The sedimentary markers of the Messinian salinity crisis and their relation with salt tectonics on the Provençal margin (western Mediterranean): results from the “MAURESC” cruise

2011 ◽  
Vol 182 (2) ◽  
pp. 181-196 ◽  
Author(s):  
Edda Marlène Obone-Zue-Obame ◽  
Virginie Gaullier ◽  
Françoise Sage ◽  
Agnès Maillard ◽  
Johanna Lofi ◽  
...  
Keyword(s):  
Sedimentary Cover ◽  
Close Relation ◽  
Western Mediterranean ◽  
Seismic Facies ◽  
Normal Faults ◽  
Salt Tectonics ◽  
Messinian Salinity Crisis ◽  
Deep Basin ◽  
Seismic Reflection Data ◽  
Reflection Data

Abstract The Messinian salinity crisis (MSC) is characterized by gigantic erosion that remodels the margins while a thick, essentially evaporitic and detrital, sedimentary sequence forms in the deep basins. Based on recent (MAURESC, 2003) and earlier (MESEA 1, 1990; MAGIRAA, 1996; GEOBREST, 2002) seismic reflection data, this work brings to light the record of the MSC on the Provençal margin, which has until now been rarely explored from this perspective. Beyond its strictly regional interest, this study fits into a larger synthesis of MSC seismic markers in the Mediterranean and Black Sea marine domain [Lofi et al., 2011] and employs the new nomenclature established on this occasion. The results obtained reveal a Messinian detrital body (CU unit) of 625 metres maximum thickness at the foot of the margin, accumulating at the mouths of the principal canyons. Its form, facies and extension assimilate it to clastic fans, fed by subaerial erosion linked to the MSC. The relative geometry of CU and the Messinian units MU and UU deposited in the deep basin give indications to their chronostratigraphic relations. The deposition of the CU unit is posterior to the basal part of the mobile unit consisting of halite (MU), but contemporary to its top. These results agree with the recent scenarii, which propose that the precipitation of MU in the basin began early, during the lowering of the sea level, and ended at a low level during the MSC [Blanc, 2000; Martin et al., 2001; Sage et al., 2005; Ryan, 2009]. The UU unit surmounts MU and is subdivided into two sub-units with perceptibly different seismic facies : UU1 at the base and UU2 at the summit. UU1 could correspond to a unit containing more halite and/or more clastic material than UU2. The UU1 sub-unit could be partially contemporary to the CU unit. Concerning salt tectonics and its markers, three structural provinces have been evidenced in the sector of study, respectively : an upslope domain in extension (normal faults), an intermediary domain in translation (tabular MU) and a downslope domain in contraction (salt diapirs). These domains are directly linked to the gravity spreading and/or gliding of the brittle sedimentary cover formed by the CU, UU and Plio-Quatenary units and of the mobile level, MU. In the study area, a close relation between the distribution and thickness of CU and salt tectonics has additionally been evidenced at the mouths of the large Messinian canyons, being best expressed where CU is thick.

Salt morphologies and crustal segmentation relationship: new insights from Western Mediterranean Sea and other salt passive margins 

2021 ◽  
Author(s):  
Massimo Bellucci ◽  
Daniel Aslanian ◽  
Maryline Moulin ◽  
Marina Rabineau ◽  
Estelle Leroux ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Western Mediterranean ◽  
Normal Faults ◽  
Salt Tectonics ◽  
Deep Basin ◽  
Thermal Anomalies ◽  
Passive Margins ◽  
Western Mediterranean Sea ◽  
Initial Salt ◽  
Geometrical Variation

<p>Salt tectonics at salt-bearing margins is often interpreted as the combination of gravity spreading and gravity gliding, mainly driven by differential sedimentary loading and margin tilting, respectively. Nevertheless, in the Western Mediterranean Sea, the classical salt tectonics models are incoherent with its morpho-structural setting: the Messinian salt was deposited in a closed system, formed several Ma before the deposition, horizontally in the entire deep basins, above a homogenous multi-kilometre pre-Messinian thickness. The subsidence is purely vertical in the deep basin, implying a regional constant initial salt thickness, the post-salt overburden is homogenous and the distal salt deformation occurred before the mid-lower slope normal faults activation. Instead, the compilation of MCS and wide-angle seismic data highlighted a clear coincidence between crustal segmentation and salt morphology domains. The geometrical variation of salt structures seems to be related to the underlying crustal nature segmentation. Regional thermal anomalies and/or fluid escapes, associated with the exhumation phase, or the mantle heat segmentation, could therefore play a role in adding a further component on the already known salt tectonics mechanisms. The compilation of crustal segmentation and salt morphologies in different salt-bearing margins, such as the Santos, Angolan, Gulf of Mexico and Morocco-Nova Scotia margins, seems to depict the same coincidence. In view of what is observed in Western Mediterranean Sea, the heat segmentation influence in the passive margins should not be overlooked and deserves further investigation.</p>

Image improvement of Late Miocene (Messinian) to Plio-Quaternary units in the Algero-Balearic basin

2020 ◽  
Author(s):  
Simon Blondel ◽  
Fadl Raad ◽  
Angelo Camerlenghi ◽  
Johanna Lofi ◽  
Anna Del Ben
Keyword(s):  
Seismic Data ◽  
Early Stage ◽  
Complex Salt ◽  
Western Mediterranean ◽  
Seismic Facies ◽  
Messinian Salinity Crisis ◽  
Transform Fault ◽  
The South ◽  
Seismic Reflection Data ◽  
Multichannel Seismic Data

<p>This study intends to contribute to the understanding of the Mediterranean Salt Giant in the Western Mediterranean, formed about 6 Ma ago during the Messinian Salinity Crisis. It provides reprocessed multichannel seismic reflection data that aim at improving our knowledge of the stratigraphy in the Algero-Balearic deepwater basin and its continental margins, in the absence of lithological information from wells.</p><p>We investigate the seismic expression of the Messinian salinity crisis from the south-east of the Balearic promontory to the central Algero-Balearic abyssal basin and the salt tectonic processes associated to these facies. Here the segmentation of salt structures has been previously described using shallow chirp sonar data, low-resolution vintage multichannel seismic data and high-resolution multi-channel seismic data post-stack migrated with a constant velocity field. The structure of the northern Algero-Balearic basin is controlled by two abrupt fault scarps oriented SW–NE (mainly the Emile Baudot Escarpment transform fault) and WSW-ENE (mainly the Mazarron Escarpment transform fault) emplaced during the basin extension, and later intruded by steep and narrow volcanic ridges of Pleistocene age. It is a good analogue to early stage salt tectonic for older and more complex salt giants in the North Sea or the Gulf of Mexico.</p><p>We reprocessed 2D Kirchhoff PSTM multichannel seismic data acquired by the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale – OGS (SBALDEEP Cruise of 2005 and SALTFLU cruise of 2012; the latter within a Eurofleet cruise) spanning the South-East continental margin of the Balearic islands and the Algero-Balearic basin. The reprocessing was designed for improving the continuity of the reflectors by applying Kirchhoff PSTM using a detailed velocity model, while preserving amplitude information. The objectives are to better apprehend the structural complexity of the area and to retrieve the amplitude variation within the Messinian units, in an attempt to derive the composition of the salt and the pressure regime.</p><p>We present preliminary results where we delineate four different domains based on i) the seismic facies, ii) the amount of salt deformation, iii) the thickness of the overburden and iv) the pre-salt configuration. We try to assess the presence of the Messinian trilogy in the south-eastern continental slope. We attempt to reconstitute the paleo-depositionnal environment of the various depositional units, and the effect of crustal structures and salt tectonic gravity spreading and gliding on their syn to post-depositional evolution. Finally, we search for evidence of fluid circulation within the Messinian and the Plio-Quaternary deposits over the study area.</p>

The syn-rift sedimentary cover of the North Biscay Margin (bay of Biscay): from new reflection seismic data

2002 ◽  
Vol 173 (6) ◽  
pp. 515-522 ◽  
Author(s):  
Isabelle Thinon ◽  
Jean-Pierre Réhault ◽  
Luis Fidalgo-González
Keyword(s):  
Seismic Data ◽  
Sedimentary Basin ◽  
Sedimentary Cover ◽  
Seismic Facies ◽  
Bay Of Biscay ◽  
Seismic Reflection Data ◽  
Reflection Seismic ◽  
The North ◽  
Reflection Data ◽  
Lower Aptian

Abstract The Armorican Basin is a deep sedimentary basin lying at the footside of the North Bay of Biscay. From previous scattered inadequate data, the age and nature of this basin, oceanic domain or deep part of the Armorican margin itself were largely speculated. From this new seismo-stratigraphic study based on a dense seismic cover, the sedimentation within the Armorican Basin is beginning in the Aptian times, during the last tectonic rifting episode of the margin. The first sediments formation identified as the « 3B layer » is characterised on the profiles by a chaotic and transparent seismic facies and was emplaced by slumping process when the margin collapsed, at the final rifting phase, just before the oceanic accretion. The new seismic reflection data give also some informations on the polyphased evolution of the North Biscay Margin during the rifting period. Two main events occurred during the Lower Cretaceous times (the first one is pre-Berriasian, the second is Aptian), separated by a quiet tectonic period including the Upper Berriasian and Lower Aptian times. The first event is responsible of the margin tectonic structuration in some blocks, the second of collapsing and the emplacement of the allochthonous sediments (3B layer) in the Armorican Basin.

scholarly journals Mantle-derived helium released through the Japan trench bend-faults

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin-Oh Park ◽  
Naoto Takahata ◽  
Ehsan Jamali Hondori ◽  
Asuka Yamaguchi ◽  
Takanori Kagoshima ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Large Scale ◽  
Japan Trench ◽  
Helium Isotope ◽  
Normal Faults ◽  
Circulation System ◽  
Deep Penetration ◽  
Oceanic Plate ◽  
Seismic Reflection Data ◽  
Reflection Data

AbstractPlate bending-related normal faults (i.e. bend-faults) develop at the outer trench-slope of the oceanic plate incoming into the subduction zone. Numerous geophysical studies and numerical simulations suggest that bend-faults play a key role by providing pathways for seawater to flow into the oceanic crust and the upper mantle, thereby promoting hydration of the oceanic plate. However, deep penetration of seawater along bend-faults remains controversial because fluids that have percolated down into the mantle are difficult to detect. This report presents anomalously high helium isotope (3He/4He) ratios in sediment pore water and seismic reflection data which suggest fluid infiltration into the upper mantle and subsequent outflow through bend-faults across the outer slope of the Japan trench. The 3He/4He and 4He/20Ne ratios at sites near-trench bend-faults, which are close to the isotopic ratios of bottom seawater, are almost constant with depth, supporting local seawater inflow. Our findings provide the first reported evidence for a potentially large-scale active hydrothermal circulation system through bend-faults across the Moho (crust-mantle boundary) in and out of the oceanic lithospheric mantle.

scholarly journals Seismic reflection data reveal the 3D structure of the newly discovered Exmouth Dyke Swarm, offshore NW Australia

2020 ◽  
Author(s):  
Craig Magee ◽  
Christopher A.-L. Jackson
Keyword(s):  
Seismic Reflection ◽  
Surface Deformation ◽  
3D Structure ◽  
Sedimentary Basins ◽  
Dyke Swarm ◽  
Normal Faults ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Dyke Swarms ◽  
Nw Australia

Abstract. Dyke swarms are common on Earth and other planetary bodies, comprising arrays of dykes that can extend for 10's to 1000's of kilometres. The vast extent of such dyke swarms, and their rapid emplacement, means they can significantly influence a variety of planetary processes, including continental break-up, crustal extension, resource accumulation, and volcanism. Determining the mechanisms driving dyke swarm emplacement is thus critical to a range of Earth Science disciplines. However, unravelling dyke swarm emplacement mechanics relies on constraining their 3D structure, which is extremely difficult given we typically cannot access their subsurface geometry at a sufficiently high enough resolution. Here we use high-quality seismic reflection data to identify and examine the 3D geometry of the newly discovered Exmouth Dyke Swarm, and associated structures (i.e. dyke-induced normal faults and pit craters), in unprecedented detail. The latest Jurassic dyke swarm is located on the Gascoyne Margin offshore NW Australia and contains numerous dykes that are > 170 km long, potentially > 500 km long. The mapped dykes are distributed radially across a 39° arc centred on the Cuvier Margin; we infer this focal area marks the source of the dyke swarm, which was likely a mantle plume. We demonstrate seismic reflection data provides unique opportunities to map and quantify dyke swarms in 3D in sedimentary basins, which can allow us to: (i) recognise dyke swarms across continental margins worldwide and incorporate them into models of basin evolution and fluid flow; (ii) test previous models and hypotheses concerning the 3D structure of dyke swarms; (iii) reveal how dyke-induced normal faults and pit craters relate to dyking; and (iv) unravel how dyking translates into surface deformation.

scholarly journals Seismic reflection data reveal the 3D structure of the newly discovered Exmouth Dyke Swarm, offshore NW Australia

Solid Earth ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 579-606 ◽  
Author(s):  
Craig Magee ◽  
Christopher Aiden-Lee Jackson
Keyword(s):  
Seismic Reflection ◽  
Surface Deformation ◽  
3D Structure ◽  
Dyke Swarm ◽  
Normal Faults ◽  
Borehole Data ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Dyke Swarms ◽  
Nw Australia

Abstract. Dyke swarms are common on Earth and other planetary bodies, comprising arrays of dykes that can extend laterally for tens to thousands of kilometres. The vast extent of such dyke swarms, and their presumed rapid emplacement, means they can significantly influence a variety of planetary processes, including continental break-up, crustal extension, resource accumulation, and volcanism. Determining the mechanisms driving dyke swarm emplacement is thus critical to a range of Earth Science disciplines. However, unravelling dyke swarm emplacement mechanics relies on constraining their 3D structure, which is difficult given we typically cannot access their subsurface geometry at a sufficiently high enough resolution. Here we use high-quality seismic reflection data to identify and examine the 3D geometry of the newly discovered Exmouth Dyke Swarm, and associated structures (i.e. dyke-induced normal faults and pit craters). Dykes are expressed in our seismic reflection data as ∼335–68 m wide, vertical zones of disruption (VZD), in which stratal reflections are dimmed and/or deflected from sub-horizontal. Borehole data reveal one ∼130 m wide VZD corresponds to an ∼18 m thick, mafic dyke, highlighting that the true geometry of the inferred dykes may not be fully captured by their seismic expression. The Late Jurassic dyke swarm is located on the Gascoyne Margin, offshore NW Australia, and contains numerous dykes that extend laterally for > 170 km, potentially up to > 500 km, with spacings typically < 10 km. Although limitations in data quality and resolution restrict mapping of the dykes at depth, our data show that they likely have heights of at least 3.5 km. The mapped dykes are distributed radially across a ∼39∘ wide arc centred on the Cuvier Margin; we infer that this focal area marks the source of the dyke swarm. We demonstrate that seismic reflection data provide unique opportunities to map and quantify dyke swarms in 3D. Because of this, we can now (i) recognise dyke swarms across continental margins worldwide and incorporate them into models of basin evolution and fluid flow, (ii) test previous models and hypotheses concerning the 3D structure of dyke swarms, (iii) reveal how dyke-induced normal faults and pit craters relate to dyking, and (iv) unravel how dyking translates into surface deformation.

scholarly journals Hydraulic fracturing in thick shale basins: problems in identifying faults in the Bowland and Weald Basins, UK

2016 ◽  
Author(s):  
David K. Smythe
Keyword(s):  
Hydraulic Fracturing ◽  
Seismic Reflection ◽  
Upper Jurassic ◽  
Normal Faults ◽  
Regulatory Regime ◽  
Seismic Line ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Unconventional Resource ◽  
The Uk

Abstract. North American shale basins differ from their European counterparts in that the latter are one to two orders of magnitude smaller in area, but correspondingly thicker, and are cut or bounded by normal faults penetrating from the shale to the surface. There is thus an inherent risk of groundwater resource contamination via these faults during or after unconventional resource appraisal and development. US shale exploration experience cannot simply be transferred to the UK. The Bowland Basin, with 1900 m of Lower Carboniferous shale, is in the vanguard of UK shale gas development. A vertical appraisal well to test the shale by hydraulic fracturing (fracking), the first such in the UK, triggered earthquakes. Re-interpretation of the 3D seismic reflection data, and independently the well casing deformation data, both show that the well was drilled through the earthquake fault, and did not avoid it, as concluded by the exploration operator. Faulting in this thick shale is evidently difficult to recognise. The Weald Basin is a shallower Upper Jurassic unconventional oil play with stratigraphic similarities to the Bakken play of the Williston Basin, USA. Two Weald licensees have drilled, or have applied to drill, horizontal appraisal wells based on inadequate 2D seismic reflection data coverage. I show, using the data from the one horizontal well drilled to date, that one operator failed identify two small but significant through-going normal faults. The other operator portrayed a seismic line as an example of fault-free structure, but faulting had been smeared out by reprocessing. The case histories presented show that: (1) UK shale exploration to date is characterised by a low degree of technical competence, and (2) regulation, which is divided between four separate authorities, is not up to the task. If UK shale is to be exploited safely: (1) more sophisticated seismic imaging methods need to be developed and applied to both basins, to identify faults in shale with throws as small as 4–5 m, and (2) the current lax and inadequate regulatory regime must be overhauled, unified, and tightened up.

Basement-involved inversion at the Appalachian structural front, western Newfoundland: an interpretation of seismic reflection data with implications for petroleum prospectivity

2004 ◽  
Vol 52 (3) ◽  
pp. 215-233 ◽  
Author(s):  
Glen S. Stockmal ◽  
Art Slingsby ◽  
John W.F. Waldron
Keyword(s):  
Seismic Reflection ◽  
Hanging Wall ◽  
Normal Fault ◽  
Hydrocarbon Exploration ◽  
Normal Faults ◽  
Apparent Magnitude ◽  
Seismic Reflection Data ◽  
The Public ◽  
Reflection Data ◽  
New Interpretation

Abstract Recent hydrocarbon exploration in western Newfoundland has resulted in six new wells in the Port au Port Peninsula area. Port au Port No.1, drilled in 1994/95, penetrated the Cambro-Ordovician platform and underlying Grenville basement in the hanging wall of the southeast-dipping Round Head Thrust, terminated in the platform succession in the footwall of this basement-involved inversion structure, and discovered the Garden Hill petroleum pool. The most recent well, Shoal Point K-39, was drilled in 1999 to test a model in which the Round Head Thrust loses reverse displacement to the northeast, eventually becoming a normal fault. This model hinged on an interpretation of a seismic reflection survey acquired in 1996 in Port au Port Bay. This survey is now in the public domain. In our interpretation of these data, the Round Head Thrust is associated with another basement-involved feature, the northwest-dipping Piccadilly Bay Fault, which is mapped on Port au Port Peninsula. Active as normal faults in the Taconian foreland, both these faults were later inverted during Acadian orogenesis. The present reverse offset on the Piccadilly Bay Fault was previously interpreted as normal offset on the southeast-dipping Round Head Thrust. Our new interpretation is consistent with mapping on Port au Port Peninsula and north of Stephenville, where all basement-involved faults are inverted and display reverse senses of motion. It also explains spatially restricted, enigmatic reflections adjacent to the faults as carbonate conglomerates of the Cape Cormorant Formation or Daniel’s Harbour Member, units associated with inverted thick-skinned faults. The K-39 well, which targeted the footwall of the Round Head Thrust, actually penetrated the hanging wall of the Piccadilly Bay Fault. This distinction is important because the reservoir model invoked for this play involved preferential karstification and subsequent dolomitization in the footwalls of inverted thick-skinned faults. The apparent magnitude of structural inversion across the Piccadilly Bay Fault suggests other possible structural plays to the northeast of K-39.

Structural Relations and Earthquake Hazards of the Crittenden County Fault Zone, Northeastern Arkansas

1992 ◽  
Vol 63 (3) ◽  
pp. 249-262 ◽  
Author(s):  
Anthony J. Crone
Keyword(s):  
Fault Zone ◽  
Crystalline Basement ◽  
Normal Faults ◽  
Reverse Fault ◽  
Seismic Zone ◽  
Earthquake Hazards ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
Magnetic Basement ◽  
Structural Relations

Abstract A preliminary interpretation of about 135 km of seismic-reflection data provides new information on the structural relations between the the Crittenden County fault zone and the subjacent rift-bounding faults along the southeastern margin of the Reelfoot rift in the New Madrid seismic zone. On the reflection data, the rift boundary is marked by a 4- to 8-km-wide zone of incoherent reflected energy and disrupted reflectors in the lower part of the well-stratified, lower Paleozoic sedimentary rocks and in the underlying Precambrian crystalline basement. In places, the zone of disrupted reflectors extends into the upper part of the Paleozoic rocks, and, on some lines, disrupted reflectors and distinct faults are present in the Upper Cretaceous and Tertiary rocks of the Mississippi Embayment. The Crittenden County fault zone is interpreted as a northwest-dipping, high-angle reverse fault with an up-to-the-northwest throw, which is opposite to the net structural relief in the subjacent graben. The fault zone is at least 32 km long and coincides with the rift margin in southwestern Crittenden County, but to the northeast, it diverges away from the aeromagnetically defined margin of the rift by almost 4 km. Most faults in the Crittenden County fault zone are apparently ancient rift-bounding normal faults that were reactivated with a significant amount of reverse slip during the Mesozoic and Cenozoic. On the basis of its apparent connection with the rift-bounding faults, the evidence of its long history of recurrent movement, and its orientation with respect to the modern stress field, the Crittenden County fault zone might be considered to potentially generate major earthquakes. In contrast, the possibility that the Crittenden County fault zone could be a bending-moment fault argues against it being extremely hazardous. Precambrian crystalline basement interpreted on the profiles is commonly deeper than magnetic basement by as much as 2.5 km. This discrepancy between shallow magnetic basement and deeper crystalline basement could be explained by the presence of igneous intrusions in the Paleozoic strata immediately above Precambrian basement.

Sign in / Sign up

Export Citation Format

Share Document