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BIOSTRATIGRAPHIC DATING OF PEBBLES FROM THE UPPER CAMBRIAN CONGLOMERATES IN ESTONIA

1999; Estonian Academy Publishers; Volume: 48; Issue: 3 Linguagem: Inglês

10.3176/geol.1999.3.02

1736-7913

K Mens, I Paalits, I Puura,

Livestock and Poultry Management

Acritarch assemblages were studied in the pebbles from basal conglomerates of the Ulgase and Kallavere formations of northern Estonia.The basal conglomerate of the Ulgase Formation in the Miekalda section, formed during the Olenus time, contained mostly pebbles originating from the Lower Cambrian source rocks, most likely from the Tiskre, Soela, or Vaki formations.The basal conglomerate of the Kallavere Formation in the Pakri Peninsula section, formed slightly before or during the Cordylodus proavus time, contained pebbles with Lower and Upper Cambrian acritarch assemblages.The Upper Cambrian source rocks originate likely from the Ulgase or the Tsitre Formation.Both conglomerates contained rare pebbles with an acritarch assemblage of tentative Middle Cambrian age.The source rock of these pebbles remains disputable, with the Ruhnu and Paala formations, or a missing, completely denudated and reworked part of the Middle Cambrian sequence as hypothetical options.