DOCSLIB.ORG

Geochemistry of Coal–Bearing Permo−Triassic Strata in Allan Hills, South Victoria Land, Antarctica: Implications for Palaeoclimate

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Geochemistry of Coal–Bearing Permo−Triassic Strata in Allan Hills, South Victoria Land, Antarctica: Implications for Palaeoclimate The Palaeobotanist 67(2018): 89–97 0031–0174/2018 Geochemistry of coal–bearing Permo−Triassic strata in Allan Hills, South Victoria Land, Antarctica: Implications for palaeoclimate SUNDEEP K. PANDITA1*, N.S. SIDDAIAH2, RAJNI TEWARI3, SANKAR CHATTERJEE4 AND DEEPA AGNIHOTRI5 1Department of Geology, University of Jammu, Jammu 180 006, India. 2Department of Environmental Science, Jawahar Lal Nehru University, New Delhi 110 016, India. 3C–38, Alkapuri, Sector C, Aliganj, Lucknow 226 024, India. 4Texas Tech University, Lubbock, Texas, USA. 5Birbal Sahni Institute of Palaeosciences, 53 University Road, Lucknow 226 007, India. *Corresponding author: [email protected] (Received 09 February, 2018; revised version accepted 03 March, 2018) ABSTRACT Pandita SK, Siddaiah NS, Tewari R, Chatterjee S & Agnihotri D 2018. Geochemistry of coal–bearing Permo–Triassic strata in Allan Hills, South Victoria Land, Antarctica: Implications for palaeoclimate. The Palaeobotanist 67(1): 89–97. Major, trace and rare earth element (REE) geochemistry has been carried out in this paper to characterize source–rock weathering and climatic variability of the late Permian Weller Formation and the late Triassic Lashly Formation of Gondwana sequences which have yielded rich record of plant mega–and micro fossils associated with coal beds in post–glacial conditions in Allan Hills of South Victoria Land, Antarctica. The geochemistry suggests dominantly a felsic provenance with a volcanogenic input and role of weathering and hydrothermal alteration. The palaeoclimatic interpretation derived from geochemical analysis indicates warm, temperate and humid conditions during the late Permian, and warm and humid conditions during the late Triassic. Key–words—Geochemistry, Permian, Triassic, Allan Hills, Antarctica. ,Syu igkfM+;ka] nf{k.k foDVksfj;k Hkwfe] vaVkdZfVdk esa dks;yk&/kkjd ieksZ&Vªk;fld Lrjksa dk Hkw&jlk;ufoKku% iqjktyok;q fufgrkFkZ Laknhi ds- iafMrk] ,u-,l- fln~/kS;k] jtuh frokjh] 'kadj pSVthZ ,oa nhik vfXugks=kh lkjka'k xksaMokuk vuqØeksa ds foyafcr ifeZ;u oSYyj 'kSylewg ,oa foyafcr Vªkb,fld yS'kyh 'kSylewg dk lzksr 'kSy vi{k; ,oa tyok;oh ifjorZuh;rk dks vfHky{kf.kr djus ds fy, bl 'kks/k i=k esa izeq[k rRo] lw{eekf=kd ,oa nqyZHk i`Foh rRoksa ¼REE½ dk Hkw&jlk;ufoKku fd;k x;k gSA ftuls nf{k.k foDVksfj;k Hkwfe] vaVkdZfVdk dh ,Syu igkfM+;ksa esa fge;qxksRrj n'kkvksa esa dks;yk laLrjksa ls la?kfVr ikni LFkwy ,oa lw{e thok'eksa ds izpqj vfHkys[k feys gSaA Hkw&jlk;ufoKku izcyrk ls okWYdsukstsfud vkxr ds lkFk QsfYld mn~xe&LFky rFkk vi{k; o m".ktyh; ifjorZu dh Hkwfedk lq>krk gSA Hkw&jklk;fud fo'ys"k.k ls O;qRiUu iqjktyok;oh foospu foyafcr ifeZ;u ds nkSjku dks".k] 'khrks".k o vknZz fLFkfr;ka rFkk foyafcr Vªkb,fld ds nkSjku dks".k o vknZz fLFkfr;ka bafxr djrk gSA lwpd 'kCnµHkw&jlk;ufoKku] ifeZ;u] Vªkb,fld] ,Syu igkfM+;ka] vaVkdZfVdkA © Birbal Sahni Institute of Palaeosciences, India 90 THE PALAEOBOTANIST INTRODUCTION 1994; Roex et al., 1985; Zhao et al., 1997; Khare et al., 2009; Srivastava et al., 2013), and petrological (Roex et al., 1985; NTARCTICA, presently one of the world’s driest deserts Kumar et al., 2013) aspects. Aand totally inhospitable to plant life, was a part of the The late Permian Weller Formation and the late Triassic Gondwana Supercontinent during Permian and Triassic along Lashly Formation of Gondwana sequences in Allan Hills with other continents such as India, Australia, South America (latitude 76.72ºS, longitude 159.67ºE) of South Victoria Land, and South Africa. The melting of the late Carboniferous–Early Antarctica have yielded rich record of plant mega–and micro Permian ice sheet led to amelioration of climate subsequently fossils associated with coal beds in post–glacial conditions followed by a rapid evolution of the Glossopteris flora in the (Chatterjee et al., 2013; Ram–Awatar et al., 2014: Tewari Gondwana continents. Extensive cold–temperate swamps et al., 2015). The Weller Formation, which lies directly with thriving plant communities of Glossopteris and other over the early Permian glacial strata, records a change from allied plants formed thick coal seams in different Gondwana glacial to postglacial condition with the establishment of basins. The trunks of the trees that bore Glossopteris leaves polar forest (Tewari et al., 2015). Upward in the Gondwana are marked by growth rings, reflecting the effects of strong sequence, thick coal beds occur in swamp and meandering seasonality. At the end of the Permian, when the climate stream facies of Weller and Lashly formations, while they are became increasingly hot and dry with marked seasonality conspicuously absent in the intervening Feather Formation of rainfall, a new flora–the Dicroidium flora appeared in of channel deposits. Sedimentological (Retallack et al., the Gondwana continents. The Permo–Triassic transition 2005) and petrographic (Kumar et al., 2011) studies of these is an important time in the evolution of several groups of fossiliferous horizons exhibit microscopic charcoal remains, Gondwana plants, when Dicroidium flora gradually replaced which suggest ancient forest fire events, possibly caused by the Glossopteris flora. Antarctica, too, fostered dense forests continental volcanism (Kumar et al., 2013). The preservation of Glossopteris and Dicroidium floras during Permian and of carbonaceous material and the deposition of coal during Triassic, respectively. Permian and Triassic were probably related to climatic The vegetation of Antarctica is of evolutionary changes, including increase in temperature and humidity. significance since it encompasses not only early vascular Major, trace and rare earth element (REE) geochemistry land plants like bryophytes but also a number of higher plant has been found to be useful to characterize source–rock orders such as Sphenophyllales, Filicales, Pteridospermales, weathering and climatic variability from the terrestrial detritus Glossopteridales, Cordaitales Corystospermales, Cycadales of a basin (Nesbitt & Young, 1982; Cox et al., 1995; Basu, and Pinales. A plethora of information is available on the 1976; Quasim et al., 2017). Their records are influenced Permian (Plumstead, 1975; Rigby, 1969; Rigby & Schopf, by source rock lithologies, chemical weathering, sorting, 1969; Schopf, 1968, 1976; Kräusel, 1962; Maheshwari, sedimentation and post depositional diagenetic reactions 1972; Chatterjee et al., 1983; Gee, 1989; Pigg & Taylor, (McLennan et al., 1993). The distribution of these elements 1990, 1993; Smoot & Taylor, 1986; Taylor & Taylor, 1987; provides clues of the geological processes, provenance and Taylor et al., 1992; Retallack & Krull, 1999; Retallack et al., tectonic setting (McLennan et al., 1993; Cullers et al., 1988; 2005) and Triassic (Osborne & Taylor, 1989; Osborne et al., McLennan, 1989). The REE geochemistry has an added 2000; Bose et al., 1990 and references cited therein, Perovich advantage over major and trace elements to decipher the & Taylor, 1989; Delevoryas et al., 1992; Webb & Fielding, provenance, since the concentration of these elements is not 1993; Taylor, 1996; Taylor et al., 1994; Cantrill et al., 1995; affected during erosion, sedimentation and diagenesis and McLoughlin et al., 1997; Yao et al., 1995,1997; Phipps et al., thus represents a homogenized average source composition 1998; Axsmith et al., 2000; Rothwell et al., 2002; McManus (McLennan, 1989; Bhatia, 1985; Nance & Taylor, 1976). et al., 2002; Klavins et al., 2002, 2003, 2004; Hermans et al., This paper attempts to investigate the geochemistry 2007; Bomfleur & Kerp, 2010; Bomfleur et al., 2007, 2011; of two rock samples collected from the Permian Weller Escapa et al., 2011) megafloras of east and west, and central and Triassic Lashly formations to understand the source Transantarctic Mountains, Antarctica. Besides, several studies and composition of these rocks and their implication on have been carried out on palynological (Balme & Playford, palaeoclimate of the area. 1967; Kyle, 1977; Kyle & Schopf, 1982; Larson et al., 1990; Farabee et al., 1990; Lindstörm, 1996, 2005; Masood et al., GEOLOGICAL SETTING 1994; Askin, 1995; McLoughlin et al., 1997; Ram–Awatar et al., 2014), faunal (Hammer et al., 2004; Retallack et al., The Beacon Supergroup crops out along the length of 2005 and references cited therein), palaeofire (Kumar et al., the Transantarctic Mountains and was deposited in a retroarc 2011) geochemical and geophysical (Angino & Armitage, foreland basin (Collinson et al., 2006). The exposures of this 1963; Weiss et al., 1979; Saunders et al., 1980; Kurat et al. supergroup in the Allan Hills occur in the shape of a Y (Fig. PANDITA et al.—GEOCHEMISTRY OF COAL–BEARING PERMO−TRIASSIC STRATA IN ANTARCTICA 91 Fig. 1—Geological map of Allan Hills (marked by an arrow), South Victoria Land, central Transantarctic Mountains, Antarctica (modified after Kyle, 1977) showing the sample locations. 92 THE PALAEOBOTANIST 1) and are divided into two units: the lower Victoria Group 4–5 drops of polyvinyl alcohol as binding agent (Stork et al., of mainly fluvial siliciclastics, and the upper Ferrar Group 1987; Saini et al., 2002). The pellets were analyzed for the of volcanic origin (Ballance, 1977; Chatterjee et al., 1983). major and trace elemental abundance by standard Wavelength The stratigraphy of Allan Hills has been discussed by Dispersive X–ray Flourescence Spectrometer (Siemens SRS– Gunn and Warren (1962), Borns and Hall (1969), Barrett et 3000) at Wadia Institute of Himalayan Geology, Dehradun al. (1971), Barrett and Kohn (1975), Ballance (1977),
Load more

Recommended publications
  • The Possible Pollen Cone of the Late Triassic Conifer Heidiphyllum/Telemachus (Voltziales) from Antarctica
    KU ScholarWorks | http://kuscholarworks.ku.edu Please share your stories about how Open Access to this article benefits you. The Possible Pollen Cone of the Late Triassic Conifer Heidiphyllum/ Telemachus (Voltziales) From Antarctica by Benjamin Bomfleur, Rudolph Serbet, Edith L. Taylor, and Thomas N. Taylor 2011 This is the published version of the article, made available with the permission of the publisher. The original published version can be found at the link below. Bomfleur, B., Serbet, R., Taylor, E., and Taylor, N. 2011. The Possible Pollen Cone of the Late Triassic Conifer Heidiphyllum/Telemachus (Voltziales) From Antarctica. Antarctic Science 23(4): 379-385. Published version: http://dx.doi.org/10.1017/S0954102011000241 Terms of Use: http://www2.ku.edu/~scholar/docs/license.shtml This work has been made available by the University of Kansas Libraries’ Office of Scholarly Communication and Copyright. Antarctic Science 23(4), 379–385 (2011) & Antarctic Science Ltd 2011 doi:10.1017/S0954102011000241 The possible pollen cone of the Late Triassic conifer Heidiphyllum/Telemachus (Voltziales) from Antarctica BENJAMIN BOMFLEUR, RUDOLPH SERBET, EDITH L. TAYLOR and THOMAS N. TAYLOR Division of Paleobotany at the Department of Ecology and Evolutionary Biology, and Natural History Museum and Biodiversity Institute, University of Kansas, Lawrence, KS 66045, USA bbomfl[email protected] Abstract: Fossil leaves of the Voltziales, an ancestral group of conifers, rank among the most common plant fossils in the Triassic of Gondwana. Even though the foliage taxon Heidiphyllum has been known for more than 150 years, our knowledge of the reproductive organs of these conifers still remains very incomplete. Seed cones assigned to Telemachus have become increasingly well understood in recent decades, but the pollen cones belonging to these Mesozoic conifers are rare.
    [Show full text]
  • Debris Avalanche Deposits Associated with Large Igneous Province Volcanism: an Example from the Mawson Formation, Central Allan Hills, Antarctica
    The following document is a pre-print version of: Reubi, O., Ross, P.-S. et White, J.D.L. (2005) Debris avalanche deposits associated with Large Igneous province volcanism: an example from the Mawson Formation, Central Allan Hills, Antarctica. Geological Society of America Bulletin 117: 1615–1628 Debris avalanche deposits associated with large igneous province volcanism: an example from the Mawson Formation, central Allan Hills, Antarctica O. Reubi 1,2,3 , P-S. Ross 1,2,4 and J.D L. White 1 1. Department of Geology, University of Otago, PO Box 56, Dunedin, New Zealand. 2. These authors contributed equally to this work. 3. Now at : Institut de Minéralogie et Pétrographie, Section des Sciences de la Terre, Université de Lausanne, BFSH-2, CH-1015 Lausanne, Switzerland. 4. Corresponding author. ABSTRACT An up to 180 m-thick debris avalanche deposit related to Ferrar large igneous province magmatism is observed at central Allan Hills, Antarctica. This Jurassic debris avalanche deposit forms the lower part (member m 1) of the Mawson Formation and is overlain by thick volcaniclastic layers containing a mixture of basaltic and sedimentary debris (member m 2). The m 1 deposit consists of a chaotic assemblage of breccia panels and megablocks up to 80 m across. In contrast to m 2, it is composed essentially of sedimentary material derived from the underlying Beacon Supergroup. The observed structures and textures suggest that the breccias in m 1 were mostly produced by progressive fragmentation of megablocks during transport but also to a lesser extent by disruption and ingestion of the substrate by the moving debris avalanche.
    [Show full text]
  • Curriculum Vitae
    1 CURRICULUM VITAE NAME: SANKAR CHATTERJEE ADDRESS: Department of Geosciences Museum of Texas Tech University, MS/Box 43191 Lubbock, TX 79409-3191, USA. Phone: (806) 742-1986 Fax: (806) 742-1136 E-mail: [email protected] Website: http://www.gesc.ttu.edu/Fac_pages/chatterjee/ PERSONAL INFORMATION: Born: May 28, 1943, Calcutta, India. U. S. Citizen Married, two boys. PRESENT POSITION: Paul Whitfield Horn Professor of Geosciences and Museum Science; Curator of Paleontology and Director, Antarctic Research Center, Museum of Texas Tech University. EDUCATION: • B. S. in Geology Honors, First in First Class, Jadavpur University, 1962. • M. S. in Applied Geology, First in First Class, Jadavpur University, 1964. • Predoctoral Fellow, London University, 1967-68. • Ph. D. in Geology, Calcutta University, Calcutta, India, 1970. • Postdoctoral Fellow, Smithsonian Institution, 1977-78. ACADEMIC POSITIONS: • Honorary Professor, Indian Institute of Science Education and Research, Calcutta, India, 2010 – Present. • Visiting Professor, Indian Statistical Institute, Calcutta, India, 1996 - Present. • Paul Whitfield Horn Professor & Curator of Paleontology, Texas Tech University, 1994 - Present. • Visiting Professor, Tübingen University, Germany, summer, 1992. • Visiting Professor, Tübingen University, Germany, summer, 1991. • Professor & Curator of Paleontology, Texas Tech University, 1987-1994. • Associate Professor & Curator, Texas Tech University, 1984-87. • Assistant Professor & Curator of Paleontology, Texas Tech University, 1979-84. • Assistant
    [Show full text]
  • Xxvi Jornadas...Qxd
    AMEGHINIANA Revista de la Asociación Paleontológica Argentina RESÚMENES TOMO 46 Número 4 BUENOS AIRES REPÚBLICA ARGENTINA 2009 Se deja constancia que el presente suplemento se halla desprovisto de validez para propósitos nomenclaturales Disclaimer: this supplement is not deemed to be valid for nomenclatural purposes El Comité Editor de la Asociación Paleontológica Argentina deja constancia que solamente se incluyen en este Suplemento los resúmenes enviados por los organizadores de las diferentes reuniones. AMEGHINIANA 46 (4) Suplemento, 2009-RESÚMENES XXIV JORNADAS ARGENTINAS DE PALEONTOLOGÍA DE VERTEBRADOS RESÚMENES 4 al 7 de mayo de 2009 Museo de Historia Natural de San Rafael (MHNSR), San Rafael, Mendoza COMISIÓN ORGANIZADORA Presidente Marcelo S. de la Fuente (MHNSR) Secretarias Analía Forasiepi (MHNSR) Juliana Sterli (MHNSR) Vocales Miriam Ayala (MHNSR) René Biglione (DGE-Mendoza) Sergio Dieguez (CNEA) Gladys García (Universidad Champagnat) Miguel Giardina (MHNSR) Adolfo Gil (MHNSR) Gustavo Neme (MHNSR) Clara Otaola (MHNSR) Nuria Sugrañes (MHNSR) Financiado por ANPCyT, CONICET y Fondo Provincial de la Cultura de la Pcia. de Mendoza. Auspiciado por Asociación Paleontológica Argentina, Museo de Historia Natural de San Rafael y Municipalidad de San Rafael (Mendoza). AMEGHINIANA 46 (4) Sumplemento, 2009-RESÚMENES 4R CONFERENCIAS Origen de la ictiofauna marina y continental de América del Sur Austral A.L. CIONE1 La ictiofauna neotropical continental es la más rica en especies del mundo. Su mayor riqueza se localiza en las áreas intertropi- cales, un paralelo de lo que sucede con otros organismos. Se calcula que pueden existir 8.000 especies de peces continentales, un cuarto de la totalidad de los conocidos en todo el mundo en ambiente marino o continental.
    [Show full text]
  • Geological Evolution of the Coombs-Allan Hills Area, Ferrar Large Igneous Province, Antarctica
    The following document is a pre-print version of: Ross, P.-S., White, J.D.L. et McClintock, M. (2008) Geological evolution of the Coombs-Allan Hills area, Ferrar large igneous province, Antarctica: debris avalanches, mafic pyroclastic density currents, phreatocauldrons. Journal of Volcanology and Geothermal Research 172: 38-60 Geological evolution of the Coombs-Allan Hills area, Ferrar large igneous province, Antarctica: debris avalanches, mafic pyroclastic density currents, phreatocauldrons… Pierre-Simon Ross 1, James D.L. White, and Murray McClintock Department of Geology, University of Otago, PO Box 56, Dunedin, New Zealand 1. Corresponding author Abstract The Jurassic Ferrar large igneous province of Antarctica comprises igneous intrusions, flood lavas, and mafic volcaniclastic deposits (now lithified). The latter rocks are particularly diverse and well-exposed in the Coombs-Allan Hills area of South Victoria Land, where they are assigned to the Mawson Formation. In this paper we use these rocks in conjunction with the pre-Ferrar sedimentary rocks (Beacon Supergroup) and the lavas themselves (Kirkpatrick Basalt) to reconstruct the geomorphological and geological evolution of the landscape. In the Early Jurassic, the surface of the region was an alluvial plain, with perhaps 1 km of mostly continental siliciclastic sediments underlying it. After the fall of silicic ash from an unknown but probably distal source, mafic magmatism of the Ferrar province began. The oldest record of this event at Allan Hills is a ≤180 m-thick debris avalanche deposit (member m 1 of the Mawson Formation) which contains globular domains of mafic igneous rock. These domains are inferred to represent dismembered Ferrar intrusions emplaced in the source area of the debris avalanche; shallow emplacement of Ferrar magmas caused a slope failure that mobilized the uppermost Beacon Supergroup, and the silicic ash deposits, into a pre-existing valley or basin.
    [Show full text]
  • Geology.Gsapubs.Org on June 10, 2010
    Downloaded from geology.gsapubs.org on June 10, 2010 Geology Search for evidence of impact at the Permian-Triassic boundary in Antarctica and Australia: Comment and Reply John L. Isbell, Rosemary A. Askin and Gregory J. Retallack Geology 1999;27;859-860 doi: 10.1130/0091-7613(1999)027<0859:SFEOIA>2.3.CO;2 Email alerting services click www.gsapubs.org/cgi/alerts to receive free e-mail alerts when new articles cite this article Subscribe click www.gsapubs.org/subscriptions/ to subscribe to Geology Permission request click http://www.geosociety.org/pubs/copyrt.htm#gsa to contact GSA Copyright not claimed on content prepared wholly by U.S. government employees within scope of their employment. Individual scientists are hereby granted permission, without fees or further requests to GSA, to use a single figure, a single table, and/or a brief paragraph of text in subsequent works and to make unlimited copies of items in GSA's journals for noncommercial use in classrooms to further education and science. This file may not be posted to any Web site, but authors may post the abstracts only of their articles on their own or their organization's Web site providing the posting includes a reference to the article's full citation. GSA provides this and other forums for the presentation of diverse opinions and positions by scientists worldwide, regardless of their race, citizenship, gender, religion, or political viewpoint. Opinions presented in this publication do not reflect official positions of the Society. Notes Geological Society of America Downloaded from geology.gsapubs.org on June 10, 2010 Low-latitude sea-surface temperatures for the mid-Cretaceous and the evolution of planktic foraminifera: Comment and Reply COMMENT simplex and Hedbergella delrioensis occur in the same range as the keeled forms Praeglobotruncana delrioensis, Rotalipora brotzeni, Planomalina G.
    [Show full text]
  • Permian Extinction Event in Australia
    PALAIOS, 2020, v. 35, 342–357 Research Article DOI: http://dx.doi.org/10.2110/palo.2020.007 DWELLING IN THE DEAD ZONE—VERTEBRATE BURROWS IMMEDIATELY SUCCEEDING THE END- PERMIAN EXTINCTION EVENT IN AUSTRALIA 1 1 1 2 3 3 STEPHEN MCLOUGHLIN, CHRIS MAYS, VIVI VAJDA, MALCOLM BOCKING, TRACY D. FRANK, AND CHRISTOPHER R. FIELDING 1Swedish Museum of Natural History, Svante Arrhenius v. 9, SE-104 05, Stockholm, Sweden 2Bocking Associates, 8 Tahlee Close, Castle Hill, NSW, Australia 3Department of Earth and Atmospheric Sciences, University of Nebraska-Lincoln, 126 Bessey Hall, Lincoln, NE 68588-0340, USA email: [email protected] ABSTRACT: A distinctive burrow form, Reniformichnus australis n. isp., is described from strata immediately overlying and transecting the end-Permian extinction (EPE) horizon in the Sydney Basin, eastern Australia. Although a unique excavator cannot be identified, these burrows were probably produced by small cynodonts based on comparisons with burrows elsewhere that contain body fossils of the tracemakers. The primary host strata are devoid of plant remains apart from wood and charcoal fragments, sparse fungal spores, and rare invertebrate traces indicative of a very simplified terrestrial ecosystem characterizing a ‘dead zone’ in the aftermath of the EPE. The high-paleolatitude (~ 65–758S) setting of the Sydney Basin, together with its higher paleoprecipitation levels and less favorable preservational potential, is reflected by a lower diversity of vertebrate fossil burrows and body fossils compared with coeval continental interior deposits of the mid-paleolatitude Karoo Basin, South Africa. Nevertheless, these burrows reveal the survivorship of small tetrapods in considerable numbers in the Sydney Basin immediately following the EPE.
    [Show full text]
  • History of Oligocene Erosion, Uplift and Unroofing of the Transantarctic
    History of Oligocene Erosion, Uplift and Unroofing of the Transantarctic Mountains Deduced from Sandstone Detrital Modes in CRP-3 Drillcore, Victoria Land Basin, Antarctica J.L. SMRLI~II~ Brilish Antarctic Survey. Natural Environment Research Council. l-Iisli Cross, Madinglcy Road - Cambrklgc CB3 OET - UK ([email protected]) Received 26 October 2000: acc~~ptc~/in revised form 23 April 2001 Abstract - Detrital modes determined on 68 sandstone samplcs from CRP-3 drillcore indicate a continuation of the dynamic history of uplift-rclatcd erosion and unroofing previously documented in CRP-l and CRP-212A. Thc source area is identified very strongly with the Transantarctic Mountains (TAM) Dry Valleys block in southern Victoria Land. Initial unroofing of the TAM comprised removal of much of a former capping sequence of Jurassic Kirkpatrick basalts, which preceded the formation of the Victoria Land Basin. Erosion of Beacon Supergroup outcrops took place during progressive uplift of the TAM in the Oligocene. Earliest CRP-3 Oligocene samples above 788 metres below the sea floor (mbsf) were sourced overwhelmingly in Beacon Supergroup strata, including a recognisable contribution from Triassic volcanogenic Lashly Formation sandstones (uppermost Victoria Group). Moving up-section, by 500 mbsf, the CRP-3 samples are depauperate quartz arenites dominantly derived from the quartzose Devonian Taylor Group. Between c. 500 and 450 mbsf, the modal parameters show a distinctive change indicating that small outcrops of basement granitoids and metamorphic rocks were also being eroded along with the remaining Beacon (mainly Taylor Group) sequence. Apart from enigmatic fluctuations in modal indices above 450 mbsf. similar to those displayed by samples in CRP-2/2A, the CRP-3 modes are essentially constant (within a broad data scatter) to the top of CRP-3.
    [Show full text]
  • Triassic Floras of Antarctica: Plant Diversity and Distribution in High Paleolatitude Communities
    PALAIOS, 2011, v. 26, p. 522–544 Research Article DOI: 10.2110/palo.2010.p10-122r TRIASSIC FLORAS OF ANTARCTICA: PLANT DIVERSITY AND DISTRIBUTION IN HIGH PALEOLATITUDE COMMUNITIES IGNACIO H. ESCAPA,1,2* EDITH L. TAYLOR,1 RUBE´ NCU´ NEO,2 BENJAMIN BOMFLEUR,1,3 JULIE BERGENE,1 RUDOLPH SERBET,1 and THOMAS N. TAYLOR 1 1Department of Ecology and Evolutionary Biology, and Natural History Museum and Biodiversity Institute, University of Kansas, Lawrence 66045-7534, USA, [email protected], [email protected], [email protected], [email protected], [email protected]; 2CONICET—Museo Paleontolo´gico Egidio Feruglio, Trelew, Chubut, 9100, Argentina, [email protected]; 3Forschungsstelle fu¨r Pala¨obotanik am Institut fu¨r Geologie und Pala¨ontologie, Westfa¨lische Wilhelms-Universita¨t Mu¨nster, Hindenburgplatz 57, D-48143 Mu¨nster, Germany, [email protected] ABSTRACT number of Antarctic plant fossils during his career. His collection—now at the University of Kansas—includes plants preserved as impressions Continental Triassic sequences in Antarctica are among the most and compressions, palynological samples, and silicified wood from continuous and best represented in Gondwana. Triassic fossil plants have numerous sites, including southern and northern Victoria Land (SVL, been collected sporadically from Antarctica since the beginning of the NVL) and the CTM. twentieth century, but our knowledge of the vegetation during this time Certainly one of the most significant contributions of Schopf’s has dramatically increased during the last three decades. Here we review fieldwork in Antarctica was the discovery of permineralized peat from the fossil record of Triassic plants as representatives of natural groups two sites in the CTM (Schopf, 1970, 1978).
    [Show full text]
  • Under Pressure? Epicormic Shoots and Traumatic Growth Zones in High-Latitude Triassic Trees from East Antarctica
    Annals of Botany 121: 681–689, 2018 doi:10.1093/aob/mcx199, available online at www.academic.oup.com/aob Under pressure? Epicormic shoots and traumatic growth zones in high-latitude Triassic trees from East Antarctica Anne-Laure Decombeix1,2,*, Rudolph Serbet2 and Edith L. Taylor2 1CNRS and Université Montpellier 2, UMR AMAP, F-34000 Montpellier, France and 2Department of Ecology and Evolutionary Biology, and Natural History Museum and Biodiversity Institute, University of Kansas, Lawrence, KS 66045–7600, USA Downloaded from https://academic.oup.com/aob/article/121/4/681/4791876 by guest on 29 September 2021 *For correspondence. E-mail: [email protected] Received: 25 September 2017 Returned for revision: 14 November 2017 Editorial decision: 29 November 2017 Accepted: 5 December 2017 Published electronically 6 January 2018 • Background and Aims Investigating the biology of trees that were growing at high latitudes during warmer geological periods is key to understanding the functioning of both past and future forest ecosystems. The aim of this study is to report the first co-occurrence of epicormic shoots and traumatic growth zones in fossil trees from the Triassic of Antarctica and to discuss their biological and environmental implications. • Methods Permineralized woods bearing scars of epicormic shoots were collected from the Triassic Fremouw Formation in Gordon Valley, Central Transantarctic Mountains, Antarctica in 2010. Samples from different portions of three specimens were prepared using standard thin section and hydrofluoric (HF) acid peel techniques, and anatomical details were studied in transmitted light. • Key Results The fossil woods represent the outer part of trunks, with at least 40 growth rings that are 0.2–4.8 mm in width.
    [Show full text]
  • A Late Triassic Flora from the Allan Hills, Southern Victoria Land
    A Late Triassic flora AF from the Allan Hills, southern Victoria Land EDITH L. TAYLOR, THOMAS N. TAYLOR, BRIGITTE MEYER-BERTHAUD, and JOHN L. ISBELL Department of Plant Biology and Byrd Polar Research Center 4 , Ohio State University 4 I 4 Columbus, Ohio 43210 N. RUBEN CUNEO Museo Argentino de Ciencias Naturales "B. Rivadavia" Buenos Aires, Argentina Figure 1. Flattened cupule of a seed tern. (Bar scale = 1 centimeter.) In this article, we describe the occurrence of a well-preserved Late Triassic flora from the Allan Hills, southern Victoria Land. The plants are preserved as impression/compressions in gray, fine-grained siltstones that outcrop along the western side of ternodal distances ranging from 2.0 to 3.0 millimeters. Each the eastern arm of the Allan Hills. In some instances, cuticles leaf is 3.0 to 4.0 millimeters long and approximately 1.0 mil- are present. Collections were made from three different ho- limeter wide. A single ginkgophyte leaf was also found at this rizons during the 1989-1990 austral summer. The two upper level. Reproductive organs include numerous, isolated seeds, horizons are within Member C of the Lashly Formation and one cone about 3.0 centimeters long and two other slightly the third collection comes from siltstone lenses on a sandstone larger cones with scales of the Rissikia type (Townrow 1967b). platform within Member B of the Lashly. Plant level 2. The plants occur in a siltstone lens approxi- Plant level 1. The largest collection of megafossils occurs at mately 2 meters below level 1, with the most common element this level in a unit that varies from approximately 20 centi- being Dicroidium cf.
    [Show full text]
  • The Permian–Triassic Boundary in Antarctica G.J
    Antarctic Science 17 (2), 241–258 (2005) © Antarctic Science Ltd Printed in the UK DOI: 10.1017/S0954102005002658 The Permian–Triassic boundary in Antarctica G.J. RETALLACK1*, A.H. JAHREN2, N.D. SHELDON1,3, R. CHAKRABARTI4, C.A. METZGER1 and R.M.H. SMITH5 1Department of Geological Sciences, University of Oregon, Eugene, OR 97403, USA 2Department of Earth and Planetary Sciences, Johns Hopkins University, 34th and N. Charles Streets, Baltimore, MD 21218, USA 3current address: Geology Department, Royal Holloway University of London, Egham TW20 OEX, UK 4Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627, USA 5Department of Earth Sciences, South African Museum, PO Box 61, Cape Town 8000, South Africa *[email protected] Abstract: The Permian ended with the largest of known mass extinctions in the history of life. This signal event has been difficult to recognize in Antarctic non-marine rocks, because the boundary with the Triassic is defined by marine fossils at a stratotype section in China. Late Permian leaves (Glossopteris) and roots Vertebraria), and Early Triassic leaves (Dicroidium) and vertebrates (Lystrosaurus) roughly constrain the Permian–Triassic boundary in Antarctica. Here we locate the boundary in Antarctica more precisely using carbon isotope chemostratigraphy and total organic carbon analyses in six measured sections from Allan Hills, Shapeless Mountain, Mount Crean, Portal Mountain, Coalsack Bluff and Graphite Peak. Palaeosols and root traces also are useful for recognizing the Permian–Triassic boundary because there was a complete turnover in terrestrial ecosystems and their soils. A distinctive kind of palaeosol with berthierine nodules, the Dolores pedotype, is restricted to Early Triassic rocks.
    [Show full text]