LA-ICP-MS U-Pb dating of Carboniferous ash layers in the Cantabrian Zone (N Spain): stratigraphic implications

Seven centimetre-thick volcanic ash-fall layers interbedded within the thick Carboniferous successions of the Cantabrian Zone in northern Spain were dated by U–Pb zircon laser ablation inductively coupled plasma mass spectrometry across an interval ranging from Visean to Kasimovian, thus covering most of the Carboniferous period. All these ash layers occur in fossiliferous successions, allowing us to insert the radiometric data within a well-constrained biostratigraphic framework. Considering the analytical uncertainty, the obtained ages match the ages inferred from the conodont biostratigraphy established in the Mississippian succession (which hosts the oldest two ash layers, Visean in age), and the fusuline and mega- and microflora data from the strata hosting the Moscovian and Kasimovian (Westphalian–Stephanian) tonsteins. The age of a Langsettian tonstein along with data provided by several papers stating that in the Cantabrian Zone Langsettian floras were contemporaneous with lowermost Moscovian fusulines suggest that Langsettian floras could have been younger in Spain than in other areas. Our absolute ages provide new constraints not only for the correlation of the Carboniferous successions of the Cantabrian Zone with time-equivalent reference successions in other parts of the world but also for calibrating the Carboniferous global chronostratigraphic units based on marine fossils with the West European regional units

Assessment of Danger in the course of Filling a Car with Compressed Natural Gas

Import 23/07/2015Diplomová práce se zabývá bezpečností paliva CNG, především bezpečností při jeho plnění. V první části je zemní plyn porovnáván s ostatními palivy. V další části se práce zabývá právními a technickými předpisy pro vybavení plnicích stanic a prostor s přítomností automobilů na pohon CNG. V práci je popsán způsob plnění vozidel, hodnocení možnosti úniku a příklad výpočtu nebezpečné atmosféry při úniku. Na závěr práce jsou uvedena doporučení na zabezpečení jednotlivých garáží.This diplom thesis deals with the safety of CNG fuel, especially the safety of its implementation. In the first part is the natural gas compared to other fuels. The next part deals with legislative and technical equipment for filling stations and area with the presence of vehicles to CNG. The thesis describes how the performance of vehicles, evaluating the possibility of escape and a sample calculation dangerous atmosphere in the release. In conclusion are given recommendations on protection of individual garages.030 - Katedra požární ochranyvelmi dobř

SP Fig. 2. LA-ICP-MS U–Pb dating of Carboniferous ash layers in the Cantabrian Zone (N Spain): stratigraphic implications

SP FIg. 2. Stratigraphic section of the Santo Firme Coalfield reconstructed using information from IGME (1984) and Trell (1988). Fusuline Zones from Villa & Merino-Tomé (2016), palynologic Zones from Horvarth (1985) and stages and substages of Western European regional scale and Uralsare indicated

SP Fig. 1. LA-ICP-MS U–Pb dating of Carboniferous ash layers in the Cantabrian Zone (N Spain): stratigraphic implications

SP Fig. 1. Synthetic stratigraphic section of the Baleas and Alba Formation in the Las Baleas section with the location of samples BA-1 and BA-2. Conodont zones of the Baleas Formation and the base of the Alba Formation according García-Alcalde (1985). Conodont zones of the Alba Formation according Sánz-López & Blanco-Ferrera (2012)

Estimation of mean sedimentary rates. LA-ICP-MS U–Pb dating of Carboniferous ash layers in the Cantabrian Zone (N Spain): stratigraphic implications

SP Table 2. Estimation of mean sedimentary rates

Intrasediment gypsum in subtidal offshore carbonates as a witness of basin-wide evaporitic precipitation. The case of the southern Variscan foreland basin (mid-Carboniferous)

Widespread calcite and quartz pseudomorphs, interpreted as originally gypsum crystals, occur within hemipelagic calci-mudstone accumulated in subtidal offshore environments in the broad marine foreland basin developed on the southern flank of the Ouachita–Alleghanian–Variscan Orogen during mid- Carboniferous times,which acted as a marine corridor connecting the Panthalassa and Palaeo-Tethys Oceans during the Mississippian, and progressively narrowed during the assembly of Pangea. In this study, 67 outcrops of radiolaria-bearing calci-mudstone deposits that contain calcite and quartz pseudomorphs located in northern Spain and southern France were studied to constrain the gypsum spatial distribution and sedimentological features. The recognised microfacies indicate intrasediment gypsum precipitation, accompanied by less abundant bottom-grown precipitates and gypsum cumulates, in extensive offshore, probably several ten to a few hundred metres deep, basinal environments. Gypsumprecipitation took place during a short-lived temporal episode during the early Bashkirian time (Voznesenkian), which can be correlated, on the basis of benthic foraminifera, with the coastal (inter- to supratidal) gypsum evaporites identified in NW Africa (Tindouf and Reggan successions in Morocco and Algeria) that would represent the shallow-water counterparts. The occurrence of gypsum precipitates both in offshore hemipelagic calci-mudstones of the Variscan foreland basin and in inter- to supratidal environments of the epeiric Sahara Platform indicates that hypersaline conditions affected vast marine areas, roughly coinciding with the estimated age of closure of the Panthalassa and Palaeo-Tethys marine connection. Therefore, the studied succession represents the trace of a basin-wide evaporitic episode extending for hundreds of kilometres driven by foreland basin restriction, mid-Carboniferous sea-level fall and arid climate. This study provides new insights for the interpretation of gypsum precipitates in offshore marine environments encountered in the Phanerozoic and whose genesis is poorly understood