Uluru / Ayers Rock, Northern Territory, Australia

Uluru / Ayers Rock is a massive rock structure located in Northern Territory, Australia. Consisting of red sandstone that is relatively resistant to weathering, Uluru / Ayers Rock prominently rises 348 meters above the surrounding lowlands. The structure has likely been formed by sediment deposition in alluvial fans associated with mountain uplift during the late Neoproterozoic to early Cambrian (~ 550 million years ago), followed by tilting in the Paleozoic (~ 400 million years ago). Subsequent erosion of the surrounding rocks and the formation of iron oxides further shaped Uluru / Ayers Rock into its present state as a majestic red mountain.

Information source: Uluru-Kata Tjuta National Park Service

Image: Uluru / Ayers Rock at sunset in Northern Territory, Australia. Credit: Weyf, Wikimedia Commons.

The Twelve Apostles, Victoria, Australia

The Twelve Apostles is a group of rock structures along the Great Ocean Road in Victoria, Australia. These limestone pillars were formed by wave erosion of caves and arches along the mainland cliffs. Eight pillars of the Twelve Apostles still remain, but there were only nine pillars in total.

Information source: Twelve Apostles Marine National Park Service

Image: The Twelve Apostles along the Great Ocean Road in Victoria, Australia. Source: Mike Lehmann, Wikimedia Commons.

The Wave, Arizona, USA

The Wave is a rock formation in the Colorado Plateau of Arizona in the United States that was formed by erosion of the Jurassic Navajo Sandstone. It is known for its many undulating structures and contains large sets of cross bedding in aeolian sandstones, which reflect the migration of sand dunes and ripples across an ancient desert environment. The cyclically alternating laminae seen in the Wave result from periodic changes in the prevailing wind directions at the time of deposition.

Information source: Vermillion Cliffs National Monument Service

Image: Cross-bedded aeolian sandstones of the Wave in the Colorado Plateau of Arizona, USA. Source: Sehara, Wikimedia Commons.

Monument Valley, Arizona and Utah, USA

Monument Valley is located on the border between Arizona and Utah in the United States, where it is part of the Colorado Plateau. It is characterized by various rock structures consisting of red siltstones and sandstones of Permian-Triassic age, including the massive sandstone buttes for which the valley is known best. The red color of the rocks in Monument Valley is the result of extensive siltstone weathering and the associated formation of iron oxides, but the overlying sandstone layers are more resistant. Under the scorching heat of the desert sun, a few well-adapted bushes and shrubs prevail.

Information source: Monument Valley Navajo Tribal Park Service

Image: Monument Valley buttes in the Colorado Plateau between Arizona and Utah, USA. Source: Luca Galuzzi, Wikimedia Commons.

Bryce Canyon, Utah, USA

Bryce Canyon is a canyon system found in Utah in the United States that has been formed by headward erosion of the Colorado Plateau at the origin of rivers and streams. It is known for its many spire-like structures called hoodoos, which generally consist of thick layers of relatively soft and easily eroded rocks, such as mudstones, overlain by thin layers of harder and more resistant rocks, such as sandstones or limestones. Hoodoos attain their characteristic shapes because this protective cover of resistant rocks shields the underlying layers from the elements, while the surrounding rocks are subjected to frost weathering and river erosion.

Information source: Bryce Canyon National Park Service

Image: Thor’s Hammer and other hoodoos in Bryce Canyon in the Colorado Plateau of Utah, USA. Source: Luca Galuzzi, Wikimedia Commons.

Antelope Canyon, Arizona, USA

Antelope Canyon is a slot canyon in the Colorado Plateau of Arizona in the United States. It consists of two different sections, the Upper Antelope Canyon and the Lower Antelope Canyon. Both have been formed by erosion of the Navajo Sandstone, mainly by flash floods associated with heavy rain. Antelope Canyon is well known for beams of light illuminating flowing shapes in the rocks.

Information source: Antelope Canyon National Park Service

Image: Walls of Antelope Canyon in the Colorado Plateau of Arizona, USA. Source: Luca Galuzzi, Wikimedia Commons.

Grand Canyon, Arizona, USA

The Grand Canyon is a colossal canyon system in Arizona in the United States that has been eroded by the Colorado River and its tributaries during the uplift of the Colorado Plateau. The Grand Canyon is 446 km long and up to 29 km wide, and reaches a depth of over 1.6 km at its deepest point. In this giant scar across the land, almost 2 billion years of geological history are revealed in well-preserved stratigraphic sections, ranging from the Precambrian Vishnu Schist at the base of the Inner Gorge to the Permian Kaibab Limestone at the Rim.

Information source: Grand Canyon National Park Service

Image: The Grand Canyon and Horn Creek Rapid in the Colorado Plateau of Arizona, USA. Source: Luca Galuzzi, Wikimedia Commons.