Stratigraphy and Structural Features of the Continental Margin Basin of Senegal and Mauritania

1982 ◽  
pp. 160-181 ◽  
Author(s):  
Gerd Wissmann
Keyword(s):  
Continental Margin ◽  
Structural Features

Structural features of the Southwest African continental margin according to results of lithosphere-scale 3D gravity and thermal modelling

2013 ◽  
Vol 604 ◽  
pp. 104-121 ◽  
Author(s):  
Yuriy P. Maystrenko ◽  
Magdalena Scheck-Wenderoth ◽  
Alexander Hartwig ◽  
Zahie Anka ◽  
Antony B. Watts ◽  
...  
Keyword(s):  
Continental Margin ◽  
Structural Features ◽  
Thermal Modelling ◽  
3D Gravity

scholarly journals Structure of the Khatanga-Lomonosov fracture zone according to seismic data

2019 ◽  
Vol 487 (3) ◽  
pp. 304-309
Author(s):  
E. V. Shipilov ◽  
L. I. Lobkovsky ◽  
S. I. Shkarubo
Keyword(s):  
Continental Margin ◽  
Seismic Data ◽  
Data Interpretation ◽  
Structural Features ◽  
Laptev Sea ◽  
Lomonosov Ridge ◽  
Fracture Zones ◽  
Geodynamic Evolution ◽  
Eurasian Basin ◽  
The Laptev Sea

According to the results of geophysical data interpretation considered the structural features of the Khatanga-Lomonosov fracture zones (HLZ), adapted to the strip joint part on the Laptev Sea continental margin with the structures of the spreading of the Eurasian basin and the Lomonosov ridge. Its reflection in anomalous geophysical fields, in a wave seismic picture on sections is shown on the example of separate links of HLZ and the character of its kinematic interrelations with heterogeneous tectonic elements is illustrated. The tectonic nature, role and place of this fault zone in the geodynamic evolution of the region are substantiated.

scholarly journals On tectonic-geodynamic relationships of the Eurasian basin and the Lomonosov Ridge with the continental margin of Siberia according to new seismic data

2020 ◽  
pp. 34-42
Author(s):  
E.V. Shipilov ◽  
◽  
L.I. Lobkovsky ◽  
T.A. Kirillova ◽  
◽  
...  
Keyword(s):  
Continental Margin ◽  
Seismic Data ◽  
Sedimentary Cover ◽  
Structural Features ◽  
Lomonosov Ridge ◽  
Axial Zone ◽  
Gakkel Ridge ◽  
Development Scheme ◽  
Eurasian Basin ◽  
Stage Development

Basing on the results of the interpretation of new seismic materials, the authors consider the structural features of the southern segments of the Eurasian Basin and the Lomonosov Ridge in the zone of junction with the continental margin of Siberia (the Laptev and East Siberian Seas). Interpretative analysis of the materials shows that the base of the sedimentary cover of the southern segment of the Eurasian Basin, where there are no regular linear magnetic anomalies, is predominantly represented by strongly stretched blocks of the continental basement. The formation the axial zone of spreading of the Gakkel Ridge here took place according to a three-stage development scheme: rifting in the Aptian-Alba and its telescoping development in the Late Cretaceous — Paleocene-Eocene, inherited valley formation in late neotectonic time. The development of the Severny Basin located in the zone of junction of the Lomonosov Ridge with the continental margin is similar to the scenario for the formation of pull-apart basins. Its formation was interconnected with the simultaneously opening adjacent extreme southeastern segment of the Amundsen Basin of the Eurasian Basin.

Electron microscopy and diffraction studies of polyimides

1983 ◽  
Vol 41 ◽  
pp. 28-29
Author(s):  
O.C. de Hodgins ◽  
K. R. Lawless ◽  
R. Anderson
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Structural Features ◽  
Inert Atmosphere ◽  
Polyimide Films ◽  
Resolution Electron ◽  
The Matrix ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns ◽  
Polymeric Samples

Commercial polyimide films have shown to be homogeneous on a scale of 5 to 200 nm. The observation of Skybond (SKB) 705 and PI5878 was carried out by using a Philips 400, 120 KeV STEM. The objective was to elucidate the structural features of the polymeric samples. The specimens were spun and cured at stepped temperatures in an inert atmosphere and cooled slowly for eight hours. TEM micrographs showed heterogeneities (or nodular structures) generally on a scale of 100 nm for PI5878 and approximately 40 nm for SKB 705, present in large volume fractions of both specimens. See Figures 1 and 2. It is possible that the nodulus observed may be associated with surface effects and the structure of the polymers be regarded as random amorphous arrays. Diffraction patterns of the matrix and the nodular areas showed different amorphous ring patterns in both materials. The specimens were viewed in both bright and dark fields using a high resolution electron microscope which provided magnifications of 100,000X or more on the photographic plates if desired.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

Measurement and Reduction of Radiation Damage in Frozen Hydrated Crystalline Specimens

1978 ◽  
Vol 36 (3) ◽  
pp. 70-77 ◽  
Author(s):  
R.M. Glaeser ◽  
S.B. Hayward
Keyword(s):  
Diffraction Pattern ◽  
Structural Information ◽  
Structural Disorder ◽  
Structural Features ◽  
Biological Macromolecules ◽  
Diffraction Intensity ◽  
Object Structure ◽  
Specimen Material ◽  
Unit Cells ◽  
Identical Unit

Highly ordered or crystalline biological macromolecules become severely damaged and structurally disordered after a brief electron exposure. Evidence that damage and structural disorder are occurring is clearly given by the fading and eventual disappearance of the specimen's electron diffraction pattern. The fading and disappearance of sharp diffraction spots implies a corresponding disappearance of periodic structural features in the specimen. By the same token, there is a oneto- one correspondence between the disappearance of the crystalline diffraction pattern and the disappearance of reproducible structural information that can be observed in the images of identical unit cells of the object structure. The electron exposures that result in a significant decrease in the diffraction intensity will depend somewhat upon the resolution (Bragg spacing) involved, and can vary considerably with the chemical makeup and composition of the specimen material.

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