Hydrothermal mineral alteration patterns in the Mount Isa Inlier revealed by airborne hyperspectral data

Laukamp, C., Cudahy, T., Thomas, M., Jones, M., Cleverley, J.S., and Oliver, N.H.S. (2011) Hydrothermal mineral alteration patterns in the Mount Isa Inlier revealed by airborne hyperspectral data. Australian Journal of Earth Sciences, 58 (8). pp. 917-936.

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High-resolution mineral maps derived from hyperspectral imaging (4.5 m pixel) enable the recognition of various types of hydrothermal alteration and the identification of fluid pathways. Airborne hyperspectral images from the Eastern Fold Belt of the Mount Isa Inlier were tested as a new tool for the detection of Fe-oxide Cu–Au (IOCG) related alteration. Four different types of hydrothermal alteration were identified with the hyperspectral mineral maps: (1) Metasomatic 1: white mica mineral maps show the spatial distribution of regional sodic–calcic alteration in metasedimentary successions of the Soldiers Cap Group in the Snake Creek Anticline. (2) Metasomatic 2: alteration zonation is evident from albitised granites assigned to the Williams–Naraku Suite along the Cloncurry Fault. These show characteristic absorption features in the shortwave infrared range (SWIR) which are depicted on the white mica mineral maps (white mica composition, white mica content, white mica crystallinity index). Alteration zonation in gabbros of the Cloncurry District was detected by a combination of MgOH and Fe2+ mineral maps (MgOH content, MgOH composition, amphibole/chlorite and Fe2+ and MgOH) combined with white mica mineral maps (white mica composition and white mica content). (3) Fluid channels 1: major fault zones, such as the Mt Dore fault zone in the Selwyn Corridor, are interpreted as important fluid pathways, where gradual changes in the mineral chemistry are highlighted with mineral maps (e.g. white mica content, white mica composition, white mica crystallinity index). (4) Fluid channels 2: MgOH and Fe2+ mineral maps were used to map breccia pipes in the northern Cloncurry District north of the Saxby Granite (Suicide Ridge). The MgOH and Fe2+ mineral maps were also used to distinguish various mafic rocks from amphibolites, which are host rocks for some of the IOCG deposits in the Eastern Fold Belt (e.g. Mount Elliott), and calcsilicate breccias pipes (e.g. Suicide Ridge).

Item ID: 20803
Item Type: Article (Research - C1)
ISSN: 1440-0952
Keywords: hydrothermal, alteration patterns, Mount Isa Inlier, hyperspectral data
Date Deposited: 12 Mar 2012 02:45
FoR Codes: 04 EARTH SCIENCES > 0404 Geophysics > 040403 Geophysical Fluid Dynamics @ 50%
04 EARTH SCIENCES > 0402 Geochemistry > 040201 Exploration Geochemistry @ 50%
SEO Codes: 84 MINERAL RESOURCES (excl. Energy Resources) > 8401 Mineral Exploration > 840199 Mineral Exploration not elsewhere classified @ 100%
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