Study On NAMs In Hebi Area Of Henan Province And Its Implications For The Destruction Of North China Craton

Except the collision and dispersion of the plates,thermal-mechanical erosion of asthenosphere,as well as mantle replacement,the internal reorganization of minerals,fluid accumulation,etc.,also play a key role in the craton destruction.The structure water of NAMs has proved to be the main source of asthenospheric hydrothermal fluids,at the same time,it directly affects the melting,viscosity and hardness of the mantle lithosphere.Therefore,there is an inherent logical correlation between the cratonic damage and the "water" features of NAMs,establishing the connection between them is of great significance for the study of the stability of cratons.Hebi area is located in the transition zone between the crater and the stable craton in North China.The ultra-basic rock exposed in Hebi area are rich in mantle inclusions,which provide an important window for the study of the North China Craton since the Mesozoic.In this paper,through the means of electron probe and micro-Fourier transform infrared spectroscopy,we get the data of main elements and infrared absorption spectra of NAMs(mainly: olivine,clinopyroxene,orthopyroxene and garnet)in mantle inclusions,then this data were processed by several geological temperature gauges and water content analysis methods to obtain the temperature and pressure conditions,geochemical properties and water content of the internal NAMs of different depth mantle.Then combined with the ultrahigh-pressure water-phase silicate minerals and their transformation process rules,discussed the water-containing characteristics of NAMs and how they bring the "water" silicate minerals into the lower mantle and then crack to form magmatic and hydrothermal fluids through A,B,D,H,and other phase.Finally compared the NAMs characteristics of the long-term stable Craton(South Africa's Kaapvaal Craton)and the destructive Craton(North China Craton).It is concluded that the low water content of NAMs in the lithosphere mantle is the key to maintaining the stability of the craton,and the high water content of the NAMs and the rapid subduction of the plate result in the instability of the craton and affect its destruction.range.