The 238U/235U Ratio as an Indicator of Redox Conditions in the Ediacaran Paleobasin (Sequence of the Chaya River, Baikal–Patom Highland, Southern Part of Central Siberia)


Дәйексөз келтіру

Толық мәтін

Ашық рұқсат Ашық рұқсат
Рұқсат жабық Рұқсат берілді
Рұқсат жабық Тек жазылушылар үшін

Аннотация

Abstract—This article is devoted to a study of variations in the U isotopic composition (238U/235U) in the section of clastic–carbonate Ediacaran sediments exposed along the Chaya River in the southern part of Central Siberia (Russia). Measurements of 238U/235U in the rocks were performed using a high-precision (±0.07, 2SD) MC-ICP-MS with a 233U–236U double isotope spike. The total variation range of δ238U in the studied carbonate rocks was −0.91 to −0.01‰. Extremely low values of δ238U (−0.91‰, −0.9‰, and −0.84‰), which were found in a number of samples from the lower part of the section, are interpreted as the result of postsedimentation processes affecting the rocks. In the overlying sediments, the range of δ238U variations is smaller from −0.49 to −0.01‰. Here, regular “weighting” of the U isotopic composition observed upwards through the section indicates an increase in the reduction conditions at this time (about 550 Ma) in the paleobasin. This conclusion is consistent with the elevated concentrations of U, Mo, and V in the Late Ediacaran sedimentary rocks of the region studied.

Авторлар туралы

A. Chugaev

Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy
of Sciences

Хат алмасуға жауапты Автор.
Email: vassachav@mail.ru
Ресей, Moscow, 119017

I. Chernyshev

Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy
of Sciences

Email: vassachav@mail.ru
Ресей, Moscow, 119017

B. Pokrovsky

Geological Institute, Russian Academy of Sciences

Email: vassachav@mail.ru
Ресей, Moscow, 119017

G. Mandzhieva

Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy
of Sciences

Email: vassachav@mail.ru
Ресей, Moscow, 119017

B. Gareev

Kazan (Volga Region) Federal University

Email: vassachav@mail.ru
Ресей, Kazan

A. Sadasyuk

Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy
of Sciences

Email: vassachav@mail.ru
Ресей, Moscow, 119017

G. Batalin

Kazan (Volga Region) Federal University

Email: vassachav@mail.ru
Ресей, Kazan

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