泥盆纪 Devonian Period

构造运动

The Devonian period was a time of great tectonic activity, as Euramerica and Gondwana drew closer together.

泥盆纪时期是一个板块运动活跃的时期，比如欧美大陆和冈瓦纳古大陆更为接近。The continent Euramerica (or Laurussia) was created in the early Devonian by the collision of  Laurentia and Baltica, which rotated into the natural dry zone along the Tropic of Capricorn, which is formed as much in Paleozoic times as nowadays by the convergence of two great air-masses, the Hadley cell and the Ferrel cell.

欧美大陆（或者劳伦西亚大陆）是在早泥盆世由于劳伦大陆和波罗地大陆碰撞而产生的，缓缓      转入北回归线附近的自然烦躁地区，这块区域是由于在多个古生代就有的两个大气团的收敛，哈得莱环流和费雷尔环流。

In these near-deserts, the Old Red Sandstone sedimentary beds formed, made red by the oxidized iron (hematite) characteristic of drought conditions.

在这些临近的沙漠中，古老的红色砂岩层形成，变红是由于干旱地区被氧化的铁（赤铁矿）特征。

Near the equator, the plate of Euramerica and Gondwana were starting to meet, beginning the early stages of assembling Pangaea. This activity further raised the northern Appalachian Mountains and formed the Caledonian Mountains in Great Britain and Scandinavia.

在赤道附近，欧美板块和冈瓦纳古大陆开始接触，开始了泛大陆的早起聚集。这项活动更深层次地导致北部阿巴拉契亚山脉的隆升和在英国和斯堪的那维亚加里东山脉的形成。

The west coast of Devonian North America, by contrast, was a passive margin with deep silty embayments, river deltas and estuaries, in today’s Idaho and Nevada.

相比之下，在泥盆纪时期的北美西海岸，是一个无源的深层粉砂质的边缘，而在今天的爱华达州和内华达州，是河口三角洲和河口湾。

An approaching volcanic island arc reached the steep slope of the continental shelf in Late Devonian times and began to uplift deep water deposits, a collision that was the prelude to the mountain-building episode of Mississippian times called the Antler orogeny.

逐渐接近的的火山岛弧在晚泥盆纪时期达到大陆架的大陆坡，渗水沉积开始隆起，碰撞是密西西比鹿角造山事件的前奏曲。

Sea levels were high worldwide, and much of the land lay under shallow seas, where tropical reef organisms lived. The deep, enormous Panthalassa(the “universal ocean”) covered the rest of the planet.

全球范围内海平面上升，许多陆地都被适合热带珊瑚生物居住的浅海覆盖。在深部，泛大洋覆盖了地球的其他地方。

气候特征

The Devonian was a relatively warm period, and probably lacked any glaciers. The temperature gradient from the equator to the poles was not as large as it is today. The weather was also very arid, mostly along the equator where it was the driest.

泥盆纪是一个相当温暖的时期，可能没有任何冰川。赤道与极点之间的温差并不像现在这么显著。赤道两边最为干旱。

Reconstruction of tropical sea surface temperature from conodont apatite implies an average value of 30 °C (86 °F) in the Early Devonian.CO2 levels dropped steeply throughout the Devonian period as the burial of the newly evolved forests drew carbon out of the atmosphere into sediments; this may be reflected by a Mid-Devonian cooling of around 5 °C (9 °F).

从牙形虫磷灰石分析得出早泥盆纪时，热带海洋表面温度约30摄氏度。二氧化碳浓度在整个石炭纪时期大幅度降低，主要是因为新进化出的森林大量死亡（可能是中泥盆纪时气温降低了5摄氏造成的）后埋到地底，将空气中的二氧化碳变成了沉积岩。

The Late Devonian warmed to levels equivalent to the Early Devonian; while there is no corresponding increase in CO2 concentrations, continental weathering increases (as predicted by warmer temperatures); further, a range of evidence, such as plant distribution, points to Late Devonian warming.

晚泥盆纪升温到与早泥盆纪一样温暖，但却没有相应的二氧化碳浓度的提升与大陆尺度上增强的风化作用（高温本应使风化作用增强）。此外，很多证据证明了晚泥盆纪的温暖，例如植物的分布等。

生物特征

【鱼类时代】脊椎动物进入飞跃发展时期，各种鱼类空前繁盛，有颌类、甲胄鱼数量和种类增多，现代鱼类——硬骨鱼开始发展。因此，泥盆纪常被称为“鱼类时代”。在泥盆纪晚期，由鱼类进化而来的两栖类登上陆地，标志着脊椎动物开始了脱离水体并最终征服陆地的演化历程。

陆生植物裸蕨在陆地上完全站稳了脚根，并且，它们的三支后代石松类、楔叶类和真蕨类开始大发展，到泥盆晚期，出现了许多这类植物构成的成片森林。

泥盆纪中晚期的陆地上还出现了最早的裸子植物，但直到二叠纪晚期它们才成为陆地植物的主角。

泥盆纪时，海生无脊椎动物的组成发生了重大变化。古生代早期极为繁盛的三叶虫只剩下少数代表；奥陶纪和志留纪非常繁荣的笔石仅剩下少量的单笔石和树笔石类；菊石正逐渐取代鹦鹉螺类成为软体动物中的主要类群。腕足动物和珊瑚动物有进一步发展，但种类与奥陶纪和志留纪有所不同，这一时期的腕足动物主要以石燕类为主，而珊瑚则以床板珊瑚和四射珊瑚为主。