scholarly journals Carbonate Platform Development in an Intraoceanic Arc Setting: Costa Rica’s Largest Limestone Sequence - The Fila de Cal Formation (Middle Eocene to Lower Oligocene)

2018 ◽  
Vol 58 ◽  
Author(s):  
Angela Bolz ◽  
Claudio Calvo
Keyword(s):  
Carbonate Platform ◽  
Middle Eocene ◽  
Lower Oligocene ◽  
Platform Development ◽  
Arc Setting

Herpetofauna of the Calf Creek Local Fauna (Lower Oligocene: Cypress Hills Formation) of Saskatchewan

1972 ◽  
Vol 9 (12) ◽  
pp. 1612-1631 ◽  
Author(s):  
J. Alan Holman
Keyword(s):  
Middle Eocene ◽  
Tropical Climate ◽  
Local Fauna ◽  
Lower Oligocene ◽  
Bridger Formation

A Lower Oligocene deposit, the Calf Creek local fauna of the Cypress Hills Formation, near Eastend, Saskatchewan, yielded the remains of one salamander, three anurans, three turtles, a crocodilian, six lizards, and three snakes. All of the 13 herpetological families identified are extant. The four amphibian genera identified are extant, but only two of nine reptilian genera identified are living today. One genus and species and one species of iguanid lizard, one species of xantusiid lizard, and one species of small boid snake are described as new. The Calf Creek local fauna herpetofauna indicates a subtropical or tropical climate. The herpetofauna of the Calf Creek local fauna shows several differences from the herpetofauna of the Middle Eocene Tabernacle Butte local fauna of the Bridger Formation of Wyoming.

An Early Oligocene age for the oldest known monkeys and rodents of South America

2021 ◽  
Vol 118 (37) ◽  
pp. e2105956118
Author(s):  
Kenneth E. Campbell ◽  
Paul B. O’Sullivan ◽  
John G. Fleagle ◽  
Dorien de Vries ◽  
Erik R. Seiffert
Keyword(s):  
South America ◽  
Amazon Basin ◽  
Middle Eocene ◽  
Detrital Zircons ◽  
Age Difference ◽  
Early Oligocene ◽  
Lower Oligocene ◽  
Upper Oligocene ◽  
Caviomorph Rodents ◽  
Age Estimates

The Santa Rosa fossil locality in eastern Perú produced the first Paleogene vertebrate fauna from the Amazon Basin, including the oldest known monkeys from South America. This diverse paleofauna was originally assigned an Eocene age based largely on the stage of evolution of the site’s caviomorph rodents and marsupials. Here, we present detrital zircon dates that indicate that the maximum composite age of Santa Rosa is 29.6 ± 0.08 Ma (Lower Oligocene), although several zircons from Santa Rosa date to the Upper Oligocene. The first appearance datum for Caviomorpha in South America is purported to be the CTA-27 site in the Contamana region of Perú, which is hypothesized to be ∼41 Ma (Middle Eocene) in age. However, the presence of the same caviomorph species and/or genera at both CTA-27 and at Santa Rosa is now difficult to reconcile with a >11-My age difference. To further test the Middle Eocene age estimate for CTA-27, we ran multiple Bayesian tip-dating analyses of Caviomorpha, treating the ages of all Paleogene species from Perú as unknown. These analyses produced mean age estimates for Santa Rosa that closely approximate the maximum 29.6 ± 0.08 Ma composite date provided by detrital zircons, but predict that CTA-27 is much younger than currently thought (∼30 Ma). We conclude that the ∼41 Ma age proposed for CTA-27 is incorrect, and that there are currently no compelling Eocene records of either rodents or primates in the known fossil record of South America.

Geological Correlation Between Northern Cyprus And Southern Anatolia

2021 ◽  
Author(s):  
Yucel Yilmaz
Keyword(s):  
Carbonate Platform ◽  
Middle Eocene ◽  
Source Region ◽  
Oceanic Lithosphere ◽  
Late Eocene ◽  
Central Anatolia ◽  
Late Cenozoic ◽  
Ophiolitic Mélange ◽  
South Central ◽  
Northern Cyprus

The island of Cyprus constitutes a fragment of southern Anatolia separated from the mainland by left-oblique transtension in late Cenozoic time. However, a geological framework of offset features of the south-central Anatolia, for comparison of Cyprus with a source region within and west of the southeastern Anatolian suture zone, has not yet been developed. In this paper, I enumerate, describe, and compare a full suite of potentially correlative spatial and temporal elements exposed in both regions. Northern Cyprus and south-central Anatolia have identical tectonostratigraphic units. At the base of both belts, crop out ophiolitic mélange-accretionary complex generated during the northward subduction of the NeoTethyan Oceanic lithosphere from the Late Cretaceous until the end of middle Eocene. The nappes of the Taurus carbonate platform were thrust above this internally chaotic unit during late Eocene. They began to move as a coherent nappe pile from that time onward. An asymmetrical flysch basin was formed in front of this southward moving nappe pile during the early Miocene. The nappes were then thrust over the flysch basin fill and caused its tight folding. Cyprus separated from Anatolia in the Pleistocene-Holocene when, transtensional oblique faults with dip-slip components caused the development of the Adana and Iskenderun basins and the separation of Cyprus from Anatolia.

scholarly journals Aptian carbonate platform development in the Southern Iberian Palaeomargin (Prebetic of Alicante, SE Spain)

2019 ◽  
Vol 190 ◽  
pp. 3 ◽  
Author(s):  
Peter W. Skelton ◽  
José Manuel Castro ◽  
Pedro Alejandro Ruiz-Ortiz
Keyword(s):  
Carbonate Platform ◽  
Outer Shell ◽  
Data Link ◽  
Se Spain ◽  
Large Size ◽  
Seawater Ph ◽  
Present Study Area ◽  
Platform Development ◽  
Transitional Phase ◽  
Upper Slope

The Aptian stratigraphic record of the Alicante region consists of: a rudist and coral-rich carbonate platform of earliest Aptian age (Llopis Formation), with a discontinuous siliciclastic member at its top; followed by late Early, to Late Aptian hemipelagic marls and marlstones (Almadich Formation); and then by renewed carbonate platform development of Late Aptian to earliest Albian age (Seguilí Formation). In the Llopis Formation, SW-dipping, massive clinoform beds of bioclastic debris are succeeded by flat-lying platform-top beds. The latter show a cyclically regressive stacking of biofacies, with rudist-dominated floatstone in their lower parts passing upwards to finer-grained, more sparsely fossiliferous bed tops with burrow mottling. Caprinid rudists, with originally almost wholly aragonitic shells, dominate the external platform-top facies, while more internal facies contain a mix of monopleurid, polyconitid and requieniid rudists, all with relatively slightly thicker development of the calcitic outer shell layer, together with caprinids. Biostratigraphic and carbon-isotope data link the termination of the Llopis platform with the onset of OAE1a. The carbonate platform of the Seguilí Formation again contains tabular platform-top beds showing repeated cyclic regression, with dense rudist and/or chondrodont floatstones overlain by sparser floatstones with wackestone matrix and secondarily filled burrows. But caprinids are now absent, while requieniids and polyconitids, some of large size, as well as radiolitids, all with thickened calcitic outer shell layers, accompany the tubular monopleurid, Mathesia, together with a greater development of Chondrodonta biofacies. The same overall pattern of biotic turnover from the Early, to the Late Aptian is confirmed in other parts of Iberia and contiguous regions. Moreover, Iberian platforms of late Early Aptian age outside the present study area reveal a transitional phase with an increasing proportion of polyconitids in the outer platform-top to upper slope facies at the expense of caprinids. The siliciclastic influx at the top of the Llopis Formation implies a climatic shift from arid, to relatively more humid/pluvial conditions through the mid-Early Aptian, as seen in several other Iberian sections. This climatic change was probably forced by the intensified greenhouse conditions at the onset of OAE1a. By contrast with these Iberian platforms, caprinids continued to dominate the outer platform-top zones of some central to southern Tethyan platforms until the close of the Early Aptian. This broad palaeolatitudinal differentiation of rudist associations within the Tethyan belt implies a climatic influence, whether exerted through thermal modulation of seawater pH and/or aragonite saturation, variation in nutrient flux, or any combination of these.

Oligocene and Miocene Carbonate Platform Development In the Browse Basin, Australian Northwest Shelf

2017 ◽  
Vol 87 (8) ◽  
pp. 795-816 ◽  
Author(s):  
Johannes Belde ◽  
Stefan Back ◽  
Julien Bourget ◽  
Lars Reuning
Keyword(s):  
Carbonate Platform ◽  
Platform Development

Carbonate platform development in a Paleoproterozoic extensional basin, Vempalle Formation, Cuddapah Basin, India

2014 ◽  
Vol 91 ◽  
pp. 263-279 ◽  
Author(s):  
Gopal Chakrabarti ◽  
Debasish Shome ◽  
Subhasish Kumar ◽  
George M. Stephens ◽  
Linda C. Kah
Keyword(s):  
Carbonate Platform ◽  
Cuddapah Basin ◽  
Extensional Basin ◽  
Platform Development ◽  
Vempalle Formation

Large-scale carbonate platform development of Cay Sal Bank, Bahamas, and implications for associated reef geomorphology

Geomorphology ◽  
2014 ◽  
Vol 222 ◽  
pp. 25-38 ◽  
Author(s):  
Sam Purkis ◽  
Jeremy Kerr ◽  
Alexandra Dempsey ◽  
Andrew Calhoun ◽  
Liisa Metsamaa ◽  
...  
Keyword(s):  
Large Scale ◽  
Carbonate Platform ◽  
Platform Development ◽  
Reef Geomorphology
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