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- Title
VIDURIO LIETUVOS TEKTONINĖS ZONOS TĘSINYS ŠV LIETUVOS KRISTALINIAME PAMATE: CHEMINIAI IR IZOTOPINIAI TYRIMAI.
- Authors
Šiliauskas, Laurynas; Skridlaitė, Gražina; Whitehouse, Martin; Putnaitė, Jolanta
- Abstract
The crystalline basement of Lithuania in the western East European Craton (EEC) is covered by 200-1000 m thick Phanerozoic sediments and known only though drillings and geophysics. Reconstruction of different igneous belts is based mainly on chemical and isotopic studies. The Mid-Lithuanian domain (MLD) of 1.86-1.84 Ga is shown by Bogdanova et al. (2015) to extend from southern through middle Lithuania to its northwest. However, the rocks in western and southern parts of the country have been exposed to different-grade metamorphism that has altered their primary composition. In order to track the Mid-Lithuanian domain (MLD) continuation to the west, zircons from two samples of metamorphosed igneous rocks (St87/1158.5 and Vd62/1665) were dated at the NORDSIM facility and Sm-Nd and Rb-Sr isotopes from the six MLD samples (268/436.3, 346/563.4, 347/342.8, 62/1665, 26/1763, 99/1218.3) were investigated at the Swedish Museum of Natural History in Stockholm. Both dated samples have formed in a subduction-related tectonic setting. They, however, differ in REE patterns (chondrite-normalised), the St87 having a flatter slope and being less fractionated than the Vd62. Both rocks have yielded similar U-Pb ages: Vd62 of 1849 ± 8 Ma and St87 of 1843 ± 9 Ma. Rocks of similar age and chemical composition have been recognized in the surrounding area and to the south. According to Bogdanova et al. (2015) they can be correlated with the similar-aged complexes in south-central Sweden. The recent geochemical and isotopic study of the rocks not only confirmed the extension of the MLD to northwest, but also revealed the heterogeneities of the melt-generation source along a former subduction zone and its possible continuation from the south to the west.
- Subjects
LITHUANIA; GEOLOGICAL time scales; IGNEOUS rocks; SUBDUCTION zones; GEOPHYSICS; NATURAL history museums; SUBDUCTION; AMALGAMATION
- Publication
Geologija. Geografija, 2018, Vol 4, Issue 4, p195
- ISSN
2351-7549
- Publication type
Article