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过渡区的研究是极其困难的与正常的岩石相比，在一段时间内它是反磁性区域。佛罗里达克莱门特国际大学的paleomagneticist Brad Clement 的研究（右页）。当发生地震（A），地震波，遵循不同的方向穿过地球内部的不同部分。当10年后（B）另一个地震再次击中同一个故障，地震波一致。1993年和2003年相比，当从两次地震穿过内核的P波和S波叠加两次地震之间的细微变化被视为（C），显示的波PKP（DF）穿行速度。 One of the benefits of having established a significant seismological network across the planet during the 20th century is the ability to track when an earthquake strikes twice. Curiously, the second time an earthquake hits the same exact fault, the speed of its waves traveling through the inner core are faster than they were the first time the earthquake struck. Not so for earthquake waves that pass only through the mantle or outer core. These have stayed exactly the same. Seismologists first took notice of this variation in earthquake wave propagation in the 1980s. They reported an increase in speed in waves traveling north–south through the inner core and hypothesized that the phenomena was the result of the way the iron in the inner core likely lined up north–south, parallel with Earth‘s axis of rotation. In the 1990s, seismologists reconsidered this model. They shifted the north–south axis of the inner core away from the Earth‘s axis of rotation and hypothesized that the inner core was spinning faster on its own axis of rotation than the rest of the planet. The observational data of seismic histories fit neatly with this new model. Careful observations of seismic waves into the 21st
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century confirmed a faster inner core.
20世纪整个地球建立了地震台网，好处之一便是能够跟踪两次地震袭击。奇怪的是，第二次地震发生同样的故障，其波穿过的内核心的速度比第一次地震时快。这样的地震波，仅仅通过地幔、外核。这些都保持完全的相同。地震学家在20世纪80年代，首先注意到了这种地震波的传播变化。他们报告说，在地震波通过内核南北极是速度增加，他们推测这可能是由于铁在内核南北极排列，并地轴旋转相平行所致。在20世纪90年代，地震学家重新考虑了这一模式。他们从地轴旋转速度推测内核南北极旋转速度，内核纺锤旋转速度比地球自转速度对比起宁静的行星来说。地震历史观测数据恰好符合这个新的模型。进入21世纪的地震波仔细观察确认了内核旋转更快。
Another curious aspect of the inner core is its role in reversing the Earth‘s magnetic field. The last time Earth‘s magnetic North Pole was located near the geographic South Pole was 780,000 years ago. As the planet and inner core spin, the outer core responds with turbulent eddies in the molten iron. Recently the magnetic field has been fading, becoming weaker in certain regions. This is dangerous for satellites traveling through these weak zones as the magnetic field protects the machinery from damaging high-energy particles. Geophysicists interpret the recent decline in the field as knots in the chaotic eddies of the liquid outer core. In the next 2,000 years, Earth may see its north–south dipole dissolve to a multi-pole with other magnetic ―north‖ poles of 90° inclination spouting momentarily in strange places like the equator before the planet switches to a south–north dipole for thousands or millions of years. Whether such multi-poles precede reversals remains a mystery. Currently the Earth is awash with small variations of such poles in the upper Northern and Southern Hemispheres, but the main magnetic ―north‖ and ―south‖ poles dominate the magnetic field. It is conceivable that the field may weaken and enter a transition period only to bounce back to normal.fully analyzed minute ocean sediment samples from transition zones and found the time period for the change took as little as 1,800 years to as long as 7,000 years. His report, ―Dependence on the duration of geomagnetic polarity reversals on site latitude,‖ appeared in Nature in April 2004. Paleontological evidence shows that life on Earth ignores such magnetic reversals, although migration patterns may change. The time the Earth takes to switch from a north-south to a south-north magnetic field happens quickly in geologic timescales, but it takes more than 40 to 140 generations in human timescales. Generations from now humans may have to build a compass that can operate with multipoles.
内核另一个令人好奇的方面，是它作用在扭曲地球磁场上。在78万年前，上一次地球磁场北极位于地理南极附近。地球和内芯旋转，“外核”对“内核”的铁水湍流涡旋响应。最近的磁场已经衰落，在某些地区变得越来越弱。卫星穿越这些薄弱区的磁场高能粒子是危险的对于保护机械损伤来说。地球物理学家解释最近在该领域液态外核在混沌漩涡里下降。在接下来的2000年里，可以看到地球北南–偶极溶解到其它磁性里，数千年或数百万年南北极成90度倒转，届时会有很多像赤道磁极一样陌生的地方。这种多级逆转在之前仍是一个谜。目前，地球在南、北两极充满了小的变化，但主要的磁性仍是“北”和“南”两极。可以想象的是，该领域可能削弱和进入一个过渡时期才恢复到正常。在全面分析了过渡区时间段的海洋沉积物样品后发现的变化的时间在很短的1800年到7000年之间。他在报告中说，纬度地磁极性倒转在2004年4月当地出现。古生物学证据表明，尽管，迁移模式会发生变化，但是地球上的生命忽略这样的磁场倒转。地球南北极倒转在地质时间尺
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度上是迅速发生的但对于人类来说，它超过40到140代人的时间。代现在人类有可能建造一个指南针，参与多极操作。
Hot spots—those mantle plumes that form island archipelagos such as Hawaii in the middle of tectonic plates, and keep Iceland growing in the same spot in the middle of the Mid-Atlantic spreading ridge—are still hot topics for Earth scientists. Do they sometimes move? Do they change size? Where do the plumes start, deep in the mantle near the core or higher up in the convection process? In July 2006, Japanese geophysicists introduced the term petit spots to explain tiny, young volcanoes on the old Pacific crust dipping into the trenches off Japan and Kuril islands. The team identified a small percentage of mantle melt mixed in with the asthenosphere in the baby volcanoes. They hypothesize the volcanoes formed when the higher lithosphere began to crack during subduction, allowing the asthenosphere and parts of the upper mantle to bleed through the crust. The hunt is now on for petit spots elsewhere subduction takes place. ―I‘d bet we will recognize ?petit spots‘ in the Mediterranean, where microplates are being stressed and subducted in strange geometries,‖ says Richard Cowen of the University of California at Davis.
热点地幔柱形成的岛如夏威夷板块中间的群岛，与冰岛同在大西洋中脊中的相同点成长，仍然是热点地球科学家。他们有时会移动吗？他们会改变规模吗？在哪里开始发生，在附近的对流过程的核心处或更深的地幔处？在2006年7月，日本地球物理学家介绍，哪些微型年轻火山长期浸入形成太平洋的日本海沟和千岛群岛。研究小组发现一小部分火山熔岩发源于融融的地幔与岩刘圈。他们假设，较高的岩石圈俯冲过程中出现火山，使软流圈及上地幔的部分岩浆通过地壳。他们寻找其他微型俯冲发生的地点。加州大学戴维斯分校的李察考恩说“我打赌我们会在地中海发现微型俯冲，在微板块中的作用形成奇怪的形状”。
Michael Wysession of Washington University in St. Louis, Missouri, found what he calls ―wet spots.‖ Beneath eastern Asia the lower mantle is acting like a wet sponge, locking moisture in the rocks. Jesse Lawrence of Scripps Institute of Oceanography in La Jolla, California, worked with Wysession to analyze the seismic signals through the mantle in the area beneath Asia‘s subduction zone. Just how far a subducting plate travels with all of its descending waterlogged makeup is a mystery. The scientific consensus has subducting plates reaching the lower mantle. ―Whether slabs penetrate to the core-mantle boundary or founder within the lower mantle, subduction clearly transports large volumes of material down into the lower mantle,‖ Lawrence and Wysession write in their report ―Seismic Evidence for Subduction-Transported Water in the Lower Mantle.‖ Finessing the plate tectonic paradigm continues. One of the most divisive of the debates remains whether the older, thicker subducting slaps do more of the work in pulling the thin young spreading ridges apart or whether the convecting mantle pushes the spreading ridges open. Plate tectonics experts on both sides of that debate are absolutely convinced of their having the correct interpretation, providing graduate students a potential minefield of opportunity.
密苏里州圣路易斯市华盛顿大学的迈克尔Wysession，发现他所谓的“湿点”。亚洲东部地区的下地幔像一块海绵一样，锁住了大量的水汽。杰西〃劳伦斯在加利福尼亚州拉霍亚的斯克里普斯海洋学研究所与Wysession工作分析地震信号通过下方的区域亚洲俯冲带
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地幔。加利福尼亚的La Jolla d的Scripps海洋研究院的杰西劳伦斯和Wysession 联合分析了地震波在穿过亚洲俯冲带的变化情况。板块俯冲有多远和如何降低含水量仍然是一个谜。下地幔俯冲板块这是科学届的共识。劳伦斯和wysession在他们的板块俯冲地震水输送中指出 “板块俯冲深入地幔地核的边界，为内地核输送了大量的物质”。灵巧的板块构造仍在继续。一个最具争议性的辩论，仍然是老的厚的板块俯冲扩张年轻的薄的板块使山脊分开或者是地幔对流推动山脊使山脊张开。板块构造专家，辩论双方都绝对相信他们有正确的解释，但这给研究生埋下了一个潜在的雷区的机会。
Paleoclimate from Caves and Lightning Bolts
In the 20th century, Earth scientists turned to tree rings, pollen, corals, seashells, and ice cores to understand Earth‘s past climate history. In the 21st century, a new generation of Earth scientists are also exploring the secrets of stalagmites in caves and finding unusual glassy shards in deserts that reveal shifts in climate as well. Geologist Jessica Oster began her work on stalagmite mounds in 2001 as an undergraduate conducting research at Oberlin College in Ohio. After studying Sweden‘s Quaternary landscape on a Fulbright scholarship, she turned her headlamp to the caves in California‘s Sierra Nevada Mountain Range. Around the world speleothems—icicle-shaped stalactites, stalagmite mounds, and flat flowstones that look like paint splatters on the ground—protected from erosion in caves, record in their drop-by-drop growth of mineral deposits how much moisture is in the soil and the air. In 2007 paleoclimatologists in Austria and Germany presented in their report ―Speleothems and paleoglaciers‖ evidence that ice does not preclude the formation of these water-borne structures. Geochemist Kathleen Johnson at the University of Oxford, United Kingdom, is investigating with colleagues the annual variations of trace gases in speleothems from Chinese caves. Having the advantage of annual or seasonal variation in mineral deposition, without erosion or bioturbation from worms, makes caves an ideal paleoclimate laboratory and new caves are being discovered every year. In 2006 amateur cavers found a million-year-old labyrinth in Sequoia National Park. The newly discovered cave section stretched more than 1,000 feet into the mountain.
在21世纪，地球科学家们利用树的年轮，花粉，珊瑚，贝壳，和冰芯了解地球过去的气候史。地质学家杰西卡奥斯特在2001年时开始了对石笋研究作为俄亥俄州奥伯林学院的一名本科生。在研究瑞典的第四纪景观在富布赖特奖学金，她带着头灯在加利福尼亚的内
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