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[Display omitted] • Tectonometamorphic association of Ronda peridotites and overlain high-grade crustal rocks indicate lithospheric attenuation. • I Permian low- to medium-pressure and high-temperature rifting-related metamorphism and partial melting. • Pre-Alpine HT-LP metamorphism and mantle exhumation in western Betics. Recent geological mapping conducted in the Ronda Peridotites (Betic Cordillera, S Spain) has revealed a systematic field correlation between lower crustal metamorphic units and different tectono-metamorphic domains of the ultramafic massif. Mylonitic and highly tectonized Spl ± Grt peridotites (i.e., Grt-Spl mylonite and Spl tectonite domains), which are considered to be derived from a thick continental lithosphere, are in contact with garnet-bearing gneisses (i.e., kinzigites) of the Jubrique unit along a narrow but continuous mylonitic shear zone. Phase equilibrium calculations indicate that the metamorphic rocks of the Jubrique unit are consistent with an initial continental setting characterized by normal crustal thicknesses, which underwent two melting events. The first melting occurred at 0.9–1.0 GPa / 770–800 °C and resulted in 13 %melt, while the second one took place at shallower crustal conditions (0.4–0.5 GPa and 710–765 °C) and led to more restricted melt production (2–3 %melt). In contrast, the Spl ± Pl peridotites (Pl-tectonite domain), which are stable only at shallowest mantle levels within a highly extended continental lithosphere, are consistently found exposed in contact with heterogeneous granites and migmatites of the Guadaiza unit. According to new thermodynamic modeling, the Guadaiza metamorphic rocks record a single melting event characterized by a theoretical melt production of 6 to 11 % at the base of a very thin continental crust (ca. 0.3 GPa and 675–710 °C). This process was likely facilitated by influx of external water, necessary to generate high melt fractions observed in the diatexites. The systematic correlation observed between crustal metamorphic units, consistently overlaying the mantle rocks, and specific ultramafic domains of the Ronda massif, suggests that their juxtaposition primarily resulted from the severe extension of the continental lithosphere. U-Pb radiometric dating of zircons from gneisses, migmatites, and heterogeneous granites in the middle crustal rocks of the Guadaiza unit indicates that extensional processes, crustal anatexis, and melt stagnation occurred at around 280 Ma. Comparison of these new radiometric ages with previous results from the Jubrique unit suggests that a Permian high-temperature / low- to medium-pressure event uniformly affected the crustal units over the Ronda Peridotites. This event coincided with the formation of characteristic ultramafic mineral assemblages within the Ronda massif and provides evidence for the interaction between upper mantle rocks and lower- to mid-crustal metamorphic rocks during this period. [ABSTRACT FROM AUTHOR]

This study uses heavy detrital minerals to determine actualistic fluvial and beach sand provenance across the Betic Cordillera (Spain), along the coast from Almeria to Marbella. The Betic Cordillera, primarily composed of metamorphic rocks to the east, supply an assemblage dominated by almandine and graphite, with a longshore dispersal from Almeria to Malaga. Buergerite and hypersthene indicate the provenance of calcalkaline lavas east of Cabo de Gata. The western part of the Betic Cordillera, which comprises the Ronda Peridotite Complex, supplies a chromite and diopside assemblage, with a dispersal from Marbella to Algeciras. Considering these mineralogical suites, the effects of source rock compositions and weathering are evaluated. The heavy mineral species mirror the mineralogy of the source rocks of local outcrops and wider source terranes. The fluvial heavy mineral suites do not differ significantly from those in the beaches except for some unstable species. Unstable species such as olivine, pyroxene, and amphibole do not show evidence of loss because of elevated topography and semiarid climate, which do not affect heavy minerals. This contribution also evaluates the potential of some heavy detrital species as ideal pathfinders in searching for diamonds. [ABSTRACT FROM AUTHOR]

[Display omitted] • We provide detrital Zrn U-Pb ages from the Ronda peridotites' crustal hanging wall. • The studied crustal sequences likely derive from the Iberian Massif. • Results indicate a Permian or younger crustal emplacement of the Ronda peridotites. Detrital zircon geochronology is frequently used for sediment provenance analysis in orogenic belts, but it can also be applied to locate the boundary between basement and sedimentary cover in successions and tectonometamorphic units where the paleontological record is missing, and primary stratigraphic relationships have been erased by intense deformation and/or metamorphism. This is critical to differentiate metamorphic mineral associations, P-T conditions and deformational events associated with superposed orogenic cycles. In this work, detrital zircon geochronology has been applied to the Ronda peridotites' crustal hanging wall (hinterland of the Alpine Betic Cordillera, southern Spain), apparently made up of two major tectonic units – the Jubrique unit and the Maláguide complex – separated by a major Alpine tectonic contact camouflaged in between low-grade metamorphic rocks. Our results show that pre-Paleozoic peaks (c. 650, 1000, 2000, and 2600 Ma) are common along the entire studied crustal sequence, and Paleozoic ages are only recorded in the upper part of the Jubrique unit (c. 290, 350, and 475 Ma) and in the Maláguide complex (c. 350 and 475 Ma). Thus, the Paleozoic rocks of the Maláguide complex, constituting the highest crustal unit overlying the Ronda peridotites, represent syn -to-late orogenic Variscan sediments deformed and slightly metamorphosed prior to the Alpine cycle. In contrast, the underlying Jubrique unit is made of a post-Variscan sedimentary cover deposited on a Variscan basement, with the contact between both (hidden unconformity?) located within low- to medium-grade schists. These data support the presence of a major tectonic contact between the Maláguide complex (Late Carboniferous maximum depositional ages) and the Jubrique unit (Early Permian maximum depositional ages), i.e. the Maláguide complex would have overthrust the Jubrique unit during the Alpine orogeny. These results indicate a Permian or younger exhumation/emplacement up to crustal levels of the Ronda peridotites subcontinental mantle slab. Altogether, these detrital zircon age spectra support a relatively, but not entirely local derivation of the studied crustal sequences (fragments of the Iberian Massif) and suggest some Mesozoic drifting with respect to its present position. Nonetheless, the different age distribution of the Paleozoic populations between the Jubrique (Alpujárride complex) and Maláguide samples suggests that the former deposited relatively close to other samples from the eastern-central Alpujárride complex and Nevado-Filábride complex, which, in turn, show strong similarities with the Cantabrian zone and NE Iberia (Iberian Massif). In contrast, the Maláguide samples were probably deposited close to the Ossa-Morena Zone (Iberian Massif). Thus, Alpujárride/Nevado-Filábride and Maláguide complexes would have been juxtaposed during the Triassic-Cretaceous Neotethys rifting/drifting and/or the subsequent Alpine collisional events. [ABSTRACT FROM AUTHOR]

A hydrochemical and mineral study of groundwaters and damaged rocks from the Tíscar and Larva fault zones (Betic Cordillera, Iberian Peninsula) was carried out in order to (a) describe the physical and chemical properties of the groundwaters; (b) recognize significant locations with deep-origin fluids related to active tectonics; (c) and to describe the water–rock interaction and the neoformation of clay mineral processes and their importance in the seismicity of the faults. A sampling campaign was completed between November 2012 and November 2013, during which data were obtained from 23 different groundwater sites in the fault areas. Two main groups of waters were distinguished: (a) Ca2+-Mg2+-HCO3− facies characterized by poor conductivity and salinity; and (b) saline waters (up to 30 meq/L) rich in Ca2+-Mg2+-SO4-Cl− and with an elevated conductivity (frequently > 1000 μS/cm). In addition, a minor group of saline and warm waters (T > 16.5 °C) was found to be Na+-rich and show moderately high B values (>0.33 ppm), and which mig ht be hosted in aquifers deeper than the two main groups. This group of deep-origin waters is oversaturated in clay minerals and is in equilibrium for Ca-Mg carbonate minerals. X-ray diffraction and scanning and transmission electron microscopy data corroborate the crystallization forecast of authigenic smectite, which appears as thin films coating carbonate fragments. The origin of smectite is related to the fragile strain and thermal–fluid–mineral interactions in fault rocks. Smectite could lubricate carbonate rocks, which favor creep deformation versus seismic slip. This work provides locations where groundwater physico-chemical properties and composition suggest tectonic fault activity. [ABSTRACT FROM AUTHOR]

The central Betic Cordillera, southern Spain, is affected by an uplift related to the NNW–SSE Eurasia‐Nubia convergence and shallow ENE–WSW orthogonal extension accommodated by the extensional system of the Granada Basin. The combination of geophysical, geodetic, and geological data reveals that the southwestern boundary of this extensional system is a seismically active compressional front extending from the W to the SW of the Granada Basin. The near‐field Global Navigation Satellite System data determine NNE–SSW shortening of up to 2 mm/yr of the compressional front in the Zafarraya Polje. In this setting, the normal Ventas de Zafarraya Fault developed as a result of the bending‐moment extension of the Sierra de Alhama antiform and was last reactivated during the 1884 Andalusian earthquake (Mw 6.5). The uplift in the central Betic Cordillera together with the subsidence in the Western Alborán Basin may facilitate a westward to southwestward gravitational collapse through the extensional detachment of the Granada Basin. The heterogeneous crust of the Betic Cordillera would generate the compressional front, which is divided into two sectors: thrusting to the west, and folding associated with buttressing to the south. Our results evidence that basal detachments, linking extensional fault activity with compressional fronts, may determine the activity of local surface structures and the geological hazard in densely populated regions. Plain Language Summary: A combination of geological, geophysical, and geodetic methods is used to understand the evolution in the frontal area of the extensional system of Granada Basin, near the Zafarraya Polje. In particular, this approach improves our knowledge of the Ventas de Zafarraya Fault (VZF) that hosted the 1884 Andalusian earthquake. Seismic data provide information on the distribution of stress and deformation in the region and made it possible to identify a compressional front linked to the extensional system of the Granada Basin. Global Navigation Satellite System (GNSS) data accurately locate the sites of the Zafarraya GNSS network surrounding the VZF, and repeated measurements provide deformation rates of the area that suggests shortening. Thus, we locate the VZF within the former compressional setting. Meanwhile, electrical‐resistivity tomography images sub‐surface structures given its electrical properties and, together with the field geological observations, suggests the extensional behavior of the fault. Therefore, it is considered to be a fold‐related fault formed due to the extension of the outer arc of the Sierra de Alhama antiform. As in the research presented here, a joint interpretation of data from different methods makes it possible to propose active seismic tectonic extensional models in a compressional setting applicable to other regions. Key Points: Shortening up to 2 mm/yr suggests activity of the Ventas de Zafarraya normal Fault simultaneous to foldingThe Sierra de Alhama‐Zafarraya Polje area belongs to a compressional front located to the W and SW of the extensional Granada BasinShallow normal faults may constitute the surface expression of deep main faults developed in a complex crustal compressional setting [ABSTRACT FROM AUTHOR]

This study uses heavy detrital minerals to determine actualistic fluvial and beach sand provenance across the Betic Cordillera (Spain), along the coast from Almeria to Marbella. The Betic Cordillera, primarily composed of metamorphic rocks to the east, supply an assemblage dominated by almandine and graphite, with a longshore dispersal from Almeria to Malaga. Buergerite and hypersthene indicate the provenance of calcalkaline lavas east of Cabo de Gata. The western part of the Betic Cordillera, which comprises the Ronda Peridotite Complex, supplies a chromite and diopside assemblage, with a dispersal from Marbella to Algeciras. Considering these mineralogical suites, the effects of source rock compositions and weathering are evaluated. The heavy mineral species mirror the mineralogy of the source rocks of local outcrops and wider source terranes. The fluvial heavy mineral suites do not differ significantly from those in the beaches except for some unstable species. Unstable species such as olivine, pyroxene, and amphibole do not show evidence of loss because of elevated topography and semiarid climate, which do not affect heavy minerals. This contribution also evaluates the potential of some heavy detrital species as ideal pathfinders in searching for diamonds.

Understanding the crustal fault interaction and connection between earthquakes in areas with slow tectonic deformation, such as Betic Cordillera (South Spain), is challenging. When seismic rates are low and large destructive earthquakes happen less frequently, it is necessary to resort to historical or paleoseismic records. This study investigates the postseismic viscoelastic relaxation mechanism as a potential explanation for the occurrence of three historical earthquakes (IEMSVIII‐IX) in the Eastern Betic Shear Zone during the XVI‐century, all of which occurred within a span of 13 years: 1518 Vera Mw6.2, 1522 Alhama de Almeria Mw6.5, and 1531 Baza Mw6.2 associated with the Palomares, Carboneras, and Baza faults, respectively. The results strongly suggest a sequential stress‐triggering connection between the three events. The northern NS‐oriented section of the Baza fault is found to have experienced a larger positive ΔCFS and, indeed, more prone to rupture in 1531. The study also examines whether the cumulative ΔCFS had influenced the occurrence of further significant earthquakes (≥Mw6.0) in the region. A triggering connection between the cascade and the 1658 Almeria Mw6.2 earthquake is suggested, whereas no indications of similar linkage to the 1674 Lorca Mw6.0 or the 1804 Dalias Mw6.4 events are found. The stress triggering impact of the cascade over nearby active faults is noteworthy. It is expected that this analysis could have future applications for studying other important historical events, and improving seismic hazard analysis in complex fault settings of the Betic Cordillera. Key Points: The occurrence of XVI‐century cascade in the Eastern Betic Shear Zone was encouraged by both coseismic and postseismic Coulomb stress changesOther faults including candidate causative faults for the 1658 Almeria Mw 6.2 earthquake have been loaded following the XVI‐century cascadePostseismic viscoelastic effects on fault interaction should be integrated into fault‐based and time‐dependent seismic hazard assessments [ABSTRACT FROM AUTHOR]

• Abundant record of Macaronichnus segregatis degiberti in a Tortonian package has been studied. • Storm-wave dominated, tide-influenced shoreface/subtidal to offshore transition setting is interpreted. • Possible contemporaneous presence of? M.s. maeandriformis is observed for the first time. • Fluid muds favor the meeting point of ecologically 'incompatible' trace makers. Macaronichnus is a key trace fossil in palaeoceanographic, palaeoclimatic, and petroleum exploration research. Small ichnosubspecies such as Macaronichnus segregatis segregatis , M. s. lineiformins , M. s. maeandriformis and M. s. spiriformis , typically occur in wave-dominated foreshore sands where large M. s. degiberti was never found. The latter shows a wide environmental distribution, occurring in sandy deposits of tidal channels, tidal bar sand sandridges, tidal-flat sand sheets, shorefaces, bioturbated sandy shelf, shelf storm-sheets, shelf sand ridges, and upper slopes. Small M. segregatis and large M. s. degiberti have not been observed to date due the ecological segregation of the tracemakers. An abundant record of large M. s. degiberti in a Tortonian (Late Miocene) mixed carbonate-siliciclastic unit from the Betic Cordillera (southern Spain) has been studied. Occurrence of M. s. degiberti is the result of the interaction of tidal and waves, storm influenced environment determining high-energy conditions and associated palaeoenvironmental parameters as shifting substrates, organic matter availability, and oxygenated pore and bottom-waters. Locally, associated to M. s. degiberti appear small, sinuous traces infilled by light material that were originally assigned to M. s. maeandriformis , and very rare M. s. spiriformis. However, the absence of the typical rim of Macaronichnus avoid a conclusive assignment. The coexistence of both small traces (? M. s. maeandriformis) and large M. s. degiberti is identified in the deposits underlying mudstone layers, revealing the importance of mud deposition during tidal slack water intervals or linked to fluid mud events favouring the co-occurrence of the trace makers of both Macaronichnus ichnosubespecies. This fact would have significant palaeobiological and palaeoecological implications, and could be the first record of both ichnosubspecies in the same intervals. [ABSTRACT FROM AUTHOR]

This work presents the first paleobiogeographical study of the forests of the Sierra del Tablón, one of the northernmost mountain massifs of the Serranía de Ronda (Spain) and the highest point in the province of Seville at 1,129 m a.s.l. The mesological approach is used to analyse the physical characteristics of the mountain massif (geology, geomorphology and climate). Study of past and present vegetation is also addressed, identifying the dominant plant formations and their evolution since the mid-twentieth century, with particular attention to the forest facies representative of the climax stages. Finally, the results of the pedoantracological analysis carried out in the study area are included, which enables us to delve into the dynamics of their vegetation by carrying out two pedological samples. [ABSTRACT FROM AUTHOR]

A hydrochemical and mineral study of groundwaters and damaged rocks from the Tíscar and Larva fault zones (Betic Cordillera, Iberian Peninsula) was carried out in order to (a) describe the physical and chemical properties of the groundwaters; (b) recognize significant locations with deep-origin fluids related to active tectonics; (c) and to describe the water–rock interaction and the neoformation of clay mineral processes and their importance in the seismicity of the faults. A sampling campaign was completed between November 2012 and November 2013, during which data were obtained from 23 different groundwater sites in the fault areas. Two main groups of waters were distinguished: (a) Ca2+-Mg2+-HCO3− facies characterized by poor conductivity and salinity; and (b) saline waters (up to 30 meq/L) rich in Ca2+-Mg2+-SO4-Cl− and with an elevated conductivity (frequently > 1000 μS/cm). In addition, a minor group of saline and warm waters (T > 16.5 °C) was found to be Na+-rich and show moderately high B values (>0.33 ppm), and which mig ht be hosted in aquifers deeper than the two main groups. This group of deep-origin waters is oversaturated in clay minerals and is in equilibrium for Ca-Mg carbonate minerals. X-ray diffraction and scanning and transmission electron microscopy data corroborate the crystallization forecast of authigenic smectite, which appears as thin films coating carbonate fragments. The origin of smectite is related to the fragile strain and thermal–fluid–mineral interactions in fault rocks. Smectite could lubricate carbonate rocks, which favor creep deformation versus seismic slip. This work provides locations where groundwater physico-chemical properties and composition suggest tectonic fault activity.

A new Triassic small marine reptile has been found in the locality of Cehegín (Murcia, Southeastern Spain). The fossil remains mainly comprise moulds of the bones and some osseous fragments still embedded in the rock. These correspond to an articulated sauropterygian, being distinguishable the cervical vertebrae in one rock, while the other rock preserves the middle-inferior part of the body, being differentiated some dorsal, sacral and caudal vertebrae, the ribs, the gastralia, part of one forelimb, part of the hindlimbs and some pelvic elements that can be also intuited. The moulds of dorsal vertebrae, the ribs and the gastralia are overlapped, but it can be distinguished that the ribs are pachiostotic and the gastral ribs are constituted by different components (partite gastral ribs). The features of this reptile permit to refer it to Eosauropterygia. This discovery constitutes the most complete sauropterygian found, to date, in the SouthIberian Palaeomargin of the Tethys, and adds new information about the diversity and palaeogeographical distribution of Sauropterygia in the Middle Triassic, indicating that it was greater than previously believed. [ABSTRACT FROM AUTHOR]

In the western part of the Sierra de los Filabres area, there are fine-grained metamorphic rock bands, showing a field aspect simitar to slates, as previously described in the geological literature of the studied region. They are variable in thickness, from millimeters to tens of meters and appear intercalated in the schist succession. The geochemical resemblance between both types of rocks (major, minor and trace elements), determined by a statistical approach and the comparison of depositional condition indices, points to a similar sedimentary origin of the protolith but different clay content. Mineral facies and illite "crystallinity" indices in the so-called slates indicate that they followed the same metamorphic path and reached the same metamorphic grade than schists. According to compositional zoning detected in micas and garnets present in both lithologies and the P-T conditions deduced from garnets, the mineral nucleation and growth episode of the main mineral paragenesis in these fine-grained schists was more remarkable during the high-pressure event, with a no significant effect of the latter low-pressure–high-temperature episode. In contrast, the coarse-grained schists developed higher size minerals during the low-pressure–high-temperature episode. A differential mylonitization process during the metamorphism is proposed to justify the discrepant field appearance and the contrasting response of both types of metapelitic rocks to the latter metamorphic event. [ABSTRACT FROM AUTHOR]

This work presents the chronology of the Holocene filling of the Guadalentín Tectonic Depression (Murcia, SE Spain) combining 14C and OSL age data. This work studies the sediments and paleosols interbedded in the sedimentary sequence between Totana and Librilla, using as reference the Espuña Karting section (Alhama de Murcia), which has been fully sampled for its geochronological analysis. The entire dated sequences record the last c. 20–19 ka BP, although local basal travertine beds extend back to the Late Pleistocene (30–33 ka). Soil morphology and properties from dated paleosols record different environmental crises in SE Spain, but also a progressive aridification throughout the Holocene. The Chalcolithic Paleosol develops soon after c. 4.6–4.0 BP, nearly coinciding with the start of the Meghalayan stage, evidencing a drastic change from relatively humid to arid conditions, coincident with the crisis of the Copper Age civilizations in Spain. The Bronze Age paleosol also developed under arid but relatively more humid conditions, indicating a more important and longer gap in the sedimentary sequence soon after c. 2.5–2.7 ka BP. This stop in the sedimentation are correlative to the first stages of fluvial incision at basin center locations and the desiccation and fragmentation of the ancient wetlands coinciding with the collapse of the Bronze Age civilizations in SE Spain (Argaric Culture). During the Ibero-Roman Humid Period (IRHP), c. 2.6–1.6 ka BP, the last pedogenic cycle occurred under relatively humid conditions. This preluded the progressive establishment of exorheic fluvial environments as well as a period of paleoseismic activity in the area around 2.0–1.8 ka BP. [ABSTRACT FROM AUTHOR]

High‐resolution microstructural analysis of porphyroblast inclusion trails integrated with Sm‐Nd garnet geochronology has provided new insight into the tectonic history of the Betic‐Rif orogen. Three principal age groups of porphyroblasts are demonstrated with distinctly oriented inclusion‐trails. Inclusion‐trail curvature axes or "FIA" (Foliation Inflexion/Intersection Axes) are shown to represent "fossilized" crenulation axes from which a succession of different crustal shortening directions can be deduced. The regional consistency of microstructural orientations and their geometric relationship with multiple sets of macroscopic folds reveal the composite character of the Gibraltar Arc formed by a superposition of different folding directions and associated lineations. Bulk‐garnet ages of 35–22 Ma obtained from five micaschist samples of the Alpujarride‐Sebtide complex (ASC) and of 35–13 Ma from four micaschists of the Nevado‐Filabride complex (NFC) allow to deduce NNE‐SSW directed shortening in the Late Eocene changing to NW‐SE shortening in the early Oligocene, alternating with suborthogonal NE‐SW shortening during the Miocene. These directions can be related to a major swing in the direction of relative Africa‐Iberia plate‐motion known from kinematic modeling of magnetic seafloor anomalies, and subsequent dynamic interference between plate convergence and suborthogonal "tectonic escape" of the Alboran Domain. Coupled to previously established P‐T‐t paths, the new garnet ages support a common tectono‐metamorphic evolution of the ASC and NFC as laterally equivalent orogenic domains until, in the Miocene, the second became re‐buried under the first. Plain Language Summary: A 3D microstructural analysis of tectonic foliations preserved within garnet porphyroblasts combined with radiometric dating of these crystals has allowed reconstruction of a complex tectonic history experienced by the Betic‐Rif orogen, the strongly curved mountain belt connecting southern Spain and Morocco. Multiple porphyroblast age groups can be linked to differently oriented microfolds preserved within these metamorphic crystals. The specific ages and orientations of these microstructures measured using conventional thin sections and X‐ray tomography can be matched to known changes in the direction of convergence of the African and Iberian plates, thus demonstrating a powerful new tool for reconstructing past plate motions. Key Points: Three sets of microfolds (Foliation Inflexion/Intersection Axis, FIA) preserved within garnet porphyroblasts of the Betic‐Rif orogen record changes in crustal shortening directionNew Sm‐Nd garnet ages reveal Eocene to Miocene tectonism in the Nevado‐Filabride complexIntegration of FIA data with garnet geochronology shown powerful tool for reconstructing past plate motions [ABSTRACT FROM AUTHOR]

In this research, we conducted the first P-wave tomographic imaging of 3-D azimuthal anisotropy of the Granada Basin (Betic Cordillera, Spain) introducing recent advances in the application of this method, thanks to abundant, high-quality data sets recorded by a dense seismic network deployed in the study area during the Atarfe-Santa Fe seismic series (2020−2021). We also determined high-resolution P- and S- wave tomography for 3-D isotropy of the study area down to 14 km depth and then the three-dimensional distributions of Poisson's ratio (σ). The result for the uppermost crust reveals the lower velocities associated with the predominantly Neogene-Quaternary sediments in the Basin. During the Atarfe-Santa Fe seismic series there were five earthquakes with a magnitude of over 4.1. In the source areas of the first of these earthquakes, significant variations were detected in P-velocities and high Poisson's ratios. This suggests that fluids might be involved in the nucleation and development of the seismic sequence. The fast polarization directions (NE-SW) in the central study area are mostly parallel to the Cadiz-Alicante fault system and almost perpendicular to the NW-SE fault plane directions obtained from the focal mechanism solutions for the earthquakes with the largest magnitudes, which present a clearly NE-SW extensional model. At the end of the middle Miocene, the Cadiz-Alicante fault system was practically immobilized, and an approximate NNW-SSE compression with a perpendicular extension, which was strongly pronounced in the Granada basin, was established. This extension is now active. Our results could therefore be suggesting that extension tectonics is the dominant effect in the upper crustal depth, as reflected by a significant NE-SW Fast Velocity Direction (FVD). Another possibility is that the FVD may have continued unchanged since the end of the middle Miocene due to the control exerted by the Cadiz-Alicante fault system, indicating structure-induced crustal anisotropy. • The results provide unique constraints on the seismic structure in the Granada Basin (Betic cordillera, Spain). • P-wave anisotropy tomography is a powerful tool for the study of active tectonic regions. • Lower seismic velocities are associated with the predominantly Neogene-Quaternary sediments in the Granada Basin (Betic cordillera, Spain). • Fluids might be involved in the nucleation and development of seismic sequences. • High Poisson's ratios and strong seismic velocity contrasts suggests that the active faults in this area are mechanically weak and unstable. [ABSTRACT FROM AUTHOR]

Fault barriers are key structures for studying seismic hazard in regions of intense brittle deformation. The interaction between fault sets affects their seismogenic behavior, if some of them act as barriers. The Granada Basin, in the Betic Cordillera, is a region affected by shallow brittle deformation, as it was the scenario for the recent Granada 2021 seismic sequence. This seismicity presented a swarm behavior at the beginning of the sequence, followed by mainshock‐aftershock features. Geological and gravity data presented here reveal that the basement is affected by two sets of NW‐SE and NE‐SW normal faults and intensely deformed by vertical NW‐SE joints. Improved relocation of the Granada 2021 seismicity reveals a confined chimney‐shape seismicity caused by the activity of a 2 km long NW‐SE normal fault segment. The confinement of the sequence is associated with the NE‐SW fault set acting as a barrier that restricts the rupture area, limiting the maximum magnitude, and favoring the recurrence of events with smaller magnitude. The chimney‐shape of the seismic sequence suggests that the deformation is propagated vertically to the surface, facilitated by preexisting fractures. The shallow extensional deformation during the uplift of the central Betic Cordillera drove the activity of the local structures obliquely to the regional extensional trends, as evidenced by the seismic sequence. This multidisciplinary study improves the knowledge on the origin of the Granada Basin and underlies the important role of preexisting fractures on fault segmentation and seismic propagation, decreasing the seismic potential of this area. Key Points: The Granada 2021 seismicity is related to the activity of a 2 km NW‐SE normal fault segment bounded by oblique faults acting as barriersThe confined seismic activity extended vertically due to preexisting intense brittle deformation of the basementThe seismic barriers responsible for a swarm evolving to mainshock‐aftershock behavior decreased the seismic potential by some extent [ABSTRACT FROM AUTHOR]

Neogene sedimentary rocks cover extensive areas of the Cabo de Gata-Níjar UNESCO Global Geopark (Almería, SE Spain) although most of the outcropping rocks are Miocene volcanics. The post-volcanic sedimentary rocks include three successive Messinian coral reef units. The lower reefs consist of coral patches of varying dimensions comprising Porites and Tarbellastraea, which grew on carbonate ramps. The second unit is Porites fringing reefs that prograded from shorelines. These two lower units, early Messinian in age, were subaerially exposed and eroded during a relative sea-level drawdown, probably coeval with the Mediterranean Messinian salinity crisis. The last, late Messinian reef unit onlaps the erosion surface and consist of small Porites patches that grew dispersed in oolitic shoals together with microbial carbonates. These low-diversity reefs are the last zooxanthellate coral reefs in the Mediterranean basin and constitute the endpoint of decreasing coral diversity in the region during the Miocene due to disconnection from the Indian Ocean and global cooling. The good exposures and accessibility of these reefs in the arid landscape of the Geopark make them valuable sites for practical training in geology and paleontology at different levels and reference sites for geotourism.

Widespread overprinting of early high‐pressure/low‐temperature (HP/LT) subduction stages due to subsequent collisional or late‐orogenic tectono‐metamorphic events is a common feature affecting the interpretation of geochronologic data from HP/LT orogens. The Betic‐Rif orogen is exemplary in this connection as a great majority of published radiometric ages are found to cluster around 20 Ma. This clustering is commonly interpreted as reflecting a short, yet complex, succession of tectono‐metamorphic events spanning only over a few Myr, including back‐arc extension and overthrusting of the Internal Zones on the External Zones. An alternative explanation consists in the poor preservation of a much earlier HP/LT metamorphic event, presumably Eocene, coeval with subduction and crustal thickening in the Internal Zones, and particularly the Alpujárride Complex. However, this age is vividly debated due to widespread resetting by the Early Miocene HT/LP overprint. In this study, we provide new 40Ar/39Ar evidence from white micas selected along an E‐W section of the Internal Betics, from the central to the eastern Alpujárride Complex. Our new data show (a) that exceptionally well‐preserved HP/LT parageneses in this unit retain a well‐defined Eocene age around 38 Ma, and (b) that widespread 20 Ma ages recorded all along the section correspond to a regional stage of exhumation, coeval with a major change in the kinematics of back‐arc extension. Our study provides conclusive evidence that 40Ar/39Ar dating of carefully targeted HP/LT associations can overcome the problem of extensive late‐orogenic overprinting, testifying for an Eocene HP event around 38 Ma in the Betic‐Rif orogen. Key Points: High‐pressure/low‐temperature parageneses, related to the M1 conditions, in the Alpujárride Complex dated at 38 Ma by 40Ar/39Ar of white micasLater retrograde micas yield a 20 Ma spike extensively recorded throughout the Betic Cordillera, and corresponds to a regional exhumationEn‐masse isothermal decompression forced the Ar‐white mica system into the open‐system P‐T field producing a resetting of 40Ar/39Ar ages [ABSTRACT FROM AUTHOR]

Understanding active tectonics and seismicity in extensional settings requires the analysis of high‐angle normal faults (HANFs) and the transfer of deformation at depth. The debate surrounds the role of low‐angle normal faults (LANFs) in triggering high magnitude earthquakes. The central Betic Cordillera is an active seismic zone affected by the NNW‐SSE Eurasia‐Nubia convergence and orthogonal extension. The seismicity and present‐day stress determined by earthquake focal mechanisms reveals the activity of a NE‐SW extensional system in the shallowest 12 km of the Granada Basin. The structure of the sedimentary infill, as derived by geological field and gravimetric techniques, suggests the formation of a half‐graben tilted to the N‐NE. Seismologic data suggest the activity of HANFs above 6–7 km depth and a LANF zone around 6–12 km depth, with related earthquakes of up to Mw 4.0 and 20° to 30° fault dips. High‐precision leveling lines highlight the importance of the Granada Fault in the system, with average vertical displacement rates of 0.35–1.1 mm/yr. These data suggest creep fault behavior at the surface and increased seismicity at depth. The upper crustal extension in the collisional Betic Cordillera is accommodated by a top‐to‐the‐WSW extensional detachment related to westward motion and rollback in the Gibraltar Arc and the gravitational collapse of the cordillera, in a framework of NNW‐SSE shortening. This comprehensive study draws a new scenario that advances understanding of relationships between HANFs and LANFs. Key Points: Gravimetric data highlight the geometry of the sedimentary infill of the Granada Basin, which constitutes a half‐graben tilted to the N‐NEGranada Basin's high‐angle normal faults might be linked at depth to an active low‐angle extensional deformation zoneThe active Granada Fault zone shows low‐magnitude seismicity and a current average vertical rate that varies from 0.4 to 1.1 mm/yr [ABSTRACT FROM AUTHOR]

Land-use decisions in relation to seismic-induced landslide hazard are usually made through the preparation of hazard maps. The rigid-block method is probably the most used for this purpose. Under this method, Newmark displacement is computed for each slope unit and this displacement is used as a guide for establishing categories of hazard. At present, most relations used for computing Newmark displacement are established from moderate-to-high magnitude earthquakes (Mw ≥ 6.5). This data article provides Newmark displacements computed from accelerograms recorded in the Betic Cordillera for low-to-moderate magnitude earthquakes (Mw = 3.5–6.3). Records come from the Spanish Strong Ground Motion database (Instituto Geográfico Nacional). Newmark displacements were computed focusing on yield accelerations frequently recorded in such scenarios (0.02, 0.03, 0.04, 0.05, 0.06, 0.08 and 0.10), although higher accelerations were also considered (0.125, 0.15, 0.20, 0.25 and 0.30 g's). These data are useful for the study of the hazard in seismic scenarios of low-to-moderate magnitude, very frequent in practice. These data have been used in the study by Delgado et al. [1].

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This research explores the Messinian record in a western Mediterranean basin at the eastern end of the Betic Cordillera (the Garruchal section, southern sector of the Bajo Segura basin). Sedimentary facies development and foraminiferal assemblages were used as palaeoenvironmental proxies to characterize the palaeoceanographic evolution of the basin's progressive restriction. Therefore, a succession of palaeoenvironmental phases can be established as follows. The "start phase" (until ~ 6.72 Ma) records the first ecological evidence of the restriction, evidenced by the sudden appearance of common benthic stress markers. The "amplification phase" of the restriction (up to ~ 6.35 Ma) marks a progressive increase in low bottom oxygen levels related to water-mass stratification in the evolution from upper epibathyal to outer shelf environments. The "consolidation phase" (until the intra-Messinian discontinuity ~ shortly after 6.03 Ma) records basin shallowing (from outer to inner shelf environments) in a context of a restricted basin. And lastly, the "climax phase" (until the end-Messinian discontinuity) records coastal sedimentation (marine coastal lagoon and sandy beaches). The findings of this research reveal that the Garruchal section is a good illustration of the sedimentary and palaeoenvironmental response of the peripheral basins to the progressive restriction of the Mediterranean before the Messinian Salinity Crisis. Finally, since it is widely accepted that the Mediterranean marine restriction has been developed in a stepwise mode, we here propose to establish the following terms for implementation at Mediterranean regional level: "start," "amplification," and "consolidation" phases, which finally led to the "climax" phase, that is, the Messinian Salinity Crisis stricto sensu. [ABSTRACT FROM AUTHOR]

Sauropterygian vertebrate remains from the Ladinian (Middle Triassic) of the proximity of Calasparra (Murcia, Spain) are described here. They represent the first documented Triassic vertebrate remains found in the Province of Murcia, and the first in the Subbetic domain of the Betic Cordillera (Southeastern Spain). These new remains consist of incomplete vertebrae, some fragmented neural spine apophyses, fragments of transverse processes, a partial thoracic vertebrae mould and one isolated thoracic vertebral centrum, seemingly of a single specimen. Their features permit to refer them to the suborder Eusauropterygia. These fossils have been found in the middle part of the upper member of the Cehegín Formation. The biostratigraphical framework of the Cehegín Formation consists of a relatively abundant fossil content that allowed its attribution to the uppermost Fassanian (Lower Ladinian). The sedimentary features and the palaeontological content of the site are typical of an epicontinental platform. [ABSTRACT FROM AUTHOR]

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In this work we present for the first time a petrological-geochemical and genetic study of the Sierra de Baza ophiolites, which represent one of the ophiolitic occurrences of the Betic Cordillera (Southern Spain). They are composed of ultramafic, mafic and sedimentary rocks, largely affected both by ocean floor and polyphasic metamorphism during the Alpine orogeny. Ultramafic rocks are serpentinized lherzolites and harzburgites, whereas the metabasites are meta-gabbros and meta-basalts. On the whole, Sierra de Baza ophiolites show striking geochemical similarities with those from other Betic occurrences, as well as with other Tethyan ophiolites of the Western Mediterranean (Calabria, Internal and External Ligurides, Platta, Corsica and Western Alps). In particular, metabasites show petrological and geochemical features similar to the E-MORB magmatism of the Atlantic Ridge between 45 and 63ºN generated under ultra-slow spreading ridge conditions. This process originated a strip of few hundreds km of ocean floor at the western end of the Tethys, located SE of the Iberian-European margin during the Mesozoic. The inversion of the stress regime in the European-Iberian and African geodynamics, starting from the Late-Middle Cretaceous, caused subduction and metamorphism in the eclogite facies of oceanic slices that were partially exhumed on the continental margin, forming the Betic Ophiolites. These ophiolites were disarticulated and dismembered as a result of the shift towards SW of the Alboran continental block, progressively separated from the AlKaPeCa (Alboran, Kabilias, Peloritani, Calabria) microplate, finally occupying their current position in the Betic Internal Zones. [ABSTRACT FROM AUTHOR]

The long-term Pressure-Temperature-time-deformation (P-T-t-d) evolution of the internal zones of orogens results from complex interactions between the subducting lithosphere, the overriding plate and the intervening asthenosphere. 2-D numerical models successfully reproduce natural P-T-t-d paths, but most orogens are non-cylindrical and the situation is far more complex due to 3-D pre-orogenic inheritance and 3-D subduction dynamics. The Mediterranean orogens are intrinsically non-cylindrical. Their 3-D geometry results from the complex shape of the Eurasian and African margins before convergence and from the dynamics of slab retreat and tearing leading to strongly arcuate belts. More than many other segments, the Betic-Rif belt is archetypal of this behavior. A synthesis of the tectonometamorphic evolution of the Internal Zones, also based on recent findings by our group in the framework of the Orogen Project (Alboran domain, including the Alpujárride-Sebtide and Nevado-Filábride complexes) shows the relations in space and time between tectonic and P-T evolutions. The reinterpretation of the contact between peridotite massifs and Mesozoic sediments as an extensional detachment leads to a discussion of the geodynamic setting and timing of mantle exhumation. Based on new 40Ar/39Ar ages in the Alpujárride-Sebtide complex and a discussion of published ages in the Nevado-Filábride complex, we conclude that the age of the HP-LT metamorphism is Eocene in all complexes. A first-order observation is the contrast between the well-preserved Eocene HP-LT blueschists-facies rocks of the eastern Alpujárride-Sebtide Complex and the younger HT-LP conditions reaching partial melting recorded in the Western Alpujárride. We propose a model where the large longitudinal variations in the P-T evolution are mainly due to (i) differences in the timing of subduction and exhumation, (ii) the nature of the subducting lithosphere and (iii) a major change in subduction dynamics at ∼20 Ma associated with a slab-tearing event. The clustering of radiometric ages obtained with different methods around 20 Ma results from a regional exhumation episode coeval with slab tearing, westward migration of the trench, back-arc extension and thrusting of the whole orogen onto the African and Iberian margins.

The present-day tectonic setting of the Western Mediterranean region, from the Pyrénées to the Betics and from the Alps to the Atlas, results from a complex 3-D geodynamic evolution involving the interactions between the Africa, Eurasia and Iberia plates and asthenospheric mantle dynamics underneath. In this paper, we review the main tectonic events recorded in this region since the Early Cretaceous and discuss the respective effects of far-field and near-field contributions, in order to unravel the origin of forces controlling crustal deformation. The respective contributions of mantle-scale, plate-scale and local processes in the succession of tectonic stages are discussed. Three periods can be distinguished: (1) the first period (Tethyan Tectonics), from 110 to 35 Ma, spans the main evolution of the Pyrenean orogen and the early evolution of the Betics, from rifting to maximum shortening. The rifting between Iberia and Europe and the subsequent progressive formation of new compressional plate boundaries in the Pyrénées and the Betics, as well as the compression recorded all the way to the North Sea, are placed in the large-scale framework of the African and Eurasian plates carried by large-scale mantle convection; (2) the second period (Mediterranean Tectonics), from 32 to 8 Ma, corresponds to a first-order change in subduction dynamics. It is most typically Mediterranean with a dominant contribution of slab retreat and associated mantle flow in crustal deformation. Mountain building and back-arc basin opening are controlled by retreating and tearing slabs and associated mantle flow at depth. The 3-D interactions between the different pieces of retreating slabs are complex and the crust accommodates the mantle flow underneath in various ways, including the formation of metamorphic core complexes and transfer fault zones; (3) the third period (Late-Mediterranean Tectonics) runs from 8 Ma to the Present. It corresponds to a new drastic change in the tectonic regime characterized by the resumption of N-S compression along the southern plate boundary and a propagation of compression toward the north. The respective effects of stress transmission through the lithospheric stress-guide and lithosphere-asthenosphere interactions are discussed throughout this period.

AMS and structural analysis are here applied to study the deformed zone associated with a large-scale, active normal fault in the central Betic Cordillera (Spain), namely the Baza fault system, to determine: i) the kinematics of structures and their relation with fault zone architecture and segmentation degree, ii) the correlation between deformational structures and the different types of magnetic fabrics and iii) the evolution of magnetic fabrics patterns, from sedimentary to shear-related, associated with normal faults. Five outcrops (969 samples) were analysed along the fault trace, which shows different degrees of segmentation along strike and strong localization of deformation along narrow fault zones. A first, main set of magnetic fabric data corroborates the normal kinematics of the Baza fault, showing magnetic lineations parallel to the dip-slip, transport direction. A second, secondary set of magnetic lineations, is parallel to the intersection lineation, and can be related to less intense deformation in the fault rocks. Furthermore, a detailed study (523 samples) of a trench excavated across the fault zone, where two fault splays tend to coalesce in a linkage relay zone indicates that i) lithology and distance to fault planes are two factors that control the development of extension-related magnetic fabrics in weakly deformed sediments, ii) the development of shear-related fabrics in fault zones entails the mechanical rotation of minerals, iii) different orientation of magnetic lineations are related to different intensity of bulk deformation and iv) magnetic lineation is useful to define local deviations of deformation axes produced by changes in the local extension direction (from fault-perpendicular to fault-parallel extension) in the linkage zone between adjacent fault splays. • First AMS study applied to large-scale, pure normal fault zones in brittle deformation contexts. • Characterization of different fault zone architectures along the fault system. • Changes and evolution of AMS ellipsoid related to different tectonic overprint. • Stress and strain perturbation within relay ramps revealed by AMS data. • Contribution to define the overall kinematics of the seismogenic Baza Fault System. [ABSTRACT FROM AUTHOR]

The poorly-known species Baculites Renevieri Ooster, 1860 is revised using the type material from Switzerland and new conspecific specimens collected in deposits from Mallorca and the Betic Cordillera (Western Mediterranean), listing all the previous mentions of the species. The uniqueness of its ornamentation pattern and shell shape compared to other coeval ammonoid faunas demands for the description of Glaucoceras gen. nov. to contain this species. In addition, a thorough comparison of Glaucoceras renevieri to other morphologically reminiscent genera or species is provided. This new set of data allows to improve the knowledge of one of the many phylogenetic lines of heteromorphic ammonites that diversified over the latest Hauterivian in the Mediterranean Province, also providing hints about the timing of those radiation events. This aspect is preliminary explored using data on other coeval heteromorphic ammonoid groups from the literature and new finds, concluding that there occurred two main radiation events of heteromorphic ammonites at the latest Hauterivian, most likely related to environmentally stressful episodes, specifically, transgressive events. • The genus Glaucoceras gen. nov. is described to include the poorly-known species Baculites Renevieri Ooster, 1860. • The stratigraphic range of Glaucoceras renevieri spans from the B. binelli Sz to the P. mortilleti Sz of the latest Hauterivian (Early Cretaceous). • The origination of this genus seems to be related to a transgressive maximum that occurred at the B. binelli – B. krenkeli Szos (late Hauterivian). • Two transgressive events in the latest Hauterivian are interpreted as the triggers of the diversification of other heteromorphic ammonoids. [ABSTRACT FROM AUTHOR]

U-Pb dating on inherited detrital zircons has been applied to obtain the probable maximum age of deposition of the detrital protolith of the Nevado-Filábride complex (Betic Cordillera, Spain). Five of eight samples correspond to the lower part of the lithologic sequence of this complex, where radiometric dating of metasediments has not been presented till the present. The youngest age populations in the majority of samples are Carboniferous. The estimation of the maximum age of deposition in the lower and upper units is 349.1 ± 1.6 and 334.6 ± 2.9 Ma, respectively. In addition, samples show common age populations at ca. 490-630 and ca. 910-1010 Ma. Observations agree with the Carboniferous to early Permian U-Pb ages previously obtained in orthogneisses levels which are situated in the upper part of the complex. Combination of the minimum age of deposition deducible from the orthogneisses studies and the maximum ages of deposition obtained from the detrital zircons of this work, allow establishing the deposition of de studied lithological succession comprised between ca. 282 and 349 Ma or a shorter period. [ABSTRACT FROM AUTHOR]

This work reviews the 1863 Huércal-Overa earthquake (VI-VII EMS) based on the environmental seismic intensity scale (ESI-07) and oriented archaeoseismological building damage. The performed analysis identifies 23 environmental effects (EEEs) and 11 archaeoseismological effects (EAEs), completing a total of 34 intensity data-points within the intensity zone ≥ VI EMS. The new ESI intensity data quintuplicate the previous intensity data-points ≥ VI EMS (five localities) for this event. Sixteen of the identified EEEs indicate the occurrence of intensity VII-VIII within the Almanzora valley, south of Huércal-Overa, over an area of ca. 12–15 km2. Anomalies in water bodies, slope movements, hydrogeological anomalies, ground cracking, and other effects (gas emissions, tree shaking) are the more diagnostic EEEs—with one of them indicating a local maximum intensity of VIII-IX ESI-07 (Alboraija lake). Environmental earthquake damage of intensity ≥ VI covers an area of c. 100 km2, compatible with a VIII ESI intensity event. The spatial distribution of EEEs and EAEs indicates that the zone of Almanzora River Gorge, which was depopulated during the earthquake epoch, was the epicentral area, and compatible with seismotectonic data from active shallow blind thrusting beneath the Almagro Range. The use of ESI data in nearly unpopulated areas help to fill gaps between damaged localities (EMS data) multiplying intensity data-points, providing a better definition of the intensity zones and offering a geological basis to look for suspect seismic sources.