CONDUCTIVITY ANOMALY IN THE LANZHOU-XIAN-ZHENGZHOU BELT

It is found, on the basis of 3SC and geomagnetic bays variations, that there is a zone of nearly vanishing Z with a east-west trend along Lanzhou-Xian-Zhengzhou belt. It is called the Lanzhou-Xian-Zhengzhou conductivity anomalous zone. There is some relationship among the following factors from studying the geological and geophysical characteristics along the zone. It is deduced that this zone may be a weak zone in the crust or a boundary between two sub-plates. It is also deduced that this zone may probably be related to the channel effect of the induced current in a larger region.