Geochemistry of evaporites of Chehl unit of Gachsaran Formation (Early Miocene) in the east of Bandar Khamir, Bandar Lengeh embayment with a special view on paleoclimate
Subject Areas : Petroleum Geology
Peyman Rezaei
1
,
Seyedeh Akram Jooybari
2
,
Faroogh Alian
3
1 -
2 - PhD in Sedimentology and sedimentary petrology, University of Hormozgan
3 - PhD student in sedimentology and sedimentary petrology, University of Hormozgan
Keywords: Geochemistry, Major and minor elements, Evaporites, Chehl unit, Gachsaran formation, Bandar khmir.,
Abstract :
Evaporitic formation of Gachsaran (Early Miocene) is known as the most important caprock of Middle East hydrocarbon reservoirs in Tertiary. This formation has good outcrops in the south of Bandar Lange embayment in the south-eastern folded Zagros, and in the east of Bandar Khamir, it includes three units: Chehl, Champeh and Mol. In this area, two sections of the 40th section of Gachasaran Formation, which includes evaporite deposits, were studied from a geochemical point of view, with an emphasis on paleoclimate and origin. For this purpose, 22 samples were taken from the vapors of both sections and subjected to XRF and ICP analysis. The results obtained from the main oxides show a negative correlation of Al2O3, K2O, Fe2O3 and a positive correlation of CaO with SO3, which indicates the prevailing conditions for are sulfate deposits and on the other hand, an increase in salinity in the basin. Investigations also show a negative correlation of secondary elements with SO3 oxide, which indicates the existence of 4 stages of drying and regression of the index in the period of settling of these evaporites. The outcrops of Hormoz series diapirs upstream and close to the studied area are proof of the impact of Hormoz series deposits on increasing the amount of secondary elements in the studied sequence.