The Great Ordovician Biodiversification Event (GOBE): definition, concept and duration

Abstract

The Ordovician biodiversification has been recognized since the 1960s; the term ‘The Great Ordovician Biodiversification Event’, abbreviated by many as the ‘GOBE’, has been used for the past 20 years. The conceptual development and terminology applied to this crucial episode in marine life signify its considerable complexity. The GOBE includes successive biodiversity phases of the pelagic and benthic biotas, possibly decoupled. Put simply, the GOBE can be seen as a sequence of diversifications of the planktonic (late Cambrian–Early Ordovician), level‐bottom benthic (Early–Middle Ordovician) and reef communities (Middle–Late Ordovician), although the boundaries of these ‘events’ are diachronous (as for the entire GOBE), and it is logical to assume that these communities co‐evolved and interacted. The GOBE also includes several Biotic Immigration Events (BIMEs), such as the ‘Richmondian Invasion’ and the ‘Boda Event’, recording the large‐scale dispersal of taxa from one biogeographical area to another. The GOBE is thus the sum of the diversity trends of all individual fossil groups showing rapid increases, diachronously, during different intervals and across different regions. It thus spans the entire Ordovician, capturing the increasing total diversity of marine organisms during the period. The GOBE is not simply one, but many sequential events.

Lower–Middle Ordovician carbon and oxygen isotope chemostratigraphy at Hällekis, Sweden: implications for regional to global correlation and palaeoenvironmental development

“…; Algeo et al . ; Edwards & Saltzman ; Servais & Harper ). By contrast, the last portion of the Ordovician Period is marked by the first of the big five mass‐extinction events, during which approximately 85% of all marine species are estimated to have disappeared (Jablonski ; Sheehan ; Harper et al .…”

Dating of sedimentary rock intervals using visual comparison of carbon isotope records: a comment on the recent paper by Bergström et al . concerning the age of the Winneshiek Shale

“…(), in which it was argued that there is a causal link between an enhanced meteorite influx and the so‐called Great Ordovician Biodiversification Event (GOBE; e.g., Webby et al . ; Servais & Harper ) during the Middle Ordovician (cf. Rasmussen et al .…”

The Sirius Passet Lagerstätte of North Greenland: a remote window on the Cambrian Explosion

“…New discoveries from the Sirius Passet Lagerstätte have not only increased the diversity of early Cambrian faunas, but the excellence of preservation, despite some metamorphism and tectonism, has presented new information on the gut contents of a number of euarthropods and lobopods, supporting predatory and/or scavenging life modes (Strang et al 2016a;Peel 2017c), as well as on their visual and nervous systems (Park et al 2018) together with muscle fibres (Budd 2011;Peel 2017c). This distinctive ecosystem structure emphasizes the contrast between the Cambrian and Paleozoic evolutionary faunas, the latter dominated by a suspension-feeding benthos generated during the Great Ordovician Biodiversification Event (Harper 2006;Servais et al 2010;Servais & Harper 2018). The early Cambrian assemblages display a high degree of endemism (Meert & Lieberman 2008;Peng et al 2012) that changed only later in the Cambrian with the more widespread distribution of nonarticulate brachiopods (Bassett et al 2002) and more complex and diverse distributional patterns in the trilobites (Álvaro et al 2013).…”