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

An aeolian or a glaciolacustrine record? A case study from Mieļupīte, Middle Gauja Lowland, northeast Latvia

In the Middle Gauja Lowland, northeast Latvia, dunes are distributed over a vast glaciolacustrine plain that formed during the retreat of the Fennoscandian ice sheet. Such a direct contact between aeolian and glaciolacustrine sediments can be used to infer depositional settings and decipher to what extent these sediments bear an aeolian component. Our proxies, although preliminary, reveal a limited range of variation in grain-size parameters, a significant presence of quartz grains with silica precipitation and matt-surface grains of various rounding degrees and massive structure combined with horizontal lamination. These are indicative of periglacial-aeolian depositional conditions in the foreland of the Linkuva ice-marginal zone. Sedimentary characteristics do not match a single luminescence date of 9.2±0.6 ka, which significantly postdates the minimum age of the Linkuva ice-marginal zone with 10Be ages between 15.4 and 12.0 ka. Whether deposition started directly after drainage of the Middle Gauja ice-dammed lake or if there is a gap of 2.8–6.2 ka is a matter of debate; only future studies at higher OSL resolution could resolve this

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