scholarly journals Tectono-Sedimentary Cenozoic Evolution of the El Habt and Ouezzane Tectonic Units (External Rif, Morocco)

Geosciences ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 487
Author(s):  
Manuel Martín-Martín ◽  
Francesco Guerrera ◽  
Rachid Hlila ◽  
Alí Maaté ◽  
Soufian Maaté ◽  
...  
Keyword(s):  
Active Tectonics ◽  
Clay Mineralogy ◽  
Upper Jurassic ◽  
Deep Basin ◽  
Sedimentary Evolution ◽  
Unstable Slope ◽  
Definition Of ◽  
Depositional Architecture ◽  
Interdisciplinary Study ◽  
Mineralogy Analysis

An interdisciplinary study based on lithostratigraphic, biostratigraphic, petrographic and mineralogical analyses has been performed in order to establish the Cenozoic tectono-sedimentary evolution of the El Habt and Ouezzane Tectonic Units (External Intrarif Subzone, External Rif, Morocco). The reconstructed record allowed identification of the depositional architecture and related sedimentary processes of the considered units. The Cenozoic successions were biochronologically defined allowing, at the same time, identification of unconformities and associated stratigraphic gaps. The presence of five unconformities allowed for the definition of the main stratigraphic units arranged in a regressive trend: (1) lower Paleocene interval (Danian p.p.) assigned to a deep basin; (2) Eocene interval (lower Ypresian-lower Bartonian p.p.) from a deep basin to an external carbonate-siliceous platform; (3) lower Rupelian-upper Chattian p.p. interval deposited on unstable slope with turbidite channels passing upward to an external siliciclastic platform; (4) Burdigalian p.p. interval from a slope; (5) Langhian-Serravallian p.p. interval from slope to external platform realms. The petrography of the arenites and calcarenites allowed for the identification of the supplies derived from erosion of a recycled orogen (transitional and quartzose subtypes). The clay-mineralogy analysis indicates an unroofing (first erosion of Cretaceous terrains followed by upper Jurassic rocks) always accomplished by erosion of Cenozoic terrains. Several tectofacies checked in some stratigraphic intervals seem to indicate the beginning of deformation of the basement generating gentle folds and first activation of blind thrusts, mainly during the Paleogene. A preorogenic tectonic framework is considered as responseto the generalized tectonic inversion (from extension to compression) as frequently registered in the central-western peri-Mediterranean areas. The large volumes of reworked terrigeneous supply during the latest Oligocene-Miocene p.p. indicates the beginningsof the synorogenic sedimentation (foredeep stage of the basins) controlled by active tectonics.

scholarly journals The Cenozoic Malaguide Basin from Sierra Espuña (Murcia, S Spain): An Example of Geological Heritage

Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 34
Author(s):  
Santiago Moliner-Aznar ◽  
Manuel Martín-Martín ◽  
Tomás Rodríguez-Estrella ◽  
Gregorio Romero-Sánchez
Keyword(s):  
Middle Eocene ◽  
Geological Heritage ◽  
Passive Margin ◽  
Early Miocene ◽  
Late Oligocene ◽  
Deep Basin ◽  
Sedimentary Evolution ◽  
Early Oligocene ◽  
Upper Oligocene ◽  
Very High

The Cenozoic Malaguide Basin from Sierra Espuña (Internal Betic Zone, S Spain) due to the quality of outcropping, areal representation, and continuity in the sedimentation can be considered a key-basin. In the last 30 years, a large number of studies with very different methodological approaches have been done in the area. Models indicate an evolution from passive margin to wedge-top basin from Late Cretaceous to Early Miocene. Sedimentation changes from limestone platforms with scarce terrigenous inputs, during the Paleocene to Early Oligocene, to the deep basin with huge supplies of turbidite sandstones and conglomerates during the Late Oligocene to Early Miocene. The area now appears structured as an antiformal stack with evidence of synsedimentary tectonics. The Cenozoic tectono-sedimentary basin evolution is related to three phases: (1) flexural tectonics during most of the Paleogene times to create the basin; (2) fault and fold compartmentation of the basin with the creation of structural highs and subsiding areas related to blind-fault-propagation folds, deforming the basin from south to north during Late Oligocene to Early Aquitanian times; (3) thin-skin thrusting tectonics when the basin began to be eroded during the Late Aquitanian-Burdigalian. In recent times some works on the geological heritage of the area have been performed trying to diffuse different geological aspects of the sector to the general public. A review of the studies performed and the revisiting of the area allow proposing different key-outcrops to follow the tectono-sedimentary evolution of the Cenozoic basin from this area. Eight sites of geological interest have been selected (Cretaceous-Cenozoic boundary, Paleocene Mula Fm, Lower Eocene Espuña-Valdelaparra Fms, Middle Eocene Malvariche-Cánovas Fms, Lowermost Oligocene As Fm, Upper Oligocene-Lower Aquitanian Bosque Fm, Upper Oligocene-Aquitanian Río Pliego Fm, Burdigalian El Niño Fm) and an evaluation has been performed to obtain four parameters: the scientific value, the educational and touristic potential, and the degradation risk. The firsts three parameters obtained values above 50 being considered of “high” or “very high” interest (“very high” in most of the cases). The last parameter shows always values below 50 indicating a “moderate” or “low” risk of degradation. The obtained values allow us considering the tectono-sedimentary evolution of this basin worthy of being proposed as a geological heritage.

Whole-rock and clay mineralogy as paleoenvironmental tracers during the Late Holocene sedimentary evolution of the Doñana National Park (SW Spain)

2020 ◽  
Vol 197 ◽  
pp. 105780
Author(s):  
Francisco Ruiz ◽  
Manuel Pozo ◽  
María Isabel Carretero ◽  
Juan Manuel Muñoz ◽  
María Luz González-Regalado ◽  
...  
Keyword(s):  
National Park ◽  
Late Holocene ◽  
Clay Mineralogy ◽  
Doñana National Park ◽  
Sw Spain ◽  
Sedimentary Evolution

scholarly journals New charophytes from the Upper Jurassic of the Lusitanian Basin (Portugal)

2003 ◽  
Vol 22 (2) ◽  
pp. 113-126 ◽  
Author(s):  
Ricardo Pereira ◽  
Monique Feist ◽  
Ana C. Azerêdo
Keyword(s):  
Upper Jurassic ◽  
West Central ◽  
Central Portugal ◽  
Definition Of ◽  
Lusitanian Basin

Abstract. In the Lusitanian Basin (west-central Portugal), Upper Jurassic (Oxfordian) sediments were investigated in order to identify palaeontological assemblages of charophytes. Systematic studies were undertaken on specimens obtained from four field sections (Pedrógão, Vale de Ventos, Memória and Valverde). These studies revealed the presence of new forms of Porocharaceae (Porochara pedunculata n. sp) and of forms previously unknown in this region (Auerbachichara cf. saidakovskyi), as well as P. raskyae, P. minima, P. fusca, P. sulcata, P. kimmeridgensis, Aclistochara longiformis and Porochara sp. Comparison of the charophyte palaeofloras recognized in all of the studied sections has allowed the definition of three different assemblages which, coupled with other data, help to correlate these successions of Early (?) to Middle (Late?) Oxfordian age.

Estimating porosity and permeability in the Springbok Sandstone, Surat Basin (Queensland), using new wireline log-based workflow

2021 ◽  
Vol 61 (2) ◽  
pp. 720
Author(s):  
Kasia Sobczak ◽  
Heinz-Gerd Holl ◽  
Andrew Garnett
Keyword(s):  
Upper Jurassic ◽  
Coal Seams ◽  
Impact Prediction ◽  
Reservoir Models ◽  
Resistivity Logs ◽  
Porosity And Permeability ◽  
Sandstone Formation ◽  
Definition Of ◽  
Coal Measures

The Upper Jurassic Walloon Coal Measures of the Surat Basin (Queensland) host some of the most prominent coal seam gas (CSG) resources in Australia. The Walloon Coal Measures are directly overlain by the Springbok Sandstone formation, historically referred to as a regional aquifer. An increasing number of studies and industry models suggest relatively limited hydraulic connectivity within the formation and between it and the underlying coal measures, due to extreme lithological heterogeneity. Accurate evaluation of the permeability, as well as lateral and vertical continuity of the lithological units within the Springbok Sandstone, is critical in reservoir models that form the basis of reasonable aquifer protection practices and impact prediction. This study presents a wireline log-based workflow applied to identify permeable zones within the Springbok Sandstone in 31 CSG wells across the Surat Basin that allows robust estimations of porosities and Klinkenberg permeabilities. The workflow primarily utilises spontaneous potential, density, neutron and resistivity logs, and was developed by integrating current industry practices implemented by operators on a local scale to identify risk (permeable) zones in the vicinity of targeted coal seams. The results of this case study indicate that permeable zones within the interval are volumetrically minor (on average 25% N/G) and likely isolated, with Klinkenberg permeabilities rarely exceeding 10–20mD. This evidence for low hydraulic connectivity, as well as significant local variations in the character of the Springbok Sandstone, suggests that the definition of the formation as a regional, continuous aquifer and the way it is modelled needs to be revised.

scholarly journals Late Permian to Late Jurassic “microproblematica” of Saudi Arabia: Possible palaeobiological assignments and roles in the palaeoenviromental reconstructions

GeoArabia ◽  
2013 ◽  
Vol 18 (1) ◽  
pp. 57-92
Author(s):  
Geraint Wyn Hughes
Keyword(s):  
Late Jurassic ◽  
Decapod Crustacean ◽  
Upper Jurassic ◽  
Environmental Preferences ◽  
Shallow Marine ◽  
Faecal Pellets ◽  
Marine Carbonates ◽  
Shallow Subtidal ◽  
Definition Of ◽  
Normal Salinity

ABSTRACT Palaeoenvironmental interpretation of Permian and Jurassic intertidal to very shallow-marine carbonates is difficult where typical shallow-marine microfossils are either absent or sparse. A collection of microfossils originally considered as “microproblematica” because of their uncertain biological affinities are, however, often present. These include species of Aeolisaccus, Gakhumella, Prethocoprolithus, Thaumatoporella, Favreina and Terebella. Observations of their vertical distribution and relationship with carbonate fabrics reveal their environmental preferences, and these contribute to palaeoenvironmental interpretation within a spectrum of very shallow-marine settings that previously precluded refinement. The recognition of high-frequency depositional cycles and definition of cryptic reservoir layering in such shallow to marginal-marine carbonates is now facilitated by the use of these microfossils from the Khuff, Hanifa, Jubaila, Arab and Hith formations. Aeolisaccus dunningtoni is interpreted as either a fossilised cyanobacterial tube or possible foraminifera of Early Permian to Late Jurassic age. It is well represented within mudstones, wackestones and packstones of supratidal flats to very shallow intertidal palaeoenvironments with occasional freshwater influence. The microbialitic Gakhumella cf. huberi is locally present in these Upper Jurassic intertidal to very shallow-marine bioconstructions. Prethocoprolithus centripetalus is a faecal ribbon, considered to be of mollusk origin, within shallow subtidal grainstones and packstones. Thaumatoporella parvovesiculifera is considered a green alga that is typically found encrusting biocomponent fragments. It ranges from the Middle Triassic to Upper Cretaceous and is extensively present in intertidal, possibly hypersaline to shallow-marine, normal salinity lagoon grainstones and mud-lean packstones. Certain types of the distinctively canaliculate, microcoprolitic decapod crustacean faecal pellets, of the genus Favreina, are diagnostic of Late Jurassic intertidal to shallow subtidal conditions found within packstones. Terebella lapilloides is an agglutinated polychaete tube, typical of Upper Jurassic intertidal to shallow-marine packstones.

scholarly journals Active Tectonics And Active Faults: Why These Terms Still Lack Consensus On Definitions

2020 ◽  
Vol 70 (1) ◽  
pp. 125-132
Author(s):  
A. A. Shah ◽  
◽  
Batmanathan Navakanesh ◽  
Keyword(s):  
Active Faults ◽  
Active Tectonics ◽  
Historical Background ◽  
Geological Structures ◽  
Clear Cut ◽  
Traditional Definition ◽  
Fracture Systems ◽  
Typical Time ◽  
Major Strike ◽  
Definition Of

The terms: Active tectonics and active faults have emerged as some of the most frequently used terms in geological literature, and traditionally, the main purpose of these definitions has historically remained devoted to either geological or engineering uses. However, most of the existing literature on the definitions has been gathered since >230 years that were spent on the understanding of the science of earthquakes, but a clear-cut consensus lacks on how to define active tectonics and active faults, for various reasons that are discussed at length here. Therefore, this paper presents a brief overview of the terms with a motivation to rekindle the discussion on what is considered active in tectonics. It also explores whether the traditional definitions are valid or not, and should we look for other alternatives. We present a brief historical background knowledge and understanding on the active faults, and particularly in some of the tectonically stable and presumably inactive portions of the Earth’s crust. The two major strike-slip faulting events (Mw 8.6 and Mw = 8.2) that have occurred in the Wharton Basin, Indian Ocean in 2012 are discussed in detail. The events are specially quoted to make a case for reactivation of old fracture systems as these earthquakes ruptured the ~30-90 Ma old Indian oceanic crust. This clearly demonstrates that much older geological structures could also be re-activated, thereby questioning the traditional definition of the typical time span that is used to define active tectonics and active faults.

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