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LI Ruibao PEI Xianzhi LI Zhuochen SUN Yu PEI Lei CHEN Guochao CHEN Youxin LIU Chengjun WEI Fanghui 《《地质学报》英文版》2013,87(2):333-345
The Helegangnaren feldspar granite exposed in the eastern part of East Kunlun, is characterized by high concentrations of SiO2 and alkaline, low abundances of Fe, Mg and Ca, metaluminous-weak peraluminous. Trace elements analysis shows that the granite is depleted extremely in Ba, Sr and Eu, and rich in some large-ion lithophile elements and high field strength elements. Besides, the granite has high Ga contents, the values of 104(Ga/Al) vary from 2.50 to 2.77, which is mainly greater than the lower limit of A-type granites (2.6), and is higher than the I- and S-type granites’ average (2.1 and 2.28, respectively). Rare earth element (REE) is characterized by relatively high fractionations of light REE (LREE) and heavy REE (HREE) (LREE/HREE=9.3–13.60, (La/Yb)N=10.92–18.02), pronounced negative Eu anomalies (δEu=0.08–0.13), and exhibits right-dipping gull pattern. Major elements, rare elements and trace elements features show the granite is ascribed to A-type granite and A2 subtype in tectonic genetic type. They are plotted into post-collision or within-plate area in a variety of tectonic discriminations. Geological and geochemical data comprehensively suggest that the granite is formed in a post-collision extensive tectonic setting. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) zircon U-Pb dating yields a weighted mean age of 425?Ma, belonging to Middle Silurian, which is similar to the age of the post-collision geological events in the region. The differences of magmatic rocks in formation age, rocks assemblage and rocks series systematically indicate that the regional tectonic stress regime in the East Kunlun orogenic belt experienced a major transformation from compress to extension in Middle Silurianin, and the Helegangnaren feldspar granite intruded in the early stage of tectonic transformation. 相似文献
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Because of the increasing public awareness of the greenhouse effect, geological emissions of methane (GEM) have gained more
attention. The Intergovernmental Panel on Climate Change included GEM in the natural sources of methane category in the Fourth
Assessment Report in 2007. The methane flux from mud volcanoes (MVs) is the second leading source within GEM. However, given
that gas flux from MVs has been measured directly only in Sicily and Azerbaijan, the global methane estimation is still a
conservative assumption based on limited data. The behavior of MV activities is seldom reported. This study attempts to estimate
annual methane emissions through MVs by using a video recorder to record MV activities along the Chishan Fault and determining
the bubble size and flux rate of each MV. Observation results, after a 1 year observation period, indicate that the annual
emissions of the 19 MVs along the Chishan Fault are 0.1–0.2% of the global methane flux from MVs, highlighting that the methane
emission from these MVs should not be neglected. In addition, the continuous monitoring of a particular MV disclosed periodic
characteristics of MV activities. These results manifest the spatial and temporal variations of MV activities along the Chishan
Fault. The spatial variations are related to the extensional kinematics of the Chishan fault, while the temporal variation
relates to the earth-tide-related MV activities. The estimated annual methane emissions from the study are far more than those
of previous studies and are still considered conservative. Results of this study may provide valuable information for researchers
attempting to estimate the quantity of GEM. 相似文献
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利用干馏后的油页岩灰渣,湿法提取氧化铝作为发光材料基质,经采用高温固相法合成 CaAl2O4 : Eu3 + ,R + ( R = Li,Na,K,Rb) 荧光粉。最佳合成条件为: 烧结温度1 200 ℃,烧结时间3 h,助熔剂加入量3 wt%,激活离子配比3 mol%; 实验发现辅助激活离子为Li + 时,CaAl2O4 : Eu3 + , Li + 的发光强度最强。样品荧光光谱分析结果表明,发射光谱在615 nm 处出现强谱峰,归属为Eu3 + 的5D0→7F2 跃迁辐射。 相似文献
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