Planktonic foraminiferal species in Pacific sediments

1963 ◽  
Vol 10 (3) ◽  
pp. 349
Keyword(s):  
Foraminiferal Species

scholarly journals Meridional changes in the South Atlantic Subtropical Gyre during Heinrich Stadials

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tainã M. L. Pinho ◽  
Cristiano M. Chiessi ◽  
Rodrigo C. Portilho-Ramos ◽  
Marília C. Campos ◽  
Stefano Crivellari ◽  
...  
Keyword(s):  
Global Climate ◽  
South Atlantic ◽  
Subtropical Gyre ◽  
Climate System ◽  
The South ◽  
Foraminiferal Species ◽  
Ocean Gyres ◽  
Long Term Monitoring ◽  
Term Monitoring

AbstractSubtropical ocean gyres play a key role in modulating the global climate system redistributing energy between low and high latitudes. A poleward displacement of the subtropical gyres has been observed over the last decades, but the lack of long-term monitoring data hinders an in-depth understanding of their dynamics. Paleoceanographic records offer the opportunity to identify meridional changes in the subtropical gyres and investigate their consequences to the climate system. Here we use the abundance of planktonic foraminiferal species Globorotalia truncatulinodes from a sediment core collected at the northernmost boundary of the South Atlantic Subtropical Gyre (SASG) together with a previously published record of the same species from the southernmost boundary of the SASG to reconstruct meridional fluctuations of the SASG over last ca. 70 kyr. Our findings indicate southward displacements of the SASG during Heinrich Stadials (HS) 6-4 and HS1, and a contraction of the SASG during HS3 and HS2. During HS6-4 and HS1, the SASG southward displacements likely boosted the transfer of heat to the Southern Ocean, ultimately strengthening deep-water upwelling and CO2 release to the atmosphere. We hypothesize that the ongoing SASG poleward displacement may further increase oceanic CO2 release.

A new Antarctic foraminiferal species for detecting climate change in sub-Recent glacier-proximal sediments

2009 ◽  
Vol 21 (5) ◽  
pp. 439-448 ◽  
Author(s):  
Wojciech Majewski ◽  
Andrzej Tatur
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
The Arctic ◽  
South Shetland Islands ◽  
King George Island ◽  
Tidewater Glaciers ◽  
Admiralty Bay ◽  
Shetland Islands ◽  
Foraminiferal Species ◽  
Water Depths

AbstractCribroelphidium webbi sp. nov. is the only adequately described sub-Recent elphidiid foraminifer from Antarctica. In Admiralty Bay (King George Island, South Shetland Islands), it is found at several locations within inner fiord setting at water depths between 33 and 165 m, but most commonly shallower than 100 m. In outer basins this foraminifer is absent. In the cores analysed, C. webbi sp. nov. is present in well-constrained sub-Recent horizons that are clearly related to climate warming and deglaciation. These horizons represent a diachronous facies marker rather than a single stratigraphic layer. Cribroelphidium webbi sp. nov. shows clear association with retreating tidewater glaciers, therefore it is an important sensitive glacier-proximal indicator. It appears that it shares similar ecologic affinities with Cribroelphidium excavatum clavatum, which is widely distributed throughout the Arctic.

Taxonomic Re-Examination of the Late Cretaceous Planktonic Foraminiferal Species Archaeoglobigerina Cretacea (d'Orbigny, 1840) and Constraints on Its Morphologic Variability and Stratigraphic Distribution in One of The Type Localities (Kent, SE England)

2021 ◽  
Vol 51 (1) ◽  
pp. 46-63
Author(s):  
Francesca Falzoni ◽  
Annachiara Bartolini
Keyword(s):  
Late Cretaceous ◽  
Species Concept ◽  
Morphological Features ◽  
Single Individual ◽  
Type Specimens ◽  
Foraminiferal Species ◽  
Morphological Differences ◽  
Lower Campanian ◽  
Original Drawings

ABSTRACT Distinctive and taxonomically relevant morphological differences exist between the original drawings of Archaeoglobigerina cretacea illustrated by d'Orbigny (1840) and the lectotype designated by Banner & Blow (1960), particularly regarding the equatorial periphery, which is rounded in the former and double-keeled in the latter specimen. Such differences would suggest that they are not conspecific, but this hypothesis cannot be easily tested because d'Orbigny's drawings likely represent a synthesis of observations on several specimens rather than a single individual and the slide intended to contain the lectotype is empty. In this study, we have re-examined the A. cretacea type specimens deposited in the d'Orbigny collection at the Muséum National d'Histoire Naturelle in Paris and samples from one of the type localities (Kent, SE England) with the aim to reconstruct d'Orbigny's species concept, clarify its morphological features, and better constrain its stratigraphic distribution. Our study suggests that d'Orbigny's concept for A. cretacea was broad and included unkeeled as well as double-keeled morphotypes. However, assemblages from Kent yield common and large-sized specimens conspecific with the lectotype in the middle Santonian-lower Campanian, while morphotypes resembling the drawings of d'Orbigny are absent. Accordingly, five topotype specimens from the lower Campanian of Kent are herein illustrated in order to stabilize the species concept adopted over the last 60 years on the basis of the lectotype drawing and description. All topotypes possess a wide imperforate peripheral band and a moderately to weakly developed double-keeled periphery. Finally, the description of A. cretacea is emended to exclude specimens that do not possess an imperforate peripheral band and to include those that show curved and weakly beaded spiral sutures.

scholarly journals Geochemical characteristics from tests of four modern planktonic foraminiferal species in the Indonesian Throughflow region and their implications

2019 ◽  
Vol 10 (2) ◽  
pp. 505-516 ◽  
Author(s):  
Peng Zhang ◽  
Rina Zuraida ◽  
Yair Rosenthal ◽  
Ann Holbourn ◽  
Wolfgang Kuhnt ◽  
...  
Keyword(s):  
Geochemical Characteristics ◽  
Indonesian Throughflow ◽  
Foraminiferal Species

scholarly journals TAXONOMICAL CONSIDERATIONS, PHYLOGENY, PALEOGEOGRAPHY AND PALEOCLIMATOLOGY OF THE MIDDLE EOCENE (BARTONIAN) PLANKTIC FORAMINIFERA FROM JABAL HAFIT, AL AIN AREA, UNITED ARAB EMIRATES

2020 ◽  
Vol 4 (1) ◽  
pp. 10-20
Author(s):  
Haidar Salim Anan
Keyword(s):  
United Arab Emirates ◽  
Present Author ◽  
Middle Eocene ◽  
Planktic Foraminifera ◽  
Oman Mountains ◽  
Foraminiferal Species ◽  
Al Ain ◽  
Eastern Limb ◽  
First Time

The taxonomical consideration, probable phylogeny and stratigraphic significance of twenty-eight middle Eocene (Bartonian) planktic foraminiferal species from the eastern limb of Jabal Hafit, Al Ain area, United Arab Emirates (UAE), Northern Oman Mountains (NOM) are presented, and twenty one of them are illustrated. Identification of these twenty-eight species belonging to ten genera Globoturborotalia, Subbotina, Globigerinatheka, Inordinatosphaera, Orbulinoides, Hantkenina, Acarinina, Morozovelloides, Pseudohastigerina and Turborotalia has led to the recognition of three biostratigraphic zones, in ascending order: Morozovelloides lehneri PRZ (E11), Orbulinoides beckmanni TRZ (E12) and Morozovelloides crassata HOZ (E13). Eight out of the identified species are recorded, in this study, for the first time from Jabal Hafit: Globoturborotalia martini, Subbotina gortanii, S. jacksonensis, S. senni, Globigerinatheca barri, Acarinina praetopilensis, A. punctocarinata and Morozovelloides bandyi. The second or third record of three species from J. Hafit outside its original records are recently documented by the present author: Inordinatosphaera indica, Hantkenina australis and H. compressa. The paleontology, paleoclimatology and paleogeographic distribution of the identified taxa at Jabal Hafit and other Paleogene outcrops in the UAE and Tethys are presented and discussed. The identified fauna emphasis the wide geographic areas in the Tethys, from Atlantic to Indian-Pacific Oceans via Mediterranean.

scholarly journals Microfaunal Signals and Paleoenvironmental Reconstruction Sediments in Well Z-1, Offshore Dahomey Basin, South-Western Nigeria

2020 ◽  
pp. 50-61
Author(s):  
Anthonia Nwanese Asadu ◽  
Charles Ojonuba Ameh
Keyword(s):  
Gamma Ray ◽  
Accessory Mineral ◽  
Paleoenvironmental Reconstruction ◽  
Planktic Foraminifera ◽  
Rock Samples ◽  
Foraminiferal Species ◽  
Depositional Settings ◽  
Dahomey Basin ◽  
Abundance And Diversity ◽  
Gamma Ray Log

Fifty ditch cutting rock samples from well Z-1, OPL 310 offshore Dahomey basin, south western Nigeria were analyzed for their microfaunal and lithofacies content for the purpose of reconstructing the environment of deposition. Standard techniques of foraminifera slide processing and analysis was followed for the recovery of foraminifera while the gamma ray log complemented the rock samples for the lithofacies analysis. The lithological analysis revealed two lithofacies units in a generally fining upward sequence. The basal sandstone unit is characteristically milky white to brownish, coarse-pebbly grained, sub-angular to round and poorly to well sort with intercalation of shale. This unit is overlain by light to dark grey, moderately hard and non-fissile shale/mudstone sequence with intercalation of sand. Accessory mineral assemblage present in the formations includes mica flakes, glauconite pellets, carbonaceous detritus and ferruginous materials. The basal sandstone unit belong to the Oshosun Formation while the upper shaly unit is typical of Afowo Formation. Microfaunal study showed good recovery of abundant and well diversified planktic and benthic foraminiferal species. Forty-two (42) planktic, sixty-five (65) benthic calcareous and one benthonic arenaceous foraminiferal species were recovered. Micropaleontologically, Paleoenvironmental deductions were based primarily on the assemblage, abundance and diversity of benthic foraminiferal species and presence or absence of planktic foraminifera. Accessory mineral presence also aided the interpretations. Integration of lithological and micropaleontological synthesis enhanced the delineation of two environmental subzones over the analyzed interval, the outer neritic and the upper bathyal depositional settings corresponding to Afowo and Oshosun Formation respectively. A lowstand prograding wedge which is a good exploration target offshore was recognized between intervals 3400 ft to 3500 ft. In conclusion, the rock succession studied, penetrated Afowo and Oshosun Formations, and were deposited in an environment ranging from outer neritic to upper bathyal settings.

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