Characteristics And Metallogenic Significance Of Enclaves Riched Iron In Diorite,Tanling Area Wuan,Hebei Province

Tan Ling ridge area is located in wuan,hebei province,is China's important iron base,tectonic located at the southern tip of taihang mountain,iron ore deposit formed during the middle-late Mesozoic era,120-135 ma;During the Mesozoic diorite temple ridge region found many dark particles of magnetite sodium feldspathic inclusions inclusions and the highest degree in magma transformation,close to the composition of magma,the temple hill rock mass may be direct crystal magma passage zhongfu sodium iron ore pulp,filling-injection type mineralization.Rich magnetite inclusions formed a round shape,half round,elliptic;Shaft diameter 2-11 cm long,the biggest is less than 30 cm;Inclusions and host rock mass boundary straight completely,common particle structure,embedded structure.Temple ridge rich magnetite main mineral inclusions are:hornblende(45%-50%),potassium feldspar(5%-15%),plagioclase(10%-20%),magnetite(15%-25%);Accessory minerals are:apatite(less than 5%),black mica,quartz(about 1%),etc.Host rock of main minerals are plagioclase(45%-50%),potassium feldspar(5%-15%),hornblende(10%-20%),chlorite(15%-25%);Accessory minerals are:magnetite(less than 5%),apatite,biotite,etc.Magnetite stone main minerals are magnetite(45%-50%),hornblende 15%-25%),plagioclase(10%-20%),potassium feldspar(5%-15%);Accessory minerals mainly include:black mica(less than 5%),apatite,etc.Rich magnetite in the inclusions plagioclase component:sodium feldspar,sodium feldspar,monoclinic feldspar,a few sanidine,or containing impurities such as Fe,Ti,Mg,Mn element;Al in crystal chemical formula are greater than 1.Host rock is feldspar:monoclinic sodium feldspar,sodium feldspar,a few for calcium feldspar and sanidine;Mineral feldspar as the more feldspar,monoclinic albite.Inclusion of hornblende for calcium hornblende;Magnetite,amphibole for Fe-Mg-Mn hornblende and calcium hornblende;Rock mass of hornblende for calcium and Na-Ca amphibole.By the main content,trace and rare earth data shows that the feldspar inclusions and mineral composition,can be divided into two categories:number(Ab)high and low brand(Ab)plagioclase;Ab early high of plagioclase is magmatic crystallization differentiation to form,and the Ab low albite and iron slurry formed at the same time.An oscillating band plagioclase in rock mass,center is a bit high,had An lower from center to edge,Ab,Or increased trend;An inclusion of hornblende center is a bit high,from the center to the edge has the tendency of the low Mg,Fe,Ca.Pressure gauge through flash Shi Wen Angle estimation:intrusive body,inclusions and ore body pressure range respectively focused on:2.34—3.52(Kbar),2.7—3.12(Kbar),4.02—6.65(Kbar),Rock mass,package and ore body temperature range respectively:966-1067(~OC),929-1062(~OC),730-956(~OC).The crystallization temperature of inclusions was slightly higher than that of rock mass,far higher than that of orebody,pulp temperature,reflects the late magmatic evolution.Magnetite assumes the circular,suborbicular to fill gap of hornblende and plagioclase and rock and mineral composition of plagioclase is consistent,that magnetite is the product of iron rich pulp from silicate melt away,and rich magnetite inclusions is"iron slurry from silicate melt from the middle of the product.Primitive magma which contain mineral melt fluid flow in the same period(magma and ore)is mainly originated from partial melting of upper mantle,part of the iron ore bed in the process of magma invasion on heating molten lower crust,crust-mantle mixed.Ore fluid melt flow migration along weak tectonic belt in place,rising in the process of Fe isotopes produced on the light under heavy fractionation,channel different parts have different fluid crystal mineral combination,is based on type formed into injection to final fracture and structural weak positions to fill-injection type mineralization enrichment.