3
Geologists have proven the effectiveness of a simple and cheap method for determining the age of minerals

Geologists have proven the effectiveness of a simple and cheap method for determining the age of minerals

Geologists have proven the effectiveness of a new method for determining the age of pyrites — minerals that appear during the formation of ore, during tectonic and sedimentary processes. The new method is simpler and more accurate than the classical one, besides it does not require a large number of samples for analysis.

To understand when geological processes occurred — the formation of ore, the movement of tectonic plates, and others — scientists use geochronology methods, for example, using minerals. In the course of geological processes, the mineral pyrite — iron disulfide is often formed. If you find out the age of pyrite, you can understand when the geological event occurred. Usually, the age of sulfides is determined by the rhenium-osmium method (Re-Os) — knowing their half-life and the number of isotopes in the mineral composition, the age of the sample is calculated. However, the measurement procedure is quite complicated, and the result is not accurate. In addition, about 400 mg of material is needed for analysis, and it is not always possible to get them. A possible alternative to this method is to determine the age by isotopes of uranium, thorium and helium (U-Th-He).

“In the last decade, a lot of research has been focused on the behavior of radiogenic helium in various minerals, which has not usually been studied in geochronology. Pyrite dating based on U-Th-He has several potential advantages over the traditional Re-Os dating technique. Firstly, it requires less material (~1 mg). Secondly, the methodology of U-Th-He dating is simpler, and its implementation is financially less costly,” Doctor of Geological and Mineralogical Sciences Ilya Vikentiev, Professor of the Department of Subsoil Use and Oil and Gas Affairs of the RUDN.

Scientists of the RUDN, St. Petersburg State University, the Institute of Geology and Geochronology of the Precambrian, the Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry of the Russian Academy of Sciences and the Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences measured the age of pyrite in the largest gold deposit in the Polar Urals — New Year’s-Monto using the U-Th-He method. Its reserves are estimated at 33 tons.

The researchers studied 70 pyrite particles with a size of 0.2-0.5 mm and a total mass of 1-2 mg. The samples were divided into six parts and the age was determined for each of them by the U-Th-He dating method. On average, it turned out to be 382 million years old. This coincided with another independent assessment, which was carried out on ore-bearing geothermal activity (it gave a result of about 380 million years).

“This is the second example of a successful application of the U-Th-He isotope system for pyrite dating and the first successful application for pyrite from modified rocks, so our work provides the next important step in the development of the U-Th-He dating technique. However, there are still many issues that need to be resolved in order to make this technique widely applicable and reliable. In the future, the U-Th-He system for pyrite will potentially become a useful tool for the geochronology of numerous geological processes accompanying the crystallization of sulfides,” Doctor of Geological and Mineralogical Sciences Ilya Vikentiev, Professor of the Department of Subsoil Use and Oil and Gas Affairs of the RUDN.

The results are published in the journal Geosciences.

Visiting Professors View all
12 Dec 2024
In 2024, RUDN started accepting applications for the new annual Prize for Scientific Achievement in Chemistry. The award was established to honour contributions to fundamental and applied research, as well as merit in achieving the UN Sustainable Development Goals.
1213
Scientific Conferences View all
12 Dec 2024
About 200 participants from Russia and 20 countries met at the National Interdisciplinary Scientific Seminar with International Participation “Law in Medicine. Medicine in Law: Points of Contact”. The subject was “Happy Motherhood: unsolved problems of obstetrics, gynaecology and perinatology”.
898
Similar newsletter View all
21 Apr
Building a sustainable future: what are SDGs and how RUDN helps achieve them

Imagine a world where everyone has enough food, clean water, access to education, and decent work. A world where nature is protected and the future of our planet is cared for. These are the Sustainable Development Goals—to achieve a sustainable future for all! To this end, in 2015, the United Nations (UN) defined 17 Sustainable Development Goals (SDGs). The SDGs are a global plan that helps countries and people work together towards a better future. All 193 UN member states have joined the plan.

58
21 Apr
Unfounded generalizations and false conclusions: RUDN scientists have identified AI “hallucinations” in the diagnosis of mental disorders

Researchers from the Faculty of Artificial Intelligence at RUDN University conducted a large-scale study that revealed systemic errors in large language models (LLMs) when diagnosing depression based on text. This work, carried out in collaboration with colleagues from AIRI, Federal Research Center “Computer Science and Control” of the Russian Academy of Sciences, Ivannikov Institute for System Programming of the Russian Academy of Sciences, Moscow Institute of Physics and Technology, and MBZUAI, not only identifies the problem but also lays the foundation for the creation of more reliable and secure tools for detecting depression and anxiety.

50
21 Apr
Rats and neurodegenerative processes: a junior researcher at RUDN University wins Academician A. P. Avtsyn Award

Alexandra Sentyabreva, a junior researcher at the Laboratory of Cell Technologies and Tissue Engineering at RUDN Research Institute of Molecular and Cellular Medicine at the Russian University of People's Friendship, won the competition for young scientists at the All-Russian Scientific Conference “Topical Issues of Morphogenesis in Norm and Pathology.” She was awarded the Academician A.P. Avtsyn Prize.

46
Similar newsletter View all