My research interests
Early Earth environment as a cradle for emerging life
One of my research interests, and the most personally intriguing, is the reconstruction of early Earth environments in the context of origin of life. The environmental conditions of the Earth before 4 billion years ago are highly uncertain, largely because of the lack of a substantial rock record for this period. The composition of atmosphere and climate are still controversial. Howbeit, during this time interval, known as the Hadean, the young planet transformed from an uninhabited world to the one capable of supporting the first living cells. The intensively investigated Hadean detrital zircons provide the most available data about this period of Earth’s history. However, besides Hadean zircons, at least three other repositories of information could provide insights into Hadean environments:
1. First microorganisms were formed in a fluid environment. Probably, at initial stages of evolution they could not control the chemistry of intracellular liquid. It is therefore likely that present-day organisms retain some record of the primordial fluid in which the first cells arise.
2. The modern terrestrial volatiles inventory is known and assuming that the main source of the volatiles is chondritic meteorites, it is possible to estimate the aeronomical losses of gases through all Earth's history. Those losses were the most sufficient in Hadean and depended from the redox conditions of early atmosphere.
3. Geologic records on other planets, especially Mars, could provide analogs for processes on early Earth.
1. A.A. Novoselov, D. Silva, J. Schneider, P. Serrano, X. C. Abrevaya, M. S. Chaffin, M. S. Navarro, J. Conti, and C.R. de Souza Filho, 2016. New geochemical constraints on the Hadean environment from mineral fingerprints of prokaryotes // Submitted in Astrobiology.
2. A.A. Novoselov, P. Serrano, M.L.A.F. Pacheco, M.S. Chaffin, J.T. O'Malley-James, S.C. Moreno, and F.B. Ribeiro, 2013. From cytoplasm to environment: the inorganic ingredients for the origin of Life // Astrobiology 13(3), 294–302. DOI: 10.1089/ast.2012.0836.
3. A.A. Novoselov, and S.A. Silantyev, 2012. Matter balance in the atmosphere - hydrosphere - crust system of the early Earth // In ac. E.M. Galimov (eds.) Origin and Evolution of Biosphere, Moscow, Vernadsky Institute, 175-195, download PDF (7.23 MB)
Weathering and hydrothermal systems
The progress in simulations of early Earth environments can be achieved with detailed investigation of modern analogues. In first instance, any model must be able to reproduce the recent weathering and hydrothermal alteration. Therefore, modern weathering profiles and hydrothermal circulation systems can help to understand how the distinct environments evolved in past epochs and how their records could be modified with time. In our researches we compare the simulated results with long-term minerals dissolution experiments and detailed field observations. Using this approach we presented a novel interpretation of the Neoarchean and Paleoproterozoic paleosols and designed the universal model of oceanic hydrothermal circulation systems whose probably are the most conservative environment on our planet. Modeling is not some isolated theoretical technique, but it rather should be complemented with traditional field observations at any stage of simulations. Modeling approach coupled with other geologic methods provides better understanding of natural processes and reliable predictions.
1. A.A. Novoselov, and C.R. de Souza Filho, 2015. Potassium metasomatism of Precambrian paleosols // Precambrian Research 262, 67–83. DOI: 10.1016/j.precamres.2015.02.024.
2. N.A. Alfimova, A.A. Novoselov, V.A. Matrenichev, and C.R. de Souza Filho, 2014. Conditions of subaerial weathering of basalts in the Neoarchean and Paleoproterozoic // Precambrian research 241, 1–16. DOI: 10.1016/j.precamres.2013.09.013.
3. S.A. Silantyev, M.V. Mironenko, and A.A. Novoselov, 2009. Hydrothermal systems in peridotites of slow-spreading mid-oceanic ridges. Modeling phase transitions and material balance: Downwelling limb of a hydrothermal circulation cell // Petrology 17(2), 138-157, download PDF (817 KB)
In my work I apply various techniques of geochemical modeling; i.e., equilibrium thermodynamics, dissolution/precipitation kinetics, inverse modeling, Pitzer activity coefficients. Because my education background in physical oceanography, I am familiar with statistics and hydrodynamics that can be used to design complex reactive transport models. I have a many years experience of coding in Delphi (Pascal) and Fortran. I can quickly study any necessary computer language. In coding I specialize in optimization methods (Conjugate directions, Newton’s method, Golden search) and formation of databases (XML, SQL). Last years I am developing the software Crono intended for geochemical simulations. This simulation code can be potentially used in a number of geochemical problems, such as simulation of weathering and soil forming processes, ores genesis, metamorphism and many other applications in Earth sciences and industry. Its module structure and open source, unlike analogical software, allow its combination with other simulation codes. Besides, Crono can be used in courses about Geochemical Thermodynamics and Geochemical Modeling at the post-graduate level. Also I work with Phreeqc, FrezChem, Geocheq, Hch, Perple_X, Supcrt92, Theriak-Domino, and Thermoddem.
1. A.A. Novoselov, and C.R. de Souza Filho, 2013. CRONO – a code for simulation of chemical weathering // Computers & Geosciences 60, 168–175. DOI: 10.1016/j.cageo.2013.07.007.
2. A.A. Novoselov, S. Popov, and C.R. de Souza Filho, 2015. Evaluation of uncertainties in solid-aqueous-gas chemical equilibrium calculations // Computers & Geosciences 79, 118–128. DOI: 10.1016/j.cageo.2015.03.012.
I would like to participate in serious projects linked with application of numerical modeling methods in Earth sciences. Whereas I would prefer topics dedicated to reconstructions of early Earth environment, all other research opportunities in geochemistry or developing of simulation techniques, where I can apply my experience, are interesting for me.