Halokinetic analysis of the Frade field area, Campos Basin, Brazil: Salt tectonics within an offshore strike-slip setting

2020 ◽  
Vol 8 (4) ◽  
pp. T869-T883
Author(s):  
Stephanie Wischer ◽  
Webster Mohriak

The Frade field, located within the Campos Basin in the southeastern Brazilian margin, is a key oil field that produces from Oligo-Miocene turbidite reservoirs that derived their structural positioning due to the presence of an underlying salt diapir. The evolution of the Frade salt structure was examined using well data, selected 2D lines, and a 3D volume that were interpreted in detail focusing on the Aptian evaporite interval and its influence on the overburden. Analysis of the salt-sediment interaction indicated a complex deformation history that included five main stages of deformation, some assisted by tectonic reactivation episodes. (1) Post-Albian reactivation of a nearby north–northwest-south–southeast basement fault caused the Albian carbonate interval to fault, forming a west–northwest-east–southeast shear zone with a dextral strike-slip component. This movement initiated thin-skinned tectonics that offset the Albian carbonates and formed a pull-apart basin that accommodated a thick Late Cretaceous interval, which weakened the overburden and allowed for the initial formation of the Frade salt diapir. (2) Renewed diapir growth thickened and redistributed the Cenomanian-Maastrichtian sedimentary package proximal to the Frade salt anticline. (3) An initial and localized collapse of the Frade salt anticline occurred during early Paleogene extension. (4) Paleogene shortening caused the salt to flow, resulting in salt withdrawal in the southeast and diapir rejuvenation near its present-day apex, forming several inversion structures. In addition, the Paleogene shortening resulted in a low-relief anticlinal structure that rotated the turbidites into geometries favoring hydrocarbon accumulation. (5) A return to an extensional regime occurred during the late Oligocene/early Miocene. The results of this study provide a new insight into the development of strike-slip salt tectonic structures and show for the first time within the Campos Basin an Albian-level pull-apart basin that formed in association with salt tectonics.

2007 ◽  
Author(s):  
Fernando Pacifico Figueiredo ◽  
Celso Cesar M. Branco ◽  
Fabio Prais ◽  
Marcelo Curzio Salomao ◽  
Cristina Cledia Mezzomo
Keyword(s):  

2004 ◽  
Vol 141 (5) ◽  
pp. 565-572 ◽  
Author(s):  
YUVAL BARTOV ◽  
AMIR SAGY

A newly discovered active small-scale pull-apart (Mor structure), located in the western part of the Dead Sea Basin, shows recent basin-parallel extension and strike-slip faulting, and offers a rare view of pull-apart internal structure. The Mor structure is bounded by N–S-trending strike-slip faults, and cross-cut by low-angle, E–W-trending normal faults. The geometry of this pull-apart suggests that displacement between the two stepped N–S strike-slip faults of the Mor structure is transferred by the extension associated with the normal faults. The continuing deformation in this structure is evident by the observation of at least three deformation episodes between 50 ka and present. The calculated sinistral slip-rate is 3.5 mm/yr over the last 30 000 years. This slip rate indicates that the Mor structure overlies the currently most active strike-slip fault within the western border of the Dead Sea pull-apart. The Mor structure is an example of a small pull-apart basin developed within a larger pull-apart. This type of hierarchy in pull-apart structures is an indication for their ongoing evolution.


2021 ◽  
Author(s):  
Vincent F. Verwater ◽  
Eline Le Breton ◽  
Mark R. Handy ◽  
Vincenzo Picotti ◽  
Azam Jozi Najafabadi ◽  
...  

Abstract. Neogene indentation of the Adriatic plate into Europe led to major modifications of the Alpine orogenic structures and style of deformation in the Eastern Alps. Especially, the offset of the Periadriatic Fault by the Northern Giudicarie Fault marks the initiation of strike-slip faulting and lateral extrusion of the Eastern Alps. Questions remain on the exact role of this fault zone in changes of the Alpine orogen at depth. This necessitates quantitative analysis of the shortening, kinematics and depth of decoupling underneath the Northern Giudicarie Fault and associated fold-and thrust belt in the Southern Alps. Tectonic balancing of a network of seven cross sections through the Giudicarie Belt parallel to the local shortening direction reveals that it comprises two kinematic domains with different amounts and partly overlapping ages of shortening. These two domains are delimitated by the NW-SE oriented strike-slip Trento-Cles – Schio-Vicenza fault system, cross-cutting the Southern Alpine orogenic front in the south and merging with the Northern Giudicarie Fault in the north. The SW kinematic domain (Val Trompia sector) accommodated at least ~18 km of Late Oligocene to Early Miocene shortening. Since the Middle Miocene, the SW kinematic domain experienced a minimum of ~12–22 km shortening, whereas the NE kinematic domain underwent at least ~25–35 km shortening. Together, these domains contributed to an estimated ~53–75 km of sinistral strike-slip motion along the Northern Giudicarie Fault, implying that (most of) the offset of the Periadriatic Fault is due to Late Oligocene to Neogene indentation of the Adriatic plate into the Eastern Alps. Moreover, the faults linking the Giudicarie Belt with the Northern Giudicarie Fault reach ~15–20 km depth, indicating a thick-skinned tectonic style of deformation. These fault detachments may also connect at depth with a lower crustal Adriatic wedge that protruded north of the Periadriatic Fault and was responsible for N-S shortening and eastward escape of deeply exhumed units in the Tauern Window. Finally, the east-west lateral variation of shortening indicates internal deformation and lateral variation in strength of the Adriatic indenter, related to Permian – Mesozoic tectonic structures and paleogeographic domains.


2021 ◽  
Author(s):  
Francyne B. Amarante ◽  
Christopher A-L. Jackson ◽  
Leonardo M. Pichel ◽  
Claiton M. S. Scherer ◽  
Juliano Kuchle

<p>Salt-bearing passive margin basins offshore SE Brazil have been and remain attractive for hydrocarbon exploration and production. In the Campos Basin, major reservoir types include post-salt turbidites, which are located in structural traps related to thin-skinned faulting above salt anticlines and rollers. Classic models of gravity-driven salt tectonics commonly depict kinematically linked zones of deformation, characterised by updip extension and downdip contraction, separated by a weakly deformed zone associated with downdip translation above a relatively smooth base-salt surface. We use 2D and 3D seismic reflection and borehole data from the south-central Campos Basin to show that this does not adequately capture the styles of salt-detached gravity-driven deformation above relict, rift-related relief. The base-salt surface is composed of elongated, broadly seaward-dipping ramps with structural relief reaching c. 2 km. These ramps define the boundary between the External High and the External Low, basement structures related to the rift tectonics. Local deformation associated with the base-salt ramps can overprint and/or influence regional, margin-scale patterns of deformation producing kinematically-variable and multiphase salt deformation. We define three domains of thin-skinned deformation: an updip extensional domain, subdivided into subdomains E1 and E2, an intermediate multiphase domain and a downdip contractional domain. The multiphase domain is composed of three types of salt structures with a hybrid extensional-contractional origin and evolution. These are: (i) contractional anticlines that were subjected to later extension and normal faulting; (ii) diapirs with passive and active growth later subjected to regional extension, developing landward-dipping normal faults on the landward flank; and, lastly, (iii) an extensional diapir that was subsequently squeezed. We argue that this multiphase style of deformation occurs as a consequence of base-salt geometry and relief creating local variations of salt flow that localize extension at the top and along the ramps, and contraction at the base. Translation and extension of salt and its overburden across major base-salt ramps resulted in three ramp syncline basins northeast of the study area, partially bounded by salt-detached listric faults. The temporal and spatial distribution and evolution of these and other key salt and overburden structures, and their relationship to base-salt relief, suggest 30 to 60 km of horizontal gravity-driven translation of salt and overburden.</p>


2018 ◽  
Vol 22 (4) ◽  
pp. 335-339
Author(s):  
Jingfeng Wu ◽  
Qi'an Meng ◽  
Xiaofei Fu ◽  
Yuling Ma ◽  
Meifeng Sun ◽  
...  

Fangzheng fault depression is controlled by the northern of the Tan-Lu fault zone. It undergoes multi-stage strike-slip, extrusion modification, and erosion of the thermal uplift, forming a tectonic pattern of uplifts connected with sags. Through the regional dynamic analysis, the study of the activity law of the western Pacific plate has clarified the formation and transformation of the regional tectonic stress field. Under the background of the multi-stage of the strike-slip mechanism in the northern part of the Tan-lu fault, the Fangzheng fault depression has a characteristic of the “left-lateral strike-slip pull-apart basin, right-lateral strike-slip extrusion transformation.” According to the difference of the strike-slip, the Fangzheng fault depression has divided into two parts: the East fault depression and the West fault depression. The seismic data, seismic attribute analysis, and geological modeling techniques have applied to analyze the two fault depressions, the East fault depression has actively controlled by the strike-slip activity, and the structure is complex. The seismic data quality is poor; the structure of the West Fault Depression is the opposite and structural characteristics of asymmetrical difference strike-slip in the East and West fault depressions. Interpretation of seismic sections through a slippery background, the strike-slip attributes of the whole fault depression from south to north are segmented, and the strike-slip mechanism from east to west is different. Under the control of the multi-stage strike-slip mechanism, the Fangzheng fault depression is divided into six stages of strike-slip evolution, corresponding to the six different stages of the strike-slip control basin, the formation process of the asymmetric difference strike-slip fault basin is clarified, which provides a reference for the study of the strike-slip pull-apart basin with multi-stage structure.


2017 ◽  
Vol 107 (2) ◽  
pp. 655-671 ◽  
Author(s):  
Manuel Martín-Martín ◽  
Antonio Estévez ◽  
Ivan Martín-Rojas ◽  
Francesco Guerrera ◽  
Francisco J. Alcalá ◽  
...  

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