Publication: Chlorite geothermometry applied to massive and oscillatory-zoned radiated Mn-rich chlorites in the Patricia Zn-Pb-Ag epithermal deposit (NE, Chile)
Loading...
Full text at PDC
Publication Date
2016
Authors
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Citations
Exportar
Abstract
Two textural types of chlorite are identified in the mineralised veins at the Patricia Zn-Pb-Ag epithermal ore deposit (NE, Chile): massive and oscillatory-zoned adiated chlorites. Three main stages of mineralisation have been defined in the Patricia deposit: (1) pre-ore stage, (2) base-metal stage which is divided into two substages: substage 2a and substage 2b and (3) post-ore stage. Both types of chlorite are classified as chamosite and occur coeval to the sphalerite precipitation during the substage 2a. Massive chlorite shows an average content of 33 wt.% FeO, 4.9 wt.% MnO, and 4 wt.% MgO. Oscillatory zoning in radiated chlorites consists of concentric bands with different contents on FeO (from 26.45 to 41.41 wt.%), MgO (from 1.7 to 5.44 wt.%) and MnO (from 1.7 to 9.32 wt.%). Four different chlorite geothermometers based on the system SiO2-Al2O3-FeO-MgO-H2O were applied to both types of chlorites. The temperature estimations are in agreement with temperatures data of fluid inclusions previously measured in sphalerite of the sub-stage 2a. Despite the high content in Mn of chlorites, the study confirms the applicability of the chlorite geothermometers without the knowledge of the Fe3+/Fe ratio in low-pressure paragenesis and its usefulness as an important tool for characterising the thermal conditions in epithermal ore deposits.