DOCSLIB.ORG

Acritarchs from the Lower Cambrian Buen Formation in North Greenland GEUS Report File No

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Acritarchs from the Lower Cambrian Buen Formation in North Greenland GEUS Report file no. 22316 Gonzalo Vidal and John S. Peel GRØNLANDS GEOLOGISKE UNDERSØGELSE Bulletin 164 1993 GRØNLANDS GEOLOGISKE UNDERSØGELSE Bulletin 164 o Acritarchs from the Lower Cambrian Buen Formation in North Greenland .. ~ ~ f) Gonzalo Vidal and John S. Peel 1993 Vidal, G. & Peel, J. S. 1993: Acritarchs from the Lower are particular1y important and relevant with classical Cambrian Buen Formation in North Greenland. Bull. Lower Cambrian rock successions in Baltoscandia, vari­ Grønlands geol. Unders. 164, 35 pp. ous areas of the East European Platform, Svalbard, Scotland and North-East Greenland. In all, the reco­ vered acritarch assemblage conclusively confirms the AcritafGhs (organic-walled phytoplankton) are de­ previously proposed late Ear1y Cambrian age for the scribed from the siliciclastic rocks of the Buen Forma­ Buen Formation, most likely corresponding to the He­ tion. A total of 52 form taxa are reported from a small liosphaeridium dissimilare - Skiagia ciliosa (= Vergale number of extremely fossiliferous samples from the 'horizon') and perhaps the Volkovia dentifera - Lie­ deeper shelf portion of the formation. The preservation paina plana (= Rausve 'horizon') acritarch zones in the of acritarchs is excellent and, in the light of their abun­ East European Platform and counterparts in Baltoscan­ dance, the taphonomy and palaeobiology of the Buen dia. Formation are discussed. Three new acritarch form taxa are erected and two more., obviously also new, are left under open nomenclature. Large-size acanthomorphic Authors' addresses: acritarchs represented by extremely rare finds of two G. V., Institute of Earth Sciences - Micropalaeontol­ new taxa (Comasphaeridium? densispinosum n. sp. and ogy, Uppsala University, Norbyvagen 22, S-751 22 Comasphaeridium longispinosum n. sp.) are recorded Uppsala, Sweden. for the first time in Lower Cambrian strata. Large acan­ J. S. P., Geological Survey of Greenland, øster Vold­ thomorphs are otherwise important in Neoproterozoic gade 10, DK-1350 Copenhagen K, Denmark. Present strata and the significance of the present finds is dis­ address: Institute of Earth Sciences - Dept of Historicai cussed. The remaining acritarchs are known from nu­ Geology and Palaeontology, Uppsala University, Nor­ merous wor1d-wide earlier occurrences. Comparisons byvagen 22, S-751 22 Uppsala, Sweden. Grønlands Geologiske Undersøgelse Ujarassiortut Kalaallit Nunaanni Misissuisoqarfiat Geological Survey of Greenland The Geological Survey of Greenland (GGU) is a research institute affiliated to the Mineral Resources Administration for Greenland (MRA) within the Danish Ministry of Energy. As with all other activities involving the non-living resources in Greenland, GGU's investlgations are carried out within the frarnework of the policies decided jointly by the Greenland Home Rule Authority and the Danish State. © GGU, Copenhagen, 1993 ISSN 0105-3507 Contents Dansk sammendrag - Imaqarnersiuineq ., ............ 4 Goniosphaeridium ~p. A. ......................... 23 Introduetion. .................................. 5 Goniosphaeridium varium (Volkova, 1969) Geological framework .............................. 5 Downie, 1982 ................................. 23 Sample register. ................................... 7 Goniosphaeridium volkovae Hagenfeldt, 1989 ....... 25 Material and methods .............................. 9 Granomarginata squamacea Volkova, 1968. ......... 25 Acritarch preservation. ............................. 9 Heliosphaeridium sp. ............................. 25 Taphonomy and palaeobiology 9 Heliosphaeridium coniferum (Downie, 1982) Large acanthomorphic acritarchs. .................... 11 Moczydlowska, 1991 .. ......................... 25 Biostratigraphy .................................... 12 Heliosphaeridium dissimilare (Volkova, 1969) Conc1usions ....................................... 13 Moczydlowska, 1991 ........................... 25 Taxonomy 15 Heliosphaeridium lubomlense (Kirjanov, 1974) Archaeodiscina umbonulata Volkova, 1968. ......... 15 Moczydlowska, 1991 ........................... 25 Asteridium Moczydlowska 1991. ................... 15 Heliosphaeridium notatum (Volkova, 1969) Moczydlowska, 1991 ........................... 25 Asteridium lanatum (Volkova, 1969) Moczydlowska, 1991 .. ......................... 15 Heliosphaeridium obscurum (Volkova, 1969) Asteridium ordensis (Downie, 1982), comb. nov. .... 15 Moczydlowska, 1991 .. ......................... 27 Asteridium tornatum (Volkova, 1968) Leiosphaeridia Eisenack, 1958 emend. Downie & Moczydlowska, 1991 ........................... 17 Sarjeant, 1963. ................................ 27 Leiovalia tenera Kirj anov, 1974. ................... 27 ?Celtiberium geminum Fombella, 1977. ............. 17 Lophosphaeridium dubium (Volkova, 1968) Comasphaeridium sp. A Downie, 1982 ". .. .. .. .. .. 17 Moczydlowska, 1991 ........................... 27 Comasphaeridium agglutinatum Moczydlowska, 1988. 19 Lophosphaeridium tentativum Volkova, 1968 ........ 27 Comasphaeridium mackenziana Baudet, Aitken & Vanguestaine, 1989 19 Lophosphaeridium truncatum Volkova, 1969 ........ 27 Lophosphaeridium sp. ............................ 29 Comasphaeridium molliculum Moczydlowska & Vidal, 1988. ................................... 19 Multiplicisphaeridium dendroideum Comasphaeridium? densispinosum Vidal n. sp. .. .... 19 (Jankauskas, 1976). ............................ 29 Pterospermella Eisenack, 1972. .................... 29 Comasphaeridium longispinosum Vidal n. sp. 19 Retisphaeridium dichamerum Staplin, Jansonius & Comasphaeridium strigosum (Jankauskas) Downie, 1982 .,. .............................. 21 Pocock, 1965. ................................. 29 Skiagia Downie, 1982 '" . .. .. .. 29 Comasphaeridium cL strigosum (Jankauskas) Downie, 1982 ................................. 21 Skiagia ciliosa (Volkova, 1969) Downie, 1982 ....... 29 Cymatiosphaerapostii (Jankauskas, 1976) Skiagia compressa (Volkova, 1968) Downie, 1982. ... 29 Jankauskas, 1979 .............................. 21 Skiagia orbiculare (Volkova, 1968) Downie, 1982. ... 31 Cymatiosphaera sp. 21 Skiagia ornata (Volkova, 1968) Downie, 1982 ....... 31 Dictyotidium Eisenack, 1955 emend. Staplin, 1961 ... 21 Skiagia scottica Downie, 1982 ..................... 31 Dictyotidium perforatum Vidal n. sp. ............... 21 Tasmanites bobrowskae Wa:i:ynska, 1967 .. .......... 31 Elektoriskos sp. A............................... 23 Tasmanites tenelIus Volkova, 1968. ................. 31 Fimbriaglomerella Loeblich & Drugg, 1968 23 Tasmanites volkovae Kirjanov, 1974.. .. .. .. .. .. 31 Globosphaeridium cerinum (Volkova) Trachysphaeridium timofeevi Vidal, 1976............ 31 Moczydlowska, 1991 ... :. ...................... 23 Acknowledgements ................................ 33 Goniosphaeridium primarium (Jankauskas) References. ....................................... 33 Downie, 1982 ................................. 23 Dansk sammendrag Dette arbejde beskriver acritarcher (fytoplankton forekomster verden over. Det er især vigtigt at sammen­ med organisk væg) fra Buen Formationen (nedre Kam­ ligne med de klassiske aflejringer fra nedre Kambrium i brium) i Nordgrønland. I alt rapporteres der om 52 Baltoscandia, forskellige områder på den østeuropæiske arter fra få men særdeles fossilrige prØver, der repræ• platform, Svalbard, Skotland og Nordøstgrønland. senterer den dybere del af shelfen i Buen Formationen. Acritarch-sammensætningen bekræfter fuldtud den ti­ På baggrund af det store indhold af velbevarede acri­ dligere foreslåede datering af Buen Formationen til den tarcher diskuteres formationens tafonomi og palæobio• sene del af tidlig Kambrium, højst sansynligt svarende logi. Tre nye arter af acritarcher opstilles, mens to til Heliosphaeridium dissimilare - Skiagia ciliosa (= andre, tydeligvis også nye, placeres under åben nomen­ Vergale 'horizon') og måske Volkovia dentifera - Lie­ klatur. Store acantomorfe acritarcher er for første gang paina plana (= Rausve 'horizon') acritarch-zonerne på registreret i lag fra nedre Kambrium. Disse former er den østeuropæiske platform og tilsvarende zoner i Bal­ ellers kun beskrevet fra neoproterozoiske aflejringer. toscandia. De resterende acritarcher kendes fra talrige tidligere Imaqarnersiuineq Nalunaarusiami uvani imaani naasuaqqat, acritarchit, taamaattut ujaqqani pisoqaanerusuni taamaallat siorna­ Avannaarsuani ujaqqani immikkoortuni Buen Forma­ tigut allaaserineqartarsimagamik. Acritarchit sinneri si­ tionimeersut ukiut immikkoortut Kambriumip aallartin­ larsuarmi ujaqqani allarpassuarni siornatigut allaatigi­ nerani pinngorsimasut eqqartorneqarput. Ujaqqani neqarsimasuni ilisimaneqarput. Ujaqqat architarchiqar­ amerlanngikkaluartutuni naasuaqqanilli ujaranngorsi­ fiusut pingaarnerit 570 milliunit missaanni masunik amerlaqisunik akulinni, architarchit immik­ pisoqaassusillit Baltoscandiami, Europami kangilliup koortut 52-t siumorneqarsimapput, taakkulu Buen For­ nunavissuani, Svalbardimi, Skotlandimi Tunumilu mationip atsinnerusortaani nassaarineqarsimapput. Ar­ Avannaarsuani sanilliussallugit pingaartorujussuuvoq. chitarcherpassuit ujaranngorsimagaluarlutik ilusaat Architarchit assigiinngitsorpassuit ataatsimoortut tunn­ allanngorsimanngitsut tunngavigalugit qangarsuaq sumi gavigalugit ujaqqat imikkoortut Buen Formationip piso­ inuusimanerat eqqartorneqarpoq. Architarchit immik­ qaassusaasa Kambriumip aallartinnerani pinngorsima­ koortut nutaat pingasut suunerat aalajangerneqarsima­ sutut
Recommended publications
  • Soft−Part Preservation in Two Species of the Arthropod Isoxys from the Middle Cambrian Burgess Shale of British Columbia, Canada

    Soft−Part Preservation in Two Species of the Arthropod Isoxys from the Middle Cambrian Burgess Shale of British Columbia, Canada

    Soft−part preservation in two species of the arthropod Isoxys from the middle Cambrian Burgess Shale of British Columbia, Canada DIEGO C. GARCÍA−BELLIDO, JEAN VANNIER, and DESMOND COLLINS García−Bellido, D.C., Vannier, J., and Collins, D. 2009. Soft−part preservation in two species of the arthropod Isoxys from the middle Cambrian Burgess Shale of British Columbia, Canada. Acta Palaeontologica Polonica 54 (4): 699–712. doi:10.4202/app.2009.0024 More than forty specimens from the middle Cambrian Burgess Shale reveal the detailed anatomy of Isoxys, a worldwide distributed bivalved arthropod represented here by two species, namely Isoxys acutangulus and Isoxys longissimus. I. acutangulus had a non−mineralized headshield with lateral pleural folds (= “valves” of previous authors) that covered the animal’s body almost entirely, large frontal spherical eyes and a pair of uniramous prehensile appendages bearing stout spiny outgrowths along their anterior margins. The 13 following appendages had a uniform biramous design—i.e., a short endopod and a paddle−like exopod fringed with marginal setae with a probable natatory function. The trunk ended with a flap−like telson that protruded beyond the posterior margin of the headshield. The gut of I. acutangulus was tube−like, running from mouth to telson, and was flanked with numerous 3D−preserved bulbous, paired features inter− preted as digestive glands. The appendage design of I. acutangulus indicates that the animal was a swimmer and a visual predator living off−bottom. The general anatomy of Isoxys longissimus was similar to that of I. acutangulus although less information is available on the exact shape of its appendages and visual organs.
  • Carbonate-Hosted Zn-Pb Mineralization in the Lower

    Carbonate-Hosted Zn-Pb Mineralization in the Lower

    Carbonate-hosted Zn-Pb mineralization in the Lower Cambrian Sekwi Formation, Mackenzie Mountains, NWT: Stratigraphic, structural, and lithologic controls, and constraints on ore fluid characteristics by Beth J. Fischer Thesis submitted in partial fulfillment of the requirements for the degree of Master of Science (M.Sc.) in Geology School of Graduate Studies Laurentian University Sudbury, Ontario © Beth Fischer, 2012 Library and Archives Bibliotheque et Canada Archives Canada Published Heritage Direction du 1+1 Branch Patrimoine de I'edition 395 Wellington Street 395, rue Wellington Ottawa ON K1A0N4 Ottawa ON K1A 0N4 Canada Canada Your file Votre reference ISBN: 978-0-494-87713-5 Our file Notre reference ISBN: 978-0-494-87713-5 NOTICE: AVIS: The author has granted a non­ L'auteur a accorde une licence non exclusive exclusive license allowing Library and permettant a la Bibliotheque et Archives Archives Canada to reproduce, Canada de reproduire, publier, archiver, publish, archive, preserve, conserve, sauvegarder, conserver, transmettre au public communicate to the public by par telecommunication ou par I'lnternet, preter, telecommunication or on the Internet, distribuer et vendre des theses partout dans le loan, distrbute and sell theses monde, a des fins commerciales ou autres, sur worldwide, for commercial or non­ support microforme, papier, electronique et/ou commercial purposes, in microform, autres formats. paper, electronic and/or any other formats. The author retains copyright L'auteur conserve la propriete du droit d'auteur ownership and moral rights in this et des droits moraux qui protege cette these. Ni thesis. Neither the thesis nor la these ni des extraits substantiels de celle-ci substantial extracts from it may be ne doivent etre imprimes ou autrement printed or otherwise reproduced reproduits sans son autorisation.
  • Preliminary Bedrock Geology for NTS 95D/6 (Otter Creek Area), Southeast Yukon L

    Preliminary Bedrock Geology for NTS 95D/6 (Otter Creek Area), Southeast Yukon L

    Preliminary bedrock geology for NTS 95D/6 (Otter Creek area), southeast Yukon L. Pigage Preliminary bedrock geology for NTS 95D/6 (Otter Creek area), southeast Yukon Lee C. Pigage1 Yukon Geological Survey Pigage, L.C., 2008. Preliminary bedrock geology for NTS 95D/6 (Otter Creek area), southeast Yukon. In: Yukon Exploration and Geology 2007, D.S. Emond, L.R. Blackburn, R.P. Hill and L.H. Weston (eds.), Yukon Geological Survey, p. 237-255. ABSTRACT The Otter Creek area contains sedimentary and volcanic strata of the ancient North American miogeocline: Neoproterozoic to Lower Cambrian shale (Narchilla Formation) and siltstone (Vampire Formation); Late Cambrian to Middle Ordovician argillaceous to massive limestone (Rabbitkettle Formation) and dolostone (Sunblood Formation); Cambrian to Ordovician basalt and associated diabase; Silurian to Devonian MacDonald carbonate platform strata (unit SDc-south) and Selwyn basin shale (Road River Group-north); and thinly bedded silty shale likely of the Devonian to Carboniferous Besa River Formation. The rocks are deformed by six mappable north-trending, east-verging, asymmetric, macroscopic folds with amplitudes of 500-2000 m. Argillaceous and silty units contain a pervasive, axial-planar slaty cleavage. Shortening caused by the folding is about 25%. The Narchilla Formation is structurally emplaced upon Upper Cambrian-Devonian sedimentary rocks on the western margin of the map area, along an east-verging thrust fault with unknown displacement. Late northeast-striking normal faults preserve younger stratigraphic units to the south. Deformation is poorly constrained to the Mesozoic-Cenozoic Cordilleran orogeny. Four epigenetic(?), stratabound zinc±lead±barite deposits and showings occur at the stratigraphic contact between massive limestone and argillaceous limestone within the Rabbitkettle Formation.
  • Abstract Volume

    Abstract Volume

    https://doi.org/10.3301/ABSGI.2019.04 Milano, 2-5 July 2019 ABSTRACT BOOK a cura della Società Geologica Italiana 3rd International Congress on Stratigraphy GENERAL CHAIRS Marco Balini, Università di Milano, Italy Elisabetta Erba, Università di Milano, Italy - past President Società Geologica Italiana 2015-2017 SCIENTIFIC COMMITTEE Adele Bertini, Peter Brack, William Cavazza, Mauro Coltorti, Piero Di Stefano, Annalisa Ferretti, Stanley C. Finney, Fabio Florindo, Fabrizio Galluzzo, Piero Gianolla, David A.T. Harper, Martin J. Head, Thijs van Kolfschoten, Maria Marino, Simonetta Monechi, Giovanni Monegato, Maria Rose Petrizzo, Claudia Principe, Isabella Raffi, Lorenzo Rook ORGANIZING COMMITTEE The Organizing Committee is composed by members of the Department of Earth Sciences “Ardito Desio” and of the Società Geologica Italiana Lucia Angiolini, Cinzia Bottini, Bernardo Carmina, Domenico Cosentino, Fabrizio Felletti, Daniela Germani, Fabio M. Petti, Alessandro Zuccari FIELD TRIP COMMITTEE Fabrizio Berra, Mattia Marini, Maria Letizia Pampaloni, Marcello Tropeano ABSTRACT BOOK EDITORS Fabio M. Petti, Giulia Innamorati, Bernardo Carmina, Daniela Germani Papers, data, figures, maps and any other material published are covered by the copyright own by the Società Geologica Italiana. DISCLAIMER: The Società Geologica Italiana, the Editors are not responsible for the ideas, opinions, and contents of the papers published; the authors of each paper are responsible for the ideas opinions and con- tents published. La Società Geologica Italiana, i curatori scientifici non sono responsabili delle opinioni espresse e delle affermazioni pubblicate negli articoli: l’autore/i è/sono il/i solo/i responsabile/i. ST3.2 Cambrian stratigraphy, events and geochronology Conveners and Chairpersons Per Ahlberg (Lund University, Sweden) Loren E.
  • The Extent of the Sirius Passet Lagerstätte (Early Cambrian) of North Greenland

    The Extent of the Sirius Passet Lagerstätte (Early Cambrian) of North Greenland

    The extent of the Sirius Passet Lagerstätte (early Cambrian) of North Greenland JOHN S. PEEL & JON R. INESON Ancillary localities for the Sirius Passet biota (early Cambrian; Cambrian Series 2, Stage 3) are described from the im- mediate vicinity of the main locality on the southern side of Sirius Passet, north-western Peary Land, central North Greenland, where slope mudstones of the Transitional Buen Formation abut against the margin of the Portfjeld Forma- tion carbonate platform. Whilst this geological relationship may extend over more than 500 km east–west across North Greenland, known exposures of the sediments yielding the lagerstätte are restricted to a 1 km long window at the south-western end of Sirius Passet. • Keywords: Early Cambrian, Greenland, lagerstätte. PEEL, J.S. & INESON, J.R. The extent of the Sirius Passet Lagerstätte (early Cambrian) of North Greenland. Bulletin of Geosciences 86(3), 535–543 (4 figures). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received March 24, 2011; accepted in revised form July 8, 2011; published online July 28, 2011; issued September 30, 2011. John S. Peel, Department of Earth Sciences (Palaeobiology), Uppsala University, Villavägen 16, SE-75 236 Uppsala, Sweden; [email protected] • Jon R. Ineson, Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark; [email protected] Almost all of the fossils described from the early Cambrian The first fragmentary fossils from the Sirius Passet Sirius Passet Lagerstätte of northern Peary Land, North Lagerstätte (GGU collection 313035) were collected by Greenland, were collected from a single, west-facing talus A.K.
  • Oil and Gas Resource Potential of Eagle Plain Basin, Yukon Territory, Canada

    Oil and Gas Resource Potential of Eagle Plain Basin, Yukon Territory, Canada

    GEOLOGICAL SURVEY OF CANADA OPEN FILE 7565 Oil and Gas Resource Potential of Eagle Plain Basin, Yukon, Canada P.K. Hannigan 2014 i GEOLOGICAL SURVEY OF CANADA OPEN FILE 7565 Oil and Gas Resource Potential of Eagle Plain Basin, Yukon, Canada P.K. Hannigan 1 1 (Geological Survey of Canada – Calgary, 3303-33rd Street, N.W., Calgary, Alberta) 2014 ©Her Majesty the Queen in Right of Canada 2014 doi:10.4095/293952 This publication is available for free download through GEOSCAN (http://geoscan.ess.nrcan.gc.ca/). Recommended citation Hannigan, P.K., 2014.Oil and gas resource potential of Eagle Plain Basin, Yukon, Canada; Geological Survey of Canada, Open File 7565, 181 p + 83 PDF files. doi:10.4095/293952 Publications in this series have not been edited; they are released as submitted by the author. ii Table of Contents ABSTRACT ................................................................................................................................................ 1 EXECUTIVE SUMMARY ............................................................................................................................. 1 INTRODUCTION ........................................................................................................................................ 3 GEOLOGICAL SETTING AND TECTONIC EVOLUTION .................................................................................. 4 PRECAMBRIAN BASEMENT ................................................................................................................................ 4 PROTEROZOIC
  • The Stratigraphic Relationship Between the Shuram Carbon Isotope

    The Stratigraphic Relationship Between the Shuram Carbon Isotope

    Chemical Geology 362 (2013) 250–272 Contents lists available at ScienceDirect Chemical Geology journal homepage: www.elsevier.com/locate/chemgeo The stratigraphic relationship between the Shuram carbon isotope excursion, the oxygenation of Neoproterozoic oceans, and the first appearance of the Ediacara biota and bilaterian trace fossils in northwestern Canada Francis A. Macdonald a,⁎, Justin V. Strauss a, Erik A. Sperling a, Galen P. Halverson b, Guy M. Narbonne c, David T. Johnston a, Marcus Kunzmann b, Daniel P. Schrag a, John A. Higgins d a Department of Earth and Planetary Sciences, Harvard University, 20 Oxford St., Cambridge, MA 02138, United States b Department of Earth and Planetary Sciences/GEOTOP, McGill University, Montreal, QC H3A 2T5, Canada c Department of Geological Sciences and Geological Engineering, Queen's University, Kingston, Ontario K7L 3N6, Canada d Princeton University, Guyot Hall, Princeton, NJ 08544, United States article info abstract Article history: A mechanistic understanding of relationships between global glaciation, a putative second rise in atmospher- Accepted 27 May 2013 ic oxygen, the Shuram carbon isotope excursion, and the appearance of Ediacaran-type fossil impressions and Available online 7 June 2013 bioturbation is dependent on the construction of accurate geological records through regional stratigraphic correlations. Here we integrate chemo-, litho-, and sequence-stratigraphy of fossiliferous Ediacaran strata Keywords: in northwestern Canada. These data demonstrate that the FAD of Ediacara-type fossil impressions in north- Ediacaran western Canada occur within a lowstand systems tract and above a major sequence boundary in the infor- Shuram Windermere mally named June beds, not in the early Ediacaran Sheepbed Formation from which they were previously δ13 Carbon-isotope reported.
  • Th TRILO the Back to the Past Museum Guide to TRILO BITES

    Th TRILO the Back to the Past Museum Guide to TRILO BITES

    With regard to human interest in fossils, trilobites may rank second only to dinosaurs. Having studied trilobites most of my life, the English version of The Back to the Past Museum Guide to TRILOBITES by Enrico Bonino and Carlo Kier is a pleasant treat. I am captivated by the abundant color images of more than 600 diverse species of trilobites, mostly from the authors’ own collections. Carlo Kier The Back to the Past Museum Guide to Specimens amply represent famous trilobite localities around the world and typify forms from most of the Enrico Bonino Enrico 250-million-year history of trilobites. Numerous specimens are masterpieces of modern professional preparation. Richard A. Robison Professor Emeritus University of Kansas TRILOBITES Enrico Bonino was born in the Province of Bergamo in 1966 and received his degree in Geology from the Depart- ment of Earth Sciences at the University of Genoa. He currently lives in Belgium where he works as a cartographer specialized in the use of satellite imaging and geographic information systems (GIS). His proficiency in the use of digital-image processing, a healthy dose of artistic talent, and a good knowledge of desktop publishing software have provided him with the skills he needed to create graphics, including dozens of posters and illustrations, for all of the displays at the Back to the Past Museum in Cancún. In addition to his passion for trilobites, Enrico is particularly inter- TRILOBITES ested in the life forms that developed during the Precambrian. Carlo Kier was born in Milan in 1961. He holds a degree in law and is currently the director of the Azul Hotel chain.
  • New Palaeoscolecidan Worms from the Lower Cambrian: Sirius Passet, Latham Shale and Kinzers Shale

    New Palaeoscolecidan Worms from the Lower Cambrian: Sirius Passet, Latham Shale and Kinzers Shale

    New palaeoscolecidan worms from the Lower Cambrian: Sirius Passet, Latham Shale and Kinzers Shale SIMON CONWAY MORRIS and JOHN S. PEEL Conway Morris, S. and Peel, J.S. 2010. New palaeoscolecidan worms from the Lower Cambrian: Sirius Passet, Latham Shale and Kinzers Shale. Acta Palaeontologica Polonica 55 (1): 141–156. Palaeoscolecidan worms are an important component of many Lower Palaeozoic marine assemblages, with notable oc− currences in a number of Burgess Shale−type Fossil−Lagerstätten. In addition to material from the lower Cambrian Kinzers Formation and Latham Shale, we also describe two new palaeoscolecidan taxa from the lower Cambrian Sirius Passet Fossil−Lagerstätte of North Greenland: Chalazoscolex pharkus gen. et sp. nov and Xystoscolex boreogyrus gen. et sp. nov. These palaeoscolecidans appear to be the oldest known (Cambrian Series 2, Stage 3) soft−bodied examples, being somewhat older than the diverse assemblages from the Chengjiang Fossil−Lagerstätte of China. In the Sirius Passet taxa the body is composed of a spinose introvert (or proboscis), trunk with ornamentation that includes regions bearing cuticu− lar ridges and sclerites, and a caudal zone with prominent circles of sclerites. The taxa are evidently quite closely related; generic differentiation is based on degree of trunk ornamentation, details of introvert structure and nature of the caudal re− gion. The worms were probably infaunal or semi−epifaunal; gut contents suggest that at least X. boreogyrus may have preyed on the arthropod Isoxys. Comparison with other palaeoscolecidans is relatively straightforward in terms of compa− rable examples in other Burgess Shale−type occurrences, but is much more tenuous with respect to the important record of isolated sclerites.
  • Buenellus Chilhoweensis N. Sp. from the Murray Shale (Lower Cambrian Chilhowee Group) of Tennessee, the Oldest Known Trilobite from the Iapetan Margin of Laurentia

    Buenellus Chilhoweensis N. Sp. from the Murray Shale (Lower Cambrian Chilhowee Group) of Tennessee, the Oldest Known Trilobite from the Iapetan Margin of Laurentia

    Journal of Paleontology, 92(3), 2018, p. 442–458 Copyright © 2018, The Paleontological Society. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/ licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. 0022-3360/18/0088-0906 doi: 10.1017/jpa.2017.155 Buenellus chilhoweensis n. sp. from the Murray Shale (lower Cambrian Chilhowee Group) of Tennessee, the oldest known trilobite from the Iapetan margin of Laurentia Mark Webster,1 and Steven J. Hageman2 1Department of the Geophysical Sciences, University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637 〈[email protected]〉 2Department of Geology, Appalachian State University, Boone, North Carolina 28608, USA 〈[email protected]〉 Abstract.—The Ediacaran to lower Cambrian Chilhowee Group of the southern and central Appalachians records the rift-to-drift transition of the newly formed Iapetan margin of Laurentia. Body fossils are rare within the Chilhowee Group, and correlations are based almost exclusively on lithological similarities. A critical review of previous work highlights the relatively weak biostratigraphic and radiometric age constraints on the various units within the succession. Herein, we document a newly discovered fossil-bearing locality within the Murray Shale (upper Chilhowee Group) on Chilhowee Mountain, eastern Tennessee, and formally describe a nevadioid trilobite, Buenellus chilhoweensis n. sp., from that site. This trilobite indicates that the Murray Shale is of Montezuman age (provisional Cambrian Stage 3), which is older than the Dyeran (provisional late Stage 3 to early Stage 4) age suggested by the historical (mis)identification of “Olenellus sp.” from within the unit as reported by workers more than a century ago.
  • A Problematical Trilobite from the Lower Cambrian of Freuchen Land, Central North Greenland

    A Problematical Trilobite from the Lower Cambrian of Freuchen Land, Central North Greenland

    A problematical trilobite from the Lower Cambrian of Freuchen Land, central North Greenland Philip D. Lane and Adrian W. A. Rushton A single specimen of a remarkable trilobite is described from the Early Cambrian Buen Formation of north-east Freuchen Land, central North Greenland. It is re­ ferred with doubt to Alacephalus Repina, 1960, as a new species A? davisi sp. nov. It possibly lacked eyes, which makes it one of, if not the, earliest non-agnostoid trilobite with this adaptation. Its thoracic segments have a unique morphology. In some respects the morphology resembles that of various trilobites adapted to low-energy benthic environments of low oxygenation; such trilobites tend to be widely distrib­ uted, and in agreement with this Alacephalus appears to be interprovincial. P. D. L., Department ofGeology, Vniversity ofKeele, Keele, Staffordshire ST5 5BG, V.K. A. W. A. R., British Geological Survey, Keyworth, Nottingham NG12 5GG, U.K. The trilobite described below was collected by Neil C. olenellid trilobite Buenellus higginsi Blaker, 1988 (Fam- ~ Davis from laminated, locally bioturbated, mudstones ily Nevadiidae) is associated with an abundant soft- in north-east Freuchen Land (Fig. l; Geological Survey bodied fauna (Conway Morris et al.. 1987; Conway of Greenland collection 319544) which are estimated to Morris & Peel, 1990; Peel, 1990), together with large be not more than 5 m from the top of the Buen Forma­ articulated sponges such as the demosponge Choia hin­ tion. This formation has been interpreted as a silic­ dei Rigby, 1986; the same kinds of sponges are associ­ ic1astic shelf deposit forming part of the sequence on the ated with the new trilobite in GGU collection 319544.
  • The Early Mesozoic Cordilleran Arc and Late Triassic Paleotopography: the Detrital Record in Upper Triassic Sedimentary Successions on and Off the Colorado Plateau

    The Early Mesozoic Cordilleran Arc and Late Triassic Paleotopography: the Detrital Record in Upper Triassic Sedimentary Successions on and Off the Colorado Plateau

    The Early Mesozoic Cordilleran arc and Late Triassic paleotopography: The detrital record in Upper Triassic sedimentary successions on and off the Colorado Plateau N.R. Riggs1, S.J. Reynolds2, P.J. Lindner1,*, E.R. Howell1,†, A.P. Barth3, W.G. Parker4, and J.D. Walker5 1School of Earth Sciences and Environmental Sustainability, Northern Arizona University, Flagstaff, Arizona 86011, USA 2School of Earth and Space Exploration, Arizona State University, Tempe, Arizona 85287-1404, USA 3Department of Earth Sciences, Indiana University–Purdue University Indianapolis, Indianapolis, Indiana 46202, USA 4Division of Resource Management, Petrifi ed Forest National Park, Petrifi ed Forest, Arizona 86028, USA 5Department of Geology, University of Kansas, Lawrence, Kansas 66045, USA ABSTRACT eroding into the stream systems that depos- of the record of magmatism is in backarc sedi- ited the three units. Streams diverged from mentary successions. Upper Triassic sandstones in diverse loca- a common source that maintained a rela- Unmetamorphosed Paleozoic sections tions in eastern California, southern Arizona, tively uniform magma composition over are exposed on the Colorado Plateau and in and on the Colorado Plateau (USA) yield time, as indicated by a narrow range of southern Arizona, and equivalent strata have detrital zircons that are remarkably similar in Th/U values, as well as tapping a somewhat long been recognized in deformed sections in age and geochemistry, leading to the hypoth- different source evidenced by a grouping eastern California and western Arizona, where esis that they are temporally related and in which Th/U ratios are lower. Once the they are overlain by strata of the Buckskin and were derived from similar sources.