scholarly journals New data on the stratigraphic distribution of the nannofossil genus <i>Catinaster</i> and on evolutionary relationships among its species

2013 ◽  
Vol 32 (2) ◽  
pp. 197-205 ◽  
Author(s):  
Marina Ciummelli ◽  
Isabella Raffi
Keyword(s):  
Late Miocene ◽  
Short Interval ◽  
Evolutionary Relationships ◽  
Calcareous Nannofossil ◽  
Equatorial Atlantic ◽  
Eastern Equatorial Pacific ◽  
C 50 ◽  
Evolutionary Emergence ◽  
Early Late ◽  
The Tropical Pacific

Abstract. Examination of Upper Miocene–Lower Pliocene sediments at IODP Site U1338, in the Eastern Equatorial Pacific, provided new data on the distribution range of the calcareous nannofossil genus Catinaster. In addition to the the well-known occurrence of Catinaster coalitus and Catinaster calyculus in the early Late Miocene, we document Catinaster mexicanus in both the mid-late Miocene and the Early Pliocene. We confirm its taxonomic validity, rejecting previous interpretations of Pliocene C. mexicanus specimens as the result of dissolution of Discoaster altus. Instead, the Pliocene appearance of C. mexicanus seems to originate from the D. altus lineage. The short interval of occurrence (c. 50 ka) in the Late Miocene may document a preliminary evolutionary emergence of C. mexicanus that lacks any relationship with the other Catinaster species. Clear ancestor species to validate its independent origin from Discoaster are, however, missing. In the stratigraphic intervals where Catinaster species are found, their co-occurrence with Discoaster species bearing a prominent star-shaped boss on one side is noteworthy. This suggests that Catinaster and Discoaster at times developed a common morphological feature (a stellate structure, with or without hexaradiate symmetry), possibly under recurrent changes in climatic/environmental conditions. The data presented on C. mexicanus suggest a wider geographical distribution than previously thought, extending from the tropical Pacific to the Gulf of Mexico, equatorial Atlantic and tropical Indian oceans.

scholarly journals Late Miocene calcareous nannofossil genus <i>Catinaster:</i> taxonomy, evolution and magnetobiochronology

1998 ◽  
Vol 17 (1) ◽  
pp. 71-85 ◽  
Author(s):  
Alyssa Peleo-Alampay ◽  
David Bukry ◽  
Li Liu ◽  
Jeremy R. Young
Keyword(s):  
Indian Ocean ◽  
Gulf Of Mexico ◽  
Systematic Study ◽  
Late Miocene ◽  
Equatorial Pacific ◽  
Calcareous Nannofossil ◽  
New Subspecies ◽  
Eastern Equatorial Pacific ◽  
First Occurrence ◽  
The Indian Ocean

Abstract. A systematic study on the evolution and stratigraphic distribution of the species of Catinaster from several DSDP/ODP sites with magnetostratigraphic records is presented. The evolution of Catinaster from Discoaster is established by documentation of a transitional nannofossil species, Discoaster transitus. Two new subspecies, Catinaster coalitus extensus and Catinaster calyculus rectus are defined which appear to be intermediates in the evolution of Catinaster coalitus coalitus to Catinaster calyculus calyculus. The first occurrence of C. coalitus is shown to be in the lower part of C5n.2n at 10.7–10.9 Ma in the low to mid–latitude Atlantic and Pacific Oceans. The last occurrence of C. coalitus coalitus varies from the upper part of C5n.2n to the lower portion of C4A. Magnetobiostratigraphic evidence suggests that the FO of C. calyculus rectus is diachronous. Catinaster mexicanus occurs in the late Miocene and has been found only in the eastern equatorial Pacific, the Indian Ocean and the Gulf of Mexico.

scholarly journals Timing of Contractional Tectonics in the Miocene Foreland Basin System of the Umbria Pre-Apennines (Italy): An Updated Overview

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 97
Author(s):  
Francesco Brozzetti ◽  
Daniele Cirillo ◽  
Lucina Luchetti
Keyword(s):  
Late Miocene ◽  
Structural Unit ◽  
Multidisciplinary Approach ◽  
Foreland Basin ◽  
Calcareous Nannofossil ◽  
Large Dataset ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Early Late ◽  
Basin System ◽  
Over Time

A large dataset of lithostratigraphic and biostratigraphic data, concerning the Early-Late Miocene turbidite succession of the Umbria pre-Apennines, is presented and analyzed. The data come from the study of 24 sections that are representative of all the main tectonic units cropping out between the front of the Tuscan allochthon and the Umbria-Marche calcareous chain. The sections have been dated using quantitative calcareous nannofossil biostratigraphy and, wherever possible, they were correlated through key-beds recognition. Such a multidisciplinary approach allowed us to reconstruct the evolution of the Umbria foredeep over time and to unveil the chronology of compressive deformations by defining: (i) the onset of the foredeep stage in each structural unit, (ii) the age of depocenter-shifting from a unit to the adjacent one, (iii) the progressive deactivation of the western sector of the foredeep due to the emplacement of allochthon units, and (iv) the internal subdivisions of the basin due to the presence of foreland ramp faults or thrust-related structures. A further original outcome of our study is having brought to light the Late Burdigalian “out-of-sequence” reactivation of the Tuscan allochthon which bounded westward the foredeep, and the subsequent protracted period of tectonic stasis that preceded the deformations of the Umbrian parautochthon.

scholarly journals Paleoenvironmental conditions for the development of calcareous nannofossil acme during the late Miocene in the eastern equatorial Pacific

2014 ◽  
Vol 29 (3) ◽  
pp. 210-222 ◽  
Author(s):  
Catherine Beltran ◽  
Gabrielle Rousselle ◽  
Jan Backman ◽  
Bridget S. Wade ◽  
Marie Alexandrine Sicre
Keyword(s):  
Late Miocene ◽  
Equatorial Pacific ◽  
Calcareous Nannofossil ◽  
Eastern Equatorial Pacific

New early late Miocene species of Vishnuonyx (Carnivora, Lutrinae) from the hominid locality of Hammerschmiede, Bavaria, Germany

2021 ◽  
Author(s):  
Nikolaos Kargopoulos ◽  
Alberto Valenciano ◽  
Panagiotis Kampouridis ◽  
Thomas Lechner ◽  
Madelaine Böhme
Keyword(s):  
Late Miocene ◽  
Early Late

Neogastropod molluscs from the Miocene of western Amazonia, with comments on marine to freshwater transitions in molluscs

2002 ◽  
Vol 76 (2) ◽  
pp. 265-270 ◽  
Author(s):  
Geerat J. Vermeij ◽  
Frank P. Wesselingh
Keyword(s):  
New Species ◽  
Water Level ◽  
Late Miocene ◽  
Southeast Asian ◽  
South American ◽  
Seasonal Fluctuations ◽  
Early Late ◽  
A New Species ◽  
Freshwater Environments

Two neogastropod species occur in brackish intervals in the Pebas Formation (late Middle to early Late Miocene) of Peru and Colombia in western Amazonia. Purpura woodwardi Roxo, 1924, is assigned to Melongena Schumacher, 1817 (Melongenidae), and ?Nassarius reductus (Nassariidae) is recognized as a new species. These gastropods are among the very few marine invaders in the otherwise freshwater Pebas fauna. The small number of marine to freshwater transitions among South American molluscs contrasts with the situation among South American fishes and southeast Asian molluscs. It may be related to seasonal fluctuations in water level and anoxia in present-day South American freshwater environments, as well as to predation and productivity.

scholarly journals Skillful prediction of tropical Pacific fisheries provided by Atlantic Niños

2021 ◽  
Author(s):  
Iñigo Gómara ◽  
Belén Rodríguez-Fonseca ◽  
Elsa Mohino ◽  
Teresa Losada ◽  
Irene Polo ◽  
...  
Keyword(s):  
Large Scale ◽  
Southern Oscillation ◽  
Marine Ecosystem ◽  
Ecosystem Model ◽  
Tropical Pacific ◽  
Equatorial Atlantic ◽  
Climate Conditions ◽  
Marine Food Web ◽  
Marine Ecosystem Model ◽  
The Tropical Pacific

AbstractTropical Pacific upwelling-dependent ecosystems are the most productive and variable worldwide, mainly due to the influence of El Niño Southern Oscillation (ENSO). ENSO can be forecasted seasons ahead thanks to assorted climate precursors (local-Pacific processes, pantropical interactions). However, owing to observational data scarcity and bias-related issues in earth system models, little is known about the importance of these precursors for marine ecosystem prediction. With recently released reanalysis-nudged global marine ecosystem simulations, these constraints can be sidestepped, allowing full examination of tropical Pacific ecosystem predictability. By complementing historical fishing records with marine ecosystem model data, we show herein that equatorial Atlantic Sea Surface Temperatures (SSTs) constitute a superlative predictability source for tropical Pacific marine yields, which can be forecasted over large-scale areas up to 2 years in advance. A detailed physical-biological mechanism is proposed whereby Atlantic SSTs modulate upwelling of nutrient-rich waters in the tropical Pacific, leading to a bottom-up propagation of the climate-related signal across the marine food web. Our results represent historical and near-future climate conditions and provide a useful springboard for implementing a marine ecosystem prediction system in the tropical Pacific.

Complex networks approach for detecting tropical basin interactions

2021 ◽  
Author(s):  
Belen Rodríguez de Fonseca ◽  
Veronica Martín-Gómez ◽  
Jose María Aliganga
Keyword(s):  
Indian Ocean ◽  
Decadal Variability ◽  
Tropical Indian Ocean ◽  
Tropical Pacific ◽  
Equatorial Atlantic ◽  
Tropical Oceans ◽  
Collective Interaction ◽  
Tropical North Atlantic ◽  
Key Factor ◽  
The Tropical Pacific

&lt;p&gt;Interaction between the tropical Pacific, Atlantic, and Indian Ocean basins is increasingly recognized as a key factor in understanding climate variability on interannual to decadal timescales. Most of the studies deal with the connection between pair of basins and less attention has been paid to analyze the degree of collective interaction among the three tropical oceans and its variability along time.In this study, we consider a complex network perspective to analyze the collective connectivity among the three tropical basins. To do so, we first construct a climate network considering as network&amp;#8217; nodes the indices that represent the variability of the SST over the tropical Pacific, the tropical north Atlantic, the equatorial Atlantic and the tropical Indian Ocean. Then, we focus on detecting periods of maximum degree of collective connectivity (synchronization periods) using the mean network distance definition.Results show that the degree of collective connectivity among the three tropical oceans present a large muti-decadal variability and that during the observed period there were two synchronization periods: one developed over the period (1900-1935) and the other from 1975 to present. A period center in the 1950&amp;#8217;s is characterized by being the three basins uncoupled .Using this information, an analysis of background conditions in the ocean and the atmosphere has been conducted in order to elucidate causes for this change in connectivity.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document