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Geology, geochemistry and evolution of the Esfordi Phosphate - Iron Deposit, Bafq Area, Central Iran
Geology, geochemistry and evolution of the Esfordi Phosphate - Iron Deposit, Bafq Area, Central Iran
dc.contributor.author | Jami, Morteza | en_US |
dc.date.accessioned | 2022-03-21T16:21:27Z | |
dc.date.available | 2022-03-21T16:21:27Z | |
dc.date.issued | 2005 | en_US |
dc.description.abstract | Esfordi is a Kiruna-type Fe–P oxide deposit in the Bafq district of Iran. It formed within a predominantly rhyolitic volcanic sequence that formed in a continental margin tectonic regime and is of Cambrian age. The gently dipping, stratabound ore body is lenticular and displays a well-developed mineralogical zonal pattern. The Fe-oxide rich core contains a central zone of massive magnetite and a more hematitic brecciated rim. The overlying P-rich ore body contains massive and brecciated, apatite-rich variants with accessory hematite and actinolite. A zone of apatite-bearing veins and disseminations envelopes the Fe-oxide and P-rich zones and extends into overlying volcaniclastics that contain detrital magnetite ± apatite clasts. The main ore zones are surrounded by Ca-rich alteration, dominated by actinolite, extending ~100 m into the more permeable overlying volcaniclastics. Beyond this envelope is widespread development of secondary K-feldspar. Mesoscopic and microscopic observations reveal a paragenetic sequence containing four generations of apatite. The early stage is a LREE-rich apatite 1 that occurs within the massive and brecciated magnetite core. The second generation is large and brecciated apatite 2, associated with hematite and actinolite. Both apatite 1 and 2 exhibit widespread dissolution and reprecipitation to form a LREE-poor granular apatite that is generally associated with quartz-carbonate±REE minerals. The final stage involved an overprint of LREE-poor apatite 3-carbonate-quartz-actinolite-chlorite-epidote±bastnaesite±synchesite extending into the host rocks. Fluid inclusions in apatite 1 have homogenisation temperatures of 375-425oC and indicate salinities of 14–18 wt. % NaCl. The magnetite displays low δ¹⁸O of -0.1–1.7 ‰, suggesting precipitation from fluids with δ¹⁸O of 7.8–9.6 ‰ at ~400oC, consistent with a magmatic source. Fluid inclusions in apatite 2 homogenise between 195–295oC with indicated salinities of 13–19 wt. % NaCl. The associated hematite displays δ¹⁸O of -0.2–2.3 ‰ which would be in equilibrium with fluids having a δ¹⁸O of 10.7–13.0 ‰ at ~250oC. Such enriched isotopic fluids suggest interaction of magmatic fluids with cooler saline fluids that were probably derived from the underlying carbonate-rich sequences. Fluid inclusions in apatite 3 and quartz homogenise at 145–155oC and, together with a quartz δ¹⁸O of 16.0–17.1 ‰, suggests precipitation from a fluid with δ¹⁸O of -0.7–2.1 ‰ that is likely to have resulted from the introduction of a cooler, less saline and isotopically depleted fluid (such as sea water). The results of this study clearly indicate a significant role for fluids in the evolution of the Esfordi deposit but do not preclude a role for immiscible Fe-oxide��������P-rich melts in the initial stages of the mineralising process. | en_US |
dc.identifier.uri | http://hdl.handle.net/1959.4/32745 | |
dc.language | English | |
dc.language.iso | EN | en_US |
dc.publisher | UNSW, Sydney | en_US |
dc.rights | CC BY-NC-ND 3.0 | en_US |
dc.rights.uri | https://creativecommons.org/licenses/by-nc-nd/3.0/au/ | en_US |
dc.subject.other | Geology - Iran | en_US |
dc.subject.other | Geochemistry - Iran | en_US |
dc.title | Geology, geochemistry and evolution of the Esfordi Phosphate - Iron Deposit, Bafq Area, Central Iran | en_US |
dc.type | Thesis | en_US |
dcterms.accessRights | open access | |
dcterms.rightsHolder | Jami, Morteza | |
dspace.entity.type | Publication | en_US |
unsw.accessRights.uri | https://purl.org/coar/access_right/c_abf2 | |
unsw.identifier.doi | https://doi.org/10.26190/unsworks/17736 | |
unsw.relation.faculty | Science | |
unsw.relation.originalPublicationAffiliation | Jami, Morteza, Biological, Earth & Environmental Sciences, Faculty of Science, UNSW | en_US |
unsw.relation.school | School of Biological, Earth & Environmental Sciences | * |
unsw.thesis.degreetype | PhD Doctorate | en_US |
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