Definition of ultrabasic in English:

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ultrabasic

Pronunciation: /ˌəltrəˈbāsik/

adjective

Geology
Relating to or denoting igneous rocks having a silica content less than 45 percent by weight, most of which are also ultramafic. Compare with ultramafic.
Example sentences
  • Major shear zones containing basic and ultrabasic igneous rocks are interpreted as suture zones.
  • This convergence gave rise to southward thrusting of the Yixieke forearc in Ordovician-Early Silurian time, which then led to obduction of the Buziwan ultrabasic rocks southward over the Kudi terrane.
  • On the other hand, the Kudi gneisses are imbricated with an ophiolitic slice south to Kudi, and overthrust by the Buziwan ultrabasic rocks.

For editors and proofreaders

Syllabification: ul·tra·ba·sic

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