University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 26 2 2015 06 01 High-Pressure Marbles from the Nahavand Area in the Sanandaj-Sirjan Metamorphic Belt, Iran 139 151 54646 EN J. Izadyar Department of Geology, Faculty of Sciences, University of Zanjan, Zanjan, Islamic Republic of Iran N. Skandari Department of Geology, Faculty of Sciences, University of Zanjan, Zanjan, Islamic Republic of Iran Journal Article 2015 01 14 <span>Marbles containing high-pressure mineral assemblage was found from the Sanandaj-Sirjan metamorphic belt in the Nahavand area in western Iran.  The high-pressure marbles occur as small bodies or lenses within pelitic schist layers and show compositional banding of carbonate- and silicate- rich bands.  Textural analysis revealed two metamorphic stages.  The early stage is testified by relicts of the minerals such as rounded jadeite-bearing diopside, epidote (clinozoisite), amphibole 1 (pargasite-edenite) and titanite 1. The second stage (main stage) documented to have phlogopite, chlorite, amphibole 2 (tremolite) and titanite 2. P-T-XCO2 estimates for the early stage of metamorphism give an average pressure, temperature and XCO2 of 13.5 kbar, 670 ºC and 0.35, whereas the second stage has been constrained at P=3.8 kbar, T=500 ºC and XCO2=0.45.  The high-pressure mineral assemblage documented in the Nahavand area, were formed during the subduction stage, while the second metamorphic blastesis were recorded during the exhumation event.</span> https://jsciences.ut.ac.ir/article_54646_6a93add471c4a58b97013924c2fd48b6.pdf