Dpto Geología, Museo Nacional de Ciencias Naturales (MNCN-CSIC), C/José Gutierrez Abascal 2, Madrid 28006, Spain.
Talanta. 2013 Sep 30;114:152-9. doi: 10.1016/j.talanta.2013.03.070. Epub 2013 Apr 6.
The historical Madrid meteorite chondrite fell in 1896 showing thin melt veins with a 65% of brecciated forsterite fragments surrounded by a fine grained matrix formed by troilite, chromite and Fe-Ni blebs. It exhibits a delicate iron infill, neo-formation of troilite in pockets and shock veins and neo-formation of Na-feldspar formed at high temperature and fast quenching. The semi-quantitative mineral determinations were performed with IMAGEJ freeware and chemical mappings resulting in the following approximated compositions: olivine (55%); augite (10%); enstatite (10%); plagioclase (10%); chromite (2%); troilite (4%), kamacite-taenite α-γ-(Fe, Ni) (7%) and merrillite (7%). The specimen was also studied by computer tomography, micro-Raman spectroscopy and spectral cathodoluminescence. X-ray diffraction patterns were also recorded in non-destructive way on a polished surface because of the small size of the specimen. This combination of non-destructive techniques provides an improved knowledge on the Madrid-1896 meteorite compared to the previous study performed on the same specimen carried out twenty years ago by electron probe microanalysis and optical microscopy in destructive way. Limits of these techniques are the specimen's size in the analytical chambers and the threshold resolution of the microscopes analyzing shock veins micro-crystals.
马德里陨石 1896 年坠落,呈细熔脉状,角砾镁橄榄石碎片占 65%,周围为细粒基质,由陨硫铁、铬铁矿和 Fe-Ni 结核组成。它显示出精致的铁填充,在口袋和冲击脉中形成新的陨硫铁,以及在高温和快速淬火下形成的钠长石新形成。使用 IMAGEJ 免费软件进行半定量矿物测定,并进行化学绘图,得出以下近似成分:橄榄石(55%);辉石(10%);顽火辉石(10%);斜长石(10%);铬铁矿(2%);陨硫铁(4%),kamacite-taenite α-γ-(Fe,Ni)(7%)和 Merrillite(7%)。该标本还通过计算机断层扫描、微拉曼光谱和光谱阴极发光进行了研究。由于标本尺寸较小,还以非破坏性方式在抛光表面上记录了 X 射线衍射图谱。与二十年前对同一标本进行的破坏性电子探针微分析和光学显微镜研究相比,这些非破坏性技术的组合提供了对马德里 1896 陨石的更深入了解。这些技术的局限性在于分析腔体内的标本尺寸和分析冲击脉微晶的显微镜的分辨率阈值。