Search results for "dating"
showing 10 items of 288 documents
Historical mortar: luminescence from fine grain quartz
2010
Within the framework of a research programme aimed at the chronological reconstruction of the structures belonging to the architectonic complex of San Francesco alla Collina of Paternò (Catania, Italy), a procedure was carried out using thermoluminescence (TL) and optically stimulated luminescence (OSL) dating, respectively on terracotta bricks and mortar from the same sampling points. The primary methodological aim was to extend the application of luminescence dating techniques to mortar from historical buildings. Because the TL dating method dates the last firing of bricks, it offers a terminus post quem: the results give the period in which they were manufactured. The possibility that th…
Determining irrigation needs of sorghum from two-source energy balance and radiometric temperatures
2011
Abstract. Estimates of surface actual evapotranspiration (ET) can assist in predicting crop water requirements. An alternative to the traditional crop-coefficient methods are the energy balance models. The objective of this research was to show how surface temperature observations can be used, together with a two-source energy balance model, to determine crop water use throughout the different phenological stages of a crop grown. Radiometric temperatures were collected in a sorghum (Sorghum bicolor) field as part of an experimental campaign carried out in Barrax, Spain, during the 2010 summer growing season. Performance of the Simplified Two-Source Energy Balance (STSEB) model was evaluated…
Sapphire-bearing magmatic rocks trace the boundary between paleo-continents: A case study of Ilmenogorsky alkaline complex, Uralian collision zone of…
2021
Abstract Metamorphic gem corundum (mainly ruby) deposits are robust indicators of continent-continent collision processes. However, a systematic link of primary magmatic blue sapphire occurrences to orogenic belts is less understood. An example is the Ilmenogorsky alkaline complex, within the Ilmen Mountains region and part of the Uralian orogenic belt. The mobile belt is a product of the collision among Kazakhstania, Laurussia, and Siberia continents prior to the closure of the Paleo-Uralian ocean and formation of the Laurasia supercontinent (330–250 Ma). It is believed that the alkaline complex became inсluded into the separate Sysertsk-Ilmenogorsk microcontinent with unconstrained border…
Young ages from old garnet in the polyphase metamorphic terrane of the Limpopo Belt, South Africa
2020
Abstract The P–T–t path of high-grade metamorphic rocks is significant for understanding vertical motions and heating of the crust. In general, garnet is used to constrain P–T paths and metamorphic zircon is used to obtain t for different metamorphic stages. However, this approach may be complicated by polyphase tectonothermal events. The Central Zone of the Limpopo Belt in South Africa is a complex Precambrian metamorphic terrane that has experienced three distinct high-grade metamorphic events at 3.22 Ga (M1), 2.62 Ga (M2), and 2.02 Ga (M3), based on zircon dating. A previous investigation of a metapelite enclave in the Bulai pluton in the Central Zone showed that metamorphic zircon in th…
Evolution of Pan-African island arc assemblages in the southern Red Sea Hills, Sudan, and in southwestern Arabia as exemplified by geochemistry and g…
1991
Kr6ner, A., Linnebacher, P., Stern, R.J., Reischmann, T., Manton, W. and Hussein, I.M., 1991. Evolution of Pan-African island arc assemblages in the southern Red Sea Hills, Sudan, and in southwestern Arabia as exemplified by geochemistry and geochronology. In: R.J. Stern and W.R. van Schmus (Editors), Proterozoic Crustal Evolution in the Late Proterozoic. Precambrian Res., 53:99-117. We report Rb-Sr whole-rock and zircon ages for metavolcanic and plutonic associations in the southeastern part of the Red Sea Hills, Sudan, and show that these rocks constitute one of the earliest Pan-African arc assemblages within the Arabian-Nubian shield. The remarkable similarity in geochemistry and age bet…
230Th/U-dating of carbonate deposits from ancient aqueducts
2016
Abstract Carbonate deposits in aqueducts, known as calcareous sinter, can reach a considerable thickness and are commonly annually laminated. Environmental and palaeoclimate proxies measured in calcareous sinter samples, such as stable oxygen and carbon isotopes and trace elements, can provide important high-resolution information on hydrological conditions, temperature, and local precipitation in the catchment area of an aqueduct. In order to utilize the proxy data for palaeoclimate reconstruction, the sinter deposits must be dated by annual laminae counting and more precisely by 230 Th/U-dating. The major problem of 230 Th/U-dating of calcareous sinter in aqueducts is the relatively large…
U-Pb zircon and Sm-Nd dating of Moldanubian H P /H T granulites from South ohemia, Czech Republic
1994
Conventional multigrain U-Pb systematics of zircon and single-grain evaporation data of zircons in combination with Nd model ages are presented for pyroxene-free, felsic, garnetiferous granulites and orthopyroxene-bearing granulites of felsic, mafic and intermediate composition from the Blansky Les mountains granulite complex, S Bohemia. Zircons from mafic and intermediate granulites yield Concordia intercept ages between 346 ± 5 and 351 ± 6 Ma as well as a single-grain evaporation age of 346 ± 12 Ma. These ages define the time of Variscan high-grade metamorphism in S Bohemia and are supported by an internal Sm-Nd garnet-zircon-plagioclase-whole rock isochron age of 343 ± 21 Ma. Euhedral zi…
Sequential leaching of silicified Archaean carbonates: A Rb-Sr, Sm-Nd and Pb-Pb isotopic contribution to their tectonic-thermal history (Kaapvaal Cra…
2021
Abstract Sequential leaching was completed by successive interactions of ultra-pure H2O, HAc, HCl and HNO3 with silicified/carbonated Archaean whole rocks from Barberton Greenstone belt of South Africa. The purpose of this experiment was an identification of the minerals interacting with each reagent and, therefore, a detailed succession of isotopically dated tectonic-thermal episodes recorded in these minerals. The contents of the major, trace and rare-earth elemental, together with the Sr, Nd and Pb isotopic compositions of untreated, leachate and residue triplets allowed identification and analysis of various types of carbonates and sulfates mixed with insoluble silicates. The samples yi…
Determination of U-Pb ages of zircons by direct measurement of the 210Pb/206Pb ratio
1993
Abstract Precise measurements of the 210Pb/206Pb ratio in zircons permits, for the first time, the determination of complete U-Pb ages by measurement of Pb isotopes only, without determination of the U-Pb ratio by isotope dilution. The 238U daughter isotope 210Pb is generally in radioactive equilibrium with 238U; however, the very short half-life of 210Pb (22.3a) results in extremely low 210Pb/206Pb ratios of ∼ 10−8, especially for Archaean zircons. These ratios have been determined using a Finnigan MAT 262® mass spectrometer equipped with a high abundance sensitivity lens system (RPQ). The accuracy of the 210Pb method has been tested on nine different zircon samples with 207Pb/206Pb ages f…
Ylirajainen avioliitto: Puolisovalinta ja avioituminen Suomessa asuvien kurdien keskuudessa
2020
This study examines spousal choice and its gendered dimensions in the Kurdish diaspora, particularly among Kurds resident in Finland. The study focuses on a specific type of marriage migration; transnational marriage, in which migrants marry partners from their families´ homeland or from the same cultural or ethnic background within the diaspora. The research poses the following questions: What transnational courtship and marriages do Kurds resident in Finland enter into? Why do Kurds resident in Finland seek and marry a spouse transnationally? How do individuals and family members engage in negotiations for a suitable partner, in determining the compatibility criteria, and in tackling cult…