunlight and above the surface of the water. Gradually, a circular lagoon appears in the center of the reef and fills it with coral sand. The lower parts of the reef and the deeper layers of the coral sand harden to form a strong limestone base, supporting the living coral above- until, eventually, the crown of the volcano is completely submerged and engulfed in limestone. The reef then continues to grow creating a circular atoll that encircles a shallow lagoon of coral sand. This is how these beautiful, scenic coral islands amidst the ocean came into being.
The Olgas- Monstrous domes and Cupolas, Australia
The Olgas are monstrous domes found in the Australian deserts. They appear to be enormous haystacks that lean against each other. The Australian aborigines call these beautiful landforms as “Kata Tjuta” or “many heads”. The first non-Aboriginal person to see Kata Tjuta was the explorer Ernest Giles, who spotted the domes in 1872. He named the highest peak Mount Olga, after Queen Olga of Württemberg (a kingdom in Germany at the time). The nickname of ‘The Olgas’ was most likely developed when the area was opened up to tourists in the 1950s.
Mount Olga, 3509 ft. high, is a part of a group of about 30 dome-shaped peaks living west of Ayers Rock (Uluru) in Australia’s Northern Territory. The Olgas are eroded remains of a long-gone mountain range that was deposited in the ancient sea. Sand and mud fell to the bottom and covered the seabed, including these fans. There the water separated the material into layers of pebbles and boulders which finally became cemented together by finer sand. The sandy fan became sandstone (Uluru) while the rocky fan became conglomerate rock (Kata Tjuta).
400 million years ago, the sea disappeared. Rocks folded and tilted as the earth’s tectonic plates shifted. Kata Tjuta tilted slightly and Uluru tilted 90 degrees.
Kata Tjuta is made from a conglomerate of pebbles and boulders cemented by sand and mud. Most of the pieces are granite and basalt, which give the conglomerate a plum-pudding effect.
These magnificent rock formations are a lot bigger than they appear – like icebergs, most of their mass is below the surface. Uluru and Kata Tjuta are only the tips of huge rock slabs that continue underground for up to 6 km!
The Aboriginals have known about them for some 40000 years and have used them as sources of fresh water and as places for hunting and shelter. Some of the caves beneath the mountains are decorated with cave paintings that depict events from folklore. One story tells that if tribal laws are broken, a serpent Wanampi will send strong gusts of wind through the gorges between the peaks to remind the people of their duties.
The rocks offer visitors a constantly changing array of color as the sun moves overhead and brightens the luxurious vegetation in deep clefts between the domes.