^*1Geology andMineral Exploration Groupof Baku State University, Azerbaijan Repulic Baku Z. Khalilov str. 23

²Karaj, Hesarak Town Science faculty, Geology Department Tarbiat Moallem University of Tehran Iran

Email:-mehdisafai_2000@yahoo.com

The best part of Kaolin and fireproof clay ore deposits of Azerbaijan Republic have been located in two regions of Lesser Caucasus: one around the Lok-Garabagh axis and the other in techtono-magmatic zone of Nakhjevan. From the most important deposits, the Chardakhli, Gutal, Chodardagh, etc. can be mentioned, located in Shekmir uplift. The XRD analyses results indicate that the most important clay minerals of these deposits include kaolinite, montmorillonite, dikkite, illite, pyrophillite and halloysite. Kaolinite is the most abundant and essential mineral in such ore deposits. Chemical combination of the deposits averagely includes: 20-40 % Al₂O₃, 49-78 % SiO₂ and less than 1.5 % Fe₂O₃. There is a negative correlation between the SiO₂ and Al₂O₃ values; that is, the ore deposits containing higher contents of SiO₂ contain lesser amounts of Al₂O₃. Kaolin and fireproof clay ore deposits of Azerbaijan Republic have been formed as a result of hydrothermal alteration process, low temperature hydrothermal-metasomatic alteration of intermediate to acidic combination igneous rocks, under the influence of acidic and sulphated hydrothermal fluids resulting from sub- volcanic phase activities after the acidic magma volcanism.