Talk:Boninite

Geology Mid‑importance

	Geology portal Talk:Boninite is part of WikiProject Geology, an attempt at creating a standardized, informative, comprehensive and easy-to-use geology resource. If you would like to participate, you can choose to edit this article, or visit the project page for more information.GeologyWikipedia:WikiProject GeologyTemplate:WikiProject GeologyGeology articles
Mid	This article has been rated as Mid-importance on the project's importance scale.

Volcanoes Low‑importance

	Volcanoes portal This article is within the scope of WikiProject Volcanoes, a collaborative effort to improve the coverage of volcanoes, volcanology, igneous petrology, and related subjects on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.VolcanoesWikipedia:WikiProject VolcanoesTemplate:WikiProject VolcanoesWikiProject Volcanoes articles
Low	This article has been rated as Low-importance on the project's importance scale.

New Data[edit]

this news report says undersea volcano eruption formed this type of material, and was first time ever seen formed, and that youngest example of it before this was at least 1 m.y.o. http://news.yahoo.com/s/ap/20091218/ap_on_sc/us_deep_sea_volcano;_ylt=AntlFFSxpHUnkma391OnUuOs0NUE;_ylu=X3oDMTNrb2ptazBhBGFzc2V0A2FwLzIwMDkxMjE4L3VzX2RlZXBfc2VhX3ZvbGNhbm8EY2NvZGUDbW9zdHBvcHVsYXIEY3BvcwMzBHBvcwMxMARwdANob21lX2Nva2UEc2VjA3luX3RvcF9zdG9yeQRzbGsDaW50aGlzaW1hZ2V0 —Preceding unsigned comment added by 68.226.23.206 (talk) 00:57, 18 December 2009 (UTC)[reply]

Comments[edit]

I'm not sure about the Sanukitoid link; sanukitoids are not a common term used in Australian literature, and it seems like they are basically high-Mg diorites at best, but, that aside, boninites are extrusive, not intrusive, and are actually fairly enriched at times in alkalis.

Boninites are associated exclusively with back arcs, and are typically envisaged as beng brewed-up from deleted peridotite mantle via the action of the volatile plme behind the subduction zone. They are a phenomenon of slab-drag initiated convection behind the subduction zone (or vice-versa, who cares, really about semantics), and attain high MgO contents due to the previous depletion in Fe, Ti, etc, and the addition of volatiles. Boninites from the Marrianas Back Arc Basin are typically quite hydrous.

Boninites are also, in the Gympie Terrane, associated with M-type granitoids which inherit their Ti-Zr ratios and are examples of slab roll-back causing a change from melting of fertile mantle to re-melting it and producing higher-MgO Ti-depleted rocks.

Um...and thats all I can remember this side of pawing through my notes!

Rolinator 11:06, 28 October 2006 (UTC)[reply]