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Fu W.,Guilin University of Technology | Fu W.,Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration | Yang J.,Guilin University of Technology | Yang J.,University of Windsor | And 7 more authors.
Journal of Asian Earth Sciences | Year: 2014

To evaluate the lateritization process and supergene Ni enrichment in the tropical rainforest, a well developed laterite profile over the serpentinite in the Kolonodale area of East Sulawesi, Indonesia, has been investigated using field geology methods, mineralogical and geochemical techniques. Three lithostratigraphic horizons over the bedrock are distinguished from bottom to top: the saprolite horizon, the limonite horizon, and the ferruginous cap. In general, the profile is characterized by (1) a depth-related pH ranging from 5.56 to 8.56, with a higher value in the saprolite horizon and a lower value in the ferruginous cap, (2) a highly variable organic matter concentration from 1.11% to 4.82%, showing a increasing trend from bottom to top, (3) a progressive mineral assemblage transition from the silicate mineral dominant (mainly serpentine) to the Fe-oxyhydroxide dominant (mainly goethite), and (4) a typical laterite geochemical pattern with an increase of Fe, Al, Mn, Cr and Ti but a decrease of Mg, Ca, Na and K upward from the bedrock. The highest concentration of Ni (up to 11.53%NiO) occurs in the saprolite horizon, showing nearly 40. times richer compared to the bedrock. The mineral evolution during the lateritization process shows various paths from the primary minerals to altered minerals, which is integrally affected by the nature of the primary minerals and environmental conditions. Garnierite, as a significant ore mineral formed by the secondary precipitation processes in the study profile, is identified as a mixture of talc- and serpentine-like phases. The mass-balance calculation reveals that there are diversified elemental behaviors during the serpentinite lateritization under the rainforest conditions. In particular, Ni, as the ore-forming element in the laterite profile, is associated closely with the pH environment, organic matter concentration and mineral evolution during the lateritization process. The findings of the present study support a four-stage evolutional model for the lateritization process: the ferruginous saprolite development (stage I), the limonite development (stage II), the silicate saprolite and ferruginous cap development (stage III), and the precipitation of secondary minerals (stage IV). Due to this multistage process, there is a progressive Ni-enrichment in the laterite profile. © 2014 Elsevier Ltd.

Kang Z.,Guilin University of Technology | Kang Z.,Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration | Fu W.,Guilin University of Technology | Tian G.,Guilin University of Technology | Tian G.,Chinese People's Armed Police forces Academy
Geological Bulletin of China | Year: 2015

The evolution of Neo-Tethys and associated magmatism during Mesozoic has become a topic of much debate in the basic study of the Tibetan Plateau. Voluminous Mesozoic volcano-sedimentary sequences corresponding to the subduction of the Neo-Tethys crop out on the southern margin of Lhasa Block. The systematic study of these volcano-sedimentary sequences is of great importance in understanding the evolution of the Neo-Tethys and the Lhasa Block. With the volcano-sedimentary sequences of the Yeba Formation, the Sangri Group and the Danshiting Formation exposed in Sangri County as the study object, the authors carried out zircon LA-ICP-MS and SHRIMP dating and geochemical analysis for the volcanic rocks. In combination with the data available, the authors hold that both the Bima Formation (189.0±3.0~195.0±3.0Ma) in the upper part of the Sangri Group and the Yeba Formation (174.2±3.6~192.7±1.3Ma) were formed in the early Jurassic. Furthermore, the volcanic rocks of the Bima and Yeba formations display similar geochemical characteristics, and thus might have been formed in the same tectonic setting. It is suggested that they are arc-related calc-alkaline volcanic rocks. Therefore, the Bima Formation could be separated from the Sangri Group, and correlated with the Yeba Formation. In contrast, the Mamuxia Formation (99.9±0.7~136.5±1.7 Ma) in the upper part of the Sangri Group was much younger than the Bima Formation, and belongs to Lower Cretaceous strata. The Mamuxia Formation has geochemical characteristics of adakite, and should be regarded as a single independent formation. The Danshiting Formation was formed at 93.7±1.2 Ma, belonging to Upper Cretaceous, and should also be classified as an independent formation. ©, 2015, Science Press. All right reserved.

Yang Q.,Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration | Yang Q.,Guilin University of Technology | Wang Y.-X.,Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration | Wang Y.-X.,Guilin University of Technology | And 4 more authors.
Wutan Huatan Jisuan Jishu | Year: 2013

The power spectrum method is one of the conventional methods in calculating the top and bottom depths of the magnetic anomalies. The result may be, however, affected by some factors and lead to a wrong interpretation. By using higher-order derivatives, this paper uses the power spectrum to calculate the top and bottom depths of magnetic anomalies to analyze the factors.

Wei F.,Guilin University of Technology | Wei F.,Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration | Xiao-Rong H.,Guilin University of Technology | Hong-Yi C.,Guilin University of Technology | And 3 more authors.
Applied Mechanics and Materials | Year: 2013

To understand the nickel supergene enrichment mechanism in the lateritic process, we have conducted a preliminary analysis of the micro-morphology and micro-area chemical characteristics of the nickel-carrying minerals of garnierite, sampled from the Kolonodale area of Sulawesi Island in Indonesia. The SEM + EDS analysis shows that, the main nickel-carrying minerals in garnierite are serpentine and talc. The micro-morphology of the talc is fragmented and in piling structure. The micro-morphology of serpentine manifested tubular, fibrous, plate-like and other morphologies, showing the staggered and twisted, mesh-cross and sheet-interwoven structures, etc. The EPMA line scan analysis shows that the mineral types of garnierite samples are mainly of serpentine, talc, olivine and pyroxene debris, containing small amount of quartz, chrome spinel, etc. The Ni content varies a lot in the different minerals, and the nickel-carrying level sorting from high to low is: talc> secondary serpentine> iddingsite > residual serpentine> residual spinel> secondary quartz. © (2013) Trans Tech Publications, Switzerland.

Yang M.-L.,Guilin University of Technology | Fu W.,Guilin University of Technology | Fu W.,Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration | Wang B.-H.,Guilin University of Technology | And 4 more authors.
Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis | Year: 2015

The silicate nickel ores developed in the lateritic nickel deposit, from Kolonodale, Sulawesi Island, Indonesia, and Yuanjiang, Yunnan province, China, were selected for the present study. The X-ray diffraction and Fourier infrared spectra were used to analyze the mineralogical attribute of laterite nickel ores from two different places. The results show that these two different silicate nickel ores have unique infrared spectra characteristics individually, which contributes to the ore classification. The silicate nickel ores from Kolonodale deposit, Indonesia, can be classified as the serpentine type, the montmorillonite+serpentine type, and the garnierite type. While, the silicate nickel ores from Yuanjiang deposit, China, can be classified as the serpentine type and the talc+serpentine type. Moreover, the mineral crystallinity of Yuanjiang nickel ores is generally better than Kolonodale nickel ores. According to the advantage of infrared absorption spectra in distinguishing mineral polytypes, it can be determined that lizardite is the main mineral type in the silicate nickel ores of the two deposits, and there is no obvious evidence of chrysotile and antigorite's existence. The characteristic of infrared absorption spectra also shows that frequency change of OH libration indicates Ni (Fe) replacing Mg in the serpentine type nickel-bearing mineral, that is, OH libration of serpentine moves to higher frequency, with the proportion of Ni (Fe) replacing Mg increasing. ©, 2015, Science Press. All right reserved.

Fu W.,Guilin University of Technology | Fu W.,Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration | Yang M.L.,Guilin University of Technology | Guo Q.H.,Guangdong Geological Prospecting Bureau | And 3 more authors.
Advanced Materials Research | Year: 2013

A preliminary study on the micro-structure of a special sericite-jade material has been carried out by using the XRD and SEM methods. By XRD analysis, the 2M1 type sericite is identified as the main mineral composition of the white-colored, yellow-colored and green-colored jade. Quartz, as the secondary mineral, is also common in the green-colored jade. However, the dominant mineral composition of the black-colored jade is chlorite. SEM analysis reveals both the micro-morphology of the jade-forming minerals and the micro-structure of the mineral aggregates are various, which have significant relationships with the Guangning jade quality. Minuscular mineral grains and compact micro-structure make jade materials exquisite. Conversely, large mineral grains and the loose micro-structure make jade materials more rougher. © (2013) Trans Tech Publications, Switzerland.

Fu W.-C.,Guilin University of Technology | Kang Z.-Q.,Guilin University of Technology | Kang Z.-Q.,Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration | Kang Z.-Q.,Curtin University Australia | Pan H.-B.,Guilin University of Technology
Geological Bulletin of China | Year: 2014

Located in the southern part of Gangdise belt, the Linzizong Group volcanic rocks are regarded as the magmatic response to the continental collision between India and Asia, which is essentially important in understanding the evolutionary history of the Gangdise belt. The present research is only focused on central-western part of Gangdese belt, while the research on the western part is very insufficient. The authors conducted for the first time a systematic study of geochronology and major and trace element geochemistry of the Linzizong Group volcanic rocks in Shiquan River area in western Gangdise belt. The results indicate that the Nianbo Formation is of the calc-alkalic and high-potassic calc-alkalic series and is composed mostly of basaltic andesite, andesite and rhyolite, whereas the Pana Formation is of the high-potassic calc-alkalic to Shoshonite series with rhyolite. The Linzizong Group volcanic rocks in Shiquan River area are enriched in Rb, Th and U and depleted in Nb, Ta, Ti, Sr and Ba, which is similar to characteristics of central-eastern Gangdise belt, indicating the arc-related volcanics. The LA-ICP-MS zircon U-Pb age of Pana Formation in Shiquan River area is 53.9±0.5Ma, which is older than that of central-eastern Gangdise belt. The results combined with previous researches show that the initial collision between India and Asia continent took place earlier in western Gangdise belt but late in central-eastern Gangdise belt.

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