Alvar Soesoo

Tallinn University of Technology, Institute of Geology, Faculty Member

University of Tartu, Institute of Ecology and Earth Sciences, Department of Geology, Visiting Professor

Followers

171

Following

Co-authors

Public Views

xx
Address: https://www.etis.ee/portaal/isikuCV.aspx?TextBoxName=soesoo&PersonVID=36775&lang=en&FromUrl0=isikud.aspx

less

InterestsView All (16)

Uploads

Papers by Alvar Soesoo

On the Petrochemistry of Precambrian Quartz-Feldspar Gneisses (Leptites) of Estonia and Suursaari (Gogland), RSSFR

Petrochemical composition of quartz-feldspar (Q-Fsp) gneisses from 24 drill cores of the South-Es... more Petrochemical composition of quartz-feldspar (Q-Fsp) gneisses from 24 drill cores of the South-Estonian, West-Estonian, and Tallinn areas, and from nine outcrops on Suursaari, RSSFR, (53 samples in all) have been analysed. Q-Fsp gneisses of the Estonian basement and Suursaari are fine grained, grayish-red rocks. Principal minerals are quartz, plagioclase, potash feldspar, and biotite; the additional minerals are hornblende, muscovite, epidote, apatite, ore minerals, garnet, and orthite. Q-Fsp gneisses of Suursaari differ from those of the other areas in their higher content of quartz and plagioclase and lower content of potash feldspar and biotite. Differences can be also observed between the chemical composition of the rocks of different areas. The quartzfeldspar gneisses of the Tallinn area and Suursaari have comparatively higher contents of silica oxide and lower contents of aluminium, magnesium, and calcium oxides. High content of potash is characteristic of all Estonian Q-Fsp gneisses. Variation diagrams based on the Niggli main value show similarity of al, fm, ¢ and alk dynamics of the Tallinn and West-Estonian areas. The plots of the samples corresponding to these two areas also overlap on Neelov's diagram (a-b). To classify the Q-Fsp gneisses of the Tallinn area according to their chemical composition, cluster analysis has been used. The best clustering results were obtained using Niggli values as input data: two main groups were distinguished and one of them fell into three subgroups. Comparing the chemical composition of the Q-Fsp gneisses of Estonia and Suursaari with their analogues from Finland, the similarily of the rocks of Pellinki and Kiuruvesi areas to the Q-Fsp gneisses of Suursaari and partly also to the gneisses of the Tallinn area can be observed.

Download

Divergent double subduction: Tectonic and petrologic consequences: Reply

Geology, 1998

TURBIDITE PROVENANCE An implication of the proposed model is that multiple subduction zones shoul... more

Modelling Impacts of Groundwater Flow on Borehole Heat Exchangers: Lessons Learned from Estonia

Production of geothermal energy relies heavily on subsurface properties. In low-enthalpy geotherm... more Production of geothermal energy relies heavily on subsurface properties. In low-enthalpy geothermal regimes, thermal energy extracted with a borehole heat exchanger (BHE) is the subsurface heat conducted from the rock and grout to the BHE fluid. No subsurface fluids are pumped in or out of the BHE system in the process. However, groundwater flow can bring warm or cold fluid from the surroundings which changes the temperature profile in the well and the vicinity and thus it can affect well heat production.The geology in Estonia provides a good opportunity to study the groundwater influence on the BHE systems. In Estonia, several hundred meters thick Lower Palaeozoic sedimentary rock sequence is mostly covered by relatively thin Quaternary sediments, while the underlying Lower Proterozoic crystalline basement rocks occur at depths from 150 m in North Estonia to over 600 m in South Estonia. The main groundwater aquifers are confined to the Palaeozoic sedimentary rocks. In North Estonia, the main groundwater aquifers overlying the crystalline basement rocks are Gdov, Voronka, Cambrian-Vendian, Ordovician-Cambrian, and Silurian-Ordovician aquifers. Those aquifers have different thermogeological and hydrogeological parameters shown by several groundwater hydrogeological and hydrodynamic studies and modelling. Only a few geothermal energy studies have been conducted in the Estonian geological setting and the groundwater effects on the geothermal energy budget on the shallow to medium depth geothermal energy systems have not yet been studied in detail.In this study, we parametrized different hydraulic conditions to compare how the groundwater flow velocity impacts the thermal energy yield of the geothermal system. We modelled single BHEs of lengths of 400 m, 500 m and 1000 m and a BHE field of ten 400 m wells at three sites across Estonia. 400 m wells have a U-tube type heat collector grouted with bentonite clay and the 500 m and 1000 m wells have a coaxial heat exchanger of plastic pipe or a vacuum-insulated tube (VIT), respectively. Our results demonstrate that 1) the thermogeological parameters of the area, such as subsurface temperature and thermal conductivity, are the most significant factor in the thermal energy yield of the wells and 2) at all sites, shallow BHEs are sensitive to the added groundwater flow, whereas 1-kilometer-deep coaxial wells with VIT are the least sensitive to the addition. An interesting highlight is that the increase in the thermal energy yield is not consistent at different locations with the groundwater flow variation. At sites where the aquifers are located deep with respect to the borehole length, an increase in groundwater flow velocity brought more advantages than at sites where permeable layers are distributed more evenly or near the top of the geothermal well.

Outlines of the Precambrian basement of Estonia

Estonian Journal of Earth Sciences, 2004

The crystalline basement of Estonia can be subdivided into two major geological units-North Eston... more The crystalline basement of Estonia can be subdivided into two major geological units-North Estonian amphibolite and South Estonian granulite complexes. The amphibolite facies terrain consists of a sequence of metavolcanics and-sediments, which resemble those of the island arc sequences in southern Finland. The South Estonian granulites, probably belonging to the Belarus-Baltic Granulitic Belt, show the peak metamorphism conditions of about 800 °C and 5-6 kbar. U-Pb isotopic data demonstrate that the Estonian basement has formed during the Palaeoproterozoic, 1.9-1.8 Ga ago and is composed of magmatic, volcanic, and sedimentary components across major structural zones. The granulite metamorphism postdates these ages (1.79-1.73 Ga). The youngest igneous rocks in the basement belong to the Fennoscandian Palaeo-Mesoproterozoic Rapakivi Province and include the composite Riga batholith, as well as at least five minor stock-like porphyritic K-granite plutons (ca. 1.6 Ga).

Download

U–Pb geochronology of detrital zircon from the Ediacaran and Cambrian sedimentary successions of NE Estonia and Volyn region of Ukraine: Implications for the provenance and comparison with other areas within Baltica

Precambrian Research, Jul 1, 2023

Anto Raukas – an encyclopaedist in Estonian Quaternary geology

Estonian Journal of Earth Sciences, 2005

Download

Erratum: Geochemistry, mineral chemistry and pressure–temperature conditions of the Jõhvi magnetite quartzites and magnetite-rich gneisses, NE Estonia (Estonian Journal of Earth Sciences, 2021, 70, 2, 71–93)

DOAJ (DOAJ: Directory of Open Access Journals), Aug 1, 2021

Hindered settling and the formation of layered intrusions

EGU General Assembly Conference Abstracts, Apr 1, 2015

Download

Graptoliit-argilliidi leostuvus merevees ja sellest tulenev keskkonnaohtlikkus

Pyroclastic Sanidine in the Lower Palaeozoic Bentonites – A Tool for Regional Geological Correlations. Püroklastiline sanidiin Alam-Paleosoikumi bentoniitides – regionaalstratigraafia uus töövahend

authigenic potassium feldspar can reach more than 80% and illite-smectite is the second main comp... more authigenic potassium feldspar can reach more than 80% and illite-smectite is the second main component.  K-bentonites: illite-smectite is the dominating authigenic mineral (Fig. 2B) (Somelar et al. 2009, 2010). Rarely occur K-bentonites in which the contents of other components are so low that they cannot be seen on XRD patterns. Commonly K-feldspar and/or kaolinite accompany the main illite-smectite.  Al-bentonites contain much of kaolinite (Fig. 2C) and are common in deep shelf sediments in Latvia and Lithuania. Content of Al 2 O 3 exceeds 30% and K 2 O contents are often below 3-4%. Presence of kaolinite in bentonites is easily established by the 7.15Å reflection. In the Ordovician Kinnekulle Bentonite kaolinite appears in southernmost sections of Estonia (Valga and Taagepera), (Kiipli et al. 2007, Somelar et al. 2009). In Silurian Telychian bentonites the northernmost findings of kaolinite were registered in Kaugatuma core (Fig. 1).  Mg-bentonites contain much of corrensite (chlorite-smectite). MgO contents can exceed 12%. Other major minerals are illite-smectite and K-feldspar. This type of bentonites is distributed in the transitional zone between the shallow and deep shelf in the sediments of the Pirgu Stage (Hints et al. 2006).  Sulphur-rich pyritic bentonites (pyrite content in a bulk sample above 30%) occur in organic-rich shales. In old cores these ash beds resemble weathered pyrite layers as the pyrite mixed with clay minerals oxidizes easily in core boxes. Pyrite-rich bentonites can be found in the Dobele Formation in Latvia and Lithuania (Fig. 2D). Bentonites in shales and marlstones are often sulphur-rich, too, concentrations reaching up to 8% (Paper V Fig. 6)  Hematite-rich bentonites (Fe 2 O 3 >10%) occur in red and green coloured shaly sediments. These bentonites are characterized by dark violet colour. Other main minerals are represented by illite-smectite, K-feldspar and kaolinite assemblage. Bentonites of this type are frequent in Telychian deep shelf and transition zone sediments of South Estonia and Latvia. The following example demonstrates how the Nurme Bentonite (ID731), a bed of particular volcanic eruption, reveals compositional changes according to the facies zone: it is feldsphatic tuff in Nurme core, Al-bentonite in Aizpute, Ohessaare and Ventspils cores, hematite-rich bentonite in Kihnu and Viki cores, K-bentonite with kaolinite and K-feldspar admixture in Ruhnu core. The listed bentonite types form a variety of transitional compositions, only pyrite and hematite do not coexist. Sometimes the volcanic material is mixed with sedimentary terrigenous and carbonate material (quartz, illite, chlorite, calcite, dolomite). Minor authigenic components recorded in some bentonites are barite, chalcopyrite, halite, goyazite-florencite and anatase. Authigenic apatite may occur in some layers. Authigenic formation of bentonite minerals is sensitive to the environmental conditions and carries useful information for reconstructing of sedimentary-diagenetic processes. Especially good results can be achieved by tracing compositional variations along correlated ash beds (Kiipli et al. 1997, 2007). Bentonites contain also a small amount of pyroclastic fragments of magmatic phenocrysts (sanidine, biotite, quartz, apatite, zircon).

Download

U-rich graptolite shales of Baltoscandia

Geochimica et Cosmochimica Acta Supplement, 2003

Download

Insights on the tectonic styles across Estonia using satellite potential fields derived from WGM-2012 gravity data and EMAG2 magnetic data

&amp;amp;lt;p&amp;amp;gt;The nature of the Estonian crust was studied using global topogr... more &amp;amp;lt;p&amp;amp;gt;The nature of the Estonian crust was studied using global topography, magnetic data, and gravity data to estimate its tectonic regime. The Estonian Precambrian crystalline basement, composed of Paleo- to MesoProterozoic metamorphic and igneous rocks, is covered by a Paleozoic sedimentary rock deposit 100&amp;amp;amp;#8211;780 m thick. To visualize crustal sources of the Estonian basement, we employed spectrum analysis of magnetic and gravity data, as well as two-dimensional (2D) forward modeling of gravity data. The gravimetric data was also evaluated to identify the depth of the Moho and Conrad discontinuities in Estonia. The magnetic data has also been evaluated to calculate the Curie point depth, which was then utilized to predict heat flow values inside the research zone. The subsurface of Estonia is divided into six petrological-structural zones: Tallinn, Alutaguse, Johvi, West-Estonian, Tapa and South-Estonian. To assess the structural variations of the crust at these locations, profiles of topographic, gravity, magnetic and heat flow data were constructed in each of the petrological-structural zones. The spectrum analysis and 2D gravity forward models yielded residual and regional gravity anomaly maps that show a significant amplitude potential maximum across the precambrian Rapakivi granitoid plutons and the Paldiski-Pskov tectonic zone. The Curie point depth reveals values ranging from 7 to 26 km, whereas the Moho depth suggests values ranging from 48 to 72 km and the Conrad depth values ranging from 14 to 20 km.&amp;amp;lt;/p&amp;amp;gt;

A ca.1.89 Ga magmatic complex in eastern Lithuania: a link connecting with the domains in Estonia and the Bergslagen terrane in Sweden

EGUGA, Apr 1, 2018

Efficient exhumation of (ultra) high-pressure rocks by slab extraction

EGU General Assembly Conference Abstracts, Apr 1, 2015

Download

Internal Geochemical Stratification of Bentonites (Altered Volcanic Ash Beds) and its interpretation

Redox-sensitive trace metal hyper-enrichment in Tremadocian Alum Shale (graptolite argillite) in northwestern Estonia, Baltic Palaeobasin

Chemical Geology

Amalgamation of the Qiangtang terranes, central Tibet, and new insights into the mechanism of exhumation of high-pressure rocks

Geotectonic Research, 2015

Assessing the geochemical variability of oil shale in the Attarat Um Ghudran deposit, Jordan

Estonian Journal of Earth Sciences, 2016

The Cretaceous to Palaeogene oil shale (OS) of Jordan is predominantly calcareous mudstone with i... more The Cretaceous to Palaeogene oil shale (OS) of Jordan is predominantly calcareous mudstone with intervals of mostly siliceous minerals, quartz and cristobalite-tridymite. Oil shale is rich in organic sulphur and trace elements. According to preliminary micropalaeontological data, the OS succession of the studied area, the south-central part of the Attarat Um Ghudran (AUG) deposit in central Jordan, is of Maastrichtian age. A representative collection of 392 samples from 9 drill cores reliably characterizes the sequence of the OS seam, on average 70 m thick. The composition of AUG OS varies significantly. The major compounds CaO and SiO 2 range within 3-70 wt% and 10-50 wt%, respectively, and also the contents of organic matter, MgO, P 2 O 5 , Al 2 O 3 and S change. The concentrations of metals (especially Zn, V, Cr, Ni and Mo) change many dozens of times in the cross section. The aim of our statistical analysis was to determine the most significant OS types and their positions in the OS sequence. Two multivariate statistical analysis methods, principal components analysis (PCA) and hierarchical clustering of PCA groups, gave an interpretable result. Four principal components account for 88.6% of data variability. Variation in six main chemical components or groups of components is reflected in parameters of the four principal components. The component PC1 accounts for 47% of the data variance, expressing the highest correlation with organic matter, S, Cr, Cu, Ni, Zn, Mo, and PC2 accounts for 22.82% of the data variability, being strongly correlated with TiO 2 , Al 2 O 3 , Fe 2 O 3 , SiO 2 and K 2 O and negatively correlated with CaO. The next two significant component groups express covariance with CaO and MgO. The applied statistical analysis proves to be a powerful tool for the interpretation of the chemically variable structure of the OS unit when using a representative enough sample collection. In the complex study of the OS unit, variation in the chemical composition is of interest, especially in the context of genetic and mining aspects.

Download

Reconstructing the Provenance, Tectonic Setting and Paleoweathering of Lower Paleozoic Black Shales from Northern Europe

Geological Society of America Abstracts with Programs

Karl Orviku 100; pp. 133–134

Proceedings of the Estonian Academy of Sciences. Geology, 2003

Download

Alvar Soesoo

Uploads

Papers by Alvar Soesoo

Log In