نتایج جستجو برای: meteorite
تعداد نتایج: 2201 فیلتر نتایج به سال:
The lunar meteorite Sayh al Uhaymir 169 consists of an impact melt breccia extremely enriched with potassium, rare earth elements, and phosphorus [thorium, 32.7 parts per million (ppm); uranium, 8.6 ppm; potassium oxide, 0.54 weight percent], and adherent regolith. The isotope systematics of the meteorite record four lunar impact events at 3909 +/- 13 million years ago (Ma), approximately 2800 ...
This review is intended principally to be a reasonably comprehensive bibliography. It covers papers by workers in stable isotope geochemistry in the United States that have been published or presented at national meetings since the last quadrennial report. The titles of the papers in the bibliography are in most cases indicative of the general content, so only the highlights are described below...
In this study, meteorite pieces, with total weight of 259 grams, have been studied which is not listed in the world bulletin of meteorites. In order to classify these samples, after preparing microscopic thin sections and performing accurate petrography, using geochemical data of the major elements and trace elements of whole rock, obtained from XRF and ICPMS methods in Zarazma company’s labora...
Current interest in nanomaterials is focused mostly on artificial materials fabricated for various applications. However, naturally occurring nanocrystal arrays, like those recently found in the meteorite that fell near Chelyabinsk in Russia on 15 February, 2013, can provide some new insights into the nature of nanomaterials, including the conditions for their natural occurrence. Here we report...
The diatoms discovered in the Polonnaruwa meteorite are interpreted as originating in comets and the dust in interstellar space. The exceptionally porous structure of the Polonnaruwa meteorite points to it being a recently denuded cometary fragment. Microorganisms that were present in a freeze-dried state within pores and cavities may have survived entry to be added to the terrestrial biosphere.
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