The Juancheng chondrite──A new meteorite falling recently in China

The Juancheng chondrite, a new meteorite falling recently in Juancheng County, Shandong Province, China, is classified as an H5 (S2) chondrite based on the compositions of olivine (Fa= 19.2, σ Fa=0.46) and low-Ca pyroxene (Fs=16.9, σ Fa=0.4). The plagioclase in the Juancheng chondrite is rich in CaO, indicating a relatively high metamorphic temperature the parent body underwent.     

Grove Mountains （GRV）99027： A new Martian meteorite

We report the petrography, mineral chemistry and oxygen isotopic composition of GRV 99027, a new Martian meteorite recently collected during the 16th Chinese Antarctic Research Expedition. This meteorite consists of two textural regions. The interstitial region is characterized by the presence of plagioclase and phosphate, and higher FeO contents of olivine and orthopyroxene, in comparison with the poikilitic region. All of the observations are similar to the three known Martian lherzolites. We classify GRV 99027 as the fourth sample of Martian lherzolite.     

奇特的小行星——灶神星

灶神星(Vesta)是小行星主带的最大成员之一。主带的最大成员--谷神星(Ceres)已归类为矮行星,灶神星也是候选的矮行星。不同于其他类型的小行星,灶神星是很奇特的。灶神星的光谱跟HED 陨石相似,因而推断它是该群陨石的母体。在灶神星族小行星和V 型小行星中,其他小行星都很小,可认为它们是灶神星受撞击而抛出的碎块。跟含水的谷神星不同,灶神星是缺水的火成岩石星,因此,它们倍受关注。为揭示谷神星和灶神星的奥秘,美国专门发射黎明号(Dawn)飞船去探测它们,现在已完成了环绕灶神星一年多的探测,正在飞往谷神星途中。黎明号飞船所摄的灶神星图像令人大为震惊,其南极区有两个大陨击盆地,证实了它曾受到巨大撞击所抛出碎块成为有关的小行星和陨石,并且造成其赤道区的大沟槽。灶神星有相似于类地行星的核、幔、壳结构和早期演化史,可能是遗留的原行星(protoplanet),因而,对灶神星的研究将有助于了解类地行星的起源和早期演化等问题。     

Xieite, a new mineral of high-pressure FeCr2O4 polymorph

Xieite, a new mineral, occurs in the shock vein of the Suizhou meteorite. The mineral has an orthorhombic structure and its space group is Bbmm. The cell parameters are a = 9.462（6） A, b = 9.562（9） A, c = 2.916（1）A. The crystal-chemical formula is （Fe0.87Mg0.13Mn0.01）1.01（Cr1.62AI0.25Ti0.08V0.02）1.97O4, or simply formula FeCr2O4. Stronger X-ray diffraction lines are [d （A）, I/Io]： （2.675, 100）, （2.389, 20）, （2.089, 10）, （1.953, 90）, （1.566, 60）, （1.439, 15）, （1.425, 15）, （1.337, 40）. Xieite is a high pressure polymorph of FeCr2O4 and formed by solid-state transformation of chromite under shock-induced high pressure and temperature, in association with other high-pressure minerals including ringwoodite, majorite, lingunite and tuite. The P-Tcondition for the formation of xieite is estimated to be 18--23 GPa and 1800--1950℃, respectively. Xieite has recently been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association （IMA 2007-056）. The mineral name, xieite, is named after Xiande Xie.     

Impact-derived features of the Xiuyan meteorite crater

Up to now, 176 meteorite impact craters have been found on the Earth. Among these craters, none of them lies in China. The Xiuyan crater is located in the Liaodong Peninsula of China. This bowl-shaped crater has a diameter of 1.8 km and depth of about 150 m. The impact-derived features include planar deformation features （PDFs） in quartz, shatter cones, impact breccia, and radial valleys on the wall of rim. It is the first confirmed meteorite impact crater in China.