Orogenesis: a New Definition

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In GSST (Global Strike-Slip Tectonic) approach, orogenesis defines the main space shortening process of transpressional shear zones, involving the coalescence of various, different scale and hierarchy crustal fragments, i.e. piko-, nano- and microplates. Initial push-up ranges or (proto-orogenes) evolve into orogens by the means of horizontal and vertical duplexing mechanisms.

Consumption of Oceanic Plates – Review of the Subduction Concept

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Fig24MarianaSubduction first of all it means recycling, i.e. recycling of crustal fragments into the asthenosphere. When oceanic crustal fragments are rising above baselevel, we speak about obduction processes, whilst in case crustal fragments are indeed melted into the asthenosphere we may speak about subduction processes.

According to the GSST theory, kinematic plate fragments are in constant motion, showing certain relative plate velocity contrasts. Under constraints of the Coriolis force, hence, due to their accumulated momentum, microplates tend to rather develop transpressional orogenic build-ups on their longer edges than forming subduction zones during their constant eastward drift. As a consequence, oceanic plate fragments instead of being recycled are rather preserved, being obducted into orogenic complexes, where they are forming suture zones. In other words, the presence of ophiolites in orogenic complexes is the proof of obduction processes, and only indirectly can be inferred the presence of subduction zones from mass balance considerations. Hence, it is not surprising that the peri-Tethys area is full of obducted ophiolite units; starting with the Vardar, Transylvanides, Dinarides, dozens of Asian (e.g. Anatolian) obducted ophiolites in the geological record are all product of transpressional strike-slip tectonics.

Because of global kinematic constraints, subduction may happen only perpendicularly to the principal plate drifting vector or more frequently, as a function of the principal drifting vector of kinematic chains. This means, that real subduction may only form roughly in N-S direction. Basically there are only two such kind of convergent plate boundary lineaments on the Earth, where plate recycling could happen: 1) at the western Pacific plate margin, 2) and at the eastern Pacific plate margin.

In section 3, we have already reviewed the main geological, geophysical, geodetic observations made regarding the evolution of the Japan Island. All these data are proving the significance of shear deformation in northeast Japan, where the intensity of fault activities is very pronounced, earthquake epicenters indicating the presence of E-W directed fault planes. Clustering of earthquake epicenters in stress nodes is generally present all along the Western Pacific subduction zones, from the Sumatra Arc to the Philippine subduction zone. Pacific plate velocity measurements might change with time as new GPS stations will be installed in the oceanic domain, and if the motion of smaller crustal units is also going to be integrated. The origin of the Mariana Trench and the Bonin Ridge is linked to the same strike-slip displacement, which was made along the irregular Hawaii North Mp/ Bonin Nanoplate boundary, in S to N direction. This irregular plate boundary in turn is the result of another plate velocity contrast, which is characterizing the Bonin Np–Hawaii North Mp and the North Philippine–Hawaii South Mp kinematic chains.

Therefore, structural features of the Japan Island and the whole southeastern Asia island-belt, suggest that instead of real subduction we are facing various transpressional space management processes, best described with the term of plate-overriding, i.e a mix of obduction, lateral escape, plate buckling mechanisms.

From a kinematic perspective, real subduction, where recycling of crustal fragments occurs it could only happen in the western margin of the American continents. Here, all the kinematic prerequisites of subduction are present: 1) the motor of subduction is present, and it can be identified in the Coriolis force, which is transferred and exploited by the momentum of plates, 2) there is an obvious density, hence a momentum contrast, between the oceanic and continental crustal fragments.

Momentum contrasts between plate fragments can play a significant role in the initiation of both oceanic spreading and subduction processes, in case the Earth suffers angular acceleration. Whether the angular acceleration of planets is a common planetary phenomenon or not, it is out of our knowledge, but certainly accidental larger meteoric impacts may affect the spinning velocity of the Earth.

Published in: Kovács, J.Sz., 2015 (in press), Elements of Global Strike-Slip Tectonics: a Quasi-Neotectonic Analysis, Journal of Global Strike-Slip Tectonics, v1., Szekler Academic Press, Sfintu Gheorghe.

The ‘Walled Basin’ Model of the Transylvanian Basin: Geodynamic Implications

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In Central Asia several ‘walled basins’  (Carroll et al., 2010) exist which are recording thick lacustrine to alluvial deposits through geological times, and are actually showcasing the various types of strike-slip basins, in nature. Sedimentation is starting in some basins, like in the Junggar Basin, already in the Late Permian (Hendrix et al., 1992), in others during the Mesozoic (Fig. 28, 29). In western China strike-slip basins are contractional in origin, while in eastern China basins are younger pull-apart basins; the interior of these basins practically had stayed undeformed, only basin margins evolved into high to very high orogenic build-ups (Carroll et al., 2010). According to Carroll, many terms have been used to describe these basins ‘broken foreland’, ‘cornered foreland’,  ‘Chinese-type basin’, ‘collisional successor basin’.

If we recall, such walled basins can be seen in the Mediterranean area, as well, like in the case of the South Adriatic basin.

The Neogene Transylvanian Basin it is also a good candidate, in terms of basin mechanism, quality of sedimentary infill. It shows  very similar ‘walled basin’ margin character in all directions, a lacustrine-alluvial sedimentary infill, and it was called for a long time as a back-arc basin, assuming the Roydenian tectonic model. Herein, we propose to adopt the ‘walled basin’ model for the Neogene Transylvanian basin because many of the characteristics traditionally considered as mysterious  are getting a robust explanation, like 1) basin geometry, 2) sediment infill, 3) subsidence rates, 4) thickening of the lithosphere, 5) low heat flux, 6) uplift mechanism of the Southern Carpathians, 7) Peri-Carpathian basin geometry and many others that are going to be presented  in a separate paper.

We need to note, that the geodynamic evolution of the Southern Carpathians was generally neglected from the geodynamic models, because did not really fit into the back-arc model of the Pannonian-basin.  Secondly, it is obvious that the highest mountains of the Earth should share something in common regarding their origin, and geodynamic history. The Tian Shan Mts. are showing peaks of 7000m, the Caucasus has peaks above 5000m, the Atlas is rising above 4000m, the Alps have peaks of 3000m, and finally the highest peaks of Romania are found in the Southern Carpathians (above 2500m). All these very  high and relatively narrow mountain ranges are bounded by steep transpressional fault systems, just as in the case of the Southern Carpathian Mts.

Published in: Kovács, J.Sz., 2015 (in press), Elements of Global Strike-Slip Tectonics: a Quasi-Neotectonic Analysis, Journal of Global Strike-Slip Tectonics, v1., Szekler Academic Press, Sfintu Gheorghe.

Consistency Check I: The Mediterranean Area and the Vøring Basin

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Fig15Herodotus

Strike-slip fault system of the South Mediterranean area (Matruh and Herodotus Basin), extracted from composite seismic profile published by Tari et al., 2012. Two different fault systems can be identified; the primary one is the regional strike-slip system. The secondary deformation events, materialized as listric faults and thrustings, are also triggered by strike-slip tectonics: 1) gravitational sliding in the transtensional stress field sector, 2) and contractional vertical and lateral duplexing in the transpressional stress field sector.

The thinning of the Mediterranean crust below the Sirte Basin and the Ionian Sea  has been evidenced recently by gravity inversion (Cowie and Kusznir, 2012). Cowie and Kusznir have also noted that the nature of the crust could be either oceanic or thinned continental. On their second profile, which transects the Herodotus Basin the transform nature of the basin margin i.e the sudden increase of crustal thickness is more prominent, as a consequence most probably the masterfault of basin opening was localized on the southern basin margin of the Mediterranean Sea.

In our interpretation, gravity profile from Fig.20 is showing additional arguments for the transtensional origin of the Mediterranean crust. Here, contrary to the southern margin, crustal thinning was enabled by overstepping strike-slip faults. The crustal thinning mechanism cannot be understood solely from the published profiles, but certainly must be sought in those of transtensional strike-slip basins.

Southern transform margin of the Mediterranean Basin (Matruh-Herodotus Basin)

An ENE-ESE opening of the East Mediterranean area related to a transform margin was documented by several authors (Longacre et al., 2007; Walley, 1998, 2001) in (Tari et al., 2012), and indeed strike-slip tectonics suggested by gravity profiles (Cowie and Kusznir, 2012) is supported by seismic profiles as well. Reinterpreting a composite profile across the Matruh-Herodotus Basin margin, we have concluded that  it is likely, that an important amount of the structural traps identified in the Matruh Basin were generated by the local Neogene transpressional stress regime. Actually, down-dip contractional horses interpreted by (Tari et al., 2012) might originate partly in strike-slip deformation than solely in gravitational sliding on a Cretaceous shale detachment, as indicated by the presence of numerous antithetic faults. The NNE-SSW Matruh Canyon itself, described by Tari as an aborted syn-rift basin, it is overlaying a Jurassic(?)-Cretaceous transtensional shear zone, most probably initiated as a plate-scale tension fracture, which is depicting the whole coeval North African stress regimes. Interestingly, the main strike of the basin is parallel with those of the NOSA zone in Tunis, which also belongs to the Sirte Microplate in our plate tectonic subdivision.

Eratosthenes Seamount

The Eratosthenes Sea Mount of the Levantine basin was reimaged recently with modern processing techniques (Peace et al., 2012). Around the Eratosthenes seamount, two sets of strike-slip faults can be differentiated highlighting the transpressional origin of the seamount. This crustal fragment initially it constituted a footwall segment of the Levantine Basin, related to a major transtensional fault, which later got inverted  with the evolution of the local stress-regime along the main displacement zone. Stratigraphy given in Fig. 22 is very uncertain; layering is rather reflecting seismic packages than established stratigraphic units.

Northern margin of the Mediterranean Basin

The Corinth Trough (Fig. 26) can be described as a 1-2 Ma old, ~100X30km high-strain band, which shows 5-15mm/year N-S extension (Bell et al., 2009), and segmented, overstepping boundary faults in plain view. Bell is referring to three prevailing theories which are used to explain basin extension: 1) back-arc extension related to the Hellenic Trench, 2) westward propagation of the North Anatolian fault (Dewey and Şengör, 1979), 3) gravitational collapse of the Hellenide orogeny lithosphere (Jolivet, 2001).

In the frame of GSST, the Corinth Trough is interpreted as an internal shear zone of the South Anatolian Nanoplate, which has developed internally an overstepping fault network in the principal displacement zone (PDZ), instead of a continuous masterfault. Given the significant space created in the releasing bend of the PDZ, gravitational collapse proposed by Jolivet (2001) is regarded as a complimentary effect of the regional strike-slip tectonic deformation.

The Vøring Basin, offshore Norway

Within the Vøring Basin, several compressional (Cenomanian-Turonian, Maastrichtian-Paleocene, Middle Miocene) and extensional collapse phases (Paleozoic, Late Jurassic, Early Cretaceous hyperextension, Late Paleocene, Early Eocene) have been documented (Lundin et al., 2013). Overviewing Lundin’s data, we have noted that the ‘early’ (Permian–Jurassic) tension fractures in many places have evolved into overstepping strike-slip faults and several isolated subbasins formed. It should be also noted, that main (SSW-NNE trending) sedimentary trenches, are cut by  further W-E striking strike-slip systems in the continuation of mid-oceanic transforms, giving birth to complex structural patterns. During  periods of inversion, i.e. when structural blocks have arrived into restraining phase, some fault blocks evolved into push-up ranges, like the Vema Dome (Fig. 24), which has been formed in the Middle Miocene.

Published in: Kovács, J.Sz., 2015 (in press), Elements of Global Strike-Slip Tectonics: a Quasi-Neotectonic Analysis, Journal of Global Strike-Slip Tectonics, v1., Szekler Academic Press, Sfintu Gheorghe.

Definition of Micro-, Nano-, Pikoplates and Kinematic Chains

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Marquesas Mp-Ganges Mp kinematic chain is found south of the Cretaceous Panglobal Fracture Zone, and incorporates microplates of the Pacific Ocean, South America, Atlantic Ocean, Africa, India and the Indian Ocean

Being involved into various shear zones during continental drift, world tectonic plates area broken into smaller and smaller tectonic units with time. Contact zones of microplate are marked by pushup ranges and evolved orogenes, deep sedimentary basins, and transform fault scars on the oceanic floor. Most probably, a great percentage of fault-scars preserved on the surface of the Earth are somewhat older than Holocene, and ocean-floor fault scars are even older. The ‘quasi-neotectonic’ term points to this timing uncertainty.

Size of these crustal fragments is varying within a wide range, thus a plate hierarchy can be established according to their size ranges. In GSST we propose the simultaneous usage of conventional ‘plate‘ name to refer to the classic large plate tectonics units. For mid-size plate fragments we also keep the ‘microplate‘ term. In order to study the movement of the even smaller, but well individualized crustal fragments, we propose the use of the ‘nanoplate‘ term, without any direct reference to the absolute plate size range. Nanoplates usually appear in areas of long lasting contractional stress, and are made up of incipient or well developed plate duplex horses.

‘Pikoplates’ are the internal components of nanoplates, smaller with about one order of magnitude. These are the most important elements of structural hydrocarbon plays and are driving the regional distribution of hydrocarbon and ore accumulations. What we know as hydrocarbon trends, for example, are related usually to the presence of pikoplates.

Example: The Marquesas Mp-Ganges Mp kinematic chain is found south of the Cretaceous Panglobal Fracture Zone, and incorporates microplates of the Pacific Ocean, South America, Atlantic Ocean, Africa, India and the Indian Ocean.

Published in: Kovács, J.Sz., 2015 (in press), Elements of Global Strike-Slip Tectonics: a Quasi-Neotectonic Analysis, Journal of Global Strike-Slip Tectonics, v1., Szekler Academic Press, Sfintu Gheorghe.

Kinematic markers III: Extension Nodes

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Columnar basalts at Racoșul de Jos/ Alsórákos are yielding a 1200 ka to 600 ks old (Harangi et al., 2013)  effusive product in one of the  Perșani Mountain tension nodes, tracing the location of cross-cutting strike-slip  faults

Columnar basalts at Racoșul de Jos/ Alsórákos are yielding a 1200 ka to 600 ka old (Harangi et al., 2013) effusive product in one of the Perșani Mountain tension nodes, tracing the location of cross-cutting strike-slip faults

In the GSST approach, rising of magmas is related to the opening of crustal scale tension fractures. Because pure shear related stress field and deformation is unlikely to exist in nature, even within compressional belts there will exist some transtensional fracture components, which are characterized by significantly lower stress values. These tension fractures always form perpendicularly to the σ3 direction, and will serve as pathways for rising of magmas.

Cross-cutting fault systems are quite common in nature. While in regional compressional fault intersections stress nodes may form, in tensional fault intersections, extension nodes may appear. Here, in these extension nodes magmas have the highest chance to rich to the surface. As a consequence, volcanic craters are the best markers of regional extension nodes. In addition to volcanic craters, other parts of the volcanic build-ups may also serve as passive kinematic indicators, because of the pronounced hardness and brittleness of lavas and volcano sedimentary successions, in comparison to the surrounding environment.

Example: Columnar basalts at Racoșul de Jos/ Alsórákos are yielding a Pleistocene, 1200 ka to 600 ks old (Harangi et al., 2013) effusive product in one of the Perșani Mountain tension nodes, tracing the location of cross-cutting strike-slip faults.

Published in: Kovács, J.Sz., 2015 (in press), Elements of Global Strike-Slip Tectonics: a Quasi-Neotectonic Analysis, Journal of Global Strike-Slip Tectonics, v1., Szekler Academic Press, Sfintu Gheorghe.

Kinematic markers II: Stress Nodes

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Fig2Stress Node Map

There are at least 20 locations in Europe where the EMSC earthquake database is recording a spatial concentration of earthquake epicenters, like in the Vrancea Stress Node in Romania. We term these high activity seismogenic locations as ‘stress nodes’, because earthquake epicenters are sites of stress accumulation and release. High velocity bodies below a strike-slip zone are not uncommon (Hadley and Kanamori, 1977, in Kearey and Vine, 1996). Hadley has documented a high velocity body below the Transverse Ranges which was seismically active even at 100km.

A similar phenomenon happens in the Vrancea area, which serves as a meeting point for three different nanoplates, hence cross-cutting strike-slip faults. In this area, seismic gaps should be interpreted as oversteps of faults, as suggested in the case of the Calaveras fault (Reasenberg and Ellsworth, 1982). The occurrence of stress nodes in corner positions of microplates and nanoplates could be already predicted by GSST logics as well, without consulting the earthquake database, because significant structural deformation is also more likely to be present in corner locations.

Just nearby the Haute Provence Stress Node, in Southeastern France, 6 distinct deformation domains were isolated from the inversion of 89 focal mechanism (Baroux et al., 2001), which fits completely into the expected structural configuration, outlined by GSST techniques. This great variety of the recorded deformation domains is depicting the whole strike-slip stress field, including conjugate fault activity.

In the current study we have isolated the following Stress Nodes: 1) Vrancea Stress Node, Eastern Carpathians, Romania, 2) South Silesian Stress Node, Poland, 3) Lower Silesian Stress Node, Poland, 4) Po Valley Stress Node, Italy, 5) Cuneo Stress Node, Alpi-Marittime, Italy, 6) Haute Provence Stress Node, Alpes-de-Haute-Provence, France, 7) Pyrenees Stress Node, Spain, 8) Umbria Stress Node, Apennines, Italy, 9) Lipari Stress Node, Tyrrhenian Sea, Italy, 10) Monte Negro Stress Node, 11) Albanian Stress Node, 12) Gulf of Corinth Stress Node, Greece, 13) Keffalonia Stress Node, Greece, 14) Zakinthos Stress Node, Greece, 15) Crete Cluster of Stress Nodes, Greece, 16) Soma Stress Node, Turkey, 17) Şenköy Stress Node, Turkey, 18) Çameli Stress Node, Turkey, 19) Sapientza Stress Node, Greece, 20) Pamukkale Stress Node, Turkey, 21) Elazig Stress Node, Turkey, 22) Tabriz Stress Node, 23) Van Lake Stress Node, Turkey, 24) Qushm Stress Node, Iran, 25) Karakul Stress Node, Pamir Mts. China-Tajikistan, 26) Badakhshan Stress Node, Pamir Mts., Tajikistan, 27) Islamabad Stress Node, Himalaya Mts., Pakistan.

A systematic description of stress nodes listed above does not represent the objective of the present study.

Published in: Kovács, J.Sz., 2015 (in press), Elements of Global Strike-Slip Tectonics: a Quasi-Neotectonic Analysis, Journal of Global Strike-Slip Tectonics, v1., Szekler Academic Press, Sfintu Gheorghe.

Kinematic Markers I: Geomorphology

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Fig6 Torocko faultWorld topography is shaped by a complex interaction of various physical and chemical processes, where climate plays an important role. Different rocks may deform in very different way under same conditions. Structural stress has its important role in preconditioning the ultimate style of deformation in rocks, because fracture systems not only enhance, but may also drive erosional processes, especially in hard rocks, like limestones.

Fracture systems in lowlands may be hidden by young sediments; fault scarps in deserts are rapidly covered by mobile sand, while on oceanic passive margins delta systems may shed sediment over them. Fluvial channels also migrate autocyclically in the alluvial plain, hence cannot be used with automatism in geomorphological studies, however automatic techniques might be useful in delimiting recently uplifted areas. The higher the sediment input, the less chance we have to capture neotectonic events. Because on the central part of oceanic basins sediment input is extremely low, fault scars can be traced most easily on oceanic floors.

Despite the presence of inconvenient obstacles, there still remain several principles according to which geomorphological elements can be used in tracing worldwide quasi-neotectonic lineaments: 1) sharpness of geomorphological lineaments, 2) regional continuity, 3) linkage of linear geomorphological lineaments to other point-type markers, 4) inter-regional altitude contrast, 5) abrupt changes in watercourse of larger rivers, 6) abrupt changes in shorelines, 7) abrupt changes in mountain ridges, 8) presence of extensional or contractional duplexes.

In order to map strike-slip lineaments of the world we constructed digital elevation models from SRTM data for Eurasia and Northern Africa; oceanic domains and the other parts of the world were approximated using Google Earth data.

Example:

Trascăului Mountains, which delimit the Transylvanian basin from west, belong to the Western Transylvanides and form an obducted tectonic unit (Săndulescu, 1984) of the Apuseni Mts. range, exhibiting an oceanic (ophiolitic) basement. The study area around the Piatra Secuiului Peak is made up from slope and shelf-margin deposits of an Upper Jurassic-Lower Cretaceous carbonate platform (Săsăran, 2006). Given the well-cemented and compacted nature of the sedimentary succession, weathering plays only a secondary role in shaping the landscape of the Trascăului Mountains, thus regional neotectonic lineaments can be recognized at the local scale as well (Fig. 11, 12). Local fault lineaments delineated in plain view by geomorphological techniques on the Google Earth topography can be identified on field as well.

Published in: Kovács, J.Sz., 2015 (in press), Elements of Global Strike-Slip Tectonics: a Quasi-Neotectonic Analysis, Journal of Global Strike-Slip Tectonics, v1., Szekler Academic Press, Sfintu Gheorghe.

 

Mantle Origin of CO2 and Carbonate Budget of Oceans and Travertine Deposits – Examples from Turkey and Szeklerland

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The Pamukkale Travertine was deposited along the Burdur-Fethye fault zone. The main source of the significant amount of CO2 converted into bicarbonate should be of mantle origin, as proven by the nearby presence of borate deposits in the Bigadiç borate Basin.

Carbonate budget in the oceans of the Earth and in continental domains, as well, basically depends on the availability of CO2 in aqueous solutions, which might be a function of the mantle CO2 release by oceanic floor volcanic activity, in a given geological period. Wilson includes the enrichment in volatiles, halogens and CO2, among the general characteristics of continental rift zone magmatism (Wilson, 1989). Solubility of CO2 in magmas increases with pressure and magma alkalinity (Lowenstern, 2001).

Mantle origin CO2 is commonly present in active strike-slip zones, either as bicarbonate ion in aqueous solutions, or as dry CO2, and may give birth to significant continental carbonate deposits in the form of travertines, like in Pamukkale, Turkey, or the Yellowstone carbonate travertines in the USA. For example, the Ol Doinyo Lengai volcano of the East African Rift, Tanzania, is producing natrocarbonatite lava, accompanied by a flux of 6000–7200 tonnes CO2 d−1 (Koepenick et al., 1996). It is very difficult to disproof the mantle origin of these enormous CO2 fluxes.

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Small size Holocene carbonate tufa dome at Tălișoara/ Olasztelek, Szeklerland, Romania

Distribution of massive CO2 occurrences and that of larger carbonate tufa domes is related to deep crustal faults, and thus surface carbonate tufa deposits can be used to trace deep seated crustal faults, hence we consider them as integral parts of the GSST mapping techniques. A minor carbonate tufa dome is above from Tălișoara/ Olasztelek, which together with the Bálványos carbonate tufa domes delineate a major W to E trending deeper crustal fault system in Szeklerland/ Romania. Another synthetic fault to the master is coming from the Racoș/ Alsórákos neovolcanic area via the Ozunca Băi/ Uzonkafürdő carbonate tufa dome.

Published in: Kovács, J.Sz., 2015 (in press), Elements of Global Strike-Slip Tectonics: a Quasi-Neotectonic Analysis, Journal of Global Strike-Slip Tectonics, v1., Szekler Academic Press, Sfintu Gheorghe.

Accommodation Space Budget in the Mediterranean Area During the Messinian Salinity Crisis

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Recent shoreline  with uplifted Pleistocene sediments in Antalya, Turkey. History has recorded that the Manavgat River was navigable several centuries ago. While Venice is tectonically subsiding, Manavgat is rising.

The motor of basin opening mechanisms and subsequent subsidence in the Mediterranean Basin is best described in terms of strike-slip tectonics, related to the plate-velocity contrast of the African and Eurasian Plates during their eastward journey. In this approximation, the Mediterranean area represents an intercontinental mega-shear zone,  obviously with numerous transtensional zones, which evolved into isolated, small subbasins (Martínez-Garcia et al., 2013), featuring transform margins Tari et al. (2012), internal strike-slip zones (our experience in the Pantelleria Island area), and several push-up ranges, which in many parts of the Mediterranean area evolved into orogens, like in the case of the Atlas, Apennine, Alpine, Carpathian orogens. This continental scale tectonic evolution was enabled by several microplates and even nanoplates, in GSST wording.

The Atlas Microplate is found at the northern margin of the African Plate. Besides the High Atlas Nanoplate, which underlies the Atlas orogene, it includes two other, smaller nanoplates, the Gibraltar and Sicily Nanoplates. This microplate shows particularly intense strike-slip tectonics, and at the same time, we believe that it holds the main responsibilities for the accommodation space budget in the Mediterranean area, what has as a direct consequence that strike-slip tectonics should be considered as the main controlling factor for the Messinian Salinity Crisis, obviously exploiting the existing background climate factors.

According to Salé et al. (2012), the Mediterranean basins are showing very similar depositional trends and sedimentary architecture. They found however that the Late Messinian cyclicity of non-marine and fully marine sediments is related to climate changes, admitting that cyclicity is enhanced by tectonic activity in their study area, which is located over the Serrata-Carboneras strike-slip zone in Spain.

Looking after clues in the sedimentary record, we found that Late Messinian sediments are evidencing sedimentary intervals described as seismicites (Fortuin and Dabrio, 2008) and explosive fluid expulsion events (Bertoni and Cartwright, 2015).

In conclusion, it is more likely that causes of the Messinian Salinity Crisis should be attributed to the joint management of the Mediterranean accommodation space budget. Whatever is the subsidence of the individual subbasins, the total volume of available sea water counts in desiccating subbasins. It should be also noted that not every subbasin contains Messinian Salt, just those which met the desiccation criteria of the communicating vessels (subbasins).

Given the strike-slip related deformations recorded by the Atlas orogene, it is not hard to believe that the Atlas Microplate, certainly accompanied by the other microplates and orogens involved,  had a significant impact on  driving the vertical basin-floor oscillation, and ultimately changes in basin volume, all orchestrated by the regional strike-slip stress field.

Published in: Kovács, J.Sz., 2015 (in press), Elements of Global Strike-Slip Tectonics: a Quasi-Neotectonic Analysis, Journal of Global Strike-Slip Tectonics, v1., Szekler Academic Press, Sfintu Gheorghe.