Purple sand

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Purple Sand patterns on Pfeiffer Beach, CA Purple Sand patterns on Pfeiffer Beach, Big Sur CA July 8th, 2016.jpg
Purple Sand patterns on Pfeiffer Beach, CA

Purple beaches are a phenomenon caused by the presence of a large amounts of almandine-pyrope garnet. [1] [2] [3] or other purple minerals like manganese [4] or rose quartz that have accumulated in the local sediment. These purple beaches are primarily found in the western Canadian Shield region of Canada or the Northern Continental United States; often in proximity to a major river systems with coarse sediment, a glacial sediment source, or input from glacial or para-glacial sediment. [5] Purple sand can also be caused by purple paint mixing with the quartz in sand.

Contents

Causes

Purple sand on Pfeiffer Beach. Rosino - 7359707792.jpg
Purple sand on Pfeiffer Beach.

Surficial garnet deposits primarily originate from the glacial erosion of plutons, with the majority from the glacial erosion of the Canadian Shield caused by ice flow during retreat of the Laurentide Ice Sheet. [6] These beaches often have stripes of various colors or shades caused by the waves sorting the minerals by density and therefore color. As a wave comes ashore it pushes less-dense minerals higher up the beach while denser minerals settle first. [7] The relatively low density of the garnet causes it to rise to the top of the sand giving the beaches their unique color. [8]

Purple Sand Beaches

Related Research Articles

<span class="mw-page-title-main">Canadian Shield</span> Geographic and geologic area of North America

The Canadian Shield, also called the Laurentian Plateau, is a geologic shield, a large area of exposed Precambrian igneous and high-grade metamorphic rocks. It forms the North American Craton, the ancient geologic core of the North American continent. Glaciation has left the area with only a thin layer of soil, through which exposures of igneous bedrock resulting from its long volcanic history are frequently visible. As a deep, common, joined bedrock region in eastern and central Canada, the shield stretches north from the Great Lakes to the Arctic Ocean, covering over half of Canada and most of Greenland; it also extends south into the northern reaches of the United States.

<span class="mw-page-title-main">Beach</span> Area of loose particles at the edge of the sea or other body of water

A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shells or coralline algae. Sediments settle in different densities and structures, depending on the local wave action and weather, creating different textures, colors and gradients or layers of material.

<span class="mw-page-title-main">Drumlin</span> Elongated hill formed by glacial action

A drumlin, from the Irish word droimnín, first recorded in 1833, in the classical sense is an elongated hill in the shape of an inverted spoon or half-buried egg formed by glacial ice acting on underlying unconsolidated till or ground moraine. Assemblages of drumlins are referred to as fields or swarms; they can create a landscape which is often described as having a 'basket of eggs topography'.

<span class="mw-page-title-main">Sediment</span> Particulate solid matter that is deposited on the surface of land

Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone through lithification.

<span class="mw-page-title-main">Silt</span> Classification of soil or sediment

Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil or as sediment mixed in suspension with water. Silt usually has a floury feel when dry, and lacks plasticity when wet. Silt can also be felt by the tongue as granular when placed on the front teeth.

<span class="mw-page-title-main">Placer deposit</span> Accumulation of valuable minerals formed by gravity separation

In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation from a specific source rock during sedimentary processes. The name is from the Spanish word placer, meaning "alluvial sand". Placer mining is an important source of gold, and was the main technique used in the early years of many gold rushes, including the California Gold Rush. Types of placer deposits include alluvium, eluvium, beach placers, aeolian placers and paleo-placers.

<span class="mw-page-title-main">Clearwater River (Saskatchewan)</span> River in Western Canada

The Clearwater River is located in the Canadian provinces of Saskatchewan and Alberta. It rises in the northern forest region of north-western Saskatchewan and joins the Athabasca River in north-eastern Alberta. It was part of an important trade route during the fur trade era and has been designated as a Canadian Heritage River.

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<span class="mw-page-title-main">Lake Souris</span> Former lake in Souris River

The Glacial Lake Souris occupied the basin of the Souris River from the most southern portion of this river's loop in North Dakota to its elbow in Manitoba, where it turned sharply northward and passed through the Tiger Hills. The length of Lake Souris was about 170 miles, from latitude 48° to latitude 50°35', and its maximum width, north of Turtle Mountain, was nearly 70 miles. It was situated near the far southeast corner of the large glacial Lake Agassiz, separated from it by another small glacial body, Glacial Lake Hind.

<span class="mw-page-title-main">Taiga Shield Ecozone (CEC)</span>

The Taiga Shield Ecozone, as defined by the Commission for Environmental Cooperation (CEC), is an ecozone which stretches across Canada's subarctic region. Some regions exhibit exposed Precambrian bedrock of the Canadian Shield, the oldest of the world's geological formations. The world's oldest rocks, dating to four billion years, are found in the Canadian Shield north of Great Slave Lake.

<span class="mw-page-title-main">Candle Lake (Saskatchewan)</span> Lake in Saskatchewan, Canada

Candle Lake is a reservoir in the central part of the Canadian province of Saskatchewan in the boreal forest, approximately 80 kilometres (50 mi) north-east of Prince Albert. A dam completed in 1979 at the southern end of the lake regulates water levels; several small creeks feed into the lake and Torch River flows out of the lake at the dam. Candle Lake Provincial Park surrounds most of the lake and the resort village of Candle Lake is at the southern end.

<span class="mw-page-title-main">Sand</span> Granular material composed of finely divided rock and mineral particles

Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass.

<span class="mw-page-title-main">Geology of Saskatchewan</span> Geologic features of the Canadian province

The geology of Saskatchewan can be divided into two main geological regions, the Precambrian Canadian Shield and the Phanerozoic Western Canadian Sedimentary Basin. Within the Precambrian shield exists the Athabasca sedimentary basin. Meteorite impacts have altered the natural geological formation processes. The prairies were most recently affected by glacial events in the Quaternary period.

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<span class="mw-page-title-main">Geology of Finland</span> Overview of the geology of Finland

The geology of Finland is made up of a mix of geologically very young and very old materials. Common rock types are orthogneiss, granite, metavolcanics and metasedimentary rocks. On top of these lies a widespread thin layer of unconsolidated deposits formed in connection to the Quaternary ice ages, for example eskers, till and marine clay. The topographic relief is rather subdued because mountain massifs were worn down to a peneplain long ago.

<span class="mw-page-title-main">Oak Lake (Manitoba)</span> Lake in Manitoba, Canada

Oak Lake is a lake in the south-western part of the Canadian province of Manitoba in a region called Westman. Oak Lake is a kettle lake and is an aquifer supplier for numerous nearby residential areas and farms. The lake is in the RM of Sifton and sits at an elevation of 426 metres above sea level. Provincial Road 254 provides access to the lake.

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Douglas Provincial Park is a provincial park in the Canadian province of Saskatchewan. Established in 1973, it is named after Tommy Douglas, the seventh premier of Saskatchewan and father of Canada's first single-payer, universal health care programme. The park is located along the Gordon McKenzie Arm of Lake Diefenbaker and at the Qu'Appelle River Dam, which is the source of the Qu'Appelle River. The closest community is Elbow and access to the park is from Highway 19.

References

  1. "Why is the Sand Purple at Plum Island Beach?". JEOL USA. Retrieved 16 November 2021.
  2. Sepp, Siim (16 May 2013). Pfeiffer Beach sand . Retrieved 16 November 2021.
  3. Coastal Environments NE Massachusetts and New Hampshire Field Trip Eastern Section (PDF), Society of Economic Paleontologists and Mineralogists, 9–11 May 1969, p. 215–313
  4. "Clearwater Lake Provincial Park Management Plan" (PDF). Manitoba Conservation and Water Stewardship Parks and Natural Areas Branch. January 2013. Retrieved 18 Nov 2021.
  5. Hein, Christopher J.; et al. (1 Jan 2014). "Evolution of para-glacial coasts in response to changes in fluvial sediment supply". London Geological Society Special Publications. 388 (15): 270. Bibcode:2014GSLSP.388..247H. doi:10.1144/SP388.15. S2CID   129662471 . Retrieved 19 November 2021.
  6. Eccles, D.R. (2008). Geological Evaluation of Garnet-Rich Beaches in East-Central Alberta, with Emphasis on Industrial Mineral and Diamondiferous Kimberlite Potential (PDF). Energy Resources Conservation Board. Retrieved 23 November 2021.
  7. Turner, Bob; Quat, Marianne; Debicki, Ruth; Thurston, Phil (2015). Natural Resources Canada and Ontario Geological Survey 2015. Parry Sound: Canadian Shield and glacier-sculpted gneiss in cottage country; GeoTours Northern Ontario series (PDF). Retrieved 23 November 2021.
  8. Brown, Jay (9 February 2016). "6 Natural Wonders You Must Experience in Saskatchewan" . Retrieved 18 November 2021.
  9. MacDonald, Ryan (11 February 2020). "Canada's little-known geological wonder". BBC. Retrieved 18 November 2021.
  10. "Some of the best beaches in Canada!". Tourism Saskatchewan. Retrieved 18 November 2021.