scholarly journals Giant meandering channel evolution, Campos deep-water salt basin, Brazil

Geosphere ◽  
2021 ◽  
Author(s):  
Jacob A. Covault ◽  
Zoltán Sylvester ◽  
Can Ceyhan ◽  
Dallas B. Dunlap
Keyword(s):  
Migration Rate ◽  
Migration Pattern ◽  
Sediment Supply ◽  
Southeastern Brazil ◽  
Channel System ◽  
Meandering Channel ◽  
Campos Basin ◽  
And Migration ◽  
Channel Deposits ◽  
Basin Fill

Submarine channels are conduits for sediment delivery to continental margins, and channel deposits can be sandy components of the fill in tectonically active salt basins. Examples of salt-withdrawal basin fill commonly show successions of sandy channelized or sheet-like systems alternating with more mud-rich mass-transport complexes and hemipelagites. This alternation of depositional styles is controlled by subsidence and sediment-supply histories. Salt-basin fill comprising successions of largely uninterrupted meandering-channel deposition are less commonly recognized. This begs the questions: can sediment supply be large enough to overwhelm basin subsidence and result in a thick succession of channel deposits, and, if so, how would such a channel system evolve? Here, we use three-dimensional seismic-reflection data from a >1500 km2 region with salt-influenced topography in the Campos Basin, offshore Brazil, to evaluate the influence of salt diapirs on an Upper Cretaceous–Paleogene giant meandering submarine-channel system (channel elements >1 km wide; meander wavelengths several kilometers to >10 km). The large scale of the channels in the Campos Basin suggests that sediment discharge was large enough to sustain the meandering channel system in spite of large variability in subsidence across the region. We interpreted 22 channel centerlines to reconstruct the detailed kinematic evolution of this depositional system; this level of detail is akin to that of recent studies of meandering fluvial channels in time-lapse Landsat satellite images. The oldest channel elements are farther from salt diapirs than many of the younger ones; the centerlines of the older channel elements exhibit a correlation between curvature and migration rate, and a spatial delay between locations of peak curvature and maximum migration distance, similar to that observed in rivers. As many of the younger channel centerlines expanded toward nearby salt diapirs, their migration pattern switched to downstream translation as a result of partial confinement. Channel segments that docked against salt diapirs became less mobile, and, as a result, they do not show a correlation between curvature and migration rate. The channel migration pattern in the Campos Basin is different compared to that of a tectonically quiescent continental rise where meander evolution is unobstructed. This style of channelized basin filling is different from that of many existing examples of salt-withdrawal minibasins that are dominated by overall less-channelized deposits. This difference might be a result of the delivery of voluminous coarse sediment and high discharge of channel-forming turbidity currents to the Campos Basin from rivers draining actively uplifting coastal mountains of southeastern Brazil. Detailed kinematic analysis of such well-preserved channels can be used to reconstruct the impact of structural deformation on basin fill.

scholarly journals Giant meandering channel systems controlled by sediment supply to the deep-water Campos basin

2019 ◽  
Author(s):  
Jacob Covault ◽  
Zoltan Sylvester ◽  
Daniel Carruthers ◽  
Dallas Dunlap
Keyword(s):  
Deep Water ◽  
Sediment Supply ◽  
Meandering Channel ◽  
Campos Basin ◽  
Channel Systems

A radioautographic analysis of the migration and fate of cells derived from the occipital somites in the chick embryo with specific reference to the development of the hypoglossal musculature

Development ◽  
1970 ◽  
Vol 24 (3) ◽  
pp. 455-466
Author(s):  
R. D. Hazelton
Keyword(s):  
Chick Embryo ◽  
Dorsal Surface ◽  
Lateral Position ◽  
Migration Pattern ◽  
Specific Reference ◽  
Specific Marker ◽  
Differential Growth ◽  
Pericardial Cavity ◽  
And Migration ◽  
Pharyngeal Area

The migration pattern and fate of cells of the occipital somites and overlying ectoderm have been described for the chick embryo with particular reference to the development of the hypoglossal musculature. Tritium-labelled thymidine (0·5–10 µCi per egg) was used as a cell-specific marker. Occipital somites (2–5) with overlying ectoderm were transplanted orthotopically from labelled donor embryos to unlabelled host embryos (Hamburger & Hamilton, stage 9–10). The embryos were incubated, for varying lengths of time (24 h-5 days), sacrificed, sectioned and the migration pattern and fate of the labelled cells determined radioautographically. It appears that the hypoglossal as well as other hypopharyngeal musculature originates from the occipital somites. The mesodermal migration pattern extended from the occipital somite region in a ventroposterior direction to the dorsal surface of the pericardial cavity posterior to the expanded portion of the pharynx. At this position a so-called hypoglossal cord formed on each side which ran anteriorly to the level of the second pharyngeal pouch where it turned medially and together with the cord from the other side entered the pharyngeal area of the embryo. This material apparently forms the intrinsic musculature of the tongue. The mesodermal movements are attributed to differential growth movements of the areas concerned as well as to active cell mutiplication and migration. Selective embryonic neuronal staining was undertaken to study the relationship between the migrating hypoglossal cord and nerve. The cord preceded the nerve in its migration. There is an occipital somitic contribution to the primitive meninx, to the endothelial walls of developing blood vessels, possibly to microglial cells and to the cartilage surrounding the notocord. The occipital ectoderm expands dorso-anteriorly and ventro-laterally. In the ventro-lateral position as contact is made with the pharyngeal endoderm a placode is formed which contributes cells to the nodose ganglion of the tenth cranial nerve. There is no other contribution of the ectoderm to the underlying tissues.

scholarly journals RS CVn STARS: Photospheric Phenomena and Rotation

1983 ◽  
Vol 71 ◽  
pp. 343-361
Author(s):  
S. Catalano
Keyword(s):  
Migration Rate ◽  
Orbital Motion ◽  
Rotation Period ◽  
Maximum Amplitude ◽  
Activity Level ◽  
Period 2 ◽  
Rs Cvn Stars ◽  
Activity Cycles ◽  
And Migration ◽  
Wave Migration

ABSTRACTThis review presents a summary of observed photospheric phenomena on RS CVn stars: the amplitude, shape, evolution and migration rate of the photometric wave in relation to the rotational and orbital motion.The main points considered are: 1) the activity level (maximum amplitude, short and long timescale variability) versus rotation period; 2) the activity cycles as inferred from changes in the wave migration rate and direction and from the variation of its amplitude; 3) the detection of differential rotation; 4) the connection between the orbital period variation and activity.

scholarly journals The Alegre Lineament and its role over the tectonic evolution of the Campos Basin and adjacent continental margin, Southeastern Brazil

2016 ◽  
Vol 69 ◽  
pp. 226-242 ◽  
Author(s):  
Salomão Silva Calegari ◽  
Mirna Aparecida Neves ◽  
Felipe Guadagnin ◽  
George Sand França ◽  
Maria Gabriela Castillo Vincentelli
Keyword(s):  
Continental Margin ◽  
Tectonic Evolution ◽  
Southeastern Brazil ◽  
Campos Basin

Coherency Strain Energy in any Crystal System: Applications to in Situ Observations of Cigm in Calcite

1990 ◽  
Vol 205 ◽  
Author(s):  
R.S. May ◽  
B. Evans
Keyword(s):  
Driving Force ◽  
Migration Rate ◽  
Strain Energy ◽  
Solute Concentration ◽  
Coherency Strain ◽  
Solute Diffusion ◽  
Boundary Orientation ◽  
In Situ Observations ◽  
And Migration

AbstractIn situ observations of CIGM in CaCO3 bicrystals with a SrCO3 solute source were made. The change in boundary orientation and migration rate were compared with solute concentration. The liquid film model for coherency strain Induced migration was generalized to any non-cubic system and applied to CaCO3-SrCO3. The coherent layer was modeled as a thin film on an infinite half-space. The strain energy was found from solution of the Hooke's law expressions transformed to the appropriate coordinate system. For triclinic or monoclinic films the strain tensor was found by an eigenvector decomposition of the transformation matrix that defined the lattice parameter change with composition. High anisotropy of Vegard's law constants for CaCO3-SrCO3 caused (111) to have the lowest coherency strain per unit solute. Surfaces perpendicular to (111) in coherent equilibria were predicted to have half the solute concentration and three times the migration driving force of those perpendicular to (111). However, no correlation between solute concentration and boundary orientation was observed. Ambiguous and contradictory evidence for a relationship between solute concentration, boundary orientation, and migration rate was found. The self-stress state of a grain boundary in a solute diffusion field may be better modelled as hydrostatic rather than plane stress. Hydrostatic compression may interact with the boundary excess volume and cause a PV driving force for migration. Predictions based on coherent equilibrium at a surface have not been tested for that geometry in calcite; they should be tested before they are applied to grain boundaries.

EUS-guided gold fiducial placement and migration rate

2014 ◽  
Vol 80 (3) ◽  
pp. 533-534 ◽  
Author(s):  
Lorenzo Fuccio ◽  
Gabriele Lami ◽  
Alessandra Guido ◽  
Carlo Fabbri
Keyword(s):  
Migration Rate ◽  
And Migration

Four new species of Polycirrus Grube, 1850 (Polychaeta: Terebellidae) from Campos Basin, southeastern Brazil

Zootaxa ◽  
2013 ◽  
Vol 3626 (1) ◽  
pp. 146-172
Author(s):  
ORLEMIR CARRERETTE ◽  
JOÃO MIGUEL DE MATOS NOGUEIRA
Keyword(s):  
New Species ◽  
Rio De Janeiro ◽  
Environmental Heterogeneity ◽  
Southeastern Brazil ◽  
Brazilian Coast ◽  
Campos Basin

Four new species of Polycirrus were collected at the Campos Basin, state of Rio de Janeiro, during a survey coordinated by CENPES/PETROBRAS under the scope of the project, "Environmental Heterogeneity in the Campos Basin". These species are P. nonatoi sp. nov., P. papillosus sp. nov., P. breviuncinatus sp. nov., and P. habitats sp. nov. All these species are herein described and compared with the morphologically most similar congeners. In addition, a key is provided for the identification of the species of Polycirrus which have been originally described for the Brazilian coast.

Tectonic framework of the Barra de São João Graben, Campos Basin, Brazil: Insights from gravity data interpretation

2014 ◽  
Vol 2 (4) ◽  
pp. SJ65-SJ74 ◽  
Author(s):  
Leandro B. Adriano ◽  
Paulo T. L. Menezes ◽  
Alan S. Cunha
Keyword(s):  
Gravity Data ◽  
Shear Zones ◽  
Data Interpretation ◽  
Fault System ◽  
Magnetic Data ◽  
Southeastern Brazil ◽  
Rift System ◽  
Seismic Line ◽  
Structural Framework ◽  
Campos Basin

The Barra de São João Graben (BSJG), shallow water Campos Basin, is part of the Cenozoic rift system that runs parallel to the Brazilian continental margin. This system was formed in an event that caused the reactivation of the main Precambrian shear zones of southeastern Brazil in the Paleocene. We proposed a new structural framework of BSJG based on gravity data interpretation. Magnetic data, one available 2D seismic line, and a density well-log of a nearby well were used as constraints to our interpretation. To estimate the top of the basement structure, we separated the gravity effects of deep sources from the shallow basement (residual anomaly). Then, we performed a 2D modeling exercise, in which we kept fixed the basement topography and the density of the sediments, to estimate the density of the basement rocks. Next, we inverted the residual anomaly to recover the depth to the top of the basement. This interpretation strategy allowed the identification of a complex structural framework with three main fault systems: a northeast–southwest-trending normal fault system, a northwest–southeast-trending transfer fault system, and an east–west-trending transfer fault system. These trends divided the graben into several internal highs and lows. Our interpretation was corroborated by the magnetic anomalies. The existence of ultradense and strongly magnetized elongated bodies in the basement was interpreted as ophiolite bodies that were probably obducted by the time of the shutdown of the Proterozoic Adamastor Ocean.

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