| The Khondalite series,Central Orogenic Belt and Jiao-Liao-Ji orogenic belt which are Palaeoproterozoic strips combination exist in the North China craton interior.The rock record,structural features and developed rich mineral resources preserved in orogenic belt are of significance for further study of precambrian structures and mineralization.This paper is based on orogenic metallogenic theory,integrated with multi-disciplinary sych as structural geology,petrology,mineralogy,geology,geophysics and so on,more systematic analysis of the depositional environment,shallow structural features,deep geological structure,ore controlling factors,metallogenic regularity,metallogenic model and prospecting indicators of the Jiao-Liao-Ji Paleoproterozoic orogenic belt.Besides,we can study Jiao-Liao-Ji Paleoproterozoic orogenic belt tectonic boundary,open polarity,tectonic evolution and mineralization deeply.Therefore,some major conclusions and knowledge are made as follows:1?According to the Jiao-Liao-Ji Paleoproterozoic orogenic belt developed the foliation(schistosity and gneissosity),tenacity,wrinkle and ductile deformation which have superposition and intersecting relationship.There are three phases of metamorphism and deformation in this era:the first phase is that southnorthward bedding extensional tectonic features represent the form of permeable flax and felsic strips.What's more,it is plastic shear mechanism and its occurrence has a trend of southnorth direction.It also associate the invasion of the pegmatite vein layer.The second phase is that southnorthward bedding extensional tectonic features represent the felsic strip and gneissic schistosity formed into a folded structure concurrently,accompanied by structural transposition and the form of the new gneissic schistosity,hook fold and rootless fold.The deformation of the silicification and amphibolization of griotte is more obvious.The direction of fold axial surface is nearly eastwestard.The last phase is that northeast-southwestward bedding extensional tectonic features represent the felsic strip and gneissic schistosity which formed early developed folds concurrently,accompanied by the form of northeast-southwestward wide-flat folds.Meanwhile,the deep geological structure of Caohekou synclinorium and Hupiyu anticlinorium revealed by geophysical methods are characteristic of strong folds.It indicates that the consistence and compatibility between deep and shallow tectonic features in Paleoproterozoic Era.2.According to the geological tectonic conditions,metamorphism,magmatism,sedimentation related to deposits' formation and the deposits' characteristics,we can divide the deposits in the Jiao-Liao-Ji Paleoproterozoic orogenic belt into two metallogenic series.The fist metallogenic series is that the boron,magnesite,talcum,phosphorus,graphite related to the paleoproterozoic sedimentary metamorphism.Its metallogenic model is that the Lvliang exhalation,hydrothermal condition and metallogenic epoches went through the deformation and metamorphism and superimposed mineralization The other is that the plumbum,magnesite,aurum,copper,molybdenum related to the mesozoic structure magmatism.Its metallogenic model is that the Lvliang exhalation,hydrothermal condition,metallogenic epoches and the mesozoic structure magmatism uperimposed metallogenic.3.The north tectonic boundary of Jiao-Liao-Ji orogenic belt is the line of Shi si county-Gongchangling-Lianshanguan-Caohekou town-Balidianzi town-Gucheng town-Two road baihe town.The east of boundary is North Korea.The south tectonic boundary is a line of Chen country-Lihuashan country-Hongqi country.Meanwhile,some geological body like the Palaeoproterozoic granite,mafic dyke and Mesozoic invision in Jiao-Liao-Ji orogenic belt recorded the complicated land movement and condition of structures of the Palaeoproterozoic Liao-Ji orogenic belt/mobile belt.It also indicates that Jiao-Liao-Ji orogenic belt's polarity may be from north to south.4.The geodynamic processes and metallogeny of the Jiao-Liao-Ji Paleoproterozoic orogenic belt recorded the complicated land movement and condition of structures of the can be divided into extensional period,extrusion orogenic period and non orogenic period.In extensional period,the sedimentation,volcanism and hydrothermal condition provide rich metallogenic material and good metallogenic environment.It is the formation period of the ore source layer.There are many folds and faults in extrusion orogenic period,and the distribution pattern of nonmetallic ore source layers is controlled.It provides ore migration for the metallogenic material and storage for metal ore fluid and the deep magmatic activities provide the source of power.So that the the formation and enrichment of orebodies are promoted.The non-orogenic tectonic movement further reformed the original ore deposits,and the magmatic activities again promoted further enrichment of the ore bodies. |
PDF Full Text Request