The Westernmost Tethys Blog Geology mapping, basin analysis and 3D modeling

06/02/2020

Terminology revision of AlKaPeCa and Mesomediterranean Microplate

Filed under: geodynamic evoluton,paleogeography,Tethys — Tags: , , , — messinianalicante @ 2:15 PM

The use of terms strictly related to the original formulation of different models caused, in some cases, inaccuracies in the univocal identification of some main palaeogeographic elements.

Bouillin et al. (1986) introduced the acronym AlKaPeCa for a lithospherical block formed by Alboran-Kabylian-Peloritan-Calabrian Internal Zones, Alpine units. According to them the relationships between AlKaPeCa and the Maghrebian Flysch Basin  may be synthesized as follows:‘ the only possible oceanic zone known between Western Europe and Africa, at the Jurassic time, corresponds to the basement of the Flyschs which was located southward of AlKaPeCa’ .

 Many palaeogeographic interpretations of the Jurassic-Cretaceous evolution of the Betic, Maghrebian and Apennine Chains have been roughly grouped into two main general families: (1) Type A  models: they state the presence of a single oceanic area (i.e., the Tethys) located between the African and European Plates; (2) Type B  models: they consider the occurrence of two oceanic branches of the Tethys surrounding one or more microcontinents located between the African and European Plates. Both classes of models imply a different evolution during the Pangea breakup and during the Cretaceous-Cenozoic convergence. According to Type A  models the Pangea broke with a single oceanic branch located between Europe and Africa, meanwhile according to Type B  models the fragmentation was more complex leading to two oceanic branches with several microplates located between Europe and Africa.

Reproduction of some original figures from literature concerning Type B models (A to D boxes) showing some inappropriate use of terms. The figures presented show Type B models which use the term AlKaPeCa instead of Mesomediterranean Microplate (MM). (a). Palaeogeographic sketch map (at Jurassic times) and evolutionary cross sections from Late Jurassic to Middle Miocene (after Michard et al. 2002); (b). Evolutionary palaeogeographic cross sections from Eocene to Oligocene (after Viti et al. 2009); (c). Evolutionary palaeogeographic sketch maps from 55 to 45 My (after Schmid et al. 2017); (d). Palaeogeographic sketch map at Early Miocene times (after Leprêtre et al. 2018).

According to Guerrera et al. (2019)  the original meaning of AlKaPeCa should be reserved to indicate a detached piece of the European Margin while the Mesomediterranean Microplate  should be used exclusively for the independent microplate even though during the Maghrebian- Apennine orogeny these elements actually coincide to form the Internal Zones of these chains. For this reason, the use of this acronym is not appropriate for models which consider the occurrence of an independent microplate surrounded by different oceanic branches of the Tethys since Mesozoic. A more common name used in literature for this microplate is the Mesomediterranean Microplate.

Cite as: Guerrera, F., Martín-Martín, M., and Tramontana, M. (2019): Evolutionary geological models of the central-western peri-Mediterranean chains: a review. International Geology Reviews. 1-22. doi: 10.1080/00206814.2019.1706056

05/20/2020

Evolutionary geological models of the central-western peri-Mediterranean chains

Filed under: paleogeography,Tectonosedimentary model,Tethys — Tags: , , , — messinianalicante @ 8:06 AM

Two main groups of geological models presented over the last four decades on the paleogeographic, paleotectonic and geodynamic eo-Alpine and neo-Alpine evolution of the central-western Mediterranean area were compared. The comparison was carried out mainly considering the main stratigraphic, sedimentological, petrographic, structural and plate tectonic constraints. Moreover, recent geophysical interpretations and reconstructions were also considered with an aim of presenting all the different results. The models can roughly be grouped into two main classes. First family considers the presence of the Mesozoic Tethyan Ocean, where a single oceanic basin is located between Africa and Europe and from which both eo-Alpine and neo-Alpine chains were generated during the Cretaceous to Miocene time span. Conversely, the other class considers the occurrence of at least two Tethyan oceanic branches (or with thinned continental crust) since the Jurassic, separated by one or more microcontinents. The pros and cons of both classes of models are presented. Progressive innovations and improvements to the two groups of models were proposed over the years. However, because the modelsare based on different data sets resulting from basic geological studies or obtained by means of other approaches, they often do not integrate easily.This caused interpretative difficulties and terminological uncertainties for their comparison, and completely different models were considered equivalent and, sometimes, the same terminology was used indifferently to identify different geological subjects. The main differences between the examined models concern the kinematic reconstructions and by hence in the paleogeographic and paleotectonic interpretations. The discussion presented in this paper aims at contributing to clarify and update the state of knowledge on this controversial topic.

General framework and correlations of the main evolutionary stages and geodynamic events (Triassic to Pliocene) of the eoalpine and neo-alpine systems reconstructed in different sectors of the central-western peri-Mediterranean chains (A to C boxes). (a). Palaeogeographic sketch map of the Central-Western Tethys (at Jurassic times) with the location of the sectors mentioned in the work; (b). Sketch map of present times showing the central-western peri-Mediterranean chains with the location of the sectors mentioned in the work; (c). Main evolutionary stages and geodynamic events (Triassic to Pliocene) of the different sectors of the central-western peri-Mediterranean chains.

Cite as: Guerrera, F., Martín-Martín, M., and Tramontana, M. (2019): Evolutionary geological models of the central-western peri-Mediterranean chains: a review. International Geology Reviews. 1-22. doi: 10.1080/00206814.2019.1706056

01/29/2020

Compactation in sedimentary basins

Filed under: basin analysis,simulation — Tags: , , — messinianalicante @ 8:59 AM

Subsidence analysis is an important technique in the study of sedimentary basins but the effects of compaction must be “backstripped”. The compaction of sediments is also of importance for petroleum and water reservoir research with very important economic derivations. Most methods for calculating compaction are based on empirically derived porosity-depth relationships from a variety of known sediment types. The challenge of this paper is to apply alternative methods for calculating compaction in sedimentary basins based on: physical calculation with elastic by Steinbrenner, oedometric and change of the specific weight of the sediment methods; and use of Loadcap software.

The Triassic to Lower Miocene 3025m thick succession of Sierra Espuña (SE Spain) is used as case study for the calculations. In this succession former mineralogical studies and apatite fission-track suggested an original thickness between 4 and 6km. The validity of each one of the proposed methods is discussed, as well as, compared for the whole succession compaction but also separately for hard vs soft sediments and for thick vs thin beds.

Accumulate thickness-age (My) graphic with the comparative of the measured thickness and the results of original accumulate thickness along time of the studied succession after decompaction with the whole methods. The mean thickness with the whole methods is also represented with dash line. Key: ESM: elastic by Steinbrenner; SWM: specific weight of the sediment methods; OM: oedometric method; PCM: porosity change method (Bond et al., 1983); LSM: use of Loadcap software method.

The compaction values obtained with the alternative methods are similar to those resulting with the lower-limit curves of the porosity-depth change method. The new methods have provided values slightly higher than 4km for the whole original thickness using the geotechnical software and the change of the sediments specific weigh methods; meanwhile values below 4km for other methods. So, in our opinion, the geotechnical software and the change of the specific weight of the sediment methods are compatible with mineralogical constraints and also, the input data are usually better known and easier to determinate. Otherwise, the elastic method seems only accurate for soft sediments; meanwhile the oedometric method is highly influenced by the thickness of the considered beds.

 

Cite as: Martín-Martín, M., and Robles-Marín, P. (2020): Alternative methods for calculating compaction in sedimentary basins. Mar. Pet. Geol. 113, 104132. doi: 10.1016/j.marpetgeo.2019.104132

01/17/2020

Latest Chattian-Langhian Volcano- Sedimentary Event

Filed under: oligocene,Tethys — Tags: , — messinianalicante @ 10:09 AM

High amounts of Chattian-Langhian orogenic magmatism have generated volcaniclastic deposits that are interbedded within the penecontemporaneous sedimentary marine successions in several central-western peri-Mediterranean chains. These deposits are widespread in at least 41 units of different basins located in different geotectonic provinces: (1) the Africa-Adria continental margins (external units), (2) the basinal units resting on oceanic or thinned continental crust of the different branches of the western Tethys, (3) the European Margin (external units), and (4) the Western Sardinia zone (Sardinia Through units). The emplacement of volcaniclastic material in marine basins was controlled by gravity flows (mainly turbidites; epiclastites) and fallout (pyroclastites). A third type comprises volcaniclastic grains mixed with marine deposits (mixed pyroclastic-epiclastic). Calc-alkaline magmatic activity is characterized by a medium- to high-potassium andesite-dacite-rhyolite suite and is linked to complex geodynamic processes that affected the central-western Mediterranean area in the ∼26 to 15 My range. The space/time distribution of volcaniclastites, together with a paleogeographic reconstructions, provide keys and constraints for a better reconstruction of some geodynamic events. Previous models of the central-western Mediterranean area were examined to compare their compatibility with main paleotectonic and paleogeographic constraints presented by the main results of the study. Despite the complexity of the topic, a preliminary evolutionary model based on the distribution of volcaniclastites and active volcanic systems is proposed.

Paleogeographic and paleotectonic evolutionary model of the central-western Mediterranean region sketched in three steps (modified from Schettino and Turco 2006, 2011; Guerrera and Martín-Martín 2014). A, Late Oligocene. B, Early Miocene. C, Middle Miocene p.p. (Langhian). The relationships between sedimentary basins and volcaniclastites, and the distribution of active volcanic systems during the late Oligocene-middle Miocene p.p. (Langhian) are shown.

Cite as: Martín-Martín, M., Guerrera, F., and Tramontana, M. (in press): Geodynamic Implications of the Latest Chattian-Langhian Central-Western Peri-Mediterranean Volcano-Sedimentary Event: A Review.  The Journal of Geology 128:1, 29-43. doi: 10.1086/706262

12/30/2019

Oligo-Miocene evolution of the Paratethyan branches

A comparison of the stratigraphic record between two different branches of the Tethys is attempted for the first time. This study concerns the main Oligocene-Miocene tectono-sedimentary events in the Cenozoic units of the Moldavidian Basin (Romanian Eastern Carpathians) and the Maghrebian Flysch Basin (Maghrebian Chain and its lateral extension in the Betic and Southern Apennine Chains). Both basins are characterized by three main general Oligo-Miocene successions (internal, mixed, and external) corresponding to three subdomains controlled by the geological evolution of opposite plate (or microplate) margins and affected by a similar tectonic evolution. The successions of the three subdomains of the two basins show very similar features regarding stratigraphic records (lithofacies and petrofacies associations, unconformities, marker-levels, age), and the space-time sediment supply diversification (i.e., immature and super-mature arenites coming from opposite margins). Furthermore, pre-, syn- and post-orogenic successions have been identified in the geological reconstructions of both basins. The tectonic control on depositional processes (i.e., a large amount of siliciclastic supply confined in restricted time ranges, widespread volcaniclastites linked to acid-intermediate penecontemporaneous volcanic activity), and the appearance of indicators of syn-sedimentary tectonic activity (turbidites, slumps, and olistostromes) result in correlable events related to deformation phases that in turn are indicative of a similar evolution. Also, the basinal evolutionary stages (i.e., beginning of terrigenous supply, thrust-top basin formation and gravitational sliding, molassic and/or intramontane sedimentary cycles), the timing of deformation phases (drifting, foredeep), and geotectonic events (from extension to compression and post-orogenic deformation) seem to be similar. All results are encompassed in an evolutionary geodynamic model considered in the context of the Africa-Europe convergence where intermediate microplates are involved. This complex framework implies a progressive reorientation of convergence direction of these microplates that occurs during similar geodynamic events leading to the closure of the western Tethys Ocean and its related late-Alpine branches. This comparative approach, if applied to similar evolutionary phases of other mountain chains, can be useful for different geological contexts of other orogenic belts, especially to check the major general geological constraints for their evolution.

Paleogeographic evolutionary sketches of thewestern Tethyan domains for Cretaceous (A), Oligocene (B), Aquitanian (C) and Langhian (D). Relationships between microplates and basins, tectonic transport, and opening and closing of basins are shown (based also on data fromGuerrera et al., 1993, 2012a, 2012b, Belayouni et al., 2009; Amadori et al., 2012; Guerrera and Martín-Martín, 2014).

Cite as: Martín-Martín, M., Guerrera, F., Miclăuș, C., and Tramontana, M. (2020): Similar Oligo-Miocene tectono-sedimentary evolution of the Paratethyan branches represented by the Moldavidian Basin and Maghrebian Flysch Basin. Sedimentary Geology 396: 105548

12/17/2019

New model for the Betic Flysch Basin

Filed under: Betics,Campo de Gibraltar — Tags: , — messinianalicante @ 1:06 PM

The Flysch Complex extends, with equivalent stratigraphic and tectonic features, from the Betic Cordillera to the Rif, Argelian and Tunisian Tells, Sicily, Calabria and the southern-central Apennines. In the Betic Chain, it extends from the Campo de Gibraltar to the Vélez Rubio-Lorca region. This complex is a thrust-and-fold system (when structurally organised) or a tectonosedimentary mélange (when showing a rather chaotic structure). In the western Betic Cordillera, the Campo de Gibraltar Flysch Complex widely overthrusts the External Zones and, in turn, the Alborán Domain (Frontal Units in particular) thrusts onto it.

The Flysch Complex is mainly made of Lower Cretaceous to lower Burdigalian turbiditic siliciclastic (and subordinately carbonatic) sandstones interlayered with varicoloured clays. Since the latest Oligocene the successions show synorogenic character.

The Cretaceous successions of the Alborán (internal domain in the figure) domain record the post-rift evolution of the proximal to distal parts of a divergent Tethyan paleomargin, while those of the Campo de Gibraltar Flysch Complex record the evolution of the oceanic basin. The Alborán and the Campo de Gibraltar Flysch Complex domains were later transformed into a convergent continental margin (Oligocene to Early Miocene) that later evolved to a collisional setting (Middle to Late Miocene).

Paleogeographic and geodynamic evolutionary model of the Western Mediterranean area during the deposition and deformation of the syn–orogenic deposits of the Flysch units.

Cite as: Jabaloy Sánchez, A., Martín-Algarra, A., Padrón-Navarta, J.A., Martín-Martín, M., Gómez-Pugnaire, M.T., López Sánchez-Vizcaíno, V., Garrido, C.J., 2019. Lithological Successions of the Internal Zones and Flysch Trough Units of the Betic Chain, in: Quesada, C., Oliveira, J.T. (Eds.), The Geology of Iberia: A Geodynamic Approach: Volume 3: The Alpine Cycle. Springer International Publishing, Cham, pp. 377–432. https://doi.org/10.1007/978-3-030-11295-0_8

12/13/2019

Jimenez de Cisneros exhibition at Crevillent

Filed under: Sin categoría,Tectonosedimentary model — Tags: , — messinianalicante @ 2:07 PM

In the Crevillent town takes place an exhibition on the geologist Daniel Jimenez de Cisneros celebrating the 100 years of the publication of the first geological study of the Crevillent Sierra.

The University of Alicante has been collaborating in the exhibit 15-years after the 2004-tribute-simposium to Don Daniel Jimenez de Cisneros. The link bellow show two videos made for the event.

 

Catoon trailer:

 

link to the facsimil-book published:

www.academia.edu/41114909/

11/19/2019

shallow water stratified simulation

Filed under: simulation — Tags: , — messinianalicante @ 2:28 PM

The computational simulation of shallow stratified fluids is a very active research topic because these types of systems are very common in a variety of natural environments. The simulation of such systems can be modeled using multilayer shallow-water equations but do impose important computational requirements, especially when applied to large domains.

General Purpose Computing on Graphics Processing Units (GPGPU) has become a vivid research field due to the arrival of massively parallel hardware platforms (based on graphics cards) and adequate programming frameworks which have allowed important speed-up factors with respect to not only sequential but also parallel CPU based simulation systems.

In this work we present simulation of shallow stratified fluids with an arbitrary number of layers using GPUs. The designed system does fully adapt to the many-core architecture of modern GPUs and several experiments have been carried out to illustrate its scalability and behavior on different GPU models. We propose a new multilayer computational scheme for an underlying 2D mathematical model. This scheme is capable of handling an arbitrary number of layers. The system adds no overhead when used for two-layer scenarios, compared to an existing 2D system specifically designed for just two layers.

In this image we show a scheme for the initial configuration of a 6 layers simulation, along with a screenshot of the program.

The GPU computes the evolution in time of the interfaces between several layered fluid types (for a given initial configuration) and displays those interfaces as solid surfaces, as soon as the output from each computing step is available. The user can rotate the view interactively, so he can better observe the layers’ evolution.

Here you can view two screen-shots taken from the simulation program while running. First one the initial layers configuration is shown.

Then It is shown the resulting layers configuration after the simulation has been running for some time.

These screen captured videos (see links below) show the simulation program running in real-time, for various scenerarios. You can observe how the user is able to manipulate the view:

https://youtu.be/MXl6b675uXQ

 

Cite as:  Miguel Lastra, Manuel J. Castro Díaz, Carlos Ureña, Marc de la Asunción (2017):  Efficient multilayer shallow-water simulation system based on GPUs. Mathematics and Computers in Simulation, Volume 148, 2018,  48-65. DOI: https://doi.org/10.1016/j.matcom.2017.11.008

11/12/2019

Field trip to Granada

Filed under: Betics — Tags: , — messinianalicante @ 3:03 PM

Students of the third course of Geology of the Alicante University within the subject of Mapping 2: visit Benalúa in the Guadix basin.

The visit took place from October 23th until 26th of 2019 and the professor in charge was Manuel Martín-Martín.

 

10/29/2019

Regional geology field trip to Teruel

Filed under: Iberian range,Paleozoic — Tags: , , — messinianalicante @ 6:36 PM

Students of the third course of Geology of the Alicante University within the subject of Regional Geology: visit Jarafuel triassic section, Aguaton jurassic section, Murero paleontological site, Fombuena section, Santa Cruz Paleozoic Seas Museum, Ojos Negros Mine, and Orea-Checa road Hirnatian section.

Student in the Aguatón “tunnel” section

The visit took place from 16 to 19 October of 2019 and the professors in charge were Juan Alberto Pérez-Valera and José Enrique Tent-Manclús.

Zoophycos found in the Devonian Santa Cruz de Nogueras Formation, near the village of Santa Cruz de Nogueras. The specimen is now in the Paleozoic Seas Museum.

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