DOCSLIB.ORG

Dictyonema - Rhabdinopora

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Dictyonema - Rhabdinopora Dictyonema - Rhabdinopora P. LEGRAND Legrand, P.: Dictyonema - Rhabdinopora. Norsk Geologisk Tidsskrift, Vol. 65, pp. 224-226. Oslo 1985. ISSN 0029-196X. Erdtmann's recently proposed classification of the Tremadoc dendroid graptolites and, in particular, the splitting of the genus Dictyonema into benthic (Dictyonema) in planktic (Rhabdinopora) forms are discussed. In view of the Jack of significant details concerning structure, especially in the type species, this distinction seems very premature. P. Legrand, Laboratoires Exploration Groupe TOTAL, 218 a 228, avenue du Haut-Leveque, 33605 Pessac Cedex, France. In a recent paper, Erdtmann (1982) proposed a Rhabdinipora for every taxon of the planktic D. reorganization of the classification of Tremadoc flabelliforme group. dendroid graptolites. According to him, the new classification better fits the assumed phylogeny The genus Dictyonema of various taxa. This interesting paper includes such a large The author (Legrand 1978, 1983) has recently number of taxonomic innovations that it is diffi­ pointed out that the type species of Dictyonema cult here to analyse every one. Also, the pro­ Hall, 1851 is Gorgonia retiformis Hall, 1843 des­ posed phylogeny brings up several points to be ignated by Miller in 1889. This choice is very discussed; for example, the position of Bryograp­ unfortunate, as Ruedemann (1947, p. 184) has tus pattens Matthew, the ancestor of the Dictyon­ already pointed out. In fact, this species is rare ema of the D. flabelliforme group (Rhabdinopor­ and many morphological details are unknown. In inae of Erdtmann) is extremely hypothetical. In particular, the proximal part is lacking in the fact, at the type locality of St. John (New Bruns­ lectotype (cf. Hall, 1852, pl. 40, fig. la, repro­ wick), Matthew (1893, 1895) ascribes this species duced by Ruedemann 1908, pl. 3, fig. l) and is to the Dictyonema Zone. The author has sam­ badly preserved in the syntype figured by Hall pled in detail the lower part of this zone in order 1865 (p. 12, fig. 10). It is therefore possible that to study the Cambrian - Ordovician boundary, Gorgonia retiformis might have been a benthic and has never found this species. It is therefore species attached to the substratum. In fact, this very probable that it belongs to the upper part of type species has never been revised and a careful the Dictyonema Zone. Also, it was described in study of the genus should be gin with this species. association with Dictyonema rusticum (?) by Bul­ (1950) man from the material collected by The genus Rhabdinopora Charles Lapworth in the Cape Rosier Section. Finally, a very similar fauna, perhaps even the This genus was created by Von Eichwald in 1855 same (a revision of the species is necessary), was for the species flabelliformis that he first ascribed quoted as being above the D. flabelliforme fauna to the genus Gorgonia (thinking that it was an in the Algerian Sahara (Legrand 1973). In fact, it alcyonarian), then to the genus Fenestella (think­ seems that some reservation must be made as ing it was a bryozoan). A long history ensued for regards the occurrence of Radiograptus before this species (resumed by Erdtmann 1982), with that of Dictyonema of the D. flabelliforme group the names Phyllograptus (Angelin 1854), Grap­ since at Cape Rosier (Gaspesie), its type locality, topora (Salter 1858), Dictyograptus (Hopkinson the species is associated with Anisograptidae & Lapworth 1875), Damesograptus (Jahn 1892) (Bulman 1950). and Dictyodendron (Westergard 1909) succes­ Whatever the case may be, this note examines sively proposed. The assignment to the genus only the problem arising from the restriction by Dictyonema proposed for the first time by Erdtman of the name Dictyonema for the typical Schmidt (1858), was definitely accepted in 1927 benthic species and the resurrection of the genus through the work of Bulman. NORSK GEOLOGISK TIDSSKRIFT 3 (1985) Dictyonema - Rhabdinopora 225 In contrast to the species retiformis, the spe­ 2. Also, it is questionable whether the ecological eies flabelliforme and similar species, subspecies difference between living in the benthic or in or forms are very well known through the studies the pelagic domain is sufficient to distinguish of Bulman (1927a), even if certain problems have two genera. This criterion would be valid if still not been resolved (Legrand 1974). Details of the difference in habitat were reflected by the proximal part, and of budding have been important morphological differences. Howev­ described, as have different aspects of the organs er, this is not the case, since the identity of the that probably enabled the colon y to fix itself to a shape of thecae in the colonies living with rigid or mobile support, or to float (Bulman their proximal part upward (pelagic) or down­ 1927a; Stormer 1933, 1945; Bulman & Stormer ward (fixed colonies) is one of the great prob­ 1971). The prevailing opinion at the present time lems surrounding the interpretation of grapto­ is that the flabelliforme group is a collection of litic paleobiology and evolution. The solution planktonic species. of this anomaly, which we can call the Dic­ tyonema paradox, has been discussed by Kirk (1969, 1972) and concerns the mobility of Dictyonema- Rhabdinopora graptolites and her interpretation of Dictyon­ ema flabelliforme floating with its sicula The extensive vertical range of Dictyonema (Up­ downward and in the same position as the per Cambrian to Carboniferous) has encouraged fixed species. numerous workers to subdivide the genus. In This plasticity of behaviour sugge�ts a mi­ view of the Jack of clear and accurate morpho­ nor difference between the animals of the two logical features to permit a subdivision, Bul­ environments. Also, to our knowledge, a pro­ man (1927b) distinguished between Cambrian liferation of supposed fixed Dictyonema by (including Tremadoc species), Ordovician and the budding of new rhabdosomes has never Silurian Dictyonema. Now Erdtmann (1982), us­ been observed. This indicates a more or less ing a phylogenetic hypothesis that still requires pelagic phase during the larva! or juvenile confirmation, proposes to restrict the name Dic­ stage. tyonemafor benthic forms and Rhabdinopora for Therefore, should we consider the possibil­ planktic forms. ity of classifying juvenile stages and adult This subdivision appears improbable for the stages in a different genera and in different following reasons: families? l. A good taxonomy must be based on facts, i.e. morphological characters and not on the in­ Conclusion terpretation of these facts which deprives it of all stability. The distinction between the Only the concept of species is natura!. The genus benthic and pelagic Dictyonemais based, with is a more or less artificial human invention; every very few exceptions, on the interpretation of discussion about the genus is therefore relatively morphological details of the proximal part. academic. It is not by creating a new taxonomy For example, is the difference between the that we can further our knowledge of Dictyon­ "fibrous holdfast structures" that would have ema, but rather by patient collecting and the been utilised to fix the benthic species on a detailed study of well preserved specimens. Fur­ soft substrace, and the "bundled nemetic fi­ thermore hetter material of the type species is bres" that the supposed pelagic species exhib­ needed as a first step. it, sufficient to distinguish two genera from different families? Manuscript received July 1984 The author has been fortunate with samples Manuscript revised December 1984 from the Sahara, to be able to compare the appearance of specimens surrounded by ma­ trix with those isolated from the matrix and has shown how much the reality was different References from what was apparent. Thus, extremely l. precise and detailed observations are required Angelin, N. P. 1854: Paleontologica Scandinavica Crustacea formationis transitionis. T. O. Weigel, Lipsiae, 92 pp. before one can evaluate details of the proxi­ Bulman, O. M. B. 1927a: Remarks on the attachment of mal ends and possible holdfasts. Dictyonemaflabelliforme (Eichw.). Geo/. Mag. 66, 492-495. 226 Note NORSK GEOLOGISK TIDSSKRIFT 3 (1985) Bulman, O. M. B. 1927: A monogrpah of British dendroid Legrand, Ph. 1974: Development of rabdosomes with four graptolites. Palaeontogr. Soe. Monogr. Part 1-ll-lll-IV, 97 primary branches in the group Dietyonema flabelliforme PP· (Eichwald). Spee. Pap. Palaeontology 13, 19-34. Bulman, O. M. B. 1950: Graptolites from the Dietyonema Legrand, Ph. 1978: A propos de l'utilisation de la zone a shales of Quebec. Quat. J. Geo/. Soe. London. 106(1), 63- Dietyonemaflabel/iforme (E. Eichwald) pour la definition de 99. la limite Cambrien - Ordovicien. Working group on the Bulman, O. M. B. & Størmer, L. 1971: Buoyancy structures in Cambrian - Ordovician Boundary. 10. rhabdosomes of Dietyonema flabelliforme (Eichwald). Nor. Legrand, Ph. 1983: Gorgonia flabelliformis Eichwald, 1940 Geo/. Tidsskr. 51, 25-31. (Graptolithina) comments on the application for a neo type Eichwald, E. v 1855: Beitrag zur geographischen Verbreitung designation by use of the plenary powers. ZN. (S) 1770. der fossilen Thiere Russlands. Alte Periode. Bull. Soe. Imp. Bull. Zool. Nom. 40, 20-23. Nat. Moseow, 28, 433-466. Matthew, G. F. 1893: Illustrations of the fauna of the St. John Erdtmann, B. D. 1982: A reorganization and proposed phylo­ group. Trans. Roy. Soc. Canada. IV, 95-109. genetic classification of planktic Tremadoc (earl y Ordovi­ Matthew, G. F. 1895: Two new Cambrian graptolites with cian) dendroid graptolites. Nor. Geo/. Tidsskr. 62, 121-144. notes on other species of graptolitidae of that age. Trans. Kirk, N. H. 1%9: Some thoughts on the ecology, mode of life New York Aead. Se. XIV, 262-273. and evolution of the Graptolithina. Proe. Geo/. Soe. I659, Miller, S. A. 1889: North Ameriean Geology and Paleontology. 273-292. Cincinnati. Kirk, N. H. 1972: More thoughts on the automobility of the Ruedemann, R. 1908: Graptolites of New York. Part Il. New graptolites. J. Geo/. Soe. London. 128, 127-139.
Load more

Recommended publications
  • Permian–Triassic Non-Marine Algae of Gondwana—Distributions
    Earth-Science Reviews 212 (2021) 103382 Contents lists available at ScienceDirect Earth-Science Reviews journal homepage: www.elsevier.com/locate/earscirev Review Article Permian–Triassic non-marine algae of Gondwana—Distributions, natural T affinities and ecological implications ⁎ Chris Maysa,b, , Vivi Vajdaa, Stephen McLoughlina a Swedish Museum of Natural History, Box 50007, SE-104 05 Stockholm, Sweden b Monash University, School of Earth, Atmosphere and Environment, 9 Rainforest Walk, Clayton, VIC 3800, Australia ARTICLE INFO ABSTRACT Keywords: The abundance, diversity and extinction of non-marine algae are controlled by changes in the physical and Permian–Triassic chemical environment and community structure of continental ecosystems. We review a range of non-marine algae algae commonly found within the Permian and Triassic strata of Gondwana and highlight and discuss the non- mass extinctions marine algal abundance anomalies recorded in the immediate aftermath of the end-Permian extinction interval Gondwana (EPE; 252 Ma). We further review and contrast the marine and continental algal records of the global biotic freshwater ecology crises within the Permian–Triassic interval. Specifically, we provide a case study of 17 species (in 13 genera) palaeobiogeography from the succession spanning the EPE in the Sydney Basin, eastern Australia. The affinities and ecological im- plications of these fossil-genera are summarised, and their global Permian–Triassic palaeogeographic and stra- tigraphic distributions are collated. Most of these fossil taxa have close extant algal relatives that are most common in freshwater, brackish or terrestrial conditions, and all have recognizable affinities to groups known to produce chemically stable biopolymers that favour their preservation over long geological intervals.
    [Show full text]
  • Stratigraphic Distribution and Suggested Evolution of Dendroid Graptolites from the Silurian of Eastern Australia
    University of Wollongong Research Online Faculty of Science - Papers (Archive) Faculty of Science, Medicine and Health 1-1-2010 Stratigraphic distribution and suggested evolution of dendroid graptolites from the Silurian of eastern Australia Barrie Rickards University of Cambridge Anthony Wright University of Wollongong, [email protected] Follow this and additional works at: https://ro.uow.edu.au/scipapers Part of the Life Sciences Commons, Physical Sciences and Mathematics Commons, and the Social and Behavioral Sciences Commons Recommended Citation Rickards, Barrie and Wright, Anthony: Stratigraphic distribution and suggested evolution of dendroid graptolites from the Silurian of eastern Australia 2010, 177-190. https://ro.uow.edu.au/scipapers/634 Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] Stratigraphic distribution and suggested evolution of dendroid graptolites from the Silurian of eastern Australia Abstract Five evolutionary lineages are proposed for Silurian species of the benthic dendroid graptolite genus Dictyonema, based largely on the exceptional eastern Australian records of the genus, comprising at least 25 species. These are: A, the delicatulum lineage with bifurcating ventral autothecal apertural spines; B, the paululum lineage with single ventral apertural spines or processes; C, the elegans lineage with isolated thecal apertures ± processes; D, the sherrardae lineage with dorsal apertural processes; and E, the venustum lineage with simple autothecal apertures. Brief comments are also made on other dendroid genera occurring in Australian strata, namely: Acanthograptus, Koremagraptus, Callograptus, Dendrograptus, Stelechocladia, Thallograptus and Palaeodictyota. Other non-graptoloid benthic hemichordates also listed are the tuboids Galaeograptus, Reticulograptus and Cyclograptus and the rhabdopleuran ?Rhabdopleura.
    [Show full text]
  • Cortical Fibrils and Secondary Deposits in Periderm of the Hemichordate Rhabdopleura (Graptolithoidea)
    Cortical fibrils and secondary deposits in periderm of the hemichordate Rhabdopleura (Graptolithoidea) PIOTR MIERZEJEWSKI and CYPRIAN KULICKI Mierzejewski, P. and Kulicki, C. 2003. Cortical fibrils and secondary deposits in periderm of the hemichordate Rhabdopleura (Graptolithoidea). Acta Palaeontologica Polonica 48 (1): 99–111. Coenecia of extant hemichordates Rhabdopleura compacta and Rh. normani were investigated using SEM techniques. Cortical fibrils were detected in their fusellar tissue for the first time. The densely packed cortical fibrils form a character− istic band−like construction in fusellar collars, similar to some Ordovician rhabdopleurids. No traces of external second− ary deposits are found in coenecia. Two types of internal secondary deposits in tubes are recognized: (1) membranous de− posits, composed of numerous, tightly packed sheets, similar to the crustoid paracortex and pseudocortex; and (2) fibrillar deposits, devoid(?) of sheets and made of cortical fibrils, arranged in parallel and interpreted as equivalent to graptolite endocortex. There is no significant difference in either the shape or the dimensions of cortical fibrils found in Rhabdopleura and graptolites. The cortical fabric of both rhabdopleuran species studied is composed of long, straight and more or less wavy, unbranched fibrils arranged in parallel; their diameters vary from 220 to 570 µm. The study shows that there is no significant difference between extinct and extant Graptolithoidea (= Pterobranchia) in the histological and ultrastructural pattern of their primary and secondary deposits of the periderm. The nonfusellar periderm of the prosicula is pitted by many depressions similar to pits in the cortical tissue of graptolites. Key words: Rhabdopleura, Pterobranchia, Hemichordata, periderm, sicula, ultrastructure, fibrils. Piotr Mierzejewski [[email protected]], Instytut Paleobiologii PAN, ul.
    [Show full text]
  • Lab 8: Graptolites and Trace Fossils
    Geos 223 Introductory Paleontology Spring 2006 Lab 8: Graptolites and Trace Fossils Name: Section: AIMS: This lab will introduce you to graptolites (Part A), and to a branch of paleontology known as ichnology (the study of trace fossils; Part B). By the end of Part A this lab you should be familiar with the basic anatomy of graptolites, and have an appreciation for how graptolites are used in the biostratigraphic zonation of the Lower Paleozoic. By the end of Part B of this lab you should be familiar with the basic ethological groups of trace fossils, and have an appreciation for how trace fossils can provide important paleoecological and paleoenvironmental information. PART A: GRAPTOLITES. Graptolites (Class Graptolithina) are an extinct group of colonial hemichordate deuterostomes, similar in morphology and life habit to the modern colonial pterobranch hemichordate Rhabdopleura. The graptolite colony consisted of many clonal zooids, each occupying a theca in the communal skeleton (the rhabdosome). The thecae formed in rows along branches of the rhabdosome called stipes. The rhabdosome was made of a non-mineralized, organic, non-chitinous protein called periderm. Graptolite colonies were either erect fan-like structures growing from the seafloor (most dendroid graptolites, ranging from the Middle Cambrian to the Late Carboniferous) or free-floating in the plankton (the commoner graptoloid graptolites, probably descended from dendroid ancestors and ranging from the Early Ordovician to the Early Devonian). Graptoloid graptolites are very important biostratigraphic zone fossils in Lower Paleozoic strata. 1 DENDROID GRAPTOLITES: A1: Dictyonema. Dendroid graptolite colonies formed fan-like structures with thecae-bearing stipes held apart by horizontal struts (dissepiments).
    [Show full text]
  • Ordovician Stratigraphy and Benthic Community Replacements in the Eastern Anti-Atlas, Morocco J
    Ordovician stratigraphy and benthic community replacements in the eastern Anti-Atlas, Morocco J. Javier Alvaro, Mohammed Benharref, Jacques Destombes, Juan Carlos Gutiérrez-Marco, Aaron Hunter, Bertrand Lefebvre, Peter van Roy, Samuel Zamora To cite this version: J. Javier Alvaro, Mohammed Benharref, Jacques Destombes, Juan Carlos Gutiérrez-Marco, Aaron Hunter, et al.. Ordovician stratigraphy and benthic community replacements in the eastern Anti- Atlas, Morocco. The Great Ordovician Biodiversification Event: Insights from the Tafilalt Biota, Morocco, 485, The Geological Society of London, pp.SP485.20, In press, Geological Society, London, Special Publication, 10.1144/SP485.20. hal-02405970 HAL Id: hal-02405970 https://hal.archives-ouvertes.fr/hal-02405970 Submitted on 13 Nov 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. The Geological Society Special Publications Ordovician stratigraphy and benthic community replacements in the eastern Anti-Atlas, Morocco --Manuscript Draft-- Manuscript Number: GSLSpecPub2019-17R1 Article Type: Research article Full Title: Ordovician stratigraphy and benthic community replacements in the eastern Anti-Atlas, Morocco Short Title: Ordovician stratigraphy of the Anti-Atlas Corresponding Author: Javier Alvaro Instituto de Geociencias SPAIN Corresponding Author E-Mail: [email protected] Other Authors: MOHAMMED BENHARREF JACQUES DESTOMBES JUAN CARLOS GUTIÉRREZ-MARCO AARON W.
    [Show full text]
  • The Palaeontology Newsletter
    The Palaeontology Newsletter Contents100 Editorial 2 Association Business 3 Annual Meeting 2019 3 Awards and Prizes AGM 2018 12 PalAss YouTube Ambassador sought 24 Association Meetings 25 News 30 From our correspondents A Palaeontologist Abroad 40 Behind the Scenes: Yorkshire Museum 44 She married a dinosaur 47 Spotlight on Diversity 52 Future meetings of other bodies 55 Meeting Reports 62 Obituary: Ralph E. Chapman 67 Grant Reports 72 Book Reviews 104 Palaeontology vol. 62 parts 1 & 2 108–109 Papers in Palaeontology vol. 5 part 1 110 Reminder: The deadline for copy for Issue no. 101 is 3rd June 2019. On the Web: <http://www.palass.org/> ISSN: 0954-9900 Newsletter 100 2 Editorial This 100th issue continues to put the “new” in Newsletter. Jo Hellawell writes about our new President Charles Wellman, and new Publicity Officer Susannah Lydon gives us her first news column. New award winners are announced, including the first ever PalAss Exceptional Lecturer (Stephan Lautenschlager). (Get your bids for Stephan’s services in now; check out pages 34 and 107.) There are also adverts – courtesy of Lucy McCobb – looking for the face of the Association’s new YouTube channel as well as a call for postgraduate volunteers to join the Association’s outreach efforts. But of course palaeontology would not be the same without the old. Behind the Scenes at the Museum returns with Sarah King’s piece on The Yorkshire Museum (York, UK). Norman MacLeod provides a comprehensive obituary of Ralph Chapman, and this issue’s palaeontologists abroad (Rebecca Bennion, Nicolás Campione and Paige dePolo) give their accounts of life in Belgium, Australia and the UK, respectively.
    [Show full text]
  • Dendroid and Tuboid Graptolites from the Llandovery (Silurian) of the Four Mile Creek Area, New South Wales
    © Copyright Australian Museum, 2003 Records of the Australian Museum (2003) Vol. 55: 305–330. ISSN 0067-1975 Dendroid and Tuboid Graptolites from the Llandovery (Silurian) of the Four Mile Creek Area, New South Wales R.B. RICKARDS1, A.J. CHAPMAN1, A.J. WRIGHT2* AND G.H PACKHAM3 1 Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ England [email protected] 2 School of Geosciences, University of Wollongong, Wollongong NSW 2522, Australia [email protected] 3 School of Geosciences, University of Sydney NSW 2006, Australia [email protected] ABSTRACT. Twenty-four taxa of Llandovery (Early Silurian) dendroid and tuboid graptolites from the Cadia Coach Shale and Glendalough Formation in the Four Mile Creek area, S of Orange, New South Wales, provide the most diverse benthic graptolite record known from rocks of this age. Eighteen new taxa described here are: the dendroids Dendrograptus avonleaensis, D. ashburniaensis, Dictyonema williamsae, D. paululum australis, D. jenkinsi, D. muirae, D. warrisi, Callograptus bridgecreekensis, C. rigbyae, C. ulahensis, Stelechocladia praeattenuata, Acanthograptus praedeckeri, A. praedeckeri minimus, Thallograptus christoffersonae, Koremagraptus obscurus and C. elegantulus; and the tuboids Reticulograptus thomasi and Cyclograptus? australis. The six previously-named taxa are: Dictyonema cf. delicatulum Lapworth, D. falciferum Bulman, D. venustum Lapworth, Callograptus cf. niagarensis Spencer and Pseudodictyonema graptolithorum (Pota); and one species in open nomenclature is Dictyonema sp. 1. These occur with graptoloids at Four Mile Creek, allowing precise stratigraphic correlation of the faunas with probably the gregarius Biozone (middle Llandovery), and the crispus and griestoniensis Biozones (late Llandovery) of Europe. Criteria for dendroid classification are discussed and some implications for reconstructing the evolutionary history of the group are reviewed.
    [Show full text]
  • Stratigraphy, Structure, and Graptolites of an Ordovician and Silurian Sequence in the Terra Cotta Mountains, Alaska Range, Alaska
    Stratigraphy, Structure, And Graptolites of an Ordovician and Silurian Sequence in the Terra Cotta Mountains, Alaska Range, Alaska By Michael Churkin, Jr., and Claire Carter Geology and paleontology of three newly named Paleozoic formations and descriptions of six new graptolites UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1996 U.S.DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director For sale by U.S. Geological Survey, Information Services Box 25286, Federal Center Denver, CO 80225 Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government Text and illustrations edited by Mary Lou Callas Camera lucida fossil illustrations by Claire Carter Other illustrations by Michelle Coveau Layout by Mary Lou Callas Library of Congress Cataloging-in-Publication Data Churkin, Michael. Stratigraphy, structure, and graptolites of an Ordovician and Silurian sequence in the Terra Cotta Mountains, Alaska Range, Alaska I by Michael Churkin, Jr., and Claire Carter. p. cm. - (U.S. Geological Survey professional paper ; 1555) Includes bibliographical references and index. Supt. of Docs. no.: 119.16: 1555 1. Graptolites-Alaska-Terra Cotta Mountains. 2. Paleontology-Ordovician. 3. Paleontology-Silurian. 4. Animals, Fossil-Alaska-Terra Cotta Mountains. 5. Geology-Alaska-Terra Cotta Mountains. 6. Geology, Stratigraphic-Ordovician. 7, Geology, Stratigraphic-Silurian. I. Carter, Claire. I1 Title. I11 Series. QE840.5.C48
    [Show full text]
  • High Molybdenum Availability for Evolution in a Mesoproterozoic Lacustrine Environment
    ARTICLE Received 28 Jun 2014 | Accepted 20 Mar 2015 | Published 19 May 2015 DOI: 10.1038/ncomms7996 High Molybdenum availability for evolution in a Mesoproterozoic lacustrine environment John Parnell1, Samuel Spinks1,w, Steven Andrews1, Wanethon Thayalan1 & Stephen Bowden1 Trace metal data for Proterozoic marine euxinic sediments imply that the expansion of nitrogen-fixing cyanobacteria and diversification of eukaryotes were delayed while the availability of bioessential metals such as molybdenum in the ocean was limited. However, there is increasing recognition that the Mesoproterozoic evolution of nitrogen fixation and eukaryotic life may have been promoted in marginal marine and terrestrial environments, including lakes, rather than in the deep ocean. Molybdenum availability is critical to life in lakes, just as it is in the oceans. It is, therefore, important to assess molybdenum availability to the lacustrine environment in the Mesoproterozoic. Here we show that the flux of molybdenum to a Mesoproterozoic lake was 1 to 2 orders of magnitude greater than typical fluxes in the modern and ancient marine environment. Thus, there was no barrier to avail- ability to prevent evolution in the terrestrial environment, in contrast to the nutrient-limited Mesoproterozoic oceans. 1 School of Geosciences, University of Aberdeen, Aberdeen AB24 3UE, UK. w Present address: CSIRO Mineral Resources Flagship, Australian Resources Research Centre, Perth, Western Australia 6151, Australia. Correspondence and requests for materials should be addressed to J.P. (email: [email protected]). NATURE COMMUNICATIONS | 6:6996 | DOI: 10.1038/ncomms7996 | www.nature.com/naturecommunications 1 & 2015 Macmillan Publishers Limited. All rights reserved. ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/ncomms7996 he content of Molybdenum (Mo) in ancient carbonaceous The calculated Mo flux for the Stoer Group black shales is 1 to shales is a valuable indicator of palaeo-redox conditions.
    [Show full text]
  • Uranium in Poland: Resources and Recovery from Low-Grade Ores 67
    DOI: 10.5772/intechopen.72754 Provisional chapter Chapter 4 Uranium in Poland: Resources and Recovery from Low-GradeUranium in OresPoland: Resources and Recovery from Low- Grade Ores Katarzyna Kiegiel, Agnieszka Miskiewicz, Dorota Gajda, Katarzyna Kiegiel, Agnieszka Miskiewicz, Sylwester Sommer, Stanislaw Wolkowicz and Dorota Gajda, Sylwester Sommer, Grazyna Zakrzewska-Koltuniewicz Stanislaw Wolkowicz and GrazynaAdditional information Zakrzewska-Koltuniewicz is available at the end of the chapter Additional information is available at the end of the chapter http://dx.doi.org/10.5772/intechopen.72754 Abstract The presented studies deal with an assessment of the possibility of uranium recovery from the low-grade uranium resources in Poland. Uranium was leached from the ground uranium ores with efficiencies in 81–100% range that depend on the type of ore and leaching solution used. In the next step, the post-leaching solution was treated by the sol- vent extraction or ion exchange chromatography to separate uranium from other metals present in the ore. The novel routes of leaching by using membrane methods were exam- ined. The final product, “yellow cake,” was obtained in precipitation step. The studies of precipitation of uranium as ammonium diuranate or uranium peroxide from diluted uranium solutions are presented in this chapter. The work was completed with tentative economic analysis and environmental impact assessment along with radiation protection issues connected to uranium production. Keywords: uranium ores, leaching, extraction, ion exchange chromatography, precipitation 1. Introduction Continued interest in nuclear power and uranium industry revival is leading to the inevitable growing uranium demand. New sources of primary uranium will be derived from explora- tion and exploitation of lower grade ore bodies and also secondary resources as potential raw materials.
    [Show full text]
  • Uranium Resources in Poland‐ the Past and Present
    Uranium resources in Poland‐ the past and present Ewelina Chajduk, Halina Polkowska-Motrenko Institute of Nuclear Chemistry and Technology, Warsaw, Poland Poland 2012 Poland 1918-1939 1853- uranophane was discovered in cooper mine „Miedzianka" near Jelenia Góra Ca(UO2)2[HSiO4]2·5H2O is a rare calcium uranium silicate hydrate mineral that forms from the oxidation of uranium bearing minerals 1912-The highest U concentration found in iron ore mine „Bergfreiheit” in Kowary. (Pitchblende) To the end of 1942 in the Sudetenland, mining about 100 tons "of uranium ore" in search of radium but uranium was treated as waste with no commercial value 1943-1944 - mining c.a. 72 tons of uranium ore for the purposes of Nazi German nuclear fuel 1945-Bombing of Oranienburg -the center of Nazi Germany's nuclear energy project Mining and processing of uranium ore in Poland in the years 1948-1972 On 1 January 1948 under a special agreement established the Polish- Soviet enterprise called "Kowarski Mines". It was to deal with the exploration and exploitation of uranium on Polish territory. The head office was taken over by the Russians in the mine "Freedom" in Kowary. The exploitation of uranium ore were taken at existing mines, and so in the mine "Freedom" in Kowary and "Minerals" in Kletno and Miedzianka. At the same time a group of geological examine all possible locations of uranium deposits. As a result of the work carried out in the Sudetenland was discovered nearly 70 places of occurrence of this element. Fifteen have been recognized as deposits, including eight worn at the stage of identification.
    [Show full text]
  • Review of Fossil Collections in Scotland Review of Fossil Collections in Scotland
    Detail of the Upper Devonian fishHoloptychius from Dura Den, Fife. © Perth Museum & Art Gallery, Perth & Kinross Council Review of Fossil Collections in Scotland Review of Fossil Collections in Scotland Contents Introduction 3 Background 3 Aims of the Collections Review 4 Methodology 4 Terminology 5 Summary of fossil material 6 Influences on collections 14 Collections by region Aberdeen and North East 17 Elgin Museum (Moray Society) 18 Falconer Museum (Moray Council) 21 Stonehaven Tolbooth Museum 23 The Discovery Centre (Live Life Aberdeenshire) 24 Arbuthnot Museum (Live Life Aberdeenshire) 27 Zoology Museum (University of Aberdeen Museums) 28 Meston Science Building (University of Aberdeen Museums) 30 Blairs Museum 37 Highlands and Islands 38 Inverness Museum and Art Gallery (High Life Highland) 39 Nairn Museum 42 West Highland Museum (West Highland Museum Trust) 44 Brora Heritage Centre (Brora Heritage Trust) 45 Dunrobin Castle Museum 46 Timespan (Timespan Heritage and Arts Society) 48 Stromness Museum (Orkney Natural History Society) 50 Orkney Fossil and Heritage Centre 53 Shetland Museum and Archives (Shetland Amenity Trust) 56 Bute Museum (Bute Museum Trust) 58 Hugh Miller’s Birthplace Cottage and Museum (National Trust for Scotland) 59 Treasures of the Earth 62 Staffin Dinosaur Museum 63 Gairloch Museum (Gairloch & District Heritage Company Ltd) 65 Tayside, Central and Fife 66 Stirling Smith Art Gallery and Museum 67 Perth Museum and Art Gallery (Culture Perth and Kinross) 69 The McManus: Dundee’s Art Gallery and Museum (Leisure
    [Show full text]