Taphonomy of Exceptionally Perserved Fossils from the Kinzers Formation (Cambrian), Southeastern Pennsylvania PDF Download
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Author: Ethan S. Skinner
Publisher:
ISBN:
Category : Paleontology
Languages : en
Pages :
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Book Description
Abstract: The pelitic Emigsville Member of the Kinzers Formation (Cambrian), southeastern Pennsylvania, is a deposit of exceptional fossil preservation. It contains three main lithofacies that were part of a mixed siliciclastic-carbonate debris fan developed seaward of a carbonate shelf along the Appalachian margin of Laurentia. Fossils were exceptionally preserved in a shelf environment subject to tempestite deposition. Most remains are fragmentary, which emphasizes the importance of predation as a taphonomic process where Emigsville sediments were deposited. Remains are preserved mostly as organic carbon films, pyrite crusts, and aluminosilicate films. These preservation styles apparently depended upon the development of microbial consortia; some microbes were autolithifiers. Sedimentary and biological evidence suggests that anoxia, salinity fluctuations, and sedimentary obrution played relatively minor roles for fossil preservation in the Emigsville Member of the Kinzers Formation. The abundance of exceptionally preserved remains suggests that unusual sedimentary conditions were not necessary in the Cambrian in order for exceptional preservation to occur. The abundance of predation evidence in a deposit of exceptional preservation reinforces the concept that predation was the primary taphonomic filter during Cambrian time.
Author: Ethan S. Skinner
Publisher:
ISBN:
Category : Paleontology
Languages : en
Pages :
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Book Description
Abstract: The pelitic Emigsville Member of the Kinzers Formation (Cambrian), southeastern Pennsylvania, is a deposit of exceptional fossil preservation. It contains three main lithofacies that were part of a mixed siliciclastic-carbonate debris fan developed seaward of a carbonate shelf along the Appalachian margin of Laurentia. Fossils were exceptionally preserved in a shelf environment subject to tempestite deposition. Most remains are fragmentary, which emphasizes the importance of predation as a taphonomic process where Emigsville sediments were deposited. Remains are preserved mostly as organic carbon films, pyrite crusts, and aluminosilicate films. These preservation styles apparently depended upon the development of microbial consortia; some microbes were autolithifiers. Sedimentary and biological evidence suggests that anoxia, salinity fluctuations, and sedimentary obrution played relatively minor roles for fossil preservation in the Emigsville Member of the Kinzers Formation. The abundance of exceptionally preserved remains suggests that unusual sedimentary conditions were not necessary in the Cambrian in order for exceptional preservation to occur. The abundance of predation evidence in a deposit of exceptional preservation reinforces the concept that predation was the primary taphonomic filter during Cambrian time.
Author: L.E. Babcock
Publisher: Gulf Professional Publishing
ISBN: 9780444520654
Category : Science
Languages : en
Pages : 240
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Book Description
The Neoproterozoic-Cambrian transition was a time of fundamental change in the biosphere. Between about 570 and 510 million years ago, marine organisms underwent considerable evolutionary innovation during a time of shifting ecological setting. This dramatic activity culminated in the first stratigraphic appearances of many recognizable groups of animals, an "event" often referred to as the "Cambrian explosion". In addition, there was a major change from a microbial mat-dominated sediment-water interface to a more extensively burrowed interface in shallow-marine settings. The early fossil record is a function not only of the rise or ecological diversification of marine organisms, but also the development of taphonomic and sedimentary conditions suitable for the preservation of mineralizing and nonmineralizing organisms. This book is devoted to an exploration of some of the emerging concepts and techniques used to develop greater insight into the early record of biologic diversification and the preservational record of that diversification during the Neoproterozoic-Cambrian transition. * Addresses key issues related to the Cambrian diversification of multicellular animals * Provocative new ideas about the factors involved in the exceptional preservation of fossils, with a balance between the development of ideas and hypothesis testing * Broad coverage of topics related to the Cambrian diversification of animals and the fossil record of that diversification; broad geographic coverage
Author: D.A.T. Harper
Publisher: Geological Society of London
ISBN: 1862393737
Category : Science
Languages : en
Pages : 485
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Book Description
The Early Palaeozoic was a critical interval in the evolution of marine life on our planet. Through a window of some 120 million years, the Cambrian Explosion, Great Ordovician Biodiversification Event, End Ordovician Extinction and the subsequent Silurian Recovery established a steep trajectory of increasing marine biodiversity that started in the Late Proterozoic and continued into the Devonian. Biogeography is a key property of virtually all organisms; their distributional ranges, mapped out on a mosaic of changing palaeogeography, have played important roles in modulating the diversity and evolution of marine life. This Memoir first introduces the content, some of the concepts involved in describing and interpreting palaeobiogeography, and the changing Early Palaeozoic geography is illustrated through a series of time slices. The subsequent 26 chapters, compiled by some 130 authors from over 20 countries, describe and analyse distributional and in many cases diversity data for all the major biotic groups plotted on current palaeogeographic maps. Nearly a quarter of a century after the publication of the ‘Green Book’ (Geological Society, London, Memoir12, edited by McKerrow and Scotese), improved stratigraphic and taxonomic data together with more accurate, digitized palaeogeographic maps, have confirmed the central role of palaeobiogeography in understanding the evolution of Early Palaeozoic ecosystems and their biotas.
Author: James Derby
Publisher: AAPG
ISBN: 0891813802
Category : Science
Languages : en
Pages : 1229
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Book Description
Hardcover plus DVD
Author:
Publisher:
ISBN:
Category : Paleontology
Languages : en
Pages : 500
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Book Description
Author: J. Peter Lesley
Publisher:
ISBN:
Category : Paleontology
Languages : en
Pages : 540
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Book Description
Author: R.D. Nance
Publisher: Geological Society of London
ISBN: 1786205998
Category : Science
Languages : en
Pages : 814
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Book Description
This volume is a tribute to the career of J. Brendan Murphy and features papers by over 100 authors from countries all over the world: a testament to the high-profile and far-reaching influence of Brendan’s work. The topics covered fall into three broad categories that encompass Brendan’s main fields of influence: (1) supercontinents and the supercontinent cycle, including reconstructions and modelling; (2) orogenesis and terranes, with a focus on the Appalachian–Variscan and Central Asian orogenic belts and the oceans with which they are associated; and (2) magmatism and magmatic processes, centring on the geochemistry and isotopic compositions of magmas in arc and rift setting. Like Brendan’s own research, the scope of the papers spans the globe and ranges from strongly field-based studies to conceptual analyses. All of the articles, however, are focused on unravelling some critical aspect of geology or aimed at clarifying some crucial geological process. Hence, they also share a theme common to Brendan’s many contributions in emphasizing the importance of process-oriented research.
Author: Sharon Audrey Newman
Publisher:
ISBN:
Category :
Languages : en
Pages : 164
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Book Description
Ediacaran and early Cambrian sandy and silty sediments commonly preserve microbial fossils and textures as well as the fossils of soft-bodied organisms. The rarity of similar fossils and textures in coarse-grained siliciclastic strata of the later Phanerozoic suggests that a taphonomic window facilitated this mode of fossil preservation. However, environmental and biological factors that promoted fossilization remain unclear. To experimentally identify mechanisms of preservation in siliciclastic sediments, cyanobacteria and soft tissues (scallop adductor muscles) were incubated in silica sand or clay minerals for up to two months. Clay mineral veneers coated both cyanobacterial filaments and the surfaces of soft tissues and were formed by two main processes: 1) the adhesion of fine particles from the sediment and 2) the precipitation of authigenic minerals. Photosynthetic, sheathed microorganisms were best preserved in the presence of high concentrations of dissolved silica (>0. 1 mM) and suspended fine particles (>5.6 mg/L) in solution. We showed that these organisms could be preserved in oxic environments and that the degradation of cyanobacteria by heterotrophic microorganisms was not necessary for fossilization. In contrast, soft tissues buried in sand/clay were preserved under anaerobic conditions and mineral veneers around them contained reduced iron. All scallops decayed in the presence of endogenous bacteria and the redox cycling of iron that included the microbial reduction of iron(III). We showed that the early precipitation of silica and the formation of microbial death masks is not critical for preservation. Additionally, when the degradation of soft tissues advanced within the first 15 to 30 days, all soft tissues decayed completely and left no morphological imprint. Taken together, these results show that the early microbial reduction of iron(III) present in sedimentary minerals and the formation of mineral veneers are critical for the preservation of organic material. The same processes may have facilitated the formation of exceptionally preserved fossils and textures throughout the Ediacaran and early Cambrian. Future studies should focus on the roles of iron redox cycling, sediment composition and microbial metabolisms in the preservation of soft tissues to better understand mechanisms for Ediacaran-style preservation in siliciclastic environments.
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 780
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Book Description
Author: John Foster
Publisher: Indiana University Press
ISBN: 0253011884
Category : Science
Languages : en
Pages : 457
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Book Description
This volume, aimed at the general reader, presents life and times of the amazing animals that inhabited Earth more than 500 million years ago. The Cambrian Period was a critical time in Earth's history. During this immense span of time nearly every modern group of animals appeared. Although life had been around for more than 2 million millennia, Cambrian rocks preserve the record of the first appearance of complex animals with eyes, protective skeletons, antennae, and complex ecologies. Grazing, predation, and multi-tiered ecosystems with animals living in, on, or above the sea floor became common. The cascade of interaction led to an ever-increasing diversification of animal body types. By the end of the period, the ancestors of sponges, corals, jellyfish, worms, mollusks, brachiopods, arthropods, echinoderms, and vertebrates were all in place. The evidence of this Cambrian "explosion" is preserved in rocks all over the world, including North America, where the seemingly strange animals of the period are preserved in exquisite detail in deposits such as the Burgess Shale in British Columbia. Cambrian Ocean World tells the story of what is, for us, the most important period in our planet's long history.
