The major element, trace element and Nd-Sr isotopic composition of Cenozoic basaltic volcanic rocks from the Maguan area, eastern Tibet, indicates that the volcanic rocks are enriched in alkalis, especially K (K-2O up...The major element, trace element and Nd-Sr isotopic composition of Cenozoic basaltic volcanic rocks from the Maguan area, eastern Tibet, indicates that the volcanic rocks are enriched in alkalis, especially K (K-2O up to {3.81%}) and depleted in Ti (TiO-2={1.27%}-{2.00%}). These rocks may be classified as two groups, based on their Mg+# numbers: one may represent primary magma (Mg+# numbers from 68 to 69), and the other, the evolved magma (Mg+# numbers from 49 to 57). Their REE contents are very high (∑REE={155.06}-{239.04}μg/g). Their REE distribution patterns are of the right-inclined type, characterized by LREE enrichment [(La/Yb)-N={12.0}-{19.2}], no Ce anomaly (Ce/Ce+*={1.0}), and weak negative Eu anomaly (Eu/Eu+*={0.9}). The rocks are highly enriched in Rb, Sr and Ba ({59.5}-{93.8} μg/g, 732-999 μg/g, and 450-632 μg/g, respectively), high in U and Th ({1.59}-{2.31} μg/g and {4.73}-{8.16} μg/g, respectively), and high in Nb, Ta, Zr and Hf (70-118 μg/g, {3.72}-{5.93} μg/g, 215-381 μg/g, and {5.47}-{9.03} μg/g, respectively). In the primitive mantle-normalized incompatible element spidergram, Nb, Ta, Zr, Hf and P show positive anomalies, whereas Ba, Ti and Y show negative anomalies. The {{}+{87}Sr/+{86}Sr} ratios range from {0.704029} to {0.704761}; {{}+{143}Nd/+{144}Nd} from {0.512769} to {0.512949}; and εNd from {+2.6} to {+6.1}. These geochemical features might suggest that the potential source of the basaltic high-K volcanic rocks in the Maguan area is similar to the OIB-source mantle of Hawaii and Kergeulen volcanic rocks.展开更多
The major elements, trace elements and Nd-Sr isotopic composition of Cenozoic high-K igneous rocks and mafic deep-derived enclaves from the Liuhe-Xiangduo area, eastern Tibet, indicate the high-K igneous rocks are cha...The major elements, trace elements and Nd-Sr isotopic composition of Cenozoic high-K igneous rocks and mafic deep-derived enclaves from the Liuhe-Xiangduo area, eastern Tibet, indicate the high-K igneous rocks are characterized as being enriched in Ca (CaO={1.20%}-{8.80%}), alkali (Na-2O+K-2O={3.47%}-{10.65%}), especially K (K-2O up to {5.96%}) and depleted in Ti (TiO-2={0.27%}-{1.50%}). Their REE contents are very high (REE={91.29}-{231.11} μg/g). Their REE distribution patterns are of the right-inclined type, characterized by intense LREE enrichment [(La/Yb)-N={7.44}-{15.73}]. The rocks are distinctly enriched in Rb, Sr and Ba ({46.3}-316 μg/g, 349-1220 μg/g and 386-2394 μg/g, respectively), high in U and Th ({1.17}-{8.10} μg/g and {2.58}-{27.0} μg/g, respectively), moderate in Zr and Hf ({87.5}-241 μg/g and {2.83}-{7.52} μg/g, respectively), and depleted in Nb and Ta ({4.81}-{16.8} μg/g and {0.332}-{1.04} μg/g, respectively). In the primitive mantle-normalized incompatible element spidergram, U, K, Sr and Hf show positive anomalies, whereas Th, Nb, Ta, P, and Ti show negative anomalies. The rocks are strongly depleted in Cr and Ni ({21.4}-1470 μg/g and {7.79}-562 μg/g, respectively), and their transition element distribution curves are obviously of type-W. The ({{}+{87}Sr/+{86}Sr)-i} ratios range from {0.704184} to {0.707539}; ({{}+{143}Nd}/{{}+{144}Nd)-i} from {0.512265} to {0.512564}; and ε-{Nd}(t) from {-6.3} to {-0.4}. These geochemical features might suggest that the potential source of the high-K igneous rocks in the Liuhe-Xiangduo area is similar to the EM2, which may be similar to the material enriched K that is located under the crust-mantle mixed layer. The mafic deep-derived enclaves in the high-K igneous rocks belong to chance xenoliths. Their ({{}+{87}Sr/+{86}Sr)-i} ratios range from {0.706314} to {0.707198}; ({{}+{143}Nd}/{{}+{144}Nd)-i} from {0.512947} to {0.513046}; and ε-{Nd}(t) from {+7.0} to {+9.0}. These geochemical features might indicate that the enclaves probably came from the depleted mantle. The P-T conditions of the enclaves also showed that the enclaves are middle-lower crust metamorphic rocks, which were accidentally captured at 20-50 km level by rapidly entrained high-K magma, whose source is over 50 km in depth.展开更多
The kinetics of liquid-phase hydrogenation of toluene catalyzed by MlNi5 was studied by investigating the influences of the reaction temperature and pressure on the mass transfer-reaction processes inside the slurry. ...The kinetics of liquid-phase hydrogenation of toluene catalyzed by MlNi5 was studied by investigating the influences of the reaction temperature and pressure on the mass transfer-reaction processes inside the slurry. The results show that the reaction rate accelerates when the reaction temperature increases, and reaches its maximum at about 490 K, but if temperature is higher than 510 K, the reaction rate decreases rapidly. The whole reaction process is controlled by the reaction at the surface of the catalyst particles. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particle can be neglected. The apparent reaction rate is zero order for toluene concentration and first order for hydrogen concentration in the liquid phase. The kinetic model is obtained. The kinetic model fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of MlNi5-toluene slurry system is 41.01 kJ·mol-1.展开更多
文摘The major element, trace element and Nd-Sr isotopic composition of Cenozoic basaltic volcanic rocks from the Maguan area, eastern Tibet, indicates that the volcanic rocks are enriched in alkalis, especially K (K-2O up to {3.81%}) and depleted in Ti (TiO-2={1.27%}-{2.00%}). These rocks may be classified as two groups, based on their Mg+# numbers: one may represent primary magma (Mg+# numbers from 68 to 69), and the other, the evolved magma (Mg+# numbers from 49 to 57). Their REE contents are very high (∑REE={155.06}-{239.04}μg/g). Their REE distribution patterns are of the right-inclined type, characterized by LREE enrichment [(La/Yb)-N={12.0}-{19.2}], no Ce anomaly (Ce/Ce+*={1.0}), and weak negative Eu anomaly (Eu/Eu+*={0.9}). The rocks are highly enriched in Rb, Sr and Ba ({59.5}-{93.8} μg/g, 732-999 μg/g, and 450-632 μg/g, respectively), high in U and Th ({1.59}-{2.31} μg/g and {4.73}-{8.16} μg/g, respectively), and high in Nb, Ta, Zr and Hf (70-118 μg/g, {3.72}-{5.93} μg/g, 215-381 μg/g, and {5.47}-{9.03} μg/g, respectively). In the primitive mantle-normalized incompatible element spidergram, Nb, Ta, Zr, Hf and P show positive anomalies, whereas Ba, Ti and Y show negative anomalies. The {{}+{87}Sr/+{86}Sr} ratios range from {0.704029} to {0.704761}; {{}+{143}Nd/+{144}Nd} from {0.512769} to {0.512949}; and εNd from {+2.6} to {+6.1}. These geochemical features might suggest that the potential source of the basaltic high-K volcanic rocks in the Maguan area is similar to the OIB-source mantle of Hawaii and Kergeulen volcanic rocks.
文摘The major elements, trace elements and Nd-Sr isotopic composition of Cenozoic high-K igneous rocks and mafic deep-derived enclaves from the Liuhe-Xiangduo area, eastern Tibet, indicate the high-K igneous rocks are characterized as being enriched in Ca (CaO={1.20%}-{8.80%}), alkali (Na-2O+K-2O={3.47%}-{10.65%}), especially K (K-2O up to {5.96%}) and depleted in Ti (TiO-2={0.27%}-{1.50%}). Their REE contents are very high (REE={91.29}-{231.11} μg/g). Their REE distribution patterns are of the right-inclined type, characterized by intense LREE enrichment [(La/Yb)-N={7.44}-{15.73}]. The rocks are distinctly enriched in Rb, Sr and Ba ({46.3}-316 μg/g, 349-1220 μg/g and 386-2394 μg/g, respectively), high in U and Th ({1.17}-{8.10} μg/g and {2.58}-{27.0} μg/g, respectively), moderate in Zr and Hf ({87.5}-241 μg/g and {2.83}-{7.52} μg/g, respectively), and depleted in Nb and Ta ({4.81}-{16.8} μg/g and {0.332}-{1.04} μg/g, respectively). In the primitive mantle-normalized incompatible element spidergram, U, K, Sr and Hf show positive anomalies, whereas Th, Nb, Ta, P, and Ti show negative anomalies. The rocks are strongly depleted in Cr and Ni ({21.4}-1470 μg/g and {7.79}-562 μg/g, respectively), and their transition element distribution curves are obviously of type-W. The ({{}+{87}Sr/+{86}Sr)-i} ratios range from {0.704184} to {0.707539}; ({{}+{143}Nd}/{{}+{144}Nd)-i} from {0.512265} to {0.512564}; and ε-{Nd}(t) from {-6.3} to {-0.4}. These geochemical features might suggest that the potential source of the high-K igneous rocks in the Liuhe-Xiangduo area is similar to the EM2, which may be similar to the material enriched K that is located under the crust-mantle mixed layer. The mafic deep-derived enclaves in the high-K igneous rocks belong to chance xenoliths. Their ({{}+{87}Sr/+{86}Sr)-i} ratios range from {0.706314} to {0.707198}; ({{}+{143}Nd}/{{}+{144}Nd)-i} from {0.512947} to {0.513046}; and ε-{Nd}(t) from {+7.0} to {+9.0}. These geochemical features might indicate that the enclaves probably came from the depleted mantle. The P-T conditions of the enclaves also showed that the enclaves are middle-lower crust metamorphic rocks, which were accidentally captured at 20-50 km level by rapidly entrained high-K magma, whose source is over 50 km in depth.
文摘The kinetics of liquid-phase hydrogenation of toluene catalyzed by MlNi5 was studied by investigating the influences of the reaction temperature and pressure on the mass transfer-reaction processes inside the slurry. The results show that the reaction rate accelerates when the reaction temperature increases, and reaches its maximum at about 490 K, but if temperature is higher than 510 K, the reaction rate decreases rapidly. The whole reaction process is controlled by the reaction at the surface of the catalyst particles. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particle can be neglected. The apparent reaction rate is zero order for toluene concentration and first order for hydrogen concentration in the liquid phase. The kinetic model is obtained. The kinetic model fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of MlNi5-toluene slurry system is 41.01 kJ·mol-1.
