Abstract The Ordovician of North and West Africa comprises three main transgressive–regressive sequences understood as ‘second-order’ cycles 10–15 myr duration. Tide- to wave-dominated shallow-marine clastic successions, preserving incidental bryozoan carbonates the north, include fluvial deposits over most proximal southern stretches platform. boundary with Cambrian strata remains unclear but ...

Abstract The Late Ordovician is a paradox, with greenhouse climate shifting to an icehouse during time of presumably high CO2 levels. We used clumped isotope (Δ47) microanalysis fossil brachiopod shells determine paleotemperatures North America (Cincinnati Arch) the Katian (453–443 Ma). Microanalyses brachiopods yielded right-skewed distribution temperatures [T(Δ47)] ranging from 25 °C 55 mode ...

For the first time, an assemblage of cryptospores, which includes 10 species belonging to nine genera, from the Upper Ordovicianstrata, is being reported, in Iran. These cryptospore assemblages were recovered from the upper part of Ghelli Formation., from theeastern Alborz Mountain range. These peri-Gondwanan cryptospores have been classified based on their morphology (monad, truedyad, pseudody...

The Late Ordovician mass extinction (LOME) coincided with dramatic climate changes, but there are numerous ways in which these changes could have driven marine extinctions. We use a palaeobiogeographic database of rhynchonelliform brachiopods to examine the selectivity of Late Ordovician-Early Silurian genus extinctions and evaluate which extinction drivers are best supported by the data. The f...

Taphonomic information is examined to evaluate the early history of connective tissues in the Crinoidea. The pattern of stalk segmentation of Middle and Late Ordovician crinoids is consistent with the two-ligament (intercolumnal and through-going ligaments) pattern present in living isocrinid crinoids and interpreted for fossil isocrinids, holocrinids, and Lower Mississippian crinoids. A single...

This is the first description of Ordovician cephalopods from Morocco. Although their occurrence has been known for a long time, only a poorly preserved conch from the late Katian of Ikhf n’Ouzerg (central Anti-Atlas) was described as “Orthoceras hastile Barrande” by Termier & Termier (1950). In some cases Ordovician cephalopods were mentioned within faunal lists without classification (e.g., Gu...

BACKGROUND Sphaerexochinae is a speciose and widely distributed group of cheirurid trilobites. Their temporal range extends from the earliest Ordovician through the Silurian, and they survived the end Ordovician mass extinction event (the second largest mass extinction in Earth history). Prior to this study, the individual evolutionary relationships within the group had yet to be determined uti...

Establishing the timescale of early land plant evolution is essential for testing hypotheses on the coevolution of land plants and Earth's System. The sparseness of early land plant megafossils and stratigraphic controls on their distribution make the fossil record an unreliable guide, leaving only the molecular clock. However, the application of molecular clock methodology is challenged by the...

The deep time (pre-Quaternary) glacial record is an important means to understand the growth, development, and recession of global cryosphere on very long timescales (10 6 –10 8 Myr). Sedimentological description interpretation outcrops has traditionally played role. Whilst such data remain vital, new insights are now possible thanks freely accessible aerial satellite imagery, widespread availa...