CENOZOIC PALINSPASTIC RECONSTRUCTION, PALEOGEOGRAPHTC EVOLUTION AND HYDROCARBON SETTING OF THE NORTHERN MARGIN OF SOUTH AMERICA

Author(s):  
JAMES L. PINDELL ◽  
ROGER HIGGS ◽  
JOHN F. DEWEY
1914 ◽  
Vol 1 (2) ◽  
pp. 61-64
Author(s):  
J. W. Gregory

The special interest of the island of South Georgia depends on the evidence it promises as to the geological history of that part of the Southern Ocean which lies south of the South Atlantic. According to the well-known views of Professor Suess, South Georgia is on a continuation of the mountain line of the Andes, which at the southern end of South America bends eastward along the northern margin of Drake's Sea and continues 30° to the east, where it turns southward; it completes a great horseshoe-shaped course by passing through South Georgia and returning westward through the South Orkneys to Grahamland.


Fossil Record ◽  
2002 ◽  
Vol 5 (1) ◽  
pp. 155-206 ◽  
Author(s):  
G. C. Young ◽  
J. M. Moody

A new Devonian fossil fish fauna from the region of Caño Colorado between the Rio Palmar and Rio Socuy, Sierra de Perijá, Venezuela, comes from two localities and several horizons within the Campo Chico Formation, dated on plants and spores as Givetian-Frasnian in age. Placoderms are most common, with the antiarch <i>Bothriolepis perija</i> n. sp., showing affinity with species from the Aztec fish fauna of Victoria Land, Antarctica. A second antiarch, <i>Venezuelepis mingui</i> n.g. n.sp., is also closely related to an Antarctic species, which is reassigned to this new genus. Fragmentary remains of a phyllolepid placoderm show similarity to the genus <i>Austrophyllolepis</i> from southeastern Australia. Chondrichthyan spines are provisionally referred to the Antarctilamnidae, and acanthodian remains include spines of the widespread taxon <i>Machaeracanthus</i>. Osteichthyans are represented by osteolepid and dipnoan scales and teeth, and scales lacking cosmine which may belong to another major taxon. This fauna has provided the first Devonian record from South America of three major fish groups: antiarch and phyllolepid placoderms, and dipnoans. These are widely distributed on most other continents. Although invertebrates and plants from the same sequence closely resemble those of eastern North America, the endemic elements in the fish fauna indicate Gondwana affinities. Phyllolepid placoderms are common in Givetian-Frasnian strata of Australia and Antarctica, but are only known from the Famennian in the Northern Hemisphere. The new phyllolepid occurrence extends their range across the northern margin of Palaeozoic Gondwana. The age and affinities of this new fish fauna are consistent with a model of biotic dispersal between Gondwana and Euramerica at or near the Frasnian-Famennian boundary. A narrow marine barrier separating northern and southern continental landmasses is indicated, in contrast to the wide equatorial ocean for the Late Devonian postulated from palaeomagnetic data. <br><br> Es wird eine neue devonische Fischfauna aus dem Gebiet zwischen Caño Colorado und Rio Socuy, Sierra de Perijá, beschrieben. Die Funde stammen aus zwei Lokalitäten und mehreren Horizonten innerhalb der Campo Chico Formation, die auf Grundlage von Untersuchungen der Pflanzen- und Sporenfunde dem Zeitabschnitt Givetium-Frasnium zugeordnet werden. Placodermen sind durch den Antiarchen <i>Bothriolepis perija</i> n. sp. häufig vertreten. Sie sind mit Arten der Aztec-Fischfauna von Viktoria Land, Antarktis, verwandt. Ein zweiter Antiarche, der <i>Venezuelepis mingui</i> n. g. n. sp. ist eng mit einer Spezies aus der Antarktis verwandt, die ebenfalls dieser neuen Gattung zugeschrieben wird. Fragmentarische Reste eines phyllolepiden Placodermen weisen Ähnlichkeiten mit der Gattung <i>Austrophyllolepis</i> aus dem Südosten Australiens auf. Wirbel eines Chondrichthyer werden vorläufig den Antarctilamnidae zugeschrieben. Acanthodir-Reste schließen das weitverbreitete Taxon <i>Machaeracanthus</i> ein. Osteichthyer sind durch Schuppen und Zähne osteolepider Sarcopterygier und Dipnoi vertreten. Andere Schuppen, denen die Cosminschicht fehlt, gehören vermutlich zu einem anderen Haupttaxon. Damit ist durch diese Fauna der erste Nachweis für das Vorkommen der drei Hauptfischgruppen Antiarchi, phyllolepide Placodermi und Dipnoi im Devon Südamerikas erbracht. Sie sind auch auf den meisten anderen Kontinenten weit verbreitet. Obwohl Invertebraten und Pflanzen aus derselben Zeit sehr denen aus dem Osten Nordamerikas ähneln, weisen die endemischen Elemente in der Fischfauna auf eine Affinität zu Gondwana hin. Phyllolepide Placodermen sind im Givetium-Frasnianium Australiens verbreitet, aber erst aus dem Famennium in der Nordhemisphere bekannt. Das Auftreten eines neuen Phyllolepiden weitet den Vorkommensbereich über die nördliche Linie des paläozoischen Gondwanas hinaus aus. Alter und Verwandtschaftsbeziehungen dieser neuen Fischfauna stimmen mit dem Modell der biotischen Verbreitung zwischen Gondwana und Euramerika an bzw. nah an der Frasnium-Famennium-Grenze überein. Es gibt Hinweise für eine die nördlichen und südlichen Landmassen trennende schmale Meerenge. Dies steht im Gegensatz zur Annahme eines weiten äquatorialen Ozeans im späten Devons, die sich auf palaeomagnetische Daten stützt. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.20020050111" target="_blank">10.1002/mmng.20020050111</a>


2010 ◽  
Vol 23 (10) ◽  
pp. 2671-2685 ◽  
Author(s):  
Benjamin R. Lintner ◽  
J. David Neelin

Abstract The edges or margins of tropical convective zones are hypothesized to be sensitive to low-level inflow conditions. The present study evaluates where and to what extent convective margin variability is sensitive to low-level inflow variability using observed precipitation and reanalysis wind and total precipitable water data over the tropical South America–Atlantic sector in austral summer. Composite analysis based on an inflow measure defined by projecting low-level monthly-mean atmospheric boundary layer (ABL) or lower free troposphere (LFT) winds onto either mean horizontal precipitation or precipitable water gradients shows widespread contraction of the edges of convection zones in the direction of stronger convection for anomalously strong low-level inflow; such behavior is consistent with enhanced import of relatively dry air along the edges of convection zones. However, the distinction between ABL and LFT winds may be significant regionally, for example, along the Atlantic ITCZ’s northern margin. Back trajectory analysis is employed to estimate source regions of low-level air masses arriving at margin points over time scales (2–4 days) during which low-level air masses are expected to retain some memory of initial moisture conditions while also undergoing diabatic modification. Probability distribution functions of mean precipitation values encountered along trajectories facilitate objective quantification of the frequency with which trajectories approach the margin from drier areas outside the convection zone. While margin points in the ABL are strongly dominated by inflow (i.e., trajectories originating outside of the convection zone), points in the LFT may show inflow, outflow, or mixed inflow–outflow conditions. LFT locations dominated by inflow trajectories generally correspond to regions with composites exhibiting the clearest signatures of LFT wind variability on precipitation.


2014 ◽  
Vol 41 (1) ◽  
pp. 113-123 ◽  
Author(s):  
Gary M. Fellers

Rollo Howard Beck (1870–1950) was a professional bird collector who spent most of his career on expeditions to the Channel Islands off southern California, the Galápagos Islands, South America, the South Pacific, and the Caribbean. Some of the expeditions lasted as long as ten years during which time he and his wife, Ida, were often working in primitive conditions on sailing vessels or camps set up on shore. Throughout these expeditions, Beck collected specimens for the California Academy of Sciences, the Museum of Vertebrate Zoology at Berkeley (California), the American Museum of Natural History, and the Walter Rothschild Museum at Tring, England. Beck was one of the premier collectors of his time and his contributions were recognized by having 17 taxa named becki in his honor. Of these taxa, Beck collected 15 of the type specimens.


2017 ◽  
Vol 44 (1) ◽  
pp. 122-129 ◽  
Author(s):  
A. Padfield

Charles Waterton was the eccentric “Lord of Walton Hall” near Wakefield in Yorkshire. His Wanderings in South America was first published in 1826; translated into French, German and Spanish, it was a best seller. He brought back wourali used by the Macoushi natives of British Guiana (now Guyana) for killing prey; there is a piece of it in the Wakefield Museum. This paper traces the history of wourali which paralyses its victims; its attempted medical use for rabies and tetanus and, though different from curare, its belated use in modern anaesthesia.


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