Eocene microplankton from La Meseta Formation, northern Seymour Island

1992 ◽  
Vol 4 (3) ◽  
pp. 355-362 ◽  
Author(s):  
Christopher D. Cocozza ◽  
Ciara M. Clarke
Keyword(s):  
Late Eocene ◽  
Early Eocene ◽  
Shallow Marine ◽  
Dinoflagellate Cyst ◽  
Two Samples ◽  
Low Diversity ◽  
La Meseta Formation ◽  
Marine System ◽  
Near Shore ◽  
Seymour Island

Twenty two samples collected from the Tertiary La Meseta Formation of Cape Wiman, Seymour Island, Antarctic Peninsula yielded abundant and moderately diverse assemblages of marine palynoflora, dominated by dinoflagellate cysts, together with acritarchs and chlorophyta. The assemblages can be divided into three association: Association 1, characterized by low diversity dinoflagellate assemblage of late Early Eocene age which are dominated by Enigmadinium cylindrifloriferum; Association 2 characterized by more diverse dinoflagellate cyst assemblages, which show a marked decrease in the dominance of E. cylindrifloriferum, and an increase in relative abundance of Areosphaeridium cf. diktyoplokus; and Association 3 which is characterized by a decrease in dinoflagellate cyst diversity up section. Changes in dinoflagellate cyst dominance and diversity throughout the section suggests a gradation from a stressed, shallow marine palaeoenvironment to a more open near-shore, shallow marine system becoming progressively more nearshore up section. The assemblages are no older than late Early Eocene in age, and possibly as young as Mid–Late Eocene.

The youngest record of fossil land mammals from Antarctica; its significance on the evolution of the terrestrial environment of the Antarctic Peninsula during the late Eocene

1997 ◽  
Vol 71 (2) ◽  
pp. 348-350 ◽  
Author(s):  
S. F. Vizcaino ◽  
M. Bond ◽  
M. A. Reguero ◽  
R. Pascual
Keyword(s):  
Antarctic Peninsula ◽  
Present Note ◽  
Late Eocene ◽  
South American ◽  
Terrestrial Environment ◽  
Shallow Marine ◽  
Early Oligocene ◽  
La Meseta Formation ◽  
The Antarctic ◽  
Seymour Island

The record of fossil land mammals from Antarctica has been restricted previously to the middle levels of the Eocene-?early Oligocene La Meseta Formation in Seymour Island, Antarctic Peninsula. This mostly shallow-marine sequence was divided informally into seven subunits (Tertiary Eocene La Meseta or TELM 1 to 7) by Sadler (1988). Land mammals, representing South American lineages of marsupials, edentates, and ungulates were recovered from TELM 3, 4, and 5 (Marenssi et al., 1994; Vizcaíno et al., 1994). The purpose of the present note is to report the discovery of a well-preserved ungulate tooth from the uppermost level of the La Meseta Formation (TELM 7) and to discuss its paleoenvironmental implications.

Foraminifera from the Eocene La Meseta Formation of Isla Marambio (Seymour Island), Antarctic Peninsula

2012 ◽  
Vol 24 (4) ◽  
pp. 408-416 ◽  
Author(s):  
Andrzej Gaździcki ◽  
Wojciech Majewski
Keyword(s):  
New Zealand ◽  
Early Eocene ◽  
West Antarctica ◽  
Shallow Marine ◽  
Lower Member ◽  
La Meseta Formation ◽  
Characteristic Species ◽  
First Time ◽  
Marine Nearshore ◽  
Seymour Island

AbstractBenthic foraminiferal assemblages are described for the first time from the early Eocene of West Antarctica. They come from the lower member (Telm1) of the La Meseta Formation of Isla Marambio (Seymour Island). Two distinctive assemblages, dominated by Nonionellina, Nonionella, Globocassidulina, and Eilohedra, as well as by Globocassidulina, Cribroelphidium, Guttulina, and Lobatula, indicate restricted, shallow marine, nearshore conditions. Their most characteristic species show distinct affinities with Eocene faunas of New Zealand and Patagonia, as well as with stratigraphically younger Antarctic foraminiferal communities.

scholarly journals Reticulate Nummulites (N. fabianii Linage) and Age of the Pellatispira-Beds of the Drazinda Formation, Sulaiman Range, Pakistan

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Ozcan E
Keyword(s):  
Mediterranean Region ◽  
Late Eocene ◽  
Test Surface ◽  
Time Interval ◽  
Late Oligocene ◽  
Shallow Marine ◽  
Western Tethys ◽  
Two Samples ◽  
Evolutionary Scheme ◽  
Weak Surface

The Eocene shallow marine Pellatispira-beds in the upper part of the Drazinda Formation represent the latest phase of Cenozoic Tethyan marine deposition in the Sulaiman Range, West Pakistan. The unit consists of stratigraphically important taxa as Heterostegina,Silvestriella, Pellatispira, a new Baculogypsina (possibly ancestral to modern Baculogypsina) and reticulate Nummulites implying a latest middle to late Eocene (late Bartonian-Priabonian) age. A more precise age of the unit requires the biometric study of reticulate Nummulites, the evolutionary scheme of which is better known from the peri-Mediterranean region in the Tethys. This group, which was subdivided into a series of successive chrono-species based on the biometry of inner cross-diameter of proloculus and changes in the types of granulation/reticulation on the test surface in the late Eocene-late Oligocene interval, appears to have a significant biostratigraphic potential for a high-resolution biostratigraphy in the peri-Mediterranean region (Western Tethys). The reticulate Nummulites in two samples from Rakhi Nala and Zinda Pir, ZP22 and RNB10, were studied and compared with those from the peri-Mediterranean region. The isolated specimens have a weak surface granulation externally, a distinct small umbonal granule (pile) and typical reticulation. The samples ZP22 and RNB10 from Zinda Pir and and Rakhi Nala sections have an average inner cross diameter of proloculus of 152.0 and 153.0 μm respectively. The reticulate Nummulites in both samples are assigned to N. hormoensis, a chrono-species characteristic for the shallow benthic zone (SBZ 18), referable to latest Bartonian-early Priabonian time interval. Since Heterostegina in peri-Mediterranean region and in Pakistan belongs to different lineages, a correlation of N. hormoensis in the studied samples with the wellestablished evolutionary scheme of Heterostegina reticulata and H.armenica lineages from the Western Tethys was not possible.

Manumiella seymourensis new species, a stratigraphically significant dinoflagellate cyst from the Maastrichtian of Seymour Island, Antarctica

1999 ◽  
Vol 73 (3) ◽  
pp. 373-379 ◽  
Author(s):  
Rosemary A. Askin
Keyword(s):  
New Species ◽  
Shallow Marine ◽  
Dinoflagellate Cyst ◽  
Morphological Variations ◽  
Palynological Assemblages ◽  
Lower Maastrichtian ◽  
Superficial Similarity ◽  
Almost All ◽  
Shallow Marine Sediments ◽  
Seymour Island

The peridiniacean dinoflagellate cyst Manumiella seymourensis new species described herein characterizes Maastrichtian shallow marine sediments cropping out on Seymour Island, northeastern Antarctic Peninsula. It dominates palynological assemblages throughout the lower Maastrichtian (and possibly uppermost Campanian) to lower upper Maastrichtian part of the López de Bertodano Formation. Despite its superficial similarity to some other southern mid to high paleolatitude Campanian-Maastrichtian species, M. seymourensis represents a discrete, biostratigraphically useful population of peridiniacean cysts. Its morphology and size parameters remain consistent throughout almost all of its stratigraphic range, equated with relatively stable environmental conditions throughout much of the Maastrichtian in the James Ross Basin. Morphological variations, equated with environmental change, are apparent in specimens in the lowermost and uppermost parts of its range.

An Eocene wrasse (Perciformes; Labridae) from Seymour Island

1992 ◽  
Vol 4 (2) ◽  
pp. 235-237 ◽  
Author(s):  
Douglas J. Long
Keyword(s):  
Climatic Change ◽  
Trophic Structure ◽  
Late Eocene ◽  
Pharyngeal Tooth ◽  
Tooth Plate ◽  
Antarctic Waters ◽  
La Meseta Formation ◽  
First Occurrence ◽  
Wide Scale ◽  
Seymour Island

A nearly complete lower pharyngeal tooth-plate from a large (over 60 cm long) fossil wrasse (Perciformes: Labridae) was recently recovered from the middle to late Eocene La Meseta Formation on Seymour Island, Antarctic Peninsula. This find increases the number of teleosts from the Eocene of Antarctica to five taxa, and further illustrates the diversity of the ichthyofauna in the Eocene Weddellian Sea prior to wide-scale climatic change in the Southern Ocean. The fossil wrasse represents the first occurrence of this family in Antarctica, and is one of the oldest fossils of this family from the Southern Hemisphere. Wrasses are not found in Antarctic waters today, and probably became extinct during the Oligocene due to a combination of climatic change, loss of shallow-water habitat, and changes in the trophic structure of the Wedell Sea.

The incidence of unusual test morphologies of Eocene Larger benthic foraminifera: An example of Paleogene Adriatic Carbonate Platform

2021 ◽  
Author(s):  
Vlasta Ćosović ◽  
Jelena Španiček ◽  
Katica Drobne ◽  
Ervin Mrinjek
Keyword(s):  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Middle Eocene ◽  
Morphological Diversity ◽  
Late Eocene ◽  
Early Eocene ◽  
Coralline Red Algae ◽  
Larger Benthic Foraminifera ◽  
Shallow Marine ◽  
Scientific Project

<p>The Paleogene Adriatic carbonate platform(s) existed within the Central NeoTethys (around 32 N paleolatitude) from the Danian to the late Eocene (Bartonian/Priabonian) and produced a succession of limestones up to 500 m thick, rich in larger benthic foraminifera (LBF). The Eocene sediments are widely distributed along the eastern Adriatic coast and have been studied for many years. Taking into account the climatic changes that took place within the Eocene (Early Eocene and Middle Eocene climatic optima, known as EECO, MECO), special attention was paid to the composition of shallow-marine foraminiferal assemblages. The studies reveal the following trends: (1) the alveolinid-dominated assemblages were replaced by nummulitid-dominated assemblages around the MECO; (2) the greater species and morphological diversity (spherical, ellipsoid, extremely elongated fusiform) of the alveolinid fauna was evident at the EECO; (3) the nummulitid-dominated fauna was characterized by less diversified assemblages compared to the alveolinid ones and by the co-occurrence of scleractinian corals, coralline red algae and aborescent foraminifera. The occurrence of twin embryos has been assigned to the early Eocene in the alveolinid populations, especially in Alveolina levantina and A. axiampla (in some sections, the frequency is greater than 5%), and these coalesced embryos have the same size as the single form (usually they are smaller). The LBF assemblages of Middle Eocene showed a greater frequency of doubled adult tests (Orbitolites sp., Nummulites sp.). The origin of these unusual morphologies is poorly known, usually described as the results of stressful conditions. Considering the timing of the appearance of such morphologies, temperature and associated changes in the shallow-marine environment could be the cause.</p><p>This study is carried out as part of the scientific project IP-2019-04-5775 BREEMECO, funded by Croatian Scientific Foundation.</p>

scholarly journals The earliest fossil record of a medium-sized penguin

2011 ◽  
Vol 32 (3) ◽  
pp. 269-277 ◽  
Author(s):  
Piotr Jadwiszczak ◽  
Sandra Chapman
Keyword(s):  
Antarctic Peninsula ◽  
Early Phase ◽  
Fossil Record ◽  
Taxonomic Diversity ◽  
Distal Humerus ◽  
Early Eocene ◽  
British Antarctic Survey ◽  
Early Eocene Climatic Optimum ◽  
La Meseta Formation ◽  
Seymour Island

The earliest fossil record of a medium-sized penguinThe fossil record of Antarctic Sphenisciformes dates as early as the late Palaeocene Cross Valley Formation, Seymour Island, Antarctic Peninsula. However, the best known Antarctic locality for early penguin remains (mainly isolated bones) is the Eocene La Meseta Formation that outcrops in the northeast of Seymour Island. The analysis of an unstudied set of specimens collected there by members of the British Antarctic Survey in 1989 has resulted in identification of a distal humerus from the unit Telm3 (early Eocene) of the formation that is the oldest known bone attributable to a medium-sized (in the context of the entire Cainozoic era) penguin. This find suggests that the origin of these birds, in conjunction with an increase in taxonomic diversity of the Eocene Sphenisciformes, was related to the Early Eocene Climatic Optimum (EECO) or, more probably, the early phase of subsequent cooling.

scholarly journals First articulated skeleton of Palaeeudyptes gunnari from the late Eocene of Isla Marambio (Seymour Island), Antarctica

2010 ◽  
Vol 22 (3) ◽  
pp. 289-298 ◽  
Author(s):  
Carolina Acosta Hospitaleche ◽  
Marcelo Reguero
Keyword(s):  
Late Eocene ◽  
La Meseta Formation ◽  
Systematic Determination ◽  
Specific Assignment ◽  
Seymour Island

AbstractThe first articulated skeleton of a penguin from the late Eocene of Antarctica is described. MLP 96-I-6-13 comes from the upper Submeseta Allomember (La Meseta Formation) of Isla Marambio (locality DPV 10/84). The significance of this finding in the context of the Anthropornis nordenskjoeldi biozone is discussed. An osteologic description of the recovered elements and a brief discussion of its systematic determination are provided. MLP 96-I-6-13 is the first articulated skeleton with sure specific assignment to Palaeeudyptes gunnari (Wiman, 1905), a species previously known only through isolated tarsometatarsi and included in the groups of Wiman.

Record of Late Miocene glacial deposits on Isla Marambio (Seymour Island), Antarctic Peninsula

2009 ◽  
Vol 22 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Sergio A. Marenssi ◽  
Silvio Casadío ◽  
Sergio N. Santillana
Keyword(s):  
Antarctic Peninsula ◽  
Late Miocene ◽  
Late Eocene ◽  
Weddell Sea ◽  
Volcanic Group ◽  
Lower Oligocene ◽  
La Meseta Formation ◽  
James Ross Island ◽  
Stratigraphic Sequences ◽  
Seymour Island

AbstractWe report and describe two new small diamictite outcrops on Isla Marambio (Seymour Island), Antarctic Peninsula. These rocks rest on an erosional unconformity on top of the Eocene La Meseta Formation and are unconformably covered by glaciomarine rocks of the ?Pliocene–Pleistocene Weddell Sea Formation. The lithology, fossil content and isotopic ages obtained strongly suggest that the rocks belong to the Hobbs Glacier Formation and support a Late Miocene age for this unit. Additionally, the dated basalt clast provides the oldest age (12.4 Ma) for the James Ross Island Volcanic Group recorded up to now. The here described diamictite cannot be confidently correlated with a glaciomarine unit previously assigned to the Late Eocene–Lower Oligocene taken as proof that initial expansion of ice on Antarctica encompassed the entire continent synchronously in the earliest Oligocene. However, it is now evident that there are likely to be more, short but important, stratigraphic sequences of key regional and Antarctic wide interest preserved on the plateau of Isla Marambio.

A new Eocene crab (Crustacea, Decapoda) from Seymour Island, Antarctica

1995 ◽  
Vol 7 (3) ◽  
pp. 277-281 ◽  
Author(s):  
María B. Aguirre-Urreta ◽  
Sergio Marenssi ◽  
Sergio Santillana
Keyword(s):  
New Zealand ◽  
High Latitude ◽  
Late Eocene ◽  
Early Tertiary ◽  
La Meseta Formation ◽  
Seymour Island

A new xanthid crab, Tumidocarcinus foersteri n. sp. is described from the La Meseta Formation on Seymour Island, Antarctica. The fossils were obtained from the Allomember Submeseta of Late Eocene age. As other representatives of the genus Tumidocarcinus were only known from New Zealand and Australia, this finding provides new insights on the palaeobiogeography of high latitude faunas during the Early Tertiary.

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