High-pressure minerals and new lunar mineral changesite-(Y) in Chang’e-5 regolith  

作　　者：Jing Yang Wei Du 

机构地区：[1]Center for Lunar and Planetary Sciences,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China [2]State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences(CAS),Guiyang 550081,China [3]CAS Center for Excellence in Comparative Planetology,Hefei 230026,China

出　　处：《Matter and Radiation at Extremes》2024年第2期90-97,共8页极端条件下的物质与辐射（英文）

基　　金：supported by the B-Type Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB 41000000);the National Natural Science Foundation of China(Grant Nos.41773052,41973058,and 42003054);the Key Research Program of the Chinese Academy of Sciences(Grant No.ZDBS-SSWJSC007-10);the Pre-Research Project on Civil Aerospace Technologies funded by the CNSA(Grant No.D020201);the China Postdoctoral Science Foundation(Grant No.2020M680155).

摘　　要：Forty-five years after the Apollo and Luna missions, China’s Chang’e-5 (CE-5) mission collected ∼1.73 kg of new lunar materials from one ofthe youngest basalt units on the Moon. The CE-5 lunar samples provide opportunities to address some key scientific questions related to theMoon, including the discovery of high-pressure silica polymorphs (seifertite and stishovite) and a new lunar mineral, changesite-(Y). Seifertitewas found to be coexist with stishovite in a silica fragment from CE-5 lunar regolith. This is the first confirmed seifertite in returned lunarsamples. Seifertite has two space group symmetries (Pnc2 and Pbcn) and formed from an α-cristobalite-like phase during “cold” compressionduring a shock event. The aftershock heating process changes some seifertite to stishovite. Thus, this silica fragment records different stagesof an impact process, and the peak shock pressure is estimated to be ∼11 to 40 GPa, which is much lower than the pressure condition forcoexistence of seifertite and stishovite on the phase diagram. Changesite-(Y), with ideal formula (Ca_(8)Y)◻Fe^(2+)(PO_(4))_(7) (where ◻ denotes avacancy) is the first new lunar mineral to be discovered in CE-5 regolith samples. This newly identified phosphate mineral is in the form ofcolumnar crystals and was found in CE-5 basalt fragments. It contains high concentrations of Y and rare earth elements (REE), reaching upto ∼14 wt. % (Y,REE)2O3. The occurrence of changesite-(Y) marks the late-stage fractional crystallization processes of CE-5 basalts combinedwith silicate liquid immiscibility. These new findings demonstrate the significance of studies on high-pressure minerals in lunar materials andthe special nature of lunar magmatic evolution.

关 键 词：evolution MINERALS BASALT 

分 类 号：P59[天文地球—地球化学]