DOCSLIB.ORG

U-Pb Geochronologic Evidence for the Evolution of the Gondwanan Margin of the North-Central Andes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
U-Pb Geochronologic Evidence for the Evolution of the Gondwanan Margin of the North-Central Andes U-Pb geochronologic evidence for the evolution of the Gondwanan margin of the north-central Andes David M. Chew† Urs Schaltegger Department of Mineralogy, University of Geneva, Rue des Maraîchers 13, 1205 Geneva, Switzerland Jan Košler Department of Earth Science, University of Bergen, Allegaten 41, N-5007 Bergen, Norway Martin J. Whitehouse Laboratory for Isotope Geology, Swedish Museum of Natural History, S-104 05 Stockholm, Sweden Marcus Gutjahr Institute for Isotope Geology and Mineral Resources, ETH-Zentrum, Clausiusstrasse 25, CH-8092 Zürich, Switzerland Richard A. Spikings Aleksandar Miškovi´c Department of Mineralogy, University of Geneva, Rue des Maraîchers 13, 1205 Geneva, Switzerland ABSTRACT zircon overgrowths from amphibolite-facies limited because they are either obscured by later schists, which reveals metamorphic events tectonic events along the convergent margin or We investigated the Neoproterozoic–early at ca. 478 and ca. 312 Ma and refutes the buried by the ubiquitous volcanic cover. Paleozoic evolution of the Gondwanan mar- previously assumed Neoproterozoic age for This problem is particularly acute in the gin of the north-central Andes by employing orogeny in the Peruvian Eastern Cordillera. north-central Andes, where Precambrian base- U-Pb zircon geochronology in the Eastern The presence of an Ordovician magmatic ment is not exposed for over 2000 km along Cordilleras of Peru and Ecuador using a and metamorphic belt in the north-central strike, from 15°S in Peru to 2°S in Colombia. combination of laser-ablation–inductively Andes demonstrates that Famatinian meta- This corresponds to the distance between the coupled plasma–mass spectrometry detrital morphism and subduction-related mag- northern extent of the Arequipa-Antofalla base- zircon analysis and dating of syn- and post- matism were continuous from Patagonia ment (Fig. 1), a Proterozoic crustal block that tectonic intrusive rocks by thermal ionization through northern Argentina to Venezuela. experienced 0.9–1.2 Ga Grenville metamor- mass spectrometry and ion microprobe. The The evolution of this extremely long Ordo- phism (Loewy et al., 2004; Wasteneys et al., majority of detrital zircon samples exhibits vician active margin on western Gondwana 1995), and the southernmost basement expo- prominent peaks in the ranges 0.45–0.65 Ga is very similar to the Taconic orogenic cycle sures in Colombia, the Proterozoic Garzón and 0.9–1.3 Ga, with minimal older detri- of the eastern margin of Laurentia, and our inlier (Restrepo-Pace et al., 1997; Cordani et al., tus from the Amazonian craton. These data fi ndings support models that show these two 2005). This zone is also characterized by sub- imply that the Famatinian-Pampean and active margins facing each other during the stantial development of Andean foreland sedi- Grenville (= Sunsas) orogenies were available Ordovician. ments to the east, so that the basement geology to supply detritus to the Paleozoic sequences peripheral to the orogen is not known with any of the north-central Andes, and these oro- Keywords: Gondwana, Andes, Peru, geochro- degree of certainty. genic belts are interpreted to be either buried nology, zircon, Paleozoic. However, in the Eastern Cordilleras of Peru underneath the present-day Andean chain and Ecuador, Paleozoic metasedimentary or adjacent foreland sediments. There is evi- INTRODUCTION sequences are well exposed. Most of these dence of a subduction-related magmatic belt sequences, including the Marañon Complex in (474–442 Ma) in the Eastern Cordillera of The Andes represent the locus of continued Peru (Fig. 2) and the Isimanchi and Chiguinda Peru and regional orogenic events that pre- plate convergence through much of the Pha- Units of the Cordillera Real in Ecuador and postdate this phase of magmatism. These nerozoic. Whereas Andean deformation and (Fig. 2), are considered to be autochthonous are confi rmed by ion-microprobe dating of magmatism have been extensively studied, the with respect to the Gondwanan margin (Hae- early evolution of much of the proto-Andean berlin, 2002; Pratt et al., 2005). Hence, their †Present address: Department of Geology, Trinity margin remains poorly understood. The main heavy mineral assemblages, and, in particular, College Dublin, Dublin 2, Ireland; e-mail: chewd@ reason is because exposures of pre-Andean their detrital zircon populations, should reveal tcd.ie. basement rocks are in many places extremely information regarding their source areas—in GSA Bulletin; May/June 2007; v. 119; no. 5/6; p. 697–711; doi: 10.1130/B26080.1; 8 fi gures; Data Repository item 2007110. For permission to copy, contact [email protected] 697 © 2007 Geological Society of America Chew et al. this case the Gondwanan margin of the north- 80° W 60° W 40° W Garzón Neoproterozoic ern Andes. Furthermore, granitic magmas that tectonic provinces intrude these sequences can carry inherited MI in Amazonian craton Santander zircon, which will also provide source infor- CA mation, particularly with respect to deeper 0° VT MI São Luis Craton crustal levels that would otherwise be impos- RNJ sible to sample. The age and number of orogenic episodes Fig. Brasília CA belt in these Paleozoic sequences are poorly con- 2 VT strained, especially in the high-grade meta- RNJ Figure 1. Map of South morphic sequences of the Eastern Cordillera of SF America illustrating the Peru. It is thus entirely unknown how this region SS RO major tectonic provinces relates to other zones along the proto-Andean Arequipa and the ages of their most margin of Gondwana, where the Paleozoic Antofalla recent metamorphic events geological history is signifi cantly better under- Basement20°S São Francisco (adapted from Cordani et stood (e.g., northern Argentina and Venezuela- Sierra Craton al., 2000). Precambrian Colombia; see Ramos and Aleman, 2000, for a Rio (SF) Pampeanas and Paleozoic inliers in the review). However, the metasedimentary rocks de la Central Famatina Plata Amazonian Andean belt are shown in of the Peruvian Eastern Cordillera are intruded CA Arc Craton Province black and light gray, respec- by several phases of Paleozoic magmatism that (>2.3 Ga) Precordillera tively. Maroni-Itacaiúnas can be temporally related to the various regional Terrane MI orogenic episodes. The combination of precise Province (2.2 - 1.9 Ga) 40° S U-Pb zircon geochronology from these intrusive VT Ventuari-Tapajós Province (2 - 1. 8 Ga) rocks with the provenance information described Precambrian basement RNJ Rio Negro-Jurena already thus provides new constraints on both Province (1.8 - 1.5 Ga) the timing of orogeny and the paleogeography Andean Belt RO Rondonia-San Ignacio of the Gondwanan margin of the north-central Paleozoic N Province (1.5 - 1.3 Ga) Andes during the Paleozoic. sequences SS Sunsás referred to in text Province (1.3 - 1.0 Ga) REGIONAL GEOLOGY The Andes of Ecuador can be subdivided into a Western Cordillera, consisting of accreted gneisses of the Arequipa-Antofalla basement (which has apparent vertical displacements of Late Cretaceous oceanic rocks, and an Eastern (Figs. 1 and 2). many kilometers) is believed to be Miocene– Cordillera (the Cordillera Real), which consists Pliocene in age (Pratt et al., 2005). of Mesozoic plutons emplaced into probable Cordillera Real of Ecuador Paleozoic metamorphic pelites and volcanics Eastern Cordillera of Peru (Fig. 2). The southern boundary of the accreted There is very little age control on the Paleo- oceanic rocks is marked by the Gulf of Guaya- zoic metamorphic pelites and volcanics of the Existing age constraints on the timing of quil (Fig. 2). The metamorphic belts of the Cor- Cordillera Real of Ecuador, and opinion dif- deposition and metamorphism of metasedimen- dillera Real continue into northern Peru (Fig. 2), fers as to whether the majority of the units are tary schists and gneisses of the Eastern Cordi- where there is a marked change in the orienta- allochthonous (e.g., Litherland et al., 1994) lle ra (the Marañon Complex) are very poor. Nd tion of the Andean chain at ~6°S, termed the or autochthonous terranes (e.g., Pratt et al., model ages cluster between 1.5 and 2 Ga (Mac- Huancabamba defl ection. 2005). The uncertainty relates to the tectonic farlane, 1999), while a poorly defi ned Neopro- South of the Huancabamba defl ection, the signifi cance attached to north-south faults that terozoic age has been assigned to the metamor- Peruvian Andes are composed of a Western run along the spine of the Cordillera Real. phism based on bulk, unabraded U-Pb zircon Cordillera, consisting of Mesozoic sediments The model of Litherland et al. (1994) invokes data (ca. 630–610 Ma lower intercepts) from intruded by a Mesozoic arc (the Coastal Batho- these faults as major Mesozoic terrane-bound- granulitic gneisses in central Peru (Dalmayrac et lith) with younger Tertiary volcanics and local- ing sutures that separate a series of suspect ter- al., 1980). Recent research has demonstrated the ized plutons (the Cordillera Blanca), and an ranes. These are illustrated on Figure 2 and are, presence of an Early Ordovician (484 ± 12 Ma) Eastern Cordillera, consisting of a sequence from west to east: Guamote (continental), Alao metamorphic event in the Marañon Complex of metasedimentary schists and gneisses (the (island arc), Loja (continental), Salado (island (Cardona et al., 2006). Marañon Complex) intruded chiefl y by Carbon- arc), and Amazonic (continental craton). The Existing constraints on the timing of mag- iferous and Permian-Triassic plutons (Fig. 2). model of Pratt et
Load more

Recommended publications
  • Two Contrasting Phanerozoic Orogenic Systems Revealed by Hafnium Isotope Data William J
    ARTICLES PUBLISHED ONLINE: 17 APRIL 2011 | DOI: 10.1038/NGEO1127 Two contrasting Phanerozoic orogenic systems revealed by hafnium isotope data William J. Collins1*(, Elena A. Belousova2, Anthony I. S. Kemp1 and J. Brendan Murphy3 Two fundamentally different orogenic systems have existed on Earth throughout the Phanerozoic. Circum-Pacific accretionary orogens are the external orogenic system formed around the Pacific rim, where oceanic lithosphere semicontinuously subducts beneath continental lithosphere. In contrast, the internal orogenic system is found in Europe and Asia as the collage of collisional mountain belts, formed during the collision between continental crustal fragments. External orogenic systems form at the boundary of large underlying mantle convection cells, whereas internal orogens form within one supercell. Here we present a compilation of hafnium isotope data from zircon minerals collected from orogens worldwide. We find that the range of hafnium isotope signatures for the external orogenic system narrows and trends towards more radiogenic compositions since 550 Myr ago. By contrast, the range of signatures from the internal orogenic system broadens since 550 Myr ago. We suggest that for the external system, the lower crust and lithospheric mantle beneath the overriding continent is removed during subduction and replaced by newly formed crust, which generates the radiogenic hafnium signature when remelted. For the internal orogenic system, the lower crust and lithospheric mantle is instead eventually replaced by more continental lithosphere from a collided continental fragment. Our suggested model provides a simple basis for unravelling the global geodynamic evolution of the ancient Earth. resent-day orogens of contrasting character can be reduced to which probably began by the Early Ordovician12, and the Early two types on Earth, dominantly accretionary or dominantly Paleozoic accretionary orogens in the easternmost Altaids of Pcollisional, because only the latter are associated with Wilson Asia13.
    [Show full text]
  • Assembly, Configuration, and Break-Up History of Rodinia
    Author's personal copy Available online at www.sciencedirect.com Precambrian Research 160 (2008) 179–210 Assembly, configuration, and break-up history of Rodinia: A synthesis Z.X. Li a,g,∗, S.V. Bogdanova b, A.S. Collins c, A. Davidson d, B. De Waele a, R.E. Ernst e,f, I.C.W. Fitzsimons g, R.A. Fuck h, D.P. Gladkochub i, J. Jacobs j, K.E. Karlstrom k, S. Lu l, L.M. Natapov m, V. Pease n, S.A. Pisarevsky a, K. Thrane o, V. Vernikovsky p a Tectonics Special Research Centre, School of Earth and Geographical Sciences, The University of Western Australia, Crawley, WA 6009, Australia b Department of Geology, Lund University, Solvegatan 12, 223 62 Lund, Sweden c Continental Evolution Research Group, School of Earth and Environmental Sciences, University of Adelaide, Adelaide, SA 5005, Australia d Geological Survey of Canada (retired), 601 Booth Street, Ottawa, Canada K1A 0E8 e Ernst Geosciences, 43 Margrave Avenue, Ottawa, Canada K1T 3Y2 f Department of Earth Sciences, Carleton U., Ottawa, Canada K1S 5B6 g Tectonics Special Research Centre, Department of Applied Geology, Curtin University of Technology, GPO Box U1987, Perth, WA 6845, Australia h Universidade de Bras´ılia, 70910-000 Bras´ılia, Brazil i Institute of the Earth’s Crust SB RAS, Lermontova Street, 128, 664033 Irkutsk, Russia j Department of Earth Science, University of Bergen, Allegaten 41, N-5007 Bergen, Norway k Department of Earth and Planetary Sciences, Northrop Hall University of New Mexico, Albuquerque, NM 87131, USA l Tianjin Institute of Geology and Mineral Resources, CGS, No.
    [Show full text]
  • (Ordovícico) En El Segmento Andino Central Del Orógeno Terra Australis
    XII Congreso Geológico Chileno Santiago, 22-26 Noviembre, 2009 S9_011 La tectónica acrecional oclóyica (Ordovícico) en el segmento andino central del orógeno Terra Australis Astini R.A.1, Martina F.1 1Laboratorio de Análisis de Cuencas, CICTERRA-Universidad Nacional de Córdoba, Av. Velez Sarsfield 1611, 2º piso, of. 7, X5016GCA Córdoba, Argentina. [email protected] En el marco del orógeno acrecional de Terra Australis [1] se reconocen intervalos temporales con acreción de terrenos e interrupción momentánea de la subducción que afectan diferencialmente al margen protoandino y permiten reconocer segmentos con características e historias contrastadas en los Andes. Sobre la base de una revisión conceptual y bibliográfica y de nuevos estudios estratigráficos, geoquímicos e isotópicos en la región del antepaís andino central se propone un mecanismo acrecional alternativo para la etapa de orogénesis ordovícica, que es la de mayor extensión que haya afectado al margen proto-pacífico antes de la orogenia gondwánica, con que finaliza la historia acrecional paleozoica. Dentro de la etapa de orogénesis oclóyica se propone separar la colisión del terreno de Precordillera [2] en el segmento andino central entre 27°30’ y 36°30’ LS aproximadamente (~1000 km de longitud), de la acreción de un bloque alargado (sliver o ribbon terrane) de basamento mesoproterozoico de mucho mayor extensión longitudinal (superior los 2000 km) (Fig. 1) que, de alguna manera, ha sido denominado Occidentalia [3]. Este último incluiría en los Andes Centrales a los terrenos de basamento mesoproterozoico correspondientes a las Sierras Pampeanas Occidentales, ubicados al oeste del cinturón de Famatina y su continuación septentrional en la Puna Catamarqueña (afloramientos de Casadero Grande) y en los terrenos de Arequipa-Antofalla.
    [Show full text]
  • Redalyc.Sr, C and O Isotope Composition of Marbles from The
    Geologica Acta: an international earth science journal ISSN: 1695-6133 [email protected] Universitat de Barcelona España Murra, J.A.; Baldo, E.G.; Galindo, C.; Casquet, C.; Pankhurst, R.J.; Rapela, C.W.; Dahlquist, J. Sr, C and O isotope composition of marbles from the Sierra de Ancasti, Eastern Sierras Pampeanas, Argentina: age and constraints for the Neoproterozoic-Lower Paleozoic evolution of the proto- Gondwana margin Geologica Acta: an international earth science journal, vol. 9, núm. 1, marzo, 2011, pp. 79-92 Universitat de Barcelona Barcelona, España Available in: http://www.redalyc.org/articulo.oa?id=50522124008 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Geologica Acta, Vol.9, Nº 1, March 2011, 79-92 DOI: 10.1344/105.000001645 Available online at www.geologica-acta.com Sr, C and O isotope composition of marbles from the Sierra de Ancasti, Eastern Sierras Pampeanas, Argentina: age and constraints for the Neoproterozoic–Lower Paleozoic evolution of the proto-Gondwana margin 1 1 2 2 3 4 1 J.A. MURRA E.G. BALDO C. GALINDO C. CASQUET R.J. PANKHURST C.W. RAPELA J. DAHLQUIST 1 CICTERRA (Universidad Nacional de Córdoba - Conicet) Av. Vélez Sarsfield 1611, 5016 Córdoba, Argentina. Murra E-mail: [email protected] Baldo E-mail: [email protected] Dahlquist E-mail: [email protected] 2 Departamento. Petrología y Geoquímica Facultad de Ciencias Geológicas, Inst.
    [Show full text]
  • Billion Year Cyclicity Through Earth History: Causes and Consequences
    Geophysical Research Abstracts Vol. 21, EGU2019-12040, 2019 EGU General Assembly 2019 © Author(s) 2019. CC Attribution 4.0 license. Billion year cyclicity through Earth history: causes and consequences William Collins (1), Erin Martin (1), Ross Mitchell (1), Brendan Murphy (2), and Chris Spencer (1) (1) Curtin University, School of Earth & Planetary Sciences, Perth, Australia ([email protected]), (2) St. Francis Xavier University, Department of Earth Sciences, Antigonish, NS, B2G 2W5, Canada A billion year-scale (gigacycle) periodicity in global radiogenic Hf and Sr isotopic trends is investigated by integrating data from tectonics, geodynamics, and palaeomagnetism, in order to build a holistic geodynamic model linking modes of mantle convection to plate tectonic motions over the last 2,500 Myr. The gigacycle reflects an alternating dominance between degree-2 and degree-1 mantle convective flow, manifest as the presence or absence of a hemispheric subduction girdle, respectively. Degree-1 convection involves a single upwelling and opposed downwelling zone, whereas degree-2 has two upwelling zones located antipodally. Present-day convection is degree-2, with the two modern upwelling zones as the Pacific and African superplumes, located on either side of the circum-Pacific subduction girdle. The girdle is geologically recorded by circum-Pacific accretionary orogens, and has existed since ∼550 Myr, indicating that degree-2 convection characterises the Phanerozoic eon. Degree-1 convection resulted in the amalgamation of Columbia ca. 2,000 Myr ago and Gondwana ca. 550 Myr ago accompanied by peaks in crustal reworking (-"Hf), whereas degree-2 convection produced Nuna ca. 1,600 Myr ago and Pangaea 200 Myr ago accompanied by peaks in mantle input (+"Hf).
    [Show full text]
  • A New Record Ofrodinia Break-Up in the Western Sierras Pampeanas of Argentina
    A-type magmatism in the sierras ofMaz and Espinal: A new record ofRodinia break-up in the Western Sierras Pampeanas of Argentina Fernando CoIomboa,,,, Edgardo G.A. BaIdoa, Cesar Casquetb, RobertJ. PankhurstC, Carmen Galindob, CarIos W. RapeIa d, Juan A. DahIquista, C. Mark Fanninge a Departamento de Geologfa - FCEFyN, Universidad NacionaI de Cordoba, Wlez Sarsfield 1611, X5016GCA Cordoba, Argentina b Departamento de Petrologfa y Geoquimica, Universidad Complutense, 28040 Madrid, Spain C British Geological Survey, Keyworth, Nottingham NG12 5GG, England, United Kingdom d Centro de Investigaciones Geologicas, Universidad Nacional de La Plata, 1900 La Plata, Argentina e Research School of Earth Sciences, The Australian National University, Canberra, Australia A BST RAC T Two orthogneisses have been recognized in the sierras of Espinal and Maz (Wes tern Sierras Pampeanas, NWArgentina) that were emplaced within a Grenvillian metasedimentary sequence. Microcline, plagio­ clase and quartz are the main rock-forming minerals, with accessory zircon, apatite-(CaF), magnetite, biotite (Fe/(Fe + Mg) = 0.88-0.91). ferropargasite (Fetotal/(Fetotal + Mg) = 0.88-0.89), titanite (with up to 3 1.61 wt% Y203) and an REE-rich epidote. REE-poor epidote and zoned garnet (Ca and Fe + -rich) are meta­ Keywords: morphic minerals, while muscovite, carbonates and chlorite are secondary phases. Texture is mylonitic. Rodinia Two representative samples are classified as granite (from Sierra de Espinal) and granodiorite/tonalite U-Pb SHRIMP dating Anorogenic magmatism (from Sierra de Maz) on the grounds of immobile trace elements. Some trace element contents are rather Mesoproterozoic high (Zr: 603 and 891 ppm, Y: 44 and 76 ppm, 10,000 x Ga/AI: 2.39-3.89) and indicate an affiliation with Western Sierras Pampeanas A-type granites (more specifically, the A2 group).
    [Show full text]
  • Early Evolution of the Proto-Andean Margin of South America
    Early evolution of the Proto-Andean margin of South America C. W. Rapela Centro de Investigaciones Geológicas, Universidad Nacional de La Plata, Calle 1 No. 644, 1900 La Plata, Argentina R. J. Pankhurst British Antarctic Survey, Cambridge CB30ET, United Kingdom C. Casquet Departamento de Petrología y Geoquímica, Universidad Complutense, 28040 Madrid, Spain E. Baldo J. Saavedra CSIC, Instituto de Agrobiología y Recursos Naturales, 37071 Salamanca, Spain C. Galindo Departamento de Petrología y Geoquímica, Universidad Complutense, 28040 Madrid, Spain ABSTRACT INTRODUCTION From a detailed study of a 500 km transect in the Sierras Pampeanas, central-west Argen- The evolution of the Gondwana margin pro- tina, two pre-Silurian tectono-magmatic episodes are recognized and defined, each culminating posed here is based on new geochemical, isotopic, in micro-continental collisions against the proto-Andean margin of Gondwana. The Pampean petrological, and sedimentological data from a orogeny started in Early Cambrian time with short-lived subduction, indicated by ca. 535 Ma 500 km traverse across the Eastern Sierras Pam- calc-alkaline granitoids. Following Pampean terrane collision, burial to granulite facies condi- peanas and Precordillera (Fig. 1). Pre-Silurian tions (ca. 9 kbar) generated widespread migmatites and ca. 520 Ma highly peraluminous gran- metamorphic and magmatic history is inferred ites in the Eastern Sierras Pampeanas. After brief quiescence, a second major episode, the from (1) dating by conventional U-Pb on abraded Famatinian orogeny, started with subduction ca. 490 Ma, forming a wide continental arc and zircons, U-Pb SHRIMP analyses, and whole-rock ensialic backarc basin. This heralded the approach of Laurentia to Gondwana, during which Rb-Sr and K-Ar, (2) thermo-barometry based on the Precordillera terrane separated from the southern Appalachian region, finally colliding with microprobe mineral analyses, and (3) Nd and Sr Gondwana in Silurian–Devonian time.
    [Show full text]
  • Geology: Ordovician Paleogeography and the Evolution of the Iapetus Ocean
    Ordovician paleogeography and the evolution of the Iapetus ocean Conall Mac Niocaill* Department of Geological Sciences, University of Michigan, 2534 C. C. Little Building, Ben A. van der Pluijm Ann Arbor, Michigan 48109-1063. Rob Van der Voo ABSTRACT thermore, we contend that the combined paleomagnetic and faunal data ar- Paleomagnetic data from northern Appalachian terranes identify gue against a shared Taconic history between North and South America. several arcs within the Iapetus ocean in the Early to Middle Ordovi- cian, including a peri-Laurentian arc at ~10°–20°S, a peri-Avalonian PALEOMAGNETIC DATA FROM IAPETAN TERRANES arc at ~50°–60°S, and an intra-oceanic arc (called the Exploits arc) at Displaced terranes occur along the extent of the Appalachian-Cale- ~30°S. The peri-Avalonian and Exploits arcs are characterized by Are- donian orogen, although reliable Ordovician paleomagnetic data from Ia- nigian to Llanvirnian Celtic fauna that are distinct from similarly aged petan terranes have only been obtained from the Central Mobile belt of the Toquima–Table Head fauna of the Laurentian margin, and peri- northern Appalachians (Table 1). The Central Mobile belt separates the Lau- Laurentian arc. The Precordillera terrane of Argentina is also charac- rentian and Avalonian margins of Iapetus and preserves remnants of the terized by an increasing proportion of Celtic fauna from Arenig to ocean, including arcs, ocean islands, and ophiolite slivers (e.g., Keppie, Llanvirn time, which implies (1) that it was in reproductive communi- 1989). Paleomagnetic results from Arenigian and Llanvirnian volcanic units cation with the peri-Avalonian and Exploits arcs, and (2) that it must of the Moreton’s Harbour Group and the Lawrence Head Formation in cen- have been separate from Laurentia and the peri-Laurentian arc well tral Newfoundland indicate paleolatitudes of 11°S (Table 1), placing them before it collided with Gondwana.
    [Show full text]
  • Locating South China in Rodinia and Gondwana: a Fragment of Greater India Lithosphere?
    Locating South China in Rodinia and Gondwana: A fragment of greater India lithosphere? Peter A. Cawood1, 2, Yuejun Wang3, Yajun Xu4, and Guochun Zhao5 1Department of Earth Sciences, University of St Andrews, North Street, St Andrews KY16 9AL, UK 2Centre for Exploration Targeting, School of Earth and Environment, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia 3State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 4State Key Laboratory of Biogeology and Environmental Geology, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China 5Department of Earth Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China ABSTRACT metamorphosed Neoproterozoic strata and From the formation of Rodinia at the end of the Mesoproterozoic to the commencement unmetamorphosed Sinian cover (Fig. 1; Zhao of Pangea breakup at the end of the Paleozoic, the South China craton fi rst formed and then and Cawood, 2012). The Cathaysia block is com- occupied a position adjacent to Western Australia and northern India. Early Neoproterozoic posed predominantly of Neoproterozoic meta- suprasubduction zone magmatic arc-backarc assemblages in the craton range in age from ca. morphic rocks, with minor Paleoproterozoic and 1000 Ma to 820 Ma and display a sequential northwest decrease in age. These relations sug- Mesoproterozoic lithologies. Archean basement gest formation and closure of arc systems through southeast-directed subduction, resulting is poorly exposed and largely inferred from the in progressive northwestward accretion onto the periphery of an already assembled Rodinia. presence of minor inherited and/or xenocrys- Siliciclastic units within an early Paleozoic succession that transgresses across the craton were tic zircons in younger rocks (Fig.
    [Show full text]
  • A History of Proterozoic Terranes in Southern South America: from Rodinia to Gondwana
    + MODEL GEOSCIENCE FRONTIERS -(-) (2011) 1e9 available at www.sciencedirect.com China University of Geosciences (Beijing) GEOSCIENCE FRONTIERS journal homepage: www.elsevier.com/locate/gsf REVIEW A history of Proterozoic terranes in southern South America: From Rodinia to Gondwana C. Casquet a,*, C.W. Rapela b, R.J. Pankhurst c, E.G. Baldo d, C. Galindo a, C.M. Fanning e, J.A. Dahlquist d, J. Saavedra f a Departamento de Petrologıa y Geoquımica, IGEO (Universidad Complutense, CSIC), 28040 Madrid, Spain b Centro de Investigaciones Geologicas (CONICET-UNLP), 1900 La Plata, Argentina c Visiting Research Associate, British Geological Survey, Keyworth, Nottingham NG12 5GG, United Kingdom d CICTERRA (CONICET-UNC), 5000 Cordoba, Argentina e Research School of Earth Sciences, The Australian National University, Canberra, Australia f Instituto de Agrobiologıa y Recursos Naturales CSIC, 37071 Salamanca, Spain Received 3 August 2011; accepted 8 November 2011 KEYWORDS Abstract The role played by Paleoproterozoic cratons in southern South America from the Mesopro- Paleoproterozoic; terozoic to the Early Cambrian is reconsidered here. This period involved protracted continental amal- Cratons; gamation that led to formation of the supercontinent Rodinia, followed by Neoproterozoic continental Grenvillian; break-up, with the consequent opening of Clymene and Iapetus oceans, and finally continental Neoproterozoic rifting; re-assembly as Gondwana through complex oblique collisions in the Late Neoproterozoic to Early SW Gondwana assembly Cambrian. The evidence for this is based mainly on a combination of precise U-Pb SHRMP dating and radiogenic isotope data for igneous and metamorphic rocks from a large area extending from the Rio de la Plata craton in the east to the Argentine Precordillera in the west and as far north as Arequipa in Peru.
    [Show full text]
  • Early Palaeozoic Continental Growth in the Tasmanides of Northeast Gondwana and Its Implications for Rodinia Assembly and Rifting Chris L
    University of Wollongong Research Online Faculty of Science, Medicine and Health - Papers Faculty of Science, Medicine and Health 2015 Early Palaeozoic continental growth in the Tasmanides of northeast Gondwana and its implications for Rodinia assembly and rifting Chris L. Fergusson University of Wollongong, [email protected] R A. Henderson James Cook University Publication Details Fergusson, C. L. & Henderson, R. A. (2015). Early Palaeozoic continental growth in the Tasmanides of northeast Gondwana and its implications for Rodinia assembly and rifting. Gondwana Research, 28 (3), 933-953. Research Online is the open access institutional repository for the University of Wollongong. For further information contact the UOW Library: [email protected] Early Palaeozoic continental growth in the Tasmanides of northeast Gondwana and its implications for Rodinia assembly and rifting Abstract Gondwana formed in the Neoproterozoic to Cambrian mainly from collision along the East African and Kuunga orogens at about the same time that the Gondwana palaeo-Pacific facing margin became a long-lived active margin and formed the Terra Australis Orogen. This orogen, and in particular the Tasman Orogenic Belt (the Tasmanides) sector of eastern Australia, is distinguished by widespread shortening of quartz turbidite successions and underlying oceanic basement, with less abundant island arc assemblages. Early Palaeozoic accretionary development of the Tasmanides followed Rodinia breakup at 800-750 Ma to form the palaeo-Pacific cO ean. In eastern Australia, a second rifting episode at 600-580 Ma is more widely developed with siliciclastic sedimentation and rift-related igneous activity. In parts of the Delamerian Orogen of South Australia and northwestern New South Wales and in the exposed northern Thomson Orogen of north and central Queensland, the rift-related sedimentary successions have a dominant 1.3 to 1 Ga detrital zircon age signature implying local sources.
    [Show full text]
  • The Making and Unmaking of a Supercontinent: Rodinia Revisited
    Tectonophysics 375 (2003) 261–288 www.elsevier.com/locate/tecto The making and unmaking of a supercontinent: Rodinia revisited Joseph G. Meerta,*, Trond H. Torsvikb a Department of Geological Sciences, University of Florida, 241 Williamson Hall, PO Box 11210 Gainesville, FL 32611, USA b Academy of Sciences (VISTA), c/o Geodynamics Center, Geological Survey of Norway, Leif Eirikssons vei 39, Trondheim 7491, Norway Received 11 April 2002; received in revised form 7 January 2003; accepted 5 June 2003 Abstract During the Neoproterozoic, a supercontinent commonly referred to as Rodinia, supposedly formed at ca. 1100 Ma and broke apart at around 800–700 Ma. However, continental fits (e.g., Laurentia vs. Australia–Antarctica, Greater India vs. Australia– Antarctica, Amazonian craton [AC] vs. Laurentia, etc.) and the timing of break-up as postulated in a number of influential papers in the early–mid-1990s are at odds with palaeomagnetic data. The new data necessitate an entirely different fit of East Gondwana elements and western Gondwana and call into question the validity of SWEAT, AUSWUS models and other variants. At the same time, the geologic record indicates that Neoproterozoic and early Paleozoic rift margins surrounded Laurentia, while similar-aged collisional belts dissected Gondwana. Collectively, these geologic observations indicate the breakup of one supercontinent followed rapidly by the assembly of another smaller supercontinent (Gondwana). At issue, and what we outline in this paper, is the difficulty in determining the exact geometry of the earlier supercontinent. We discuss the various models that have been proposed and highlight key areas of contention. These include the relationships between the various ‘external’ Rodinian cratons to Laurentia (e.g., Baltica, Siberia and Amazonia), the notion of true polar wander (TPW), the lack of reliable paleomagnetic data and the enigmatic interpretations of the geologic data.
    [Show full text]