scholarly journals The Registration of the Mid-Paleocene Biotic Event (MPBE) in Tunisia

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Narjess Karoui-Yaakoub ◽  
Moncef Saïd Mtimet ◽  
Mohamed Hédi Negra ◽  
Chaima Grira ◽  
Wafa Gusemi
Keyword(s):  
Iron Oxides ◽  
Deep Water ◽  
Surface Waters ◽  
Benthic Foraminifera ◽  
Rare Species ◽  
Planktonic Foraminifera ◽  
Dissolution Process ◽  
Dissolution Tests ◽  
First Time ◽  
El Haria Formation

In Tunisia, the Paleocene biomarkers are identified within the El Haria Formation shales. The Selandian is absent in most of the Paleocene outcrops and the Thanetian is unconformable to different stages of the Cretaceous. In the middle of Selandian, with the beginning of the Globanomalina pseudomenardii (P4) zone, we note that the assemblage of planktonic foraminifera becomes very poorly preserved and much less abundant than at the base. It is represented by rare species and there has been a start of the microfauna dissolution tests and an enrichment in iron oxides, silica, and gypsum crystals. The dissolution process is increasing more and more and a drop in the content of carbonates is clearly recorded at the top of Selandian. However, we note that some small benthic foraminifera belonging to the genera Lenticulina and Anomalina escape the dissolution and very few planktonic foraminifera belonging to the genera Subbotina are preserved. This dramatic and abnormal dissolution extends over a considerable thickness. These features could be an expression of the mid-Paleocene biotic event (MPBE), registered for the first time in Tunisia. This intense dissolution is caused probably by the change in the solubility of carbonates, which may be related to the changes in the deep-water circulation or to the change in the productivity of the surface waters.

scholarly journals Foraminiferal analysis and paleoenvironments of sediments in well -Aa, deepwater offshore, Niger Delta, Nigeria

2020 ◽  
Vol 26 (1) ◽  
pp. 9-14
Author(s):  
Umoh Ekaete Enamekere ◽  
Fasina Peace Oluwaseyi
Keyword(s):  
Deep Water ◽  
Late Miocene ◽  
Benthic Foraminifera ◽  
Niger Delta ◽  
Planktonic Foraminifera ◽  
Older Age ◽  
Outer Shelf ◽  
Depth Interval ◽  
Entire Interval ◽  
Agglutinated Foraminifera

Foraminiferal analysis was carried out on twenty five (25) ditch cutting samples from well -AA, offsore Niger Delta covering a depth interval of 9000ft-11025f. The study was aimed at age deduction, zoning the well, and interpreting the paleoenvironment of deposition. Lithostratigraphic description carried out on the sample revealed that the bulk lithofacies constitute shale with streaks of sand (fine-medium) between 9170ft - 9210ft and 9360ft -9380ft. The entire analysed interval was barren of planktonic foraminifera while depth 9960ft revealed a spot occurrence of Lagena spp,representing the only calcareous benthic foraminifera recovered in the entire interval. Few to common occurrences of deepwater agglutinated foraminifera were found in the well, dominated by some species of Haplophragmoides spp and Haplophragmoides narivaensis. Other foraminifera with rare and scattered occurrence includes, Cribrostomides spp, Bathysiphon spp, Troahammina spp, Cyclammina spp, Cyclammina cancellata, Valvulina spp, and Glomospira spp. The only microfaunal associated accessory recovered is ostracod at depth 1080ft. The analysed intervals was assigned a Middle – Late Miocene (N17 and older age) based on the FDO of Haplophragmoides narivaensis. The  environment of deposition is based on the distribution of typical deep water arenaeceous foraminifera species recovered in the study. The predominance of the arenaeceous forms over calcareous forms suggest outer shelf environment of deposition. Keywords: Foraminifera, Palaeoenvironment, Niger delta, Biostratigraphy.

Surface- and deep-water response to the Early Aptian OAE 1a in the western Tethys

2021 ◽  
Author(s):  
Cinzia Bottini ◽  
Victor M. Giraldo-Gómez ◽  
Maria Rose Petrizzo ◽  
Elisabetta Erba
Keyword(s):  
Deep Water ◽  
Surface Waters ◽  
Benthic Foraminifera ◽  
Bottom Water ◽  
Black Shales ◽  
Ontong Java Plateau ◽  
Western Tethys ◽  
Organic Carbon Flux ◽  
Water Response ◽  
Matter Flux

<p>The Cretaceous was punctuated by interludes of widespread deposition of organic-rich sediments (black shales) in the oceans and epicontinental seas, named Oceanic Anoxic Events (OAE)s, representing major alterations in the global carbon budget. The early Aptian OAE 1a (ca. 120 Ma) coincided with a global paleoclimatic and paleoenvironmental perturbation which lasted for ca. 1.1 Myrs probably triggered by volcanogenic CO<sub>2 </sub>emissions associated with the emplacement of the Ontong Java Plateau. To date, there is a comprehensive characterization of OAE 1a paleoceanographic conditions and paleoecology of surface-waters while less information is available for bottom-water evolution. In this regard, benthic foraminifera are ideal to characterize deep-water oxygen levels and the organic carbon flux. We present a high-resolution study of benthic foraminiferal assemblages across OAE 1a in the Cismon Core (western Tethys, Lombardy Basin, Northern Italy). Contrarily to many sites, the Cismon Core yields benthic foraminifera also in the Selli Level thus providing information about deep-water conditions during OAE 1a. Our data are indicative of fluctuations in bottom-water oxygenation and organic-matter flux to the sea-floor prior to, during and after OAE 1a. The integration of the new benthic foraminiferal data with calcareous nannofossil and planktonic foraminiferal datasets is here used to produce a model of surface- to bottom-water paleowater evolution through the latest Barremian-early late Aptian. In particular, the new data show coeval changes in bottom- and surface-waters conditions prior to and at the onset of OAE 1a. Anoxia was reached during the core of the negative carbon isotope anomaly, under maximum warming and higher surface-water fertility. Conversely, the repopulation of benthic foraminifera postponed the plankton recovery. Benthic foraminifera data at Cismon show, for the first time, evidence of a repopulation event during the OAE 1a suggestive for a slight increase in the supply of oxygen to the seafloor during the Selli Level deposition.</p>

scholarly journals The Campanian–Maastrichtian foraminiferal biostratigraphy of the basement sediments from the southern Pannonian Basin (Vojvodina, northern Serbia): implications for the continuation of the Eastern Vardar and Sava zones

2017 ◽  
Vol 68 (2) ◽  
pp. 130-146 ◽  
Author(s):  
Milena Dunčić ◽  
Ivan Dulić ◽  
Olivera Popov ◽  
Goran Bogićević ◽  
Alan Vranjković
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Pannonian Basin ◽  
Sedimentary Cover ◽  
Planktonic Foraminifera ◽  
Depositional Environments ◽  
Calcareous Nannoplankton ◽  
Southeastern Part ◽  
Geological Conditions ◽  
Shallow Water Sediments

Abstract Micropalaeontological and biostratigraphical studies included Campanian-Maastrichtian complexes from five oil exploration wells drilled in northern Serbia (Vojvodina): the first is a carbonate-clastic complex and second is a complex containing ophiolites intercalated with hemipelagic and pelagic sediments. Within the studied complexes, rich associations of planktonic and benthic foraminifera, calcareous nannoplankton, palynomorphs, as well as shallow and deep-water fossil detritus were determined. The presence of relatively rich associations of planktonic foraminifera allowed recognition of two biozones: the Globotruncana ventricosa Zone, observed in the sediments of the carbonate-clastic complex and the Gansserina gansseri Zone, observed in both complexes. Except biozones, based on documented index species, for some units in both complexes, larger benthic foraminifera species had special biostratigraphical value, and in some of them, the calcareous nannoplankton zones were recognized. The studied complexes represent deep-water formations, generated in oceanic island arc and trough zones. The presence of limestones, which originate from destroyed rudist reefs, is explained by transfer by means of gravitational transport mechanisms of shallow-water sediments to deep-water depositional environments. In this paper, the results of more detailed biostratigraphical and palaeo-ecological studies of foraminifera associations in Campanian-Maastrichtian complexes in Vojvodina are presented. Combined with lithological studies, seven units were determined within the complexes. The obtained results are important as a part of multidisciplinary, regional exploration of both complexes, generated in specific geological conditions, that today constitute a part of the pre-Neogene basement complex in the southeastern part of the Pannonian Basin. The Campanian- Maastrichtian carbonate-clastic complex represents sedimentary cover of the Eastern Vardar Ophiolitic Unit, while the ophiolites intercalated with hemipelagic and pelagic limestones belongs to the Sava Zone.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

Cyathodium denticulatum Udar et Srivastava: A rare liverwort new to Chhattisgarh, Central India

2020 ◽  
pp. 171-174
Author(s):  
Ashwini Kumar Dixit ◽  
Mery Aradhna Kerketta
Keyword(s):  
Rare Species ◽  
Biosphere Reserve ◽  
Central India ◽  
Himalayan Region ◽  
Taxonomic Description ◽  
First Time ◽  
Eastern Himalayan Region

This article reports the occurrence of the thalloid liverwort Cyathodium denticulatum Udar et Srivastava was collected first time from the Achanakmar – Amarkantak Biosphere Reserve (AABR) Bilaspur, Chhattisgarh. It is shown that Cyathodium denticulatum a narrow Himalayan endemic has been reported earlier from Darjeeling, India. There is no record of its occurrence from central India. Cyathodium denticulatum is a rare species known only from eastern Himalayan region. A key to related Indian taxa and taxonomic description is provided.

THE ABUNDANCE OF RECENT FORAMINIFERA IN SURFACE SEDIMENT OF AMBON BAY

2010 ◽  
Vol 2 (1) ◽  
Author(s):  
Suhartati M. Natsir
Keyword(s):  
Surface Sediment ◽  
Benthic Foraminifera ◽  
Sea Water ◽  
Planktonic Foraminifera ◽  
Sediment Characteristic ◽  
Abundance And Distribution

Foraminifera are generally live in sea water with various sizes. These organisms consist of planktonic and benthic foraminifera. Geological activity on plutonic and volcanic with vomiting magma is transpiring on, and then affects sedimentation and foraminiferal abundance of Ambon Bay. The study was determined to study the abundance and distribution of foraminifera based on the sediment characteristic of Ambon Bay. Sample collected in 2007 of Ambon Bay showed that only 29 samples of 50 samples containing foraminifera. The collected sediments have 86 species of foraminifera, consisting 61 species of benthic foraminifera and 25 species of planktonic foraminifera. The dominant benthic foraminifera in the surface sediment of Ambon bay were Amphistegina lessonii, Ammoniabeccarii,Elphidium craticulatum,Operculina ammonoides and Quinqueloculina parkery. The planktonic foraminifera that were frequently collected from the bay were Globorotalia tumida, Globoquadrina pseudofoliata, Globigerinoides pseudofoliata, Globigerinoides cyclostomus dan Pulleniatina finalis. Generally, the species dwelled as abundant on substrate sand, whereas the areas within substrate mud have no foraminifera lie on them. Keywords: Foraminifera, Abundance, Sediment, Ambon Bay

New records of some rare species in the family Hyaloscyphaceae (Ascomycota, Helotiales) from Central Russia

2013 ◽  
Vol 47 ◽  
pp. 135-142
Author(s):  
E. S. Popov
Keyword(s):  
Rare Species ◽  
New Records ◽  
Moscow Region ◽  
North Caucasus ◽  
Central Russia ◽  
The Family ◽  
First Time

Three rare species of discomycetes in the family Hyaloscyphaceae are reported from Central Russia (Oryol and Bryansk Regions). Proliferodiscus tricolor is recorded for the first time in Russia. Comments are made on Aeruginoscyphus sericeus and Eriopezia caesia previously reported only from Moscow Region and North Caucasus respectively.

Some new and interesting mosses (Bryophyta) from Republic of North Ossetia — Alania

2015 ◽  
Vol 49 ◽  
pp. 322-327
Author(s):  
G. Ya. Doroshina ◽  
I. A. Nikolajev ◽  
Yu. V. Lavrinenko
Keyword(s):  
Rare Species ◽  
The Republic ◽  
First Time ◽  
North Ossetia

Fissidens gracilifolius, Leptodontium flexifolium, Lindbergia dagestanica, Tortella bambergeri are recorded for the first time in the Republic of North Osetia — Alania. Rare species for the Republic are discussed: Fabronia ciliaris, F. pusilla, Lindbergia grandiretis, Tortula modica, Weissia wimmeriana, Zygodon rupestris.

To the moss flora of the highlands of the Northern Elbrus region (Central Caucasus)

2013 ◽  
Vol 47 ◽  
pp. 310-317 ◽  
Author(s):  
G. Ya. Doroshina
Keyword(s):  
New Species ◽  
Rare Species ◽  
The Caucasus ◽  
Central Caucasus ◽  
First Time

The list of 89 taxa of mosses from the northern slopes of Elbrus Mount is provided. New species for the region and rare species for the Caucasus are marked. Conostomum tetragonum (Hedw.) Lindb. was collected in the Caucasus for the first time.

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