orthosyenite

In this area, there are both potassic (dominant) and sodic volcanic rocks (secondary); and there are also eruptive lavas (dominant), and some subvolc.

本区既有富钾质的 (主导 ) ,也有富钠质的火山岩 (次要 ) ;既有喷发熔岩流 (主导 ) ,也有一些浅源上侵的次火山岩体 ;火山活动发育在古近纪、新近纪与第四纪 ,而最强烈的发生在中新世期间。