CONFERENCEHead of the Unit
Asoc. prof. Ģirts Stinkulis
Ģirts Stinkulis primarily conducts research in the fields of sedimentology and economic geology. In recent years, he has also focused on the study of crystalline basement rocks and ores. He is the author of publications on the formation conditions of Devonian siliciclastic deposits, as well as on the ancient soils of this period. Additionally, he is a co-author of books on various types of mineral resources in Latvia.
Research
The age of Pre-Quaternary rocks in Latvia is 1.8 billion to 150 million years. The oldest of these rocks form the solid foundation of the Baltic States – the crystalline basement – but the newest ones are found in the sedimentary rock cover.
Studies of the ancient rocks cover a variety of areas.
Nowadays, there are active studies of the Devonian sedimentary rocks (400-360 million years old) and vertebrate fossils, which are widespread in the Baltic States, available in outcrops and quarries. As a result, it has been established that Latvia and a wide area in its vicinity during this ancient time was covered by a shallow inland sea, in which large river deltas and estuaries often developed. Diverse representatives of the fauna lived in the seas and estuaries, including fish, from which the first tetrapods evolved. The transfer and accumulation of sediments, as well as the living environments of organisms, were affected by strong tidal currents. The climate at that time was warm, but variable – from relatively humid to dry. The events of the retreat of the sea are evidenced by ancient soils with plant root structures. Research by Latvian geologists and geology students allows to increasingly reconstruct these ancient events in the territory of the Baltic States and link them with global events of plate tectonics, climate change and even natural disasters.
In the ancient sedimentary cover of Latvia there are mineral resources – dolomite, clay, quartz sand, limestone, gypsum, etc. Geologists in their research cooperate with the Riga Technical University and mining companies. In the present changing times the geological knowledge allows to find out where to look for new resources, what is their quantity and quality.
It has been supposed that there are no ore resources in Latvia, however, the deep-embedded crystalline rock contains rich iron ores and many other metals. The true prospects for ores are very vague due to the lack of factual material. Currently, research on the prospects of crystalline basement ores in Latvia has been renewed and is actively underway. New, precise analyses are being carried out on samples of cores from previously obtained boreholes. Deep-embedded rocks and potential ore formations are "scanned" with the help of geophysical methods. These studies also help to clarify the processes of formation and secondary changes of the rocks from the crystalline basement.
Cooperation partners abroad: Uppsala University, University of Tartu, Tallinn University of Technology, Vilnius University, University of Wrocław, etc.
Important publications:
Ahlberg P.E., Clack J.A., Luksevics E., Blom H., Zupins I. 2008. Ventastega curonica and the origin of tetrapod morphology. Nature, 453: 1199-1204.
Beznosov, P.A., Clack, J.A., Lukševičs, E., Ruta, M., Ahlberg, P.E. 2019. Morphology of the earliest reconstructable tetrapod Parmastega aelidae. Nature, 574: 527-531.
Lukševics E., Lebedev O., Mark-Kurik E., Karatajūtė-Talimaa V. 2009. The earliest evidence of host-parasite interactions in vertebrates. Acta Zoologica (Stockholm), 90 (Supplement 1): 335-343.
Pipira, D., Ķeipāne, L., Stinkulis, Ģ., Vircava, I., Martma, T. 2023. Dolocretes in the uppermost Famennian to Mississippian siliciclastic deposits (Šķervelis Formation, Latvia). Estonian Journal of Earth Sciences, 72 (2): 211–225.
Stinkulis, Ģ., Lukševičs, E., Reķe, T. 2020. Sedimentology and vertebrate fossils of the Frasnian Ogre Formation, Gurova outcrops, Eastern Latvia. Estonian Journal of Earth Sciences, 69 (4): 248-261.
Important projects
Project of Latvian Council of Science lzp-2018/2-0231 „Influence of tidal regime and climate on the Middle-Late Devonian biota in the epeiric Baltic palaeobasin” (2018-2020), leader Ervīns Lukševičs
Natural Environment Research Council (Great Britain), project No NE/PO13090/1 “Skull evolution and the terrestrialization and radiation of tetrapods” (2017-2020), participant Ervīns Lukševičs
EU HORIZON 2020 1.1. project “Tracking our ancestors across the Devonian world: a new multidisciplinary approach to the origin of tetrapods” (2021-2026), researcher Ervīns Lukševičs
Project of Latvian Council of Science lzp-2023/1-0278 “Ore potential of metal-bearing crystalline basement rocks in central and eastern Latvia” (2024-2026), leader Ģirts Stinkulis
Project of Latvian Council of Science lzp-2024/1-0061 “Late Famennian tetrapods from the equator to the Devonian Antarctic circle: diversification and paleoecology” (2025-2027), leader Ervīns Lukševičs
Participants of the Summer School in Palaeontology organized by Professor Ervīns Lukševičs (Department of Geology, UL Faculty of Science and Technology) and including geology students, are conducting research on Devonian vertebrate fossils and collecting the fossils in the Pavāri outcrop on bank of the Ciecere River.
Samples of deep-seated iron ores in the Gardene borehole core storage. Geologists of the University of Latvia in collaboration with Latvian Environment, Geology and Meteorology Centre take samples of these ores to conduct a new mineralogical, petrographic, and chemical analyses for determination of the amount and distribution of iron and other metals.
A sample of iron ore from the Staicele deposit. The ancient bedrock ores belong to the banded iron ore type. The ore mineral magnetite dominates in the black layers, and quartz in the light layers.
Geology Master's students in the "Economic Geology" study course get acquainted with the types of limestones and their properties at the place of their extraction.
The description of thin-sections is a significant method in the study of both sedimentary rocks and deeply embedded igneous and metamorphic rocks. A thin section is a 0.02-0.03 mm thick rock slice glued to glass. In a microscope, polarized light can be used to distinguish minerals, as well as to clarify their origin and later changes. This picture shows Devonian sandstone in thin-section: A – quartz; B – feldspars microcline and orthoclase; C – biotite (a type of mica).
Since 2024, geologists of the University of Latvia, Faculty of Science and Technology, together with several cooperation partners, have been leading the nomination procedure of candidates for the Latvian Geosite of the Year. They also prepare visual materials and organise educational events at the geosites. In the picture we see the Latvia Geosite of Year 2024 – Gūdu Cliffs – on the bank of the Gauja River.