STOP 1: Lower Gauja spillway valley at Sigulda

I det här arbetet har linjär regression använts för att undersöka om olika sociala faktorer påverkar om elever får gymnasiebehörighet. Unders ökningen gjordes med kommunvis aggregerad data och faktorerna som undersöktes var utländsk bakgrund, försörjningsstöd, utbildningsnivå, arbetsl öshet, disponibel inkomst, lärartäthet, andel lärare med pedagogisk examen och skolornas kostnad. Statistiskt signikanta resultat erhölls för utländsk bakgrund, försörjningsst öd, utbildningsnivå, disponibel inkomst och lärartäthet. Enligt undersökningen påverkar utländsk bakgrund och försörjningsstöd gymnasiebeh örigheten negativt. Utbildningsnivå och disponibel inkomst påverkar den positivt. Lärartätheten påverkar gymnasiebehörigheten positivt om andelen lärare i svenska som andraspråk och modersmål inte överstiger 10,4 %. Resultaten för resten av de undersökta faktorerna var inte statistiskt signikanta och därför kan inget sägas säkert om dem utifrån den här undersökningen. Observera att inga slutsatser kan dras på individnivå. Det som kan sägas utifrån undersökningen är att i kommuner där en stor andel av befolkningen t.ex. får försörjningsstöd tenderar andelen elever som får gymnasiebehörighet att vara lägre

Seismites resulting from high-frequency, high-magnitude earthquakes in Latvia caused by Late Glacial glacio-isostatic uplift

AbstractGeologically extremely rapid changes in altitude by glacial rebound of the Earth crust after retreat of the Scandinavian Ice Sheet at the end of the last Weichselian glaciation influenced the palaeogeography of northern Europe. The uplift of the Earth crust apparently was not gradual, but shock-wise, as the uplift was accompanied by frequent, high-magnitude earthquakes. This can be deduced from strongly deformed layers which are interpreted as seismites. Such seismites have been described from several countries around the Baltic Sea, including Sweden, Germany and Poland.Now similarly deformed layers that must also be interpreted as seismites, have been discovered also in Latvia, a Baltic country that was covered by an ice sheet during the last glaciation. The seismites were found at two sites: Near Valmiera in the NE part and near Rakuti in the SE part of the country. The seismites were found in sections of about 7 m and 4.5 m high, respectively, that consist mainly of glaciofluvial and glaciolacustrine sands and silts. At the Valmiera site, 7 seismites were found, and at the Rakuti site these were even 12 seismites.The two sections have not been dated precisely up till now, but lithological correlations and geomorphological characteristics suggest that the sediments at the Valmiera site cannot be older than 14.5 ka. Because the accumulation of the section did not take more than about 1000 years, the average recurrence time of the high-magnitude (M ≥ 4.5–5.0) earthquakes must have been maximally only 100–150 years, possibly only 6–7 years. The sediments at Rakuti must also have formed within approx. 1000 years (17–16 ka), implying a recurrence time of high-magnitude earthquakes of maximally once per 100–200 years

APPLICATION OF UNMANNED AERIAL VEHICLES FOR GLACIER RESEARCH IN THE ARCTIC AND ANTARCTIC

Unmanned aerial vehicles or drones are nowadays widely used in a broad field of scientific and commercial applications. Despite this, it is quite a new method for glacier mapping in polar regions and has a lot of advantages, as well as disadvantages over more classical remote sensing instruments. Here we examine the main issues associated with the application of drones for glacier research from our experience in Iceland, Greenland and the Antarctic. We use DJI Phantom series drones for the obtaining of aerial photographs and produce digital surface models (resolution of 8 – 16 cm) and orthomosaics (resolution of 2 – 4 cm) for glacier mapping. Several issues related to the ground control points, geolocation using Global Navigation Satellite System receiers and creation of final products are addressed as well. We recommend the further use of drones in remote polar areas because it allows obtaining very high-resolution orthomosaics and digital surface models that are not achieved by other methods. Short summer season, raw weather with precipitation and winds, limited drone flight duration and problems with connection cables are the main issues everyone can encounter working in polar regions but all issues can be restricted with careful planning and readiness to gather data whenever it is possible during all field campaign

Fine-grained quartz from cryoconite holes of the Russell Glacier, southwest Greenland – a scanning electron microscopy study

Funding Information: Prof. Albertas Bitinas (Klaipėda) and Prof. Petras Šinkūnas (Vilnius) are thanked for valuable comments, which improve the final version of the manuscript. Research was supported by the SIA SunGIS (E. Kalińska-Nartiša), by the ERAF project No. 1.1.1.2/ VIAA/1/16/118 (K. Lamsters) and by University of Latvia project “Climate change and sustainable use of natural resources” (No. AAP2016/B041).We thank Reinis Pāvils for field assistance. Publisher Copyright: © Baltica 2017.The western ablation zone of the Greenland ice sheet is darker than the surrounding ice, because a higher amount of fine-grained particles, known as a cryoconite, occur. To date, biotic cryoconite components have gained a lot of attention, in contrast with mineral components, which have been studied to a limited extent. In this study, fine-grained quartz grains from the cryoconite holes of the Russell Glacier, southwest Greenland are, therefore, examined. Authors use scanning electron microscope to elucidate shape, surface character and origin of these mineral quartz particles. Triangular-faceted, sharp-edged grains dominate in most of the investigated samples, and originate from local sources, where grain-to-grain contact in the ice prevail. Grains with smooth corners and edges result from chemical weathering in meltwater of alkaline pH, in which quartz solubility significantly increases. However, part of these rounded grains is due to mechanical abrasion by wind action. Postsedimentary frost action is visible through grains entirely or partially covered by scaly-grained encrustation. Local processes and sources are largely responsible for aforementioned grain outlines. However, few grains with bulbous silica precipitation argue for a dry and warm climate, and distant, out-of-Greenland origin.publishersversionPeer reviewe