High-resolution calcareous nannofossil biostratigraphy from the Bathonian ASSP of the Cabo Mondego Section (Lusitanian Basin, Portugal)

2018 ◽  
Author(s):  
Gatsby-Emperatriz López-Otálvaro ◽  
Maria Helena Henriques
Keyword(s):  
High Resolution ◽  
Calcareous Nannofossil ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Lusitanian Basin

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.

scholarly journals Early-Middle Miocene from Kotaphi hill section (Nicosia, Cyprus): preliminary biostratigraphy and paleoceanographic implications

2016 ◽  
Vol 47 (1) ◽  
pp. 62
Author(s):  
M. Athanasiou ◽  
M. Triantaphyllou ◽  
M. Dimiza ◽  
A. Gogou ◽  
I. Bouloubassi ◽  
...  
Keyword(s):  
High Resolution ◽  
Key Words ◽  
Middle Miocene ◽  
High Abundance ◽  
Common Occurrence ◽  
Calcareous Nannofossil ◽  
Preliminary Results ◽  
Marine Deposits ◽  
Total Absence ◽  
Calcareous Nannofossil Biostratigraphy

Calcareous nannofossil biostratigraphy from Kotaphi Hill section allowed not only the biostratigraphic zonation of the Miocene units but also provided evidence for a distinct warm phase known as the Middle Miocene Climate Optimum (MMCO). Kotaphi Hill section is located in Agrokipia village (Nicosia region, Cyprus) and consists of cyclic marine deposits of the Pakhna Formation. High resolution sampling has been conducted and 84 samples were collected. Preliminary results indicated that several important calcareous nannofossil events can be consistently recognized along the studied section. High abundances of Discoaster druggii and Highest occurrence (HO) of Sphenolithus procerus suggest the presence of NN2 biozone while, LO of Sphenolithus belemnos has been used to recognize the base of biozone NN3. Upwards, Lowest Common Occurrence (LCO) of Sphenolithus heteromorphus marked the NN3-4 boundary-level. Biozone NN4 in Kotaphi Hill section is featured by high abundance of S. heteromorphus whereas total absence of the species together with the LO of Helicosphaera walbedorfensis mark the Paracme Beginning (PB) of S. heteromorphus interval. High abundance of warm indicators such as Discoasterids, S. heteromorphus, S. moriformis and Helicosphaera carteri observed in our material may partly reflect the warm phase of MMCO. Key words: Agrokipia village, Pakhna Formation, Cyprus, Sphenolithus heteromorphus, Middle Miocene Climate Optimum.

Earliest Miocene calcareous nannofossil biostratigraphy from the low-latitude Pisco Basin (Peru)

Stratigraphy ◽  
2019 ◽  
Vol 16 (2) ◽  
pp. 87-105
Author(s):  
Emilia R. Belia ◽  
Kevin E. Nick ◽  
Erika Bedoya Agudelo ◽  
David K. Watkins
Keyword(s):  
Calcareous Nannofossil ◽  
Low Latitude ◽  
Calcareous Nannofossil Biostratigraphy
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