Geology and genesis of the tarom zone Iron oxide - Apatit deposits, ( ZANJAN )
|Location||23th symposium on geosciences|
|Holding Date||05 May 2008|
The Tarom area belongs to the west Alborz structural zone , and is located in Zanjan province. Eocene volcanic rocks ( lava and pyroclastic ) and granitoid intrusions (granite,granodiorite,monzogranite and quartz monzonite ) Outcrop in this area, that small and big granitoid bodies intruded into the volcanic rocks. Alteration processes acted large scale in Tarom area, so that argilitic, alunite, silicification alterations is observed in the intrusive bodies, Of epidotic and chloritic in volcanic rocks. One of the most important phenomena is the existence of marginal and vein faces in Tarom granitoid rocks. Geotectonic diagrams exhibit granitoids are synorogenic and postorogenic ,of andesites have island arcs environments. Granitoids are I type and their chemical composition correspond to the calco- alkaline magmatic series. The existence data clearly identifies granitoidic magma was rich in Iron, and during magmatic differentiation with increasing of Oxygen fugacity, Iron oxide - apatite melt separated from silicic liquid, and formed Iron Oxid - apatite mineralization in granitoid rocks at variable ratios accompanied quartz, calcite and copper minerals. The form of mineralization vary in shape from massive to veins, vein lets and dissemination. Apatits are coarse grain and have bipyramidal and spindel forms, that filled by quartz and calcite. Apatite veins with white and pink colors was final phase of mineralization, and Iron Oxide - apatit mineralization Occurred as marginal differentiation form in batholitic body. Width of Iron Oxide - apatite veins varies from 1 to 2m, and length of outcropped lenses and veins are variable and is 25 to 100m. The content of P2O5 in analized samples varies from %4 to %22, and have anomalous values relative to some of trace elements ( values of Nb and Ta is >2000ppm ). There are 5 Iron oxide - apatite bodies at tarom zone. There from Iron oxide - apatite bodies have same strike with intrusive bodies of north Azerbaijan, there for Tarom intrusive bodies can be notice as an exploration criteria for Iron - oxide, apatite deposite in the range of west Alborz - Azerbaijan.