FOSSIL ORGANISMS IN METEORITES
نویسندگان
چکیده
منابع مشابه
Some Peculiarities of Isotopic Ratios of Noble Gases in Fossil Meteorites
Introduction: More than 80 fossil meteorites have been found in the ~4 m quarry layer of midOrdovician marine limestone in southern Sweden (Thorsberg quarry) [1, 2]. The analysis of noble gas data [2] in chromite grains from these meteorites has revealed a clear negative correlation between He, Ne concentrations and mass of the samples [3]. Similar correlation has been found also for cosmicray ...
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Our understanding of planet formation depends in fundamental ways on what we learn by analyzing the composition, mineralogy, and petrology of meteorites. Yet, it is difficult to deduce the compositional and thermal gradients that existed in the solar nebula from the meteoritic record because, in most cases, we do not know where meteorites with different chemical and isotopic signatures originat...
متن کاملFossil Meteorites of Sweden: What Are Their Cosmic-ray Exposure Ages?
Introduction: More than 80 L-chondritic fossil meteorites were found in Middle Ordovician limestone in the Thorsberg quarry at Kinnekulle in southern Sweden [1, 2]. All meteorite-bearing sediment beds at Thorsberg contain sediment-dispersed extraterrestrial chromite (SEC) grains of L chondrite composition [3]. Similar SEC grains were also found in several correlated sediment beds of other quarr...
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Although carbonate-precipitating cyanobacteria are ubiquitous in aquatic ecosystems today, the criteria used to identify them in the geological record are subjective and rarely testable. Differences in the mode of biomineralization between cyanobacteria and eukaryotes, i.e., biologically induced calcification (BIM) vs. biologically controlled calcification (BCM), result in different crystallogr...
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Primitive meteorites, interplanetary dust particles, and comets contain dust grains that formed around stars that lived their lives before the solar system formed. These remarkable objects have been intensively studied since their discovery a little over twenty years ago and they provide samples of other stars that can be studied in the laboratory in exquisite detail with modern analytical tool...
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ژورنال
عنوان ژورنال: Science
سال: 1881
ISSN: 0036-8075,1095-9203
DOI: 10.1126/science.os-2.51.275