Investigation of Organic Matters and their Roles in Deposition and Phosphate Mineralization in the Kuh-e-Sefid Deposit, Ramhormoz

• Main Authors: Houshang Pourkaseb, Alireza Zarasvandi, Zahra Fereydouni, Babak Mokhtari, Neda Mirzaei
• Format: Article in Journal/Newspaper
• Language: Persian
• Published: Ferdowsi University of Mashhad 2017
• Subjects: Matters; Apatite; Phosphate; Kuh-e-Sefid; Pabde formation; Geology; QE1-996.5; Planktonic foraminifera
• Online Access: https://doi.org/10.22067/econg.v9i1.49329; https://doaj.org/article/8b7b9324290e4155ab2b0e0e4d876902

Introduction It has been recently stated that phosphorite deposits are in fact marine biogenic materials, due to bacterial activity producing bio-apatite. In addition, Phosphorites contain 15–20 wt.% P2O5 (Tzifas et al., 2014). In this deposit, phosphate mineralization has occurred as phosphorite lenses with Eocene age within the Pabdeh Formation, with thickness up to 1.5 meters and width of 15 meters and its hosted rock is black shale. According to the presence of indices of fossils such as Globorotalia, Hantkenina, its age can be attributed to the middle Eocene. The Pabdeh formation is a very rich organic matter in addition to the presence of phosphate (Damiri, 2011). The formation due to planktonic foraminifera rich in organic matter is like the hydrocarbon source rock (Daneshian et al., 2012). In marine basins where upwelling and productivity are limited, phosphates may develop outside of microbial cells and also within bacterial cellular structures, formed by slow bacterial assimilation of phosphorus from assaying organic matter in areas of restricted sedimentation (O’Brine et al., 1981). It is therefore suggested that the upwelling currents did that in the recycling of phosphorus from dead organisms such as fishes and other marine vertebrates. The aim of this study is investigation of organic matter’s species and their roles in deposition and phosphate mineralization in the Kuh-e-Sefid phosphate deposit using XRD, FTIR and Rock-Eval pyrolysis. Materials and methods In field observations, 12 samples were selected and they were taken from units of phosphate and shale host rock in the Kuh-e-Sefid phosphate ore deposit. Ten cross sections were studied by conventional microscopic methods. Rock-Eval analysis was used in order to determine the organic carbon in the geology Department of the Shahid Chamran University of Ahvaz. The Phosphorite samples were determined by XRD at the Kansaran Binaloud Company in the Science and Technology campus in Tehran. FTIR analyses were carried out on the phosphorite samples in ...