Funding source: National Science Centre Poland OPUS-29
Project ID: 2025/57/B/ST10/01022
Project title: Stable potassium isotope fractionation by phyllosilicates
Acronym: SKIP (Stable K Isotopes in Phyllosilicates)
Project’s summary
Continental silicate weathering has been proposed to be one of the most important processes involved in the atmospheric CO2 drawdown. Alkali and alkaline Earth metal cations liberated from silicates during weathering are transported to the ocean, where Ca2+ reacts with CO2-derived HCO3-, leading to the formation of carbonates and reduction of the atmospheric CO2 levels. Since weathering is the most intense during warm periods, it provides negative feedback to global warming. A critical process that counterbalances silicate weathering is the formation of marine authigenic phyllosilicates, i.e., so-called “reverse weathering”. During reverse weathering, cations are incorporated into the clay minerals' structure, which leads to the release of CO2 from the ocean. Tracing the intensity of both continental and reversed weathering throughout Earth’s history is crucial in understanding past and current climate changes.
In recent years, a new proxy of the intensity of weathering has been proposed – the 41K/39K isotope ratio (reported as δ41K). Potassium is a major cation in seawater with a strong link to the silicate weathering and reverse weathering. Potassium is enriched in primary silicates, such as K-feldspars, and micas, and with marine authigenic phyllosilicates such as glauconite and illite. The main source of K to the ocean is riverine input, with the average δ41K of -0.38 ± 0.04‰. It is therefore puzzling why the δ41K value of seawater is +0.12‰, especially since the other K source to the ocean, hydrothermal vents, also have δ41K lower than +0.12‰. This discrepancy is tentatively explained by the preferential uptake of 39K by authigenic marine phyllosilicates. However, the exact fractionation factors are not known. There are also unanswered questions regarding the terrestrial part of the K cycle. The heavy K isotope seems to be preferentially lost during weathering, leading to low δ41K values of the weathering residue. Laboratory experiments provide contradictory results – initial enrichment of leachate in 39K due to kinetic effects is followed by virtually no fractionation at more advanced stages of K
leaching.
The aim of the project is to address the existing gaps in knowledge on the K isotope systematics. Potassium adsorption and leaching experiments will be performed on monomineralic samples, which will allow for a better understanding of mechanisms governing K fractionation. The focus will be on K interactions with expandable clay minerals, i.e., minerals that provide the largest percent of mineral surfaces capable of interactions with K+ in nature. In particular, the influence of various crystallochemical properties of clay minerals on the K isotope fractionation during adsorption and desorption will be explored. The laboratory experiments will be supplemented with a detailed investigation of natural samples coming from soils, weathering profiles, and marine sediments involving δ41K measurement coupled with the state-of-the-art quantitative analysis of the samples’ phase composition, allowing for distinction between authigenic and detrital K pools. Experiments will be supplemented by the ab initio simulations of various K-bearing clay mineral structures, aiming at the determination of K isotope fractionation factors. The project goals will be to answer the following questions: How does the clay mineral structure and crystallochemical composition affect the K isotope fractionation during adsorption? What are the K isotope fractionation effects during K release from primary phyllosilicates? What are the K isotope fractionation effects during reverse weathering? What are the systematics of K isotopes in weathering products? What insights into K isotope fractionation can be gained with ab initio calculations?
The above-mentioned goals will be achieved by the application of a series of analytical techniques to the investigated samples. Potassium content and isotope composition will be measured. In addition, certain crystallochemical features will be characterized with the Fourier Transform Infrared Spectroscopy. X-ray diffraction, cation exchange capacity, and chemical analysis. The completion of the project will allow for a better understanding of the K isotope fractionation effects associated with the Earth’s K cycle. This, in turn, will facilitate the use of δ41K as a tracer of the silicate weathering intensity and associated atmospheric CO2 level fluctuation throughout the Earth’s history
Principal Investigator: Dr.Artur Kuligiewicz; email: ndkuligi@cyf-kr.edu.pl
Application deadline: 10.01.2026
Call results: 31.01.2026
Start of the scholarship: 01.03.2026
Duration of the employment: 48 miesięcy
Remuneration: 5000 PLN for the first 24 months; 6500 PLN for the next 24 months (in the case of a positive mid-term evaluation)
Location: Institute of the Geological Sciences, Polish Academy of Sciences, Research Centre in Kraków
We offer:
• Employment at a leading geological research institute in Poland and cooperation with an international research team;
• A research scholarship of 5,000 PLN for the first 24 months of employment and 6,500 PLN for the subsequent 24 months (subject to a positive mid-term evaluation);
• The opportunity to gain experience in the field of non-traditional light isotopes, as well as in laboratory procedures and the analytical techniques available in the ClayLab Group;
• The opportunity to participate in international scientific conferences and to undertake a research visit at foreign partner institutions.
The Institute of Geological Sciences does not participate in the costs of relocation to Poland or Krakow.
Requirements / Expectations:
• A Master’s degree in geology, materials engineering, or chemical sciences;
• Ability to work both independently and as part of a team;
• Strong interest in clay mineralogy;
• Experience in laboratory work;
• Ability for critical thinking and independent data analysis;
• Good work organization skills;
• Fluency in spoken and written English;
• Experience working with clay minerals, basic knowledge of X-ray diffraction (XRD) and infrared spectroscopy (FTIR), and familiarity with the R programming environment will be an advantage but are not required
Duties / Responsibilities:
The scholarship holder will be involved in the project entitled “Stable potassium isotope fractionation by phyllosilicates.” As part of the project, the duties of the scholarship holder will include:
• Conducting potassium adsorption and desorption experiments on clay mineral structures;
• Participation in fieldwork;
• Characterization of the obtained materials and samples collected during fieldwork;
• Analysis and interpretation of the data obtained within the project;
• Participation in the preparation of scientific publications;
• Preparation of conference abstracts, participation in international conferences, and preparation of periodic reports;
• Presentation of results at international conferences (oral presentations and posters);
• Participation in the Doctoral School organized at the Institute of Geological Sciences PAS (geoplanetschool.pl).
Applications’ evaluation criteria:
The evaluation criteria are described in the following document: Regulations On Awarding Scholarships In NCN-Funded Research Project (https://www.ncn.gov.pl/sites/default/files/pliki/regulaminy/ncn_scholarships_in_projects_en.pdf)
Required documents:
For the list of the required documents, see the general announcement on the open positions in the Geoplanet Doctoral School (https://www.ing.pan.pl/en/education/geoplanet-doctoral-school/translate-to-english-rekrutacja). The list includes: 1) application to the doctoral school; 2) a copy of the master’s diploma; 3) a list of university marks; 4) CV; 5) a cover letter (1 A4 page maximum); 6) English language certificates (if the candidate possesses them); 7) at least 1 recommendation letter
Form of submitting documents:
Applications should be sent as one PDF file to the Doctoral School Coordinator via email: rekrutacja_ingpan@twarda.pan.pl and to the PI via email: ndkuligi@cyf-kr.edu.pl. In the title of the email please indicate „SKIP”.
For additional information, please contact:
Dr. hab. Edyta Zawisza – the Doctoral School Coordinator at IGS PAS: ezawisza@twarda.pan.pl
Dr. Artur Kuligiewicz – PI: ndkuligi@cyf-kr.edu.pl
Informacja RODO:
Zgodnie z art. 13 ust. 1 i ust. 2 ogólnego rozporządzenia o ochronie danych osobowych z dnia 27 kwietnia 2016 r. Instytut Nauk Geologicznych PAN informuje, że:
• Administratorem danych osobowych przesłanych przez kandydatów (dalej: dane osobowe) jest Instytut Nauk
Geologicznych Polskiej Akademii Nauk z siedzibą w Warszawie ul. Twarda 51/55 00-818;
• Kontakt do inspektora ochrony danych osobowych w ING PAN: ingpan@twarda.pan.pl – w temacie prosimy
wpisywać RODO i rodzaj sprawy;
• Dane osobowe przetwarzane będą w celu rekrutacji na podstawie art. 6 ust 1 pkt b RODO;
• Odbiorcą danych osobowych będzie Instytut Nauk Geologicznych PAN;
• Dane osobowe nie będą przekazywane do państwa trzeciego/organizacji międzynarodowej;
• Dane osobowe będą przechowywane przez okres do sześciu lat do celów wynikających z prawnie
uzasadnionych interesów realizowanych przez administratora danych osobowych;
• Każdy zgłaszający ma prawo dostępu do treści swoich danych oraz prawo ich sprostowania, usunięcia, ograniczenia przetwarzania, prawo do przenoszenia danych, prawo wniesienia sprzeciwu, prawo do cofnięcia zgody w dowolnym momencie bez wpływu na zgodność z prawem przetwarzania, którego dokonano na podstawie zgody przed jej cofnięciem;
• Kandydat ma prawo wniesienia skargi do PUODO gdy uzna Pani/Pan, iż przetwarzanie danych osobowych jej/jego dotyczących narusza przepisy ogólnego rozporządzenia o ochronie danych osobowych z dnia 27 kwietnia 2016 r.;
• Podanie przez kandydata danych osobowych jest niezbędne do przeprowadzenia rekrutacji i udziału w niej. Kandydat jest zobowiązany do ich podania a konsekwencją niepodania danych osobowych będzie nierozpatrzenie kandydatury
