Devonian Deposits and Fossils of the Ketleri Formation, Varkaļi Member

Barinova Tatjana, 2007. Devona Ketleru svītas Varkaļu ridas nogulumi un fosilijas. Bakalaura darbs. Latvijas Universitāte, Rīga. Bakalaura darbs ir veltīts Latvijas augšējā devona Famenas stāva Ketleru svītas augšējās, Varkaļu ridas nogulumu un fosiliju izpētei, kura tika veikta atsegumos Ventas krastā pie Ketleriem. Darbā ir apskatīti jautājumi par ridas nogulumu sastāvu, uzbūvi un sedimentācijas apstākļiem, ridas iežos sastopamo fosiliju sastāvu, izplatību un apglabāšanās apstākļiem. Darbā ir iekļauti atsegumu, makro- un mikrofosiliju fotogrāfijas, nogulumu ģeoloģiskie griezumi, slīpo slānīšu kritumu diagrammas, iežu paraugu granulometriskās analīzes dati un fosiliju tafonomiskās analīzes dati. Ridu pārsvarā veido smalkgraudaini kopumā labi šķiroti irdeni smilšakmeņi ar nelielu aleirīta un vidējgraudainās smilts piejaukumu dažos slāņos, bieži ar vizlu un nelielā daudzumā - māla oļiem un plāksnītēm. Smilšakmeņiem raksturīga slipslāņota, retāk – masīva tekstūra, tie veidojušies vienvirziena straumēs ar dominējošo dienvidu virzienu. Makrofosīlijas sastopamas sporādiski, turpretī mikrofosīlijas atrastas gandrīz visos slāņos; ir konstatēta atkarība starp smilšaino nogulumu granulometrisko sastāvu un mikrofosiliju daudzumu tajos. Pirmo reizi Varkaļu ridas nogulumos ir atrastas Acanthodes tipa zvīņas. Atslēgas vārdi: Latvija, Kurzeme, Famenas stāvs, devona mugurkaulnieki, tetrapodiBarinova Tatjana, 2007. Devonian Deposits and Fossils of the Ketleri Formation, Varkaļi Member. Bachelor thesis. University of Latvia, Rīga. The bachelor paper is dedicated to the examination of sedimentary rocks and fossils belonging to the upper Famennian (Upper Devonian) Varkaļi Member of the Ketleri Formation. The research took place in the outcrops on the right bank of the River Venta close to the farmhouse “Ketleri”. The paper covers the problems of composition, structure and sedimentary environment of the Varkaļi Member, as well as of composition and distribution of fossils and peculiarities of their burial. The given work contains the photographs of the outcrops, macro and microfossils, geological sections of rocks, azimuthal orientation of the cross-bedding as well as data concerning grain-size analysis of the rock samples and taphonomical peculiarities of the burial of the vertebrate remains. The Varkaļi Member consists mainly of the fine- and very fine-grained well-sorted weakly cemented sandstone with small amount of silt and medium grained sand, often with mica and rarely with clay pebbles and plates. The cross-stratification is characteristic, sometimes sandstone is massive; sandstone is formed under the dominant currents directed to south. Macrofossils are distributed sporadically, whereas microfossils have been found almost in each layer; the amount of microfossils is related to the grain-size composition of rock. Acanthodes-type scales have been found in the Varkaļi Member for the first time. Key-words: Latvia, Kurzeme, Famennian, Devonian vertebrates, tetrapod