Devona Šķerveļa svītas Gobdziņu ridas nogulumi un to veidošanās apstākļi
Date
2008
Authors
Ābele, Helvis
Journal Title
Journal ISSN
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Publisher
Latvijas Universitāte
Abstract
Bakalaura darbā ir detalizēti raksturoti devona Šķerveļa svītas Gobdziņu ridas nogulumi un to veidošanās apstākļi. Apkopoti citu pētnieku iepriekš iegūtie dati par Gobdziņu ridas nogulumiem Latvijā, sastādīts un aprakstīts Gobdziņu ridas ģeoloģiskais griezums Ātrā kalna atsegumā, no katra izdalītā slāņa noņemti iežu paraugi, kuriem veikta granulometriskā analīze, izgatavoti un aprakstīti plānslīpējumi, kā arī veikta mikrofosīliju analīze.
Pētījumu rezultātā tika noskaidrots, ka sākotnēji Gobdziņu ridas nogulumi ir veidojušies ūdens vidē, bet to pēcsedimentācijas izmaiņas acīmredzot ir notikušas subaerālajos apstākļos tuksnešiem līdzīgos apstākļos, par ko liecina dolomīta garoziņas ap drupu graudiem, šūnveida tekstūras, dolomītu garozas, iespējamie pizolīti un koncentriskie dolomīta veidojumi, kā arī griezuma vidusdaļā konstatētās iespējamā paleokarsta pazīmes.
Atslēgvārdi: Famenas stāvs, subaerālie apstākļi, dolomīta garozas, paleokarsts
Helvis Ābele, 2008. Deposits and sedimentary environment of the Gobdziņi Member, Šķervelis Formation, Devonian. Bachelor thesis. Deposits and sedimentary environment of the Gobdziņi Member, Šķervelis Formation, Devonian, have been characterised in details in the Bachelor thesis. The results of previous studies of the Gobdzini Member deposits belonging to the Šķervelis Formation from Latvia have been summarized; geological section of the Ātrais kalns outcrop is prepared and described, rock samples collected from each layer were processed to perform grain-size and microfossil analysis, as well as studied in thin-sections. Interpretation of the results suggest that the Gobdziņi Member deposits have formed in shallow water environment, but were altered in subaerial conditions resembling desert, testified by dolomite incrustation around grains, cellular textures, and dolomite crust, possible pisoids and concentric dolomite aggregates, as well as possible paleokarst indications in the middle part of the section. Keywords: Famennian, subaerial conditions, dolomite crust, paleokarst
Helvis Ābele, 2008. Deposits and sedimentary environment of the Gobdziņi Member, Šķervelis Formation, Devonian. Bachelor thesis. Deposits and sedimentary environment of the Gobdziņi Member, Šķervelis Formation, Devonian, have been characterised in details in the Bachelor thesis. The results of previous studies of the Gobdzini Member deposits belonging to the Šķervelis Formation from Latvia have been summarized; geological section of the Ātrais kalns outcrop is prepared and described, rock samples collected from each layer were processed to perform grain-size and microfossil analysis, as well as studied in thin-sections. Interpretation of the results suggest that the Gobdziņi Member deposits have formed in shallow water environment, but were altered in subaerial conditions resembling desert, testified by dolomite incrustation around grains, cellular textures, and dolomite crust, possible pisoids and concentric dolomite aggregates, as well as possible paleokarst indications in the middle part of the section. Keywords: Famennian, subaerial conditions, dolomite crust, paleokarst
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