Sou um geoquímico profundamente interessado em entender a evolução da Terra e seus diversos acoplamentos, ou “esferas”, incluindo a vida que habita o planeta. Compreender processsos naturais que conduzem à hierarquização (ou organização em diversos níveis) e ao surgimento de novos estados de complexidade é uma grande motivação para mim. Entre outras coisas, a minha pesquisa envolve a investigação de como importantes ciclos biogeoquímicos na superfície planetária interagem e se retro-alimentam. Tectônica, clima e a vida interagem de forma contínua e intrincada, propagando-se dos níveis atômico e molecular à enorme escala planetária. Essas interações podem deixar vestígios da sua história registrada em minerais que compõem certas rochas sedimentares, e este material é o meu principal objeto de estudo, seja ele natural ou sinteticamente produzido em laboratório.
Extended bio in English:
I did my PhD research at the University of Oxford, under the supervision of Nicholas Tosca (now Professor at the University of Cambridge). My research aimed at providing physico-chemical constraints on the growth conditions and morphology development of carbonate minerals (e.g., calcite) forming from alkaline lake waters. Carbonate minerals and carbonate rocks are widespread across the geological record and on the surface of the Earth, comprising important materials that allow us to probe deep into the Earth’s past environmental conditions. Calcite crystals, in particular, are known to occur in a variety of forms, and to complicate matters one given morphology may usually result from slightly different environmental processes on the planetary surface. Thus, one important question is whether or not a given morphology can be directly interpreted as a proxy for some specific environmental condition. My research touched on the questions above. The outcomes of these investigations bear not only implications for our deeper understanding about the chemical controls on carbonate mineral growth in alkaline lakes. They also carry implications for current hypotheses regarding potential prebiotic chemical conditions enabling the origin of life in these environments on the Early Earth, in the Hadean (roughly 4 Ga, four billion years ago).
Further to the experiences above, I have been a researcher working for over 16 years in the oil, gas and energy industry. There I have applied inorganic and isotopic geochemistry in chemostratigraphic studies, palaeoenvironment reconstruction, and investigations on the effects of diagenesis on the chemical and isotopic properties (as well as physical/textural) properties of reservoir rocks. All these studies carry fundamental implications for our understanding of fluid-rock interactions, whose required knowledge builds strongly on principles of thermodynamics and kinetics. These, in turn, are of paramount importance to any serious study in chemical sedimentology and/or aqueous geochemistry. Furthermore, these two disciplines are not only relevant to studies focussing on palaeoenvironment reconstruction or diagenesis. They are also fundamentally important for investigations in related and very current topics addressing some of humanity’s most pressing climatic and energy issues, such as geological Carbon Capture and Storage (CCS), geothermal energy, and any other research that may involve fluid and rock interactions.
In industry, I could extend my scientific interests to the search for solutions to rather applied geological problems, but I also have been able to develop a wider perception of our society’s demand for natural resources and for energy. Human society does not move forward without relying so much on Earth’s resources. And this is actually a general principle for all life, in such a way that this idea is connected with the broader underlying concepts regarding the onset of life itself. Interestingly, the growth of populations and of societies has some corresponding analogy with the growth of minerals: all consume resources from their surroundings to keep going. Yet, this surficial analogy may conceal an even more striking and fundamental principle.
I am keen to get involved in discussions on these and other topics and to engage in scientific outreach for the general public. For this latter purpose this blog was created about 10 years ago, where my goal has been to bring awareness and discussions for the general Brazilian public on issues concerning science and education.
Some selected scientific (peer-reviewed) publications:
- Pietzsch, R., Tosca, N.J., Gomes, J.P., Roest-Ellis, S., Sartorato, A.C.,L., Tonietto, S.N., 2022. The role of phosphate on non-skeletal carbonate production in a Cretaceous alkaline lake. Geochimica et Cosmochimica Acta, in press. doi: 10.1016/j.gca.2021.09.032
- Pietzsch, R., 2021. Comment on “Evaporitic carbonates in the pre-salt of Santos Basin – Genesis and tectonic implications”. Marine and Petroleum Geology, 104963. doi: 10.1016/j.marpetgeo.2021.104963
- Pietzsch, R., Tedeschi, L.R., Martins, D.O., Anjos, C.W.D., Vazquez, J.C., Figueiredo, M.F. 2020. Environmental conditions of deposition of the Lower Cretaceous lacustrine carbonates of the Barra Velha Formation, Santos Basin (Brazil), based on stable carbon and oxygen isotopes: a continental record of pCO2 during the onset of the Oceanic Anoxic Event 1a (OAE 1a) interval? Chemical Geology 535, 119457. doi: 10.1016/j.chemgeo.2019.119457
- Pietzsch, R., Martins, D.O., Tedeschi, L.R., Queiroz Neto, J.V., Figueiredo, M.F., Vazquez, J.C., Souza, R.S. 2018. Palaeohydrology of the Lower Cretaceous pre-salt lacustrine system, from rift to post-rift phase, based on elemental geochemistry, biostratigraphy and radiogenic strontium isotope data, Santos Basin, Brazil. Palaeogeography, Palaeoclimatology, Palaeoecology 507, 60–80. doi: 10.1016/j.palaeo.2018.06.043
- Freire, A.F.M., Leite, C.M.M., Oliveira, F.M., Guimarães, M.F., Milhomem, P.S., Pietzsch, R., D’Ávila, R.S.F. 2017. Fluid escape structures as possible indicators of past gas hydrate dissociation during the deposition of the Barremian sediments in the RecôncavoBasin, NE, Brazil. Brazilian Journal of Geology 47, 79–93. doi: 10.1590/2317-4889201720160090
- Pietzsch, Raphael, Patchineelam, Sambasiva R., Torres, João P.M. 2010. Polycyclic aromatic hydrocarbons in recent sediments from a subtropical estuary in Brazil. Marine Chemistry 118, 56–66. doi: 10.1016/j.marchem.2009.10.004
- Pietzsch, R., Polivanov, H., Silva, A.S., Alamino, R.C.J., Campos, T.M.P. 2009. Study on the interaction of heavy metals on farmland in Petropolis, Rio de Janeiro, Brazil. Geological Society, London, Engineering Geology Special Publications, 22, IAEG2006 Paper number 352. doi: 10.1144/EGSP22.I
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