Elysium Region, Mars: Tests of lithospheric loading models for the formation of tectonic features

1986 ◽  
Vol 91 (B11) ◽  
pp. 11377 ◽  
Author(s):  
J. Lynn Hall ◽  
Sean C. Solomon ◽  
James W. Head
Keyword(s):  
Tectonic Features

scholarly journals Fissure Ridges: A Reappraisal of Faulting and Travertine Deposition (Travitonics)

Geosciences ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 278
Author(s):  
Andrea Brogi ◽  
Enrico Capezzuoli ◽  
Volkan Karabacak ◽  
Mehmet Cihat Alcicek ◽  
Lianchao Luo
Keyword(s):  
State Of The Art ◽  
Tectonic Setting ◽  
Original Data ◽  
Apical Part ◽  
Thermal Waters ◽  
Growth Mechanisms ◽  
Depositional Facies ◽  
Geothermal Fluids ◽  
Tectonic Features ◽  
Travertine Deposition

The mechanical discontinuities in the upper crust (i.e., faults and related fractures) lead to the uprising of geothermal fluids to the Earth’s surface. If fluids are enriched in Ca2+ and HCO3-, masses of CaCO3 (i.e., travertine deposits) can form mainly due to the CO2 leakage from the thermal waters. Among other things, fissure-ridge-type deposits are peculiar travertine bodies made of bedded carbonate that gently to steeply dip away from the apical part where a central fissure is located, corresponding to the fracture trace intersecting the substratum; these morpho-tectonic features are the most useful deposits for tectonic and paleoseismological investigation, as their development is contemporaneous with the activity of faults leading to the enhancement of permeability that serves to guarantee the circulation of fluids and their emergence. Therefore, the fissure ridge architecture sheds light on the interplay among fault activity, travertine deposition, and ridge evolution, providing key geo-chronologic constraints due to the fact that travertine can be dated by different radiometric methods. In recent years, studies dealing with travertine fissure ridges have been considerably improved to provide a large amount of information. In this paper, we report the state of the art of knowledge on this topic refining the literature data as well as adding original data, mainly focusing on the fissure ridge morphology, internal architecture, depositional facies, growth mechanisms, tectonic setting in which the fissure ridges develop, and advantages of using the fissure ridges for neotectonic and seismotectonic studies.

scholarly journals Pitfalls and limitations in seismic attribute interpretation of tectonic features

2015 ◽  
Vol 3 (1) ◽  
pp. SB5-SB15 ◽  
Author(s):  
Kurt J. Marfurt ◽  
Tiago M. Alves
Keyword(s):  
Seismic Data ◽  
Seismic Attributes ◽  
Seismic Attribute ◽  
3D Data ◽  
Amplitude Data ◽  
Seismic Sections ◽  
Push Down ◽  
Data Coherence ◽  
Level Of Experience ◽  
Tectonic Features

Seismic attributes are routinely used to accelerate and quantify the interpretation of tectonic features in 3D seismic data. Coherence (or variance) cubes delineate the edges of megablocks and faulted strata, curvature delineates folds and flexures, while spectral components delineate lateral changes in thickness and lithology. Seismic attributes are at their best in extracting subtle and easy to overlook features on high-quality seismic data. However, seismic attributes can also exacerbate otherwise subtle effects such as acquisition footprint and velocity pull-up/push-down, as well as small processing and velocity errors in seismic imaging. As a result, the chance that an interpreter will suffer a pitfall is inversely proportional to his or her experience. Interpreters with a history of making conventional maps from vertical seismic sections will have previously encountered problems associated with acquisition, processing, and imaging. Because they know that attributes are a direct measure of the seismic amplitude data, they are not surprised that such attributes “accurately” represent these familiar errors. Less experienced interpreters may encounter these errors for the first time. Regardless of their level of experience, all interpreters are faced with increasingly larger seismic data volumes in which seismic attributes become valuable tools that aid in mapping and communicating geologic features of interest to their colleagues. In terms of attributes, structural pitfalls fall into two general categories: false structures due to seismic noise and processing errors including velocity pull-up/push-down due to lateral variations in the overburden and errors made in attribute computation by not accounting for structural dip. We evaluate these errors using 3D data volumes and find areas where present-day attributes do not provide the images we want.

Seismic imaging of major tectonic features in the crust of Phanerozoic eastern Australia

1990 ◽  
Vol 173 (1-4) ◽  
pp. 211-230 ◽  
Author(s):  
D.M. Finlayson ◽  
K.D. Wake-Dyster ◽  
J.H. Leven ◽  
D.W. Johnstone ◽  
C.G. Murray ◽  
...  
Keyword(s):  
Seismic Imaging ◽  
Eastern Australia ◽  
Tectonic Features

Further Notes on Structural Types and Earth Movements

1931 ◽  
Vol 68 (1) ◽  
pp. 15-24
Author(s):  
J. S. Lee
Keyword(s):  
South Africa ◽  
North America ◽  
Critical Points ◽  
Eastern China ◽  
Point Of View ◽  
Continental Scale ◽  
Structural Types ◽  
Tectonic Features ◽  
Geological Magazine

In a previous paper published in the Geological Magazine, the writer made an attempt to discuss the mechanism of earth movement on a continental scale purely from a tectonic point of view. The problem is so vast and involved that some of the vital points were hardly touched upon, partly because of lack of space and partly of literature. The arrival of the admirable works of Dr. A. du Toit and Dr. E. Krenkel has enabled the writer to deduce the mechanism of the movements of South Africa directly from its tectonic features, which process is thought to be far more reliable than the type of argument used in the previous case although the results arrived at are essentially the same. The earlier movements in North America are now seen to furnish evidence of the same type of mechanism as that which staged the later movements. An epsilon type of structure has been recognized in Eastern China, which was then described as a mere arc. The problem of the distribution of concealed coalfields in England was in the previous paper barely touched upon. It is now proposed to consider some of the critical points bearing on the problem.

The significance of the boundary between the Rhoscolyn and New Harbour formations on Holy Island, North Wales, to the deformation history of Anglesey

2012 ◽  
Vol 150 (3) ◽  
pp. 519-535 ◽  
Author(s):  
JACK E. TREAGUS ◽  
SUSAN H. TREAGUS ◽  
NIGEL H. WOODCOCK
Keyword(s):  
Lower Cambrian ◽  
Depositional Environment ◽  
High Strain ◽  
The Other ◽  
Deformation History ◽  
Two Phase ◽  
Phase Deformation ◽  
North Wales ◽  
History Of ◽  
Tectonic Features

AbstractThe boundary between the Rhoscolyn and New Harbour formations on Holy Island, Anglesey, has been described as a high strain zone or as a thrust. The boundary is here described at four localities, with reference to the contrasting sedimentary and deformational character of the two formations. At one of these localities, Borth Wen, sandstones and conglomerates at the top of the Rhoscolyn Formation are followed, without any break, by tuffs and then mudstones of the New Harbour Formation. It is concluded that there is clear evidence of depositional continuity across the boundary here, and that both formations subsequently shared a common two-phase deformation. The first (D1) was manifestly different in intensity and scale in the two formations, whereas the second (D2) produced very similar structures in both. The other three localities provide continuity of sedimentary and tectonic features at this boundary in a traverse along the length of Holy Island, leading us to identify two previously unrecognized major D1 folds in addition to the Rhoscolyn Anticline. At one of these localities (Holyhead), we confirm the presence of Skolithos just below the boundary, supporting radiometric evidence for a lower Cambrian or later age for the Rhoscolyn Formation. A turbidite interpretation for both the Rhoscolyn and New Harbour formations best fits the available evidence. A deep-water depositional environment is still compatible with the sporadic presence of Skolithos burrows, but less so with reported observations of hummocky and swaley cross-stratification lower down the South Stack Group.

scholarly journals Novel Bathymetry of Lake Afdera Reveals Fault Structures and Volcano-Tectonic Features of an Incipient Transform Zone (Afar, Ethiopia)

2021 ◽  
Vol 9 ◽  
Author(s):  
Jean-Charles Schaegis ◽  
Valentin Rime ◽  
Tesfaye Kidane ◽  
Jon Mosar ◽  
Ermias Filfilu Gebru ◽  
...  
Keyword(s):  
Afar Depression ◽  
Nodal Basin ◽  
Bathymetric Data ◽  
The North ◽  
Transfer Zones ◽  
Fault Structures ◽  
Bathymetric Map ◽  
Endorheic Lake ◽  
Tectonic Features ◽  
Transfer Zone

Lake Afdera is a hypersaline endorheic lake situated at 112 m below sea-level in the Danakil Depression. The Danakil Depression is located in the northern part of the Ethiopian Afar and features an advanced stage of continental rifting. The remoteness and inhospitable environment explain the limited scientific research and knowledge about this lake. Bathymetric data were acquired during 2 weeks expeditions in January/February 2016 and 2017 using an easily deployable echosounder system mounted on an inflatable motorized boat. This study presents the first complete bathymetric map of the lake Afdera. Bathymetric results show that the lake has an average depth of 20.9 m and a total volume of 2.4 km3. The maximum measured depth is 80 m, making Lake Afdera the deepest known lake in Afar and the lowest elevation of the Danakil Depression. Comparison with historical reports shows that the lake level did not fluctuate significantly during the last 50 years. Two distinct tectonic basins to the north and the south are recognized. Faults of different orientations control the morphology of the northern basin. In contrast, the southern basin is affected by volcano-tectonic processes, unveiling a large submerged caldera. Comparison between the orientation of faults throughout the lake with the regional fault pattern indicates that the lake is part of two transfer zones: the major Alayta–Afdera Transfer Zone and the smaller Erta Ale–Tat’Ali Transfer Zone. The interaction between these Transfer Zones and the rift axis forms the equivalent of a developing nodal basin which explains the lake’s position as the deepest point of the depression. This study provides evidence for the development of an incipient transform fault on the floor of the Afar depression.

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