Biodiversity patterns of Early–Middle Ordovician marine microphytoplankton in South China

Review of Palaeobotany and Palynology

Miller³

2015

Section: Agesupporting

confidence: 60%

Section: Comparisonmentioning

confidence: 99%

Late Ordovician to early Silurian acritarchs from the Qusaiba-1 shallow core hole, central Saudi Arabia

Hérissé

Review of Palaeobotany and Palynology

Miller³

2015

“…The first recorded occurrence of the genus there is at the base of the Floian Stage (Yan et al . , ), equivalent to the bases of Stage Slice Fl1 and Time‐Slice 2a (Fig. ).…”

Section: Fads Of Selected Acritarch Morphotypesmentioning

confidence: 99%

First Appearance Datums (FADs) of selected acritarch taxa and correlation between Lower and Middle Ordovician

Servais

et al. 2018

LET

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First Appearance Datums (FADs) of selected, easily recognizable acritarch morphotypes are assessed to determine their potential contribution to correlation between Lower and Middle Ordovician stages and substage divisions along the Gondwanan margin (Perigondwana) and between Perigondwana and other palaeocontinents. The FADs for 19 genera, species and species groups are recorded throughout their biogeographical ranges. The taxa investigated fall into three groups. Some have FADs at about the same level throughout their biogeographical ranges and are useful for long‐distance and intercontinental correlation. Among these are Coryphidium, Dactylofusa velifera, Peteinosphaeridium and Rhopaliophora in the upper Tremadocian Stage; Arbusculidium filamentosum, Aureotesta clathrata simplex and Coryphidium bohemicum in the lower–middle Floian Stage; Dicrodiacrodium in the upper Floian Stage; Frankea in the Dapingian–lower Darriwilian stages; and Orthosphaeridium spp., with FADs in the Dapingian–lower Darriwilian stages of Perigondwanan regions and at about the same level in Baltica. Other taxa, however, have diachronous (or apparently diachronous) FADs, and this needs to be taken into account when using them for correlation. A second group of genera and species, comprising Striatotheca, the Veryhachium lairdii group and the V. trispinosum group, have a recurring pattern of FADs in the Tremadocian Stage on Avalonia and in South Gondwana and West Gondwana, but in the Floian Stage of South China and East Gondwana. The third group, consisting of Arkonia, Ampullula, Barakella, Dasydorus, Liliosphaeridium and Sacculidium, have FADs that are markedly diachronous throughout their biogeographical ranges, although the global FADs of Arkonia, Ampullula, Liliosphaeridium and Sacculidium are apparently in South China and/or East Gondwana. It is possible that diachronous FADs are only apparent and an artefact of sampling. Nevertheless, an alternative interpretation, suggested by recurring patterns, is that some as yet undetermined factor controlled a slower biogeographical spread over time, resulting in diachroneity.

“…In At lower palaeolatitudes on the Gondwanan margin, for example in South China and Argentina, the first occurrence of the Veryhachium lairdii group is apparently in the lowermost Floian or higher ). In South China, the first occurrence of rectangular Veryhachium specimens is in the T. approximatus graptolite Biozone (Yan et al 2011), equivalent to the lower part of Stage Slice Fl1. There is, for example, no record of the Veryhachium lairdii group in late Tremadocian acritarch assemblages from South China (Wang et al 2013).…”

Section: Introductionmentioning

confidence: 99%

The palaeobiogeographical spread of the acritarchVeryhachiumin the Early and Middle Ordovician and its impact on biostratigraphical applications

Servais

et al. 2014

GFF

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