Helen's Reef

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Helens Rf̣ east of Rockall
Large area of ​​Rockall

Helen's Reef (English for:. Helens Reef ) is a shoal (submarine Aufragung), two kilometers east of the rocky island of Rockall . At low tide , the reef is typically six feet (six feet ) below the surface of the water; When the tide is very low and / or the waves are strong, a small, rounded rock is sometimes visible in the wave troughs of Helen's Reef. Otherwise, the shoal, which is approximately 3.60 meters (12 feet ) below sea level during high tide , can usually be identified above water by breaking waves. Depending on the water level and weather conditions, such waves can occur in an area up to 30 meters wide; only in calm weather and easterly winds they can only be seen at longer intervals.

The reef is part of the Rockall Plateau, a microcontinent west of the Hebrides . It does not consist of rocks that would be typical of the oceanic crust , but of material from the continental crust . Various rock samples from the reef show that it is an olivine-rich gabbro , the age of which has been dated to about 81 million years. The rock is very similar to younger gabbros from the Paleogene , such as those found on the Isle of Skye or St. Kilda , so that the Cretaceous age has been questioned. Another dating of a basalt from the Rosemary Bank (Rockall Plateau) showed an Upper Cretaceous age (71 to 69 million years, or possibly even a little older), which in this case is biostratigraphically secured by interim sediments .

A strong negative magnetic anomaly was found in the shallow area ; it is probably caused by locally high contents of ferromagnetic minerals in the rock.

Danger to shipping and origin of the name

For centuries, Helen's Reef has posed a serious threat to shipping. It has been repeatedly described as "very dangerous" (1848) or "probably the greatest danger" of all maritime obstacles in the area (1960).

The first known human "contact" may have occurred in 1686 when a ship was wrecked here or at nearby Rockall; the survivors were able to escape to St. Kilda (Scotland).

The shoal got its name in 1824, when the Brigantine Helen from Dundee (according to other information: Helen of Dundee ) drove to the previously unknown reef on April 19, 1824 under her captain Thomas Erskine on the way to Montréal (Canada) in a haze leaked; The crew and passengers tried to rescue the Helen by pumping for 13 hours before they had to give up her. After a dinghy was destroyed while being launched, only the 12 man crew and one passenger in two other boats were able to save themselves and were salvaged by the Bark Flora (allegedly on the way from Gdansk to Liverpool) under Captain Baker. 16 passengers - including 7 women and children - died.

According to some information, a ship under Captain Osborn from Workington ( Cumbria ) may have entered the area of ​​the reef as early as 1806 and escaped only with difficulty; a report from 1825 suggests, however, that the reef was shallows in the southeast (not: northeast) of Rockall.

The Scottish Geographical Magazine suspected decades later it was "not unlikely that at least some of the puzzling cases of lost well equipped vessels, as reported annually by the Atlantic Ocean, associated with this dangerous, invisible reefs [including the Helen's Reef] in conjunction . ”In spite of the known dangers, neither Helen's Reef nor the nearby rock Rockall had been provided with beacons, bells or barrels up to this point ; the Trinity House - the beacon management for England - shared on request with, it was never adopted, Rockall lies under the jurisdiction of ( jurisdiction ) of the English Beacon Management.

Rockall remained unlit until at least 1955; a beacon was only erected at Helen's Reef around 1973.

Individual evidence

  1. ↑ (1907 ?!). Transactions of the South African Philosophical Society, Volume 16 (p. 24). Royal Society of South Africa (Engl.)
  2. ↑ John Alexander Harvie-Brown, Thomas E. Buckley, William Anderson Smith, R. Foster Heddle (1888). A vertebrate fauna of the outer Hebrides. Volume 2 of Vertebrate fauna of Scotland (p. C [ sic! ]). D. Douglas
    Nicholas Coit Flemming (Ed.) (1973). Science diving international: proceedings of the 3rd symposium of the Scientific Committee of the Confederation Mondiale des Activités Subaquatiques, 8th – 9th October, 1973: held in London during the 3rd World Congress of CMAS (p. 207). British Sub Aqua Club
    (1955 ?!). The Listener, Volume 54 (p. 497). British Broadcasting Corporation
  3. ^ DG Roberts, NC Flemming, RK Harrison, PE Binns, and NJ Snelling: Helen's Reef: a microgabbroic intrusion in the Rockall intrusive center, Rockall Bank . Marine Geology, Volume 16, 1974, pp. M21-M30.
  4. ^ JD Ritchie and K. Hitchen: Early Paleogene offshore igneous activity to the northwest of the UK and its relationship to the North Atlantic Igneous Province . Geological Society London Special Publication 101, 1996, pp. 63-78.
  5. ↑ Andrew C. Morton, Ken Hitchen, J. Derek Ritchie, Nicolette M. Hine, Martin Whitehouse, and Sam G. Carter: Late Cretaceous basalts from Rosemary Bank, Northern Rockall Trough. Journal of the Geological Society, 152 (6): 947-952, London 1995 doi : 10.1144 / GSL.JGS.1995.152.01.11
  6. ^ DG Roberts: A new Tertiary volcanic center on the Rockall Bank, Eastern North Atlantic Ocean . Nature, Vol. 223, pp. 819-820, 1969.
  7. ^ William C. Redfield // or: James Tasker [ Master of the Grace Darling ] (1848). Memoir of the dangers and ice of the North Atlantic Ocean (p. 1). (Collected by George William Blunt), E. & GW Blunt
  8. ↑ (1960 ?!). The Nautical Magazine. A Magazine for Those Interested in Ships and the Sea. Volumes 183-184 (p. 156).
  9. ↑ (1950). Bird notes. Volumes 24-25. Royal Society for the Protection of Birds
  10. ↑ Steven Sora (2004). The lost colony of the Templars: Verrazano's secret mission to America (p. 134). Inner Traditions / Bear & Company
  11. ↑ isb. Origin of name: Nicholas Coit Flemming (Ed.) (1973). Science diving international: proceedings of the 3rd symposium of the Scientific Committee of the Confederation Mondiale des Activités Subaquatiques, 8th – 9th October, 1973: held in London during the 3rd World Congress of CMAS (p. 207). British Sub Aqua Club
    Details: John Purdy (1825). Memoir, descriptive and explanatory. to accompany the new chart of the Atlantic ocean and comprising instructions, general and particular, for the navigation of that sea (p. 242). RH Laurie
  12. ↑ (1898?) Scottish geographical magazine, Volume 14 (p. 399). Royal Scottish Geographical Society
  13. ^ John Purdy (1825). Memoir, descriptive and explanatory. to accompany the new chart of the Atlantic ocean and comprising instructions, general and particular, for the navigation of that sea (p. 242). RH Laurie
  14. ↑ On the whole, it seems not unprobable that some, at least, of the mysterious disappearances of well-found vessels which are reported annually from the Atlantic are connected with these dangerous hidden reefs. (1898?) Scottish geographical magazine, Volume 14 (p. 399). Royal Scottish Geographical Society
  15. ^ Scottish geographical magazine, Volume 14
  16. ↑ (1955 ?!). The Listener, Volume 54 (p. 497). British Broadcasting Corporation
    Mine and quarry, Volume 2. Ashire Publishing

Coordinates: 57 ° 36 ′ 5 ″  N , 13 ° 39 ′ 29 ″  W.