Foldlic clūt
| Þis geƿrit hæfþ ƿordcƿide on Nīƿenglisce. |
Lāmlic clūt is dǣl þǣre Eorðan hrūsan (oþþe stānþōðres). Se oferblica þǣre Eorðan stendeþ on seofon micelum lāmlicum clūtum and manigum ōðrum lǣssum.
The plates are around 100 km (60 miles) thick and consist of two principal types of material: oceanic crust (also called sima) and continental crust (sial). Under both lies a relatively plastic layer of the Earth's mantle called the asthenosphere, which is in constant motion. This is in turn underlaid by a solid layer of mantle.
The composition of the two types of crust differs markedly. Oceanic crust consists largely of basaltic rocks, while the continental crust consists principally of lower density granitic rocks rich in aluminium and silica. The two types of crust also differ in thickness, with continental crusts considerably thicker than oceanic.
The churning of the asthenosphere carries the plates along in a process known as continental drift, which is explained by the theory of plate tectonics. Interaction between the plates creates mountains and volcanoes, as well as giving rise to earthquakes and other geological phenomena.
Þā gemǣru þāra clūta ne acordaþ mid þǣm gemǣrum þāra ƿorulddǣla. For instance, the North American Plate covers not only Norþ America ac ēac Grēneland, far eastern Siberia and Norðiapan.
Þæs þe is geƿiten, is sēo Eorðe se āna planēta in þǣre Sunnlican Endebyrdnesse tō hæbbenne foldlice clūtas, þēah þe man sægde þæt Mars mihton geāgen in þǣre forþgeƿitenan tīde, ǣr þǣm þe sēo planētanhrūse frēas on stæle.
Sēo ēac
[adihtan | adiht fruman]Ūtanƿearde bendas
[adihtan | adiht fruman]- Bird, P. (2003) An updated digital model of plate boundaries Archived 2007-12-13 at the Wayback Machine also available as a large (13 mb) PDF file [1] Archived 2003-08-06 at the Wayback Machine
- Landcarte eorþclūta Archived 2017-01-12 at the Wayback Machine