Book Description
This digital document is a journal article from Marine and Petroleum Geology, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Interpretation of regional seismic profiles, stratigraphic and sedimentologic data improved insights in the evolution of the Transylvanian Basin. The basin evolution was coeval with the post-Mid-Cretaceous to recent deformation of the Carpathian Mts. Four tectonostratigraphic megasequences are differentiated: Upper Cretaceous (rift), Paleogene (sag), Lower Miocene (flexural basin) and Middle to Upper Miocene (backarc sequence dominated by gravitational tectonics). The Mid-Miocene continental collision in the Eastern Carpathians is associated with the rising Carpathians. This uplift enhanced the differential load, which, together with the high heat flow induced by Late Miocene to Pliocene arc volcanism, triggered large-scale Mio-Pliocene gravity spreading of the salt overburden. This 'mega-slide' comprises three structural domains, as follows: extensional weld (upslope), contractional folds (central) and contractional toe thrust (downslope). The diapirs in the east indicate a pre-shortening reactive/passive growth stage. The central folds are mostly the result of late shortening. Basement involved thrusting uplifted the toe thrust domain by the Late Pliocene. The Late Neogene to recent Carpathians uplift, backarc volcanism and gravity spreading are largely coeval. ... Read more

Book Description
This digital document is a journal article from Marine and Petroleum Geology, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The Messinian evaporites in the Eastern Mediterranean represent a world class site to study thin-skinned salt tectonic processes like gravity gliding or gravity spreading. In contrast to the Mesozoic evaporites in the Atlantic the related structures are just slightly overprinted by additional tectonic events. New high-resolution reflection seismic data image for the first time the entire lateral succession of gravity gliding-related features as they were suggested by analog models and demonstrate therewith the validity of those models for the Messinian evaporites. All three regimes of extension, translation and compression are present within the range of the seismic profiles. However, additional observations lead to an adapted and improved model. The generation of a critical slope angle caused by subsidence of the Levantine Basin is considered to be the main driving force for the thin-skinned salt tectonics and the lateral basinward creep of the basinal Messinian evaporites. In the extensional section beneath or near to the continental slope, where the basinal evaporites have been withdrawn, listric and antithetic listric growth faults, rollovers and keystone grabens form asymmetric turtleback structures above salt welds and salt rollers. Further basinwards an area with little or no deformation of the evaporites defines the translational segment. In the compressional region the lower and thickest part of the evaporites show ductile deformation (buckle folds), and the upper evaporites reveal brittle deformation (reverse faults and pop-up structures). Here the basinal evaporites have a maximum thickness of about 1500m. The extensional zone shows continuous synsedimentary tectonic activity until recent times, whereas the compressional structures have developed later in a rather sudden event. There is clear evidence for neotectonics off the Israeli coast which is not related to salt dynamics. Faults cut through the entire pile of evaporites and the Post-Messinian overburden. Where the faults pierce the sea floor, mud escape structures have been observed. Deep rooted faults have been interpreted at the base of the Messinian paleo-slope, suggesting a shear zone off Israel and parallel to the Dead Sea Transform. ... Read more

Book Description
This digital document is a journal article from Marine and Petroleum Geology, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Structural analysis of the Nile deep-sea fan (NDSF) indicates that post-Miocene deformation is largely controlled by down-slope movement above a Messinian salt layer. In contrast to other similar systems, the NDSF shows significant lateral asymmetry, and three distinct provinces can be recognized. Regional variations in salt thickness and base-salt geometry within the system have led to the presence of structures typical of both gravity gliding and gravity spreading. Trends of structures within the western and central parts of the NDSF are consistent with forming due to gravity gliding processes. This pattern contrasts with that in the eastern NDSF that seem to be much more consistent with deformation due to gravity spreading. Observed differences in structural style across the NDSF can be related directly to the paleomorphological evolution of the Nile cone during Messinian time, which is perhaps partly related to features that have been inherited from early Mesozoic evolution of the North Egypt passive margin. In the east part of the NDSF, the structural evolution has been significantly influenced by the proximity of Eratosthenes Seamount. This large topographic buttress has served to both limit and deflect northeastward allochthonous advance of the Messinian evaporites and has thus severely complicated deformation of the overlying Plio-Quaternary sedimentary cover within the broad corridor that runs NNW-SSE and cuts obliquely across the modern bathymetry of the Nile cone. ... Read more

Book Description
This digital document is a journal article from Marine and Petroleum Geology, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The interaction between salt tectonics and sedimentation, offshore Angola has created a complex slope geometry of submarine channels, intra-slope basins and diapiric salt structures. There are a wide range of slope channel styles in close stratigraphic and geographic proximity, although the controls on these changes are not fully understood. Channels often follow complicated routes downslope, and have developed highly variable channel geometries, with narrow, erosional confined systems, and aggradational, broader systems as end members. Many channels are organised into stacked channel complexes. Rapid transitions in channel geometry are observed where channel systems pass through constrictions in salt wall structures or encounter decreases in slope gradients, for example within intra-slope depressions. Decreases in gradient and the exit points of incised channels mark the transition from narrow, well-defined linear or sinuous channels to broad, weakly confined channels. Important seismic facies changes are also observed where channels approach salt structures that created positive features on the seafloor. Results presented here show that linear, high gradient channels exhibit distinctive geometry changes around salt structures, often forming discreet depositional forms in planview. Lateral changes in sedimentary architecture within depositional lows record salt movement, as facies migrate relative to growing salt structures. ... Read more

Book Description
This digital document is a journal article from Marine and Petroleum Geology, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
A physical experiment shows that shortening applied to existing diapirs and minibasins produces anomalous structural styles that are unlike those of more typical foldbelts. Strong minibasins remain largely undeformed while weak diapirs localize contractional strain. Short diapirs form the cores to folds and thrusted folds, whereas tall diapirs are squeezed and often welded, commonly leading to the extrusion of allochthonous material. Key features of the model are observed in real examples. In the northern Gulf of Mexico passive margin, minibasins were originally separated by a polygonal pattern of deep salt ridges, with diapirs located at ridge intersections. Gravity spreading resulted in squeezed diapirs (and associated allochthonous salt) connected by variably oriented contractional, extensional, and strike-slip structures. In the Flinders Ranges convergent-margin foldbelt of South Australia, preexisting diapirs were squeezed, welded, and thrusted, with anticlines plunging away in multiple directions, so that minibasins are surrounded by highly variable structures. A different geometry is observed in La Popa Basin, Mexico, where squeezing of a linear salt wall produced a vertical weld with diapirs at the terminations, rather than the culmination. In all areas, foldbelt geometries are strongly influenced by the preestablished salt-minibasin architecture. ... Read more

Book Description
This digital document is a journal article from Marine and Petroleum Geology, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
We integrated structural analysis of multichannel seismic data and isopach maps of the Quaternary sedimentary cover to evaluate how salt tectonics has influenced the stratigraphic evolution offshore the Gulf of Lions. The interplay between salt tectonics and sedimentation occurs at two scales. At local scale, listric normal faults create bathymetric relief able to deviate sediment transport axes, with implications on depocenters configuration. At depocenter scale, overburden vertical movements due to salt evacuation or salt diapiric rise create sub-basins, providing accommodation space for clastic deposition. These mechanisms have significant implications on the architecture and the internal organization of turbidite systems offshore the Gulf of Lions. ... Read more

Book Description
This digital document is a journal article from Marine and Petroleum Geology, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The Nile deep turbiditic system displays many fluid-releasing structures on the seabed: mud volcanoes reassembling small cones (100-900 m in diameter), mud pies (5 km in diameter), and pockmarks. The cones are restricted to the western province. Mud 'pies' delineate a belt of apparently very active gas chimneys along the upper continental slope. Pockmarks are associated either with strongly destabilized sedimentary masses or with gas chimneys. We distinguish five main controlling parameters interacting in fluid release locations: (1) the presence, at depth, of potential source rocks and reservoirs; (2) the distribution of Messinian evaporites preventing upward fluid migration; (3) the distribution of sedimentary overloading inducing localized overpressures on under-compacted and fluid-rich sediments; (4) the presence of syn-sedimentary faults acting as potential conduits for fluid migration; and finally (5) chiefly for pockmarks and mounds, the occurrence of large-scale sedimentary instabilities. ... Read more

Book Description
This digital document is a journal article from Marine and Petroleum Geology, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Based on new ('SESAME 01' cruise) and previous seismic reflection data, this paper evidences the effects of the Messinian Salinity Crisis on the sedimentation at the western Sardinian margin. In the lower part of the margin, Messinian detrital deposits are organized into two successive, ~300m thick units. According to their shape, facies and extent, they are similar to alluvial fans, presumably fed by subaerial erosion of the upper margin. Whereas the earliest body is observed continuously all along the margin and the adjacent part of the deep basin, the youngest one is restricted to the vicinity of the canyons. This pattern could therefore sign a late Messinian sea-level rise, as suggested by detrital fan conglomerates sampled in a similar position along the northern Ligurian margin. We observe salt-related deformation of the Messinian detrital units, and the top of the salt layer gradually turn into a detrital delta seaward, implying that at the deep margin, most of the salt deposited before the low-stand Messinian delta emplaced, probably during the main Messinian sea-level drop or at the beginning of the low-stand sea-level. ... Read more

Book Description
This digital document is a journal article from Marine and Petroleum Geology, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The interaction between salt tectonics and sedimentation, offshore Angola has created a complex slope geometry of submarine channels, intra-slope basins and diapiric salt structures. There are a wide range of slope channel styles in close stratigraphic and geographic proximity, although the controls on these changes are not fully understood. Channels often follow complicated routes downslope, and have developed highly variable channel geometries, with narrow, erosional confined systems, and aggradational, broader systems as end members. Many channels are organised into stacked channel complexes. Rapid transitions in channel geometry are observed where channel systems pass through constrictions in salt wall structures or encounter decreases in slope gradients, for example within intra-slope depressions. Decreases in gradient and the exit points of incised channels mark the transition from narrow, well-defined linear or sinuous channels to broad, weakly confined channels. Important seismic facies changes are also observed where channels approach salt structures that created positive features on the seafloor. Results presented here show that linear, high gradient channels exhibit distinctive geometry changes around salt structures, often forming discreet depositional forms in planview. Lateral changes in sedimentary architecture within depositional lows record salt movement, as facies migrate relative to growing salt structures. ... Read more