To install click the Add extension button. That's it.

The source code for the WIKI 2 extension is being checked by specialists of the Mozilla Foundation, Google, and Apple. You could also do it yourself at any point in time.

4,5
Kelly Slayton
Congratulations on this excellent venture… what a great idea!
Alexander Grigorievskiy
I use WIKI 2 every day and almost forgot how the original Wikipedia looks like.
Live Statistics
English Articles
Improved in 24 Hours
Added in 24 Hours
What we do. Every page goes through several hundred of perfecting techniques; in live mode. Quite the same Wikipedia. Just better.
.
Leo
Newton
Brights
Milds

Great Estuarine Group

From Wikipedia, the free encyclopedia

Great Estuarine Group
Stratigraphic range: Bajocian-Bathonian 170–164 Ma
Sandstones of the Elgol Sandstone Formation, exposed in the cliff behind Elgol school
TypeGroup
Unit ofHebrides Basin
Sub-units
UnderliesStaffin Bay Formation or Skye Lava Group
OverliesBearreraig Sandstone Formation
Thicknesscirca 33–289 m (108–948 ft)
Lithology
PrimaryMudstone
OtherSandstone
Location
RegionScotland
Country United Kingdom
ExtentInner Hebrides

The Great Estuarine Group is a sequence of Middle Jurassic sedimentary rocks deposited in the Inner Hebrides of Scotland. The sedimentary sequence was originally named the 'Great Estuarine Series' by geologist John Wesley Judd in 1878. [1] Sedimentary outcrops occur on Skye, Raasay, Eigg and Muck.[2] It comprises a series of shales, clays, silts, mudstones, and sandstones deposited in two drainage basins: the Inner Hebrides basin and the Sea of the Hebrides basin.[3] The sediments are equivalent in age to the Inferior and Great Oolite Groups found in southern England.

The Group overlies the Garantiana Mudstone of the 'Bearreraig Sandstone Formation' and is itself overlain by rocks of the 'Skye Lava Group', erupted during the Palaeocene.[1]

The lowermost (and hence oldest) unit of the Great Estuarine Group is the 'Cullaidh Shale Formation'. Overlying this is the 'Elgol Sandstone Formation', the type locality of which is to be found at the village of Elgol on Skye. These sandstones are interpreted as being deltaic in origin. Above the sandstone is the 'Lealt Shale Formation', a unit in which fossils of creatures which lived in brackish lagoons abound. These include mussels, sharks and plesiosaurs. The discovery of the first plesiosaur was made in 1844 by the geologist Hugh Miller. The 'Kildonnan Member' of the Lealt Shale Formation contains stromatolites and various microfossils such as dinoflagellates and acritarchs. The succeeding 'Lonfearn Member' consist of shales and thin shelly and oolitic limestones with conchostracan fossils. It has also yielded dinosaur footprints.

At the next stratigraphic level the 'Valtos Sandstone Formation' represents a further series of deltaic sandstones. Large calcareous concretions commonly occur within this formation. They are post-depositional in origin with individual nodules reaching more than a metre in diameter and cutting across the bedding. The 'Duntulm Formation' succeeds the Valtos Formation and is in turn succeeded by the 'Kilmaluag Formation', and then by the youngest unit of the Great Estuarine Group, the 'Skudiburgh Formation'.[4]

YouTube Encyclopedic

  • 1/3
    Views:
    107 562
    731 662
    4 845
  • What's An Estuary? Now You Know.
  • Food Chains ,Food Webs,Energy Pyramid in Ecosystems-Video for Kids
  • Rookery Bay National Estuarine Research Reserve 2013

Transcription

[music] When you mix the fresh water of the river, with the salt water of the sea, something wonderful happens. As if by magic, a life supporting habitat is created for hundreds of species of fish, birds, and mammals. It’s called an estuary. This protected body of water, often partially enclosed by reefs, barrier islands, or fingers of land, is distinct from all other places on earth. In fact it’s irreplaceable. For you see estuaries are the most productive ecosystems on earth, containing more life per square inch than the richest farmland or the deepest forest. There are over 100 estuaries in the United States, which are home to tens of thousands of fish, birds, mammals, unique plant communities, and over one hundred and ten million people. 70 percent of the entire United States population visits an estuary every year. People in wildlife love estuaries for their many beautiful and diverse habitats, including sandy beaches, fresh and salt water marshes, rocky shores, shellfish beds, mangrove forests, river deltas, sea grass meadows, and wooded swamps. These special places are the most popular on earth, yet not many of their inhabitants or visitors even know what they are called. Many of us in fact boat, swim, surf, and fish in an estuary without even knowing it’s an estuary. Estuaries lead the world in life support, critically serving as places to live, eat, and reproduce for tens of thousands of birds, fish, and mammals. They are ideal spots for migratory birds to drop in and enjoy some R&R and act as 5-star hotels for fish and mammals. Estuaries are known as the nurseries of the sea, as their sheltered waters are perfect for spawning. Thousands of marine animals depend on estuaries at some point in their life. They are truly the real Magic Kingdom. Estuaries also house unique plant communities. Salt marsh grasses and other estuarine plants help to prevent pollution, erosion, floods, and stabilize our shoreline. Ahhh … all that and beautiful too. In addition to creating a food web for the multitudes of fish, birds, and mammals, estuaries also provide habitat for 75 percent of America’s commercial fish catch and 80 to 90 percent of the recreational fish catch, for our human dining pleasure. Estuaries are where the environment truly is the economy. Commercial and recreational fishing, boating, and tourism provide for more than 28 million jobs. And fishing alone generates 111 billion dollars each year. More than 10 billion dollars is spent on recreational boating products and services. Coastal recreation and tourism generate 12 billion dollars annually. Estuaries are also important to our quality of life and health for reasons other than our economy. They often serve as the heart of the community. A gathering place for community life, traditions, and celebrations. They are invaluable laboratories for scientists and students. They are the inspiration for artists and nature lovers.   Estuaries are national treasures. Vital places whose well being affects our health and the vitality of our community and economy.   They are irreplaceable and must be managed carefully for the mutual benefit of all who enjoy and depend on them.   We are unfortunately loving our estuaries to death. Half the American population now lives in coastal areas and coastal counties continue to grow at a rate three times faster than inland counties. As our love for these special places called estuaries grows, so does their human population and thus, the demands imposed on these beautiful natural resources. Without proper management we could kill the very goose that lays the golden egg.   It is the mission of the National Estuary Program to restore and protect America’s nationally significant estuaries. [music]

See also

References

  1. ^ a b "BGS Lexicon of Named Rock Units - Result Details".
  2. ^ Harris, J. P.; Hudson, J. D. (August 1980). "Lithostratigraphy of the Great Estuarine Group (Middle Jurassic), Inner Hebrides". Scottish Journal of Geology. 16 (2–3): 231–250. doi:10.1144/sjg16020231. ISSN 0036-9276.
  3. ^ Harris, J. P. (January 1992). "Mid-Jurassic lagoonal delta systems in the Hebridean basins: thickness and facies distribution patterns of potential reservoir sandbodies". Geological Society, London, Special Publications. 62 (1): 111–144. doi:10.1144/GSL.SP.1992.062.01.11. ISSN 0305-8719.
  4. ^ p337-342, Trewin, N.H. (ed) 2002 ‘’The Geology of Scotland’’. The Geological Society, London
This page was last edited on 28 March 2024, at 17:38
Basis of this page is in Wikipedia. Text is available under the CC BY-SA 3.0 Unported License. Non-text media are available under their specified licenses. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. WIKI 2 is an independent company and has no affiliation with Wikimedia Foundation.