The Late Cenozoic landscape development in the

Geomorphology 327 (2019) 456–471

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Geomorphology journal homepage: www.elsevier.com/locate/geomorph

The Late Cenozoic landscape development in the westernmost Mediterranean (southern Spain) Antonio Guerra-Merchán a,⁎, Francisco Serrano a, José Manuel García-Aguilar a, Carlos Sanz de Galdeano b, José Eugenio Ortiz c, Trinidad Torres c, Yolanda Sánchez-Palencia c a b c

Dpto. Ecología y Geología, Universidad de Málaga, Campus de Teatinos, 29071 Málaga, Spain Instituto Andaluz de Ciencias de la Tierra (CSIC-Universidad de Granada), Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain Laboratorio de Estratigrafía Biomolecular, Escuela Técnica Superior de Ingenieros de Minas y Energía, Universidad Politécnica de Madrid, Spain

a r t i c l e

i n f o

Article history: Received 7 February 2018 Received in revised form 30 October 2018 Accepted 11 November 2018 Available online 23 November 2018 Keywords: Geomorphic evolution Abrasion platforms Alluvial fans Travertines Late Miocene-Quaternary Betic Cordillera (Costa del Sol Malaga)

a b s t r a c t The terrains of the Western Costa del Sol in the westernmost Mediterranean represent an outstanding example of the influence of major tectonic and climatic factors in the development of the landscape. This region belongs to the Alboran domain, which is a small continental lithosphere fragment embedded between the large Eurasian and African plates. The territory between Malaga and Marbella is composed mainly of the Sierra de Mijas and three adjacent subsidence areas: Malaga, Torremolinos, and Fuengirola basins. From the late Miocene, dip-faults of approximate directions N-S, NE-SW and NW-SE limited the Sierra de Mijas with respect to the adjacent subsidence areas and have marked the main features of the coastal morphology. Since then, the Sierra underwent mainly erosive processes linked to strong uplifting, while the surrounding basins were subjected to alternate stages of sedimentation and erosion. Thus, the paleogeographic and geomorphological evolution has been driven both by the regional tectonics and by significant base-level changes ranging from the spectacular Messinian low-stand to the catastrophic overflow at Gibraltar, followed by the global Late Tertiary and Quaternary sea-level changes. In the mountain relief, three different erosive leveling surfaces have been recognized, which developed in a staggered sequence during the Miocene, and are currently fragmented by tectonics at different elevations. The first two leveling surfaces, continental in origin, were carved during the Middle Miocene pro-part. The late one, correlating with Upper Miocene marine deposits from the Malaga basin, appears to correspond partially to an abrasion platform developed during the highstand of the late Tortonian. The strong incision of the fluvial network, especially due to the low sea-level during the Messinian salinity crisis, but also to the tectonic rise of the Sierra, has largely eroded these surfaces, which can be recognized only in narrow inter-fluvial areas. The noteworthy marine transgression in the Miocene-Pliocene transition reached the edge of the Sierra de Mijas, developing both a broad marine abrasion platform around it and the main stage of sedimentary filling in the Malaga basin. Tectonics combined with sea-level changes influenced the formation of a lower, second abrasion platform in the Torremolinos sector and along the S edge of the Sierra, showing continuity with the late Zanclean marine deposits in the Torremolinos and Fuengirola areas. During most of the late Pliocene and the Gelasian, the region remained emerged and subjected to erosion. Conversely, climate-eustatic changes throughout the Pleistocene and Holocene led to the development of three major generations of progradant alluvial fans interrupted by stages of erosion and incision of the fluvial network. In parallel, up to five episodes of travertine build-up occurred, usually coinciding with the humid and warm, odd-numbered isotopic stages. © 2018 Elsevier B.V. All rights reserved.

1. Introduction

⁎ Corresponding author. E-mail addresses: [email protected] (A. Guerra-Merchán), [email protected] (F. Serrano), [email protected] (J.M. García-Aguilar), [email protected] (C. Sanz de Galdeano), [email protected] (J.E. Ortiz), [email protected] (T. Torres), [email protected] (Y. Sánchez-Palencia).

https://doi.org/10.1016/j.geomorph.2018.11.008 0169-555X/© 2018 Elsevier B.V. All rights reserved.

The terrain of the W Costa del Sol between Malaga and Marbella belongs to the Betic Internal Zone, an alpine region that has undergone deformation and metamorphism since the end of the Cretaceous. The tectonogenesis in the middle Oligocene (Serrano et al. 2006) led to the nappe stacking of the different paleogeographic domains (Nevado-Filabride, Alpujarride and Malaguide, from bottom to top).

A. Guerra-Merchán et al. / Geomorphology 327 (2019) 456–471

At a later stage (late Oligocene-early Miocene) the approach and collision between Internal and External Betic Zones occurred in parallel with the closure of the Maghrebian Flysch Basin, resulting in the Betic-Rifain general structuration in the Gibraltar Arc (Andrieux et al. 1971; Durand-Delga and Fontboté 1980; Martín-Algarra 1987; Sanz de Galdeano 1990, and references therein). The main present-day geomorphological features of the Betic Cordillera formed from the late Miocene onward (Lhenaff 1981; Braga et al. 2003; Sanz de Galdeano and Alfaro 2004). During this time, the Betics were subject to a roughly N-S compression (varying between NNE-SSW and NNW-SSE, according to sectors and time) linked to the convergence of the African and European plates (Sanz de Galdeano 1990; Sanz de Galdeano and Vera 1992; Galindo-Zaldívar et al. 1999). In this tectonic context, NW-SE and NE-SW strike-slip faults played a major role in the segmentation of the Cordillera by delimiting the mountain fronts and the subsidence basins (Sanz de Galdeano 1983, 1990; Boccaletti et al. 1987; Montenat 1990; Lonergan and White 1997, and references therein). Also, E-W transcurrent faults that operated in the Internal-External Zone conjunction remained active with varying movements. Some of the previous faults acted with significant vertical movements mostly throughout the Early Pliocene, favored either by a perpendicular extension to the main direction of compression or by relaxation of the compressive framework (Sanz de Galdeano 1983; Sanz de Galdeano and Vera 1992; Rodríguez-Fernández and Sanz de Galdeano 2006; Guerra-Merchán et al. 2014). In addition, sea-level changes also played a highly significant role, especially in relation to the Messinian Salinity Crisis and the reestablishment of the normal marine conditions in the Mediterranean at the beginning of the Pliocene. Thus, some areas were flooded or emerged through time and the base-level changes of the rivers triggered erosional or depositional events. Data on these processes have been provided by Harvey (1984, 1987, 2002), Silva et al. (1992), Calvache and Viseras (1997), Harvey et al. (1999), Mather (2000), and Schoorl and Veldkamp (2003) among others.

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Sierra de Mijas, being the most noteworthy orographic component in the study area (Figs. 1, 2), clearly shows the above-mentioned effects. On the one hand, their edges are predominantly delimited by E-W oriented faults that acted with transcurrent displacements during the Early-Middle Miocene and also by the NE-SW and NW-SE faults that developed during the Late Miocene (Tubía 1985; Sanz de Galdeano and López-Garrido 1991; Andreo and Sanz de Galdeano 1994; Serrano and Guerra-Merchán 2004). Both faulting systems operated with significant vertical movements from the Pliocene, so limiting subsidence basins in Malaga, Fuengirola and Torremolinos sectors (Figs. 1, 2). On the other hand, the significant base-level changes in the Mediterranean, as a consequence of the Messinian Salinity Crisis and the later reflooding due to the opening of the Strait of Gibraltar at the beginning of the Pliocene, proved fundamental in the modeling of the region. Finally, the Quaternary climate cycles are also reflected in the landscape of the region by the development of alluvial fans and travertine build-ups, whose generation phases alternated with stages of prevailing erosion. In previous work on the study area, Lhenaff (1981) described the most remarkable geomorphological aspects, while Tubía (1985) and Andreo and Sanz de Galdeano (1994) studied the main features of the geological structure, and Durán et al. (1988) and Durán (1996) dated different travertine formations developed on the edges of the Sierra de Mijas. Rodríguez-Vidal et al. (2007) described the morpho-sedimentary features of the foothills of the E Sierra de Mijas in the Torremolinos sector. Insua-Arévalo (2008) and InsuaArévalo et al. (2012) described the alluvial fans between Alhaurín el Grande and Alhaurín de la Torre, distinguishing three stages of evolution of the alluvial system. Elez et al. (2016) described the geomorphological features driven by the Messinian Salinity Crisis in an adjacent region located to the north of the study area, and Guerra-Merchán et al. (2018) have made a detailed study of all the travertine build-ups in the Sierra de Mijas and Coín surroundings, emphasizing their multi-phase nature.

Fig. 1. A: Location of the study area in the geologic context of the Betic Cordillera. 1. Alpujarride Complex; 2. Malaguide Complex; 3. Flysch of the Campo de Gibraltar units; 4. Upper Tortonian deposits; 5. Pliocene-Quaternary deposits.

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Fig. 2. Geologic map of the studied region. 1. Marbles (Alpujarride); 2. Metapelites (Alpujarride); 3. Peridotites (Alpujarride); 4. Malaguide Complex; 5. Flysch of the Campo de Gibraltar units; 6. Tortonian; 7. Pl-2 unit; 8. Pl-3 unit; 9. First generation of alluvial fans (AFG-1); 10. Second-generation alluvial fans (AFG-2); 11. Third-generation alluvial fans (AFG-3); 12. Travertines; 13. Recent fluvial deposits; 14. Faults; 15. Thrusts. AG: Alhaurín el Grande; AT: Alhaurín de la Torre; AF: Arenales fault; ACF: Acebuchal fault; APF: Abarcuza-Palomas fault; BF: Benalmádena fault; PP: Puerto de los Pescadores; SA: Sierra de los Ángeles.

The present work deals with the analysis and chronology of the morphotectonic traits and landforms that make up the territory of the western Costa del Sol between Malaga and Marbella (Sierra de Mijas and adjacent depressions), evaluating the influence exerted by tectonic activity, climatic changes, and sea-level variations. The main goal is to help unravel the regional geomorphological evolution from the late Miocene to the present in an area of the western Mediterranean, where major events such as the Messinian Salinity Crisis and the subsequent re-flooding of the Mediterranean Sea, acting in combination with the local tectonics, have clearly left an imprint on the landscape. 2. Geologic setting and stratigraphic record The landscape of the western Costa del Sol between Malaga and Marbella is formed mainly by the Sierra de Mijas and three adjacent subsidence areas: Malaga basin to the N, Torremolinos sector to the E, and Fuengirola basin to the S (Fig. 1). To the W, Sierra de Mijas connects with other mountainous areas such as Sierra Alpujata, Sierra Blanca of Coín, and Sierra Negra (Fig. 2). Sierra de Mijas is made up mainly of Triassic marbles of the Alpujarride complex (Internal Betic Zone) where a lower member, 300 m of clear massive marbles, can be distinguished together with an upper member of 300 m of banded blue marbles with intercalations of schists (Sanz de Galdeano 1997). In the SW sector a narrow band crops out (100–500 m wide and 400 m thick) with migmatites, gneisses, and schists. To the S, above this band, an important outcrop of peridotites is situated, and, occupying the highest position in the tectonic stacking, the Malaguide complex is made up mainly of Paleozoic rocks (shales, phyllites, graywackes, and “calizas alabeadas”) and locally Triassic rocks (conglomerates, sands, and clays). The sedimentary filling from the late Miocene to the present displays significant differences in the three subsidence areas mentioned above. Discontinuous deposition in the Malaga basin ranges from the upper Tortonian to Quaternary. Locally, on the NW edge, Oligocenelower Miocene deposits also crop out, these correlating with the

intra-orogenic “Ciudad Granada” and “Viñuela” formations (Sanz de Galdeano et al. 1993; Serrano et al. 1995). The upper Tortonian deposits (200–300 m thick) consist of conglomerates, sands, and calcarenites deposited in a shallow marine environment characterized by fan deltas, beaches, sea cliffs, and narrow platforms (Serrano 1979). Uppermost Messinian deposits characterizing the Lago-Mare event crop out along the N edge of the Malaga basin (Guerra-Merchán et al. 2010; Serrano and Guerra-Merchán 2014). Lower Pliocene sedimentation represents the main filling of the Malaga basin. Guerra-Merchán et al. (2000, 2014) have differentiated three sedimentary units called Pl-1, Pl-2, and Pl-3, separated by stratigraphic discontinuities. The lowermost Zanclean PL-1 deposits (MPL1 zone by Cita 1975) represent the first fully marine deposition in the area after the opening of the Strait of Gibraltar at the beginning the Pliocene and, as the Lago-Mare deposits, its outcrops are restricted to the N edge of the basin. The PL-2 unit (zone MPL-2 de G. margaritae, lower Zanclean) crops out throughout the entire basin, reaching over 500 m in thickness in the area between the sierras of Mijas and Cártama. On the edges, this unit consists of deltaic and littoral conglomerates, changing distally to clays and marls rich in benthic and planktonic foraminifers. The regressive upper part consists of shallow marine sands and locally (Alhaurín el Grande) black clays bearing mammal remains deposited in a continental environment (Guerra-Merchán et al. 2012). The deposition of the Pl-3 unit occurred also in the lower Zanclean (pre-FO of the G. puncticulata, Guerra-Merchán et al. 2010) in a restricted area of the eastern sector of the basin reaching nearly to Alhaurín de la Torre. Pleistocene alluvial and travertine deposits directly cover the Zanclean sediments. Although in Fuengirola a small outcrop of open-sea marls of the lower Burdigalian have been noted (Guerra-Merchán et al. 2014), the Torremolinos and Fuengirola sectors share a similar late Neogene sedimentary record. The oldest sediments correspond to the Pl-3 unit, resting directly on the Alpujarride substratum. Unlike the Malaga basin, this unit reaches about 100 m thick and its deposition lasted until the late Zanclean (post-FO of the G. puncticulata, Guerra-Merchán et al.


2000, 2014). In Torremolinos area, a local outcrop, some 5–10 m thick, of coastal sands and gravels overlies the Pl-3 unit. These deposits appear to belong to a new unit (Pl-4 unit) probably early Piacenzian in age, although it cannot be directly dated. As in the Malaga basin, several generations of alluvial fans and travertines also are recognized in the Torremolinos, Mijas and Benalmádena areas (Fig. 2). 3. Main Neogene tectonic features After the main Alpine tectonogenesis, which led to a strong deformation with isoclinal folding, metamorphism, and tectonic stacking in the Betic Internal Zone (Martín-Algarra 1987; Sanz de Galdeano 1997; Serrano et al. 2006; and references therein), the study region is affected

459

by Neogene tectonics characterized mainly by fracturing (Sanz de Galdeano 1983; Sanz de Galdeano and López-Garrido 1991; InsuaArévalo et al. 2012). In Sierra de Mijas, the Neogene faulting can be grouped in four sets, whose approximate directions are: N70-100E; NE-SW; NW-SE, and N-S to NNW-SSE (Andreo and Sanz de Galdeano 1994). The N edge of Sierra de Mijas is marked by a fault N80°E in direction and 60–80°N in dip, which seems to be a continuation of the Albornoque fault (Tubía 1985). Near Alhaurín de la Torre this fault affects the upper Miocene calcarenites (Fig. 2) and towards Alhaurín el Grande cuts the older alluvial deposits. In other sectors, Quaternary alluvial sediments cover the fault, but the mapping of the residual gravity anomalies clearly reveals its continuity (Insua-Arévalo 2008). Striation marks in the fault indicate strike-slip and oblique

Fig. 3. Geological map and topographic profiles (TP-1 to TP-5) showing the Miocene leveling surfaces (LS-1, LS-2 and LS-3/AP-0) in Sierra de Mijas (the letters A and B on the map correspond to sites cited in the text). The UTM coordinates correspond to the central part of each site. In the topographic profiles, the vertical scale is x2. 1: Marbles; 2: Silicate rocks (Alpujarride and Malaguide Complexes); 3: Peridotites; 4: Upper Miocene-Quaternary deposits; AP: Abarcuza peak; CP: Castillejos peak; CaP: Calamorro peak; MP: Mijas peak; PP: Palomas peak; ACF: Acebuchal fault; AF: Arenales fault; BF: Benalmádena fault; APF: Abarcuza-Palomas fault.

460


Fig. 3 (continued).

displacements that seem to have acted mainly during the early and middle Miocene (Sanz de Galdeano and López-Garrido 1991). However, when the fault affects the calcarenites of the upper Miocene or more modern sediments, vertical displacements predominate. This extensional regime can explain the strong subsidence to the N, where more than of 500 m of sediments accumulated in the lower Zanclean (Guerra-Merchán et al. 2014). A sinuous fault varying its orientation between N20-30E and N-S and with a strong dip towards the E (Fig. 2) also marks the eastern edge of Sierra de Mijas. This fault appears to be responsible for the significant subsidence of the area of Torremolinos during the early Pliocene, where about 250 m of silty marls and sands accumulated. Other minor faults limit Sierra de Mijas between Torremolinos and Benalmádena, but they separate areas with minimal subsidence. In addition to the faults described above, Sierra de Mijas is affected by a faulting system NNW-SSE to NNE-SSW oriented and 70–90° in dip. Striations in the fault surfaces show normal and strike-slip displacements. Two major faults of this system (Los Arenales and Benalmádena, Insua-Arévalo 2008) allow us to divide Sierra de Mijas into three geomorphologically distinguishable sectors (Figs. 1B, 2) with a wider central sector. 4. Geomorphological characteristics Several landforms of diverse origin and timing of development characterize the geomorphology of the Costa del Sol between Malaga and Marbella, in which the forming factors (lithology, tectonics, climate, sea-level changes) acted with variable incidence. For a more comprehensive characterization, we analyze the major forms of relief separately: i) mountain relief; ii) abrasion platforms, iii) alluvial fans, and iv) travertine formations.

nearly 5 km wide. Its maximum elevation is c. 1150 m a.s.l. (Mijas peak) in the W sector, declining eastwards to a maximum elevation of around 600 m (Paloma and Abarcuza peaks; Fig. 3A). The hillsides (40–70% of slope), composed of Triassic marbles, have moderately steep relief with low development of a shallow karren karst. Throughout the Sierra de Mijas interfluvial areas occur where the slope decreases significantly to values between 5 and 20%, allowing a greater development of the karren karst. Three staggered old leveling surfaces at different altitudes are identified as LS-1, LS-2, and LS-3 from highest to lowest elevation (Fig. 3 and Table 1). The leveling surfaces are at different elevations in each sector tectonically differentiated above, thus enabling us to evaluate vertical movements between these sectors. Given that no faulting appears in relation to these watersheds with lower gradients and that they cut the Triassic marble succession, a tectonic or lithostratigraphic effect as a forming factor of these old leveling surfaces must be ruled out. In addition, near Mijas peak, heterogeneous marble breccias 3–5 m thick and poorly stratified with a strong reddish-gray cement have been noted above the LS-1 (“A” in Fig. 3). Also, to the NE of Benalmádena (“B” in Fig. 3) another outcrop of marble breccias lies at 380–400 m a.s.l. slightly above the LS-3, which appear to be related (Table 1). At sites on the N edge of the Sierra de Mijas located to the S and SW of Alhaurín de la Torre (Fig. 3, TP-2), LS-3 slopes gently at about 5%. On this surface, no deposits have been detected, due to the soil processes on the karren karst, although it appears to be related to the nearby Tortonian shallow marine deposits (Fig. 2) appearing topographically lower by the effect of the fault on the N edge. Accordingly, LS-3 may represent, at least partially, a Tortonian marine abrasion platform (AP-0) along the N edge. 4.2. Marine abrasion platforms in the pediment

4.1. Main features of the mountain relief Most of the high-mountain landscape in the study area is formed by Sierra de Mijas, an E-W oriented landform of about 20 km long and

In the lowermost part of the N and E borders of Sierra de Mijas, as well as towards the W, in the Sierra Blanca of Coín and Sierra Alpujata to the village of Monda, a slope-break in the marbles can be recognized,

A. Guerra-Merchán et al. / Geomorphology 327 (2019) 456–471 Table 1 Average elevations of the erosive surfaces identified in Sierra de Mijas and estimation of the average uplifting in each sector. ACF: Acebuchal fault; AF: Arenales fault; APF: Abarcuza-Palomas fault; BF: Benalmádena fault.

Average altudes of the erosive surfaces North hillside

Western sector

Central sector

Eastern sector

LS-1

1085

1020

590

545

540

LS-2

940

870

495

430

350

LS-3/AP-0

765

520

425

380

290

AP-1

420

400

320

250

200

South hillside

Western sector

LS-1

Central sector

Eastern sector

1020

690

620

530

LS-2

825

950

555

430

425

LS-3

515

750

465

305

300

AP-1

435

400

270

205

190

Faults in Fig. 3

ACF

AF

BF

Western sector

Central sector

Eastern sector

Upliing from AP-0 (late Tortonian)

755

510

415

370

280

Upliing from AP-1 (early Zanclean)

330

310

230

160

110

Upliing between AP-0 and AP-1

425

200

185

210

170

South hillside

Western sector

Central sector

Eastern sector

Upliing from LS-3 (late Tortonian)

505

740

455

290

290

Upliing from AP-1 (early Zanclean)

345

310

180

115

100

Upliing between AP-0 and AP-1

160

430

275

180

190

Faults in Fig. 3

ACF

AF

BF

up to 700 m-wide appear at 200–260 m a.s.l. carved into Triassic marbles. In the outcrop of the highway service station (A-7 or E-15, 223.5 km), a Quaternary cemented fluvio-deltaic conglomerate bearing marine bivalves overlies this platform (Fig. 4G, H). On the contrary, no abrasion platform was noted in the S hillside of Sierra de Mijas, inside the area defined by the Puerto de los Pescadores, Benalmádena, and Fuengirola, and where metapelites and peridotites predominate (Figs. 2, 4). However, a band of terrain in which the interfluves have shallow slopes (5–20%) can be distinguished (Fig. 4K, L). This band is delimited by two slope-breaks (Fig. 4) around 400 m and 250 m in elevation, respectively, in the western tectonic block, while they appear at 280 m and 120 m a.s. l., respectively, in the eastern tectonic block. It cannot be ruled out that this band might correspond to the remains of the AP-1 abrasion platform in the S hillside. About 40 m below the AP-1 platform, remains of another marine abrasion platform up to 300 m wide (AP-2) appear to the S of Alhaurín de la Torre on the upper Miocene deposits (Fig. 4I), and to the W of Torremolinos sculpted in the Triassic marbles (Fig. 4J). This AP-2 platform lies at a similar altitude to that of the marine deposits of the Zanclean PL-3 unit, thus suggesting a probable correlation. 4.3. Alluvial fans

APF

Average upliing of the Sierra de Mijas from late Tortonian North hillside

461

APF

where the slope decreases to 0–10° (Fig. 4). This flattened relief is highly variable in width, extending N1 km in the Los Nebrales sector (Fig. 4A) to the SW of Alhaurín el Grande, while in other sectors, such as E of Monda (Fig. 4B) and SE of Alhaurín de la Torre (Fig. 4E), it is substantially smaller. The average elevation decreases along the N border of Sierra de Mijas: 420 m a.s.l. to the S of Alhaurín el Grande, 400 m to the ESE of Alhaurín el Grande (Fig. 4C), 320 m in Llanos de Peñaprieta (Alhaurín de la Torre, Fig. 4D), and 200 m in the most E sector (Fig. 4 and Table 1). In general, this platform is interrupted by the fault running along the N edge, giving way to the lower Zanclean yellow silty sands of the PL-2 unit. Locally in Los Nebrales, similar facies several decimeters thick rest on the platform, thus suggesting that this flattened relief corresponds to the lower Zanclean marine abrasion platform (identified as AP-1). On the E edge of Sierra de Mijas between Torremolinos and Benalmádena (Fig. 4F and Table 1) remains of the abrasion platform

Alluvial fans are widely developed in the N and E edges of the Sierra de Mijas and other smaller mountains in the region, as reported by Lhenaff (1981), Insua-Arévalo (2008), and Insua-Arévalo et al. (2012). On the contrary, smaller and isolated alluvial fans appear on the S edge (Figs. 2, 5K). Usually these sedimentary landforms consist of breccias and conglomerates of marble pebbles deposited by debris flow and by sheet or tractive flows showing distal intercalations of sand beds. The lateral coalescence of the fans results in a glacis surface of accumulation changing distally to a wide alluvial plain, currently heavily eroded. Based on the altitudes (Table 2), degree of cementation, facies, and tectonics, the sedimentary record enables the distinction of three major generations of alluvial fans (henceforth AFG-1, AFG-2, and AFG-3; Fig. 2) in the N and E edges of the Sierra de Mijas, which are separated by erosional stages. However, in detail, minor breccia outcrops without a clear relation to any of the three generations appear, thus suggesting a more complex development of the alluvial fans. For each sector, the three generations of alluvial fans developed progressively at lower elevations (Fig. 5A), overlying previously eroded older alluvial fans or Pliocene deposits (Fig. 5G, H, J). The apices of the AFG-1 fans rest above the AP-1 platform (Fig. 4G), while AFG2 and AFG3 have their apices incised in the AP-1 platform or at lower elevations (Fig. 5B). In addition, as with the abrasion platforms, alluvial fans of each generation are arranged at progressively at lower elevations from W to E throughout the Sierra de Mijas (Table 2). The alluvial fans of the AFG-1, reaching 20–30 m thick in the Alhaurín el Grande area (Fig. 2), consist predominantly of heterometric conglomerates deposited by debris flow. The deposits are strongly cemented by a bright-red carbonate containing white marble pebbles, resulting in a characteristic facies called “brecha mortadela” (Lhenaff 1981) with a karstification similar to that of the marbles. To the W of Torremolinos (highway service station) the AFG-1 overlies the AP-1 platform carved on Alpujarride marbles (Fig. 4G). This alluvial fan also shows the typical “brecha mortadela” in the apical zone (about 200 m a.s.l.), while distally (130 m a.s.l.) it contains alternations of rounded conglomerate and calcareous sands bearing oysters and other bivalves (Fig. 5I), thus suggesting the passage from an alluvial fan to a fan delta. Analyses of amino acid racemization/epimerization of oyster specimens showed high D-aIle/L-Ile values (N1.3), thus exceeding the range of the method. By comparison with isoleucine epimerization values of ostreids and Glycymeris shells from Cabo de

462


Huertas site (Torres et al. 2000) and other sites in the Mediterranean realm (Hearty et al. 1986) the AFG-1 of Torremolinos is older than 1.0 Ma and, considering the stratigraphic arrangement, younger than the Zanclean. Alluvial fans of the AFG-2 (up to 10–15 m thick) and AFG-3 (up to 5–10 m thick) show less development than AFG1. Minor cementation with a higher content of the clay fraction and frequent sand intercalations characterize the marble conglomerates of these younger alluvial fans. Regarding the tectonics, it is noteworthy that the AFG-1 alluvial fans are locally tilted 10–30° to N-NNW (Fig. 5C). At most sites these cover the N edge faulting, while in some cases the fans are cut by minor fault surfaces of this system (Fig. 5E), or traces of them can be followed by the development of tectono-karstic cracks with sharply vertical walls following the direction of fracture (Fig. 5F). In fact, the outcrop of AFG-1 of Alhaurín el Grande ends in an almost vertical wall (Fig. 5D) following the normal faulting of the N edge of the sierra (N60-90E and dip 70–80° N). On the contrary, we found no case in which the N edge faulting affects the AFG-2 fans. 4.4. Travertines Staggered at different elevations around Sierra de Mijas and other minor mountains of the region frequent travertine masses of variable sizes and thicknesses occur on the Alpujarride basement or Plio-Pleistocene deposits (Fig. 2). In fact, the villages in the region are usually built on travertine. In the travertines of the study area, no hydrothermal evidence was found, and thus their origin is presumably related to cold water coming from the atmospheric or soil CO2. Therefore, these build-ups correspond to the “Meteogene travertines” of Pentecost and Viles (1994) or the “cool-water travertines” of Ford and Pedley (1992). On the whole, three types of travertine bioconstructions are recognized: i) Spring-type travertines (Magnin et al. 1991). These travertines are located on the S edge of Sierra de Mijas attached to a mountainous carbonate basement close to contact with metapelites, where fountains or springs are frequent (Fig. 6C). The Mijas (TM-1) and Osunilla (TM-2) travertines in the Mijas area, and Benalmádena travertine (TB-1) belong to this group (Fig. 6A, B). ii) Valley-type travertines (Pedley 1990; Pentecost and Viles 1994) filling valleys incised in older travertines or in the basement (Fig. 6C). This type is also recognized in Mijas (TM-2) and in Benalmádena (TB-2) areas (Fig. 6A, B), as well as in Churriana (TCH-3). iii) Travertine-type pool-dam-cascade-slope associations (Pedley 1990; Pentecost and Viles 1994) usually occur far from the marbles and on Pliocene deposits. Travertines belonging to this type are recognized in Torremolinos, Churriana, Alhaurín de la Torre, Alhaurín el Grande, and Coín areas (Fig. 6C). Regarding the chronology of the travertines, Guerra-Merchán et al. (2018) performed analyses based on the methodology of amino acid racemization on gastropods of the family Helicidae from 20 travertine deposits of the study region. The results, in combination with previous datings from Durán et al. (1988), Durán (1996), and Durán et al. (2002) based on the uranium/thorium series and the electric spin resonance methods, allow a visualization of a polyphasic growth of the travertines through the Quaternary concentrated mainly in five episodes, corresponding mostly to odd isotopic stages. Table 3 summarizes information related to the facies, age, and corresponding isotopic episode for each travertine body. Durán et al. (1988) and Durán (1996) suggested a close relationship between the age of the travertines in the S edge and their altitudes, but this is not a general rule. On the contrary, the location appears to be closely related to the presence of springs along the contact between the metapelites and marbles (Fig. 2).

5. Discussion on the chronology of the landforms and analysis of the subsidence-uplift: derivations for a sedimentary-geomorphological evolution Fig. 7 summarizes the events occurring in the region during the Neogene, both in the mountain areas (Sierra de Mijas and other minor sierras) and in the adjacent depressions. As a general result, it can be noted that while the mountain areas specifically underwent erosional processes since the Early Miocene, the basinal areas show alternations of erosional and depositional processes. Below we discuss the chronology of the landforms and the geomorphological and tectono-sedimentary processes occurring in each period.

5.1. Miocene In the study area, the oldest Miocene deposits indicate sedimentation in open marine (Fuengirola) and deep (Malaga basin) environments during the early Burdigalian, suggesting that the Sierra de Mijas had not yet risen. On the contrary, shallow and coastal Tortonian marine deposits crop out in the foothill of the Sierra de Mijas to the S of Alhaurín de la Torre, clearly revealing that this area had already emerged during the Late Miocene. Accordingly, LS-1 and LS-2 leveling surfaces would have formed probably during the middle Miocene, or even LS-1 may have developed in the late Burdigalian (Fig. 7). The local presence of coeval alluvial breccias above the LS-1 corroborates that the region had already emerged during its development. In this framework, LS-1 and LS-2 must correspond mainly to leveling erosional surfaces with local breccia deposits that developed in the pediment of a slightly raised Sierra de Mijas. On the edge N of the Sierra de Mijas, the proximity of the LS-3 to the Tortonian marine deposits suggests that this leveling surface could be, at least partially, its corresponding marine abrasion platform (AP-0). Accordingly, it could be envisioned that, during the Tortonian, the basin of Malaga was part of a narrow and shallow marine passage (Fig. 8A) connecting Atlantic and Mediterranean domains (Serrano 1979; López-Garrido and Sanz de Galdeano 1999; Martín et al. 2001; Schoorl and Veldkamp 2003; Elez et al. 2016), where N300 m of conglomerates and sands were deposited. It is likely that the S boundary of the basin was delimited by the faulting zone of the N edge of Sierra de Mijas, where the marine abrasion platform AP-0 in parallel with LS-3 developed. On the southern side of Sierra de Mijas, locally (NE of Benalmádena) small alluvial fans formed slightly higher than LS-3. Using the average elevations of the AP-0 platform (Table 1) as a reference and considering that the highstand in the late Tortonian was about +10 m in relation to the current sea level (Haq et al. 1987), we can estimate the values of the uplifting for each sector from this age to the present. The results indicate a progressive uplifting towards the W, ranging from 280 to 370 m in the E sector, 415–455 m for the central sector, and up to 505–755 m in the W sector. In addition, the comparison of the differential altitudes of the LS-3 between N and S hillsides suggests that the faults acted with significant scissor-type rotational movements. To the end of the Tortonian, the region could have emerged and been subjected to erosion (Serrano 1979). A similar evolution was described by Schoorl and Veldkamp (2003) for the N sector of the Malaga basin between Pizarra and El Chorro. However, the dramatic sea-level fall in the Mediterranean basin about 5.60 Ma (Clauzon et al. 1996; Krijgsman et al. 1999), which resulted in the Messinian Salinity Crisis (MSC), strongly accentuated the incision of the fluvial network, largely eliminating both the leveling surfaces in the Sierra de Mijas as well as the Tortonian sediments in the Malaga basin. The current Álora and of Pizarra “hachos” making up of Tortonian calcarenites and conglomerates show a significant example of the incision of the fluvial network during the MSC, which cuts the entire Tortonian sequence (250–300 m thick) in such a way that the Zanclean marine sediments


between the two elevations deposited directly on the pre-Tortonian substrate. Before the end of the Messinian, the Mediterranean displayed a transgressive pattern and an increase in the freshwater contribution that culminated with the Lago-Mare dilution event (Rouchy and Caruso 2006). In the study region, this high-water-level framework of the latest Messinian restored the deposition of brackish deposits in the northern part of the Malaga basin (Guerra-Merchán et al. 2010; Serrano and Guerra-Merchán 2014).

5.2. Pliocene The sedimentological and geomorphological evolution through the Pliocene shows major changes driven by sea-level variations as well as by tectonics. The sea-level rise of the latest Messinian during the Lago-Mare event continued at the beginning of the Pliocene with the opening of the Strait of Gibraltar (5.33 Ma, Hilgen and Langereis 1993) and the re-establishing of fully marine conditions in the Mediterranean. The marine waters invaded the river valleys incised during the MSC, reaching a large part of the region up to the Guaro and Monda localities (Fig. 8B). On the other hand, a probable relaxation of the N-S compressive frame could have caused the former strike-slip faults oriented NNW-SSE, NE-SW, and EW to act as normal faults. In this context, a subsidence trench developed between the Sierra de Mijas and the Sierra de Cártama. In this southern sector of the Malaga basin, sediments N 500 m thick of the Pl-2 unit accumulated during the lower Zanclean, representing a subsidence rate of about 1 m/ka (Guerra-Merchán et al. 2014).

463

A close relationship is noticeable between the marine sediments of the PL-2 unit and the broad abrasion platform AP-1 that surrounds the Sierra de Mijas. This suggests that AP-1 platform must have developed during the highstand to the top of the PL-2 unit, dated at 4.6–4.7 Ma (Guerra-Merchán et al. 2012) and coinciding with the eustatic maximum of the third-order cycle TB 3.4 (Haq et al. 1987; Fig. 7). Probably the faults on the N and E edges of the Sierra would limit the extent of the abrasion platform to the N, giving way to marine deposition, while in Los Nebrales sector (SW of Alhaurín el Grande) it could to extend up to the Sierra de los Ángeles (Fig. 8B). On the southern hillside of Sierra de Mijas, the AP-1 platform would have formed on easily eroded rocks (shales, schists, gneisses, and altered peridotites), and thus the poor preservation does not allow its original extent to be estimated. Taking into account the highstands of both ages (+10 m and +90 m, respectively) deduced from the eustatic curve (Haq et al. 1987), we can estimate an uplift of N400 m. In parallel, the comparison between altitudes of the marine abrasion platforms of the late Tortonian AP-0 and the early Zanclean AP-1 platform (Table 1) enables us to estimate the values of the uplifting of Sierra de Mijas within the same time span. The estimations of uplift range between N400 m in the W sector and 170–180 m in the E sector. The Acebuchal fault (ACF), dividing the western sector into two subsectors, shows a notable scissor effect. Thus, in the N hillside the greater uplift (425 m) is reached in the ACF western block, whereas to the E of the ACF the estimated rise is 200 m. The opposite occurs on the S hillside of the W sector, where the greater uplifting (430 m) occurs for the ACF eastern block, while the estimated value for the ACF western block (160 m) is even lower than in the eastern sector of Sierra de Mijas.

Fig. 4. Pliocene abrasion platforms AP-1 and AP-2. The letters on the map correspond to the location of the photographs, which are discussed in the text. AP: Abarcuza peak; CP: Castillejos peak; CaP: Calamorro peak; MP: Mijas peak; ACF: Acebuchal fault; AF: Arenales fault; APF: Abarcuza-Palomas fault; BF: Benalmádena fault; PP: Puerto de los Pescadores; SA: Sierra de los Ángeles.

464


Fig. 4 (continued).

From the early Zanclean (AP-1 platform) to the present-day, Sierra de Mijas also shows a more pronounced uplift towards the W, ranging from 100 to 110 m in the E sector to 330–345 m in the W sector. However, further to the W of the Sierra de Mijas, the greater uplift of as much as 430 m is estimated for the Monda area (Fig. 2). Benalmádena (BF) and Los Arenales (AF) faults, which limit the three sectors differentiated in Sierra de Mijas, indicate the greater activity, with vertical movements between 65 and 130 m. In the case of the AF, a scissor effect is visible, emphasizing the vertical displacement on the southern hillside up to 130 m. On the contrary, the ACF displays only a small vertical displacement (20–35 m) without a significant scissor effect. The tectonic reactivation during the early Zanclean in 4.6–4.7 Ma leads to the interruption and slight deformation of the Pl-2 deposits. On the N edge of Sierra de Mijas, the marine area was limited only to the vicinity of Alhaurín de la Torre (Fig. 8C), where the PL-3 unit deposited during a short time span and the remains of a small abrasion platform AP-2 are preserved. The Torremolinos and Fuengirola areas were of greater subsidence and the marine sedimentation lasted into the late Zanclean. Probably, the marine abrasion platform AP-2 developed during the highstand of the PL-3 unit to the end of the third-order cycle TB 3.4 occurring 4.2–4.3 Ma ago (Guerra-Merchán et al. 2014). In the most eastern sector of Sierra de Mijas (Torremolinos area) the uplifting can be evaluated in the short time span between 4.7 and 4.6 and 4.3–4.2 Ma, since relative tectonic movements seem not to have occurred between the early Zanclean AP-1 and AP-2 marine platforms.

Given that the altitude of the AP-2 is about −40 m with respect to AP-1, whereas the eustatic fall (Haq et al. 1987) shows only differences of about −20 m, an uplifting of around 20 m can be inferred. At the end of the Zanclean (3.8 Ma) a eustatic fall of more of than 100 m occurred, marking the end of the cycle TB 3.5 (Haq et al. 1987) and leaving the region emerged and subject to erosion. The subsequent transgression during the early Piacenzian beginning the TB3.6 cycle affects only the E part of the region, where coastal and shallow marine deposits comprising the Pl-4 unit are preserved in the Torremolinos area. However, this unit is better represented to the W, in the areas of Estepona and San Roque (Guerra-Merchán et al. 2014) outside the study area. 5.3. Pleistocene In the Western Costa del Sol, late Piacenzian-Gelasian deposits have not been recognized. This period is characterized by a trend of a falling sea level due to climate cooling (Miller et al. 2005), suggesting that the region had emerged and was subject to erosion. Presumably, an erosional glacis surface (pediment) developed around the Sierra de Mijas, which is poorly preserved at present below the oldest alluvial Pleistocene deposits. A similar surface was described by GuerraMerchán et al. (2004) in the eastern Costa del Sol (Nerja sector) related to the cold period occurring during the late Gelasian and early Calabrian. The end of this period was dated to 1.46 Ma BP in the ODP-sites 975 and


465

Fig. 5. General features on Pleistocene alluvial fans. A. Photograph illustrating the development of three generations of alluvial fans at different heights and progressively farther from the relief of the Sierra de Mijas. B. Development of the apices of AFG-2 at a height lower than that of AP-1 platform. C. Layers of conglomerates of the tilted AFG-1. D. Outcrop of AFG-1 to the S of Alhaurín el Grande ending in an almost vertical wall, which corresponds to the normal fault of the edge N of the Sierra de Mijas. E. Fault plane in conglomerates of AFG-1. F. Tectono-karstic cracks with sharply vertical walls following the direction of fracture. G and H. Geological sections showing the relationship between AFG-1, AFG-2 and Pliocene marine deposits (PI-2 unit); I. Oysters in rounded conglomerate and calcareous sands of the AFG-1. J. Discontinuity between Pliocene marine deposits (Pl-3 unit) and the AFG-1. K. Outcrop of AFG-1 covering the hillside of the S edge of the Sierra de Mijas.

976 from the Western Mediterranean and Alboran Sea (Serrano et al. 1999; González-Donoso et al. 2000). Several generations of alluvial deposits and travertine build-ups make up the Pleistocene sedimentation, these being staggered in the Sierra de Mijas and other nearby mountains. The alluvial fans reach great development on the N and E edges of Sierra de Mijas, resulting in a piedmont plain formed by lateral coalescence and extending distally in alluvial plains (Fig. 8D). In the area of Torremolinos, the

proximity of these fans to the shoreline allowed the development of a fan delta. On the contrary, the scant subsidence on the S edge resulted in relatively thin alluvial deposits that are currently poorly preserved. No chronometric ages or accurate biostratigraphic data are available for the alluvial fans. From former studies, Estévez González and Chamón (1978) assigned a Plio-Pleistocene age for the whole of the alluvial deposits, without differentiating depositional stages. Lhenaff (1981) annotated a Villafranchian age for the older fans and ages between the

466


Table 2 Range of altitudes (m a.s.l.) for the three generations of alluvial fans. Alluvial-fan generations

AFG-1 AFG-2 AFG-3

North edge Western sector

Central sector

Eastern sector

460–300 300–170 170–160

? 200–100 100–60

? 100–60 70–30

East edge

200–140 130–80 120–40

Riss and the Würm for the most recent fans. Rodríguez-Vidal et al. (2007) considered a Middle Pliocene age for the fan delta of Tajo Colorado (Torremolinos sector) based on an assumed conformity with the underlying lower Pliocene deposits. Insua-Arévalo (2008)

and Insua-Arévalo et al. (2012) assigned the AFG-1 to the Late Pliocene or an older age, the AFG-2 to the Middle-Late Pleistocene, and the AFG-3 to the Late Pleistocene or even Holocene. As indicated in the Results section, three main generations of alluvial fans can be distinguished based on the facies, degree of cementation, and geomorphological context. Similar patterns have also been identified in other sectors of S and SE Spain: Nerja (Guerra-Merchán et al. 2004), Campo de Dalías (Rodríguez-Fernández and Martín-Penela 1993), Almeria-Cabo de Gata (Harvey et al. 1999), and Lorca-MurciaAlicante (Silva et al. 1992; Goy et al. 1993). The imprecise chronological control of the alluvial fans prevents the assignation of each AFG to specific climatic stages. However, as a general rule, in addition to an abrupt change in the slope gradient, alluvial fans that formed predominantly by debris flow require an abundant availability of detrital supply from

Fig. 6. Geological map and representative sections showing the travertine development in two phases in Mijas (A) and Benalmádena (B) sectors. C. Sedimentary models for the travertines of Sierra de Mijas.


467

Table 3 Characterization of the travertines developed in Sierra de Mijas. Episodes, facies, types, and chronology for each travertine. Locality

Episodes

Datings (ky)

TM-2

22.6 (±11.0)* 24.5 (±2.4)* 28.9 (±10.2)* 40.3 (±13.1)* 52,6 (±12.4)*

TM-1 TB-2

Mijas

MIS

Type of travertine

Facies

3

Valley and locally spring

Bioconstructed facies with abundant rest of higher plants Fine-grained carbonate facies with oncolitic gravels, intercalated in detrital facies Locally cascade-slope facies

217 (± 15–20%)**

7

Spring

43.1 (±16.2)*

3

Valley

5

Spring

Benalmádena

TT-3 TT-2 TT-1

86.3 (± 15–20%)** 109 (± 15–20%)** 25.3 (±15–20%)** 26.5 (±15–20%)** 27.3 (±1.7)** 64.6 (±25,3)* 113.7 (±52.7)* 147 (+9.2/−8.5)****

TCH-4

6.4 (±6.4)*

TB-1 TT-4 Torremolinos

Churriana

TCH-3 TCH-2 TCH-1 TAT-3 TAT-2

28.8 (±8.5)* 42.8 (±18.0)* 88.0 (±28.2)* 75.4 (+14.8/−13.0)*** N350*** 42.3 (±14.0)* 7.2 (±3.9)*

3 4 5 6

Pool-dam- cascade

1

Pool-dam- cascade

3

Valley

5 ¿? 3 1

Pool-dam- cascade Filling of cavities

Alhaurín de la Torre

Alhaurín el Grande

Coín

TAT-1

242.9 (+17.6/−61.0)***

7

Pool-dam- cascade

TAG-1

28.7 (+3.0/−2.8)***

3

Pool-dam- cascade

TC-2 TC-1

11.6 (±6.3)* 13.4 (±14.4)* 20.3 (±5.5)* 36.9 (±16.7)* –

2–1 3–2

Pool-dam- cascade

Bioconstructed facies with abundant rest of higher plants and cascade-slope facies Bioconstructed facies with abundant rest of higher plants, cascade-slope facies and fine-grained carbonate facies with oncolitic gravels Bioconstructed facies with abundant rest of higher plants and cascade-slope facies Fine-grained carbonate facies with oncolitic gravels, bioconstructed facies with abundant rest of higher plants and cascade-slope facies Fine-grained carbonate facies with oncolitic gravels and bioconstructed facies with abundant rest of higher plants Fine-grained carbonate facies with oncolitic gravels, intercalated with detrital facies Fine-grained carbonate facies with oncolitic gravels, bioconstructed facies with abundant rest of higher plants and cascade-slope facies Earthy material with remains of travertine Fine-grained carbonate facies with oncolitic gravels, bioconstructed facies with abundant rest of higher plants and cascade-slope facies Fine-grained carbonate facies with oncolitic gravels, bioconstructed facies with abundant rest of higher plants and cascade-slope facies Fine-grained carbonate facies with oncolitic gravels, bioconstructed facies with abundant rest of higher plants and cascade-slope facies

?

Datings by: * Guerra-Merchán et al. (2018); ** Durán et al. (1988); *** Durán (1996); **** Durán et al. (2002).

mountainous areas, and a poor vegetation cover favors the erosion and detrital transport. These assumptions suggest that dry periods (warm or temperate) are the most favorable for the development of alluvial fans in the foothills of mountainous relief. Nevertheless, frequent and highly significant climatic changes with glacial/interglacial variations during the last 2.4 Ma, resulted in recurring favorable conditions for the alluvial-fan development. To examine the chronology of these Quaternary landforms (Fig. 7), we used as a correlation reference the climate events based on stable isotope (von Grafenstein et al. 1999) and on changes in the planktonic foraminifera assemblages (GonzálezDonoso et al. 2000) noted in the ODP-site 976, which was performed in the Alboran sea, offshore Malaga. On analyzing the racemization of amino acids in oysters found in the delta part of the AFG-1, we deduce that these alluvial fans are older than 1.0 Ma and younger than the underlying Pliocene deposits (early Piacenzian, in the Torremolinos area). Otherwise, the AFG-1 fans are below the travertine buildups, so that they pre-date the beginning of the travertine development in the area (before 350 ka, TCH-1 in Table 3). Thus, we conclude that the AFG-1 alluvial fans could be formed during late Gelasian-early Calabrian. In this case, AFG-1 would be correlated with the first generation of alluvial fans in the Nerja area (Guerra-Merchán et al. 2004). The authors assigned this fan generation to a relatively warm period occurring between 1.46 and 1.19 Ma, which was detected by González-Donoso et al. (2000) from the ODP-site 976 (Alboran Sea). If this correlation is correct, the age of the AFG-1 would be restricted to the early Calabrian (Fig. 7). Two events can be detected between the formation of AFG-1 and that of AFG-2. On the one hand tectonic activity, which is revealed because some AFG-1 are tilted and affected by normal faults, whereas

these features are not noted in the AFG-2. On the other hand, erosional surfaces on the boundary between AFG-1 and AFG-2 indicate an incision of the fluvial network, which may be related to the sea-level fall that occurred during the ‘Mid-Pleistocene Revolution’ (MPR) dated at 0.90–0.92 Ma. Hernández Molina et al. (2002) detected the MPR discontinuity on the continental shelves of the southern Iberian Peninsula and, based on changes in the planktonic foraminifera assemblages, González-Donoso et al. (2000) distinguished a predominantly cold interval Q-3 ranging between 0.62 and 1.19 Ma in the ODP-site 976. The second generation of alluvial fans (AFG-2) developed mainly along the N and E edges of Sierra de Mijas on a pediment surface (Figs. 5G, H, 8E), while on the S edge, alluvial deposits filled incised valleys, but no significant alluvial fans formed. In parallel with the formation of the alluvial fans, travertine buildups developed on the mountain slopes. The major stages of travertine growth occurred mostly in warm and moist episodes of the odd isotopic stages (Table 3). This is consistent with the results reported from other areas the Mediterranean and Northern Europe (Henning et al. 1983; Martínez-Tudela et al. 1986; Durán 1996; Kronfeld et al. 1988; Frank et al. 2000; Peña et al. 2000; Martín-Algarra et al. 2003; and references therein). Accordingly, the development of alluvial fans and travertines could alternate in time throughout the Quaternary. The oldest travertine is the TCH-1 in Churriana, estimated by Durán (1996) to be older than 350,000 years. Datings from the secondgeneration travertines (Durán et al. 1988; Durán 1996) locate this episode in the upper part of the Middle Pleistocene, roughly coinciding with isotope stage 7. In Mijas (TM-1) and Alhaurín de la Torre, the travertines of the second generation contain detrital beds changing transitionally to alluvial deposits AFG-2, thus implying a partial

468


Fig. 7. Chronology of main events recognized in the studied area in relation to the eustatic curve and sedimentary cycles from Haq et al. (1987), and the climate proxies from the Quaternary ODP-976 sediments: SST curve from González-Donoso et al., (2000) and isotopic stages from von Grafenstein et al. (1999).

simultaneity of the two landforms. Given that no signs of tectonic activity are noted in the AFG-2 or in the above-mentioned travertines, the erosion of these landforms prior to overlying deposits should be attributed to an incision of the fluvial network due to a low base-level following eustatic sea-level fall. Hernández Molina et al. (1994) detected a regressive, low sea-level interval on the continental platform of the Alboran Sea between Malaga and Gibraltar, beginning approximately in 80 ka BP. This regression can be correlated with a cold period detected in the ODP-site 976 dated between 95 and 70 ka BP (GonzálezDonoso et al. 2000). The third travertine stage gave rise to the travertine build-ups TB-1 of Benalmádena, TT-2 of Torremolinos, and TCH-2 of Churriana. Since datings by Durán et al. (1988 and 2002), Durán (1996), and GuerraMerchán et al. (2018), the age of these travertines ranges between 147.0 + 9.2/−8.5 ka from TT2 and 75.4 ± 15 ka from TCH-2, during the lower part of the Late Pleistocene. Alluvial fans that formed in this interval are not detected, but they could have been eroded or covered by the progadation of fans belonging to the AFG-3. The fourth growth phase of the travertine led to the greater and more numerous build-ups, located in Mijas (TM-2), Benalmádena (TB-2), Torremolinos (TT-3 and TT-4), Churriana (TCH3), Alhaurín el Grande, and Coín (TC-2 lower part). These travertines provide ages in the latest Pleistocene, ranging between 52.6 ± 12.4 ka and 22.6 ± 11 ka, and therefore these travertines built up during isotopic stage 3. The stratigraphic relations between these travertines with the alluvial deposits of the AFG-3 suggest that they are of the similar age. As with

AFG-2, alluvial fans developed mainly along the N and E edges of Sierra de Mijas, whereas alluvial deposits on the S edge are rare (Fig. 8F). Later, the sea-level fall caused by the last glacial period (minimum eustatic sea level between 20 and 18 ka BP; CLIMAP 1976, 1984) appear to have led to a new erosional phase and the incision of the fluvial network. The last travertine episode would result in the Coín (TC-2 upper part) and Churriana (TCH-4) build-ups, which provide ages between 13.4 and 6.4 ka. Although these data are imprecise due to their ample margins of error, they may be placed within the framework of the last deglaciation. At the same time, fluvial deposits appear to have accumulated, constituting recent terraces and, finally, the present-day flood plains and channels. 6. Conclusions The landscape of the territory of the western Costa del Sol between Malaga and Marbella shows a Late Miocene to present-day evolution driven by tectonics, climate, and sea-level changes. In the high-mountain relief composed mainly of Alpujarride marbles, three erosive leveling surfaces (LS-1, LS-2 and LS-3) developed in the Miocene, which appear staggered from top to bottom according to their age. LS-1 and LS-2 are continental in origin and were generated during late Burdigalian-Middle Miocene. They correspond mainly to erosive pediment surfaces developed in a slightly raised Sierra de Mijas. LS-3 corresponds in part to a marine abrasion platform (AP-0)


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Fig. 8. Paleogeographic and geomorphological evolution of the study region since late Neogene. A: late Tortonian; B: early Zanclean (Pl-2 unit); C: upper part of the early Zanclean (Pl-3 unit); D: early Pleistocene; E: middle Pleistocene; F: late Pleistocene. 1: Marine area (P: abrasion platform); 2: Emerged area (AF: Alluvial fan; AP: Alluvial plain; PF: alluvial fans of the previous generations; TR: Travertines; CM: Current mountain relief of Sierra de Mijas. PP: Puerto de los Pescadores; SA: Sierra de los Ángeles.

formed in the Late Miocene, probably during the highstand of the late Tortonian. In parallel, significant detrital deposits accumulated in the Malaga basin. At present, each leveling surface appears at different elevations due to NE-SW and NNW-SSE faults, which divide the Sierra de Mijas into three main blocks, progressively uplifted from E to W. The incision of the fluvial network caused by the Messinian Salinity Crisis leaves a marked imprint on the region, eliminating most of the Tortonian sedimentation and the leveling surfaces mentioned above. The subsequent marine transgression at the beginning of Pliocene led to the main stage of filling in the Malaga basin (PL-2 unit) during the early Zanclean, and the development of the marine abrasion platform AP-1 widely recognized around the Sierra de Mijas and other minor sierras. The tectonic pulse at 4.6–4.7 Ma uplifted the region, thus emerging most of the Malaga basin. On the contrary, the Torremolinos and Fuengirola basins continued as subsidence areas under marine regime during the first part of the late Zanclean. As a consequence, the deposition of the PL-3 unit and a most limited abrasion platform AP-2 developed below AP-1. The different elevations both of the tops of the sedimentary sequences in the Malaga basin and of the marine abrasion platforms (AP-0, AP-1 and AP-2) in the Sierra de Mijas allow an evaluation of the regional tectonic uplifting since the Late Miocene, as well as an estimation of the rotational scissor-type movements of the main faults. In a low sea-level framework and progressive uplifting of the region, erosional processes took place mainly during the Late Pliocene and

Gelasian. The incision of the fluvial network and a pediment surface around the Sierra de Mijas are the most noteworthy landforms that developed during this time span. Climate-eustatic changes exerted a predominant influence on the configuration of the landscape during the Quaternary. Alluvial fans of three different generations interrupted by stages of erosion and incision of the fluvial network characterize the landforms formed probably during dry (warm or temperate) periods. In addition, travertine growths in five distinct phases occur, usually coinciding with the humid and warm, odd-numbered isotopic stages. The terrains of the Western Costa del Sol, located in the westernmost Mediterranean and belonging to the Alboran domain, represent an outstanding example of the influence of major tectonic and climatic factors in the development of the landscape. On the one hand, the Neogene tectonics induced by the relative movements between the African and Eurasian plates on a small continental lithosphere fragment (Alboran block). On the other hand, the effects of major paleogeographic changes caused by the Messinian Salinity Crisis and the subsequent marine re-flooding of the Mediterranean after the opening of the nearby Strait of Gibraltar at the beginning of the Pliocene. Acknowledgements This study was supported with funding provided by Research Group RNM-146 of the “Junta de Andalucía” and project CGL2016-78577-P of

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the Spanish Ministry of Science and Innovation. We thank the interesting criticisms and remarks of the editor Dr. Andrew James Plater, as well as those of two anonymous reviewers whose insightful remarks and suggestions have substantially improved the manuscript. We also wish to thank Mr. David Nesbitt for the English revision of the manuscript. References Andreo, B., Sanz de Galdeano, C., 1994. Structure of the Sierra de Mijas (Alpujarride complex, Betic Cordillera). Ann. Tectonicae 8, 23–35. Andrieux, J., Fontboté, J.M., Mattauer, M., 1971. Sur un modèle explicatif de l'Arc de Gibraltar. Earth Planet. Sci. Lett. 12, 191–198. Boccaletti, M., Gelati, R., López-Garrido, A.C., Papani, G., Rodríguez-Fernández, J., Sanz de Galdeano, C., 1987. Neogene-Quaternary sedimentary-tectonic evolution of the Betic Cordillera. Acta Natur. Aten.-Parm. 23, 179–200. Braga, J.C., Martín, J.M., Quesada, C., 2003. Patterns and average rates of late Neogenerecent uplift of the Betic Cordillera, SE Spain. Geomorphology 50, 3–26. Calvache, M.L., Viseras, C., 1997. Long-Term control mechanisms of stream piracy processes in Southeast Spain. Earth Surf. Process. Landf. 22, 93–105. Cita, M.B., 1975. Studi sul Pliocene e sugli strati di passaggio dal Miocene al Pliocene. VIII Planktonic foraminiferal biozonation of the Mediterranean Pliocene deep sea record. A revision. Riv. Ital. Paleontol. Stratigr. 81, 527–544. Clauzon, G., Suc, J.P., Gautier, F., Berger, A., Loutre, M.F., 1996. Alternate interpretation of the Messinian salinity crisis: controversy resolve? Geology 24, 363–366. CLIMAP, 1976. The surface of the iceage earth. Science 191, 1131–1137. CLIMAP, 1984. The last interglacial ocean. Quat. Res. 21, 123–224. Durán, J.J., 1996. Los sistemas Kársticos de la provincia de Málaga y su evolución: contribución al conocimiento paleoclimático del Cuaternario en el Mediterráneo Occidental. PhD Thesis. Univ. Complutense Madrid, Spain. Durán, J.J., Grün, R., Soria, J., 1988. Edad de las formaciones travertinas del flanco meridional de la Sierra de Mijas (provincia de Málaga, Cordilleras Béticas). Geogaceta 5, 61–63. Durán, J.J., Carrasco, F., Andreo, B., Marqués, I., Baldomero, A., Ferrer, I.E., Cortés, M., 2002. Aspectos cronoestratigráficos de los travertinos de Torremolinos (Málaga, Sur de España), a partir de nuevos datos del yacimiento arqueológico del Bajondillo. In: Carrasco, F., Durán, J.J., Andreo, B. (Eds.), Karst and Environment. Fundación Cueva de Nerja. Málaga, Spain, pp. 465–470. Durand-Delga, M., Fontboté, J.M., 1980. Le cadre structural de la Méditerranée occidentale. 26 Congrès. Les Chaînes alpines issues de la Téthys. Mém. B.R.G.M. 115. Géol. Intern, Paris, pp. 67–85. Elez, J., Silva, P.G., Huerta, P., Perucha, M.A., Civis, J., Roquero, E., Rodríguez-Pascua, M.A., Bardají, T., Giner-Robles, J.L., Martínez-Graña, A., 2016. Quantitative paleotopography and paleogeography around the Gibraltar Arc (South Spain) during the Messinian Salinity Crisis. Geomorphology 275, 26–45. Estévez González, C., Chamón, C., 1978. Memoria y Mapa Geológico de España a escala 1: 50.000, Hoja de Málaga-Torremolinos (1.053). IGME, Madrid. Ford, T.D., Pedley, H.M., 1992. Tufa deposits of the world. J. Speleol. Soc. Jpn. 17, 46–63. Frank, N., Braum, F.N., Hambach, M., Mangini, A., Wagner, G., 2000. Warm period growth of travertine during the Last Interglaciation in Southern Germany. Quat. Res. 54 (1), 38–48. Galindo-Zaldívar, J., Jabaloy, A., Serrano, I., Morales, J., González-Lodeiro, F., Torcal, F., 1999. Recent and present-day stresses in the Granada Basin (Betic Cordilleras): example of a late Miocene-present-day extensional Basin in a convergent plate boundary. Tectonics 18, 686–702. González-Donoso, J.M., Serrano, F., Linares, D., 2000. Sea surface temperature during the Quaternary at ODP sites 976 and 975 (western Mediterranean). Palaeogeogr. Palaeoclimatol. Palaeoecol. 162, 17–44. Goy, J.L., Zazo, C., Bardají, T., Somoza, L., Causse, C., Hillaire-Marcel, C., 1993. Eléments d'une chronostratigraphie du Tyrrhénien des régions d'Alicante-Murcia, Sud-Est de l'Espagne. Geodin. Acta 6 (2), 103–119. von Grafenstein, M.R., Zahn, R., Tiedemann, R., Murat, A., 1999. Planktonic δ18 Records at sites 976 and 977, Alboran Sea: stratigraphy, forcing and paleoceanographic implications. In: Zahn, R., Comas, M.C., Klaus, A. (Eds.), Proceedings of the Ocean Drilling Program Scientific Results. vol. 161. Texas A & M University, Austin, TX, pp. 469–479. Guerra-Merchán, A., Serrano, F., Ramallo, D., 2000. El Plioceno de la Cuenca de Málaga (Cordillera Bética). Geotemas 2, 107–110. Guerra-Merchán, A., Serrano, F., Ramallo, D., 2004. Geomorphic and sedimentary Plio-Pleistocene evolution of the Nerja area (northern Alboran basin, Spain). Geomorphology 60, 89–105. Guerra-Merchán, A., Serrano, F., Garcés, M., Gofas, S., Esu, D., Gliozzi, E., Grossi, F., 2010. Messinian Lago-Mare deposits near the Strait of Gibraltar (Malaga Basin, S Spain). Palaeogeogr. Palaeoclimatol. Palaeoecol. 285, 264–276. Guerra-Merchán, A., Serrano, F., Ruiz Bustos, A., Garcés, M., Insua-Arévalo, J.M., GarcíaAguilar, J.M., 2012. Approach to the Lower Pliocene marine-continental correlation from southern Spain. The micrommamal site of Alhaurín el Grande-1 (Málaga Basin, Betic Cordillera, Spain). Estud. Geol. 69 (1), 85–96. Guerra-Merchán, A., Serrano, F., Hlila, R., El Kadiri, Kh., Sanz de Galdeano, C., Garcés, M., 2014. Tectono-sedimentary evolution of the peripheral basins of the Alboran Sea in the arc of Gibraltar during the latest Messinian-Pliocene. J. Geodyn. 77, 158–170. Guerra-Merchán, A., Serrano, F., García-Aguilar, J.M., Ortiz, J.E., Torres, T., SánchezPalencia, Y., 2018. Development of Quaternary travertines in the carbonate mountains of the Western Costa del Sol (Malaga, S Spain). Quat. Res. (in press). Haq, B.U., Hardenbol, J., Vail, P.R., 1987. Chronology of fluctuating sea levels since the Triassic (250 million years ago to present). Science 235, 1156–1167.

Harvey, A.M., 1984. Aggradation and dissection sequences on Spanish alluvial fans: influence on morphological development. Catena 11, 289–304. Harvey, A.M., 1987. Alluvial fan dissection: Relationship between morphology and sedimentation. In: Frostik, L., Reid, I. (Eds.), Desert Sediments: Ancient and Modern. vol. 35. Geol. Soc. London Spec. Publ., pp. 87–103. Harvey, A.M., 2002. The role of base-level changes in the dissection of alluvial fans: case studies from southeast Spain and Nevada. Geomorphology 45, 67–87. Harvey, A.M., Silva, P.G., Mather, A.E., Goy, J.L., Stokes, M., Zazo, C., 1999. The impact of quaternary sea-level and climatic change on coastal alluvial fans in the Cabo de Gata ranges, southeast Spain. Geomorphology 28, 1–22. Hearty, P.J., Miller, G.H., Stearns, C.E., Szabo, B.J., 1986. Aminostratigraphy of Quaternary shorelines in the Mediterranean basin. Geol. Soc. Am. Bull. 97, 850–858. Henning, G.J., Grünn, R., Brunacker, K., 1983. Speleothems, travertines and paleoclimates. Quat. Res. 20, 1–29. Hernández Molina, F.J., Somoza, L., Rey, J., Pomar, L., 1994. Late Pleistocene-Holocene sediments on the Spanish continental shelves: model for very high resolution sequence stratigraphy. Mar. Geol. 120, 129–174. Hernández Molina, F.J., Somoza, L., Vázquez, J.T., Lobo, F., Fernández-Puga, M.C., Llave, E., Díaz-del Río, V., 2002. Quaternary stratigraphic stacking patterns on the continental shelves of the southern Iberian Peninsula: their relationship with global climate and palaeoceanographic changes. Quat. Int. 92, 5–23. Hilgen, F.J., Langereis, C.G., 1993. A critical re-evaluation of the Miocene/Pliocene boundary as defined in the Mediterranean. Earth Planet. Sci. Lett. 118, 167–179. Insua-Arévalo, J.M., 2008. Neotectónica y Tectónica Activa de la Cuenca de Málaga (Cordillera Bética Occidental). PhD Thesis. Univ. Complutense Madrid, Spain. Insua-Arévalo, J.M., Martínez-Díaz, J.J., García-Mayordomo, J., Martín-González, F., 2012. Active tectonics in the Malaga Basin: evidences from morphotectonic markers (Western Betic Cordillera, Spain). J. Iber. Geol. 38 (1), 175–190. Krijgsman, W., Hilgen, F.J., Raffi, I., Sierro, F.J., Wilson, D.S., 1999. Chronology, causes and progression of the Messinian salinity crisis. Nature 400, 652–655. Kronfeld, J., Vogel, J.C., Rosenthal, E., Weinstein-Evron, M., 1988. Age and paleoclimatic implications of Bet Shean travertines. Quat. Res. 30, 298–303. Lhenaff, R., 1981. Recherches géomorphológiques sur les Cordillères Bétiques Centro-Occidentales (Espagne). PhD Thesis. Univ. Lille, France. Lonergan, L., White, N., 1997. Origin of the Betic-Rif mountain Belt. Tectonics 16 (3), 504–522. López-Garrido, A.C., Sanz de Galdeano, C., 1999. Neogene sedimentation and tectoniceustatic control of the Málaga Basin, South Spain. J. Pet. Geol. 22, 81–96. Magnin, F., Guendon, J.L., Vaudour, J., Martinf, Ph., 1991. Les travertins: accumulations carbonatées associées aux systémes karstiques, séquences sédimentaires et paléo-environnements quaternaires. Bull. Soc. Geol. Fr. 162 (3), 585–594. Martín, J.M., Braga, J.C., Betzler, C., 2001. The Messinian Guadalhorce corridor: the last northern, Atlantic-Mediterranean gateway. Terra Nova 13, 418–424. Martín-Algarra, A., 1987. Evolución geológica alpina del contacto entre las Zonas Internas y las Zonas Externas de la Cordillera Bética. PhD Thesis. Univ. Granada, Spain. Martín-Algarra, A., Martín-Martín, M., Andreo, B., Juliá, R., González-Gómez, C., 2003. Sedimentary patterns in perched spring travertines near Granada (Spain) as indicators of the paleohydrological and paleoclimatological evolution of a karst massif. Sediment. Geol. 161, 217–228. Martínez-Tudela, A., Cuenca, F., Santisteban, C., Grun, R., Hentzsch, B., 1986. Los travertinos del Río Matarraña, Beceite (Teruel) como indicadores paleoclimáticos del Cuaternario. In: López-Vera, A. (Ed.), Quaternary Climate in Western Mediterranean. Univ. Autónoma Madrid, pp. 307–324. Mather, A.E., 2000. Adjustment of a drainage network to capture induced baselevel change: an example from the Sorbas Basin, SE Spain. Geomorphology 34, 271–289. Miller, K.G., Kominz, M.A., Browning, J.V., Wright, J.D., Mountain, G.S., Katz, M.E., Sugarman, P.J., Cramer, B.S., Christie-Blick, N., Pekar, S.F., 2005. The Phanerozoic Record of Global Sea-level Change. Science 310, 1293–1298. Montenat, C.,. (Coord.), 1990. Les bassins neogenes du domaine Betique oriental (Espagne). Doc. et. Trav. 12–13. IGAL, Paris (392 pp). Pedley, H.M., 1990. Classification and environmental models of cool freshwater tufas. Sediment. Geol. 68, 143–154. Peña, J.L., Sancho, C., Lozano, M.V., 2000. Climatic and tectonic significance of Late Pleistocene and Holocene tufa deposits in the Mijares river canyon, eastern Iberian range, Northeast Spain. Earth Surf. Process. Landf. 25, 1403–1417. Pentecost, A., Viles, H.A., 1994. A review and reassessment of travertine classification. Géog. Phys. Quatern. 48, 305–314. Rodríguez-Fernández, J., Martín-Penela, A.J., 1993. Neogene evolution of the Campo de Dalias and the surrounding offshore areas - (Northeastern Alboran Sea). Geodin. Acta 6, 255–270. Rodríguez-Fernández, J., Sanz de Galdeano, C., 2006. Late orogenic intramontane basin development: the Granada basin, Betics (southern Spain). Basin Res. 18, 85–102. Rodríguez-Vidal, J., Abad, M., Cáceres, L.M., González-Regalado, M.L., Lozano-Francisco, M.C., Ruiz, F., Vera-Peláez, J.L., Cortés Sánchez, M., de la Rubia de Gracia, J.J., Simón Vallejo, M.D., 2007. Rasgos morfosedimentarios del piedemonte nororiental de la sierra de Mijas (Torremolinos, Málaga). Torremolinos. In: Cortés Ramos, M. (Coord.), Bajondillo, Cueva (Eds.), Secuencia cronocultural y paleoambiental del Cuaternario reciente en la Bahía de Málaga. Servicio de Publicaciones del Centro de Ediciones de la Diputación de Málaga, Málaga, Spain, pp. 25–35. Rouchy, J.M., Caruso, A., 2006. The Messinian salinity crisis in the Mediterranean basin: a reassessment of the data and an integrated scenario. Sediment. Geol. 188–189, 35–67. Sanz de Galdeano, C., 1983. Los accidentes y fracturas principales de las Cordilleras Béticas. Estud. Geol. 39, 157–165.

A. Guerra-Merchán et al. / Geomorphology 327 (2019) 456–471 Sanz de Galdeano, C., 1990. Geologic evolution of the Betic Cordilleras in the Western Mediterranean, Miocene to the present. Tectonophysics 172, 107–119. Sanz de Galdeano, C., 1997. La Zona Interna Bético-Rifeña (Antecedentes, unidades tectónicas, correlaciones y bosquejo de reconstrucción paleogeográfica). Monográfica Tierras del Sur. Univ. Granada, Spain. Sanz de Galdeano, C., Alfaro, P., 2004. Tectonic significance of the present relief of the Betic Cordillera. Geomorphology 63, 175–190. Sanz de Galdeano, C., López-Garrido, A.C., 1991. Tectonic evolution of the Málaga Basin (Betic Cordillera). Regional implications. Geodin. Acta 5, 173–186. Sanz de Galdeano, C., Vera, J.A., 1992. Stratigraphic record and palaeogeographical context of the Neogene basins in the Betic Cordillera, Spain. Basin Res. 4, 21–36. Sanz de Galdeano, C., Serrano, F., López-Garrido, A.C., Martín Pérez, J.A., 1993. Palaeogeography of the Late Aquitanian-Early Burdigalian basin in the western Betic internal zone. Geobios 26, 43–55. Schoorl, J.M., Veldkamp, A., 2003. Late Cenozoic landscape development and its tectonic implications for the Guadalhorce valley near Álora (Southern Spain). Geomorphology 50, 43–57. Serrano, F., 1979. Los foraminíferos Planctónicos del Mioceno superior de la cuenca de Ronda y su comparación con los de otras áreas de las Cordilleras Béticas. PhD Thesis. Univ. Málaga, Spain. Serrano, F., Guerra-Merchán, A., 2004. Geología de la provincia de Málaga. Servicio de Publicaciones. Centro de Ediciones de la Diputación Provincial de Málaga, Málaga, Spain. Serrano, F., Guerra-Merchán, A., 2014. Comment on the paper “Lago Mare and the Messinian salinity crisis: Evidence from the Alboran Sea (S. Spain)” by Do Couto et al. (2014). Mar. Pet. Geol. 65, 334–339.

471

Serrano, F., Sanz de Galdeano, C., Delgado, F., López-Garrido, A.C., Martín-Algarra, A., 1995. The Mesozoic and Cenozoic of the Malaguide complex in the Málaga area: a Paleogene olistostrome-type chaotic complex (Betic Cordillera, Spain). Geol. Mijnb. 74, 105–116. Serrano, F., González-Donoso, J.M., Linares, D., 1999. Biostratigraphy and paleoceanography of the Pliocene at Sites 975 (Menorca rise) and 976 (Alboran sea) from a quantitative analysis of the Planktonic foraminiferal assemblages. In: Zahn, R., Comas, M.C., Klaus, A. (Eds.), Proceedings of the Ocean Drilling Program, Scientific Results 161, College Station TX, pp. 185–195. Serrano, F., Guerra-Merchán, A., El Kadiri, Kh., Sanz de Galdeano, C., López-Garrido, A.C., Martín-Martín, M., Hlila, R., 2006. Oligocene-early Miocene transgressive cover of the Betic-Rif Internal Zone. Revision of its geologic significance. Eclogae Geol. Helv. 99, 237–253. Silva, P.G., Harvey, A.M., Zazo, C., Goy, J.L., 1992. Geomorphology, Depositional style and Morphometric relationships of Quaternary alluvial fans in the Guadalentin Depression (Murcia, Southeast Spain). Z. Geomorphol. 36 (3), 325–341. Torres, T., Llamas, J.F., Canoira, L., Coello, J., García-Alonso, P., Ortiz, J.E., 2000. Aminostratigraphy of two marine sequences from the Mediterranean coast of Spain. Cabo de Huertas (Alicante) and Garrucha (Almería). In: Goodfriend, G.A., Collins, M.J., Fogel, M.L., Macko, S.A., Wemiller, J.F. (Eds.), Perspectives in Amino Acid and Protein Geochemistry. Oxford University Press, New York, pp. 263–278. Tubía, J.M., 1985. Estructura de los Alpujárrides occidentales: cinemática y condiciones de emplazamiento de las peridotitas de Ronda. PhD Thesis. Bol. Geol. Min. 99. Univ. País Vasco (2, 3, 4 and 5).