Determination of trace elements in iron-manganese oxide coatings by laser ablation ICP-MS for environmental monitoring/mineral exploration

• Main Author: Huelin, Sheldon Richard
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2005
• Subjects: Betts Cove; Tilt Cove; Newfoundland
• Online Access: https://research.library.mun.ca/10702/; https://research.library.mun.ca/10702/1/Huelin_SheldonRichard.pdf

Iron-manganese oxide coatings can form on a wide range of geologic samples and they have the inherent geochemical ability to adsorb elements and thus potentially act as tools for mineral exploration and environmental monitoring. In this study the concentrations of elements present in Fe-Mn oxide coatings were determined using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LAM-ICP-MS). The potential Fe-Mn oxide coatings for environmental monitoring was assessed at three study sites located on the island of Newfoundland. Additionally, annual accretion at one study site was also examined to further understand coating accretion as a function of time. -- Useful analytical results were obtained using a data normalisation scheme which set the sum of MnO₂ + Fe₂O₃ in the coating to 100%. Quantification of an internal standard was investigated using an Electron Microprobe and Scanning Electron Microscope. However this was not successful because of sample heterogeneity and the thinness of the coating. The acquired samples underwent a simple sample preparation procedure, and were analysed using optimised operating conditions. -- For the mineral exploration and environmental monitoring aspect of this study, four study locations with a wide range of sample sites were selected; Tilt Cove, Betts Cove, Robinsons River, and Rennies River. Water samples were collected along with the Fe-Mn oxide coatings. The waters were analysed for dissolved oxygen, pH, conductivity, temperature, and 46 elements using ICP-MS. Multivariate statistics, in the form of Principal Component Factor Analysis (PCFA) was performed on the data. Graphical display of the Factor scores from the PCF A produced sample groupings that were related to both geologic and environmental inputs. For the water PCFA, variable loadings were related to the local geology and environmental conditions along with the affinity of the element. The loading of variables in each Factor for the Fe-Mn oxide coating data was related to the adsorption of the element either ...