大旋回 meaning in English

macrocycle

On the basis of study on petrology , volcanic geology , geochemistry , isotopic chronology , antitheses of the regional strata and 4 suits of volcanic rock stratum of the yanshan - liaoning area , the rhythm of yanshanian volcanic activity is divided into 1 gigantic - cycle , 4 cycles , 11 micro - cycles , 24 sub - cycles and many rhythms . in addition , the temporal and spatial evolution and regional contrast of every - level rhythms are discussed . 3 . based on the study on classifications of rhythm of volcanic activity and regional contrast , the petrology , mineralogy , geochemistry , and isotopic characteristics of every - level rhythms are discussed
2 、通过对燕辽地区燕山期发育的四套火山岩的岩石学、火山地质学、地球化学、同位素年代学的综合研究，通过运用综合方法进行区域地层对比和分析火山喷发盆地火山岩地层特征的基础上，将本区燕山期火山活动节律，划分为1个二级节律(大旋回) 、 4个三级节律(旋回) 、 11个亚三级节律(小旋回) 、 24个四级节律(亚旋回)和多个五级节律(韵律)等，论述了各级火山活动节律特征及其时空演化和区域对比。