The ultimate expanding earth hypothesis
The ultimate expanding earth hypothesis
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地球终极膨胀假说
DOI：
10.1111/j.1365-2699.2003.01049.x
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发表时间：
2004
影响因子：
3.9
通讯作者：
J. C. Briggs
中科院分区：
文献类型：
--
作者：
J. C. Briggs
在他关于跨太平洋关系的论文的导言中，麦卡锡（2003）同意扩张地球理论的极端观点，认为在侏罗纪之前，地球是一个完全陆地的小地球仪。他的推理很简单：世界上所有海洋的底部都是在不到200 Ma的时间内形成的，因此在此之前海洋并不存在。当然，这是一个合理的论点，只有当一个人准备忽略一些公认的事实：（1）前寒武纪到古生代的海洋生物化石记录提供了广泛的海洋证据;（2）扩张地球理论未能通过严格的古地磁测试（McElhinny等人，（1978年）;（3）没有因膨胀而导致的行星裂缝（Hallam，1994年）;（4）自三叠纪以来，海平面没有因膨胀而急剧下降;（5）有大量证据表明，大规模俯冲作用吞噬了较老的海底;（6）缺乏证据证明膨胀所必需的内能的产生（Bursa & Hovorkova，1994）;（7）没有证据表明膨胀会导致地球自转速度的迅速降低（Bursa，1993）。欧文（1976）发表了一个不那么极端的地球膨胀观点，随后发表了他的《大陆位移地图集》（欧文，1983）。欧文认为，他有地质学证据表明，只有当地球的直径是现代平均直径的80%时，大陆才能结合在一起形成盘古大陆。否则，大陆从现在的位置重新组合回到盘古大陆的起点，就会留下一系列巨大的V形缺口。欧文的地图，说明了在过去的200 Ma的20%的扩张，是感兴趣的一些地质学家。然而，Weijermars（1986）表明，如果使用三维地球仪，而不是地图投影，差距将消失。考克斯（1990）发表的简明评论本应让膨胀地球理论偃旗息鼓，但遗憾的是，它又一次出现了。McCarthy（2003）的扩张主义论文认为，太平洋是由新大陆的西海岸与亚洲的东海岸分离而形成的，这一事件发生在不到200 Ma的时间内。为了支持这一观点，他利用了两种证据，地质学和生物学。前者包括任意移动的大陆块和海沟，以便在三叠纪时，两岸的海岸线可以结合在一起。可以说，缺乏这种排列的地球物理证据。他的论点的主要部分包括广泛的文献参考跨太平洋的动物和植物，据说无法实现长距离传播。引用文章的作者在很大程度上是分享扩张主义哲学的人。即便如此，对这些信息的一般性反驳可能会引起考古学家的兴趣。大部分生物学证据（约5页）都致力于南大洋的关系，特别强调了新西兰和智利南部的假定并列。板块构造重建（Lawver等人，1992年）的晚白垩世研究表明，南极半岛的顶端位于火地岛附近，塔斯马尼亚和南塔斯曼海岭形成了澳大利亚和南极洲之间的连接纽带。这些位置保持相对稳定，直到始新世晚期，大约40 Ma，之后澳大利亚迅速向北移动。白垩纪末期海平面下降（Hallam，1994年），使大陆架大量暴露，缩短了海岸线之间的距离，为陆地生物群的迁移提供了更多的机会。大约60-40 Ma的迁徙机会窗口允许形成通常被称为两性通道的东西。南美和澳大利亚之间的联系最紧密，其次是新西兰。南部非洲、马达加斯加和新喀里多尼亚显示出更远的关系（Briggs，1995年）。澳大利亚和南美洲的关系表现在大部分的植物群和动物群上。该列表包括脊椎动物，如有袋类哺乳动物，剑齿鳄，青蛙家族Leptodactylidae，海龟家族Chelidae，平胸鸟和土墩鸟。无脊椎动物包括淡水贻贝、小龙虾和水生昆虫，如蜉蝣、石蝇、石蝇等。也包括许多陆生无脊椎动物，如陆生蜗牛，寡毛类蠕虫，以及大多数主要的昆虫和蜘蛛。像澳大利亚一样，新西兰可能在三叠纪或侏罗纪接受了最早的脊椎动物（恐龙，一种leiopelmatid青蛙及其tatara物种）。但是，在第三纪早期，它也通过南极洲和澳大利亚接受了来自南美洲的生物群的注入。与澳大利亚不同的是，新西兰当时除了鸟类和可能的蜥蜴外没有脊椎动物。平胸鸟、恐鸟和几维鸟可能在第三纪早期到达。它们的迁徙很容易，因为它们的祖先可能是与南美洲和中美洲tinamous有关的飞鸟（Briggs，2003）。对新西兰植物群起源的回顾（Pole，1994）表明，新西兰与澳大利亚有着密切的关系，新西兰现在的植被完全或几乎完全是第三纪长距离扩散的结果。应该指出的是，并非所有的两栖动物迁徙都是从西向东移动的。从东南亚到一般的澳大利亚-新西兰地区，有一个显着的原始针叶树和被子植物家庭的浓度。它们中的一些在南美洲被发现，它们很可能是从东方来的。生物地理学杂志（J. Biogeogr.）（2004）31，855-857
In the introduction to his paper on transPacific relationships, McCarthy (2003) agrees with an extreme view of the expanding earth theory that calls for a small, pre-Jurassic globe that was completely terrestrial. His reasoning is straight forward: the floor of all the world’s oceans was formed less than 200 Ma, therefore oceans did not exist prior to that time. Of course, this is a reasonable thesis only if one is prepared to ignore a number of well-established facts: (1) the Precambrian to Paleozoic fossil record of marine life providing evidence of extensive oceans; (2) the failure of the expanding earth theory to pass a rigorous paleomagnetic test (McElhinny et al., 1978); (3) the absence of cracks across the planet caused by expansion (Hallam, 1994); (4) The absence of a drastic fall in sea level since the Triassic that would have been caused by expansion; (5) the abundant evidence of large-scale subduction that absorbed the older sea floor; (6) the lack of evidence for the generation of the internal energy necessary for expansion (Bursa & Hovorkova, 1994); and (7) no evidence of the rapid reduction in the earth’s rotation that would be caused by expansion (Bursa, 1993). A less extreme view of earth expansion was published by Owen (1976) and this was followed-up by his Atlas of Continental Displacement (Owen, 1983). Owen felt that he had geological evidence that the continents could fit together to form Pangaea only if the earth’s diameter was 80% of its modern mean value. Otherwise, a reassembly of the continents from their present positions back to their pangaean beginning would leave a series of large V-shaped gaps. Owen’s maps, illustrating a 20% expansion over the past 200 Ma, were of interest to a number of biogeographers. However, Weijermars (1986) showed that if a three-dimension globe is used, instead of map projections, the gaps will disappear. The concise review published by Cox (1990) should have laid the expanding earth theory to rest, but alas it has arisen once more. The expansionist paper by McCarthy (2003) maintains that the Pacific Ocean was formed by the separation of the west coast of the New World from the east coast of Asia and that this event took place in less than 200 Ma. In support of this idea, he utilizes two kinds of evidence, geological and biological. The former consists of arbitrarily shifting continental blocks and oceanic trenches about so that, in the Triassic, the shorelines of the two sides would fit together. It may suffice to say that geophysical evidence of such an arrangement is lacking. The major part of his argument consists of extensive literature references to transPacific animals and plants that are supposedly unable to achieve long-distance dispersal. The authors of the referenced articles are, in large part, people who share the expansionist philosophy. Even so, a general rebuttal to such information may be of interest to biogeographers. The great bulk of the biological evidence (about five pages) is devoted to relationships across the Southern Ocean and, in particular, emphasizes the supposed juxtaposition of New Zealand and the southern part of Chile. Plate tectonic reconstructions (Lawver et al., 1992) for the late Cretaceous show that the tip of the Antarctic Peninsula was located close to Tierra del Fuego and that Tasmania, and the South Tasman Ridge, formed a connecting link between Australia and Antarctica. These positions remained relatively static until the late Eocene, about 40 Ma, after which Australia moved rapidly northward. The drop in sea-level at the end of the Cretaceous (Hallam, 1994) allowed considerable exposure of the continental shelves that lessened the distance between shore lines, and provided increased opportunity for migration of the terrestrial biota. The window of migratory opportunity, that was available from about 60–40 Ma, permitted the formation of what is often called an amphinotic track . The strongest ties are between South America and Australia followed by New Zealand. More distant relations are shown by southern Africa, Madagascar, and New Caledonia (Briggs, 1995). Australian–South American relationships are demonstrated by a large fraction of the flora and fauna. The list includes vertebrates such as the marsupial mammals, xiphodont crocodiles, the frog family Leptodactylidae, the turtle family Chelidae, ratite birds, and mound birds. The invertebrates include freshwater mussels, crayfish, and aquatic insects such as the mayflies, stoneflies, caddiceflies, and others. Also included are a host of terrestrial invertebrates such as land snails, oligochaete worms, and most major groups of insects and spiders. Like Australia, New Zealand probably received its earliest vertebrates (dinosaurs, a leiopelmatid frog and its tautara species) in the Triassic or Jurassic. But, during the early Tertiary, it too received an infusion of biota from South America via Antarctica and Australia. Unlike Australia, New Zealand received no vertebrate animals at that time except birds and possibly some lizards. The ratite birds, moas and kiwis, probably arrived in the early Tertiary. Their migration was facilitated because their ancestors were probably flying birds related to the South and Central American tinamous (Briggs, 2003). A review of the origins of the New Zealand flora (Pole, 1994) indicates a close relationship to Australia, and that the present vegetation of the former is entirely, or almost entirely, the result of long distance dispersal during the Tertiary. It should be noted that not all of the amphinotic migratory traffic moved from west to east. From southeast Asia to the general Australian–New Zealand region, there is a remarkable concentration of primitive conifer and angiosperm families. A few of them are found in South America and it is likely that they arrived from the east. Journal of Biogeography (J. Biogeogr.) (2004) 31, 855–857