Some new and rarely documented Late Cretaceous calcareous nannofossils from subsurface sediments in South Carolina

1999 ◽  
Vol 73 (5) ◽  
pp. 952-963 ◽  
Author(s):  
Jean M. Self-Trail
Keyword(s):  
South Carolina ◽  
Upper Cretaceous ◽  
New Combination ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
East Central ◽  
Transmission Electron ◽  
Subsurface Sediments ◽  
Central South ◽  
Upper Campanian

One new calcareous nannofossil genus Senilatus; four new calcareous nannofossil species Calculites favosus, Lithraphidites? charactozorro Self-Trail and Pospichal, Rucinolithus oriens, and Watznaueria bybelliae; and one new combination, Senilatus zipperum n. gen. and comb., are described from Upper Cretaceous (upper Campanian to Maastrichtian) sediments of east-central South Carolina. These new species were described from five coreholes located in marine coastal plain deposits. There is evidence that the presence of one species, Senilatus zipperum, is indicative of nearshore, restricted environments. Scanning electron and light microscope pictures are provided for two species, Cretarhabdus multicavus Bukry, 1969 and Retemediaformis teneraretis Varol, 1991, that have previously been documented only with the transmission electron microscope. The ranges of these two species have been extended beyond those stated in the original descriptions.

scholarly journals Calcareous nannofossils from the upper Campanian–Maastrichtian (Upper Cretaceous) in the Kladorub Formation (Kula tectonic zone, NW Bulgaria)

2019 ◽  
Vol 48 (1) ◽  
pp. 73-101
Author(s):  
Georgi Granchovski
Keyword(s):  
Upper Cretaceous ◽  
Calcareous Nannofossils ◽  
Tectonic Zone ◽  
Lower Upper ◽  
Upper Maastrichtian ◽  
Stratigraphic Interval ◽  
Upper Campanian

A detailed investigation into the calcareous nannofossils from the upper Campanian–Maastrichtian deposits of the Kladorub Formation (NW Bulgaria) has been carried out in order to examine their taxonomic content and test the applicability of cosmopolitan zonation schemes for this stratigraphic interval in the country. The Kladorub Formation is composed of silty to fine-sandy marlstones and rare marly limestones, occasionally interbedded with sandstone layers. The recovered nannofloras are abundant, taxonomically diverse and exhibit predominantly moderate preservation, which allowed precise taxonomic identifications and biostratigraphic analysis to be made. As a result, the presence of two previously undocumented, biostratigraphically significant taxa has been recorded (i.e., Eiffellithus parallelus and Ceratolithoides kamptneri). Consequently, the studied Upper Cretaceous sediments have been assigned to subzone UC15dTP (pars.)–subzone UC20dTP; in the uppermost 2 m of the section, the presence of zone NP1 has also been indicated, which is in concordance with previous authors’ data. Due to the lack of proper chronostratigraphic framework for the Kladorub Formation, top Uniplanarius trifidus and base Lithraphidites quadratus have, respectively, been used to approximate the Campanian/Maastrichtian and lower/upper Maastrichtian boundaries. The Cretaceous/Palaeogene boundary, however, could not be drawn with precision, because it falls within a 6.5-m interval of non-exposure. The resulting biostratigraphic framework offers higher stratigraphic resolution than previously used local zonation schemes and allows correlation with coeval sedimentary successions from other parts of the Tethyan and Boreal realms.

Scanning and Transmission Electron Microscopy of Human Red Blood Cells

1969 ◽  
Vol 27 ◽  
pp. 44-45
Author(s):  
A.J. Tousimis ◽  
T.R. Padden
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Blood Cells ◽  
Room Temperature ◽  
Type Specimen ◽  
New Combination ◽  
Human Red Blood Cells ◽  
Transmission Electron ◽  
Microscope Slides ◽  
Scanning Electron

The size, shape and surface morphology of human erythrocytes (RBC) were examined by scanning electron microscopy (SEM), of the fixed material directly and by transmission electron microscopy (TEM) of surface replicas to compare the relative merits of these two observational procedures for this type specimen.A sample of human blood was fixed in glutaraldehyde and washed in distilled water by centrifugation. The washed RBC's were spread on freshly cleaved mica and on aluminum coated microscope slides and then air dried at room temperature. The SEM specimens were rotary coated with 150Å of 60:40- gold:palladium alloy in a vacuum evaporator using a new combination spinning and tilting device. The TEM specimens were preshadowed with platinum and then rotary coated with carbon in the same device. After stripping the RBC-Pt-C composite film, the RBC's were dissolved in 2.5N HNO3 followed by 0.2N NaOH leaving the preshadowed surface replicas showing positive topography.

An Ultrastructural Comparison of Hepatocytes from ADH+ and ADH−Peromyscus Maniculatus

1996 ◽  
Vol 54 ◽  
pp. 30-31
Author(s):  
J. T. Ellzey ◽  
D. Borunda ◽  
B. P. Stewart
Keyword(s):  
South Carolina ◽  
Adult Male ◽  
Uranyl Acetate ◽  
Model System ◽  
Deer Mice ◽  
En Bloc ◽  
Genetic Stock ◽  
Hepes Buffer ◽  
Transmission Electron ◽  
Color Scanner

Genetically alcohol deficient deer mice (ADHN/ADHN) (obtained from the Peromyscus Genetic Stock Center, Univ. of South Carolina) lack hepatic cytosolic alcohol dehydrogenase. In order to determine if these deer mice would provide a model system for an ultrastructural study of the effects of ethanol on hepatocyte organelles, 75 micrographs of ADH+ adult male deer mice (n=5) were compared with 75 micrographs of ADH− adult male deer mice (n=5). A morphometric analysis of mitochondrial and peroxisomal parameters was undertaken.The livers were perfused with 0.1M HEPES buffer followed by 0.25% glutaraldehyde and 2% sucrose in 0.1M HEPES buffer (4C), removed, weighed and fixed by immersion in 2.5% glutaraldehyde in 0.1M HEPES buffer, pH 7.4, followed by a 3,3’ diaminobenzidine (DAB) incubation, postfixation with 2% OsO4, en bloc staining with 1% uranyl acetate in 0.025M maleate-NaOH buffer, dehydrated, embedded in Poly/Bed 812-BDMA epon resin, sectioned and poststained with uranyl acetate and lead citrate. Photographs were taken on a Zeiss EM-10 transmission electron microscope, scanned with a Howtek personal color scanner, analyzed with OPTIMAS 4.02 software on a Gateway2000 4DX2-66V personal computer and stored in Excel 4.0.

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.

Late Mesozoic—Cenozoic clay mineral successions of southern Iran and their palaeoclimatic implications

Clay Minerals ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 191-203 ◽  
Author(s):  
F. Khormali ◽  
A. Abtahi ◽  
H. R. Owliaie
Keyword(s):  
Electron Microscopy ◽  
Upper Cretaceous ◽  
Sedimentary Rocks ◽  
X Ray Diffraction ◽  
Humid Climate ◽  
X Ray ◽  
Late Mesozoic ◽  
Southern Iran ◽  
Transmission Electron

AbstractClay minerals of calcareous sedimentary rocks of southern Iran, part of the old Tethys area, were investigated in order to determine their origin and distribution, and to reconstruct the palaeoclimate of the area. Chemical analysis, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and thin-section studies were performed on the 16 major sedimentary rocks of the Fars and Kuhgiluyeh Boyerahmad Provinces.Kaolinite, smectite, chlorite, illite, palygorskite and illite-smectite interstratified minerals were detected in the rocks studied. The results revealed that detrital input is possibly the main source of kaolinite, smectite, chlorite and illite, whilein situneoformation during the Tertiary shallow saline and alkaline environment could be the dominant cause of palygorskite occurrences in the sedimentary rocks.The presence of a large amount of kaolinite in the Lower Cretaceous sediments and the absence or rare occurrence of chlorite, smectite, palygorskite and illite are in accordance with the warm and humid climate of that period. Smaller amounts of kaolinite and the occurrence of smectite in Upper Cretaceous sediments indicate the gradual shift from warm and humid to more seasonal climate. The occurrence of palygorskite and smectite and the disappearance of kaolinite in the late Palaeocene sediments indicate the increase in aridity which has probably continued to the present time.

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