“悬米”释义

碑刻铭文中多见"悬米"一词,或释为"悬水",即"瀑布",这是错误的。"悬米"之"米",实为""的俗写省讹,"悬渊",即"玄渊",碑铭中也多写作"玄源"。

Preparation and characterization of Martian soil simulant NEU Mars-1

To develop Martian soil simulant,basalts of the Chahar volcanic group in Wulanchabu,Inner Mongolia,China were selected as the simulant initial materials,which were ground and sorted to a predetermined particle size ratio,and small amounts of magnetite and hematite were added.The main phases of NEU Mars-1 simulant were plagioclase,augite and olivine.The glass transition and crystallization temperatures of NEU Mars-1 were 547.8 and 795.7°C,respectively.The complex dielectric constant,magnetic conductivity(0.99-1.045),and dielectric loss tangent angles(0.0025-0.030)of NEU Mars-1 were all stable in the frequency range of 2-18 GHz.Mossbauer spectroscopy results showed that the mass ratio of Fe2+to Fe3+in the simulant was 77.6:22.4.The NEU Mars-1 Martian soil simulant demonstrated particle size ratio,chemical composition,phase composition,thermal stability,and dielectric property similar to Martian soil,and can be used as the substitute material to extract oxygen and metals with in-situ resource utilization technologies.

Magma source and evolution law in Yueshan ore field, Anhui Province, China

Major elements, trace elements and sulfur, oxygen isotopic compositions of the main intrusions were studied in Yueshan area. The fact that intrusions enriched in Th and Sr, and depleted in Rb and Ba in this area, suggests that the original magma roots in alkali basalt magma of upper mantle, with deep characteristics. It can be seen that the diagenesis environments are the island arc and active continental margin areas from the lg τ to lg σ diagram of intrusions. With the increase of SiO2, Fe2O3, MnO and P2O5 decrease, which shows that the magma of Yueshan area endured crystal fractionation of ferromanganese mineral and apatite in early evolution stage. With the further rise and evolution of magma, magma composition of calcium increased, meanwhile enriched in Zr, and depleted in Nb and Ta. This indicates that crustal component is gradually added, the assimilation and contamination occur between magma and crustal material, which includes the magma evolving, from calc-alkaline series to alkaline series. The results show that crystal fractionation, assimilation and contamination are the main evolution law of magma in this area.

The water content and hydrogen isotope composition of continental lithospheric mantle and mantle-derived mafic igneous rocks in eastern China

The water contents of minerals and whole-rock in mantle-derived xenoliths from eastern China exhibit large variations and are generally lower than those from other on- and off-craton lithotectonic units. Nevertheless, the water contents of mineral and whole-rock in Junan peridotite xenoliths, which sourced from the juvenile lithospheric mantle, are generally higher than those elsewhere in eastern China. This suggests that the initial water content of juvenile lithospheric mantle is not low. There is no obvious correlation between the water contents and Mg~# values of minerals in the mantle xenoliths and no occurrence of diffusion profile in pyroxene, suggesting no relationship between the low water content of mantle xenolith and the diffusion loss of water during xenolith ascent with host basaltic magmas. If the subcontinental lithospheric mantle（SCLM） base is heated by the asthenospheric mantle, the diffusion loss of water is expected to occur. On the other hand, extraction of basaltic melts from the SCLM is a more efficient mechanism to reduce the water content of xenoliths. The primary melts of Mesozoic and Cenozoic basalts in eastern China have water contents, as calculated from the water contents of phenocrysts, higher than those of normal mid-ocean ridge basalts（MORB）. The Mesozoic basalts exhibit similar water contents to those of island arc basalts, whereas the Cenozoic basalts exhibit comparable water contents to oceanic island basalts and backarc basin basalts with some of them resembling island arc basalts. These observations suggest the water enrichment in the mantle source of continental basalts due to metasomatism by aqueous fluids and hydrous melts derived from dehydration and melting of deeply subducted crust. Mantle-derived megacrysts, minerals in xenoliths and phenocrysts in basalts from eastern China also exhibit largely variable hydrogen isotope compositions, indicating a large isotopic heterogeneity for the Cenozoic SCLM in eastern China. The water content that is higher than that of depleted MORB mantle and the hydrogen isotope composition that is deviated from that of depleted MORB mantle suggest that the Cenozoic continental lithospheric mantle suffered the metasomatism by hydrous melts derived from partial melting of the subducted Pacific slab below eastern China continent. The metasomatism would lead to the increase of water content in the SCLM base and then to the decrease of its viscosity. As a consequence, the SCLM base would be weakened and thus susceptible to tectonic erosion and delamination. As such, the crust-mantle interaction in oceanic subduction channel is the major cause for thinning of the craton lithosphere in North China.