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[theme topic] Oceanic Intraplate Volcanoes

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ltiansio 发表于 2011-1-6 10:07:43 | 显示全部楼层 |阅读模式
Oceanic Intraplate Volcanoes

It is widely accepted that most of the magmatic activities responsible for the construction of the oceanic crust takes place along ocean and back-arc spreading centers. However, intraplate magmatism, represented by volcanoes that form prominent linear island and seamount chains (e.g. Hawaii Island Chain) as well as those that occur individually (e.g. near-ridge seamounts on the EPR flanks) or form aseismic ridges (e.g. the Cocos and Carnegie aseismic ridges in the eastern Pacific) in a variety of tectonic settings, is also a significant source of crustal materials.

Understanding the structure, evolution, as well as origin of these oceanic intraplate volcanoes are not only important in geological sciences, but also in other fields. For example, in biological sciences,  seamounts can form a base for micro and macrobiological organisms; active volcanoes can support hydrothermal vent communities. On the other hand, the coral reefs can have a great effect on the seamounts' morphology where the reef grows while the volcano is subsiding, generating reefs or coral caps entirely submerged volcanoes. (ps: the discussion of seamounts are partly referred from J. Konter, 2007, Ph.D. thesis, SIO/UCSD).

So welcome to join in the discussion about oceanic intraplate volcanoes.
 楼主| ltiansio 发表于 2011-1-6 10:10:02 | 显示全部楼层
Some thought about the questions from

"weiciyixing"

请您从地质专业的角度解释下seamount、ocean island、ocean plateau
的特征,以及他们的成因,和构造位置。多谢了哈,我知道seamount是指那些没有露出洋面的海山,顶部有碳酸盐岩帽,并且存在生物礁,那么海山的下面是没有陆壳的物质吧?ocean plateau是指那种介于陆壳和洋壳之间的那种基底,而属于那种洋底平台的那种?ocean island是与热点有关么?那么夏威夷那么没有露出洋面的是称作seamount还是ocean plateau呢?同时夏威夷又是hot spot成因的,那么是不是又是ocean island呢?这三者的岩石组合有哪些特征呢?
 楼主| ltiansio 发表于 2011-1-6 10:11:37 | 显示全部楼层
本帖最后由 ltiansio 于 2011-1-6 12:28 编辑

回复 2# ltiansio

1. Seamounts are submarine mountains that are typically formed as active volcanoes, which later turn dormant and finally become extinct. Seamounts do not reach to the sea level, and thus are NOT islands.

2.  An oceanic plateau (also submarine plateau) is a large, relatively flat submarine region that rises well above the level of the ambient seabed. While many oceanic plateaus are composed of continental crust, and often form a step interrupting the continental slope, some plateaus are undersea remnants of large igneous provinces. These were formed by the equivalent of continental flood basalts such as the Deccan Traps in India and the Snake River Plain in the Pacific Northwest of the United States.

Geologists believe that igneous oceanic plateaus may well represent a stage in the development of continental crust as they are generally less dense than oceanic crust while still being denser than normal continental crust.

(from http://en.wikipedia.org/wiki/Oceanic_plateau).
 楼主| ltiansio 发表于 2011-1-6 12:33:37 | 显示全部楼层
回复 2# ltiansio

The hot-spot model is one hypothesis of ocean island volcanism.
Another popular hypothesis is SUMA model (Meibom and Anderson, 2004).

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徐敏 发表于 2011-1-6 12:47:31 | 显示全部楼层
Nice job, thanks for sharing
xiaohu 发表于 2011-1-6 13:28:14 | 显示全部楼层
COOL!
田老师自问自答,讲了一节有趣的课,学习中... ...
 楼主| ltiansio 发表于 2011-1-6 14:01:22 | 显示全部楼层
回复 6# xiaohu

自己先给自己捧场,
欢迎大家一起来捧场,
SunZhen 发表于 2011-2-14 23:33:15 | 显示全部楼层
按照你的解释,大部分的洋底高原为陆壳或者说洋陆过渡壳特征,那么Ontong Java呢,是不是也是你说的这种情况?难道不是地幔柱成因的?
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