DOCSLIB.ORG

New Age Constraints for Early Paleogene Strata of Central Patagonia, Argentina: Implications for the Timing of South American Land Mammal Ages

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
New Age Constraints for Early Paleogene Strata of Central Patagonia, Argentina: Implications for the Timing of South American Land Mammal Ages Krause et al. New age constraints for early Paleogene strata of central Patagonia, Argentina: Implications for the timing of South American Land Mammal Ages J. Marcelo Krause1,2,†, William C. Clyde3, Mauricio Ibañez-Mejía4,5, Mark D. Schmitz6, Timothy Barnum3, Eduardo S. Bellosi7, and Peter Wilf8 1CONICET–Museo Paleontológico Egidio Feruglio, Avenida Fontana 140, 9100, Trelew, Argentina 2Departamento de Geología, Universidad Nacional de la Patagonia San Juan Bosco, Ruta Provincial 1 s/n, 9000, Comodoro Rivadavia, Chubut, Argentina 3Department of Earth Sciences, University of New Hampshire, 56 College Road, Durham, New Hampshire 03824, USA 4Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA 5Department of Earth and Environmental Sciences, University of Rochester, Rochester, New York 14627, USA 6Department of Geosciences, Boise State University, 1910 University Drive, Boise, Idaho 83725, USA 7CONICET–Museo Argentino de Ciencias Naturales, Ángel Gallardo 470, 1405 Buenos Aires, Argentina 8Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA ABSTRACT in our new magnetostratigraphic framework, rec ords of regional biotic responses to global we correlate the Peñas Coloradas Formation climatic events (e.g., Raigemborn et al., 2009, The Río Chico Group in the San Jorge to chrons C27n-26r (ca. 62.5 to ca. 61.6 Ma; 2014; Bellosi and González, 2010; Krause et al., Basin of central Patagonia (Argentina) pre- late Danian) and the section from the middle 2010; Dunn et al., 2015; Kohn et al., 2015; serves some of South America’s most signifi- Las Flores to the uppermost Koluel-Kaike to Selkin et al., 2015). cant Paleogene records of biotic and climatic chrons C23n to C19r (ca. 51.4–42.2 Ma; mid Currently, the chronostratigraphy for central change. Three of its constituent formations, Ypresian–late Lutetian). We combine these Patagonia is well constrained for both early the Peñas Coloradas, Las Flores, and Koluel- data with other recently published chrono- Paleo cene (Clyde et al., 2014; Comer et al., Kaike, host vertebrate faunas referred to the stratigraphic results from Paleogene units 2015) and middle-late Paleogene (Ré et al., “Carodnia faunal zone,” the Itaboraian South in Patagonia to better constrain the ages of 2010a, 2010b; Dunn et al., 2013) sequences. American Land Mammal Age (SALMA), noteworthy Paleogene plant and mammal However, the middle Paleocene–middle Eocene and the Riochican SALMA. However, the fossil sites in Patagonia and to develop a re- interval, encompassing the Las Flores and precise absolute ages of these units, and thus vised temporal calibration of the Las Flores, Koluel- Kaike Formations, is still poorly re- their asso ciated faunas and paleoclimate rec- Vacan, and “Sapoan” faunas. solved (see also Woodburne et al., 2014b). Prior ords, are poorly resolved. Herein, we report age constraints on these units came mostly from new paleomagnetic and geochronologic re- INTRODUCTION the underlying and overlying formations. Re- sults from these formations in south-central cent magnetostratigraphic and geochronological Chubut Province, Argentina. U-Pb dating of Paleogene continental sequences from the results from the underlying Salamanca–Peñas four volcanic ashes, using both laser abla tion– San Jorge Basin, central Patagonia, Argentina, Coloradas sequences from the Sarmiento area multicollector–inductively coupled plasma– are globally significant due to their extraor- constrain the age of the Salamanca Formation to mass spectrometry and high-resolution dinary preservation of South American fossil ca. 65.7–63.5 Ma (early-middle Danian; chrons chemical abrasion–isotope dilution–thermal faunas (e.g., Simpson, 1935a, 1935b, 1948; C29n and C28n, where the time scale of Grad- ionization mass spectrometry, indicates ages Cifelli, 1985; Pascual and Ortiz-Jaureguizar, stein et al. [2012] is used throughout this paper) of igneous crystallization of 51.403 ± 0.037 1990; Bonaparte et al., 1993; Bond et al., 1995; and the Peñas Coloradas Formation to ca. 62.5– (0.045) [0.071] Ma for a level within the Flynn and Swisher, 1995; Ortiz-Jaureguizar 61.6 Ma (latest Danian; Chrons C27n-bottom middle Las Flores Formation and 46.714 ± and Cladera, 2006; Gelfo et al., 2009; Madden C26r; Clyde et al., 2014; Comer et al., 2015). 0.012 (0.026) [0.057] Ma, 44.579 ± 0.013 et al., 2010; Woodburne et al., 2014a, 2014b) The base of the Sarmiento Formation, which (0.026) [0.054] Ma, and 42.856 ± 0.017 (0.027) and floras (Berry, 1937; Romero, 1968; Arch- overlies the Koluel-Kaike Formation, is well [0.054] Ma for levels in the lower, middle, and angelsky, 1973, 1976; Petriella and Archangel- constrained at the Gran Barranca locality (Gran upper Koluel-Kaike Formation, respectively. sky, 1975; Archangelsky and Zamaloa, 1986; Barranca Member) to 42.11–41.70 Ma (latest Combining these with previous isotopic ages Zamaloa and Andreis, 1995; Brea et al., 2005, Lutetian, base of chron C19r) based on mag- 2007, 2008, 2011; Iglesias et al., 2007; Zucol netostratigraphic and radioisotopic geochrono- †mkrause@ mef .org .ar et al., 2010). These sequences also provide logic data from the area (Ré et al., 2010a, 2010b; GSA Bulletin; July/August 2017; v. 129; no. 7/8; p. 886–903; doi: 10.1130/B31561.1; 8 figures; 1 table; Data Repository item 2017078; published online 16 March 2017. 886 GeologicalFor permission Society to of copy, America contact [email protected] Bulletin, v. 129, no. 7/8 © 2017 Geological Society of America New age constraints for early Paleogene strata of central Patagonia, Argentina Dunn et al., 2013, and references cited therein). 1949; Legarreta and Uliana, 1994; Krause et al., Crocodilian coprolites were also described from Two radioisotopic dates were also recently re- 2010; Raigemborn et al., 2010; Comer et al., the Las Flores Formation in the coastal area ported from the Las Flores Formation, which 2015). Our study site, Las Flores, is located on of Pico Salamanca, 4–5 km to the east of Bajo underlies the Koluel-Kaike Formation. One is a the eastern margin of the San Bernardo fold belt Palangana (Krause and Piña, 2012). 40Ar/39Ar date of 49.512 ± 0.019 Ma on alkaline in the San Jorge Basin, southern Argentina (Fig. The Koluel-Kaike Formation, in the feldspars from a tuff in the lower portion of the 1A–1C), at the eastern extreme of the fossilifer- past known as the Argiles Fissilaires facies formation, 20 m above the beds bearing the Las ous Gran Barranca escarpment (Fig. 1C). An ad- (Ameghino, 1906; McCartney, 1934) or “Tobas Flores fauna (Woodburne et al., 2014b). The ditional locality, Cerro Blanco (Fig. 1C), 26 km de Koluel-Kaike” (Feruglio, 1949), is mainly other is a maximum age of sedimentation inter- SW of Las Flores, also was included in order composed of pyroclastic sediments in the form preted from laser ablation–inductively coupled to sample a volcanic tuff from the middle Las of fine tuffs and bentonites (Krause et al., 2010; plasma–mass spectrometry (LA-ICP-MS) U-Pb Flores Formation for isotopic dating. Raigemborn et al., 2010). Conspicuous lenticu- analyses of detrital zircons, which constrained Under the Las Flores Formation sits the Peñas lar bodies with manganese nodules are pres- the bed bearing the Las Flores fauna to be no Coloradas Formation, a fluvial unit up to 42 m ent at the base, recording shallow pond facies older than ca. 47 ± 1 Ma (Kohn et al., 2015). in thickness (e.g., at Estancia la Rosa; Raigem- (Krause et al., 2010). Strongly developed red- These conflicting ages confound chronostrati- born et al., 2010) but typically less than 30 m dish paleosols with a moderate to high degree of graphic interpretation of the Las Flores Forma- thick (Krause, 2010). The rocks composing silicification are frequent throughout the section tion in this area. the Peñas Coloradas Formation are mainly (Krause et al., 2010). At Las Flores, the Koluel- In this study, we constrain the ages of the medium- dark reddish, cross-bedded sandstones, Kaike Formation exhibits gradational contacts Peñas Coloradas, Las Flores, and Koluel-Kaike related to sinuous channel filling, and subordi- with both the underlying Las Flores Formation Formations using new radioisotopic and paleo- nate mudstones and tuffs deposited in floodplain and the overlying Sarmiento Formation (Bellosi magnetic data in the Las Flores area, which lies settings (e.g., Raigemborn et al., 2009, 2010; and Madden, 2005; Krause et al., 2010, their at the eastern extreme of the Gran Barranca in Comer et al., 2015). According to Bond et al. figs. 3A and 3B). south-central Chubut Province, Patagonia, (1995) and Woodburne et al. (2014a, 2014b), Fossils are scarce in the Koluel-Kaike For- Argen tina (Figs. 1A–C; Table 1). Our goals are to among others, the Peñas Coloradas Formation mation, but silicified wood (Brea et al., 2009) develop a well-defined stratigraphic framework contains vertebrate remains from the “Carodnia and cicada trace fossils (Krause et al., 2008) for the San Jorge Basin, so as to better constrain faunal zone,” originally described by Simpson have been recorded. Mammalian remains have the ages of some of the most significant records (1935a, 1935b) from Bajo Palangana and Cerro never been found in the Koluel-Kaike Forma- of Paleogene biotas in South America, and to Redondo (Fig. 1B); however, this fauna is prob- tion itself (e.g., Simpson, 1933a). However, establish a chronostratigraphic framework for ably contained within the Las Flores Formation siliciclastic rocks exposed along the Atlantic improved interpretation of the important early (see Discussion). Fossil wood has also been de- coast, correlated with the Koluel-Kaike Forma- Paleogene global climatic events recorded in scribed from the Peñas Coloradas Formation in tion by Legarreta and Uliana (1994), contain South America. Improved chronostratigraphic the area around the town of Sarmiento and at mammal fossils from the Ernestokokenia faunal data allow more precise correlation to other Punta Peligro along the coast (Brea et al., 2004; zone (= Riochican SALMA; Bond et al., 1995).
Load more

Recommended publications
  • Pineda-Salgado, 2020 CD
    Universidad Nacional de La Plata Facultad de Ciencias Naturales y Museo Análisis de concentraciones fósiles en la Formación Monte León (Mioceno inferior), en la costa de la provincia de Santa Cruz Gabriela Pineda Salgado Tesis doctoral Directores: Miguel Griffin, Ana Parras 2020 A mi mamá, mi abuela y mi abuelichi A Señor Pantufla y Spock-Uhura, los félidos con más estilo Agradecimientos Al Posgrado de la Facultad de Ciencias Naturales y Museo de la Universidad Nacional de La Plata. A los doctores Miguel Griffin y Ana Parras por dirigirme, por todas las facilidades brindadas para la realización de este trabajo, así como por su ayuda en las labores de campo y por los apoyos obtenidos para exponer parte de los resultados del mismo en reuniones nacionales e internacionales. Al jurado conformado por los doctores Claudia del Río, Miguel Manceñido y Sven Nielsen. A la Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT) por la beca doctoral otorgada a través del Fondo para la Investigación Científica y Tecnológica (FONCyT), en el marco del Proyecto de Investigación Científica y Tecnológica PICT 2012-1726. Al Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) por la beca interna de finalización de doctorado otorgada durante el periodo 2017-2019. Al Instituto de Ciencias de la Tierra y Ambientales de La Pampa (INCITAP, CONICET- UNLPam) y a la Facultad de Ciencias Exactas y Naturales de la UNLPam por ceder el espacio institucional para el desarrollo de esta tesis. A la Administración de Parques Nacionales por autorizar la recolección de muestras en los límites del Parque Nacional Monte León.
    [Show full text]
  • Chronostratigraphy of the Mammal-Bearing Paleocene of South America 51
    Thierry SEMPERE biblioteca Y. Joirriiol ofSoiiih Ainorirari Euirli Sciriin~r.Hit. 111. No. 1, pp. 49-70, 1997 Pergamon Q 1‘197 PublisIlcd hy Elscvicr Scicncc Ltd All rights rescrvcd. Printed in Grcnt nrilsin PII: S0895-9811(97)00005-9 0895-9X 11/97 t I7.ol) t o.(x) -. ‘Inshute qfI Human Origins, 1288 9th Street, Berkeley, California 94710, USA ’Orstom, 13 rue Geoffroy l’Angevin, 75004 Paris, France 3Department of Geosciences, The University of Arizona, Tucson, Arizona 85721, USA Absfract - Land mammal faunas of Paleocene age in the southern Andean basin of Bolivia and NW Argentina are calibrated by regional sequence stratigraphy and rnagnetostratigraphy. The local fauna from Tiupampa in Bolivia is -59.0 Ma, and is thus early Late Paleocene in age. Taxa from the lower part of the Lumbrera Formation in NW Argentina (long regarded as Early Eocene) are between -58.0-55.5 Ma, and thus Late Paleocene in age. A reassessment of the ages of local faunas from lhe Rfo Chico Formation in the San Jorge basin, Patagonia, southern Argentina, shows that lhe local fauna from the Banco Negro Infeiior is -60.0 Ma, mak- ing this the most ancient Cenozoic mammal fauna in South,America. Critical reevaluation the ltaboraí fauna and associated or All geology in SE Brazil favors lhe interpretation that it accumulated during a sea-level lowsland between -$8.2-56.5 Ma. known South American Paleocene land inammal faunas are thus between 60.0 and 55.5 Ma (i.e. Late Paleocene) and are here assigned to the Riochican Land Maminal Age, with four subages (from oldest to youngest: Peligrian, Tiupampian, Ilaboraian, Riochican S.S.).
    [Show full text]
  • Southward-Directed Subduction of the Farallon–Aluk Spreading Ridge and Its Impact on Subduction Mechanics and Andean Arc Magmatism: Insights From
    feart-08-00121 May 7, 2020 Time: 11:30 # 1 ORIGINAL RESEARCH published: 08 May 2020 doi: 10.3389/feart.2020.00121 Southward-Directed Subduction of the Farallon–Aluk Spreading Ridge and Its Impact on Subduction Mechanics and Andean Arc Magmatism: Insights From Edited by: Marina Manea, Geochemical and Seismic National Autonomous University of Mexico, Mexico Tomographic Data Reviewed by: 1,2 1,2 1,2 1,2 Luca Ferrari, Sofía B. Iannelli *, Lucía Fernández Paz , Vanesa D. Litvak , Guido Gianni , Geosciences Center, National Lucas M. Fennell1,2, Javiera González3, Friedrich Lucassen4, Simone Kasemann4, Autonomous University of Mexico, Verónica Oliveros3 and Andrés Folguera1,2 Mexico 1 2 Jiashun Hu, Departamento de Ciencias Geológicas, Universidad de Buenos Aires, Buenos Aires, Argentina, Instituto de Estudios 3 California Institute of Technology, Andinos ‘Don Pablo Groeber’, CONICET- Universidad de Buenos Aires, Buenos Aires, Argentina, Departamento 4 United States de Ciencias de la Tierra, Universidad de Concepción, Concepción, Chile, MARUM - Center for Marine Environmental Sciences and Faculty of Geosciences, University of Bremen, Bremen, Germany *Correspondence: Sofía B. Iannelli sofi[email protected] Since the initial proposal of the past existence of a southward-directed mid-ocean ridge–subduction interaction in the Andes during Late Cretaceous–Paleogene times, Specialty section: This article was submitted to several studies have been devoted to uncover the tectonomagmatic evidence of this Structural Geology and Tectonics, process. The collision of a spreading ridge against a subduction margin provokes a section of the journal important tectonomagmatic changes, including, between them, variations in arc-related Frontiers in Earth Science magmatic activity and in the plate-margin stress regime.
    [Show full text]
  • And Ordovician (Sardic) Felsic Magmatic Events in South-Western Europe: Underplating of Hot Mafic Magmas Linked to the Opening of the Rheic Ocean
    Solid Earth, 11, 2377–2409, 2020 https://doi.org/10.5194/se-11-2377-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Comparative geochemical study on Furongian–earliest Ordovician (Toledanian) and Ordovician (Sardic) felsic magmatic events in south-western Europe: underplating of hot mafic magmas linked to the opening of the Rheic Ocean J. Javier Álvaro1, Teresa Sánchez-García2, Claudia Puddu3, Josep Maria Casas4, Alejandro Díez-Montes5, Montserrat Liesa6, and Giacomo Oggiano7 1Instituto de Geociencias (CSIC-UCM), Dr. Severo Ochoa 7, 28040 Madrid, Spain 2Instituto Geológico y Minero de España, Ríos Rosas 23, 28003 Madrid, Spain 3Dpt. Ciencias de la Tierra, Universidad de Zaragoza, 50009 Zaragoza, Spain 4Dpt. de Dinàmica de la Terra i de l’Oceà, Universitat de Barcelona, Martí Franquès s/n, 08028 Barcelona, Spain 5Instituto Geológico y Minero de España, Plaza de la Constitución 1, 37001 Salamanca, Spain 6Dpt. de Mineralogia, Petrologia i Geologia aplicada, Universitat de Barcelona, Martí Franquès s/n, 08028 Barcelona, Spain 7Dipartimento di Scienze della Natura e del Territorio, 07100 Sassari, Italy Correspondence: J. Javier Álvaro ([email protected]) Received: 1 April 2020 – Discussion started: 20 April 2020 Revised: 14 October 2020 – Accepted: 19 October 2020 – Published: 11 December 2020 Abstract. A geochemical comparison of early Palaeo- neither metamorphism nor penetrative deformation; on the zoic felsic magmatic episodes throughout the south- contrary, their unconformities are associated with foliation- western European margin of Gondwana is made and in- free open folds subsequently affected by the Variscan defor- cludes (i) Furongian–Early Ordovician (Toledanian) activ- mation.
    [Show full text]
  • Masterarbeit
    MASTERARBEIT Titel der Masterarbeit Late Cretaceous Volcaniclastic Rocks in the Pontides (NW Turkey) verfasst von Katharina Böhm BSc angestrebter akademischer Grad Master of Science (M.Sc.) Wien, 2015 Studienkennzahl lt. Studienblatt: A 066 815 Studienrichtung lt. Studienblatt: Erdwissenschaften Betreuerin / Betreuer: Ao. Univ.-Prof. Dr. Michael Wagreich Declaration ”I hereby declare that this master’s thesis was authored by myself independently, without use of other sources than indicated. I have explicitly cited all material which has been quoted either literally or by content from the used sources. Further this work was neither submitted in Austria nor abroad for any degree or examination.” Contents Declaration2 1. Introduction8 1.1. Project.................................. 9 1.1.1. Goals............................... 9 1.2. Geographical setting.......................... 10 1.3. Geological setting............................ 12 1.3.1. The Pontides........................... 14 1.3.2. The Pontides in the Cretaceous................ 18 1.3.3. Correlation with relative ages.................. 24 2. Nomenclature 28 3. Methods 29 3.1. ICP-ES and ICP-MS........................... 29 3.2. PXRD.................................. 29 3.3. Heavy mineral extraction........................ 30 4. Results 31 4.1. Mineralogy................................ 31 4.1.1. Powder X-Ray diffraction.................... 31 4.1.2. Thin sections.......................... 33 4.1.3. Mineral Extraction: Dating of minerals............. 34 4.2. Geochemistry.............................. 36 5. Interpretation of the geochemical results 37 5.1. Mobility of elements........................... 37 5.2. Alteration of minerals.......................... 39 5.3. Determining the rock type........................ 41 3 5.4. Discriminating volcanic series..................... 48 5.5. Revealing the tectonic setting...................... 52 5.6. Plotting geochemical element patterns................. 60 5.7. Summary of the geochemical classification.............. 62 6.
    [Show full text]
  • A Dated Phylogeny of Marsupials Using a Molecular Supermatrix and Multiple Fossil Constraints
    Journal of Mammalogy, 89(1):175–189, 2008 A DATED PHYLOGENY OF MARSUPIALS USING A MOLECULAR SUPERMATRIX AND MULTIPLE FOSSIL CONSTRAINTS ROBIN M. D. BECK* School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia Downloaded from https://academic.oup.com/jmammal/article/89/1/175/1020874 by guest on 25 September 2021 Phylogenetic relationships within marsupials were investigated based on a 20.1-kilobase molecular supermatrix comprising 7 nuclear and 15 mitochondrial genes analyzed using both maximum likelihood and Bayesian approaches and 3 different partitioning strategies. The study revealed that base composition bias in the 3rd codon positions of mitochondrial genes misled even the partitioned maximum-likelihood analyses, whereas Bayesian analyses were less affected. After correcting for base composition bias, monophyly of the currently recognized marsupial orders, of Australidelphia, and of a clade comprising Dasyuromorphia, Notoryctes,and Peramelemorphia, were supported strongly by both Bayesian posterior probabilities and maximum-likelihood bootstrap values. Monophyly of the Australasian marsupials, of Notoryctes þ Dasyuromorphia, and of Caenolestes þ Australidelphia were less well supported. Within Diprotodontia, Burramyidae þ Phalangeridae received relatively strong support. Divergence dates calculated using a Bayesian relaxed molecular clock and multiple age constraints suggested at least 3 independent dispersals of marsupials from North to South America during the Late Cretaceous or early Paleocene. Within the Australasian clade, the macropodine radiation, the divergence of phascogaline and dasyurine dasyurids, and the divergence of perameline and peroryctine peramelemorphians all coincided with periods of significant environmental change during the Miocene. An analysis of ‘‘unrepresented basal branch lengths’’ suggests that the fossil record is particularly poor for didelphids and most groups within the Australasian radiation.
    [Show full text]
  • Fossil History of Curculionoidea (Coleoptera) from the Paleogene
    geosciences Review Fossil History of Curculionoidea (Coleoptera) from the Paleogene Andrei A. Legalov 1,2 1 Institute of Systematics and Ecology of Animals, Siberian Branch, Russian Academy of Sciences, Ulitsa Frunze, 11, 630091 Novosibirsk, Novosibirsk Oblast, Russia; [email protected]; Tel.: +7-9139471413 2 Biological Institute, Tomsk State University, Lenin Ave, 36, 634050 Tomsk, Tomsk Oblast, Russia Received: 23 June 2020; Accepted: 4 September 2020; Published: 6 September 2020 Abstract: Currently, some 564 species of Curculionoidea from nine families (Nemonychidae—4, Anthribidae—33, Ithyceridae—3, Belidae—9, Rhynchitidae—41, Attelabidae—3, Brentidae—47, Curculionidae—384, Platypodidae—2, Scolytidae—37) are known from the Paleogene. Twenty-seven species are found in the Paleocene, 442 in the Eocene and 94 in the Oligocene. The greatest diversity of Curculionoidea is described from the Eocene of Europe and North America. The richest faunas are known from Eocene localities, Florissant (177 species), Baltic amber (124 species) and Green River formation (75 species). The family Curculionidae dominates in all Paleogene localities. Weevil species associated with herbaceous vegetation are present in most localities since the middle Paleocene. A list of Curculionoidea species and their distribution by location is presented. Keywords: Coleoptera; Curculionoidea; fossil weevil; faunal structure; Paleocene; Eocene; Oligocene 1. Introduction Research into the biodiversity of the past is very important for understanding the development of life on our planet. Insects are one of the Main components of both extinct and recent ecosystems. Coleoptera occupied a special place in the terrestrial animal biotas of the Mesozoic and Cenozoics, as they are characterized by not only great diversity but also by their ecological specialization.
    [Show full text]
  • IV. Northern South America EIA/ARI World Shale Gas and Shale Oil Resource Assessment
    IV. Northern South America EIA/ARI World Shale Gas and Shale Oil Resource Assessment IV. NORTHERN SOUTH AMERICA SUMMARY Northern South America has prospective shale gas and shale oil potential within marine- deposited Cretaceous shale formations in three main basins: the Middle Magdalena Valley and Llanos basins of Colombia, and the Maracaibo/Catatumbo basins of Venezuela and Colombia, Figure IV-1. The organic-rich Cretaceous shales (La Luna, Capacho, and Gacheta) sourced much of the conventional gas and oil produced in Colombia and western Venezuela, and are similar in age to the Eagle Ford and Niobrara shale plays in the USA. Ecopetrol, ConocoPhillips, ExxonMobil, Shell, and others have initiated shale exploration in Colombia. Colombia’s petroleum fiscal regime is considered attractive to foreign investment. Figure IV-1: Prospective Shale Basins of Northern South America Source: ARI 2013 May 17, 2013 IV-1 IV. Northern South America EIA/ARI World Shale Gas and Shale Oil Resource Assessment For the current EIA/ARI assessment, the Maracaibo-Catatumbo Basin was re-evaluated while new shale resource assessments were undertaken on the Middle Magdalena Valley and Llanos basins. Technically recoverable resources (TRR) of shale gas and shale oil in northern South America are estimated at approximately 222 Tcf and 20.2 billion bbl, Tables IV-1 and IV- 2. Colombia accounts for 6.8 billion barrels and 55 Tcf of risked TRR, while western Venezuela has 13.4 billion barrels and 167 Tcf. Eastern Venezuela may have additional potential but was not assessed due to lack of data. Colombia’s first publicly disclosed shale well logged 230 ft of over-pressured La Luna shale with average 14% porosity.
    [Show full text]
  • Baez NHM 1997.Pdf (3.622Mb)
    HERP QL 668 B33 l':iif;,O0i.U'.Z06l("'^ ocxentxpc Papers Natural History Museum The University of Kansas 29 October 1997 Number 4:1^1 Redescription of the Paleogene Shelania pascuali from Patagonia and Its Bearing on the Relationships of Fossil and Recent Pipoid Frogs >. By o O Ana Maria BAez^ and Linda Trueb- o ^Departamento de Geologia, FacuUad de Ciencias Exactas, Universidad de 0) w >. > t- Buenos Aires, Pabellon II, Ciudad Universitaria, 1428 Buenos Aires, Argentina CO !-> >^ ^ £ -^ '^Division of Herpetology, Natural Histoiy Museum, and Department of P Kansas 66045-2454, J3 o, Systematics and Ecology, The University of Kansas, Lawrence, USA a o t3 o CO ^ t. CONTENTS ° CO I ABSTRACT 2 « RESUMEN 2 5S INTRODUCTION 2 Previous Paleontological Work 4 Acknowledgments 4 MATERIALS AND METHODS 5 General Methodology 5 Cladistic Methodology 5 Specimens Examined 6 STRATIGRAPHIC PROVENANCE AND AGE OF MATERIAL 6 REDESCRIPTION OF SHELANIA 8 ANALYSIS OF CHARACTERS 16 RESULTS 31 DISCUSSION 35 Taxonomic Considerations 35 Characters 36 LITERATURE CITED 37 APPENDIX 40 © Natural History Museum, The University of Kansas ISSN No. 1094-0782 — 2 Scientific Papers, Natural History Museum, The University of Kansas 1960, is redescribed on the basis of a series of 30 recently I ABSTIMCT Shdania pascuali Casamiquela, .'-\ ' . discovered specimens, which range in estimated snout-vent length from 30-100 mm, from the Paleo- y ' gene of Patagonia. This large pipoid anuran is distinguished by possessing a long, narrow braincase; an hourglass-shaped frontoparietal; a robust antorbital process on the edentate maxilla; long, straight {/) '/^ I ilia that describe a V-shape in dorsal profile; and a trunk that is long relative to the lengths of the head and limbs.
    [Show full text]
  • The Cretaceous Igneous Rocks in Southeastern Guangxi and Their Implication for Tectonic Environment in Southwestern South China Block
    Open Geosciences 2020; 12: 518–531 Research Article Yang Liu, Nianqiao Fang*, Menglin Qiang, Lei Jia, and Chaojie Song The Cretaceous igneous rocks in southeastern Guangxi and their implication for tectonic environment in southwestern South China Block https://doi.org/10.1515/geo-2020-0160 Keywords: high-magnesian andesites 1, I-type granite 2, received January 9, 2020; accepted May 13, 2020 clastoporphyritic lava 3, Neo-Tethyan Subduction 4, Abstract: Southeastern Guangxi is located in the south- Southwestern South China Block 5 western South China Block and to the northwest of the South China Sea (SCS), with abundant records of the Cretaceous magmatism. A detailed study of igneous rocks will contribute to a better understanding of the late 1 Introduction Mesozoic tectonic environment. Zircon U–Pb dating yields ages of 93.37 ± 0.43 Ma for Yulin andesites and 107.6 ± South China Block lies between the Tethyan tectonic belt fi [ ] 1.2 Ma for Luchuan granites. Yulin andesites are hornblende and Paci c tectonic belt 1 .Itisacrucialperiodfor andesites, of which w(MgO) is between 7.72% and 8.42%, magmatic rocks and mineralization in southwestern South and Mg# is between 66.7 and 68.0, belonging to high China Block in Cretaceous, especially in the range of – [ ] magnesian andesites (HMAs) from peridotite sources. 100 90 Ma 2 . These magmatic rocks are a key to study Luchuan granites are medium- to fine-grained monzogra- the tectonic evolution in this region. More research has - nites. Monzogranites and clastoporphyritic lava are high-K been done by predecessors, including Kunlunguan bath calc-alkaline series and metaluminum to weakly peralumi- olith, Dali rock mass and Dachang dike group with nous series, which belong to the I-type granites.
    [Show full text]
  • Mammalia, Notoungulata), from the Eocene of Patagonia, Argentina
    Palaeontologia Electronica palaeo-electronica.org An exceptionally well-preserved skeleton of Thomashuxleya externa (Mammalia, Notoungulata), from the Eocene of Patagonia, Argentina Juan D. Carrillo and Robert J. Asher ABSTRACT We describe one of the oldest notoungulate skeletons with associated cranioden- tal and postcranial elements: Thomashuxleya externa (Isotemnidae) from Cañadón Vaca in Patagonia, Argentina (Vacan subage of the Casamayoran SALMA, middle Eocene). We provide body mass estimates given by different elements of the skeleton, describe the bone histology, and study its phylogenetic position. We note differences in the scapulae, humerii, ulnae, and radii of the new specimen in comparison with other specimens previously referred to this taxon. We estimate a body mass of 84 ± 24.2 kg, showing that notoungulates had acquired a large body mass by the middle Eocene. Bone histology shows that the new specimen was skeletally mature. The new material supports the placement of Thomashuxleya as an early, divergent member of Toxodon- tia. Among placentals, our phylogenetic analysis of a combined DNA, collagen, and morphology matrix favor only a limited number of possible phylogenetic relationships, but cannot yet arbitrate between potential affinities with Afrotheria or Laurasiatheria. With no constraint, maximum parsimony supports Thomashuxleya and Carodnia with Afrotheria. With Notoungulata and Litopterna constrained as monophyletic (including Macrauchenia and Toxodon known for collagens), these clades are reconstructed on the stem
    [Show full text]
  • Changes of the Palynobiotas in the Mesozoic and Cenozoic of Patagonia: a Review
    Biological Journal of the Linnean Society, 2011, 103, 380–396. With 6 figures Changes of the palynobiotas in the Mesozoic and Cenozoic of Patagonia: a review MIRTA E. QUATTROCCHIO1,2*, WOLFGANG VOLKHEIMER3, ANA MARÍA BORRROMEI1 and MARCELO A. MARTÍNEZ1,2 1INGEOSUR, CONICET, San Juan 670, (8000), Bahía Blanca, Argentina 2Departamento de Geología, Universidad Nacional del Sur, San Juan 670, (8000) Bahía Blanca, Argentina 3IANIGLA, CCT-CONICET, CC330 (5500) Mendoza, Argentina Received 22 February 2011; accepted for publication 22 February 2011bij_1652 380..396 This study describes the compositional changes of Mesozoic–Cenozoic palynologic assemblages in Patagonia, the succession of phytogeographic scenarios and some evolutionary key events. The Triassic ‘Ipswich Microflora’, characterized by bisaccate pollen and high frequencies of trilete spores, represents the warm–temperate province of south-western Gondwana (Dicroidium Flora), followed in time, in Patagonia, near the Triassic/Jurassic bound- ary, by the ‘Classopollis Microflora’, indicating warm and (seasonal) arid conditions. Araucariaceans and podocar- paceans grew on Jurassic uplands. The exclusively Early Cretaceous taxa Cyclusphaera and Balmeiopsis (Coniferae) appeared in the Valanginian. The oldest angiospermous pollen types of Argentina appear in the Barremian–Aptian of southern Patagonia. During the Maastrichtian, the Nothofagaceae and Myrtaceae are incoming. In the Palaeocene, a vegetation dominated by tropical elements would have developed in Patagonia. Increasing Nothofagidites frequency in northern Patagonia during the Middle to Late Eocene indicates climatic change from warm to temperate. Of three Early to Middle Miocene phytogeographic provinces (Neotropical– Transitional and Austral), the Transitional one was replaced during the Late Miocene–Pliocene by the xerophytic Proto Espinal/Steppe with a shrubby–herbaceous vegetation.
    [Show full text]