UPPER CAMBRIAN ACRITARCHS FROM BORING CORE M-72 OF NORTH ESTONIA
1992; Estonian Academy Publishers; Volume: 41; Issue: 1 Linguagem: Inglês
10.3176/geol.1992.1.04
ISSN1736-7913
Autores Tópico(s)Astro and Planetary Science
ResumoUpper Cambrian acritarchs from the borehole M-72, North Estonia, have been described.Six samples from the depth interval 112.8-119.6 m yielded an acri- tarch assemblage which can be tentatively correlated to Parabolina spinulosa and/or Leptoplastus Trilobite Zone.Two new species, Cymatiogalea dentalea sp.n. and C. wiro- nia sp.n., have been described.The present paper is a preliminary account on the acritarchs reco- vered from a part of the so-called "Obolus sandstone" of North Estonia.The material was collected by the author in 1990 from boring core M-72 about 30 km south-east of Tallinn.The assemblage of acritarchs contains well-known Upper Cambrian species as well as some new ones.Material and methods.Six samples were taken from the depth of 112.8 119.6 m (Fig. ).They all, except A-0838, come from very thin brown- coloured organic-rich clay interbeds and contain a rich and-well pre- served assemblage of acritarchs.For maceration HF acid was used; acritarchs were separated with heavy liquid (2.10 g/cm?®) as well as by sieving (mesh diameter 15 ит).; The slides are deposited in the collection of the Geological Museum of Tartu University.-Lithology.The investigated interval of the section overlies the Lower Cambrian Tiskre Formation and underlies the Maardu Member (?Upper Cambrian or Tremadoc) and is represented by grey fine-grained sand- stone with thin (I-3 cm) interbeds of brown organic-rich clay.The sandstone contains abundantly fine debris and complete valves of inar- ticulate brachiopods.By Popov and Khazanovich, this intervalin boring
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