Reanalysis of the existing regional geochemical data around the Sakatti Ni-Cu-PGE target, Sodankylä, Finland

• Main Author: Kääriäinen, Kristiina
• Other Authors: Helsingin yliopisto, Matemaattis-luonnontieteellinen tiedekunta, Geotieteiden ja maantieteen laitos, University of Helsinki, Faculty of Science, Department of Geosciences and Geography, Helsingfors universitet, Matematisk-naturvetenskapliga fakulteten, Institutionen för geovetenskaper och geografi
• Format: Master Thesis
• Language: English
• Published: Helsingfors universitet 2016
• Subjects: Geology; Geologia; Geologi; Sodankylä; Lapland
• Online Access: http://hdl.handle.net/10138/169088

In 2009, mining company Anglo American found a significant Ni-Cu-PGE deposit in Sodankylä, Finnish Lapland. The deposit is located underneath Viiankiaapa mire and has later been named Sakatti. During the 1970s and 1980s, the Geological Survey of Finland carried out a targeting till geochemistry program that covered most of Finnish Lapland. The ore potential of Viiankiaapa was not recognized in the original research report from the area. The targeting till geochemistry dataset is an example of the vast amount of existing geological data that is publicly available but has not been widely used. The targeting till geochemistry results from Viiankiaapa area were reanalysed using modern methods to find out whether they contain any indications of the Sakatti deposit. Principal component analysis, k-means clustering and element ratios formed an effective combination to recognize the potentially mineralized samples. Self-organizing maps would have benefited from more detailed data. All methods were used first for the targeting till geochemistry data and then for combined datasets that included information about the Sakatti discovery. Clear indications of the Sakatti deposit were found in till samples adjacent to the known ore outcrops, where the samples had high Ni concentration and their element ratios were similar to the ore. The most significant limitation of the targeting till geochemistry data is the lack of stratigraphic information. The problem could be partly overcome by using recent stratigraphical interpretations from a different study. Even considering the weaknesses of the targeting till geochemistry dataset, results from Viiankiaapa show that it contains valuable exploration potential. The dataset could be used in ore prospecting surveys elsewhere to point out the most promising targets. Vuonna 2009 kaivosyhtiö Anglo American löysi merkittävän Ni-Cu-PGE -esiintymän Sodankylästä, Suomen Lapista. Esiintymä sijaitsee Viiankiaavan alla ja on myöhemmin saanut nimen Sakatti. Geologian tutkimuskeskus toteutti ...