scholarly journals Eocene to Oligocene nannofossils stratigraphy and environmental conditions in Izeh Province, Zagros Basin, East Tethys

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Saeedeh Senemari ◽  
Farah Jalili
Keyword(s):  
Environmental Changes ◽  
Late Eocene ◽  
Marine Phytoplankton ◽  
Asmari Formation ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Southwestern Iran ◽  
Pabdeh Formation ◽  
First Time ◽  
Palaeoenvironmental Conditions

AbstractData obtained from the calcareous nannofossils, distributed in the upper part of the Pabdeh Formation (Priabonian–Rupelian) and the lower part of the Asmari Formation (Chattian) in the Bid-Zard section, were used to investigate the Eocene to Oligocene palaeoenvironmental conditions in the southwest of Izeh, southwestern Iran (eastern Tethys). The upper part of the Pabdeh Formation was composed of shale, thin-bedded pelagic limestone and dolostone, which is disconformably overlain by the Asmari Formation. For the first time, 29 species of calcareous nannofossils belonging to 13 genera were identified in the studied section. The calcareous nannofossils in the upper part of the Pabdeh Formation indicate the Isthmolithus recurvus Zone/Sphenolithus pseudoradians Zone (combined zone), Ericsonia subdisticha Zone, Helicosphaera reticulata Zone and Sphenolithus praedistentus Zone, from the Priabonian to the Rupelian. The Sphenolithus ciperoensis Zone of the Chattian was identified in the lower part of the Asmari Formation. Calcareous nannofossil stratigraphy across the upper Eocene–Oligocene interval also reveals a disconformity at the Rupelian/Chattian transition due to a bio-event. Shallowing of the basin and environmental changes in this part of the Tethyan domain could have led to the lithostratigraphic and biostratigraphic changes. In fact, during the late Eocene to late Oligocene, marine phytoplankton was sensitive to climate changes such as decreasing temperature, as well as possibly to a nutrient increase and changes in basin depth.

The response of calcareous nannoplankton to the latest Pliensbachian-early Toarcian environmental changes in the Camino section (Basque Cantabrian Basin, North Spain)

2021 ◽  
pp. SP514-2020-256
Author(s):  
Ángela Fraguas ◽  
Juan José Gómez ◽  
Antonio Goy ◽  
María José Comas-Rengifo
Keyword(s):  
Environmental Changes ◽  
Principal Component ◽  
Black Shales ◽  
Time Interval ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Content Type ◽  
Lowermost Part ◽  
Supplementary Material ◽  
Basque Cantabrian Basin

AbstractQuantitative analysis performed on latest Pliensbachian-early Toarcian calcareous nannofossil assemblages from the Camino section (Basque Cantabrian Basin), allowed to decipher their response to the environmental changes recorded during this time interval, characterized by an extinction event. The results were introduced within a principal component analysis and compared to the stable isotope and total organic carbon curves. During the latest Pliensbachian, the Mirabile and the lowermost part of the Semicelatum Ammonite Subzones, Schizosphaerella, Bussonius prinsii, Biscutum finchii, Calcivascularis jansae and Similiscutum avitum, taxa that probably thrived in rather cold waters, dominated the calcareous nannofossil assemblages. Coinciding with the warmer and probably wetter conditions, which probably led to an increase in surface water fertility, recorded slightly below the extinction boundary, the mesotrophic taxa B. novum, L. hauffii and Calyculus spp. were dominant. Nevertheless, T. patulus and C. jansae, which became extinct just below the extinction boundary, show preferences for oligotrophic conditions. Salinities similar to those of modern oceans have been inferred around the extinction boundary, considering the coupling between the abundances of Calyculus spp. and the species richness, and the absence of black-shales. After the extinction boundary, nannofossil assemblages were dominated by the deep-dweller C. crassus and the shallow-dweller Lotharingius species, interpreted as opportunistic taxa. This work confirms that calcareous nannofossils are a useful tool for palaeoceanographic and palaeoenvironmental reconstructions, especially in terms of climatic changes.Supplementary material at https://doi.org/10.6084/m9.figshare.c.5481527

scholarly journals CALCAREOUS NANNOFOSSILS BIOSTRATIGRAPHY OF JADDALA FORMATION IN WELL (AJEEL-10), CENTRAL IRAQ

2021 ◽  
Vol 16 (3) ◽  
pp. 341-358
Author(s):  
Israa Sabah Al-Nuaimi ◽  
Omar Ahmed Al-Badrani
Keyword(s):  
Systematic Study ◽  
Late Eocene ◽  
Calcareous Nannofossils ◽  
The Future ◽  
First Time

A detailed systematic study of calcareous nannofossils was carried out for the Jaddala Formation in (Aj-10) well, Central Iraq. Seventy one species belong to twenty four genera of calcareous nannofossils were identified including sixty two of them were previously named and nine species were identified for the first time and they would not be given names until more information is obtained in the future to support this identification. It is a recorded of five biostratigraphic zone, which suggested the age of the Jaddala Formation to be of early to late Eocene. The recorded biozone includes the following: Reticulofenestra dictyoda (Deflandre in Deflandre & Fert, 1954) Stradner & Edwards, 1968 Partial Range Biozone (CNE 5); Discoaster sublodoensis Bramlette and Sullivan, 1961 Interval biozone (CNE 6-7); Nannotetrina cristata (Martini, 1958) Perch-Nielsen, 1971 Interval biozone (CNE 8); Nannotetrina alata (Martini in Martini & Stradner, 1960) Haq and Lohmann, 1976 Interval biozone (CNE 9); Chiasmolithus gigas Bramlette & Sullivan, 1961Range Biozone (CNE 10-11).

scholarly journals Calcareous nannofossil assemblages from Paleocene sediments of the Ukrainian Carpathians

2020 ◽  
Keyword(s):  
Time Scale ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Geological Time ◽  
Problem Statement ◽  
Geological Time Scale ◽  
Carpathian Region ◽  
Integrated Research ◽  
Lithostratigraphic Units ◽  
First Time

Problem statement. Detail study of both vertical and spatial distribution of calcareous nannofossils from the Paleocene sediments of the Ukrainian Carpathians enabled to determine the evolutional development of Haptophyta algae during the Paleocene, and became the basis for correlation of boundary markers and correlative biohorizons. Here we summarize data obtained from previous research, and also our own, and propose an updad biozonation of Paleocene sediments of the Northern and Southern slopes of the Ukrainian Carpathians. Prerious work. Calcareous nannofossil research of the area goes back to the 1960’s. These studies had a fragmentary character with only few sections examined for their nannofossil content. Materials and research methods. The paper includes the results of nannofossil research from numerous sections of Paleocene Flysch developed in the Outer and Inner Carpathian nappes. Discussion of the research data. The paper discusses the biozonation and correlation of local lithostratigraphic units of the Ukrainian Carpathians based on the detail study of nannofossils. For the first time, the complete successions of nannozones of the latest Geological Time Scale have been identified in the Ukrainian Carpathians. In the Outer (Flysch) Carpathians several nannozones were determined within the Skyba and Boryslav-Pokuttya nappes. There include – Markalius inversus / Biantholithus sparsus (NP1), Cruciplacolithus tenuis (NP2), Chiasmolithus danicus (NP3) and Ellipsolithus macellus (lower NP4) in the Upper Striy subsuite; top Ellipsolithus macellus (NP4), Fasciculithus tympaniformis (NP5), Heliolithus kleinpelliі (NP6) in Yaremcha Formation, Discoaster mohleri (NP7) in Bytkiv layers, Heliolithus riedelii (NP8), Discoaster multiradiatus (bottom NP9) from the Yamna suite; Chiasmolithus danicus (NP3) from Upper Bereznyan subsuite of Dukla nappe; Fasciculithus tympaniformis (NP5) in Gnylets suite of Chornohora nappe and Markalius inversus (NP1) in Urdyn suite of Svydovets nappe. Within the Inner Carpathians nannozones were defined in the Lower Metova subsuite of the Vezhany nappe – Biantholithus sparsus (NP1), Fasciculithus tympaniformis (NP5), Heliolithus kleinpelliі (NP6), Heliolithus riedelii (NP8); Sushmanets suite of Monastyrets nappe contained Fasciculithus tympaniformis (NP5), Heliolithus kleinpelliі (NP6) and Tribrachiatus contortus (NP10) of the Early Ypresian. The stratigraphic positioning of nannofossil assemblages was rectified and their correlation with foraminifera and dinocyst zones was demonstrated. These nannozone assemblages from the Ukrainian Carpathians are correlated with the Danian, Selandian and Thanetian stages of the Geological Time Scale (GTS, 2012 and 2016). This integrated research enables to rectify and modify the stratigraphic scheme of the Paleogene from the Carpathian region. Conclusions. A modern calcareous nannofossil biozonation of the latest International schemes has been recognized from the studied Paleocene sections of the Ukrainian Carpathians. Nine (9) nannozones ranging from NP1 (Early Danian) to NP9 (Late Thanetian – Early Ypresian) and also the lowest NP10 nannozone of Early Ypresian have been identified in strata from different structural-tectonic units. The nannofossil biozonation is correlated with those foraminifera and dinocyst biochronology. The age and correlation for the Paleocene stratigraphic subdivisions has been justified based on the nannofossil biostratigraphy. This resulted in the upgrading of the existing stratigraphic scheme of the Paleogene of the Ukrainian Carpathians.

scholarly journals High resolution integrated microbiostratigraphy of the Lower Jurassic (late Pliensbachian–early Toarcian) of central Italy

1998 ◽  
Vol 17 (2) ◽  
pp. 153-172 ◽  
Author(s):  
Raffaella Bucefalo Palliani ◽  
Emanuela Mattioli
Keyword(s):  
High Resolution ◽  
Evolutionary History ◽  
Central Italy ◽  
Lower Jurassic ◽  
High Potential ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Dinoflagellate Cyst ◽  
History Of ◽  
Global Events

Abstract. The integrated use of calcareous nannofossil and dinoflagellate cyst events in a study of the late Pliensbachian–early Toarcian interval in central Italy has yielded a high resolution biostratigraphy. The use of both the first and last occurrences of selected taxa belonging to the two phytoplankton groups allows the dating of the sediments with a very refined detail, even when lithologies are unfavourable to the preservation of one fossil group. The evolutionary history of calcareous nannofossils and dinoflagellate cysts during the early Jurassic and its links with global events are responsible for the high potential of this integrated biostratigraphy.

scholarly journals New Genus and Species of Gall Midges (Diptera, Cecidomyiidae, Porricondylinae, Holoneurini) from the Late Eocene Amber of Olevsk (Zhitomir Region, Ukraine)

2017 ◽  
Vol 51 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Z. A. Fedotova ◽  
E. E. Perkovsky
Keyword(s):  
New Species ◽  
New Genus ◽  
Late Eocene ◽  
Rovno Amber ◽  
New Genus And Species ◽  
Gall Midges ◽  
Two New Species ◽  
First Time ◽  
Eocene Amber

Abstract Gall midges are reported for the first time in Late Eocene Rovno amber from the Olevsk, Zhitomir Region. This is the second amber locality to yield gall midges in the Zhitomir Region, after Gulyanka. Rovnoholoneurus gen. n. and two new species, Rovnoholoneurus davidi sp. n. and R. miyae sp. n. are described. Bryocrypta laqueata Fedotova, 2005 is transferred to the genus Rovnoholoneurus, and Rovnoholoneurus laqueatus (Fedotova, 2005), comb. n. is established. A key to the species of Rovnoholoneurus is provided.

scholarly journals The calcareous nannofossil <i>Prinsiosphaera</i> achieved rock-forming abundances in the latest Triassic of western Tethys: consequences for the δ<sup>13</sup>C of bulk carbonate

2013 ◽  
Vol 10 (5) ◽  
pp. 7989-8025 ◽  
Author(s):  
N. Preto ◽  
C. Agnini ◽  
M. Rigo ◽  
M. Sprovieri ◽  
H. Westphal
Keyword(s):  
Global Ocean ◽  
Late Triassic ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Western Tethys ◽  
Carbonate Sedimentation ◽  
History Of ◽  
Calcareous Plankton ◽  
Inorganic Carbon Cycle

Abstract. The onset of pelagic biomineralization marked a milestone in the history of the long term inorganic carbon cycle: as soon as calcareous nannofossils became major limestone producers, the pH and supersaturation state of the global ocean were stabilized (the so-called Mid Mesozoic Revolution). But although it is known that calcareous nannofossils were abundant already by the end of the Triassic, no estimates exist on their contribution to hemipelagic carbonate sedimentation. With this work, we estimate the volume proportion of Prinsiosphaera, the dominant Late Triassic calcareous nannofossil, in hemipelagic and pelagic carbonates of western Tethys. The investigated Upper Triassic lime mudstones are composed essentially of microspar and tests of calcareous nannofossils, plus minor bioclasts. Prinsiosphaera became a significant component of lime mudstones since the late Norian, and was contributing up to ca. 60% of the carbonate by the late Rhaetian in periplatform environments with hemipelagic sedimentation. The increasing proportion of Prinsiosphaera in upper Rhaetian hemipelagic lime mudstones is paralleled by a increase of the δ13C of bulk carbonate. We interpreted this isotopic trend as related to the diagenesis of microspar, which incorporated respired organic carbon with a low δ13C when it formed during shallow burial. As the proportion of nannofossil tests increased, the contribution of microspar with low δ13C diminished, determining the isotopic trend. We suggest that a similar diagenetic effect may be observed in many Mesozoic limestones with a significant, but not yet dominant, proportion of calcareous plankton.

Calcareous nannofossils from the Tasman Sea (IODP Site U1509): biochronology, paleoclimatic evolution and bulk stable isotopes across the Eocene-Oligocene Transition

2021 ◽  
Author(s):  
Allyson Viganò ◽  
Edoardo Dallanave ◽  
Laia Alegret ◽  
Thomas Westerhold ◽  
Rupert Sutherland ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
New Caledonia ◽  
Time Window ◽  
Principal Component ◽  
Diversity Indices ◽  
Late Eocene ◽  
Global Perspective ◽  
Carbonate Content ◽  
Calcareous Nannofossils ◽  
Deep Time

&lt;p&gt;About 34 Ma, the Warmhouse climate state switched into the Coolhouse state, when a rapid drop in temperature and the establishment of permanent continental ice-sheet on the Antarctic continent occurred (1).&lt;/p&gt;&lt;p&gt;This event, which is referred to as the Eocene-Oligocene transition (EOT; lasted ~500 ka) represents one of the most prominent transitions of the entire Cenozoic. During the EOT, calcareous nannoplankton experienced significant changes in the assemblage coinciding with the long-term cooling and modifications in the sea-surface water conditions (2, 3), suggesting a cause-effect relationship between the onset of the first sustained Antarctic glaciation and the response of phytoplanktonic communities.&lt;/p&gt;&lt;p&gt;We generated a high-resolution calcareous nannofossil and geochemical datasets (&amp;#948;&lt;sup&gt;18&lt;/sup&gt;O, &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C and % CaCO&lt;sub&gt;3&lt;/sub&gt;) from IODP Site U1509 (New Caledonia Trough) (4) with the final aim to provide an overview of the paleoclimatic and paleoceanographic evolution of the study area across the EOT. Our bio-magnetostratigraphic results, consistent with shipboard data (5), were compared along with other existing records recovered from Indian Ocean, Equatorial Pacific and Atlantic Ocean in order to critically evaluate the reliability, reproducibility and synchroneity of all the biohorizons taken into consideration and to obtain a clearer global perspective.&amp;#160;&lt;/p&gt;&lt;p&gt;According to major trends and shifts in the assemblage, the ~5 Myr study interval was subdivided into 4 distinct phases, which were also identified based on changes observed in 1) a number of diversity indices (i.e., species richness, dominance, H-index and evenness), 2) the warm-oligotrophic taxa abundance (&lt;em&gt;Discoaster saipanensis&lt;/em&gt;, &lt;em&gt;D. barbadiensis&lt;/em&gt; and &lt;em&gt;Ericsonia formosa&lt;/em&gt;), 3) the principal component (PC1 and PC2) scores, and 4) bulk stable isotopes and carbonate content. The observed changes are interpreted as an overall decline of warm-oligotrophic communities and, conversely, the incoming of genera better adapted to cooler and more eutrophic conditions.&lt;/p&gt;&lt;p&gt;The most prominent shift in the assemblage occurred during a time window of ~520 kyr, the precursor phase, with relatively high bulk &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O and % CaCO&lt;sub&gt;3&lt;/sub&gt; values, that predated the phase of maximum glacial expansion (Earliest Oligocene Glacial Maximum &amp;#8211; EOGM) (6) and documented the permanent loss of the late Eocene k-selected community, characterized by warm and oligotrophic taxa.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;1. T. Westerhold et al., Science. &lt;strong&gt;369&lt;/strong&gt;, 1383&amp;#8211;1388 (2020).&lt;/p&gt;&lt;p&gt;2. T. Dunkley Jones, P. R. Bown, P. N. Pearson, J. Syst. Palaeontol. &lt;strong&gt;7&lt;/strong&gt;, 359&amp;#8211;411 (2009).&lt;/p&gt;&lt;p&gt;3. H. K. Coxall, P. N. Pearson, in Deep-Time Perspectives on Climate Change: Marrying the Signal from Computer Models and Biological Proxies, Micropaleontology Society Special Publication, M. Williams, A. M. Haywood, J. Gregory, D. N. Schmidt, Eds. (Geological Society, London, 2007), pp. 351&amp;#8211;387.&lt;/p&gt;&lt;p&gt;4. R. Sutherland, G. R. Dickens, P. Blum, the Expedition 371, Int. Ocean Discov. Progr. (2017), doi:10.14379/iodp.pr.371.2018.&lt;/p&gt;&lt;p&gt;5. R. Sutherland et al., Tasman Front. Subduction Initiat. Paleogene Clim. Proc. Int. Ocean Discov. Program, 371 Coll. Station. TX (International Oce. &lt;strong&gt;371&lt;/strong&gt;, 1&amp;#8211;35 (2019).&lt;/p&gt;&lt;p&gt;6. Z. Liu, S. Tuo, Q. Zhao, X. Cheng, W. Huang, Chinese Sci. Bull. &lt;strong&gt;49&lt;/strong&gt;, 2190&amp;#8211;2197 (2004).&lt;/p&gt;

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