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Book ChapterDOI

Structural Reorganization of the India-Arabia Strike-Slip Plate Boundary (Owen Fracture Zone; NW Indian Ocean) 2.4 million years ago

01 Jan 2019-pp 145-155

AbstractThe Owen fracture zone (OFZ) is the present day, 800-km-long dextral India-Arabia plate boundary, with conspicuous pull-apart basins at stepover areas and at its terminations. We summarize geological evidence documenting the age of formation of the OFZ, based on detailed analysis of geophysical and drilling data in the vicinity of the main pull-apart basins. Although India-Arabia motion started in the Late Cretaceous, we show that the present-day OFZ is a young structure formed at 2.4 Ma. This last structural reorganization of the India-Arabia plate boundary is unrelated to any well-documented kinematic change, leaving questions over its driver.

Topics: Fracture zone (56%), Transform fault (51%), Pull apart basin (50%), Plate tectonics (50%)

Summary (2 min read)

1 -Introduction

  • Using multibeam and seismic data, tied to nearby ODP-DSDP sites, the authors performed detailed structural and stratigraphic studies to investigate the age of formation of each major structure (mainly pull-apart basins) observed along the OFZ in order to determine its age of formation.
  • The results show that the present-day expression of the entire, 800-km-long OFZ formed at 2.4 Ma, from the Aden-Owen-Carlsberg triple junction to the Makran subduction zone (Fig. 1 ) and involved the opening of conspicuous pull-apart basins (from south to north: the Beautemps-Beaupré Basin, Fig. 2 ; the 20° N Basin, Fig. 3 ; the Dalrymple Trough, Fig. 4 ).

2.1 The Indus Turbiditic Channels

  • In terms of relative chronology, the turbiditic channels observed west of the OFZ (in the Owen Basin) predate its formation and indicate a period of limited tectonic activity, or a period when sedimentation rates were too high to record tectonics.
  • East of the OFZ, the turbiditic channels trapped or deviated by strike-slip structures postdate the formation of the OFZ.
  • Dating the different turbiditic systems provides good age brackets for the formation of the OFZ.
  • The age of a turbiditic channel is estimated from the age of the first pelagic layer that covers it.

2.2 Fault-Controlled Contourite Drifts

  • Bottom currents influence the geometry of deep-sea sedimentary deposits and build conspicuous sedimentary formations referred to as contourite drifts (Rebesco et al., 2014) .
  • In the vicinity of the OFZ, several fault-controlled contourite drifts are observed within the pelagic blanket lying over the turbiditic channels (Figs. 3 and 4 ).
  • The opening of pull-apart basins along the OFZ induced local perturbations of bottom current.
  • The base of a fault-controlled drift indicates the minimum age of formation of the fault.

2.3 Angular Unconformities

  • Vertical motion of the seafloor (uplift or subsidence) related to faults results in major angular unconformities within the Indus fan, sometimes outlined by conspicuous fanning configurations recording the growth of the structure.
  • Within the fanning configurations, numerous unconformities reflect the control of sealevel variations at the 105 years time-scale over the Indus fan sedimentation (Bourget et al., 2013) .

3 -AGE OF STRUCTURES ALONG THE OWEN FRACTURE ZONE

  • The Beautemps-Beaupré Basin is almost entirely filled in by Indus turbidites.
  • This unconformity can be tracked within the Beautemps-Beaupré Basin, where it coincides with the onset of lateral variations in thickness of turbidites, which marks the onset of seafloor subsidence there.
  • Since its uplift above the level of turbidites deposition, the Beautemps-Beaupré Ridge is blanketed by pelagic sediments that can be correlated with pelagic sediments on top of the nearby Owen Ridge (Fig. 2 ), where ODP sites provide stratigraphic constraints (Discoaster pentaradius; Shipboard Scientific Party, 1989).

3.2 The 20°N Pull-Apart Basin

  • The OFZ constitutes the western flank of the 20° N Basin, while imbricated systems of arcuate normal faults dissect its eastern flank (Fig. 3 ).
  • Fossil turbidite channels are identified west of the basin, whereas the currently active channel is captured on the eastern side of the basin (Rodriguez et al., 2011; Bourget et al., 2013) .
  • The opening of the basin may have disturbed the course of the bottom current and triggered the building of the drift.
  • The reflector marking the base of the drift can be correlated within the pelagic cover as far as the ODP sites located at the top of the Owen Ridge.

4 -DISCUSSION AND PERSPECTIVES

  • Detailed tectono-stratigraphic studies indicate the present-day configuration of the entire 800-km-long OFZ formed at 2.4 Ma, expressed by the coeval opening of the Beautemps-Beaupré basin to the south, the 20° N basin, and the Dalrymple Trough to the north.
  • Ma does not correspond to a clearly identified kinematic change (DeMets et al., 2017) , making the geodynamic driver of its formation unknown.
  • Either the corresponding kinematic change has not been detected so far, or there is no kinematic change related to the onset of the OFZ.
  • The formation of the OFZ may simply be the last step of a series of transient adjustments of the India-Arabia plate boundary since the last major kinematic change identified in the Indian Ocean between 6 and 8 Ma (DeMets and Merkouriev, 2016; DeMets et al., 2017) .
  • It is also possible that the 2.4 Ma episode of intensification of the Indian Monsoon (An et al., 2001) might have played a role in the evolution of the strike-slip system through its effect on the Indus sedimentation rates (increase up to 500 m/Ma at 2.4 Ma; Shipboard Scientific Party, 1989).

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Structural reorganization of the India-Arabia strike-slip
plate boundary (Owen Fracture Zone; NW Indian
Ocean) 2.4 million years ago
Mathieu Rodriguez, Philippe Huchon, Nicolas Chamot-Rooke, Marc Fournier,
Matthias Delescluse
To cite this version:
Mathieu Rodriguez, Philippe Huchon, Nicolas Chamot-Rooke, Marc Fournier, Matthias Delescluse.
Structural reorganization of the India-Arabia strike-slip plate boundary (Owen Fracture Zone; NW
Indian Ocean) 2.4 million years ago. Joao C. Duarte. Transform Plate Boundaries and Fracture Zones,
Elsevier, pp.146-155, 2019, �10.1016/B978-0-12-812064-4.00007-4�. �hal-02326725�

CHAPTER 7
Structural reorganization of the India-Arabia
strike-slip plate boundary (Owen Fracture
Zone; NW Indian Ocean) 2.4 million years ago
Mathieu Rodriguez
1
Philippe Huchon
2
Nicolas Chamot-Rooke
1
Marc Fournier
2
Matthias Delescluse
1
1
Laboratoire de Géologie, Ecole normale supérieure, CNRS UMR8538, PSL research university, Paris, France
2
Sorbonne Universités, UPMC Université Paris 06, CNRS UMR 7193, ISTeP, Paris, France
Abstract
The Owen Fracture Zone (OFZ) is the present-day, 800-km-long dextral India Arabia plate boundary,
with conspicuous pull-apart basins at stepover areas and at its terminations. We summarize geological
evidence documenting the age of formation of the OFZ, based on detailed analysis of geophysical and
drilling data in the vicinity of the main pull-apart basins. Although India-Arabia motion started in the
Late Cretaceous, we show that the present-day OFZ is a young structure formed at 2.4 Ma. This last
structural reorganization of the India-Arabia plate boundary is unrelated to any well-documented
kinematic change, leaving questions over its driver.
Keywords: Fracture zone pull apart- horsetail- Indian Ocean

1 – Introduction
Strike-slip plate boundaries display a large variety of geological structures along their strike, especially
in areas where the layout of the displacement zone is discontinuous or curved (Mann, 2007). These step-over
areas favor the formation of releasing or restraining bends, according to the configuration of adjacent strike-slip
fault segments and the local stress field (Sylvester, 1988). Detailed tectonic and stratigraphic investigations have
revealed that strike-slip boundaries experience dramatic episodes of structural reorganization during their
lifetime, marked by the formation of new structures and the abandonment of older ones (ten Brink and Ben-
Avraham, 1989; Wakabayashi, 2007; Brothers et al., 2009; Schattner, 2010; ten Brink and Flores, 2012; Le
Pichon et al., 2001, 2013). Models of structural evolution have proposed that continental strike-slip boundaries
initiate as diffuse, en-_ echelon fault systems and become narrower with increasing maturity (Tchalenko, 1970;
Wesnousky, 2005; Dooley and Schreurs, 2012; Le Pichon et al., 2016). This pattern of structural evolution is
modulated by the layered rheology of the continental lithosphere (Le Pourhiet et al., 2014).
The structural evolution of oceanic strike-slip faults (with seismicity identified along their entire length) has been
investigated only for a few cases, including the MacQuarie Fault (Australia-Pacific boundary; Massel et al.,
2000; Meckel et al., 2005) or the Azores-Gibraltar transform fault (Nubia-Eurasia boundary; Zitellini et al.,
2009; Rosas et al., 2014; Miranda et al., 2014). Here we focus on the oceanic India-Arabia strike-slip plate
boundary, which initiated 90 Ma when India separated from Madagascar (Bernard and Munschy, 2000) and
started its motion toward Eurasia. The India-Arabia plate boundary experienced several episodes of migrations in
response to India-Eurasia or Arabia-Eurasia collision (Rodriguez et al., 2014a,b, 2016). Multibeam mapping of
the current India-Arabia plate boundary (Fig. 1), referred to as the Owen fracture zone (OFZ) in the Arabian Sea,
revealed dextral morphological offsets of the Owen Ridge on the order of 10 12 km (Fournier et al., 2008a,b,
2011)—the Owen Ridge being a series of bathymetric highs uplifted 8.7 Ma ago (Rodriguez et al., 2014a, b,
2018). Considering steady the current right-lateral motion of 3±1 mm yr
-1
(DeMets et al., 2010), these offsets
indicate a recent reorganization of the OFZ, younger than the Late Miocene.
Using multibeam and seismic data, tied to nearby ODP-DSDP sites, we performed detailed structural and
stratigraphic studies to investigate the age of formation of each major structure (mainly pull-apart basins)
observed along the OFZ in order to determine its age of formation. The results show that the present-day
expression of the entire, 800-km-long OFZ formed at 2.4 Ma, from the Aden-Owen-Carlsberg triple junction to
the Makran subduction zone (Fig. 1) and involved the opening of conspicuous pull-apart basins (from south to
north: the Beautemps-Beaupré Basin, Fig. 2; the 20° N Basin, Fig. 3; the Dalrymple Trough, Fig. 4).
2 – THE SEDIMENTARY RECORD OF STRIKE-SLIP TECTONICS ALONG
THE OWEN FRACTURE ZONE
2.1 The Indus Turbiditic Channels
The OFZ crosses the distal Indus turbidite fan, which is fed from the east by the Indus canyon cutting
through the NW Indian margin (von Rad and Tahir, 1997; Rodriguez et al., 2011, 2013, 2014a, b; Bourget et al.,
2013). Turbiditic channels are observed on both sides of the OFZ (Figs. 3 and 4). In terms of relative
chronology, the turbiditic channels observed west of the OFZ (in the Owen Basin) predate its formation and
indicate a period of limited tectonic activity, or a period when sedimentation rates were too high to record
tectonics. East of the OFZ, the turbiditic channels trapped or deviated by strike-slip structures postdate the
formation of the OFZ. Dating the different turbiditic systems provides good age brackets for the formation of the
OFZ. The age of a turbiditic channel is estimated from the age of the first pelagic layer that covers it.
2.2 Fault-Controlled Contourite Drifts
Bottom currents influence the geometry of deep-sea sedimentary deposits and build conspicuous
sedimentary formations referred to as contourite drifts (Rebesco et al., 2014). In the vicinity of the OFZ, several
fault-controlled contourite drifts are observed within the pelagic blanket lying over the turbiditic channels (Figs.
3 and 4). The opening of pull-apart basins along the OFZ induced local perturbations of bottom current. The base
of a fault-controlled drift indicates the minimum age of formation of the fault.

2.3 Angular Unconformities
Vertical motion of the seafloor (uplift or subsidence) related to faults results in major angular
unconformities within the Indus fan, sometimes outlined by conspicuous fanning configurations recording the
growth of the structure. Within the fanning configurations, numerous unconformities reflect the control of sea-
level variations at the 105 years time-scale over the Indus fan sedimentation (Bourget et al., 2013).
3 AGE OF STRUCTURES ALONG THE OWEN FRACTURE ZONE
3.1 The Beautemps-Beaupré Pull-Apart Basin
The Beautemps-Beaupré Basin is a 120-km-long, 50-km-wide rhomboidal pull-apart basin located at
the southern termination of the OFZ (Fig. 2; Fournier et al., 2008a,b). The Beautemps-Beaupré Basin is almost
entirely filled in by Indus turbidites. The basin is bounded to the south by the Beautemps-Beaupré Ridge
(Rodriguez et al., 2018), which corresponds to a tilted section of Indus turbidites (Fig. 2). Numerous angular
unconformities are identified at the edges of the basin (Fig. 2), most of them being related to interruptions of
Indus sedimentation related to sea-level variations (Bourget et al., 2013). The onset of the uplift of the
Beautemps-Beaupré Ridge is recorded by a conspicuous angular unconformity and the base of the fanning
configuration of a sequence of Indus sediments (Fig. 2; Rodriguez et al., 2018). This unconformity can be
tracked within the Beautemps-Beaupré Basin, where it coincides with the onset of lateral variations in thickness
of turbidites, which marks the onset of seafloor subsidence there. Since its uplift above the level of turbidites
deposition, the Beautemps-Beaupré Ridge is blanketed by pelagic sediments that can be correlated with pelagic
sediments on top of the nearby Owen Ridge (Fig. 2), where ODP sites provide stratigraphic constraints
(Discoaster pentaradius; Shipboard Scientific Party, 1989). This unconformity is dated at 2.4 Ma (Rodriguez et
al., 2014b, 2018).
3.2 The 20°N Pull-Apart Basin
The 20° N Basin, named after its latitude, is an asymmetric, 90-km-long, 12-km-wide pullapart basin
(Fig. 3; Fournier et al., 2011). The OFZ constitutes the western flank of the 20° N Basin, while imbricated
systems of arcuate normal faults dissect its eastern flank (Fig. 3). The 20° N Basin is divided into three subbasins
by the transverse faults (Fig. 3). Fossil turbidite channels are identified west of the basin, whereas the currently
active channel is captured on the eastern side of the basin (Rodriguez et al., 2011; Bourget et al., 2013). The
most recent fossil turbidite channel to the west is dated at 3.4 ± 1.2 Ma (Rodriguez et al., 2013), which gives the
maximal age of the opening of the basin (Fig. 3). A fault-controlled contourite drift, with a typical sigmoid
geometry, is also identified on the top of the master fault (Fig. 3). The opening of the basin may have disturbed
the course of the bottom current and triggered the building of the drift. The reflector marking the base of the drift
can be correlated within the pelagic cover as far as the ODP sites located at the top of the Owen Ridge. The age
of this reflector is 2.4 Ma (Rodriguez et al., 2013, 2014b).
3.3 The Dalrymple Trough
The Dalrymple Trough marks the northern termination of the OFZ (Edwards et al., 2000; Ellouz
Zimmermann et al., 2007). The southern segment of the Dalrymple Trough is a 150-km-long, 30-km-wide
horsetail termination basin (Fig. 4), with numerous oblique splays connecting the OFZ (Fournier et al., 2011;
Rodriguez et al., 2014b). The Dalrymple Trough is flanked to the east by the Murray Ridge. Indus turbidite
channels dated at 3.7 ± 1 Ma to the west of the Dalrymple Trough predate its opening (Fig. 4). In contrast to the
20° N and Beautemps-Beaupré basins, the Dalrymple Trough has been isolated from the Indus infill
subsequently to the uplift of the Murray Ridge. On transverse seismic profile (Fig. 4), the core of the Dalrymple
Trough is expressed as a syncline. The last deformed layer can be fairly correlated with the Indus sequence at the
border of the basin (Fig. 4). It coincides with the reflector marking a major angular unconformity in front of the
Makran accretionary wedge (M-unconformity; Gaedicke et al., 2002; Ellouz Zimmermann et al., 2007).
Moreover, this reflector marks the base of a fault-controlled contourite drift close to the OFZ at the entrance of
the trough (Rodriguez et al., 2014b). Here again, this reflector within well-bedded pelagic layers can be
correlated from line to line to the location of the ODP sites. It is also dated at 2.4 Ma. However, the age of the
northern segment of the Dalrymple Trough, connecting the Ornach Fault in Pakistan, remains to be constrained.

4 – DISCUSSION AND PERSPECTIVES
Detailed tectono-stratigraphic studies indicate the present-day configuration of the entire 800-km-long
OFZ formed at 2.4 Ma, expressed by the coeval opening of the Beautemps-Beaupbasin to the south, the 20° N
basin, and the Dalrymple Trough to the north. Considering the 10 12 km-morphological offsets were formed
during the last 2.4 Ma implies a dextral rate of India-Arabia relative motion at ~ 4.2 ± 5 mm yr
-1
. The India-
Arabia boundary is located in this area since at least the Early Miocene and the first stages of seafloor accretion
at the Sheba Ridge ago (Fournier et al., 2010). The India-Arabia plate boundary has accommodated since then
about 80-km of dextral relative motion (Chamot-Rooke and Fournier, 2009). When the OFZ formed at 2.4 Ma,
the India-Arabia boundary was therefore already a mature system. The timing of the formation of the OFZ at 2.4
Ma does not correspond to a clearly identified kinematic change (DeMets et al., 2017), making the geodynamic
driver of its formation unknown. Either the corresponding kinematic change has not been detected so far, or
there is no kinematic change related to the onset of the OFZ. The formation of the OFZ may simply be the last
step of a series of transient adjustments of the India-Arabia plate boundary since the last major kinematic change
identified in the Indian Ocean between 6 and 8 Ma (DeMets and Merkouriev, 2016; DeMets et al., 2017). It is
also possible that the 2.4 Ma episode of intensification of the Indian Monsoon (An et al., 2001) might have
played a role in the evolution of the strike-slip system through its effect on the Indus sedimentation rates
(increase up to 500 m/Ma at 2.4 Ma; Shipboard Scientific Party, 1989).
Acknowledgments
This study is a synthesis of numerous works based on the multibeam and seismic dataset collected during the
AOC, OWEN 1 and 2 surveys in the last decade. All scientists and cruise members (R/V Beautemps-Beaup,
SHOM) involved in these projects are warmly thanked for their help. We thank J. Duarte and T. Minshull for
their detailed comments that helped us to improve this synthesis.
Figure captions
Figure 1 Multibeam bathymetric map of the Owen fracture zone. Inset shows the plate tectonic context in the
northwestern Indian Ocean. (a) and (b) are enlargements of two areas where the lateral offset has been measured
(respectively 10 and 12 km).
Figure 2 (A) Multibeam bathymetric map of the Beautemps-Beaupré Basin (B
3
)[1], (B) North-South seismic
profile across the Beautemps-Beaupré Basin, and (C) its interpretation (in blue, the post 2.4 Ma infill of the
basin, in black the 8.8 Ma discordance that marks the uplift of the Owen ridge).
Figure 3 (A) Multibeam bathymetric map of the 20°N Basin, OFZ: Owen Fracture Zone, SB1, SB2, SB3: sub-
basins, (B) West-East seismic profile across the sub-basin SB3 of the 20°N Basin, and (C) its interpretation (in
blue, the post 2.4 Ma infill of the basin).
Figure 4 (A) Multibeam bathymetric map of the Dalrymple Trough (inset is a bird’s eye view from the
southwest), (B) West-East seismic profile across the southern part of the Dalrymple Trough, and (C) its
interpretation. The pink reflector dated at 2.4 Ma marks the beginning of the opening of the basin. The post 2.4
Ma infill of the basin is shown in blue.
References
An, Z., Kutzbach, J.E., Prell, W.L., Porter, S.C., 2001. Evolution of Asian monsoons and phased uplift of the Himalaya
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formés à l’axe d’un même centre d’expansion ? C. R. Acad. Sci. Paris 330, 777783.
Bourget, J., Zaragosi, S., Rodriguez, M., Fournier, M., Garland, T., Chamot-Rooke, N., 2013. Late quaternary megaturbidites
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"Structural Reorganization of the In..." refers background in this paper

  • ...Considering steady the current right-lateral motion of 3±1 mm yr (DeMets et al., 2010), these offsets indicate a recent reorganization of the OFZ, younger than the Late Miocene....

    [...]


Journal ArticleDOI
Abstract: The importance of strike-slip faulting was recognized near the turn of the century, chiefly from investigations of surficial offsets associated with major earthquakes in New Zealand, Japan, and California. Extrapolation from observed horizontal displacements during single earthquakes to more abstract concepts of long-term, slow accumulation of hundreds of kilometers of horizontal translation over geologic time, however, came almost simultaneously from several parts of the world, but only after much regional geologic mapping and synthesis. Strike-slip faults are classified either as transform faults which cut the lithosphere as plate boundaries, or as transcurrent faults which are confined to the crust. Each class of faults may be subdivided further according to their plate or intraplate tectonic function. A mechanical understanding of strike-slip faults has grown out of laboratory model studies which give a theoretical basis to relate faulting to concepts of pure shear or simple shear. Conjugate sets of strike-slip faults form in pure shear, typically across the strike of a convergent orogenic belt. Fault lengths are generally less than 100 km, and displacements along them are measurable in a few to tens of kilometers. Major strike-slip faults form in regional belts of simple shear, typically parallel to orogenic belts; indeed, recognition of the role strike-slip faults play in ancient orogenic belts is becoming increasingly commonplace as regional mapping becomes more detailed and complete. The lengths and displacements of the great strike-slip faults range in the hundreds of kilometers. The position and orientation of associated folds, local domains of extension and shortening, and related fractures and faults depend on the bending or stepping geometry of the strike-slip fault or fault zone, and thus the degree of convergent or divergent strike-slip. Elongate basins, ranging from sag ponds to rhombochasms, form as result of extension in domains of divergent strike slip such as releasing bends; pull-apart basins evolve between overstepping strike-slip faults. The arrangement of strike-slip faults which bound basins is tulip-shaped in profiles normal to strike. Elongate uplifts, ranging from pressure ridges to long, low hills or small mountain ranges, form as a result of crustal shortening in zones of convergent strike slip; they are bounded by an arrangement of strike-slip faults having the profile of a palm tree. Paleoseismic investigations imply that earthquakes occur more frequently on strike-slip faults than on intraplate normal and reverse faults. Active strike-slip faults also differ from other types of faults in that they evince fault creep, which is largely a surficial phenomenon driven by elastic loading of the crust at seismogenic depths. Creep may be steady state or episodic, pre-seismic, co-seismic, or post-seismic, depending on the constitutive properties of the fault zone and the nature of the static strain field, among a number of other factors which are incompletely understood. Recent studies have identified relations between strike-slip faults and crustal delamination at or near the seismogenic zone, giving a mechanism for regional rotation and translation of crustal slabs and flakes, but how general and widespread are these phenomena, and how the mechanisms operate that drive these detachment tectonics are questions that require additional observations, data, and modeling. Several fundamental problems remain poorly understood, including the nature of formation of en echelon folds and their relation to strike-slip faulting; the effect of mechanical stratigraphy on strike-slip-fault structural styles; the thermal and stress states along transform plate boundaries; and the discrepancy between recent geological and historical fault-slip rates relative to more rapid rates of slip determined from analyses of sea-floor magnetic anomalies. Many of the concepts and problems concerning strike-slip faults are derived from nearly a century of study of the San Andreas fault and have added much information, but solutions to several remaining and new fundamental problems will come when more attention is focused on other, less well studied strike-slip faults.

1,216 citations


Journal ArticleDOI
Abstract: An examination is made of the formation and development of shear zone structures on (1) the microscopic scale in the shear box test, (2) an intermediate scale in the Riedel experiment, and (3) the regional scale in the earthquake fault. On the basis of the resistance to shear, three structural stages are chosen for detailed study: the peak structure occurring at peak shearing resistance, the post-peak structure occurring after peak shearing resistance, and the residual structure occurring at residual shearing resistance. Most of the similarities in structure between the different scales at each of these stages are interpreted in terms of the mechanical properties of the material, the Coulomb failure criterion, and the kinematic restraints inherent in the type of deformation. Other similarities which are not as yet understood are described and suggested as topics for future research.

969 citations


Journal ArticleDOI
Abstract: The contourite paradigm was conceived a few decades ago, yet there remains a need to establish a sound connection between contourite deposits, basin evolution and oceanographic processes. Significant recent advances have been enabled by various factors, including the establishment of two IGCP projects and the realisation of several IODP expeditions. Contourites were first described in the Northern and Southern Atlantic Ocean, and since then, have been discovered in every major ocean basin and even in lakes. The 120 major contourite areas presently known are associated to myriad oceanographic processes in surface, intermediate and deep-water masses. The increasing recognition of these deposits is influencing palaeoclimatology & palaeoceanography, slope-stability/geological hazard assessment, and hydrocarbon exploration. Nevertheless, there is a pressing need for a better understanding of the sedimentological and oceanographic processes governing contourites, which involve dense bottom currents, tides, eddies, deep-sea storms, internal waves and tsunamis. Furthermore, in light of the latest knowledge on oceanographic processes and other governing factors (e.g. sediment supply and sea-level), existing facies models must now be revised. Persistent oceanographic processes significantly affect the seafloor, resulting in large-scale depositional and erosional features. Various classifications have been proposed to subdivide a continuous spectrum of partly overlapping features. Although much progress has been made in the large-scale, geophysically based recognition of these deposits, there remains a lack of unambiguous and commonly accepted diagnostic criteria for deciphering the small-scaled contourite facies and for distinguishing them from turbidite ones. Similarly, the study of sandy deposits generated or affected by bottom currents, which is still in its infancy, offers great research potential: these deposits might prove invaluable as future reservoir targets. Expectations for the forthcoming analysis of data from the IODP Expedition 339 are high, as this work promises to tackle much of the aforementioned lack of knowledge. In the near future, geologists, oceanographers and benthic biologists will have to work in concert to achieve synergy in contourite research to demonstrate the importance of bottom currents in continental margin sedimentation and evolution.

455 citations


"Structural Reorganization of the In..." refers background in this paper

  • ...Bottom currents influence the geometry of deep-sea sedimentary deposits and build conspicuous sedimentary formations referred to as contourite drifts (Rebesco et al., 2014)....

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Frequently Asked Questions (2)
Q1. What are the contributions in "Structural reorganization of the india-arabia strike-slip plate boundary (owen fracture zone; nw indian ocean) 2.4 million years ago" ?

Although India-Arabia motion started in the Late Cretaceous, the authors show that the present-day OFZ is a young structure formed at 2. 

Contourites and associated sediments controlled by deep-water circulation processes: state of the art and future considerations.