阅读JJ夏威岛链之我见

heavennancy

我看了夏威夷岛链的JJ，觉得巨难，于是找了背景资料，以前的人的帖子里也有，拿出来分享之，欢迎讨论

这个是维基百科里对于夏威夷岛链和国王海底山脉的解释，我觉得挺靠谱的。详细的请点下面的连接。我就不说了，主要是关于有一题有疑问。我觉得板块漂移说没戏了，现在流行的是hotspot理论，筒子们有何高见啊

http://en.wikipedia.org/wiki/Hawaiian%E2%80%93Emperor_seamount_chain

主要是关于有一题有疑问。我觉得板块漂移说没戏了，现在流行的是hotspot理论

所以那题岛链indicate什么，答案应该是由一个hotspot生成，而不是motion of ... plates

筒子们有何高见啊，考过的NN们也帮忙确认下吧，感激不尽啊     In 1963, geologist John Tuzo Wilson hypothesized the origins of the Hawaiian-Emperor seamount chain, explaining that they were created by a hotspot of volcanic activity that was essentially stationary as the Pacific tectonic plate drifted in a northwesterly direction, leaving a trail of increasingly eroded volcanic islands and seamounts in its wake. An otherwise inexplicable kink in the chain would mark a shift in the movement of the Pacific plate some 47 million years ago, from a northward to a more northwesterly direction, and the kink has been presented in geology texts as an example of how a tectonic plate can shift direction comparatively suddenly.

    Recent research shows that the hotspot itself may have moved with time. Some evidence comes from analysis of the orientation of the ancient magnetic field preserved by magnetite in ancient lava flows sampled at four seamounts (Tarduno et al.
, 2003): this evidence from paleomagnetism shows a more complex relationship than the commonly accepted view of a stationary hotspot. If the hotspot had remained above a fixed mantle plume during the past 80 million years, the latitude as recorded by the orientation of the ancient magnetic field preserved by magnetite should be constant for each sample and should also signify original cooling at the same latitude as the current Big Island of Hawaii. Comparisons with the traces of other hotspots also test if the Hawaiian-Emperor bend records a change in plate motion. Tarduno et al. (2009) have summarized evidence that the bend in the seamount chain may be caused by circulation patterns in the flowing solid mantle (mantle "wind") rather than a change in plate motion.

eling820

这篇我也研究了，同意你的观点，版块漂移错，hotspot会动对！

xz328

第一段几乎是原文的第一段。但是后面的这个就不是了。原文一共有4段。我记得在gwd上还是哪里做到过的。我有印象。

heavennancy

GWD7-Q22 to Q25   这篇关于火山形成原因的文章里后面部分有提到hotspot，请问NN是这个吗

另外，这篇的争议题说the chain of island indicates 不知NN选了哪个啊

1、夏威夷岛和帝王火山链是由同一个hotspot形成的；

2、显示了an ancient movement of the plate



    Earth’s surface consists of rigid plates that are constantly shifting and jostling one another.  late movements are the surface expressions of motions in the mantle—the thick shell of rock that lies between Earth’s crust and its metallic core.  Although the hot rock of the mantle is a solid, under the tremendous pressure of the crust and overlying rock of the mantle, it flows like a viscous liquid.  The mantle’s motions, analogous to those in a pot of boiling water, cool the mantle by carrying hot material to the surface and returning cooler material to the depths.  When the edge of one plate bends under another and its cooler material is consumed in the mantle, volcanic activity occurs as molten lava rises from the downgoing plate and erupts through the overlying one.

     Most volcanoes occur at plate boundaries.  However, certain “misplaced” volcanoes far from plate edges result from a second, independent mechanism that cools the deep interior of Earth.  Because of its proximity to Earth’s core, the rock at the base of the mantle is much hotter than rock in the upper mantle.  The hotter the mantle rock is, the less it resists flowing.  Reservoirs of this hot rock collect in the base of the mantle.  When a reservoir is sufficiently large, a sphere of this hot rock forces its way up through the upper mantle to Earth’s surface, creating a broad bulge in the topography.  The “mantle plume” thus formed, once established, continues to channel hot material from the mantle base until the reservoir is emptied. The surface mark of an established plume is a hot spot—an isolated region of volcanoes and uplifted terrain located far from the edge of a surface plate.  Because the source of a hot spot remains fixed while a surface plate moves over it, over a long period of time an active plume creates a chain of volcanoes or volcanic islands, a track marking the position of the plume relative to the moving plate.  The natural history of the Hawaiian island chain clearly shows the movement of the Pacific plate over a fixed plume.