Troodos Ophiolite

The geochemical evidence implies that the Troodos ophiolite has come from mantle that has already been depleted, with extraction of mid ocean ridge basalt, but then subsequently enriched in certain trace elements as well as water.

The Troodos is a unique ophiolite in terms of observing hydrothermal alteration, because it has not been metamorphosed to a high extent or deformed extensively.

The fact that the same kinds of alteration can be seen in modern axes implies the same processes happened at the Troodos, even though it was formed in a supra-subduction zone.

The presence of alteration in all of the extrusive levels but the very highest imply a succession of numerous hydrothermal convection cells active during eruption.

In the early 1970s it began to be widely accepted that the ophiolite represented sea-floor spreading, and subsequently that the Troodos showed geochemical signatures like that of arc volcanics.

[citation needed] This last fact was first pushed by Akiho Miyashiro in 1973 who challenged the common conception of Troodos Ophiolite and proposed an island arc origin for it.

From subsequent studies of other ophiolites it has been found that these generally have a similar geochemical signature, and so it is inferred that most are supra-subduction zone related.

In Tethyan passive margins gravity sliding over accretionary terranes via low angle thrust faults was proposed.

In the supra-subduction zone, spreading is not controlled like in mid-ocean ridge settings, as the extension is mainly facilitated by slab rollback that creates space independently of the availability of magma.