Palynology and micropaleontology of the clam bank formation (Lower Devonian) of Western Newfoundland, Canada

Abstract

Sandstone and siltstone samples collected from the lowest part of the Clam Bank Formation in western Newfoundland contain a distinctive monospecific conodont assemblage of Ozarkodina remscheidensis eosteinhornensis and O. remscheidensis ssp., confidently dated as Late Ludlow through Lochkovian. Palynomorph assemblages of terrestrial spores, acritarchs, chitinozoans, scolecodonts and plant fragments are relatively abundant and diverse in the lower 250 m of this formation. Taxa include the cryptospore genera Cymbohilates, Acontotetras, Hispanaediscus, Laevolancis, and Tetrahedraletes, spore genera Ambitisporites, Aneurospora, Apiculiretusispora, Emphanisporites, Retusotriletes, Synorisporites, Vermiverruspora, and a new species Stellatispora fahraeusi. Acritarchs include the taxon Triangulina sanpetrensis and chitinozoa include Angochitina chlupaci. Palynomorphs indicate a Lochkovian age, corresponding with the Apiculiretusispora sp. E zone from Europe. In well preserved samples from this section, the fossil terrestrial palynomorph assemblages from these shallow marine deposits correspond closely in species diversity and concentration with values reported for modern shelf deposits located adjacent to low Arctic moss and sedge tundra. By inference, earliest Devonian terrestrial vegetation must have been relatively well developed on this ancient coastline.