寒武纪 Cambrian

构造运动

Plate reconstructions suggest a global supercontinent, Pannotia, was in the process of breaking up early in the period, with Laurentia (North America), Baltica, and Siberia having separated from the main supercontinent of Gondwana to form isolated land masses.

板块重建意味着一个全球性的超级大陆潘诺西亚大陆，正处于分裂的早期阶段，而且劳伦大陆（北美地区）、波罗地大陆和西伯利亚也已经从主超级大陆冈瓦纳古大陆中分离出来，形成独立的板块。

Most continental land was clustered in the Southern Hemisphere at this time, but was gradually drifting north. Large, high-velocity rotational movement of Gondwana appears to have occurred in the Early Cambrian.

大多数大陆在那时都聚集在南半球，但是逐渐在向北漂移。巨大的、高速的冈瓦纳古大陆旋转运动似乎也在早寒武世就出现了。

With a lack of sea ice – the great glaciers of the Marinoan Snowball Earth were long melted– the sea level was high, which led to large areas of the continents being flooded in warm, shallow seas ideal for thriving life.

因为缺乏海上冰层——Marinoan Snowball Earth的巨大冰川长时间地融化——海平面变得很高，导致了大面积地陆地被温暖的浅海覆盖，而这又提供了生物繁荣兴盛的条件。

The sea levels fluctuated somewhat, suggesting there were ‘ice ages’, associated with pulses of expansion and contraction of a south polar ice cap.

海平面有所波动，暗示着那时曾经存在着与南极冰盖脉冲式的扩张与收缩有关的“冰河时代”。

气候特征

 

The Earth was generally cold during the early Cambrian, probably due to the ancient continent of Gondwana covering the South Pole and cutting off polar ocean currents.

早寒武纪时期，地球整体上较为寒冷，很有可能是因为古冈瓦纳大陆覆盖了南极点，并隔断了极点附近的洋流。

There were likely polar ice caps and a series of glaciations, as the planet was still recovering from an earlier Snowball Earth.

由于地球仍正在从早期的“雪球”状态中恢复，所以极点附近很有可能有冰盖和一系列冰川。

It became warmer towards the end of the period; the glaciers receded and eventually disappeared, and sea levels rose dramatically. This trend would continue into the Ordovician period.

寒武纪晚期变得温暖了些：冰川消融，最终消失；海平面大幅度上升。这种趋势持续到奥陶纪。

生物特征

标志着有钙质和硅质骨骼的生物的初次出现。几乎所有重要的无脊椎动物门类都已出现，但处于演化初期阶段。动物群以具有坚硬外壳的、门类众多的海生无脊椎动物大量出现为其特点，是生物史上的一次大发展。其中三叶虫最为常见，是划分寒武系的重要依据。其次有其次是腕足动物、古杯动物、棘皮动物和腹足动物，如有无铰、几丁质外壳的

腕足类小舌形贝、小园货贝以及古杯类和软舌螺等。

植物群以藻类为主，还有一些微古植物。寒武纪没有真正的陆生生物。