Volcanic deposits of the Qom Formation in Qamchoqay area (southwest Zanjan)
Authors
1
University of Zanjan
2
Department of Geology, Faculty of Science, University of Zanjan, Zanjan, Iran
Abstract
The Qom Formation sediments in the Qamchoqay region, southwest of Zanjan, are about 100 meters thick and consist mainly of thin to thick-bedded limestone, marly limestone, and marl. This Formation overlain Lower Red Formation with a disconformity, and is covered by the Upper Red Formation. Stratigraphically, this Formation in this area can be divided into two units; a limestone unit mainly in the basal and middle parts, and a marly unit in the upper section. The Qom Formation in the study area was formed in a carbonate platform shelf in the Early Miocene. The presence of volcanic and pyroclastic materials is observed in the upper marly parts of this Formation in the Qamchoqay section. This situation is similar to a number of other sections of the Qom Formation located in the Zanjan region and indicates extensive volcanic influences during the deposition of this Formation in the Early Miocene of this area. The fact that this area belongs to the Urmia-Dokhtar magmatic basin during sedimentation is the reason for the extensive volcanic effects in these deposits.
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