Talk:Ophiolite

Stubbed

Stubbed this because: Need more links on the ophiolite complexes; need some thumbnail maps of the ophiolites as well as images, sections, etc.Rolinator 14:47, 26 January 2006 (UTC)

Note: The article was unstubbed by Bluebot (talk · contribs) in August 2006.

I have now reorganized the article into sections per WP:MOS, and revised it to remove first/second person speech. --Seattle Skier (talk) 18:01, 15 April 2007 (UTC)

Mechanisms of formation

The majority of SSZ ophiolites now appear to be regarded as the result of subduction rollback in the literature, in order to produce the local extension regieme in an overall compressive setting. No seperate topic on rollback itself, subduction section is in need of improvement as well, currently working on a new graphic for that one which might be upload in the next couple of weeks. Will try and update the ophiolite formation section once I've got to grips with the wiki style of writing. ClimberDave 13:47, 17 April 2007 (UTC)

Image

Is it worth adding another image? I dont think this image below is too great but it better shows the dyke/lava relationship MeanStreets "...Chorizo..." 12:34, 28 April 2007 (UTC)

Sheeted Dykes, cross cut by larger dykes, topped by pillow lavas

External links modified

Hello fellow Wikipedians,

I have just added archive links to one external link on Ophiolite. Please take a moment to review my edit. If necessary, add {{cbignore}} after the link to keep me from modifying it. Alternatively, you can add {{nobots|deny=InternetArchiveBot}} to keep me off the page altogether. I made the following changes:

• Added archive https://web.archive.org/20120417225654/http://www.environment.gov.au:80/heritage/places/world/macquarie/values.html to http://www.environment.gov.au/heritage/places/world/macquarie/values.html

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

Y An editor has reviewed this edit and fixed any errors that were found.

• If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
• If you found an error with any archives or the URLs themselves, you can fix them with this tool. — Gorthian (talk) 18:20, 28 April 2016 (UTC)

Cheers. —^{cyberbot II}_{Talk to my owner:Online} 14:08, 17 October 2015 (UTC)

External links modified

Hello fellow Wikipedians,

I have just added archive links to one external link on Ophiolite. Please take a moment to review my edit. If necessary, add {{cbignore}} after the link to keep me from modifying it. Alternatively, you can add {{nobots|deny=InternetArchiveBot}} to keep me off the page altogether. I made the following changes:

• Added archive http://web.archive.org/web/20160110175240/http://ofioliti.it/ to http://www.ofioliti.it

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at {{Sourcecheck}}).

N An editor has determined that the edit contains an error somewhere. Please follow the instructions below and mark the |checked= to true

• If you have discovered URLs which were erroneously considered dead by the bot, you can report them with this tool.
• If you found an error with any archives or the URLs themselves, you can fix them with this tool. — Gorthian (talk) 18:23, 28 April 2016 (UTC)

Cheers.—^{cyberbot II}_{Talk to my owner:Online} 03:41, 28 February 2016 (UTC)

Macquarie Island

@Mamayuco: You added {{dubious}} to the statement about Macquarie Island. I checked out the reference given—it turned out that the statement was a direct quote from the source, so I've removed the template (and added quote marks so it's not a copyright violation!). Please feel free to reword it if you feel it needs to be, but be sure to cite your sources. Cheers! — Gorthian (talk) 18:19, 28 April 2016 (UTC)

A credible scientific report is needed to support such extraordinary claims. A government promotion website can not be fully trusted when it comes to scientific details. Mamayuco (talk) 20:21, 17 July 2016 (UTC)

I found these statements in credible sources:

1. "Macquarie Island is unique, among islands of the major ocean basins, in being an exposure of oceanic crust." (Varne R., Brown A.V., Falloon T. (2000). "Macquarie Island: its geology and structural history, and the timing and tectonic setting of its N-MORB to E-MORB magmatism." In Dilek Y., Moores E., Elthon D.&, Nicolas A. (eds) Geological Society of America, Special Publication. Ophiolites and oceanic crust: new insights from field studies and the Ocean Drilling Program. 349. 301-320). Varne made similar claims in 1969, 1972, 1980, and 1988 publications.

2. "Macquarie Island must be one of the few places on Earth where it is possible to walk about relatively easily on a slice of ocean-floor material surrounded by thousands of kilometres of open ocean." (Selkirk, Patricia, et al. (1990). Subantarctic Macquarie Island: Environment and Biology Studies in Polar Research, Cambridge University Press, p. 56.)

3. "Macquarie Island is a unique island of great geological importance, because it is the only locality in the world where a complete section of young ocean crust formed at a spreading center is exposed above sea level." (Dijkstra A. (2009). "Macquarie, Geology." In Gillespie R. & Clague D. (Eds.), Encyclopedia of Islands 575-577. University of California Press.)

My question is, what are the geological characteristics that distinguish Macquarie Island from Saint Peter and Saint Paul Archipelago in the Atlantic? Goustien (talk) 19:40, 21 March 2017 (UTC)

Saint Peter and Saint Paul are formed of serpentinised mantle that was exhumed at the seabed. The exact mechanism is not clear, although it may be related to deeply penetrating water causing serpentinisation of mantle peridotites, followed by the diapiric rise of this relatively low density and low strength material. In contrast, Macquarie Island is composed entirely of crustal materials including all layers of "standard" oceanic crust, from the sediments on top to the ultramafic cumulates at the base. The question as to whether the uplifted oceanic crust on Macquarie Island is an ophiolite, would depend on the definition used. Based on our opening sentence it fits the bill and has certainly been referred to in that way in the literature. Mikenorton (talk) 19:35, 22 March 2017 (UTC)

Alpine ophiolites

The recent removal of the longstanding uncited sections about, amongst other things, ophiolites in the alps got me thinking. I've recently been working on passive margins using the models of Gianreto Manatschal and his colleagues, who base a lot of their understanding of magma-poor passive margins on exposures from the Alps. These Alpine ophiolites are unusual (see e.g. Manatschal & Müntener 2009) so at least the first of the deleted paragraphs doesn't look that far off the mark. I'm not suggesting putting the deleted text back, just that we should probably have a section on the Alpine ophiolites and their interpretation. Mikenorton (talk) 15:56, 9 March 2018 (UTC)

Mikenorton, I deleted the content because it thought of two benefits: the article would gain credibility by having all content sourced and it will be easier to write with citations from zero than finding appropiate citations for each of these claims. As far as I know the ophiolite thing is tricky. It requires some research into literature. Is Alpine ophiolites still a valid or common category? —Lappspira (talk) 17:11, 9 March 2018 (UTC)

It does require some looking into and your right that it's generally easier to start from sources rather than try to make them fit the text that exists. My understanding is that the Alpine ophiolites are unusual, lacking in the upper layers of the "standard" ophiolite model. This is explained by them being dominated by mantle rocks exhumed at the non-volcanic margins of the so-called "Ligurian Tethys", but sources are as ever the key. Mikenorton (talk) 17:43, 9 March 2018 (UTC)