Geothermal studies of the precambrian basement and phanerozoic sedimentary cover in Estonia and Finland

http://www.ester.ee/record=b1053471~S58*es

The relationship between fatigue and mirroring and expressing emotions

Käesoleva uurimistöö eesmärgiks on uurida, kas väsimusel ja unetundide arvul on seos emotsioonide peegeldamise ja väljendamise hinnanguskooridega. Katses analüüsiti 119 katseisikut, kes andsid hinnangut oma emotsioonide esitamisele. Leiti statistiliselt olulised seosed kurbuse ja hirmu peegeldamise ning kurbuse väljendamise ja katsele eelneva öö ja tavalise unetundide erinevuse vahel. Samuti olid statistiliselt olulised seosed hirmu peegeldamise ja vastikuse väljendamise ning keskmise unetundide vahel. Statistiliselt oluline erinevus leiti ka keskmiselt alla ja üle 7 tunni magavate katseisikute vahel, need, kes magavad regulaarselt alla soovitusliku piiri hindasid oma emotsioonide esitamise oskust madalamalt, kui üle 7 tunni magavad katseisikud. Järeldati, et uneaeg võib mõjutada emotsioonide peegeldamist ja väljendamist

Ground-penetrating radar study of the Rahivere peat bog, eastern Estonia

The current case study presents results of the ground-penetrating radar (GPR) profiling at one of the Saadjärve drumlin field interstitial troughs, the Rahivere bog, eastern Estonia. The study was conducted in order to identify the bog morphology, and the thickness and geometry of the peat body. The method was also used to describe the applicability of GPR in the evaluation of the peat deposit reserve as the Rahivere bog belongs among the officially registered peat reserves. Fourteen GPR profiles, ~ 100 m apart and oriented perpendicular to the long axis of the depression, covering the bog and its surrounding areas, were acquired. In order to verify the radar image interpretation as well as to evaluate the velocity of electromagnetic waves in peat, a common source configuration was utilized and thirteen boreholes were drilled on the GPR profiles. A mean value of 0.036 m ns–1 corresponding to relative dielectric permittivity of 69.7 was used for the time–depth conversion. Radar images reveal major reflection from the peat–soil interface up to a depth of about 4 m, whereas drillings showed a maximum thickness of 4.5 m of peat. Minor reflections appear from the upper peat and mineral soil. According to the borehole data, undecomposed peat is underlain by decomposed one, but identifying them by GPR is complicated. Mineral soil consists of glaciolimnic silty sand in the peripheral areas of the trough, overlain by limnic clay in the central part. The calculated peat volumes (1 200 000 m3) were found to exceed the earlier estimation (979 000 m3) that was based solely on drilling data. Ground-penetrating radar, as a method that allows mapping horizontal continuity of the sub-peat interface in a non-destructive way, was found to provide detailed information for evaluating peat depth and extent

Geological settings of the protected Selisoo mire (northeastern Estonia) threatened by oil shale mining

The protected Selisoo mire in northeastern Estonia is located above valuable oil shale resources, partly in the permitted mining area. We describe in detail the geomorphology and geological setting of the mire to understand the natural preconditions for its formation, development and preservation. We used the LiDAR-based digital elevation model for relief analysis, mapped the peat thickness with ground-penetrating radar and described the Quaternary cover through corings. Ridges, oriented perpendicular to the generally southward-sloping terrain, and shallow depressions at the surface of mineral soil have influenced mire formation and its spatio-temporal dynamics. The Quaternary cover under the mire is thin and highly variable. Therefore the mire is hydro­geologically insufficiently isolated from the limestone bedrock that is drained by the nearby oil shale mine and consequently the mining activities approaching the mire may have a negative influence on the wetland and proposed Natura 2000 site. Natura 2000 type wetlands, both protected or currently outside the nature reserves, cover a significant portion of the prospective oil shale mining areas. The distribution and resilience of those sites may significantly influence further utilization of oil shale resources

Small impact cratering processes produce distinctive charcoal assemblages

The frequency of crater-producing asteroid impacts on Earth is not known. Of the predicted Holocene asteroid impact craters of <200 m diameter, only ~30% have been located. Until now there has been no way to distinguish them from “normal” terrestrial structures unless pieces of iron meteorites were found nearby. We show that the reflective properties of charcoal found in the proximal ejecta of small impact craters are distinct from those produced by wildfires. Impact-produced charcoals and wildfire charcoals must derive from different heating regimes. We suggest that charcoal with specific reflective properties may help to recognize the meteoritic origin of small craters.Marie Sklodowska-Curie grant ImpChar, agreement no. 749157; the 2016 Barringer Family Fund for Meteorite Impact Research (Arizona, USA); National Science Centre Poland grants 2020/39/D/ST10/02675 and 2013/09/B/ST10/01666

Upper mantle velocity-temperature conversion and composition determined from seismic refraction and heat flow

International audience[1] We compile upper mantle P n velocities from seismic refraction/wide-angle reflection surveys in the southern Superior Province of the Canadian Shield and compare them with temperatures at the Moho deduced from heat flow data. Calculated Moho temperatures and P n velocities correlate well, showing that in this area, P n depends primarily on temperature. The obtained values of @V(P n)/@T depend weakly on the assumed value of Moho heat flow and are on the order of À6.0 Â 10 À4 ± 10% km s À1 K À1 , within the range of temperature derivatives obtained in laboratory studies of ultramafic rocks. Comparison between observed P n velocities and predicted values for several mineralogical models at Moho temperatures allows constraints on both the Moho heat flow and the shallow mantle composition. For all Moho heat flows, undepleted (clinopyroxene-rich) mantle compositions do not allow a good fit to the data. For depleted mantle compositions, temperatures consistent with the observed P n velocities correspond to values of Moho heat flow larger than 12 mW m À2. For our preferred Moho heat flow of 15 mW m À2 , the best fit mantle composition is slightly less depleted than models for average Archean subcontinental lithospheric mantle. This may be due to rejuvenation by melt-related metasomatism during the Keweenawan rifting event. The similarity in P n À T conversion factors estimated from this empirical large-scale geophysical study and those from laboratory data provides confidence in the absolute temperature values deduced from heat flow measurements and seismic studies. Citation: Perry, H. K. C., C. Jaupart, J.-C. Mareschal, and N. M. Shapiro (2006), Upper mantle velocity-temperature conversion and composition determined from seismic refraction and heat flow

Vertikaalsed maasoojussüsteemid

Õpiobjektis käsitletakse erinevate vertikaalsete maasoojussüsteemide olemust ning nende rajamist. Selgitavate tekstide juures olevad animatsioonid annavad lihtsustatud, kuid piltliku ettekujutuse vertikaalsete maasoojussüsteemide rajamise protsessist, avatud süsteemi mõjust ümbritsevale keskkonnale ning soojusvahetuse protsessist maasoojussüsteemide puhul

A ground-penetrating radar study of the Vaidasoo bog (Estonia) : no crater structure exists

Ground-penetrating radar (GPR) was used to analyse the circular Vaidasoo bog in northern Estonia. This was done to better understand its structure and origin, and to test the suggestion that Vaidasoo represents a meteorite impact structure. The combination of GPR with LIDAR data suggests that Vaidasoo bog is developed in a NW–SE oriented glacial tunnel valley where post-glacial hydrology is affected by glaciofluvial deposits. As no clear impact-modified bedrock features were identified and the circular bog does not mirror the topography of the bedrock, we conclude that the Vaidasoo structure does not represent a meteorite impact structure