The first record of fossil penguins from East Antarctica

2012 ◽  
Vol 25 (3) ◽  
pp. 397-408 ◽  
Author(s):  
Piotr Jadwiszczak ◽  
Krzysztof P. Krajewski ◽  
Zinaida Pushina ◽  
Andrzej Tatur ◽  
Grzegorz Zieliński
Keyword(s):  
Late Miocene ◽  
Middle Miocene ◽  
First Record ◽  
East Antarctica ◽  
X Ray Diffraction ◽  
Diagenetic Alteration ◽  
Strontium Isotope Stratigraphy ◽  
Extant Genus ◽  
Isotope Stratigraphy ◽  
The Antarctic

AbstractThis paper presents the first fossil penguin from East Antarctica, and the only one known south of the Antarctic Circle. It is represented by two well-preserved elements of the wing skeleton, humerus and radius, obviously assignable to the extant genus Spheniscus. They were found in the glaciomarine succession of the Fisher Bench Formation (Fisher Massif, Prince Charles Mountains, Mac. Robertson Land), which was dated using Strontium Isotope Stratigraphy to be Late Miocene in age (10.2 Ma). They are only slightly younger than the oldest remains undoubtedly attributable to this taxon. The X-ray diffraction and Fourier Transform Infrared Spectroscopy indicate diagenetic alteration of the original bone bioapatite under dominantly marine conditions. The Late Miocene was a period of ice margin retreat and marine incursion into the Lambert embayment that followed Middle Miocene cooling of the Antarctic climate. The fossils strongly suggest that variable climatic and environmental conditions in East Antarctica may have been an important factor in the evolution of penguins there during the Neogene.

scholarly journals On the reconciliation of biostratigraphy and strontium isotope stratigraphy of three southern Californian Plio-Pleistocene formations

2020 ◽  
Vol 133 (1-2) ◽  
pp. 100-114
Author(s):  
Alexandra J. Buczek ◽  
Austin J.W. Hendy ◽  
Melanie J. Hopkins ◽  
Jocelyn A. Sessa
Keyword(s):  
San Diego ◽  
Isotope Ratios ◽  
Strontium Isotope ◽  
Granitic Rocks ◽  
Early Pleistocene ◽  
X Ray Diffraction ◽  
Diagenetic Alteration ◽  
Strontium Isotope Stratigraphy ◽  
Isotope Stratigraphy ◽  
Flow Through

Abstract The San Diego Formation, Pico Formation, Careaga Sandstone, and Foxen Mudstone of southern California are thought to be late Pliocene to early Pleistocene; however, numerical ages have not been determined. Following assessment of diagenetic alteration via multiple methods including scanning electron microscopy (SEM), X-ray diffraction (XRD), and minor elemental concentrations, we attempted to use strontium isotope stratigraphy to assign numerical ages. Using aragonitic fossils, we obtained ages of 2.0–1.85 Ma for the Careaga Sandstone and 2.0–1.75 Ma for the uppermost Foxen Mudstone, consistent with biostratigraphic work suggesting a Gelasian age for the Careaga Sandstone. Isotope ratios for aragonitic and calcitic fossils from the Pico Formation were poorly constrained, with the exception of one bed yielding ages of 5.1–4.3 Ma. Isotope ratios from the San Diego Formation were also inconsistent within beds, with the exception of two isolated outcrops that yielded ages of 5.0–4.5 Ma and 4.5–2.8 Ma, respectively. The age estimates for the Pico and San Diego Formations are older than most ages inferred from biostratigraphy. Noting that some aragonitic specimens from the San Diego Formation yielded isotope ratios indicative of ages as old as 19.4 Ma, we propose that some outcrops have been affected by diagenesis caused by groundwater flow through proximal granitic rocks and input from detrital sediment. Although we recommend that strontium isotope results for the Pico and San Diego Formations be interpreted with caution, the ages of the uppermost Foxen Mudstone and Careaga Sandstone can be confidently placed within the early Pleistocene.

scholarly journals The First Appearance of Hucho (Salmonidae) in the Fossil Record of Eastern Europe

2015 ◽  
Vol 49 (5) ◽  
pp. 413-420 ◽  
Author(s):  
О. М. Kovalchuk
Keyword(s):  
Eastern Europe ◽  
Late Pleistocene ◽  
Late Miocene ◽  
Fossil Record ◽  
Middle Miocene ◽  
Fossil Remains ◽  
Extant Genus ◽  
Geological Past ◽  
Late Neogene ◽  
Southern Ukraine

Until now, fossil remains of Hucho Gunther, 1866 are known only from the Oligocene - middle Miocene strata of Baikal Russia, and from the late Pleistocene of Germany. New specimens, now identified as Hucho sp., come from the late Miocene of southern Ukraine. Numerous fragments of opercular bones and jaw teeth, morphologically similar to those in the extant genus Hucho, were found in Kubanka 2, Cherevychnoe 3, Tretya Krucha localities and dated by the late Sarmatian - early Maeotian (10-8 Ma). Th ese remains document the first appearance of huchen in geological past of Europe, filling in gap in distribution of this genus during the late Neogene, and throw light upon its biogeographical history.

Neogene Pectinidae (Bivalvia) of tribe Chlamydini Teppner, 1922 in Patagonia (Argentina):ZygochlamysIhering, 1907 and three new genera

2018 ◽  
Vol 93 (2) ◽  
pp. 312-336 ◽  
Author(s):  
María B. Santelli ◽  
Claudia J. del Río
Keyword(s):  
Late Miocene ◽  
Type Species ◽  
Antarctic Circumpolar Current ◽  
Middle Miocene ◽  
New Genus ◽  
Early Miocene ◽  
New Genera ◽  
Early Pliocene ◽  
Circumpolar Current ◽  
The Antarctic

AbstractZygochlamysIhering, 1907 is revised and three new genera of tribe Chlamydini are named: the monospecific early Miocene generaPixiechlamysnew genus (type species:Pecten quemadensisIhering, 1897) andChokekenian. gen. (type species:Zygochlamys nicolasiMorra, 1985), and the late Miocene–early PlioceneMoirechlamysn. gen., containingPecten actinodesSowerby, 1846 (type species) andChlamys auroraeFeruglio, 1954.Zygochlamysis restricted to includeZ. geminata(Sowerby, 1846) (type species),Z. jorgensisIhering, 1907, andZ. sebastianiMorra, 1985. The present analysis increases the biostratigraphic usefulness of the group and improves taxonomic knowledge of the Neogene molluscan assemblages defined previously for Patagonia.Zygochlamys geminatais confined to the latest Oligocene–early Miocene interval of the Austral Basin of Patagonia (Argentina) and to the early Miocene of Chile,Z. jorgensisis restricted to the early to middle Miocene of the Golfo San Jorge and northern Austral Basins, andMoirechlamysn. gen., the most widespread genus, occurs in the late Miocene–early Pliocene of the Austral, Golfo San Jorge, Valdés, and Colorado basins. All these genera are endemic to southern South America;Zygochlamysis not related to other circumpolar genera such asAustrochlamysJonkers, 2003 orPsychrochlamysJonkers, 2003, rejecting its dispersal in the Antarctic Circumpolar Current, as has been proposed previously.UUID:http://zoobank.org/55d7ea85-5ec5-477a-9ede-5d3d795b75b5

Strontium Isotope Stratigraphy and the thermophilic fossil fauna from the middle Miocene of the East Pisco Basin (Peru)

2020 ◽  
Vol 97 ◽  
pp. 102399 ◽  
Author(s):  
Giulia Bosio ◽  
Elisa Malinverno ◽  
Alberto Collareta ◽  
Claudio Di Celma ◽  
Anna Gioncada ◽  
...  
Keyword(s):  
Middle Miocene ◽  
Strontium Isotope ◽  
Strontium Isotope Stratigraphy ◽  
Isotope Stratigraphy

scholarly journals Mass balance of the Antarctic ice sheet 1992–2016: reconciling results from GRACE gravimetry with ICESat, ERS1/2 and Envisat altimetry

2021 ◽  
pp. 1-27
Author(s):  
H. Jay Zwally ◽  
John W. Robbins ◽  
Scott B. Luthcke ◽  
Bryant D. Loomis ◽  
Frédérique Rémy
Keyword(s):  
Mass Balance ◽  
Antarctic Peninsula ◽  
East Antarctica ◽  
Mantle Material ◽  
West Antarctica ◽  
Mantle Viscosity ◽  
Grounding Line ◽  
The Antarctic ◽  
Total Gain

Abstract GRACE and ICESat Antarctic mass-balance differences are resolved utilizing their dependencies on corrections for changes in mass and volume of the same underlying mantle material forced by ice-loading changes. Modeled gravimetry corrections are 5.22 times altimetry corrections over East Antarctica (EA) and 4.51 times over West Antarctica (WA), with inferred mantle densities 4.75 and 4.11 g cm−3. Derived sensitivities (Sg, Sa) to bedrock motion enable calculation of motion (δB0) needed to equalize GRACE and ICESat mass changes during 2003–08. For EA, δB0 is −2.2 mm a−1 subsidence with mass matching at 150 Gt a−1, inland WA is −3.5 mm a−1 at 66 Gt a−1, and coastal WA is only −0.35 mm a−1 at −95 Gt a−1. WA subsidence is attributed to low mantle viscosity with faster responses to post-LGM deglaciation and to ice growth during Holocene grounding-line readvance. EA subsidence is attributed to Holocene dynamic thickening. With Antarctic Peninsula loss of −26 Gt a−1, the Antarctic total gain is 95 ± 25 Gt a−1 during 2003–08, compared to 144 ± 61 Gt a−1 from ERS1/2 during 1992–2001. Beginning in 2009, large increases in coastal WA dynamic losses overcame long-term EA and inland WA gains bringing Antarctica close to balance at −12 ± 64 Gt a−1 by 2012–16.

scholarly journals An Assessment of ERA5 Reanalysis for Antarctic Near-Surface Air Temperature

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 217
Author(s):  
Jiangping Zhu ◽  
Aihong Xie ◽  
Xiang Qin ◽  
Yetang Wang ◽  
Bing Xu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Antarctic Peninsula ◽  
Austral Summer ◽  
Correlation Coefficients ◽  
East Antarctica ◽  
West Antarctica ◽  
Austral Spring ◽  
Reanalysis Dataset ◽  
Near Surface ◽  
The Antarctic

The European Center for Medium-Range Weather Forecasts (ECMWF) released its latest reanalysis dataset named ERA5 in 2017. To assess the performance of ERA5 in Antarctica, we compare the near-surface temperature data from ERA5 and ERA-Interim with the measured data from 41 weather stations. ERA5 has a strong linear relationship with monthly observations, and the statistical significant correlation coefficients (p < 0.05) are higher than 0.95 at all stations selected. The performance of ERA5 shows regional differences, and the correlations are high in West Antarctica and low in East Antarctica. Compared with ERA5, ERA-Interim has a slightly higher linear relationship with observations in the Antarctic Peninsula. ERA5 agrees well with the temperature observations in austral spring, with significant correlation coefficients higher than 0.90 and bias lower than 0.70 °C. The temperature trend from ERA5 is consistent with that from observations, in which a cooling trend dominates East Antarctica and West Antarctica, while a warming trend exists in the Antarctic Peninsula except during austral summer. Generally, ERA5 can effectively represent the temperature changes in Antarctica and its three subregions. Although ERA5 has bias, ERA5 can play an important role as a powerful tool to explore the climate change in Antarctica with sparse in situ observations.

Tupinambine teiids from the middle Miocene of north-western Patagonia (Argentina)

2008 ◽  
Vol 29 (3) ◽  
pp. 425-431 ◽  
Author(s):  
Santiago Brizuela ◽  
Adriana María Albino
Keyword(s):  
Geographical Distribution ◽  
Middle Miocene ◽  
First Record ◽  
South American ◽  
The South ◽  
North Western

Abstract Remains of teiids assignable to the Tupinambinae (Tupinambis sp. or Crocodilurus sp.) are here described from the middle Miocene Collón Curá Formation at Cañadón del Tordillo, in Neuquén province, Argentina. No tupinambine species presently inhabits the region of the fossil locality. The fossils represent the westernmost distribution of fossil tupinambine teiids in Patagonia, enlarging the known geographical distribution of the teiids through the Miocene in a longitudinal range. Also, they constitute the first record of lizards from the Colloncuran SALMA, partially filling the record of tupinambine teiids for the South American Miocene.

Estimation of turbulent heat fluxes and exchange coefficients for heat at Dumont d'Urville, East Antarctica

1999 ◽  
Vol 11 (1) ◽  
pp. 93-99 ◽  
Author(s):  
S. Argentini ◽  
G. Mastrantonio ◽  
A. Viola
Keyword(s):  
Boundary Layer ◽  
Heat Fluxes ◽  
East Antarctica ◽  
Turbulent Heat ◽  
Convective Boundary ◽  
Doppler Sodar ◽  
Turbulent Heat Fluxes ◽  
Unstable Boundary Layer ◽  
Sodar Measurements ◽  
The Antarctic

Simultaneous acoustic Doppler sodar and tethersonde measurements were used to study some of the characteristics of the unstable boundary layer at Dumont d'Urville, Adélie Land, East Antarctica during the summer 1993–94. A description of the convective boundary layer and its behaviour in connection with the wind regime is given along with the frequency distribution of free convection episodes. The surface heat flux has been evaluated using the vertical velocity variance derived from sodar measurements. The turbulent exchange coefficients, estimated by coupling sodar and tethered balloon measurements, are in strong agreement with those present in literature for the Antarctic regions.

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