Tidal glaciers

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The Columbia Glacier in Alaska, the world's best-explored tidal glacier

When tidewater glaciers (including marine glaciers ) are glacier called that end in the sea and by the so-called calving icebergs produce. The term does not include glaciers that calve in freshwater . If these are to be included, the term “calving glaciers” should be used. The extent of the tides does not play a role, at least for the conceptual classification. Today, tidal glaciers only exist at higher latitudes beyond the 45th parallel . They are found in Alaska , the Canadian Arctic, Greenland , Svalbard , Novaya Zemlya and Antarctica, as well as a few in Patagonia . Many tidal glaciers are outlet glaciers from an ice cap or ice sheet .

Calving in the sea is a major ablation process; around 70 percent of the water that glaciers and ice sheets around the world give off to the oceans ends up in the sea in this way. Most tidal glaciers outside the polar regions end with a steep ice cliff that rests on the ocean floor. But especially in the polar regions, the glacier can penetrate far enough into the water that the end of the glacier floats up and forms a floating tongue or an ice shelf .

In tidal glaciers, a cyclical process has been observed that has no direct connection with climatic conditions, in which the length of the glacier changes periodically. In this process, known as the Tidewater Glacier Cycle , it plays a role on the one hand that the calving speed increases with increasing water depth, and on the other hand that the glacier reduces the water depth due to the accumulation of moraines on the seabed.

literature

  • Andreas Vieli: Tidewater Glaciers. In: Vijay P. Singh, Pratap Singh, Umesh K. Haritashya (Eds.): Encyclopedia of Snow, Ice and Glaciers. Springer, Dordrecht 2011, ISBN 978-90-481-2641-5 , pages 1175-1179
  • Douglas I. Benn, Charles R. Warren, Ruth H. Mottram: Calving processes and the dynamics of calving glaciers. In: Earth Science Reviews 82, 2007, pp. 143-179.
  • Roger LeB. Hooke: Principles of Glacier Mechanics. Second edition. Cambridge University Press, Cambridge 2005, ISBN 0-521-83609-3

Individual evidence

  1. ↑ Benn et al .: Calving processes and the dynamics of calving glaciers. Page 145f, see literature
  2. ^ Hooke: Principles of Glacier Mechanics. Page 6, see literature
  3. ↑ a b c Andereas Vieli: Tidewater Glaciers. See literature