Highly fractionated chromium isotopes in Mesoproterozoic-aged shales and atmospheric oxygen
نویسندگان
چکیده
منابع مشابه
Oxygen Isotopes in Meteorites
Oxygen isotope abundance variations in meteorites are very useful in elucidating chemical and physical processes that occurred during the formation of the solar system (Clayton, 1993). On Earth, the mean abundances of the three stable isotopes are O: 99.76%, O: 0.039%, and O: 0.202%. It is conventional to express variations in abundances of the isotopes in terms of isotopic ratios, relative to ...
متن کاملLarge-scale fluctuations in Precambrian atmospheric and oceanic oxygen levels from the record of U in shales
The atmosphere–ocean system experienced a progressive change from anoxic to more oxidizing conditions through time. This oxidation is traditionally envisaged to have occurred as two stepwise increases in atmospheric oxygen at the beginning and end of the Proterozoic Eon. Here, we present a study of the redox-sensitive element, uranium, in organic-rich shales to track the history of Earth's enri...
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We have examined the distribution of individual Pu isotopes (239Pu, 240Pu, and 241Pu) in seawater from the Gulf of Maine (GOM). Samples were size-fractionated with a 1 kD cross-flow ultrafiltration (CFF) membrane. Subfractioned samples were radiochemically purified and Pu isotopes were analyzed using a three-stage thermal ionization mass spectrometer (TIMS). To our knowledge, this is the first ...
متن کاملOxygen Isotopes in Chondritic Interplanetary
Introduction: Planetary objects have preserved various amounts of oxygen derived from isotopically distinct reservoirs reflecting their origins and diverse physico-chemical histories [1]. An O-rich component is preserved in high temperature phases, such as refractory inclusions (CAIs) and some chondrules, whereas meteorite matrices are enriched in a relatively O-poor component [2]. The origin o...
متن کاملMain features of mudslides in tectonised highly fissured clay shales
Mudslides are widespread in the world, especially in areas occupied by highly-fissured plastic stiff clays. Despite their strong impact on structures, infrastructures and, in general, human activity, the knowledge concerning the causes and mechanisms of mudslides is still rather limited. The paper reports some results of long-term research on mudslides in tectonised highlyfissured plastic clay ...
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ژورنال
عنوان ژورنال: Nature Communications
سال: 2018
ISSN: 2041-1723
DOI: 10.1038/s41467-018-05263-9