Economic potential of potassic feldpar-rich gneisses in Tysfjord/ Hamarøy, northern Norway

• Main Author: Karlsen, Tor Arne
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2000
• Subjects: FELTSPAT; GNEIS; PREKAMBRIUM; RESSURSKARTLEGGING; Norway; Narvik; Tysfjord; Hamarøy; Ulsvåg; Northern Norway
• Online Access: https://hdl.handle.net/11250/2674211

Potassic feldspar gneiss in the Tysfjord\/Hamarøy area may be potential resource for future exploitation. The rock consists primarily of microcline (up to 84%) and quartz (up to 35%) together with small amounts of plagioclase (1-12%), commonly albite. Accessory minerals include epidote, micas and magnetite. Six deposits have been indicated by mapping. All are situated within a supracrustal suite of Precambrian age (2500-2100 Ma) dominated by a feldspathic gneiss. The quality of the rocks is largely dependent on the texture and grain size, as a fine grain size and complex grain boundaries make separation of the different minerals difficult. 49535