Double island
Double island refers to two types of islands, namely the land mass separated by a waterway and a land mass connected by a land bridge .
Land mass separated by waterways
Two islands of almost the same size or at least the same shape are called double islands if there is only a relatively narrow natural water passage between the individual land masses.
Such double islands are often divided into north and south or west and east islands. Examples of this are the Russian island of Novaya Zemlya , or the Danish islands of Funen and Zealand .
Land masses connected by land bridge
A double island is also called an island that consists of two similarly sized parts that are connected by a land bridge ( isthmus ).
Such a form of a double island was formed by the German island of Helgoland up to about 300 years ago, together with the offshore island of Düne , with which it was connected via a land bridge ( called Woal ) that has now disappeared .
Further examples are the sub-Antarctic Heard Island with the striking Laurens Peninsula in the west, the South Sea island of Tahiti , consisting of Tahiti Nui and Tahiti Iti, and the Japanese island of Hachijō-jima . Such islands are often of volcanic origin, such as the Nicaraguan island of Ometepe , which essentially consists of two volcanoes that are connected by a narrow land bridge.
Some islands have grown together from five or more individual islands, such as the island of Hawaii , Isabela (Galápagos) or Long Islet in the Caroline Atoll .
Lewis and Harris is not an actual double island , since there is no isthmus between them, but the north and south parts, which are not clearly separated geographically (although Harris is differentiated by its mountainous nature), only have their own names and are treated as separate islands. Curiously, there is an isthmus between the north and south of Harris.
See also
Individual evidence
- ↑ Hugo Toeppen: The double island Nowaja Zemlya: history of their discovery. 1878
- ^ Carl Ritter, William Leonard Gage: Comparative Geography. 1865. (page 203)
- ^ Daniel Völter: General description of the earth. 1846. (Volume 1, page 9)
- ^ Johann Georg Kohl: The traffic and the settlement of the people in their dependency, 1841. (Page 349)
- ↑ Exotics on Heligoland ( Memento from August 7, 2008 in the Internet Archive )