Zari Balaghi; Mahmoud Sadegheian; Habibollah Ghasemi
Volume 1, Issue 4 , March 2011, , Pages 45-64
Abstract
The extensive spectrum of intrusive and extrusive igneous rocks with bimodal nature have exposed in the south of Bahabad area, northeast of Bafq. The intrusive igneous rocks are gabbro ...
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The extensive spectrum of intrusive and extrusive igneous rocks with bimodal nature have exposed in the south of Bahabad area, northeast of Bafq. The intrusive igneous rocks are gabbro to granitic composition. The extrusive rocks compose of volcanosedimentary complex, known as Narigan series, alternation of basalt and rhyolite associated with pyroclastic rocks, sandstone, dolomite and evaporates (gypsum and halite). This complex displays features of shallow sedimentary and within plate environments. The presence of Archeocyatide fossil in the Limestone - dolomitic horizons and radiometric dating confirm Lower Cambrian age for this complex. The intrusive rocks mainly emplaced in the form of stock, dyke or sill intruded into the volcanosedimentary complex (Lower Cambrian) and Middle-Upper Cambrian and Ordovician deposits, therefore, these rocks are reffered to Lower Paleozoic. According to the geochemical data, gabbros and diorites are enriched in LREE and depleted in HREE and indicate alkaline within plate nature. The felsic rocks (leucogranites and rhyolites) indicate typical characteristics of crustal rocks. The leucogranites belong to I, H and A-Type granites. The magnetite, apatite, barite, lead and zinc mineralization in this area and adjacent regions (Bafq-Bahabad) are resulted from these magmatic evolutions.
