Cambrian radiation

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  • THE CAMBRIAN RADIATION, which commenced around 550 million years ago, arguably ranks as the single most important episode in the development of Earth’s marine biota. Diverse benthic communities with complex tiering, trophic webs, and niche partitioning, together with an elaborate pelagic realm, were established soon after the beginning of the Cambrian period. This key event in the history of life changed the marine biosphere and its associated sediments forever.

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  • CHAPTER SEVEN The Cambrian Radiation and the Diversification of Sedimentary Fabrics The Cambrian represents a pivotal point in the history of marine sedimentary rocks. Cambrian biofabrics that are directly a product of metazoans include ichnofabrics, shell beds, and constructional frameworks.

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  • CHAPTER TWO Recent revisions to the early Paleozoic time scale have been used to recalibrate ages assigned to stratigraphically dated paleomagnetic poles of that era. In particular, a value of 545 Ma has been used for the base of the Cambrian. Selected poles have then been used to derive apparent polar.

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  • CHAPTER SIX Australian Early and Middle Cambrian Sequence Biostratigraphy with Implications for Species Diversity and Correlation This description of Lower and Middle Cambrian strata from the Stansbury, Arrowie, Amadeus, and Georgina basins combines elements of biostratigraphy and sequence stratigraphy.

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  • CHAPTER NINE Ecology and Evolution of Cambrian Plankton Probable eukaryotic phytoplankton first appear in the fossil record in the Paleoproterozoic but undergo almost no morphologic change until the Early Cambrian. The radiation of diverse acanthomorphic phytoplankton in exact parallel with the Cambrian explosion of large animals.

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  • CHAPTER TWELVE Ecology and Evolution of Cambrian Reefs The history of reef building through the Cambrian records the replacement of predominantly microbial communities by those in which sessile animals participated in construction, so heralding a new reef ecosystem with elaborate trophic webs, complex organism interactions

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  • CHAPTER FIFTEEN Molluskan diversification was a result of the adaptation of skeletonized forms to various habitats. The ecologic radiation of Cambrian skeletonized mollusks and their possible relatives led to the appearance of all trophic groups, many of them during the Cambrian: deposit feeders.

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  • CHAPTER SEVENTEEN Ecologic Evolution of Cambrian Trilobites Skeletonized Cambrian trilobites are both varied and abundant and provide potential proxies for understanding the evolution of nonskeletonized arthropod groups. Soft- and hard-part morphology suggests that Cambrian Trilobita.

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  • CHAPTER EIGHTEEN Ecology of Nontrilobite Arthropods and Lobopods in the Cambrian Arthropods and lobopods first appear for certain in the body fossil record in the Atdabanian and, at the time of this appearance, already exhibit a wide spread of ecologic strategies.

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  • CHAPTER NINETEEN Ecologic Radiation of Cambro-Ordovician Echinoderms Echinoderms represent a modest component of the initial metazoan radiation during the Cambrian but responded to global environmental changes across the CambroOrdovician boundary with rapid and prolific diversification to more varied lifestyles.

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  • CHAPTER TWENTY Calcified Algae and Bacteria Calcified microbes expanded rapidly in abundance and diversity from NemakitDaldynian to Tommotian. This rapid diversification near the base of the Cambrian reflects a burst of cyanobacterial evolution, and commencement of an environmentally facilitated Cyanobacterial.

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  • CHAPTER THREE Global paleogeographic world maps compiled for the late Vendian, Cambrian, and Early to Middle Ordovician bring together, possibly for the first time, a systematic and uniform overview of paleogeographic and facies distribution patterns for this interval.

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  • CHAPTER FOUR A global overview of sediment patterns and accumulation rates, and carbon, strontium, and neodymium isotopes confirms that increasing rates of subsidence and uplift accompanied the dramatic radiation of animal life through the NeoproterozoicCambrian interval.

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  • CHAPTER FIVE Climate Change at the Neoproterozoic-Cambrian Transition Varangerian and lower Sinian glacial deposits are found in Argentina, Uruguay, Mato Grosso (Brazil), Namibia, Laurentia, and probably southern Brazil, which were all situated close together during Neoproterozoic-Cambrian times.

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  • CHAPTER TEN Evolution of Shallow-Water Level-Bottom Communities Features of Cambrian level-bottom communities that inhabited carbonate and siliciclastic substrates are outlined. A high diversity of level-bottom communities with multiple trophic guilds was established in the Early Cambrian.

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  • CHAPTER ELEVEN Evolution of the Hardground Community Hardground communities first appeared in the late Middle Cambrian but they were not common before the Ordovician. Two factors had a major influence on the early development of hardgrounds and resulted in abrupt and rapid increase in hardground area.

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  • CHAPTER SIXTEEN Brachiopods All brachiopods are sessile benthic organisms; in feeding style they are ciliary suspension feeders. Cambrian brachiopods show several types of substrate relationships: pedicle-anchoring, free-lying, cemented epifaunal, infaunal.

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  • CHAPTER EIGHT Biotic Diversity and Structure During the Neoproterozoic-Ordovician Transition Diversity of 4,122 metazoan genera, 31 calcimicrobial genera, and 470 acritarch species are plotted for the Nemakit-Daldynian– early Tremadoc interval at zonal level.

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  • CHAPTER THIRTEEN Evolution of the Deep-Water Benthic Community Megascopic life evolved in the Archean with the buildup of stromatolitic mounds in shallow-water environments. By the Proterozoic, stromatolites had already extended down to well below fair-weather wave base.

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  • CHAPTER ONE Introduction arguably ranks as the single most important episode in the development of Earth’s marine biota. Diverse benthic communities with complex tiering, trophic webs, and niche partitioning, together with an elaborate pelagic realm.

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