New Insights for the Formation of Kiruna-Type Iron Deposits by Immiscible Hydrous Fe-P Melt and High-Temperature Hydrothermal Processes: Evidence from El Laco Deposit

Abstract

Research Article| February 01, 2019 New Insights for the Formation of Kiruna-Type Iron Deposits by Immiscible Hydrous Fe-P Melt and High-Temperature Hydrothermal Processes: Evidence from El Laco Deposit Qiuhong Xie; Qiuhong Xie 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Search for other works by this author on: GSW Google Scholar Zhaochong Zhang; Zhaochong Zhang 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China †Corresponding author: e-mail, zczhang@cugb.edu.cn Search for other works by this author on: GSW Google Scholar Tong Hou; Tong Hou 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Search for other works by this author on: GSW Google Scholar Zhiguo Cheng; Zhiguo Cheng 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Search for other works by this author on: GSW Google Scholar Eduardo Campos; Eduardo Campos 2Departamento de Ciencias Geológicas, Universidad Católica del Norte, Antofagasta 1240000, Chile Search for other works by this author on: GSW Google Scholar Zhenchao Wang; Zhenchao Wang 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Search for other works by this author on: GSW Google Scholar Xianghui Fei Xianghui Fei 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Search for other works by this author on: GSW Google Scholar Author and Article Information Qiuhong Xie 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Zhaochong Zhang 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Tong Hou 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Zhiguo Cheng 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Eduardo Campos 2Departamento de Ciencias Geológicas, Universidad Católica del Norte, Antofagasta 1240000, Chile Zhenchao Wang 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China Xianghui Fei 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China †Corresponding author: e-mail, zczhang@cugb.edu.cn Publisher: Society of Economic Geologists Accepted: 11 Dec 2018 First Online: 28 Feb 2019 Online Issn: 1554-0774 Print Issn: 0361-0128 © 2019 Economic GeologyEconomic Geology Economic Geology (2019) 114 (1): 35–46. https://doi.org/10.5382/econgeo.2019.4618 Article history Accepted: 11 Dec 2018 First Online: 28 Feb 2019 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Qiuhong Xie, Zhaochong Zhang, Tong Hou, Zhiguo Cheng, Eduardo Campos, Zhenchao Wang, Xianghui Fei; New Insights for the Formation of Kiruna-Type Iron Deposits by Immiscible Hydrous Fe-P Melt and High-Temperature Hydrothermal Processes: Evidence from El Laco Deposit. Economic Geology 2019;; 114 (1): 35–46. doi: https://doi.org/10.5382/econgeo.2019.4618 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEconomic Geology Search Advanced Search Abstract The world-renowned Pliocene El Laco iron deposit in northern Chile is the youngest and the best-preserved Kiruna-type deposit in the world. The genesis of the El Laco Kiruna-type iron deposit—i.e., whether it is magmatic or hydrothermal in origin—is a long-standing controversy. The interstitial Fe-P phase lined by early formed magnetite crystals observed in massive ores at El Laco is morphologically and geochemically consistent with that produced by recent immiscible experiments, confirming that the massive magnetite ores were products of complete solidification of an iron-rich mush comprising early crystallized magnetite and an interstitial immiscible Fe-P melt. The hydrothermal features in geochemistry of massive magnetite are similar to the features of magnetite in altered andesites, implying a superimposed hydrothermal process. The occurrence of melt inclusions with high homogenization temperatures (>700°C) hosted by the apatite in Cristales Grandes ores indicates that the veined ores formed shortly after the massive ores genetically related to the magmatic system. Some vesicles in the massive ores and the magnetite scoriae, previously interpreted as compelling evidence of volcanic structures, are demonstrated to be the residual pore spaces formed after interstitial phases between magnetite grains were removed by postmagmatic hydrothermal fluids and the accumulated debris eroded from massive ores with minor altered andesites, respectively. Thus, we propose a two-step genetic model in which massive ores resulted from magmatic processes and then were modified by subsequent magmatic-hydrothermal alteration. This model could be applied to the metallogenesis of most Kiruna-type iron deposits. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.