acritarch


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acritarch

[′ak·rə‚tark]
(paleontology)
A unicellular microfossil of unknown or uncertain biological origin that occurs abundantly in strata from the Precambrian and Paleozoic.
References in periodicals archive ?
present the discovery of the messaoudensis-trifidum acritarch assemblage in the upper Tremadocian-lower Floian, Lower Ordovician of Morocco.
An acritarch assemblage sampled from the North Alton Formation indicates a Jiangshanian (mid-Furongian) age (White et al.
There are many techniques for shale maturation measurement, but the simplest and easiest is certainly the popular Conodont Alteration Index (CAI) that can also be used with acritarch organic material.
The researchers found 30 acritarch species, 13 of which had never been seen before.
The acritarch record of Australia indicates that pre- and post-Snowball populations are identical and do not indicate repopulation of marine areas by extremophiles that survived both catastrophic glaciation in hot springs and the brutal greenhouse conditions which followed (Grey et al.
The messaoudensis-trifidum acritarch assemblage is known from upper Tremadocian to lower Floian (Lower Ordovician) strata in many localities on the Gondwanan margin (Servais et al.
1990; Mens & Pirrus 1997) and possibly to the Asteridium tornatum-Comasphaeridium velvetum acritarch Zone (Moczydlowska 1991).
The conodont faunas from this area have been studied intensively and David Gelsthorpe (University of Leicester, UK) is currently engaged in a detailed study of acritarch diversity changes through the Ireviken Event in NW Gotland.
The outcrops also contain undescribed pre-Agnostus pisiformis acritarch assemblages that confirm the timing of their deposition to the Cambrian Epoch 3 (Palacios et al.
The age of the Kotlin sandstone is rather loosely constrained (< 570 Ma), whereas the Lontova Formation is represented by the sub-trilobitic acritarch assemblage of Asteridium tornatum-C.