The Regional Crustal Mobility Reflected By the Geochemistry of Paleaozoic Sedimentary Rocks in South Qinling
南秦岭古生代沉积岩的地球化学特征及其反映的区域地壳活动性

The geochemistry of a geologic body is the record left by the chemical movement of earth materials. The involvement of deep lithospheric layers into geological processes in the surface is the reflection of regional crustal mobility. The regional crustal mobility of South Qinling during Paleaozoic era tended to become stronger gradually in Early Paleaozoic and weaker again in the Late Paleaozoic being strongest in Early Silurian epoch. Spatially, it got strongest along a nearly EW trending narrow and elongated zone composed of Ziyang-Zhuxi subarea and Kangxian-Baohe subarea closely adjacent to northern edge of Yangtze craton and Songpan--Ganzi massif seperately displaying distinct features in its eastern and western parts. Such a temporal and spatial frame of regional crustal mobility is considered to be related to the crustal extension of the northern margin of the united continent pieced together by Yangtze and Songpan-Ganzi blocks during the period from Neoproterozoic to Early Paleaozoic, and to the convergence and collision with North China craton by the end of Early Paleaozoic.