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Liu L.,Changan University | Liu L.,Lanzhou AuriferouStone Mining Services Co. | Zhou J.,Changan University | Zhou J.,Lanzhou AuriferouStone Mining Services Co. | And 3 more authors.
Journal of Earth Science | Year: 2014

Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data covering the Jiafushaersu area in Xinjiang were used for mapping lithology and hydrothermal alteration. The study area situates at a potential mineralization zone in relation to small hypabyssal granodiorite or quartz monzonite intrusions along the margin of granitoid batholiths of Darbut foot wall. The false colour composition of bands 521 and the first three principal component analyses (PCA1, PCA2, PCA3) in RGB identify the lithological units and discriminate the small intrusions very well from the adjacent granitoid batholiths. PCA and spectral angle mapper (SAM) algorithm were employed to discriminate alteration minerals. The results indicate that the hydroxyl-bearing or ferric and less commonly carbonate types show good correlation with the quartz monzonite porphyry and aplite. Field verification led to finding of the Jiafushaersu molybdenum mineralization. The lithological and geochemical features imply that the molybdenum mineralization is close to the porphyry type. This study further verified that the foot wall of the Darbut suture could have served as a more important metallogenic district for the porphyry copper and molybdenum deposits. It is concluded that the ASTER data-based methods can be used as a powerful tool for small intrusion-type mineral resources targeting. © 2014 China University of Geosciences and Springer-Verlag Berlin Heidelberg.

Liu L.,Changan University | Liu L.,Lanzhou AuriferouStone Mining Services Co. | Zhou J.,Changan University | Zhou J.,Lanzhou AuriferouStone Mining Services Co. | And 3 more authors.
Journal of Earth Science | Year: 2014

The Beishan area has more than seventy mafic-ultramafic complexes sparsely distributed in the area and is of a big potential in mineral resources related to mafic-ultramafic intrusions. Many mafic-ultramafic intrusions which are mostly in small sizes have been omitted by previous works. This research takes Huitongshan as the study area, which is a major district for mafic-ultramafic occurrences in Beishan. Advanced spaceborne thermal emission and reflection radiometer (ASTER) data have been processed and interpreted for mapping the mafic-ultramafic complex. ASTER data were processed by different techniques that were selected based on image reflectance and laboratory emissivity spectra. The visible near-infrared (VNIR) and short wave infrared (SWIR) data were transformed using band ratios and minimum noise fraction (MNF), while the thermal infrared (TIR) data were processed using mafic index (MI) and principal components analysis (PCA). ASTER band ratios (6/8, 5/4, 2/1) in RGB image and MNF (1, 2, 4) in RGB image were powerful in distinguishing the subtle differences between the various rock units. PCA applied to all five bands of ASTER TIR imagery highlighted marked differences among the mafic rock units and was more effective than the MI in differentiating mafic-ultramafic rocks. Our results were consistent with information derived from local geological maps. Based on the remote sensing results and field inspection, eleven gabbroic intrusions and a pyroxenite occurrence were recognized for the first time. A new geologic map of the Huitongshan area was created by integrating the results of remote sensing, previous geological maps and field inspection. It is concluded that the workflow of ASTER image processing, interpretation and ground inspection has great potential for mafic-ultramafic rocks identifying and relevant mineral targeting in the sparsely vegetated arid region of northwestern China. © China University of Geosciences and Springer-Verlag Berlin Heidelberg 2014.

Yin F.,Changan University | Liu L.,Changan University | Liu L.,Lanzhou AuriferouStone Mining Services Co. | Zhang J.-R.,Changan University | And 2 more authors.
Acta Geoscientica Sinica | Year: 2014

The small acid-intermediate intrusion is often ignored because of its small size and the large distance between two adjacent survey routes for geological mapping. This has seriously restricted the discovery of the relevant mineralization. During the mineral exploration in Xiemisitai area of west Junggar Basin, Xinjiang, a remote sensing-dominated method was used for targeting of small intrusion-related deposits. First, ETM+ data were used for reconnaissance of small intrusions. In the selected area, ETM+ data and CBERS-02B HR were fused to identify small intrusions. Then, remote sensing anomalies were delineated by using the principal component analysis. The targets were selected based on synthetic analysis of remote sensing results, geological data and geochemical anomalies. Fourteen small potash-feldspar granites and three hornblende biotite granites were interpreted and most of these small intrusions were confirmed in the field. Five Cu and Au mineralization spots were discovered for the first time, which confirmed the validity of this method. These methods are recommended for lithologic mapping and small intrusion-related mineral resources targeting in the sparse vegetation arid regions of northwestern China.

Liu L.,Changan University | Liu L.,Lanzhou AuriferouStone Mining Services Co. | Zhou J.,Changan University | Zhou J.,Lanzhou AuriferouStone Mining Services Co. | And 4 more authors.
Remote Sensing | Year: 2013

The Xiemisitai area, West Junggar, Xinjiang, China, is situated at a potential copper mineralization zone in association with small granitic intrusions. In order to identify the alteration zones and mineralization characteristics of the intrusions, Landsat Enhanced Thematic Mapper (ETM+) and Quickbird data of the study area were evaluated in mapping lithological units, small intrusions, and alteration zones. False color composites of the first principal component analyses (PCA1), PCA2, and PCA4 in red (R), green (G), and blue (B) of the ETM+ image, and relevant hue-saturation-intensity (HSI) color model transformations, were performed. This led to the identification of lithologic units and discrimination of granitic intrusions from wall-rocks. A new geological map was generated by integrating the remote sensing results with two internally published local geologic maps and field inspection data. For the selected region, false color composites from PCA and relevant HSI-transformed images of the Quickbird data delineated the details of small intrusions and identified other unknown similar intrusions nearby. Fifteen separate potash-feldspar granites and three separate hornblende biotite granites were identified using ETM+ and Quickbird data. The principal component analysis-based Crosta technique was employed to discriminate alteration minerals. Some of the mapped alteration zones using the Crosta technique agreed very well with the known copper deposits. Field verification led to the discovery of three copper mineralizations and two gold mineralizations for the first time. The results show that the PCA and HSI transformation techniques proved to be robust in processing remote sensing data with moderate to high spatial resolutions. It is concluded that the utilized methods are useful for mapping lithology and the targeting of small intrusion-type mineral resources within the sparsely vegetated regions of Northwest China. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

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