本篇文章共分 5 段，針對 19 世紀歐、美兩套地球山脈形成理論分別說明其主要架構，以及對於長久以來地質學發現所提出的解釋方法。

本篇考題英文原文與對應之中文翻譯整理如下。練習作答解題時若有對語意不清楚之處，請仔細查閱對照，以提升閱讀理解能力。

Nineteenth-Century Theories of Mountain Formation 十九世紀的山脈形成理論

1. 山脈起源理論

   One of the central scientific questions of nineteenth-century geology was the origin of mountains. How were they formed? What process squeezed and folded rocks like bread dough? What made Earth’s surface move? Most theories invoked terrestrial contraction as a causal force. It was widely believed that Earth had formed as a hot, incandescent body and had been steadily cooling since the beginning of geological time. Because most materials contract as they cool, it seemed logical to assume that Earth had been contracting as it cooled, too. As it did, its surface would have deformed, producing mountains.

   十九世紀地質學的核心科學問題之一是山脈的起源。它們是如何形成的？是什麼過程使岩石像麵包團一樣被擠壓和折疊？是什麼使地球表面移動？大多數理論都將地球的收縮作為一種因果力量。人們普遍認為，地球形成之初是一個熾熱的耀眼物體，並且自地質時代開始以來一直在穩定地冷卻。由於大多數材料在冷卻時都會收縮，因此，假設地球在冷卻時也在收縮似乎是合乎邏輯的。在這種情況下，它的表面會發生變形，產生山脈。

2. 收縮的蘋果

   In Europe, Austrian geologist Eduard Suess (1831-1914) popularized the image of Earth as a drying apple: as the planet contracted, its surface wrinkled to accommodate the diminished surface area. Suess assumed that Earth’s initial crust was continuous but broke apart as the interior shrank. The collapsed portions formed the ocean basins, the remaining elevated portions formed the continents. With continued cooling, the original continents became unstable and collapsed to form the next generation of ocean floor, and what had formerly been ocean now became dry land. Over the course of geological history, there would be a continual interchange of land and sea, a periodic rearrangement of the landmasses.

   在歐洲，奧地利地質學家愛德華．修斯 (1831-1914) 將地球的形象廣為宣傳為一個乾燥的蘋果：隨著地球的收縮，它的表面起皺以適應縮小的表面積。修斯認為，地球最初的地殼是連續的，但隨著內部的收縮而破裂。崩潰的部分形成了海洋盆地，剩餘的升高部分則形成了大陸。隨著持續的冷卻，原來的大陸變得不穩定，塌陷形成了下一代的洋底，原來的海洋現在變成了乾燥的陸地。在地質歷史的進程中，陸地和海洋會不斷地交替，構成陸地的定期重新排列。

3. 岡瓦納大陸

   The interchangeability of continents and oceans explained a number of other perplexing geological observations, such as the presence of marine fossils on land (which had long before puzzled Leonardo da Vinci) and the extensive interleaving of marine and terrestrial sediments in the stratigraphic record. Suess’s theory also explained the striking similarities of fossils in parts of Africa and South America. Indeed, in some cases the fossils seemed to be identical, even though they were found thousands of miles apart. These similarities had been recognized since the mid-nineteenth century, but they had been made newly problematic by Darwin’s theory of evolution. If plants and animals had evolved independently in different places within diverse environments, then why did they look so similar? Suess explained this conundrum by attributing these similar species to an early geological age when the continents were contiguous in an ancient supercontinent called Gondwanaland.

   大陸和海洋的互換性解釋了其他一些令人困惑的地質觀察，例如陸地上出現的海洋化石（這在很久以前就令達文西感到困惑）以及地層記錄中海洋和陸地沉積物的廣泛交錯。修斯的理論還解釋了非洲和南美洲部分地區化石的驚人相似性。事實上，在某些情況下，這些化石似乎是相同的，儘管它們被發現時相隔數千英里。這些相似之處自 19 世紀中葉以來就得到了承認，但達爾文的進化論使它們成為新的問題。如果植物和動物是在不同的地方和不同的環境中獨立進化的，那麼為什麼它們看起來如此相似？修斯解釋了這個難題，他把這些相似的物種歸因於早期的地質時代，當時各大洲在一個古老的超級大陸上相鄰，稱為岡瓦納大陸。

4. 永久性理論

   Suess’s theory was widely discussed and to varying degrees accepted in Europe, but in North America geologist James Dwight Dana (1813-1895) had developed a different version of contraction theory. Dana suggested that the continents had formed early in Earth history, when low-temperature minerals such as quartz and feldspar had solidified. Then the globe continued to cool and contract, until the high-temperature minerals such as olivine and pyroxene finally solidified – on the Moon, to form the lunar craters; on Earth, to form the ocean basins. As contraction continued after Earth was solid, its surface began to deform. The boundaries between continents and oceans were most affected by the pressure, and so mountains began to form along continental margins. With continued contraction came continued deformation, but with the continents and oceans always in the same relative positions. Although Dana’s theory was a version of contraction, it came to be known as permanence theory, because it viewed continents and oceans as globally permanent features.

   修斯的理論在歐洲被廣泛討論並在不同程度上被接受，但在北美，地質學家詹姆斯．德懷特．達納 (1813-1895) 提出了一個不同版本的收縮理論。達納提出，大陸在地球歷史的早期就已經形成，當時低溫礦物如石英和長石已經凝固。然後地球繼續冷卻和收縮，直到高溫礦物如橄欖石和輝石最終凝固—這些在月球上，形成月球環形山；在地球上，形成海洋盆地。隨著地球凝固後收縮的繼續，其表面開始變形。大陸和海洋之間的邊界受壓力的影響最大，因此山脈開始沿著大陸邊緣形成。隨著持續的收縮，持續的變形，但大陸和海洋總是處於相同的相對位置。儘管丹納的理論是收縮論的一個版本，但它後來被稱為永久性理論，因為它將大陸和海洋視為全球永久的特徵。

5. 永久性理論的模糊之處

   In North America permanence theory was linked to the theory of subsidence (or sinking) of sedimentary basins along continental margins. This idea was developed primarily by paleontologist James Hall (1811-1898), who noted that beneath the forest cover, the Appalachian Mountains of North America were built up of folded layers of shallow-water sedimentary rocks, thousands of feet thick. How did these sequences of shallow-water deposits form? How were they folded and uplifted into mountains? Hall suggested that materials eroded off the continents accumulated in the adjacent marginal basins, causing the basins to subside. Subsidence allowed more sediment to accumulate, causing more subsidence, until finally the weight of the pile caused the sediments to be heated, converted to rock, and then uplifted into mountains. Dana modified Hall’s view by arguing that thick sedimentary piles were not the cause of subsidence but the result of it. Either way, the theory provided a concise explanation of how thick sequences of shallow-water rocks could accumulate, but was vague on the question of how they were transformed into mountain belts.

   在北美，永久理論與沿大陸邊緣的沉積盆地的沉降（或下沉）理論有關。這一觀點主要是由古生物學家詹姆斯．霍爾 (1811-1898) 提出的，他注意到在森林覆蓋之下，北美的阿巴拉契亞山脈是由折疊的淺水沉積岩層建立的，厚度達數千英尺。這些淺水沉積物的序列是如何形成的？它們是如何被折疊和隆起成山的？霍爾認為，從大陸上侵蝕下來的物質積累在鄰近的邊緣盆地，導致盆地下沉。下沉使更多的沉積物堆積，造成更多的下沉，直到最後堆積的重量導致沉積物被加熱，轉化為岩石，然後隆起成山。達納修改了霍爾的觀點，認為厚厚的沉積物堆不是下沉的原因，而是下沉的結果。不管怎麼說，該理論對厚厚的淺水岩層如何堆積提供了一個簡明的解釋，但對它們如何轉變為高山地帶的問題卻很模糊。