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Continental Drift | 100 Greatest Discoveries

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Continental Drift | 100 Greatest Discoveries

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Continental Drift | 100 Greatest Discoveries

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Alfred Wegener (1880-1930) became internationally known for his heavily disputed theory of continental drift, which he formulated as early as 1912. Yet his exploration of Greenland, as well as his related work in glaciology and aerology, also makes up a considerable part of his multifarious scientific career as a meteorologist and geophysicist.

Wegener lived in a period of tremendous political and scientific upheaval and transformation. Born in Berlin, he grew up in the German Empire at a time that saw the advent of new technologies such as the airship, electricity and the automobile. At that time Max Planck and Albert Einstein were calling the fundamentals of modern physics into question. In addition, geophysics, meteorology, and glaciology were changing into modern, globally oriented disciplines.

While his father was a theologian and classics teacher, Alfred and his older brother Kurt (1878-1964) were more inclined towards the natural sciences. Wegener studied mathematics and astronomy in Berlin and Heidelberg, but soon was drawn to geophysics and meteorology. Alfred, like his brother, enjoyed hiking, mountain climbing, and sailing. After the completion of his PhD in astronomy, he went together with his brother Kurt to the aeronautical observatory, the "Königlich Preußisches Aeronautische Observatorium Lindenberg" close to Berlin. Together they participated in ballooning and conducted meteorological observations in the new discipline of aerology. Together they set a world record for the longest time spent aloft in a balloon, remaining in the air for 52 hours from 5 to 7 April 1906. The experiences with kites and balloons as a meteorologist in the new field of aerology at Lindenberg gave him the unexpected opportunity to participate in the Danish Danmark Expedition to Greenland from 1906-1908.

Wegener's publications in the field of geophysics are remarkable because they are often based on intuitive insights and careful observations and encompass very different fields-the origins of continents and oceans, paleoclimatology, aerology, meteorology and atmospheric sciences, origins of craters on the moon, aurora and wind phenomena in the polar regions, or the origins of tornados and turbulence phenomena, and similar matters.

His close relationship with the climatologist Wladimir Köppen (1846-1940), whom he met at the kite station in Hamburg Großborstel in 1906 and would become his father-in-law, was very important for his further life and career. They discussed Wegener's ideas intensively. In 1911 Wegener formulated his ideas about the origins of oceans and continents for the first time. Also in this case it was an intuitive insight and immediate observation that made him think about the origins of continental movements. A letter from Wegener to Köppen, preserved at the Deutsches Museum, documents his ideas:

Marburg, 6 December 1911. Dear Father, I must answer your lengthy letter straightaway. I do believe that you consider my ancient continent to be far more fantastic than it really is and you do not yet see that it's merely a matter of interpreting the observation material. Even if I only arrived at the idea due to the correspondence between the coastlines, the documentation will naturally have to be based on material from geological observation.
-Letter of Alfred Wegener to his father-in-law, Wladimir Köppen, Marburg, 6 December 1911, DMA, HS 1968-596, 17.

Marburg, 6.12.1911. Lieber Vater, auf Deinen ausführlichen Brief muß ich Dir gleich antworten. Ich glaube doch, Du hältst meinen Urkontinent für phantastischer als er ist und siehst noch nicht, daß es sich lediglich um Deutung des Beobachtungsmaterials handelt. Wenn ich auch nur durch die übereinstimmenden Küstenlinien darauf gekommen bin, so muß die Beweisführung natürlich von dem Beobachtungsmaterial der Geologie ausgehen.
-Brief von Alfred Wegener an seinen Schwiegervater Wladimir Köppen, Marburg, 06.12.1911, DMA, HS 1968-596, 17.

On 6 January 1912, Wegener gave a courageous presentation at the annual meeting of the geological society ( Geologische Vereinigung) at the Senckenberg Museum in Frankfurt. This talk then was published as an article in the renowned journal Petermanns Geographische Mitteilungen [Alfred Wegener: Die Entstehung der Kontinente. In: Petermanns Mitteilungen 1912, pp. 185-95, 253-56, and 305-09]. In 1915 these ideas were then published as a book, Über den Ursprung der Kontinente und Ozeane (On the Origins of the Continents and Oceans), which was revised several times. However, during his lifetime Wegener did not receive recognition for his ideas. Only later, in the context of the systematic exploration of the seafloor in the 1950s, did observations of the phenomenon of seafloor spreading prove his insights.

In his Greenland diaries the theory of continental drift is only mentioned once in a rather ironic self-reflection about the difficult circumstances of polar exploration:

We certainly won't make it out of here today. And who knows how things will turn out tomorrow. One would think that this forced rest would encourage my mind to ponder, solve scientific questions, and to concentrate on things that I know I think about constantly when I am back home. But only once in a while do I find myself coming up with some unimpressive beginnings of ideas. All these problems, that of the volcanos, the cyclones, the blue strips in the ice, the daily fluctuation of the barometer, the rotation in the solar system, etc. are always with me; they are always sitting, so to speak, right in front of me, yet my imagination does not make it through, and instead chooses other paths. It persistently returns to two things, back and forth, and both are of a shamefully material nature: How will Else and I arrange things, and what kind of food will we cook? Note that the first question comes up primarily after our meals, the second before. I lack sufficient courage, otherwise I could write 2 disquisitions on these topics, in comparison with which the "Origin of Continents and Oceans" would look like an essay by a sixth-grader.
- Danish North Greenland Expedition, 19 May 1913, DMA NL 001/010, 55-57.

In 1913 he married Else Köppen (the daughter of his mentor Wladimir Köppen), with whom he had three children. During World War I Wegener worked as a meteorologist. In addition to these duties, he found time to write his famous book on continental drift. After World War I the ambitious and by then well-known Wegener was still having trouble finding a professorship. At that time he held a position at the Hamburger Seewarte observatory, succeeding his father-in-law Wladimir Köppen as leader of the meteorological branch. In 1924 he accepted an offer from the University of Graz (Austria), where he spent fruitful years as an academic teacher and researcher. In the early 1920s, academic life was still disrupted by the consequences of World War I. It took several years until the newly founded Notgemeinschaft der Deutschen Wissenschaft could support prestigious expeditions in remote areas to explore the oceans ( Meteorexpedition 1925-1927), the Pamir mountains expedition (1928), or Wegener's Greenland expeditions in 1929 and 1930-1931, which ended with the tragic death of Wegener and his companion, the Greenlander Rasmus Villumsen (1910-1930).

All in all, Wegener participated in four polar expeditions: the Danmark Expedition (1906-1908), the glaciological Danish North Greenland Expedition with Johann Peter Koch (1912), the pre-expedition (1929), documented neither in the Deutsches Museum archives nor in this virtual exhibition, and the German Greenland Expedition (1930-1931). He is well known as an expert on Greenland and for his close relations with the Inuit populations of Denmark and Greenland. Wegener was an experienced polar explorer and many of his scientific goals can be traced to the early expeditions where he was already starting to pursue glaciological and meteorological questions. Although his final expedition faced many difficulties and ended with his tragic death, it pursued an ambitious scientific program that served as a reference for subsequent international expeditions.

Today the German research institute for polar science and marine science is named the Alfred-Wegener-Institut für Polar- und Meeresforschung.

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Alfred Wegener (1880-1930) became internationally known for his heavily disputed theory of continental drift, which he formulated as early as 1912. Yet his exploration of Greenland, as well as his related work in glaciology and aerology, also makes up a considerable part of his multifarious scientific career as a meteorologist and geophysicist.

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In 1948, when Marie Tharp began working at the Lamont Geological Laboratory (now the Lamont-Doherty Earth Observatory at Columbia University), very little was known about the structure of the seafloor; it was thought to be mostly flat and featureless.

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Continental drift describes one of the earliest ways geologists thought continents moved over time. Today, the theory of continental drift has been replaced by the science of plate tectonics.

The theory of continental drift is most associated with the scientist Alfred Wegener. In the early 20th century, Wegener published a paper explaining his theory that the continental landmasses were "drifting" across the Earth, sometimes plowing through oceans and into each other. He called this movement continental drift.

Wegener was convinced that all of Earth's continents were once part of an enormous, single landmass called Pangaea.

Wegener, trained as an astronomer, used biology, botany, and geology describe Pangaea and continental drift. For example, fossils of the ancient reptile mesosaurus are only found in southern Africa and South America. Mesosaurus, a freshwater reptile only one meter (3.3 feet) long, could not have swum the Atlantic Ocean. The presence of mesosaurus suggests a single habitat with many lakes and rivers.

Wegener also studied plant fossils from the frigid Arctic archipelago of Svalbard, Norway. These plants were not the hardy specimens adapted to survive in the Arctic climate. These fossils were of tropical plants, which are adapted to a much warmer, more humid environment. The presence of these fossils suggests Svalbard once had a tropical climate.

Finally, Wegener studied the stratigraphy of different rocks and mountain ranges. The east coast of South America and the west coast of Africa seem to fit together like pieces of a jigsaw puzzle, and Wegener discovered their rock layers "fit" just as clearly. South America and Africa were not the only continents with similar geology. Wegener discovered that the Appalachian Mountains of the eastern United States, for instance, were geologically related to the Caledonian Mountains of Scotland.

Pangaea existed about 240 million years ago. By about 200 million years ago, this supercontinent began breaking up. Over millions of years, Pangaea separated into pieces that moved away from one another. These pieces slowly assumed their positions as the continent we recognize today.

Today, scientists think that several supercontinents like Pangaea have formed and broken up over the course of the Earth's lifespan. These include Pannotia, which formed about 600 million years ago, and Rodinia, which existed more than a billion years ago.

Tectonic Activity

Scientists did not accept Wegener's theory of continental drift. One of the elements lacking in the theory was the mechanism for how it works-why did the continents drift and what patterns did they follow? Wegener suggested that perhaps the rotation of the Earth caused the continents to shift towards and apart from each other. (It doesn't.)

Today, we know that the continents rest on massive slabs of rock called tectonic plates. The plates are always moving and interacting in a process called plate tectonics.

The continents are still moving today. Some of the most dynamic sites of tectonic activity are seafloor spreading zones and giant rift valleys.

In the process of seafloor spreading, molten rock rises from within the Earth and adds new seafloor (oceanic crust) to the edges of the old. Seafloor spreading is most dynamic along giant underwater mountain ranges known as mid-ocean ridges. As the seafloor grows wider, the continents on opposite sides of the ridge move away from each other. The North American and Eurasian tectonic plates, for example, are separated by the Mid-Atlantic Ridge. The two continents are moving away from each other at the rate of about 2.5 centimeters (1 inch) per year.

Rift valleys are sites where a continental landmass is ripping itself apart. Africa, for example, will eventually split along the Great Rift Valley system. What is now a single continent will emerge as two-one on the African plate and the other on the smaller Somali plate. The new Somali continent will be mostly oceanic, with the Horn of Africa and Madagascar its largest landmasses.

The processes of seafloor spreading, rift valley formation, and subduction (where heavier tectonic plates sink beneath lighter ones) were not well-established until the 1960s. These processes were the main geologic forces behind what Wegener recognized as continental drift.

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Continental drift describes one of the earliest ways geologists thought continents moved over time. Today, the theory of continental drift has been replaced by the science of plate tectonics.

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Alfred Wegener. The Origins of Continents and Oceans (4th edition)

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James Hutton used Steno's Law of Superposition. It compares rock layers to rocks above and below the rock. His evidence was that he found granite penetrating metaphoric schists, in a way which indicated that the granite had been molten at the time.

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The Plate Tectonics Revolution: Crash Course Geography #19

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지구가 살아있다는 증거! 대륙은 어떻게 이동 했을까?

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지구가 살아있다는 증거! 대륙은 어떻게 이동 했을까?

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지구가 살아있다는 증거! 대륙은 어떻게 이동 했을까?

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지구의 거대한 지각판 36억년 전 처음 움직이기 시작했다

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지구의 거대한 지각판 36억년 전 처음 움직이기 시작했다

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지구의 대륙과 해양 지각을 구성하는 10여개의 판이 36억년 전에 처음 움직이기 시작했다는 연구결과가 나왔다. 현재도 1년에 수cm씩 움직이며 지진이나 화산 활동을 만들어내는 지구의 판이 움직이기 시작한 시점이 규명된 것은 이번이 처음이다.

마이클 애커슨 미국 스미스소니언 박물관 연구원팀은 지구상에서 발견되는 가장 오래된 광물인 지르콘을 분석한 결과 36억년 전 지각판이 형성돼 움직이기 시작했다는 연구결과를 14일(현지시간) 국제학술지 '지오케미컬 퍼스펙티브 레터스'에 발표했다.

규산염 광물인 지르콘은 지층의 나이를 알려주는 '보석'으로 불린다. 내부 성분에 따라 다른 빛을 띠는 지르콘에는 우라늄 등 소량의 방사성 동위원소가 들어있다. 동위원소의 방사성물질의 양이 절반으로 줄어드는 반감기를 이용해 지르콘의 생성 연대를 측정할 수 있다. 풍화돼 없어지지 않는 한 잘 변질되지도 않아 생성 당시 정보를 그대로 담고 있다.

연구팀은 호주 웨스트오스트레일리아주 잭힐스에서 암석을 수집하고 분쇄해 머리카락만한 두께의 지르콘 알갱이 3500개를 얻었다. 44억년 전 만들어진 잭힐스 지역에서는 지난 2014년 지구에서 가장 오래된 암석으로 꼽히는 지르콘이 발견되는 등 30억년 전 보다 오래돼 지구 초기의 역사를 담은 지르콘이 다수 분포한다.

지르콘의 화학 성분을 분석한 결과 36억 년 전부터 암석 내 알루미늄 농도가 급격하게 증가하는 현상이 확인됐다. 알루미늄은 화학적 결합을 통해 지르콘과 결합하려면 고온과 고압의 극한 지질 조건이 필요하다. 연구팀은 이에 대해 과거보다 지구 표면 더욱 깊숙한 곳에서 암석이 만들어졌다는 뜻으로 해석했다. 이후 지구가 냉각하면서 표면이 암석으로 점차 굳고 지각이 두꺼워진 결과 현재 100km에 가까운 두께의 지각판이 만들어졌고 지각판들이 맨틀 위를 떠다니는 현재의 '판 구조론'이 시작됐다고 봤다.

연구팀은 캐나다 북부에서 발견된 40억년 된 아카스타 편마암에서도 이 시기 지각이 두꺼워지는 현상이 일어났다고 밝혔다. 애커슨 연구원은 "지르콘은 지구가 왜 독특한지에 대한 답을 줄수 있다"며 "약 36억 년 전 전 세계적으로 중요한 일이 일어났다"고 말했다.

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지구의 거대한 지각판 36억년 전 처음 움직이기 시작했다

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미국 스미스소니언 박물관 연구팀이 연구에 활용한 지르콘. 검은 원은 화학 성분을 분석하기 위해 레이저를 쏘며 생긴 구멍이다. 스미스소니언 박물관 제공 지구의 대륙과 해양 지각을 구성하는 10여개의 판이 36억년 전에 ...

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了解板块构造的历史和原理 

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了解板块构造的历史和原理 

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板块构造学是试图解释地球岩石圈运动的科学理论，这些运动形成了我们今天在全球范围内看到的景观特征。根据定义，地质术语中的"板块"一词是指一大块坚硬的岩石。"构造"是"建造"的希腊词根的一部分，这些术语共同定义了地球表面如何由移动的板块构成。

板块构造理论本身说，地球的岩石圈是由单独的板块组成的，这些板块被分解成十几块大大小小的固体岩石。这些碎片化的板块在地球流动性更强的下地幔顶部彼此相邻，形成不同类型的板块边界，这些边界在数百万年中塑造了地球的景观。

大陆漂移说

板块构造起源于 20 世纪初气象学家阿尔弗雷德·韦格纳 ( Alfred Wegener ) 首次提出的理论。1912 年，韦格纳注意到南美洲东海岸和非洲西海岸的海岸线似乎像拼图一样拼凑在一起。

对地球的进一步研究表明，地球上的所有大陆都以某种方式结合在一起，韦格纳提出了一个想法，即所有大陆曾一度连接在一个名为Pangea的超级大陆中。他认为，大约在 3 亿年前，大陆逐渐开始分开--这就是他的理论，后来被称为大陆漂移。

韦格纳最初理论的主要问题是他不确定大陆是如何彼此分开的。在寻找大陆漂移机制的整个研究过程中，韦格纳发现了化石证据，这些证据支持了他最初的泛大陆理论。此外，他还提出了关于大陆漂移如何在世界山脉建设中发挥作用的想法。韦格纳声称，地球大陆的前缘在移动时相互碰撞，导致陆地聚集并形成山脉。他以印度进入亚洲大陆形成喜马拉雅山为例。

最终，韦格纳提出了一个想法，将地球的自转及其向赤道的离心力作为大陆漂移的机制。他说盘古大陆从南极开始，地球的自转最终导致它分裂，将大陆推向赤道。这个想法被科学界拒绝了，他的大陆漂移理论也被驳回了。

责任编辑：

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了解板块构造的历史和原理_大陆_韦格纳_地球

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对地球的进一步研究表明，地球上的所有大陆都以某种方式结合在一起，韦格纳提出了一个想法，即所有大陆曾一度连接在一个名为Pangea的超级大陆中。在寻找大陆漂移机制的整个研究过程中，韦格纳发现了化石证据，这...

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Anfang des 20. Jahrhunderts behauptet Alfred Wegener, dass Kontinente sich durch die sogenannte Plattentektonik bewegen. Ältere Kollegen lachten. Zu Recht?

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Theorie Plattentektonik 1 – Alfred Wegener – Kontinentalplatten – Konvektionsströme – Folgen

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Theorie Plattentektonik 1 – Alfred Wegener – Kontinentalplatten – Konvektionsströme – Folgen

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Einfach erklärt - Geographie und Erdkunde

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Theorie Plattentektonik 1 – Alfred Wegener – Kontinentalplatten – Konvektionsströme – Folgen

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Placas tectónicas: cómo un descubrimiento de hace medio siglo se transformó en la clave para saber cómo funciona la Tierra

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Placas tectónicas: cómo un descubrimiento de hace medio siglo se transformó en la clave para saber cómo funciona la Tierra

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Cómo un descubrimiento de hace medio siglo se transformó en la clave para saber cómo funciona la Tierra - BBC News Mundo

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Se cumplen 50 años del descubrimiento de las placas tectónicas, uno de los grandes avances científicos del siglo XX porque no solo responde cómo se mueve la capa rígida exterior de la Tierra sino que da respuestas a muchas otras preguntas sobre la naturaleza.

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プレートテクトニクスの基礎1：海洋リソスフェアの生成と破壊

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プレートテクトニクスの基礎1：海洋リソスフェアの生成と破壊

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プレートテクトニクスの基礎1：海洋リソスフェアの生成と破壊