Cephalopods from reef limestone of the Vasalemma Formation, northern Estonia (latest Sandbian, Upper Ordovician) and the establishment of a local warm-water fauna (original) (raw)
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Palaeogeography, Palaeoclimatology, Palaeoecology, 2013
The early Katian (Late Ordovician) was marked by a major greenhouse episode and the early stage of a first-order marine transgression that led to the flooding of much of North America during the middle-late Katian. Multivariate analyses of 33 brachiopod faunas of early Katian (Trentonian, Chatfieldian, late Caradoc) age, including 252 rhynchonelliform genera, demonstrate that the "Trentonian brachiopod faunas" of Laurentia were already clearly differentiated into a Scoto-Appalachian fauna and an epicontinental fauna. Globally, four distinct faunal clusters are identified: Kazakhstan, Avalonia, epicontinental Laurentia, and Scoto-Appalachia. The Scoto-Appalachian fauna, which originated during the Sandbian, persisted into the early Katian and became most closely related to the brachiopod faunas along the western margins of Laurentia. The early Katian epicontinental faunas of Laurentia were more closely related to the coeval brachiopods of the Lithuanian-North Estonian confacies belts of Baltica than to the Scoto-Appalachian fauna. Palaeoecological control on the faunal endemism within Laurentia was attributable to isolation of Appalachian foreland basin by faulting and peripheral bulging during the early Taconic Orogeny, palaeolatitudinal faunal gradient from the subtropical Appalachia to mid-tropical epicontinental Laurentia, as well as different water depth, water temperature, and substrate types between the two palaeogeographical settings of Laurentia.
13th International Symposium on the Ordovician System
2019
west France. In Bohemia and Morocco, chronological equivalent of the Armorican Quartzite do not develop Cruziana-sandstone facies. The Armorican Quartzite is characterised by the widespread presence of trace fossils deposited on a wide shelf in Ibero-Armorica (Gutiérrez-Marco et al., 2017), belonging to the Cruziana and Skolithos ichnofacies, which are representative of various settings in a range of wave-dominated to tide-dominated shallow-marine environments (Gutiérrez-Alonso et al., 2007). Body fossils are rare in the Armorican Quartzite, being most typically associated with concentrations of vertical burrows of Daedalus (= Vexillum, = Humilis), a common ichnogenus in the Skolithos ichnofacies. They represent post-depositional colonisation of storm deposits by wormlike bulldozers, maybe large polychaetes or enteropneusts. These vertical cone-shaped burrows are produced by animals that were opportunistically exploiting recently deposited storm-beds, harvesting for silt-size organic particles or meiofauna living in within the sand interstices (Neto de Carvalho et al., 2016). Such trace fossils are also recorded in the Lower Ordovician of Morocco (as Vexillum), SE France (Montagne Noire) and diverse places in North Africa, Middle East and the Arabian Peninsula (Seilacher, 2000). Trace fossils such as Cruziana and Daedalus (identified as Heimdallia but this genus is a junior synonym of Daedalus (see Fillion & Pickerill, 1990)) are recorded in what is regarded as an extension of the Armorican Quartzite facies in eastern Newfoundland, as well as large-sized Lingulobolus species (over 30 mm long; see Walcott, 1912) from Lance Cove, Bell Island, Newfoundland (Bell Island Group, upper Tremadocian, Lower Ordovician). The brachiopod faunas are developed either as rare but extensive linguliform beds formed by centimetric to decimetric accumulation of highly fragmented taxa, usually difficult to identify (Emig & Gutiérrez-Marco, 1997), or by complete specimens (even including conjoined valves) preserved at the base of those storm sandstone sequences colonised by Daedalus (see Fig. 1.5). The faunas consist of low diversity assemblages (sometimes monotaxic) of 'giant' linguliform brachiopods including Ectenoglossa lesueuri (Rouault) (Fig. 1.4), Lingulobolus brimonti (Rouault), L. hawkei (Rouault), Lingulepis crassipyxis Havlíček (see Lingulepis sp. on Fig. 1.2), Tomasina criei (Davidson), Pseudobolus? salteri (Davidson), and a new bizarre 'giant' linguliform taxon (see Figs 1.1, 1.3) recognised so far in the Armorican Quartzite of northern Portugal only (Sá 2005). The brachiopods found in the Armorican Quartzite in France and Iberia were described and identified in works published since the middle of the 19 th Century, a.o. by Rouault (1850) [later revised by Davidson (1880)], Guillier (1881), and Coke & Gutiérrez-Marco (2001). Cocks & Lockley (1981) reassessed the brachiopod fauna described by Salter (1864) from the Budleigh Salterton Pebble Bed. The distinctive elongated spatulate glosselline Ectenoglossa lesueuri is present in the Armorican Quartzite in England,
The Ordovician Clitambonitidine Brachiopod Genus Vellamo in Estonia
Proceedings of the Estonian Academy of Sciences. Geology, 1998
Vellamo Opik, 1930 is a cosmopolitan Ordovician brachiopod genus originating from the epicontinental seas of the Baltoscandian Palaeobasin. As a result of the systematic revision of the Estonian material, 16 Vellamo species are described or discussed. The morphological characters of taxa are presented. Special attention is paid to the ontogenetical changes in the shell morphology, as the earliest growth stages are closely similar in all species of the genus. On the basis of the stratigraphical distribution three successive stages in the development of the Estonian species are distinguished.
Diversification patterns in the clitambonitoid brachiopods of the Ordovician of Baltoscandia
Bulletin of the Geological Society of Denmark
Two intervals of clitambonitoid diversification followed by major extinctions have been recorded in the Ordovician rocks of Baltoscandia, one during the Arenig and a second in the mid Caradoc. The Arenig radiation was characterized by high origination and extinction rates of both genera and species associated with the development of carbonate environments across the region. In addition the migration of numerous stocks of clitambonitoids out of Baltica to a number of other palaeocontinents occurred during this diversity peak during the Arenig, together with the spread of the majority of genera into a range of more local environments. A marked extinction in the Early Llanvirn coincided with shifts in sedimentation patterns whereas the diversity hike in the Mid Caradoc reflects the diversification of clitambonitoid species in both inner and outer shelf environments. The later Caradoc extinction coincided with an extensive eustatic regression event and the major restructuring of the eco...
Chapter 10 Biogeography of Ordovician linguliform and craniiform brachiopods
Geological Society, London, Memoirs, 2013
The biogeographical patterns shown by Ordovician linguliform and craniiform brachiopods are greatly influenced by their dominance in low-diversity associations in marginal environments. This is particularly evident in the Early Ordovician, when linguliform-dominated dysaerobic assemblages are widely distributed along the deep shelves of Gondwana, the Kazakhstanian terranes and in Baltica. By the Darriwilian, micromorphic linguliforms are characteristic components of the pantropical climatic-controlled faunas of Laurentia, Cuyania and Kazakhstanian terranes, which-in spite of separation by extensive oceans-retain a distinct similarity. Analysis of craniiform biogeographical distribution is impeded significantly by the poor state of craniide taxonomy and lack of reliable data from most regions. However, in general their biogeographical dispersion is similar to other groups of the Palaeozoic Evolutionary Fauna. Unlike the linguliforms, which are important members of the Cambrian Evolutionary Fauna, there is no convincing Cambrian craniiform record; they may have evolved and dispersed from Gondwana and associated microcontinents and island arcs. The earliest well-established record is from the late Tremadocian of temperate to high-latitude peri-Gondwana. During most of the Ordovician, they have a peri-Iapetus distribution. They are very rare or absent in tropical Gondwana, South China and Kazakhstanian terranes and are not yet documented from Siberia. The trimerellides probably evolved in tropical peri-Gondwanan island arc settings. Their dispersion and major features of biogeography mirror those of atrypides. Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.
Evolution of Laurentian brachiopod faunas during the Ordovician Phanerozoic sea level maximum
Earth-Science Reviews, 2015
The distribution of brachiopod faunas around Laurentia during the Ordovician period was influenced by the dynamicity of the surrounding palaeo-continents. Laurentia seemed to have been somewhat static, straddling the palaeo-equator, whereas the late Ordovician was characterised by the later stages of the closure of the Iapetus Ocean, with Baltica, eastern Avalonia and a variety of exotic terranes docking the southern and south-eastern coasts of Laurentia. In the earliest Ordovician, ‘primitive’ taxa that originated in the Cambrian were major components of brachiopod faunas. Later in the early Ordovician some major, first appearances (plectambonitoids) contributed to increase the diversity of the faunas, and by the end of the middle Ordovician, a very diverse fauna had conquered the continent: strophomenoids first appeared, plectambonitoids increased importance, and overall rhynchonelliform diversity exploded. During the tectonically active Ordovician, orogenies created geographical barriers that accentuated the faunal differences between peri-Laurentian terranes and cratonic assemblages. The late Ordovician diversification of brachiopods is the result of several gradual events spanning the Dapingian to the Sandbian. From the Sandbian to the Katian, the Scoto-Appalachian fauna, which is characteristic of terranes in the vicinity of the south-eastern margin of Laurentia, retained its peculiarity and did not invade the epicontinental seas of Laurentia. By the Hirnantian, two main groups, characterised by well-defined climatically controlled provinces, can be differentiated. Although the Hirnantian was marked by drastic extinction events, part of Laurentia (notably the intracratonic platform) may be identified as a place of hospitality for brachiopod faunas as many taxa thrived across the extinction boundary, into the Silurian period. Keywords Biodiversification; Brachiopoda; Distribution; Laurentia; Ordovician; Palaeobiogeography
2004
Analysis of Orthida (Brachiopoda) spatio-temporal data from a new database indicates that five major developments controlled the faunal provincialism of the Orthida in the Greater Iapetus Ocean during the Ordovician-Silurian. These developments include: 1) A diversification during the Early Ordovician; 2) a diversity reduction during the Middle Ordovician, followed by; 3) renewed diversification during the early Caradoc; 4) the Hirnantian glaciation; and 5) a gradual homogenization of the faunas during the Silurian, despite some increasing endemism. The orthides of the peri-Gondwanan European massifs may have formed a faunal association, distinct from the faunas of the Iapetan central area, whereas the general pattern of faunal associations appears to be related to palaeolatitude and the relative positions of the palaeoplates. The observed faunal patterns generally support recent plate tectonic reconstructions.
Abstract Background: We examine the environmental, climatic and geographical controls on tropical ostracod distribution in the marine Ordovician of North America. Methodology/Principal Findings: Analysis of the inter-regional distribution patterns of Ordovician Laurentian ostracods, focussing particularly on the diverse Late Ordovician Sandbian (ca 461 to 456 Ma) faunas, demonstrates strong endemicity at the species-level. Local endemism is very pronounced, ranging from 25% (e.g. Foxe basin) to 75% (e.g. Michigan basin) in each basin, a pattern that is also reflected in other benthic faunas such as brachiopods. Multivariate (ordination) analyses of the ostracod faunas allow demarcation of a Midcontinent Province and a southern Marginal Province in Laurentia. While these are most clearly differentiated at the stratigraphical level of the bicornis graptolite biozone, analyses of the entire dataset suggest that these provinces remain distinct throughout the Sandbian interval. Differences in species composition between the provinces appear to have been controlled by changes in physical parameters (e.g. temperature and salinity) related to water depth and latitude and a possible regional geographic barrier, and these differences persist into the Katian and possibly the Hirnantian. Local environmental parameters, perhaps operating at the microhabitat scale, may have been significant in driving local speciation events from ancestor species in each region. Conclusions/Significance: Our work establishes a refined methodology for assessing marine benthic arthropod microbenthos provinciality for the Early Palaeozoic.
The Brachiopod Succession Through the Silurian—Devonian Boundary Beds at Dnistrove, Podolia, Ukraine
Acta Palaeontologica Polonica, 2012
In the classic section across the Silurian-Devonian boundary at Dnistrove (Podolia, Ukraine) the brachiopod fauna has never been studied in detail. This paper presents results of research on brachiopods from this important locality and time interval. Bed−by−bed collecting has enabled the detailed distribution of brachiopod taxa through the boundary beds to be revealed. Generally, the reference section at Dnistrove yields rather scarce but often well preserved brachiopods. Dayia bohemica and Dnestrina gutta can be regarded as characteristic species for the uppermost Silurian. A relatively high−di− versity but low−abundance brachiopod fauna occurs in the lowest 1.8 m of the earliest Devonian. Only three forms have been found to cross the Silurian-Devonian boundary: the strophomenide Plectodonta (Plectodonta) mariae pantherae subsp. nov., the atrypide Gracianella (Sublepida) paulula sp. nov., and the spiriferide Howellella (Howellella) latisi− nuata. A relatively narrow brachiopod−rich interval at 5.5 m above the Silurian-Devonian boundary yields 16 brachiopod species which probably indicate a setting near the lower limit of the photic zone equivalent to the Benthic Assemblage 3-4 boundary. Two new species and one new subspecies are described: Skenidioides tatyanae, Plectodonta (Plectodonta) mariae pantherae, and Gracianella (Sublepida) paulula.