| Abstract [eng] |
(Diploma work of magistracy) Rasa Smolskutė Department of Geology and Mineralogy, Faculty of Natural Sciences, Vilnius University Doc. Algirdas Brazauskas Research adviser of diploma Summary The main purpose of the work is to point out the regularities of rock sedimentation in Minija regional stage in Lithuania. 59 cores that bored through Minija regional stage of Silurian were analysed. According to available paleontological, litological and geophysical data stratigraphical ambit of all analysed elements has been revised in every core. Successive layer correlation has been completed and their rock formation peculiarities, and sedimentation cycles of Minija regional stage were defined. According to regular sediment accumulation cycles 4 separate sedimentation environments were pointed out in analysed stratigraphic unit. They are distributed in following order: Southwest and West Lithuania, Middle and periphery of West Lithuania, Middle and East Lithuania. In Southwest and West Lithuania during Minija regional stage sedimentation of lower than wave basis environment prevailed and greyish clay material without clear lamination accumulated. In west periphery of Middle Lithuania well-aerated storm sedimentation environment prevailed and rocks with clear laminated grey clayish microcrystalline limestone and green-grey marl accumulation occurred. In Middle Lithuania during clear storm sedimentation environment less clayish limestone, often with detritus, accumulated. Further in the east only shallow-water sedimentation environment formed and was poorly aerated, stagnant lagoon with average salinity. Grey clayish limestone with detritus and interlayers of grey and even black dolomite marl formation with rich detritus took place here. In the very east – during lagoon sedimentation environment with increased salinity dolostones and marls were formed. |
