TY - JOUR
T1 - Hydrothermal altered serpentinized zone and a study of Ni-magnesioferrite-magnetite-awaruite occurrences in Wadi Hibi, Northern Oman Mountain
T2 - Discrimination through ASTER mapping
AU - Rajendran, Sankaran
AU - Nasir, Sobhi
N1 - Funding Information:
The authors are thankful to NASA Land Processes Distributed Active Archive Center User Services and USGS Earth Resources Observation and Science (EROS) Center ( https://LPDAAC.usgs.gov ) for providing the ASTER data. Thanks to Thomas Theye, Stuttgart University for microprobe analysis. The study was supported by Sultan Qaboos Internal grant IG/SCI/ETHS/12/02 . Authors are highly thankful to the Editor and anonymous reviewers of the journal for their valuable reviews and providing constructive comments and suggestions that have helped to present the work lucidly.
PY - 2014/10
Y1 - 2014/10
N2 - Economic important minerals and ore deposits are common in hydrothermal altered serpentinized zone. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite sensor is capable of discrimination of such hydrothermal mineralized zone and detection of hydrothermal altered minerals. In the present study, the hydrothermal altered serpentinized harzburgites of Wadi Hibi area of Northern Oman Mountains have been discriminated by using ASTER VNIR-SWIR spectral bands by image processing methods and the occurrences of Ni-magnesioferrite-magnetite-awaruite in the rocks are studied. The color composite RGB image developed using ASTER spectral bands 8, 4 and 1, mapped well the occurrence of weathered peridotites by pale green to dark blue in colors and discriminated the hydrothermally altered serpentinized rocks by pale brown to dark blue colors due to the strong absorption of OH and Mg-OH molecules that occurred in the serpentine minerals of the rocks in the study area. The ASTER band ratios 4/7, 4/1, and 2/3. ×. 4/3 RGB images studied are capable of discrimination of hydrothermal mineralized areas more clear by pale blue to purple colors due to the strong absorption of such hydroxyl bearing serpentine minerals. The studied image processing methods are evaluated by applying to the region of Wadi Sarami situated in the Semail ophiolite (Oman). In addition to that, the occurrence of serpentine minerals namely, lizardite and antigorite in the hydrothermally altered serpentinized region are detected qualitatively and quantitatively using Spectral Angle Mapper (SAM) supervised classification image processing method and studied.The interpreted images are verified in the field and checked for the occurrences of minerals including Ni-magnesioferrite, magnetite, pentlandite and awaruite and are confirmed through laboratory studies. Petrographic study of serpentinized harzburgites shows that the rocks consist predominantly of antigorite and lizardite serpentines, olivine and have the opaque minerals assemblage of Ni-magnesioferrite. +. magnetite. +. awaruite. +. pentlandite developed during serpentinization of the rock. The occurrences of such minerals are confirmed by XRD, electron microprobe analyses and spectral measurements in the laboratory.ASTER sensor proved its capability in discriminating the hydrothermal altered serpentinized zone and detecting the mineral occurrences and thus the study recommends the technique to the exploration geologists, scientists and mining geologists for mapping of such rocks and minerals in the similar arid region.
AB - Economic important minerals and ore deposits are common in hydrothermal altered serpentinized zone. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite sensor is capable of discrimination of such hydrothermal mineralized zone and detection of hydrothermal altered minerals. In the present study, the hydrothermal altered serpentinized harzburgites of Wadi Hibi area of Northern Oman Mountains have been discriminated by using ASTER VNIR-SWIR spectral bands by image processing methods and the occurrences of Ni-magnesioferrite-magnetite-awaruite in the rocks are studied. The color composite RGB image developed using ASTER spectral bands 8, 4 and 1, mapped well the occurrence of weathered peridotites by pale green to dark blue in colors and discriminated the hydrothermally altered serpentinized rocks by pale brown to dark blue colors due to the strong absorption of OH and Mg-OH molecules that occurred in the serpentine minerals of the rocks in the study area. The ASTER band ratios 4/7, 4/1, and 2/3. ×. 4/3 RGB images studied are capable of discrimination of hydrothermal mineralized areas more clear by pale blue to purple colors due to the strong absorption of such hydroxyl bearing serpentine minerals. The studied image processing methods are evaluated by applying to the region of Wadi Sarami situated in the Semail ophiolite (Oman). In addition to that, the occurrence of serpentine minerals namely, lizardite and antigorite in the hydrothermally altered serpentinized region are detected qualitatively and quantitatively using Spectral Angle Mapper (SAM) supervised classification image processing method and studied.The interpreted images are verified in the field and checked for the occurrences of minerals including Ni-magnesioferrite, magnetite, pentlandite and awaruite and are confirmed through laboratory studies. Petrographic study of serpentinized harzburgites shows that the rocks consist predominantly of antigorite and lizardite serpentines, olivine and have the opaque minerals assemblage of Ni-magnesioferrite. +. magnetite. +. awaruite. +. pentlandite developed during serpentinization of the rock. The occurrences of such minerals are confirmed by XRD, electron microprobe analyses and spectral measurements in the laboratory.ASTER sensor proved its capability in discriminating the hydrothermal altered serpentinized zone and detecting the mineral occurrences and thus the study recommends the technique to the exploration geologists, scientists and mining geologists for mapping of such rocks and minerals in the similar arid region.
KW - ASTER sensor
KW - Awaruite
KW - Ni-magnesioferrite
KW - Ophiolites
KW - Sultanate of oman
KW - Zone of serpentinization
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U2 - 10.1016/j.oregeorev.2014.03.016
DO - 10.1016/j.oregeorev.2014.03.016
M3 - Article
AN - SCOPUS:84900821001
SN - 0169-1368
VL - 62
SP - 211
EP - 226
JO - Ore Geology Reviews
JF - Ore Geology Reviews
ER -