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 Calcareous nannofossil biostratigraphy of an outcrop section of Aptian sediments of west-central Portugal (Lusitanian Basin)

2009 ◽  
Vol 28 (2) ◽  
pp. 153-160 ◽  
Author(s):  
Rui O. B. P. Da Gama ◽  
Paul R. Bown ◽  
M. Cristina Cabral
Keyword(s):  
Carbon Isotope ◽  
Calcareous Nannofossil ◽  
Subsequent Increase ◽  
New Approach ◽  
Carbon Isotope Excursion ◽  
Central Portugal ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Isotope Stratigraphy ◽  
Early Late ◽  
Lusitanian Basin

Abstract. The present work is the first study of nannofossils from the Ponta Alta and Praia da Lagoa members of the Cresmina Formation and provides a new approach to establishing the age of these sediments. Nannofossil biostratigraphy improves previous age assignments: the Ponta Alta Member is placed within the latest Early Aptian, the passage between the Ponta Alta to the Praia da Lagoa members is assigned an early Late Aptian age and the Praia da Lagoa member is assigned an age not younger than the early Late Aptian. The lower half of the Rodísio Formation is assigned an age not younger than the Albian.The integration of the nannofossil results with isotope stratigraphy provides support for the age attributions and calibration with more open-marine sections. The low abundance of nannoconids observed within the Ponta Alta Member coincides with the OAE 1a carbon isotope excursion and is possibly a manifestation of the ‘nannoconid crisis’ event. The subsequent increase in the abundance of nannoconids in the upper Ponta Alta Member coincides with the highest values of the δ13C isotope anomaly and may reflect a position above the ‘nannoconid crisis’ event in the early Late Aptian.

A review of tropical calcareous nannofossil biostratigraphy across the early/late oligocene: a new taxon-range zone

2019 ◽  
Vol 52 (3) ◽  
pp. 321-340
Author(s):  
Mohammed H. Aljahdali ◽  
Sherwood W. Wise Jr. ◽  
David Bord ◽  
James Pospichal ◽  
Tugba Cevik
Keyword(s):  
New Taxon ◽  
Late Oligocene ◽  
Calcareous Nannofossil ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Early Late

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 PALEOBATHYMETRIC EVOLUTION OF THE EARLY LATE MIOCENE DEPOSITS OF THE PRE-APULIAN ZONE, LEVKAS ISLAND, IONIAN SEA

2018 ◽  
Vol 40 (1) ◽  
pp. 39 ◽  
Author(s):  
H. Drinia ◽  
A. Antonarakou ◽  
G. Kontakiotis ◽  
N. Tsaparas ◽  
M. Segou ◽  
...  
Keyword(s):  
Late Miocene ◽  
Foreland Basin ◽  
Tectonic Activity ◽  
Turbidity Currents ◽  
Ionian Sea ◽  
Foraminiferal Assemblage ◽  
External Domain ◽  
Benthic Foraminiferal Assemblage ◽  
Early Late

The Manassi section in Levkas Island belongs to the Pre-Apulian (Paxos) zone, the most external domain of the Hellenic realm. Its Early Tortonian sediments contain a rich foraminiferal fauna dominated, in numbers of individuals, by planktic species. Its benthic foraminiferal assemblage is characterized by a high number of taxa, with low numbers of individuals. Their study provides a basis for interpreting the paleobathymetry of the basin.The Manassi section represents deposition in upper to lower bathyal depths, during a period of intense tectonic activity. Downslope transport of fauna by turbidity currents partly overprints the signal of paleobathymetrically-diagnostic foraminifera distribution. The recognition of allochthonous taxa is used, together with %P, to identify turbidite beds intercalated with in-situ marly sediments. The micropaleontological and paleobathymetrical analyses of the studied sediments indicate that these correspond to distal atypical flysch deposited in the foredeep depozone of the most external domain (Pre-Apulian zone) of the Hellenide foreland basin.

Sign in / Sign up

Export Citation Format

Share Document