Pancake Rocks | |
|---|---|
 Looking south across Pancake Rocks | |
  Pancake Rocks | |
| Coordinates: 42°06′50″S171°19′34″E / 42.11389°S 171.32611°E | |
| Location | Punakaiki |
| Offshore water bodies | Tasman Sea |
| Age | Oligocene |
| Topo map | Topo50 map BS19 |
The Pancake Rocks and Blowholes are a coastal rock formation at Punakaiki on the West Coast of the South Island of New Zealand. They are a popular visitor attraction.
The Pancake Rocks and Blowholes are located at Dolomite Point, immediately adjacent to the village of Punakaiki, in an area that is protected and forms part of the Paparoa National Park. [1]
The limestone of the Pancake Rocks has been uplifted and then eroded into the current landforms by a combination of two processes – karst erosion (a slow process where chemical erosion of the limestone occurs through the action of water flowing in joints and caverns), and coastal erosion (including the collapse of caverns).
The Pancake Rocks are a heavily eroded limestone formation where the sea bursts through several vertical blowholes during incoming swells, particularly at high tide. The limestone was formed in the Oligocene period (around 22–30 million years old), a period in the geological history of New Zealand where most of the continent of Zealandia was submerged beneath shallow seas. [2] The limestone rocks of the Punakaiki region began forming on the sea floor in warm coastal waters, offshore from a group of low-lying islands. There was a great profusion and diversity of marine organisms growing in these waters, and when these animals died, their shells settled on the sea floor along with small amounts of sand and mud eroded from nearby islands. Over millions of years, vast quantities of shell debris accumulated on the sea floor, eventually forming a thick deposit of nearly pure calcium carbonate. [3]
About 25 million years ago, at the beginning of the Miocene, there was a phase of upward movement of the Earth's crust (known as the Kaikoura Orogeny), that led to the formation of the Southern Alps. Large amounts of sand and mud were eroded from the emerging land and deposited on the sea floor, on top of the shell debris. Over the following 20 million years, as the uplift of the crust continued, the older shell debris became buried under a great thickness of accumulated sand and mud. The high pressures created by the new layers expelled water from the shelly sediment, and this gradually became cemented and lithified to form limestone rock. In the Pliocene, a few million years ago, the Kaikoura Orogeny led to slow folding and faulting of sedimentary layers in the Paparoa region, raising them above sea level. Following this uplift, erosion processes stripped away most of the sedimentary rocks which covered the region. However, at Punakaiki, a downwarping of the crust preserved much of the sedimentary layers. Where the limestone now appears at the surface at Dolomite Point, erosion has removed all the younger mudstones and sandstones. Subsequent erosion of the limestone headland has created the unusual karst landscape. [3]
The regular layering that can be observed in the Pancake Rocks results from a process called stylobedding. Under the influence of high pressure and compaction, small imperfections in the calcium carbonate that forms the limestone tend to aggregate in horizontal planes, in a process known as grain boundary diffusion. This leads to regular bands of stronger rock separated by weaker and more erodable mudstone rock. [2] Thousands of years of rain, wind and spray have mechanically weathered away the surface of the mudstone layers, leaving the limestone layers in relief. [3]
Uplift of the crust is continuing and its recent effects can be seen at Dolomite Point. The flat surface of the headland is in fact an old beach surface, formed at sea level 100,000 years ago and since uplifted by around 35 metres (115 ft). Patches of beach gravel and sand can be found on the headland. [3]
The blowholes at Dolomite Point, Punakaiki have been formed through combined processes of erosion. The action of waves, combined with karst erosion in joints and faults in the limestone rock, leads to the creation of caverns that become sea caves. When the sea cave erodes upwards and towards the land, it can create an opening to the surface. Incoming waves trap air in the sea cave and the air inside the cave becomes compressed, leading to the ejection of air and water upwards from the top of the blowhole. The activity level of the blowhole depends on factors like tide, sea conditions and the geometry of the caverns. The best conditions for viewing the blowholes are at high tide when there is a large incoming ocean swell. [2]
State Highway 6 is the only through-road on the West Coast, and a large number of visitors pass through Punakaiki. In 2017, it was estimated that there were 450,000 visitors, and many of these take the short walk to view the Pancake Rocks and Blowholes. [4] It has been claimed that the Pancake Rocks are the most photographed rock formations in New Zealand. [5]
The site is accessible by a number of walkways winding through the rock formations. Parts of these are wheelchair-accessible and others are carved into stairways up and down the rock faces. [6]
A cave or cavern is a natural void under the Earth's surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance underground. Caves which extend further underground than the opening is wide are called endogene caves.
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of sediments, ie. mineral or organic particles, at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus. The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies. Sedimentation may also occur as dissolved minerals precipitate from water solution.
Sedimentology encompasses the study of modern sediments such as sand, silt, and clay, and the processes that result in their formation, transport, deposition and diagenesis. Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary structures.
A stack or sea stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by wave erosion. Stacks are formed over time by wind and water, processes of coastal geomorphology. They are formed when part of a headland is eroded by hydraulic action, which is the force of the sea or water crashing against the rock. The force of the water weakens cracks in the headland, causing them to later collapse, forming free-standing stacks and even a small island. Without the constant presence of water, stacks also form when a natural arch collapses under gravity, due to sub-aerial processes like wind erosion. Erosion causes the arch to collapse, leaving the pillar of hard rock standing away from the coast—the stack. Eventually, erosion will cause the stack to collapse, leaving a stump. Stacks can provide important nesting locations for seabirds, and many are popular for rock climbing.
Landforms are categorized by characteristic physical attributes such as their creating process, shape, elevation, slope, orientation, rock exposure, and soil type.
The geology of Great Britain is renowned for its diversity. As a result of its eventful geological history, Great Britain shows a rich variety of landscapes across the constituent countries of England, Wales and Scotland. Rocks of almost all geological ages are represented at outcrop, from the Archaean onwards.
The geology of the Grand Canyon area includes one of the most complete and studied sequences of rock on Earth. The nearly 40 major sedimentary rock layers exposed in the Grand Canyon and in the Grand Canyon National Park area range in age from about 200 million to nearly 2 billion years old. Most were deposited in warm, shallow seas and near ancient, long-gone sea shores in western North America. Both marine and terrestrial sediments are represented, including lithified sand dunes from an extinct desert. There are at least 14 known unconformities in the geologic record found in the Grand Canyon.
The geology of the Zion and Kolob canyons area includes nine known exposed formations, all visible in Zion National Park in the U.S. state of Utah. Together, these formations represent about 150 million years of mostly Mesozoic-aged sedimentation in that part of North America. Part of a super-sequence of rock units called the Grand Staircase, the formations exposed in the Zion and Kolob area were deposited in several different environments that range from the warm shallow seas of the Kaibab and Moenkopi formations, streams and lakes of the Chinle, Moenave, and Kayenta formations to the large deserts of the Navajo and Temple Cap formations and dry near shore environments of the Carmel Formation.
The exposed geology of the Bryce Canyon area in Utah shows a record of deposition that covers the last part of the Cretaceous Period and the first half of the Cenozoic era in that part of North America. The ancient depositional environment of the region around what is now Bryce Canyon National Park varied from the warm shallow sea in which the Dakota Sandstone and the Tropic Shale were deposited to the cool streams and lakes that contributed sediment to the colorful Claron Formation that dominates the park's amphitheaters.
Paparoa National Park is on the west coast of the South Island of New Zealand. The park was established in 1987 and encompasses 430 km2 (170 sq mi). The park ranges from or near the coastline to the peaks of the Paparoa Range. A separate section of the park lies to the north and is centred at Ananui Creek. The park protects a limestone karst area. The park contains several caves, of which Metro Cave / Te Ananui Cave is a commercial tourist attraction. The majority of the park is forested with a wide variety of vegetation. The park was the site of the 1995 Cave Creek disaster where fourteen people died as a result of the collapse of a scenic viewing platform.
Punakaiki is a small village on the West Coast of the South Island of New Zealand. It is located between Westport and Greymouth on State Highway 6, the only through-road on the West Coast. Punakaiki is immediately adjacent to Paparoa National Park, and is also the access point for a popular visitor attraction, the Pancake Rocks and Blowholes.
The Delaware Basin is a geologic depositional and structural basin in West Texas and southern New Mexico, famous for holding large oil fields and for a fossilized reef exposed at the surface. Guadalupe Mountains National Park and Carlsbad Caverns National Park protect part of the basin. It is part of the larger Permian Basin, itself contained within the Mid-Continent oil province.
A sea cave, is also known as a littoral cave, a type of cave formed primarily by the wave action of the sea. The primary process involved is erosion. Sea caves are found throughout the world, actively forming along present coastlines and as relict sea caves on former coastlines. Some of the largest wave-cut caves in the world are found on the coast of Norway, but are now 100 feet or more above present sea level. These would still be classified as littoral caves. By contrast, in places like Thailand's Phang Nga Bay, solutionally formed caves in limestone have been flooded by the rising sea and are now subject to littoral erosion, representing a new phase of their enlargement.
The geology of England is mainly sedimentary. The youngest rocks are in the south east around London, progressing in age in a north westerly direction. The Tees–Exe line marks the division between younger, softer and low-lying rocks in the south east and the generally older and harder rocks of the north and west which give rise to higher relief in those regions. The geology of England is recognisable in the landscape of its counties, the building materials of its towns and its regional extractive industries.
Achilles Point is a rocky point on the headland at the eastern end of the small sandy beach named Ladies Bay, Auckland, New Zealand. The name 'Te Pane o Horoiwi' can also sometimes refer to the whole headland between St Heliers and Tamaki River estuary. Achilles Point is named after a ship called HMNZS Achilles (70) which defeated the German pocket battleship Admiral Graf Spee in 1939. The headland, from the point round to the Tamaki heads, was previously known as Te Pane o Horoiwi, named after Horoiwi who arrived in New Zealand on the Tainui canoe (waka).
The geology of Ohio formed beginning more than one billion years ago in the Proterozoic eon of the Precambrian. The igneous and metamorphic crystalline basement rock is poorly understood except through deep boreholes and does not outcrop at the surface. The basement rock is divided between the Grenville Province and Superior Province. When the Grenville Province crust collided with Proto-North America, it launched the Grenville orogeny, a major mountain building event. The Grenville mountains eroded, filling in rift basins and Ohio was flooded and periodically exposed as dry land throughout the Paleozoic. In addition to marine carbonates such as limestone and dolomite, large deposits of shale and sandstone formed as subsequent mountain building events such as the Taconic orogeny and Acadian orogeny led to additional sediment deposition. Ohio transitioned to dryland conditions in the Pennsylvanian, forming large coal swamps and the region has been dryland ever since. Until the Pleistocene glaciations erased these features, the landscape was cut with deep stream valleys, which scoured away hundreds of meters of rock leaving little trace of geologic history in the Mesozoic and Cenozoic.
The geology of Austria consists of Precambrian rocks and minerals together with younger marine sedimentary rocks uplifted by the Alpine orogeny.
The geology of Utah, in the western United States, includes rocks formed at the edge of the proto-North American continent during the Precambrian. A shallow marine sedimentary environment covered the region for much of the Paleozoic and Mesozoic, followed by dryland conditions, volcanism, and the formation of the basin and range terrain in the Cenozoic.
The geology of the State of New York is made up of ancient Precambrian crystalline basement rock, forming the Adirondack Mountains and the bedrock of much of the state. These rocks experienced numerous deformations during mountain building events and much of the region was flooded by shallow seas depositing thick sequences of sedimentary rock during the Paleozoic. Fewer rocks have deposited since the Mesozoic as several kilometers of rock have eroded into the continental shelf and Atlantic coastal plain, although volcanic and sedimentary rocks in the Newark Basin are a prominent fossil-bearing feature near New York City from the Mesozoic rifting of the supercontinent Pangea.
