نتایج جستجو برای: ordinary chondrite
تعداد نتایج: 50446 فیلتر نتایج به سال:
Composite spectra of different rotational aspects of the S asteroid 433 Eros were assembled from previous studies, covering the wavelength range 0ø33-2.5 grn. These data allow us to measure significant attributes of Eros's spectrum• its mafic mineral absorptions, and the degree and nature of compositional heterogeneity of its surfaceo We also evaluated previous Sasteroid taxonomies using indepe...
High-resolution transmission electron microscopy, shows that carbon in the Allende carbonaceous chondrite meteorite is predominantly a poorly crystalline graphite. Such material is of interest as an important carrier of the isotopically anomalous noble gases found in carbonaceous chondrites.
Non-differentiated asteroids are among the most primitive objects in our Solar System, having escaped intense heating mechanisms. To help us understand information contained reflectance spectra measured on asteroids, we analyzed meteorites laboratory. We present an in-depth analysis of a large set spectra: 23 CV3, 15 CO3, 4 CR2 and 31 Unequilibrated Ordinary Chondrites (UOCs). Each samples has ...
From mid-Ordovician ∼470 Myr-old limestone >100 fossil L-chondritic meteorites have been recovered, representing the markedly enhanced flux of meteorites to Earth following the breakup of the L-chondrite parent body. Recently one anomalous meteorite, Österplana 065 (Öst 65), was found in the same beds that yield L chondrites. The cosmic-ray exposure age of Öst 65 shows that it may be a fragment...
The discovery of a natural quasicrystal, icosahedrite (Al63Cu24Fe13), accompanied by khatyrkite (CuAl2) and cupalite (CuAl) in the CV3 carbonaceous chondrite Khatyrka has posed a mystery as to what extraterrestrial processes led to the formation and preservation of these metal alloys. Here we present a range of evidence, including the discovery of high-pressure phases never observed before in a...
The concentrations and isotopic composition of He, Ne and Ar in 29 chondrites and 1 achondrite have been determined. Detailed accounts of the experimental technique used and the reproducibility and accuracy obtained are given. The U,Th-He4, and K-Ar ages derived from our results are in agreement with the already known age distributions of the different chondrite classes. Our measurements have r...
The Open University's repository of research publications and other research outputs Combined chemical-oxygen isotope study of large igneous inclusions in ordinary chondrites Conference Item (2016). Combined chemical-oxygen isotope study of large igneous inclusions in ordinary chondrites. For guidance on citations see FAQs. c [not recorded] Version: Version of Record Copyright and Moral Rights ...
Introduction: Buchanan et al. [1] and Zolensky et al. [2] described carbonaceous chondrite fragments in a variety of howardites and concluded that the majority are CM2 and CR2 materials. Gounelle et al. [3] also described similar, but very small, fragments in these meteorites. These clasts are important because they represent materials that were in orbital proximity to the HED parent body (4 Ve...
We review the Al ages of chondrules in various type 3.0 chondrites. The Al ages of chondrules are 1–3 Myr after calcium-aluminum-rich inclusion (CAI) for LL3.0, CO3.0, and Acfer 094 (Ungrouped C 3.0). Available data for chondrules in CR chondrites indicate that many chondrules are relatively younger (‡3 Myr), although data from chondrules in CR3.0 are not yet available to confirm their younger ...
the neogene intrusion masses in the noudeh-enghelab area located to the north of sabzevar ophiolite have cut the late cretaceous ophiolitic rocks, sedimentary- volcanic and eocene volcanic rocks and have been covered by pliocene and quaternary deposits. the margin is of lava with basalt, phyric andesite-basalt and andesite and the central parts (dome shaped) composed of phyric andesite-trachyan...
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