Results 191 to 200 of about 6,913 (220)
Some of the next articles are maybe not open access.
Meteoritics & Planetary Science, 2001
Abstract— Isotopic compositions and abundances of boron were measured in sixteen chondrules from seven chondrites by ion microprobe mass spectrometry. The chondrules are of the porphyritic, barred, and radial type and host meteorites include carbonaceous, ordinary, and enstatite chondrites.
Hoppe, P. +3 more
openaire +2 more sources
Abstract— Isotopic compositions and abundances of boron were measured in sixteen chondrules from seven chondrites by ion microprobe mass spectrometry. The chondrules are of the porphyritic, barred, and radial type and host meteorites include carbonaceous, ordinary, and enstatite chondrites.
Hoppe, P. +3 more
openaire +2 more sources
Annual Review of Earth and Planetary Sciences, 1997
▪ Abstract Chondrules are ∼1-mm igneous droplets in primitive meteorites, and their abundance suggests widespread melting in the protoplanetary disk. Chondrules with relict unmelted grains or igneous rims record multi111ple melting events. There are two main types of chondrules, type I (FeO-poor and volatile-poor) and type II [FeO-rich and ...
openaire +1 more source
▪ Abstract Chondrules are ∼1-mm igneous droplets in primitive meteorites, and their abundance suggests widespread melting in the protoplanetary disk. Chondrules with relict unmelted grains or igneous rims record multi111ple melting events. There are two main types of chondrules, type I (FeO-poor and volatile-poor) and type II [FeO-rich and ...
openaire +1 more source
Meteoritics, 1970
Very small chondrules, which are less than 250μ in size and are referred to as microchondrules, were discovered in twelve chondritic meteorites. The morphology, composition, and structure of these microchondritic bodies are investigated. In particular, the description of the principal, minor, and accessory minerals is given in some detail ...
openaire +1 more source
Very small chondrules, which are less than 250μ in size and are referred to as microchondrules, were discovered in twelve chondritic meteorites. The morphology, composition, and structure of these microchondritic bodies are investigated. In particular, the description of the principal, minor, and accessory minerals is given in some detail ...
openaire +1 more source
The dependence of chondrule density on chondrule size
Earth and Planetary Science Letters, 1980Spherical chondrules disaggregated from the meteorite Bjurbole have been found to have densities which vary as a function of size. The relationship is: ϱ = (3.78±0.06) − (1.25±0.37) d where ϱ is the chondrule density in g cm −3 and d is the diameter in cm.
openaire +1 more source
The frequency of compound chondrules and implications for chondrule formation
Meteoritics & Planetary Science, 2004Abstract— The properties of compound chondrules and the implications that they have for the conditions and environment in which chondrules formed are investigated. Formulae to calculate the probability of detecting compound chondrules in thin sections are derived and applied to previous studies.
Fred J. Ciesla +2 more
openaire +1 more source
Meteoritics & Planetary Science, 2002
Abstract— We measured the sizes and textural types of 719 intact chondrules and 1322 chondrule fragments in thin sections of Semarkona (LL3.0), Bishunpur (LL3.1), Krymka (LL3.1), Piancaldoli (LL3.4) and Lewis Cliff 88175 (LL3.8). The mean apparent diameter of chondrules in these LL3 chondrites is 0.80 φ units or 570 μm, much smaller than the previous ...
Victoria E. Nelson, Alan E. Rubin
openaire +1 more source
Abstract— We measured the sizes and textural types of 719 intact chondrules and 1322 chondrule fragments in thin sections of Semarkona (LL3.0), Bishunpur (LL3.1), Krymka (LL3.1), Piancaldoli (LL3.4) and Lewis Cliff 88175 (LL3.8). The mean apparent diameter of chondrules in these LL3 chondrites is 0.80 φ units or 570 μm, much smaller than the previous ...
Victoria E. Nelson, Alan E. Rubin
openaire +1 more source
Relict and other anomalous grains in chondrules: Implications for chondrule formation
Journal of Geophysical Research: Solid Earth, 1984We have identified relict olivine and pyroxene grains in chondrules from ordinary and carbonaceous chondrites that probably did not crystallize in situ. Some of these olivines are clear, but others contain fine‐grained Fe,Ni (‘dusty olivines’) and resemble previously described occurrences in ordinary chondrites.
Alfred Kracher +2 more
openaire +1 more source
Geochemistry, 2007
Abstract The recently discovered metal-rich carbonaceous chondrite Isheyevo consists of Fe, Ni-metal grains, chondrules, heavily hydrated matrix lumps and rare refractory inclusions. It contains several lithologies with mineralogical characteristics intermediate between the CH and CB carbonaceous chondrites; the contacts between the lithologies are ...
Alexander N. Krot +2 more
openaire +1 more source
Abstract The recently discovered metal-rich carbonaceous chondrite Isheyevo consists of Fe, Ni-metal grains, chondrules, heavily hydrated matrix lumps and rare refractory inclusions. It contains several lithologies with mineralogical characteristics intermediate between the CH and CB carbonaceous chondrites; the contacts between the lithologies are ...
Alexander N. Krot +2 more
openaire +1 more source
Chondrules: Suggestion Concerning the Origin
Science, 1966The millimeter-sized, sometimes glassy spheroids called chondrules that occur abundantly in stony meteorites may have been produced by lightning in the primitive Laplacian-type nebula while earthy materials were condensing and collecting to form the asteroids and the terrestrial planets.
openaire +2 more sources
Chondrules in Antarctic micrometeorites
Meteoritics & Planetary Science, 2005Previous studies of unmelted micrometeorites (>50 μm) recovered from Antarctic ice have concluded that chondrules, which are a major component of chondritic meteorites, are extremely rare among micrometeorites. We report the discovery of eight micrometeorites containing chondritic igneous objects, which strongly suggests that at least a portion of ...
M. J. Genge, A. Gileski, M. M. Grady
openaire +1 more source