Superficial deposits

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Superficial deposits (or surficial deposits [1] ) refer to geological deposits typically of Quaternary age (less than 2.6 million years old) for the Earth. These geologically recent unconsolidated sediments may include stream channel and floodplain deposits, beach sands, talus gravels and glacial drift and moraine. All pre-Quaternary deposits are referred to as bedrock. [2]

Contents

Types and history

There are several types of superficial deposit, including raised beaches and brickearth. These were formed in periods of climate change during the ice ages. The raised beaches were generally formed during periods of higher sea level, when ice sheets were at a minimum, and the sand and shingle deposits can be seen in many low cliffs. The brickearth is originally a wind-blown dust deposited under extremely cold, dry conditions but much has been re-deposited by flood water and mixed with flints. [2]

Superficial deposits were originally recorded only onshore and around the coast where they were laid down by various natural processes such as action by ice, water and wind. More recently offshore deposits have been mapped and may be separate sea-bed sediments.

Most of these superficial deposits are unconsolidated sediments such as gravel, sand, silt and clay, and onshore they form relatively thin, often discontinuous patches. Almost all of these deposits were formerly classified on the basis of mode of origin with names such as, 'glacial deposits', 'river terrace deposits' or 'blown sand'; or on their composition such as 'peat'.

Geology databases contain information on the properties of superficial deposits. Geological survey houses these Geology databases. This information can be used for a number of different purposes in farming and forestry, including avoiding erosion, assessing growing conditions, gauging risks in terms of nutrient leaching and release of toxic substances, planning site preparation, road construction, felling and extraction operations, judging accessibility etc. [3] [4] [5]

Geological Survey

Each country and is some countries each state or province has an organization with a superficial deposits database. Some of the geological survey are:

See also

Related Research Articles

<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">Moraine</span> Glacially formed accumulation of debris

A moraine is any accumulation of unconsolidated debris, sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a glacier or ice sheet. It may consist of partly rounded particles ranging in size from boulders down to gravel and sand, in a groundmass of finely-divided clayey material sometimes called glacial flour. Lateral moraines are those formed at the side of the ice flow, and terminal moraines were formed at the foot, marking the maximum advance of the glacier. Other types of moraine include ground moraines and medial moraines.

<span class="mw-page-title-main">Loess</span> Sediment of accumulated wind-blown dust

A loess is a clastic, predominantly silt-sized sediment that is formed by the accumulation of wind-blown dust. Ten percent of Earth's land area is covered by loesses or similar deposits.

<span class="mw-page-title-main">Oak Ridges Moraine</span> Glacial till landform above Lake Ontario, Canada

The Oak Ridges Moraine is an ecologically important geological landform in the Mixedwood Plains of south-central Ontario, Canada. The moraine covers a geographic area of 1,900 square kilometres (730 sq mi) between Caledon and Rice Lake, near Peterborough. One of the most significant landforms in southern Ontario, the moraine gets its name from the rolling hills and river valleys extending 160 km (99 mi) east from the Niagara Escarpment to Rice Lake, formed 12,000 years ago by advancing and retreating glaciers during the last glaciation period. Below the approximately 200 metre thick glacial derived sediments of the moraine lies thick bedrock successions of Precambrian rocks and up to 200 metres of Ordovician aged rock, capped by a regional unconformity of erosion and non-deposition to the Quaternary period. Rivers and lakes scatter the landscape and are important for creating habitat for the rich diversity of species of animals, trees and shrubbery. These are also the supply of fresh water to aquifers in the moraine through complex subterranean connections. Construction development nearby, and with expansion of communities around the moraine in need of potable water, it is a contested site in Ontario, since it stands in the path of major urban development. Conservation of the moraine is thus an important step for keeping aquifers in a safe drinkable condition while also protecting the natural ecosystems surrounding and within the moraine. This region has been subject to multiple decades of scientific research to study the origins of formation, and how early communities used the land. A larger focus currently is how to source potable water without removing the aquifer entirely.

Parent material is the underlying geological material in which soil horizons form. Soils typically inherit a great deal of structure and minerals from their parent material, and, as such, are often classified based upon their contents of consolidated or unconsolidated mineral material that has undergone some degree of physical or chemical weathering and the mode by which the materials were most recently transported.

<span class="mw-page-title-main">Drift (geology)</span> Material of glacial origin

In geology, drift is a name for all sediment transported by a glacier and deposited directly by or from the ice, or by glacial meltwater. Drift is often subdivided into unstratified drift that forms moraines and stratified drift that accumulates as stratified and sorted sediments in the form of outwash plains, eskers, kames, varves, and so forth. The term drift clay is a synonym for boulder clay. Both are archaic terms for glacial tills with a fine-grained matrix.

<span class="mw-page-title-main">Diluvium</span> Deposits created as a result of catastrophic outbursts of Pleistocene giant glacier-dammed lakes

Diluvium is an archaic term applied during the 1800s to widespread surficial deposits of sediments that could not be explained by the historic action of rivers and seas. Diluvium was initially argued to have been deposited by the action of extraordinary floods of vast extent, specifically the Noachian Flood.

The Perth Basin is a thick, elongated sedimentary basin in Western Australia. It lies beneath the Swan Coastal Plain west of the Darling Scarp, representing the western limit of the much older Yilgarn Craton, and extends further west offshore. Cities and towns including Perth, Busselton, Bunbury, Mandurah and Geraldton are built over the Perth Basin.

The Fylde is a coastal plain in western Lancashire, England. It is roughly a 13-mile-long (21-kilometre) square-shaped peninsula, bounded by Morecambe Bay to the north, the Ribble estuary to the south, the Irish Sea to the west, and the foot of the Bowland hills to the east which approximates to a section of the M6 motorway and West Coast Main Line.

<span class="mw-page-title-main">Brickearth</span>

Brickearth is a term originally used to describe superficial windblown deposits found in southern England. The term has been employed in English-speaking regions to describe similar deposits.

<span class="mw-page-title-main">Shingle beach</span> Beach which is armoured with pebbles or small- to medium-sized cobbles

A shingle beach, also known as either a cobble beach or gravel beach, is a commonly narrow beach that is composed of coarse, loose, well-rounded, and waterworn gravel, called shingle. The gravel (shingle) typically consists of smooth, spheroidal to flattened, pebbles, cobbles, and sometimes small boulders, generally in the 20 to 200 millimetres size range. Shingle beaches typically have a steep slope on both their landward and seaward sides. Shingle beaches form in wave-dominated locations where resistant bedrock cliffs provide gravel-sized rock debris. They are also found in high latitudes and temperate shores where the erosion of Quaternary glacial deposits provide gravel-size rock fragments. This term is most widely used in Great Britain.

A buried valley is an ancient river or stream valley that has been filled with glacial or unconsolidated sediment. This sediment is made up of predominantly gravel and sand, with some silt and clay. These types of sediments can often store and transmit large amounts of groundwater and act as a local aquifer.

<span class="mw-page-title-main">Lake Albany</span> Prehistoric proglacial lake

Glacial Lake Albany was a prehistoric North American proglacial lake that formed during the end of the Wisconsinan glaciation. It existed between 15,000 and 12,600 years ago and was created when meltwater from a retreating glacier, along with water from rivers such as the Iromohawk, became ice dammed in the Hudson Valley. Organic materials in Lake Albany deposits have been carbon dated to approximately 11,700 years ago. The lake spanned approximately 160 miles (260 km) from present-day Poughkeepsie to Glens Falls.

<span class="mw-page-title-main">Geology of Massachusetts</span>

The geology of Massachusetts includes numerous units of volcanic, intrusive igneous, metamorphic and sedimentary rocks formed within the last 1.2 billion years. The oldest formations are gneiss rocks in the Berkshires, which were metamorphosed from older rocks during the Proterozoic Grenville orogeny as the proto-North American continent Laurentia collided against proto-South America. Throughout the Paleozoic, overlapping the rapid diversification of multi-cellular life, a series of six island arcs collided with the Laurentian continental margin. Also termed continental terranes, these sections of continental rock typically formed offshore or onshore of the proto-African continent Gondwana and in many cases had experienced volcanic events and faulting before joining the Laurentian continent. These sequential collisions metamorphosed new rocks from sediments, created uplands and faults and resulted in widespread volcanic activity. Simultaneously, the collisions raised the Appalachian Mountains to the height of the current day Himalayas.

The geology of Essex in southeast England largely consists of Cenozoic marine sediments from the Palaeogene and Neogene periods overlain by a suite of superficial deposits of Quaternary age.

The geology of Lincolnshire in eastern England largely consists of an easterly dipping succession of Mesozoic age sedimentary rocks, obscured across large parts of the county by unconsolidated deposits dating from the last few hundred thousand years of the present Quaternary Period.

The geology of Norfolk in eastern England largely consists of late Mesozoic and Cenozoic sedimentary rocks of marine origin covered by an extensive spread of unconsolidated recent deposits.

The Albion Glacigenic Group is a Quaternary lithostratigraphic group present in those parts of Great Britain which lie north of the southern limit of Anglian glaciation, but south of the Devensian glacial limit, and also includes deposits in the Isle of Man and offshore areas. It consists of a wide range of unconsolidated superficial deposits including till, sands, gravels, silts and clay of glacial, glaciofluvial, glaciolacustrine and glaciomarine origin. Its upper boundary is the present day ground surface or unconformable contact with units of the Caledonia Glacigenic Group, the Britannia Catchments Group or the British Coastal Deposits Group. It was previously known as the South Britain Glacigenic Group or Older Drift

<span class="mw-page-title-main">Geology of Rhode Island</span>

The geology of Rhode Island is based on nearly one billion year old igneous crystalline basement rocks formed as part of the microcontinent Avalonia that collided with the supercontinent Gondwana. The region experienced substantial folding associated with its landlocked position during the Alleghanian orogeny mountain building event. The region accumulated sedimentary rocks, including small deposits of coal. The region was covered with thick Atlantic Coastal Plain sediments, with the erosion of the Appalachians and the creation of the Atlantic Ocean throughout the past 200 million years. These surficial sediments and soils were substantially reworked by the Pleistocene glaciations. The state's geology is part of the broader geology of New England.

The bedrock geology of Ceredigion in west Wales consists wholly of a considerable thickness of Ordovician and Silurian age sedimentary rocks of marine origin. Unconsolidated deposits of Quaternary age include a widespread cover of glacial till, valley floor alluvium and scattered peat deposits in both upland and lowland settings.

References

  1. Jackson, Julia A., ed. (1997). "superficial deposit". Glossary of geology (Fourth ed.). Alexandria, Virginia: American Geological Institute. ISBN   0922152349.
  2. 1 2 "BGS Geology themes".
  3. 1 2 "NZL GNS 1:250K Geology (3rd edition) - data.govt.nz - discover and use data". catalogue.data.govt.nz.
  4. 1 2 "View All Details". app.companiesoffice.govt.nz. Retrieved 2021-10-12.
  5. 1 2 "Surficial geology | U.S. Geological Survey". www.usgs.gov.
  6. British Geological Survey, arcgis.com
  7. "Rock Classification Scheme - Vol 4 - Superficial".
  8. "Sidan finns inte". www.sgu.se.
  9. "Forsiden for Norges geologiske undersøkelse (NGU) | NGU". www.ngu.no.
  10. Government of Canada, Natural Resources Canada (December 7, 2015). "GEOSCAN Search Results: Fastlink". geoscan.nrcan.gc.ca.
  11. "2.10 Surficial Mineral Systems | Geoscience Australia". www.ga.gov.au.
  12. Geological Survey of India, gsi.gov.in
  13. "China Geological Survey". en.cgs.gov.cn.