The stabilization of the world population and the achievement of sustained development depend not only on the endeavours of governments of nations,but also on further strengthening and promotion of international coope...The stabilization of the world population and the achievement of sustained development depend not only on the endeavours of governments of nations,but also on further strengthening and promotion of international cooperation,The developed countries should make eforts to improve the international economic environment,increase funds for population and development programmes and transfer technology at preferable conditions.展开更多
The Peng Co ophiolite is located to the west of Peng lake in the area of lakes in north Tibet, which belongs to the Baila-Yilashan sub-belt of the the middle Bangong Co-Nujiang ophiolitic belt. The Peng Co ophiolite i...The Peng Co ophiolite is located to the west of Peng lake in the area of lakes in north Tibet, which belongs to the Baila-Yilashan sub-belt of the the middle Bangong Co-Nujiang ophiolitic belt. The Peng Co ophiolite is mainly composed of mantle peridotites, cumulates, diabase dikes. About 70 percent peridotites are harzburgites and 30 percent are lherzolites. Mineral chemistry of the Peng Co lherzolitesare characterized by low Fo contents(88.85–90.33) of olivine and high Al2O3 content(4.26%–7.25%) in pyroxenes. Compared to the primitive mantle, the Peng Co peridotites have relatively higher MgO contents, lower CaO, Al2O3 and TiO2 contents. The total rare-earth element(REE) contents of the lherzolites are 1.11–1.53 ppm, which are lower than those of the primitive mantle. The chondritenormalized REE patterns of the Peng Co peridotites display slight loss in LREE. In the primitive mantle-normalized spider diagram, the Peng Co peridotites exhibit negative Rb and Zr anomalies and intensively positive U, Ta, Sr anomalies. The PGE contents of Peng Co lherzolites are between 22.9–27 ppb. The chondrite-normalized PGE patterns of the Peng Co lherzolites are consistent with that of the primitive mantle. Mineral and whole-rock geochemistry characteristics of the Peng Co lherzolites show an affinity to abyssal peridotites, indicating that it may have formed in the mid-ocean ridge setting. Through quantitative modeling, we conclude that the Peng Co lherzolites formed after 5%–10% degree of partial melting of the spinelphase lherzolite mantle source. The sharp increase of Cr#(56.74–60.84)in Spinel of harzburgites and relatively high Pd/Ir and Rh/Ir ratios suggest that they have experienced melt-rock reaction. The crystallization sequence of Peng Co cumulate is olivine-clinopyroxene-plagioclase. The Mg# value of clinopyroxene in cumulate peridotite ranges from 86.92 to 89.93, and the mean value of Fo is 84.45, which is obviously higher than that of MOR-type ophiolite cumulates. The mineral composition, sequence of magmatic crystallization and mineral components of Peng Co cumulate are similar to those of the cumulate formed by the SSZ-type ophiolite in the subduction zone. Therefore, we can draw a preliminary conclusion that Peng Co lherzolites were formed in an environment of mid oceanic ridge and were remnants of the spinel lherzolite zone which experienced a partial melting of no more than 10%. In the later period, due to the intra-oceanic subduction, it experienced the rock-meltinteraction, and thus formed the SSZ-type cumulate and harzburgite of high Cr value.展开更多
■Since April,all Magazine has examined five artist couples working in China.This month we lookatthe youngest of the artistic duos,Peng Yu and Sun Yuan,whose
The following is the synopsis of the speech made by Minister Peng Peiyun of the State Family Planning Commission at the Sixth National Symposium on Pop-ulation Science and concurrently the Conference of the Population...The following is the synopsis of the speech made by Minister Peng Peiyun of the State Family Planning Commission at the Sixth National Symposium on Pop-ulation Science and concurrently the Conference of the Population Association of China.She talked at length about the main experiences in the implementation of the family planning programme and the latest popula-tion trends in China.--Editor.展开更多
The following is the synopsis of the two reports made by Mme.Peng Peiyun,State Councillor and Minister of the State Family Planning Commission(SFPC),at the Na-tional Family Planning Confcrence convened by SFPC from Ma...The following is the synopsis of the two reports made by Mme.Peng Peiyun,State Councillor and Minister of the State Family Planning Commission(SFPC),at the Na-tional Family Planning Confcrence convened by SFPC from March 19 to 21,1994 and the National Forum on Family Planning Work jointly sponsored by the Central Committee of the Communist Party of China and the State Couocil on March 22.---editor.展开更多
文摘The stabilization of the world population and the achievement of sustained development depend not only on the endeavours of governments of nations,but also on further strengthening and promotion of international cooperation,The developed countries should make eforts to improve the international economic environment,increase funds for population and development programmes and transfer technology at preferable conditions.
基金granted by National Natural Science Foundation of China(41720104009)China Geology Survey Project(DD20160023-01)Foundation of MLR(201511022)
文摘The Peng Co ophiolite is located to the west of Peng lake in the area of lakes in north Tibet, which belongs to the Baila-Yilashan sub-belt of the the middle Bangong Co-Nujiang ophiolitic belt. The Peng Co ophiolite is mainly composed of mantle peridotites, cumulates, diabase dikes. About 70 percent peridotites are harzburgites and 30 percent are lherzolites. Mineral chemistry of the Peng Co lherzolitesare characterized by low Fo contents(88.85–90.33) of olivine and high Al2O3 content(4.26%–7.25%) in pyroxenes. Compared to the primitive mantle, the Peng Co peridotites have relatively higher MgO contents, lower CaO, Al2O3 and TiO2 contents. The total rare-earth element(REE) contents of the lherzolites are 1.11–1.53 ppm, which are lower than those of the primitive mantle. The chondritenormalized REE patterns of the Peng Co peridotites display slight loss in LREE. In the primitive mantle-normalized spider diagram, the Peng Co peridotites exhibit negative Rb and Zr anomalies and intensively positive U, Ta, Sr anomalies. The PGE contents of Peng Co lherzolites are between 22.9–27 ppb. The chondrite-normalized PGE patterns of the Peng Co lherzolites are consistent with that of the primitive mantle. Mineral and whole-rock geochemistry characteristics of the Peng Co lherzolites show an affinity to abyssal peridotites, indicating that it may have formed in the mid-ocean ridge setting. Through quantitative modeling, we conclude that the Peng Co lherzolites formed after 5%–10% degree of partial melting of the spinelphase lherzolite mantle source. The sharp increase of Cr#(56.74–60.84)in Spinel of harzburgites and relatively high Pd/Ir and Rh/Ir ratios suggest that they have experienced melt-rock reaction. The crystallization sequence of Peng Co cumulate is olivine-clinopyroxene-plagioclase. The Mg# value of clinopyroxene in cumulate peridotite ranges from 86.92 to 89.93, and the mean value of Fo is 84.45, which is obviously higher than that of MOR-type ophiolite cumulates. The mineral composition, sequence of magmatic crystallization and mineral components of Peng Co cumulate are similar to those of the cumulate formed by the SSZ-type ophiolite in the subduction zone. Therefore, we can draw a preliminary conclusion that Peng Co lherzolites were formed in an environment of mid oceanic ridge and were remnants of the spinel lherzolite zone which experienced a partial melting of no more than 10%. In the later period, due to the intra-oceanic subduction, it experienced the rock-meltinteraction, and thus formed the SSZ-type cumulate and harzburgite of high Cr value.
文摘■Since April,all Magazine has examined five artist couples working in China.This month we lookatthe youngest of the artistic duos,Peng Yu and Sun Yuan,whose
文摘The following is the synopsis of the speech made by Minister Peng Peiyun of the State Family Planning Commission at the Sixth National Symposium on Pop-ulation Science and concurrently the Conference of the Population Association of China.She talked at length about the main experiences in the implementation of the family planning programme and the latest popula-tion trends in China.--Editor.
文摘The following is the synopsis of the two reports made by Mme.Peng Peiyun,State Councillor and Minister of the State Family Planning Commission(SFPC),at the Na-tional Family Planning Confcrence convened by SFPC from March 19 to 21,1994 and the National Forum on Family Planning Work jointly sponsored by the Central Committee of the Communist Party of China and the State Couocil on March 22.---editor.
