The Cambrian Palaeogeograhy of Eastern Asia, I

Abstract

The Cambrian system of the Hwangho basin including North China, South Manchuria and North Korea is classified into 3 series and 9 stages and their lithofacies and faunas are briefly described. It is emphasized that the Kushan fauna indicates the final divergence and specialization of the Middle Cambrian or Fuchouan fauna. The Kushan stage is correlated to the passage beds between the Paradoxidian to the Olenidian series approximately from the Laevigata zone to the pisiformis zone. At present 36-37 fossil zones can be distinguished in the system at the maximum. Assuming the time-length of the Cambrian period to be 75 to 80 million years, the zone-time of the province is about 2 million years at the shortest.
In the Cambrian period the Koreo-Chinese heterogen to the north of the Tsinling-Huaiyang axis was divided into several zones on the east side and into a few blocks on the west side. These zones were equatorially elongated and the positive and negative ones disposed alternately from north to south. The western blocks were subrectangular and similar in size. The palaeogeographic changes were complicated by differential movements among these tectonic elements. Broadly speaking, however, the transgression and regression of the period were consisted of the Fuchouan grand cycle which was preceded by the Mantoan fluctuation and succeeded by the Chaumitian fluctuation. The Fuchouan cycle attained the inundation phase in the Changhian or most probably in the Taitzuan age.