Synthetic study on Proterozoic basic dyke swarms in the Qinling Orogenic Belt and its adjacent block as well as a discussion about some questions related to them

The basic dyke swarms is one of key indicators to construct the convergence and extension-rifling of ancient continental block. The synthetic analysis of the time-space correlation of Proterozoic basic dyke swarms developed i n Qinling orogenic belt and its adjacent North China block and Yangtze bloc k shows that there were two periods of basic dyke swarms formed in 2300Ma a nd 1700 similar to 1200Ma, respectively, reflecting the convergence and ext ension of ancient North China block in the Neo-Proterozoic and Paleo-Proter ozoic. While basic dyke swarms of 800 similar to 620Ma in the Yangtze block indicates the convergence and extension in the Neo-Proterozoic. Therefore, it can be concluded that the North China block and Yangtze block were sepa rated from each other in Pre-Sinian, and they were quite different blocks a nd possibly made up by different ancient continental blocks at that time. S o the orogenic process of Jining Period (1100 similar to 850Ma) and extensi on-rifting of Chengjiang Period (800Ma+/-) are very important periods which could be parallel with the periods of convergence and rifling of Neo-Prote rozoic Rodinia super-continent.