DOCSLIB.ORG

Taxonomy, Biostratigraphy, and Palaeobiogeography

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Taxonomy, Biostratigraphy, and Palaeobiogeography Lower Tithonian microconchiate simoceratins from eastern Mexico: Taxonomy, biostratigraphy, and palaeobiogeography ANA B. VILLASEÑOR, FEDERICO OLÓRIZ, and CELESTINA GONZÁLEZ−ARREOLA Villaseñor, A.B., Olóriz, F., and González−Arreola, C. 2011. Lower Tithonian microconchiate simoceratins from eastern Mexico: Taxonomy, biostratigraphy, and palaeobiogeography. Acta Palaeontologica Polonica 56 (1): 133–158. The precise record of simoceratins sampled bed−by−bed is first reported from Mexico (Mazatepec area in Puebla, cen− tral−eastern Mexico), as well as the existence of lappeted peristomes in these ammonites. Both Pseudovolanoceras aesinense and the subspecies Pseudovolanoceras aesinense chignahuapense are shown to occur among Mexican simoceratins. The European species and the Mexican subspecies share the same stratigraphic range in the studied sec− tions, yet they differ in ephebic sculpture. Ecological adaptation to neritic seas corresponding to eastern Mexico areas is interpreted, forcing phenotypic deviation with geographic significance, i.e., subspeciation. The new subspecies would in− dicate stratigraphic horizons within the Semiformiceras semiforme/Haploceras verruciferum Chronozone in the Mediter− ranean Tethys. A revision of contemporaneous simoceratins in the Americas is founded on a comparative analysis with respect to the European species P. aesinense. Key words: Ammonitina, Pseudovolanoceras, Tithonian, Upper Jurassic, Mexico. Ana Bertha Villaseñor [[email protected]] and Celestina González−Arreola [[email protected]], Departamento de Paleontología, Instituto de Geología, UNAM. C. P. 04510, México, DF Mexico; Federico Olóriz [[email protected]], Departamento de Estratigrafía y Paleontología, Facultad de Ciencias, Universidad de Granada, Campus Universitario de Fuente Nueva, 18002, Granada, Spain. Received 22 March 2010, accepted 26 July 2010, available online 16 August 2010. Introduction Servizio Geologico d’Italia, Roma, Italy; GPIBO, Goldfuss− Museum und Paläontologisches Institut der Universität Bonn, Upper Jurassic deposits from East−Central Mexico have long Germany; IGM, National Paleontological Collection (Museo been investigated due to their importance for oil exploration. Maria Carmen Perrilliat Montoya), Institute of Geology, Mex− Cantú−Chapa (1967) gave valuable preliminary information ico City, Mexico; NS3Col, Museo di Paleontologia dell’Uni− about Middle Tithonian to Berriasian ammonites gathered versità di Roma, Italy; Rin, Collection housed in the Comune from outcrops in the Mazatepec area, Puebla, Mexico. Cantú− di Piobicco, Pesaro, Italy; SMNS, Staatlisches Museum für Chapa (1989) proposed a type−section for the Tithonian– Naturkunde, Stuttgart, Germany; UNAM, Universidad Nacio− Berriasian boundary in the Mazatepec area, and Adatte et al. nal Autónoma de México, Mexico; USNM, United States (1992) provided a precise biostratigraphy for calpionellids, in− Natural Museum, New York, USA. dicating the Jurassic–Cretaceous boundary in the area. On the Other abbreviations.—Ac, A; Cantú−Chapa collection; C, basis of calpionellid and ammonite biostratigraphy, Stinnes− number of constrictions; CT, Colle Tordina (Monti della beck et al. (1993) questioned the previous proposal for the Rossa, Appennino Marchigiano), Italy; Dm, measured shell Jurassic/Cretaceous boundary type−section made by Cantú− diameter; M, macroconchs; m, microconchs; FAD, first oc− Chapa (1989). A further approach to sedimentology and dia− currence datum; MTQ, Mazatepec Quesos section in the genesis in Kimmeridgian deposits of the “San Andrés” For− Apulco River area in Fig. 2; PS, periumbilical sculpture; mation at Jonotla (Puebla) and Tlacolula (Veracruz), a region PS/2, number of periumbilical sculptural elements, ribs, bul− which includes the Mazatepec area, was made by Hernández lae or tubercles, per half−a−whorl; U, umbilical size; U/D, De La Fuente (1996). size ratio between the umbilicus and shell diameter; Wh, Institutional abbreviation.—BSPG, Bayerische Staatssamm− whorl height; Wh/D, size ratio between whorl height and lung für Paläontologie und Geologie, Munich, Germany; shell diameter; specimen number a, b, letters refer to mould CCS, Material housed in the Museo di Paleontologia del and cast of the same specimen. Acta Palaeontol. Pol. 56 (1): 133–158, 2011 doi:10.4202/app.2010.0030 134 ACTA PALAEONTOLOGICA POLONICA 56 (1), 2011 20o 01' 32'' Mazatepec town MEXICO * Mazatepec area Apulco sections Hydroelectric MT-2 Puebla station MTQ Apulco river 1km 20o 00' 00'' 97o 25' 21" 97o 24' 39" Fig. 1. Location of the studied sections. A. Regional location for Puebla state. B. Inlet for the precise location of the sections investigated on the banks of the Apulco River in the Mazatepec area. (Figs. 1, 2) and shows a 22 m thick succession made of Geological setting brownish, more or less calcareous siltstones and silty lime− stones (Tamán Formation) containing decimetre to metre The geological locality Apulco River section MT−2 lies within size concretions in the lower and middle part of the section. the Apulco Valley, Sierra Norte de Puebla, near the village of Mazatepec, Puebla (Figs. 1, 2). This mountainous region be− longs to the geologic subprovince of Eastern Sierra Madre Historical background (López Ramos 1979a: 291, figs. 6−1, 6−8) and the Mexican Fold−and−Thrust Belt (Suter 1990; a geologic province ac− An overview of Upper Jurassic rocks and palaeoenvironments cording to Ortega−Gutiérrez et al. 1992) where NNW–SSE in the Apulco Valley, located in Sierra Norte de Puebla be− trending folds are interrupted southward by rocks of the Trans− tween Jonotla (Puebla) and Tlacolula (Veracruz), was given mexican Volcanic Axis or Belt. by Hernández De La Fuente (1996). In studying fossiliferous Upper Jurassic outcrops above the Apulco River banks are sections of the area, this author included some outcrops men− difficult to access due to dense forest coverage in the area near tioned by Cantú−Chapa (1971: fig. 1). In his geological local− Mazatepec. The Upper Jurassic section shows a lower, coarse ity Apulco River, Hernández De La Fuente (1996) collected bedded part containing mid−shelf to lower−ramp carbonates Idoceras sp., Mazapilites sp., and Uhligites sp. (without illus− (San Andres Formation; Hernández De La Fuente 1996). tration), and mentioned the common occurrence of ammonites Overlying it are thinner bedded, brownish to grey−black silt− within the Tamán Formation. stones with silty interbeds and occasional calcareous horizons Over the past ten years, two of us (ABV and FO) have showing common, mainly parallel, fine cross lamination (up− studied outcrops around the Apulco River as part of a research per Lower Kimmeridgian and Tithonian Tamán Formation; programme focusing on sections of the San Andrés, Tamán, see Cantú−Chapa 1971 for regional biostratigraphy and corre− and Pimienta Formations, to provide a precise biostratigraphy lation). Regional deepening is 108° to 308° NE, and common based on bed−by−bed sampling (e.g., Villaseñor et al. 2000a, faulting impedes precise lateral observation and correla− 2003; Villaseñor and Olóriz 2001, 2009; López−Caballero tion among outcrops. Evidence of synsedimentary sliding 2006; López−Caballero et al. 2007). (slumps) and horizons containing more calcareous concre− This paper presents the palaeontological analysis carried tions are common in the Lower Tithonian succession. Cover− out on the first specimens of simoceratins collected bed−by− age by alluvium (severe flooding during 1999) affects the bed in Mexico from Lower Tithonian siltstones of the Tamán Tithonian deposits. Cherty intercalations in grayish to darkish Formation cropping out along the Apulco River, Mazatepec, and more calcareous clayey limestones characterise the Puebla (Figs. 1, 2). The studied material was collected from Pimienta Formation (López Ramos 1979b: 315). Apulco section MT−2 (Villaseñor et al. 2003; López−Cabal− The new Apulco section MTQ crops out along the west lero et al. 2007; Villaseñor and Olóriz 2009) and the new bank of the Apulco River, close to the hydroelectric station MTQ section. VILLASEÑOR ET AL.—TITHONIAN SIMOCERATID AMMONOIDS FROM MEXICO 135 Apulco section (MT-2) Apulco section (MTQ) [covered] 40 39 38 37 PIMIENTA FM. 36 UPPER TITHONIAN 35 34a 34b 34c 33 32 31 30 29 28 -MT-Q14 -MT-Q13 27a -MT-Q12 27b -MT-Q11 27c 26 LOWER TITHONIAN TAMAN FORMATION LOWER TITHONIAN TAMAN FORMATION -MT-Q10 25 24 2m 23 2m 22b 22 21b 0m -MT-Q9 0m 21a [submerged] Pseudovolanoceras aesinense chignahuapense (Cantú-Chapa, 1990) Pseudovolanoceras aesinense limestone with fine (Meneghini, 1885) parallel lamination cherty horizon Pseudhimalayites steinmanni (Haupt, 1907) concretional silty limestone limestone siltstone calcareous siltstone Housaites butti ()Imlay, 1942 siltstone with small calcareous concretions perisphinctids Fig. 2. Stratigraphic sections with indication of precise records of Pseudovolanoceras aesinense (Meneghini, 1885) and Pseudovolanoceras aesinense chignahuapense (Cantú−Chapa, 1990) in the Apulco sections MT−2 and MTQ. Note the occurrence of other ammonites significant for biostratigraphy and correlation. Records of simoceratins from the Americas.—Precise in− have been reported with illustration, aside from some text cita− formation about the record of Lower Tithonian simoceratins tions. Krantz (1928) identified the southernmost record, from from the Americas is rare, and to date only four specimens Argentina, while the other three records were reported by doi:10.4202/app.2010.0030 136 ACTA PALAEONTOLOGICA
Load more

Recommended publications
  • Stratigraphic Constraints on the Late Jurassic–Cretaceous Paleotectonic Interpretations of the Placetas Belt in Cuba, in C
    Pszczo´łkowski, A., and R. Myczyn´ ski, 2003, Stratigraphic constraints on the Late Jurassic–Cretaceous paleotectonic interpretations of the Placetas belt in Cuba, in C. Bartolini, R. T. Buffler, and J. Blickwede, eds., The Circum-Gulf of Mexico and the Caribbean: Hydrocarbon habitats, basin 25 formation, and plate tectonics: AAPG Memoir 79, p. 545–581. Stratigraphic Constraints on the Late Jurassic–Cretaceous Paleotectonic Interpretations of the Placetas Belt in Cuba Andrzej Pszczo´łkowski Institute of Geological Sciences, Polish Academy of Sciences, Warszawa, Poland Ryszard Myczyn´ski Institute of Geological Sciences, Polish Academy of Sciences, Warszawa, Poland ABSTRACT he Placetas belt in north-central Cuba consists of Late Jurassic–Cretaceous rocks that were highly deformed during the Paleocene to middle Eocene T arc-continent collision. The Late Proterozoic marble and Middle Jurassic granite are covered by the shallow-marine arkosic clastic rocks of late Middle Jurassic(?) or earliest Late Jurassic(?) ages. These arkosic rocks may be older than the transgressive arkosic deposits of the Late Jurassic–earliest Cretaceous Con- stancia Formation. The Berriasian age of the upper part of the Constancia For- mation in some outcrops at Sierra Morena and in the Jarahueca area does not confirm the Late Jurassic (pre-Tithonian) age of all deposits of this unit in the Placetas belt. The Tithonian and Berriasian ammonite assemblages are similar in the Placetas belt of north-central Cuba and the Guaniguanico successions in western Cuba. We conclude that in all paleotectonic interpretations, the Placetas, Camajuanı´, and Guaniguanico stratigraphic successions should be considered as biogeographically and paleogeographically coupled during the Tithonian and the entire Cretaceous.
    [Show full text]
  • 06 Pavia.Pmd
    Bollettino della Società Paleontologica Italiana, 45 (2-3), 2006, 217-226. Modena, 15 gennaio 2007217 Lissoceras monachum (Gemmellaro), a ghost Ammonitida of the Tethyan Bathonian Giulio PAVIA G. Pavia, Dipartimento di Scienze della Terra, via Valperga Caluso 35, I-10124 Torino (Italy); [email protected] KEY-WORDS - Systematics, Ammonitida, Lissoceras, Bathonian, Tethys. ABSTRACT - L. monachum has been frequently recorded in the Upper Bajocian and Lower Bathonian, but references in literature differ in morphological details as they are based on a juvenile and poorly-preserved holotype. In addition, the type of L. monachum comes from a bed affected by taphonomical condensation mixing fossils from Early and Middle Bathonian times, i.e. the biochronological meaning of Gemmellaro’s taxon cannot be specified with biostratigraphic criteria from the type-locality. These references are here revised and refused on the basis of two topotypes recently sampled at Monte Erice in western Sicily, which allow a precise morphological definition of L. monachum by means of architectural and sutural characteristics. The only acceptable biostratigraphic datum comes from a Lower Bathonian specimen from southern France. The differences from L. ferrifex, L. magnum, and L. ventriplanum are discussed. Finally, the suture-line of topotype PU111502 of L. monachum and those specimens from the Upper Bajocian of the Venetian Alps, here named L. aff. monachum, support the phyletic relationships between L. ferrifex and L. magnum through transitional forms of L. monachum aged for the Tethyan Early Bathonian. RIASSUNTO - [Lissoceras monachum (Gemmellaro), un Ammonitida fantasma del Batoniano Tetideo] - L’ammonite Lissoceras monachum, della famiglia medio- e tardo-giurassica Lissoceratidae, risulta ripetutamente citata nella letteratura sistematica relativa al Baiociano superiore e al Batoniano inferiore.
    [Show full text]
  • Kimmeridgian (Late Jurassic) Cold-Water Idoceratids (Ammonoidea) from Southern Coahuila, Northeastern Mexico, Associated with Boreal Bivalves and Belemnites
    REVISTA MEXICANA DE CIENCIAS GEOLÓGICAS Kimmeridgian cold-water idoceratids associated with Boreal bivalvesv. 32, núm. and 1, 2015, belemnites p. 11-20 Kimmeridgian (Late Jurassic) cold-water idoceratids (Ammonoidea) from southern Coahuila, northeastern Mexico, associated with Boreal bivalves and belemnites Patrick Zell* and Wolfgang Stinnesbeck Institute for Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234, 69120 Heidelberg, Germany. *[email protected] ABSTRACT et al., 2001; Chumakov et al., 2014) was followed by a cool period during the late Oxfordian-early Kimmeridgian (e.g., Jenkyns et al., Here we present two early Kimmeridgian faunal assemblages 2002; Weissert and Erba, 2004) and a long-term gradual warming composed of the ammonite Idoceras (Idoceras pinonense n. sp. and trend towards the Jurassic-Cretaceous boundary (e.g., Abbink et al., I. inflatum Burckhardt, 1906), Boreal belemnites Cylindroteuthis 2001; Lécuyer et al., 2003; Gröcke et al., 2003; Zakharov et al., 2014). cuspidata Sachs and Nalnjaeva, 1964 and Cylindroteuthis ex. gr. Palynological data suggest that the latest Jurassic was also marked by jacutica Sachs and Nalnjaeva, 1964, as well as the Boreal bivalve Buchia significant fluctuations in paleotemperature and climate (e.g., Abbink concentrica (J. de C. Sowerby, 1827). The assemblages were discovered et al., 2001). in inner- to outer shelf sediments of the lower La Casita Formation Upper Jurassic-Lower Cretaceous marine associations contain- at Puerto Piñones, southern Coahuila, and suggest that some taxa of ing both Tethyan and Boreal elements [e.g. ammonites, belemnites Idoceras inhabited cold-water environments. (Cylindroteuthis) and bivalves (Buchia)], were described from numer- ous localities of the Western Cordillera belt from Alaska to California Key words: La Casita Formation, Kimmeridgian, idoceratid ammonites, (e.g., Jeletzky, 1965), while Boreal (Buchia) and even southern high Boreal bivalves, Boreal belemnites.
    [Show full text]
  • Tithonian) Ammonites from the Spit! Shales in Western Zanskar(Nw Himalayas
    Riv. It. Paleont. Strat. pp. 461-486 tav. 22-24 Febbraio 1991 UPPERJURASSIC (TITHONIAN) AMMONITES FROM THE SPIT! SHALES IN WESTERN ZANSKAR(NW HIMALAYAS) F. OLORIZ*& A. TINTORI** Key-word s: Paleoecology, Biostratigraphy, Ammonites, Upper Jurassic, Zanskar (NW Himalayas). Abstract. A description is given of the ammonites collected during the Italian expedition to the Zanskar region of the NW Himalayasin 1984 . The paleontological analysis is made in the context of a depositional and ecological model proposed for Spiti Shales fades. The genera Uhligites, "Vi-rgatosphinctes", Aulacosphinctesand Parapallasicerasare identified. An upper -to uppermost Lower Tithonian age is assigned for the highest levels of the Spiti Shales Fm. in the sector examined, although it may be possible that the extreme base of the Upper Tithonian is alsorepresented. Introduct ion and geological setting. This paper deals with a small ammonite fauna found near Sneatze (Western Zan­ skar) in the famous unit of the Spiti Shales. During the Italian geological expedition in Zanskar in the summer of 1984, one of us (A.T.) surveyed in particular the Jurassic units Qadoul et al., 1985; Gaetani et al., 1986). As regards the Mesozoic, most of the expedition took place in the Zangla Nappe (Baud et al., 1984), but a few observations were made also along the front of the Zum­ lung Nappe (Baud et al., 1984). Three main lithostratigraphic units are distinguishable between Ringdom Gompa and Tantak, even though they are often incompletely present as a result of the heavy tectonics of the area (Gaetani et al., 1985). The Kioto Limestone is uppermost Triassic-Late Liassic in age (Gaetani et al., 1986) and is rather poor in mac­ rofossils there.
    [Show full text]
  • Cuesta Del Cura Limestone
    BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA VOL. 49, PP. 1651-1694. 7 PLS., 6 FIGS. NOVEM BER 1, 1938 STUDIES OF THE MEXICAN GEOSYNCLINE BY EALPH W. IMLAY CONTENTS Page Abstract....................................................................................................................................... 1652 Introduction............................................................................................................................... 1652 Acknowledgments..................................................................................................................... 1654 Earlier investigations............................................................................................................... 1654 Geography................................................................................................................................... 1654 Topography and drainage.............................................................................................. 1654 Culture................................................................................................................................ 1655 Sedimentary rocks..................................................................................................................... 1657 General discussion.......................................................................................................... 1657 Jurassic system................................................................................................................. 1657 Zuloaga
    [Show full text]
  • Redalyc.Upper Jurassic Ammonites and Bivalves from the Cucurpe
    Revista Mexicana de Ciencias Geológicas ISSN: 1026-8774 [email protected] Universidad Nacional Autónoma de México México Villaseñor, Ana Bertha; González Léon, Carlos M.; Lawton, Timothy F.; Aberhan, Martin Upper Jurassic ammonites and bivalves from the Cucurpe Formation, Sonora (Mexico) Revista Mexicana de Ciencias Geológicas, vol. 22, núm. 1, 2005, pp. 65-87 Universidad Nacional Autónoma de México Querétaro, México Available in: http://www.redalyc.org/articulo.oa?id=57222107 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 Revista Mexicana de Ciencias Geológicas,Upper v. 22, Jurassic núm. 1, ammonites 2005, p. 65-87 and bivalves from Sonora 65 Upper Jurassic ammonites and bivalves from the Cucurpe Formation, Sonora (Mexico) Ana Bertha Villaseñor1,*, Carlos M. González-León2, Timothy F. Lawton3, and Martin Aberhan4 1 Departamento de Paleontología, Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México, D. F., Mexico. 2 Estación Regional del Noroeste, Instituto de Geología, Universidad Nacional Autónoma de México, 83000 Hermosillo, Sonora, Mexico. 3 Department of Geological Sciences, New Mexico State University, Las Cruces, NM 88003, USA. 4 Museum für Naturkunde, Zentralinstitut der Humboldt-Universität zu Berlin, Institut für Paläontologie, Invalidenstr. 43, D-10115 Berlin, Germany. * [email protected] ABSTRACT Four new molluscan assemblages from north-central Sonora indicate that the Cucurpe Formation ranges in age from late Oxfordian to early Tithonian. These assemblages extend the known paleogeographic range of Late Jurassic Tethyan fossil groups several hundred km to the northwest and improve correlation of Upper Jurassic strata in northern Mexico.
    [Show full text]
  • In the Lower Tithonian of Sierra Del Rosario (Western Cuba)
    Atti II Conv. Int. Pallini 401-403 PP Simocosmoceras in Western Cuba F.E.A. Pergola, 87 et alii cur. 1 tav 4 figg. Simocosmoceras Spath (Perisphinctidae, Ammonitina) in the Lower Tithonian of Sierra del Rosario (Western Cuba) RYSZARD MYCZYNSKI Insitute of Geological Sciences, Polish Academy of Sciences, Al. Zwirki i Wigury 93, 02-089 Warszawa, Poland RIASSUNTO E segnalata per la prima volta la presenza di ammoniti del genere Simocosmoceras Spath 1925 nel Titonico inferiore della Siena del Ro­ sario (provincia di Pinar del Rio - Cuba occidentale). Queste ammoni­ ti sono state trovate nella formazione di Artemisa, datata al Giurassi­ co superiore e Cretaceo inferiore, nella sezione di Lorna Ferretero. Le ammoniti cubane del genere Simocosmoceras Spath, 1925 sono diverse dalle specie conosciute di questo genere. La presenza di ammo­ niti del genere Simocosmoceras Spath 1925 nel Titonico inferiore di Cuba è un argomento a favore dell'efficacia della via proto-Atlantica per la migrazione di faune ad ammoniti durante il Giurassico ("Hi­ spanic corridor" sensu Westermann, 1984). ABSTRACT The occurrence of the ammonite genus Simocosmoceras Spath, 1925 Fig. f - Location map of the study area in the Sierra del Rosario, Pi­ in the Lower Tithonian of Sierra del Rosario (Pinar del Rio province, nar del Rio province, western Cuba. western Cuba) is reported for the first time. This genus was found in the Artemisa Formation, dated at the Upper Jurassic and Lower Creta­ ceous, in the Lorna Ferretero section. Cuban ammonites of the genus Monte Acuto (Gruppo del Monte Catria, Marche, Ita­ Simocosmoceras Spath, 1925 are different from the species of this ge­ ly).
    [Show full text]
  • Proceedings of the United States National Museum
    NOTES ON THE AGE OF THE CONTINENTAL TRIASSIC BEDS IN NORTH AMERICA, WITH REMARKS ON SOME FOSSIL VERTEBRATES By F, R. von Huene Of the University of Tilbingen, Germany For paleontological purposes, it is sometimes unfortunate that the continental Triassic formations of North America can not in all of their parts be properly incorporated in the standard strati- graphic scheme. The standard scheme is, of course, based on marine fossils, and in North America, as in Europe, transition beds between continental and marine strata are missing. This is the cause of the difficulty. In the present paper the author has endeavored to pre- sent a generalized classification of the vertebrate-bearing Triassic beds of North America. The Triassic deposits near the Atlantic coast and the Red Beds in the central and western regions have a different aspect. There- fore it will be best to treat them separately. I. Central and western regions.—The Triassic Red Beds of these regions are the continuation of and close of a large series beginning at some places with the older Carboniferous, at others with the Permian. Though there is much local variation, the structure and color of the rocks is remarkably uniform. Fossil horizons are rare and it is therefore not easy to compare particular beds that are far distant from one another. The thickness of the Triassic is in gen- eral several hundred meters; the lower limit is not accurately fixed and the upper is sometimes badly defined. Whole divisions may be missing, and often it is not possible to detect such a hiatus by a clearly observed discordance.
    [Show full text]
  • A Comparison of the Ammonite Faunas of the Antarctic Peninsula and Magallanes Basin
    J. geol. Soc. London, Vol. 139, 1982, pp. 763-770, 1 fig, 1 table. Printed in Northern Ireland A comparison of the ammonite faunas of the Antarctic Peninsula and Magallanes Basin M. R. A. Thomson SUMMARY: Ammonite-bearingJurassic and Cretaceous sedimentary successions are well developed in the Antarctic Peninsula and the Magallanes Basin of Patagonia. Faunas of middle Jurassic-late Cretaceous age are present in Antarctica but those of Patagonia range no earlier than late Jurassic. Although the late Jurassic perisphinctid-dominated faunas of the Antarctic Peninsulashow wide-ranging Gondwana affinities, it is not yet possible to effect a close comparison with faunas of similar age in Patagonia because of the latter's poor preservation and our scant knowledge of them. In both regions the Neocomian is not well represented in the ammonite record, although uninterrupted sedimentary successions appear to be present. Lack of correspondence between the Aptian and Albian faunas of Alexander I. and Patagonia may be due to major differences in palaeogeographical setting. Cenomanian-Coniacian ammonite faunas are known only from Patagonia, although bivalve faunas indicate that rocks of this age are present in Antarctica. Kossmaticeratid faunas mark the late Cretaceous in both regions. In Antarcticathese have been classified as Campanian, whereas in Patagonia it is generally accepted, perhaps incorrectly, that these also range into the Maestrichtian. Fossiliferous Jurassic and Cretaceous marine rocks are rize first those of the Antarctic Peninsula and then to well developedin theAntarctic Peninsula, Scotia compare them with those of Patagonia. Comparisons Ridge andPatagonia (Fig. 1A).In Antarcticathese between Antarctic ammonite faunas and other Gond- rocks are distributed along the western and eastern wana areas wereoutlined by Thomson (1981a), and margins of theAntarctic Peninsula, formerly the the faunas of the marginal basin were discussed in magmatic arc from which the sediments were derived.
    [Show full text]
  • Double Alignments of Ammonoid Aptychi from the Lower Cretaceous of Southeast France: Result of a Post−Mortem Transport Or Bromalites?
    Double alignments of ammonoid aptychi from the Lower Cretaceous of Southeast France: Result of a post−mortem transport or bromalites? STÉPHANE REBOULET and ANTHONY RARD Reboulet, S. and Rard, A. 2008. Double alignments of ammonoid aptychi from the Lower Cretaceous of Southeast France: Result of a post−mortem transport or bromalites? Acta Palaeontologica Polonica 53 (2): 261–274. A new preservation of aptychi is described from the Valanginian limestone−marl alternations of the Vergol section (Drôme), located in the Vocontian Basin (SE France). Aptychi are arranged into two parallel rows which are generally 50 mm in length and separated by 4 mm. The alignments are very often made by entire aptychi (around 10 mm in length), oriented following their harmonic margin. Aptychi show the outside of valve to the viewer: they are convex−up. This fos− silization of aptychi is successively interpreted as the result of post−mortem transport by bottom currents (taphonomic− resedimentation process) or the residues (bromalites: fossilized regurgitation, gastric and intestinal contents, excrement) from the digestive tract of an ammonoid−eater (biological processes). Both the parallel rows of aptychi are more likely in− terpreted as a coprolite (fossil faeces) and they could be considered as both halves (hemi−cylindrical in shape) of the same cylindrical coprolite which would have been separated in two parts (following the long axis) just after the animal defe− cated. Considering this hypothesis, a discussion is proposed on the hypothetical ammonoid−eater responsible for them. Key words: Ammonoidea, taphonomy, aptychus, coprolite, predation, Valanginian, Cretaceous, France. Stéphane Reboulet [stephane.reboulet@univ−lyon1.fr], Université de Lyon, (UCBL1, La Doua), UFR des Sciences de la Terre, CNRS−UMR 5125 PEPS, Bâtiment Géode, 2 Rue Raphaël Dubois, 69622 Villeurbanne cedex, France; Anthony Rard [anthony.rard@cc−thouarsais.fr], Centre d'interprétation géologique du Thouarsais, Réserve Naturelle Géologique du Toarcien, Les Ecuries du Château, 79100 Thouars, France.
    [Show full text]
  • A Late Valanginian Mediterranean Ammonoid Fauna from the Lunz ­Nappe (Northern Calcareous Alps; Lower Austria)
    Austrian Journal of Earth Sciences Vienna 2016 Volume 109/2 252 - 261 DOI: 10.17738/ajes.2016.0019 A Late Valanginian Mediterranean ammonoid fauna from the Lunz Nappe (Northern Calcareous Alps; Lower Austria) Alexander LUKENEDER Geological-Palaeontological Department, Natural History Museum, Burgring 7, A-1010 Wien, Austria; [email protected] KEYWORDS Tethyal ammonoid assemblage; Early Cretaceous (Late Valanginian); Perchtoldsdorf Syncline; Lunz Nappe; Northern Calcareous Alps Abstract Early Cretaceous ammonoids were collected from the Northern Calcareous Alps in the southeasternmost part of the Lunz Nappe (Perchtoldsdorf Syncline) near Vienna. The cephalopod assemblage, the easternmost Early Cretaceous assemblage from the Northern Calcareous Alps, derives from the Rossfeld Formation, indicating a mid Late Valanginian age (Neocomites peregrinus Zone). The deposition of the sandy limestones and marly limestones in this interval occurred during unstable environmental condi- tions which led to a preserved autochthonous fauna comprising additional transported allochthonous ammonoid specimens. The ammonoid fauna yields 6 different genera, each apparently represented by 1-2 species. Ammonitina are the most frequent components (Haploceras, Neocomites, Jeanthieuloyites), followed by the lytoceratids (Lytoceras), the phylloceratids (Phylloceras), and ancyloceratids (Himantoceras). The cephalopod fauna consists of Mediterranean elements dominated by neocomitids. Unterkreide-Ammonoideen der Nördlichen Kalkalpen werden aus dem südöstlichsten Teil der Lunzer Decke (Perchtoldsdorf Mulde) beschrieben. Die Cephalopoden Fauna der Rossfeld-Formation zeigt unteres Ober-Valanginium an (Neocomites peregrinus Zone). Die sandigen und mergeligen Kalke dieses Abschnitts lagerten sich während instabiler Umweltbedingungen ab, welche zu einer autochthonen Fauna mit teilweise transportierten allochthonen Ammoniten führten. Die Ammonoideen-Fauna zeigt 6 unter- schiedliche Gattungen, von welchen jede durch 1-2 Arten vertreten ist.
    [Show full text]
  • Print This Article
    Volumina Jurassica, 2013, Xi: 97–146 Ammonites from the Oxfordian-Kimmeridgian boundary and the Lower–Upper Kimmeridgian of Kachchh, western India Dhirendra K. PANDEY 1, Matthias ALBERTI 2, Franz T. FÜRSICH 3, Ewa Głowniak 4, Federico olóriz 5 Key words: ammonites, oxfordian-kimmeridgian, kachchh, india. Abstract. Several new specimens of ammonites from the Oxfordian and Kimmeridgian of Kachchh, western India, are described and il- lustrated. The Oxfordian ammonites ?Subdiscosphinctes Malinowska, Perisphinctes Waagen, Dichotomoceras Buckman, and ?Larche­ ria Tintant, all from Bharodia in the wagad Uplift, enable tentative biochronostratigraphic correlations with the uppermost Middle oxfordian up to the lower Upper Oxfordian of the unified Submediterranean zonation, whereas the Kimmeridgian ammonites Streblites Hyatt, “Orthosphinctes” Schindewolf, Torquatisphinctes Spath, Pachysphinctes Dietrich, Katroliceras Spath, Aspidoceras zittel, and Schaireria Checa reconfirm a stratigraphic gap embracing incompletely known parts of the uppermost oxfordian and the lower kimmeridgian as known from the ammonite records of the kachchh Mainland of the kachchh Basin. IntrodUctIon kachchh Basin, which mainly concentrated on the Oxfordian part of the succession, showed that the ammonite record of Cephalopods of the kachchh Basin in western india the area is not yet known comprehensively. During the sur- (Fig. 1) have been studied for more than a century beginning veys more than 800 cephalopods were collected with high with the prominent monographs of waagen (1873–1875) stratigraphic resolution, and additional specimens collected and Spath (1927–1933). Since then major progress has been by the late John H. Callomon in the 1990s were studied at achieved in understanding the litho- and biostratigraphy of the oxford University Museum of natural History.
    [Show full text]