Geological structures related to the dolomitization process of the Jurassic strata in the south of Zanjan
Document Type : Original Article
Authors
1
Geology department,, Faculty of science, University of Zanjan. Zanjan. Iran
2
Geology department, Faculty of science. University of Zanjan
3
Geology department, Faculty of science, University of Zanjan
4
Zanjan Cement Factory
Abstract
Field geology, structural geology and sedimentological studies have been carried out on Jurassic strata (Shemshak, Dalichai and Lar Formations) in three stratigraphic sections (Yengejeh, Mohammad-Abad and Boolamaji) in the south of Zanjan in order to achieve the role of tectonic activities on dolomitization diagenetic process. Structural geology studies show several oblique-slip faults (Right lateral-Normal) with NE-SW strike in this area. Faults geographic pattern are related to the dolomitic zones in the Dalichai and Lar Formations strata. The most of the dolomitization process have happened along fault area. Also, there are more limestone zones far from the structural zones. There is no relation between dolomitization process and layers in this area and we can see the dolomite zones as patch dolomite between limestone strata. Petrographic studies show large scale dolomite crystals with non-flat boundary and undulatory extinction that created in the burial system related to the tectonic activities. The source of magnesium in the dolomitization process in this area can be from intrusive mass along the fault zones that effects on carbonate strata through the faults and joints.
Keywords
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