Patterns and Average Rates of Late Neogene–Recent Uplift of the Betic Cordillera, SE Spain

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Geomorphology 50 (2003) 3–26 www.elsevier.com/locate/geomorph

Patterns and average rates of late Neogene–Recent uplift of the Betic Cordillera, SE Spain

Juan C. Braga a,*, Jose´ M. Martı´n a, Cecilio Quesada b

aDepartamento de Estratigrafıá y Paleontologıá, Facultad de Ciencias, Universidad de Granada, Campus de Fuentenueva s.n. 18002 Granada, Spain bIGME/Direccioń de Geologıá, Rıós Rosas 23, 28003 Madrid, Spain Received 1 September 2000; received in revised form 1 May 2001; accepted 15 July 2002

Abstract

The facies distribution in the sedimentary units infilling a series of Neogene basins has been used to reconstruct the relief generation and uplift across the Internal Zone of the Betic Cordillera in southern Spain. Uplift amounts and average rates can be estimated using the current elevation of the outcrops of well-dated deposits indicative of ancient sea-level positions. Coral reefs and coastal conglomerates record the initial development of emergent Betic relief during the Langhian. Continental and marginal marine deposits indicate the existence of a large island centred on the present Sierra Nevada–Sierra de los Filabres chain by the end of the Middle Miocene. The precursor of the Sierra Nevada–Sierra de los Filabres chain, originally part of this large island, remained emerged whilst the surrounding areas were re-invaded by the sea during the early Tortonian. At the end of the Tortonian the inland basins (Granada and Guadix basins) became continental, while the Sierras de la Contraviesa, Sierra de Ga´dor and Sierra Alhamilla emerged, separating the Albora´n Basin from the Alpujarra, Tabernas and Sorbas basins, which became narrow passages of the Mediterranean Sea. In contrast, the Sierra Cabrera emerged during the late Messinian, suggesting a progressive uplift from west to east of the sierras south of the Sierra Nevada–Sierra de los Filabres chain. During the Pliocene, only the low areas closest to the present-day coast remained as marine basins and progressively emerged throughout this stage. The highest average uplift rate recorded is 280 m/Ma for the Sierra de Ga´dor, although the average uplift rates of upper-Neogene coastal marine rocks since depositon have maximum values of approximately 200 m/Ma. Most of the uplift of the Betic mountains took place before the early Pliocene. The recorded uplift of Neogene rocks was highest at the margins of western Sierra Nevada, where peaks higher than 3000 m occur. The average rates of uplift were lower to the east of this major relief. The main sierras and depressions in the present-day landscape correspond respectively to the emergent land, in which uplift was concentrated, and to the marine basins that existed before the final emergence of the region. The altitude of the sierras reflects the time at which they became emergent, the highest mountains being the first to rise above sea level. D 2002 Elsevier Science B.V. All rights reserved.

Keywords: Uplift; Late Neogene; Palaeogeography; Betic Cordillera; SE Spain

1. Introduction * Corresponding author. Fax: +34-958-248528. E-mail addresses: [email protected] (J.C. Braga), [email protected] This is a study of the long-term landscape develop- (J.M. Martı´n), [email protected] (C. Quesada). ment of the Internal Zone of the Betic Cordillera in

0169-555X/02/$ - see front matter D 2002 Elsevier Science B.V. All rights reserved. PII: S0169-555X(02)00205-2 4 J.C. Braga et al. / Geomorphology 50 (2003) 3–26 southern Spain (Fig. 1) as recorded by the sediments conditions prevailing in the modern landscape (Har- which have infilled the Neogene basins that formed vey, 2001). and evolved as the Betic mountains were emerging Within this paper, we describe the palaeogeo- and rising. The modern topographic configuration of graphic evolution of the area during the late Miocene southern Spain consists of a series of mountain and Pliocene as deduced from the spatial distribution ranges, with peaks higher than 3000 m in the Sierra of coastal marine deposits from successive time slices. Nevada, separated by depressions. The late-Neogene We also quantify the amounts and average rates of uplift history and sedimentary evolution of the region uplift since their deposition for rocks formed in largely pre-determined the present-day landscape, coastal environments at the basin margins. since the major extant ranges (sierras) and depressions Previous attempts to quantify relief generation in are the direct counterparts of the earlier emergent the Betic mountains are either localised to a specific basement highs and the intervening marine basins area (e.g. Weijermars et al., 1985) or focus only on the respectively. The general emergence of the region Plio/Quaternary evolution of the region (Mather, resulted in a change from marine to continental 1991; Viseras, 1991; Stokes, 1997; Garcia, 2001). deposition in the basins and, during the Quaternary, Several other papers have addressed the timing and continued uplift caused a switch to the net erosional amount of the exhumation of the metamorphic com-

Fig. 1. Geological schematic map of southeastern Spain. Unless specified, the basins are named after the main town in them. J.C. Braga et al. / Geomorphology 50 (2003) 3–26 5 plexes in the Internal Zone of the Betic Cordillera (i.e. Permian basement (Lonergan, 1993; Martıń-Martıń, Zeck et al., 1992; Johnson et al., 1997; Lonergan and 1996). Johnson, 1998; Platt and Whitehouse, 1999). These The upper Nevado–Fila´bride tectonic unit (Mulha- papers focus mainly on the tectonometamorphic evo- ceń Nappe, Puga, 1976) and the Alpuja´rride complex lution of the basement rocks following their exhuma- were affected by high-pressure metamorphism due to tion during the Early and Middle Miocene. In crustal thickening as a result of the convergence of the contrast, we concentrate on the growth of the Betic African and Eurasian plates. The radiometric dates mountains after the emplacement of the Betic meta- constraining the high-pressure metamorphism in the morphic complexes to shallow crustal levels. Nevado–Fila´bride Complex indicate that convergence The study area is limited to the central-eastern began at about 51 Ma (Monie´ et al., 1991), although portion of the Betics, roughly spanning the provinces earlier dates have also been suggested (De Jong, of AlmerıáandGranada(Fig. 1),inwhichthe 1991). A sharp decompression in the metamorphic stratigraphy, facies distribution and age of the deposits P–T path of the Nevado–Fila´bride and Alpuja´rride in the Neogene basins are well constrained. The late complexes (Vissers, 1981; Go´mez-Pugnaire and Fer- Neogene uplift history of the Cabo de Gata volcanic nańdez-Soler, 1987; Bakker et al., 1989; Garcıá-Casco province, along the major Carboneras strike-slip fault and Torres-Roldań, 1996) suggests rock exhumation system, is treated separately in another paper (Martıń due to crustal-scale extension during the Early and et al., 2003, although some references to Cabo de Gata Middle Miocene (Monie´ et al., 1991; Garcıá-Duenãs et and the External Zone are made below. al., 1992; Watts et al., 1993; Comas et al., 1999; Platt and Whitehouse, 1999). Thinning of the previously thickened crust took place (Platt and Vissers, 1989) as 2. Regional setting a result of the extension. The Mala´guide complex did not undergo Alpine metamorphism and, consequently, 2.1. Basement geology was probably never subducted (De Jong, 1991). The present contact with the underlying Alpuja´rride Com- The Betic Cordillera in southern Spain is the plex is marked by a thick mylonitic zone cut by normal westernmost segment of the European Alpine belt. faults (Aldaya et al., 1991). This cordillera has traditionally been subdivided into an External Zone and an Internal Zone (Fig. 1). The 2.2. Neogene basins External Zone represents the Mesozoic to Middle Miocene southern continental margin of the Iberian The Betic Neogene basins developed on both the Massif, which was divided by rifting into different Internal and the External Zones and underwent defor- domains (Garcıá-Hernańdez et al., 1980; Vera 1988). mation and were uplifted as they filled with sediments The Prebetic constitutes the external domain where (Sanz de Galdeano and Vera, 1992). Consequently, the continental and shallow-marine sedimentation pre- configuration, limits and sedimentary dynamics of vailed from the Triassic to the Middle Miocene, while each basin changed considerably over time, reflecting the Subbetic, to the south, became a pelagic basin both the regional and local tectonic evolution. A during the Early Jurassic. major basin, the Guadalquivir Basin, developed at The Internal Zone consists of three stacked com- the cordillera front and was open to the Atlantic plexes that, in ascending order, are the Nevado– Ocean. The intermontane basins located on the Exter- Fila´bride, Alpuja´rride and Mala´guide (Fig. 1). The nal Zones are either continental (Prebetic basins) or Nevado–Fila´bride Complex comprises Palaeozoic or marginal embayments of the Guadalquivir Basin and older (Go´mez-Pugnaire et al., 2000) metamorphic as such related to the Atlantic Ocean. The rest of the rocks. The Alpuja´rride tectonic units include a series intermontane basins of the cordillera were connected of Palaeozoic–Mesozoic metasediments (Delgado et to the Mediterranean Sea. Two main types of Medi- al., 1981; Martıń and Braga, 1987; Tubıá et al., 1992). terranean-linked basins can be distinguished. (a) Inner The Mala´guide complex consists of a non-metamor- basins (the most distant from the present-day Medi- phic Mesozoic to Cenozoic cover overlying a pre- terranean Sea) occur mainly at the contact between the 6 J.C. Braga et al. / Geomorphology 50 (2003) 3–26

External and Internal Zones. Although both the Gua- during the rest of the Miocene and, in some cases even dix-Baza and Granada basins belong to this type, we during the Pliocene, except for a short time-interval in have chosen the Granada Basin as the most represen- the Messinian during the so-called ‘‘Messinian Salin- tative example (Fig. 2). (b) Outer basins (the nearest ity Crisis’’ (Riding et al., 1998). to the present-day Mediterranean), such as the Vera, From the Middle-Miocene to the early Tortonian, Sorbas, Tabernas, and Almerı´a–Nı´jar, are located in the Mediterranean-linked basins evolved under crus- the Internal Zone. The Sorbas Basin has been selected tal-scale extension, as recorded by normal faults that as the representative example (Fig. 3). are well dated in the Albora´n Basin (Comas et al., The two types of Mediterranean-linked basins have 1992, 1999), while contractive deformation related to a similar sedimentary evolution up to the late Torto- wrench tectonics has prevailed since the late Tortonian nian. At the latest Tortonian–early Messinian, the (Comas et al., 1999). The interaction of strike-slip inner basins were isolated from the Mediterranean fault systems determines a complex pattern of trans- Sea and became continental (Vera, 2000). The outer tensive and transpressive local conditions (Keller et basins remained connected to the Mediterranean Sea al., 1995).

Fig. 2. Neogene stratigraphy of the Granada Basin at its eastern margin. This is representative of the Mediterranean-linked inner basins (modified from Braga et al., 1990). J.C. Braga et al. / Geomorphology 50 (2003) 3–26 7

Fig. 3. Neogene stratigraphy of the Sorbas Basin. This is representative of the Mediterranean-linked outer basins (modified from Martı´n and Braga, 1994).

2.3. Topography Guadix basins are separated by the Sierra Arana (1943 m) at the contact between the External and A series of mountain ranges, trending roughly Internal Zones of the cordillera (Fig. 1). Several ranges E–W and separated by basins, determine the top- of Mesozoic rocks of the External Zone extend north- ography of the study area. Sierra Nevada (Fig. 1) is wards to the Guadalquivir Basin at the cordillera front. the highest mountain range in southern Spain with The Alpujarra Corridor, a very narrow, E–W several peaks over 3000 m (3482 m in the Mulhace´n). trending Neogene basin, separates Sierra Nevada from This, together with the Sierra de los Filabres (2168 m) the Sierra de Lu´jar–Sierra de la Contraviesa–Sierra to the east, is the main outcrop of the lowest Betic de Ga´dor chain to the south. The Sierra de Lu´jar (1824 nappes. North of Sierra Nevada, the Granada and m) and the Sierra de la Contraviesa (1508 m) con- 8 J.C. Braga et al. / Geomorphology 50 (2003) 3–26 stitute a coastal range while the topography of the (b) Rocks of shallow-water marine origin deposited Poniente Basin descends gradually from the southern on inner platforms in depths of less than 30 m, foot of Sierra de Ga´dor (2236 m) to the Mediterranean mostly inner-platform limestones. The identifica- (Fig. 1). To the east of the Andarax valley, the tion of the palaeoposition of sea level with these Tabernas and Sorbas basins occupy the depression deposits which is affected by a methodological between the Sierra de los Filabres and the Sierra error of F 30 m. Alhamilla (1387 m)–Sierra Cabrera (960 m). The Almerı´a–Nı´jar Basin descends from the southern The age of these shallow-marine sediments is slope of the latter chain to the Mediterranean Sea usually well constrained with precise biostratigraphic delimited at its southeastern margin by the volcanic or stable-isotope data in time intervals of a few Sierra de Cabo de Gata (Fig. 1). hundred thousand years (100 ka). The elevation of specific shoreline-marker rocks of each time slice analysed gives the amount of rock 3. Methods uplift from sea level since their deposition at each locality. The current elevation, however, has been In this paper, we describe and quantify the regional corrected with available data on global sea-level scale, spatial and temporal pattern of relief generation position (Hardenbol et al., 1998) at the time of of the central sector of the Betic mountains during the formation of the studied rocks (Fig. 4). Average uplift late Neogene. The palaeogeographic evolution was rates were obtained by dividing the corrected eleva- deduced from the distribution of coastal deposits in tion by the estimated absolute age of the rocks. the successive upper Neogene sedimentary units fill- Methodological errors arise both from uncertainties ing the basins in the study area. Uplift rates were in the identification of the ancient shorelines and from calculated by using the time-averaged elevation of the time ranges of available age constraints. The upper Miocene and Pliocene coastal and marginal pattern for the amount of uplift of the coastal marine marine rocks above modern sea level. These rocks rocks of any studied time slice is indicative of the formed at the basin margins and were elevated above differential uplift within the region since the deposi- sea level as the basement highs and the region in tion of these rocks. general were uplifted. The minimum average uplift rate of the highest Two types of rocks have been used to estimate peaks can be estimated for the Sierra de Ga´dor, uplift amounts and rates: Sierra Alhamilla and Sierra Cabrera as the time of the emergence of these sierras above sea level can be (a) Coral-reef and beach deposits that allow the constrained with the stratigraphic record in the (palaeo)position of sea level at the outcrop nearby basins. The current elevation of the peaks is localities to be reconstructed with a margin of the result of the interaction between the uplift of the error of only a few metres (less than 10 m). sierras and accompanying erosion. The time-aver-

Fig. 4. The present-day elevation of shoreline-marker rocks of each time slice analysed (E) has been corrected with available data on global sea- level position (Hardenbol et al., 1998) at the time of formation of the studied rocks (S) to obtain the rock uplift since deposition (U). S can be negative. Average uplift rates (AUR) can be obtained by dividing the corrected elevation (U) by the estimated absolute age of the rocks (T). J.C. Braga et al. / Geomorphology 50 (2003) 3–26 9 aged current elevation of the highest peaks is there- Complex, but Alpuja´rride rocks were eroded as well fore the minimum average uplift rate since their (Barragań, 1997). emergence. To the north, Langhian shallow-water marine limestones were deposited on the platform that developed on the southern margin of the Iberian Massif, corre- 4. Neogene sedimentary record and sponding to the Prebetic, i.e., the northern domain of palaeogeographic evolution of the area the Betic External Zone. These shallow-water carbonates change southwards to slope and basinal marls The Neogene basins in southern Spain are filled by and mass-flow deposits (Comas, 1978; Geel et al., sedimentary units separated by unconformities. The 1992), thereby suggesting a complete disconnection facies distribution in coeval units from different basins between the Betic island(s) and the Iberian mainland is used here to reconstruct the palaeogeography of the by a deep-water trough (‘‘North Betic Straits’’, Geel et study area in successive time slices. The outcrops of al., 1992). the pre-upper Tortonian units are generally small and In the southern Granada Basin, the upper-Langhian disconnected, making an accurate reconstruction of shallow-marine deposits are overlain by a continental the paleogeography before the late Tortonian difficult. unit of red conglomerates, sandstones and silts (Fig. 2) The stratigraphic record and data quality is substan- that can be traced around Sierra Nevada (Rodrı´guez- tially better for younger deposits, and therefore, the Fernańdez, 1982). Flanking the Sierra de los Filabres, descriptions below focus on the palaeogeography of red-to-grey conglomerates overlying marine upper? the area during the deposition of the upper Tortonian, Langhian marls, older Neogene units or the basement uppermost Tortonian–lowermost Messinian, lower has been interpreted as alluvial and fan-delta deposits Messinian, upper Messinian and lower Pliocene sedi- (Kleverlaan, 1989; Doyle et al., 1996) (Fig. 3). The mentary units. red conglomerates extend southwards to the Sierras de la Contraviesa and Ga´dor (Rodrı´guez-Fernańdez et 4.1. Pre-Tortonian evolution al., 1990), Alhamilla and Cabrera (Montenat, 1990; Barragań, 1997), and northwards to the Sierra de las The progressive unroofing and erosion of Betic Estancias (Braga and Martıń, 1988) and Sierra de nappes is recorded by the lithological variety of clasts Baza (Soria, 1993), underlying later marine deposits incorporated in various types of mass-flow deposits in the basins. These continental deposits indicate the within lower Miocene pelagic sediments (Rodrı´guez- existence of a large emerged Betic upland (Fig. 5).In Fernańdez, 1982). However, the first evidence for the Granada Basin, micromammal fossils in the red emerging Betic basement highs is the occurrence of silts point to a Serravallian age (Martıń-Sua´rez et al., upper Langhian coral reefs and associated coastal 1993), but in general the age of the red conglomeratic conglomerates in the southern Granada Basin (Braga units is poorly constrained and a lowermost Tortonian et al., 1996a) and in the Vera Basin (Barragań, 1997). age, suggested by authors such as Montenat (1990) In the Granada Basin these deposits appear in a single and Doyle et al. (1996) at least for parts of the units, isolated outcrop near Murchas (Fig. 1), indicating the cannot be discarded, even though in most localities presence to the north of an emerged Betic island, they are overlain by lower Tortonian marine sedi- probably the precursor of the Sierra Nevada–La ments. To´rtola chain (Fig. 1). The nature of the clasts in the To the south of Sierra Alhamilla and Sierra Cab- conglomerates suggests that only the uppermost Betic rera, the Serravallian and lower-Tortonian deposits are complex in the area (the Alpuja´rride Complex) was pelagic marls (Serrano, 1990). Together with the exposed and eroded. The occurrence of Langhian occurrence of deep-water Serravallian deposits in the coral reefs in deposits from the Vera Basin points to southern External Zone (Subbetic domain, Soria, the existence of an emerged relief in the eastern part of 1993), this suggests that the red units formed on an the present-day Sierra de los Filabres as well. Most island separated from the Iberian mainland (Fig. 5). clasts in the associated conglomerates here come from The existence of such a large emergent Betic the uppermost basement complex, the Mala´guide upland by the end of the Serravallian–earliest Torto- 10 J.C. Braga et al. / Geomorphology 50 (2003) 3–26

Fig. 5. Serravallian–lowermost Tortonian? palaeogeography in southern Spain. Significant outcrops delineate the minimum extension of the emergent land. nian is in agreement with the timing of cooling to the western Sierra Nevada only the Alpuja´rride Com- near-surface temperatures of the rocks of the plex was exposed and eroded (Rodrı´guez-Fernańdez Nevado–Fila´bride Complex, as recorded by fission et al., 1990). tracks in zircon and apatite (Johnson et al., 1997). The age of this cooling is about 12 Ma in the Sierra de los 4.2. Early Tortonian Filabres, 11.7 Ma in eastern Sierra Nevada and about 9 Ma in western Sierra Nevada (Johnson et al., 1997). The continental/fan-delta Serravallian–lowermost- This variation in cooling age from east to west Tortonian red siliciclastic deposits are overlain by suggests that the unroofing of the Nevado–Fila´bride lower Tortonian, shallow-marine mixed bioclastic Complex progressed diachronously from east to west and siliciclastic deposits (Rodrı´guez-Fernańdez, (Johnson et al., 1997). This hypothesis is supported by 1982; Braga et al., 1990; Rivas et al., 1999) (Figs. 2 the provenance of clasts in the Serravallian conglom- and 3). Except for the Granada Basin, the outcrops of erates: whereas in the Sierra de los Filabres the these bioclastic rocks are disconnected, making palae- Nevado–Fila´bride Complex was already unroofed oenvironmental interpretation and dating difficult. and contributing clasts (Braga and Martıń, 1988),in Consequently, the palaeogeography of the study area J.C. Braga et al. / Geomorphology 50 (2003) 3–26 11 cannot be reconstructed for the early Tortonian with los Filabres chain in scattered outcrops on the south- the same confidence as for later intervals. ern margins of the Tabernas, Sorbas and Vera basins. Lower Tortonian carbonate platforms rim the La The Alpuja´rride provenance of the clasts suggests To´rtola–Sierra Nevada–Sierra de los Filabres chain they derived from locally emergent reliefs at the (Rodrı´guez-Fernańdez, 1982), suggesting that this location of the modern Sierra Alhamilla and Sierra chain remained emergent during the early Tortonian. Cabrera. Coastal volcaniclastic and bioclastic deposits Terrigenous material shed from upland fed localised point to the existence of emergent volcanic highs in fan deltas around Sierra Nevada. The clasts in these the Cabo de Gata volcanic province at this time fan deltas indicate that the Alpuja´rride Complex was (Braga et al., 1996b; Betzler et al., 1997). still the only basament complex at the surface in the North of the La To´rtola–Sierra Nevada–Sierra de western Sierra Nevada (Rodrı´guez-Fernańdez, 1982; los Filabres chain, shallow-water platforms with car- Martıń and Braga, 1997) (Fig. 6). bonate sedimentation extended over both Internal and Lower Tortonian shallow-marine deposits occur External Zone substrates. Several Subbetic upland south of the La To´rtola–Sierra Nevada–Sierra de areas were already emerged (Rodrı´guez-Fernańdez,

Fig. 6. Erosion pulses of western Sierra Nevada and stratigraphic architecture of the corresponding conglomerate units (modified from Martı´n and Braga, 1997). 12 J.C. Braga et al. / Geomorphology 50 (2003) 3–26

1982) and islands rimmed by shallow-water marine (Martıń and Braga, 1997; Fig. 6). Coral reefs devel- platforms replaced the former deep-water trough in oped on these fan deltas and on the shelves rimming the North Betic Straits (Soria, 1993). However, the the emergent uplands, thus allowing the upper Torto- lack of accurate dating and sedimentological analysis nian palaeogeography to be accurately traced (Esteban of the shallow-water deposits makes reconstructing et al., 1996).LaTo´rtola remained as an island (Braga the precise palaeogeography of the External Zone at et al., 1990) and the main relief was the Sierra this time a difficult task. The Iberian mainland Nevada–Sierra de los Filabres chain, which merged expanded southwards by the partial emersion of the with the extensively emergent External Zone to the Prebetic domain, on which shallow-marine sedimen- north (Rodrı´guez-Fernańdez, 1982; Soria, 1993; Soria tation is restricted to the southernmost areas. et al., 1999). The northern coasts of the marine Granada and Guadix basins were rimmed by coral 4.3. Late Tortonian reefs as well (Fig. 7). By the end of the late Tortonian, most of the Subbetic and Prebetic areas formed a Upper Tortonian deposits in the Neogene basins in continuous mainland with the Iberian Massif (Soria et the study area comprise proximal deltaic siliciclastic al., 1999; Fig. 7). The Guadalquivir basin was still sediments and carbonates that include coral reefs. open to the Atlantic and the Guadix basin was con- These proximal deposits pass laterally to distal marls, nected to the east with the main Mediterranean by the silty marls and turbidite sandstones and conglomer- Almanzora corridor. Some fan deltas developed in this ates (Martıń et al., 1989; Braga et al., 1990; Martıń corridor, probably reflecting a pulse in the uplift of the and Braga, 1994) (Figs. 2 and 3). The distribution of Sierra de los Filabres. The northern coast of the reef- these upper Tortonian deposits indicates that a narrow fringed Almanzora corridor (Martıń et al., 1989) was platform with coral reefs and localised fan deltas formed by an Internal Zone high (Sierra de las rimmed the southern margin of the Sierra Nevada– Estancias), probably continuous with the above-men- Sierra de los Filabres chain (Martıń and Braga, 1996), tioned emergent External Zone. but to the south of this main chain deep-water marine basins developed in areas that had been emergent 4.4. Latest Tortonian–earliest Messinian during the early Tortonian and at the end of the Middle Miocene (Fig. 7). Upper Tortonian marls Uppermost Tortonian–lowermost Messinian rocks and turbidites were deposited on top of the continental in the Granada and Guadix basins consist of fluviatile conglomeratic and shallow-marine bioclastic units in conglomerates, sandstones and silts with lacustrine the Alpujarra, Tabernas, Sorbas and Vera basins clays and evaporites (Dabrio et al., 1982; Martıń et al., (Rodrı´guez-Fernańdez et al., 1990; Weijermars et al., 1984; Soria et al., 1999; Garcıá-Aguilar and Martıń, 1985; Kleverlaan, 1989), which were laterally con- 2000; Fig. 2). In the basins south of the Sierra nected at that time. Pelagic sediments encroach the Nevada–Sierra de los Filabres, proximal deposits of sides of present-day sierras south of these basins, such this age comprise bioclastic carbonates with various as the Contraviesa, Ga´dor, Alhamilla and Cabrera. proportions of siliciclastic grains (Fig. 3) and local These sierras have no shallow-water deposits around fan-delta conglomerates (Rodrı´guez-Fernańdez et al. them, indicating that they were not emergent (Fig. 7). 1990; Martıń and Braga, 1994), except for the Taber- Nevertheless, current direction and sedimentary body nas Basin in which only siliciclastic fan deltas occur geometries suggest the existence of submarine swells (Kleverlaan, 1989). All these shallow-water materials at the modern location of the sierras (Haughton, 1994, pass laterally to distal marls and turbidite conglom- 2000). Deep-water marine sedimentation extended erates and sandstones (Kleverlaan, 1989; Haughton, southwards to the Almerıá–Nı´jar (Serrano, 1990) 1994; Braga et al., 2001). The geographical distribu- and Alborań basins (Comas et al., 1996). tion of the deposits from this time interval indicates The Nevado–Fila´bride Complex was unroofed and that at the end of the Tortonian, the Granada, Guadix subjected to erosion, providing clasts incorporated in and Almanzora basins were uplifted and became fan-delta conglomerates deposited around the Sierra continental basins with fluviatile and lacustrine sed- Nevada for the first time, especially at its western end imentation. The Sierra de la Contraviesa, Sierra de J.C. Braga et al. / Geomorphology 50 (2003) 3–26 13

Fig. 7. (A) Upper Tortonian palaeogeography of southern Spain. (B) Enlarged schematic map of the study area showing the outcrops of reefs and other coastal deposits of this age (modified from Esteban et al., 1996).

Ga´dor and Sierra Alhamilla were also uplifted and the Vera and Almerı´a–Nı´jar basins (Fig. 8A and B). emerged, restricting the marine basins to the south of Re-folding of the Betic basement units by crustal the Sierra Nevada–Sierra de los Filabres as a narrow shortening and isostatic uplift has been suggested as E–W corridor open to the Albora´n Basin through the the most likely mechanism to explain the emergence Andarax Corridor and to the Mediterranean through of Sierra Alhamilla at the end of the Tortonian 14 J.C. Braga et al. / Geomorphology 50 (2003) 3–26

Fig. 8. (A) Uppermost Tortonian–lowermost Messinian palaeogeography of southern Spain. (B) Enlarged schematic map of the study area. (C) Lower Messinian palaeogeography of SE Spain. (D) Upper Messinian palaeogeography of SE Spain. Note the progressive emergence of the sierras and surrounding areas in the region from west to east during the Messinian (B–C).

(Weijermars et al., 1985). In the Cabo de Gata area 4.5. Early Messinian (pre-evaporitic) several volcanic highs, including recently formed volcanic domes, were also emergent (Martıń et al., Lower Messinian marine deposits are restricted to 1996; Betzler et al., 2000). the SE Betic Neogene basins. In the study area, they J.C. Braga et al. / Geomorphology 50 (2003) 3–26 15 occur in the Tabernas, Sorbas, Vera, Poniente and 1998), but the area of marine sedimentation was more Almerıá–Nı´jar basins. Proximal sediments of this age restricted compared to previous periods. Evaporites, consist of two successive reef units characterised mainly gypsum, formed in the first phases of sea-level respectively by bioherms and fringing reefs with recovery. As the sea level rose, conglomerates, sand- associated calcarenites and calcirudites (Riding et stones, oolites, stromatolites and coral patch-reefs al., 1991; Martıń and Braga, 1994; Fig. 3). Bodies formed on top of the previous lower Messinian reef of deltaic siliciclastic deposits occur locally among platforms (Fig. 3; Dabrio et al., 1985; Martıń et al., these carbonates (Braga and Martıń, 1996). Both reef 1993). These proximal deposits change basinwards to units change laterally to silty marls, marls and turbi- silts and silty marls with turbidite intercalations (Mar- dite conglomerates and sandstones (Fig. 3). As before, tıń et al., 1993; Aguirre and Sańchez-Almazo, 2000). siliciclastic deposits prevailed in the Tabernas Basin During this period, a N–S high separated the Taber- (Kleverlaan, 1989; Haughton, 2000). The location of nas and Sorbas basins. The Sierra Cabrera remained lower Messinian reef outcrops suggests a landward as a submerged swell during the early Messinian with displacement of the palaeocoast around the Sierra no evidence of shallow-water sedimentation around it Nevada–Sierra de los Filabres that could be the result (Braga et al., 2001) and emerged in the late Messinian of the global eustatic sea-level rise recorded during to separate the open-marine Vera Basin from the the early Messinian (Haq et al., 1987). Uplift none- restricted evaporitic Almerıá–Nı´jar Basin to the south theless continued in the Sierra de Ga´dor and Sierra (Riding et al., 1998; Fig. 7D). Alhamilla, both of which expanded to displace the palaeocoast radially from the sierra axes. The western 4.7. Early Pliocene part of the Alpujarra corridor was also uplifted, restricting the marine basin to its easternmost part as During the early Pliocene, marine sedimentation the emergent areas in the Sierra de la Contraviesa– took place only in the basins closest to the present- Sierra de Ga´dor chain merged with the Sierra Nevada day Mediterranean: the Poniente, Almerıá–Nı´jar and (Fig. 8C). In the Cabo de Gata, a re-arrangement of Vera basins, except for a brief sea invasion of the the volcanic highs produced changes in the palaeo- already continental Sorbas Basin (Mather, 1991). geography of the area (Braga et al., 1996b). The lower Pliocene proximal deposits in these basins include mostly conglomerates and sandstones, with 4.6. Late Messinian variable proportions of bioclastic material and calcarenites locally. These coarse-grained sediments After the desiccation of the Mediterranean related change laterally and prograde over distal silts and to the ‘‘Messinian Salinity Crisis’’ and before the end silty marls (Fortuin et al., 1995; Stokes, 1997; of the Messinian, the sea re-invaded the Tabernas, Aguirre, 1998). The emergence of the eastern portion Sorbas, Vera and Almerıá–Nı´jar basins (Riding et al., of the Alpujarra corridor and the eastern part of the

Fig. 9. Lower Pliocene palaeogeography of southeastern Spain (modified from Aguirre, 1998). 16 J.C. Braga et al. / Geomorphology 50 (2003) 3–26

Fig. 10. Altitude in metres of the outcrops of lower Tortonian inner-platform deposits in the study area. Contour interval, 100 m. A few contours have been suppressed for clarity.

Fig. 11. Altitude in metres of the outcrops of upper Tortonian reefs and other coastal deposits in the study area. Contour interval, 100 m. A few contours have been suppressed for clarity. J.C. Braga et al. / Geomorphology 50 (2003) 3–26 17

Tabernas basin concentrated the southern siliciclastic and Poniente basins were still covered by the sea, discharge from the Sierra Nevada–Sierra de los forming a shallow bay (Aguirre, 1998). Filabres in a delta located between the Sierra de As mentioned above, the Granada and Guadix Ga´dor and Sierra Alhamilla and open to the Alme- basins have been continental since the latest Torto- rıá–Nı´jar Basin (Postma, 1983) (Fig. 9). The vol- nian. The source of the conglomerate clasts and the canic relief of the Cabo de Gata was almost locations of alluvial fans suggest a widening of the completely emerged except for small embayments Sierra Nevada relief during the early Pliocene (Martıń of the Mediterranean Sea, such as the Carboneras and Braga, 1997) (Fig. 6). During the late Pliocene and Agua Amarga basins (Aguirre, 1998).The and Pleistocene, a later denudation phase associated coarse-grained clastics produced by their erosion with the eastern part of Sierra Nevada is recorded in accumulated in a delta discharging into the Alme- the Guadix Basin (Garcıá-Aguilar and Martıń, 2000) rıá–Nı´jar basin (Boorsma, 1992, 1993) (Fig. 9). and the emergent Tabernas Basin (Kleverlaan, 1989). At the end of the early Pliocene, a regression in all the marine basins in the area resulted in a progressive withdrawal of the sea. The palaeogeography during 5. Uplift amounts and average rates the late Pliocene, probably after an uplift pulse (Aguirre, 1998), was quite similar to the present day We report here the amount and average rate of and only the southernmost areas of the Almerıá–Nı´jar uplift of shoreline-marker rocks of the analysed time

Fig. 12. Altitude in metres of the outcrops of uppermost Tortonian–lowermost Messinian inner-platform deposits in the study area. Contour interval, 100 m. A few contours have been suppressed for clarity. 18 J.C. Braga et al. / Geomorphology 50 (2003) 3–26 slices since the early Tortonian. The current elevation considered the minimum uplift value of Sierra Nevada corrected with the known values of global sea-level since the early Tortonian (Fig. 10). According to position at the time of deposition (amount of rock Brachert et al. (1996), these platform deposits prob- uplift) of outcrops of rocks of the succesive units is ably formed during the global sea-level lowstand plotted in Figs. 10–14. The contours indicate points separating cycles TB3.1 and TB3.2 of Haq et al. of estimated similar uplift since the formation of the (1987). The estimated global sea level at that low- rocks. The absolute age range of the rocks of each stand was about 10 m lower than at the present-day analysed time slice is discussed and then used to (Hardenbol et al., 1998). This difference in sea level obtain the average uplift rate since deposition. is lower than our methodological error in estimating In the case of the Sierra Nevada–Sierra de los sea-level position by inner-platform facies distribu- Filabres chain, uplift rates can be estimated only for tion and is a negligible percentage of the present-day the surrounding basin margins, since the altitude that altitude of the lower-Tortonian outcrops in the study had been reached by the major Middle Miocene area. upland area when the lower Tortonian shallow-marine The elevation values for the lower Tortonian inner- sedimentation started is unknown. The subsequent platform deposits decrease in very steep gradients uplift history of the spine of the sierras is also poorly towards the Granada and Valle de Lecrı´n depressions constrained. (Fig. 10). Lower Tortonian shallow-water deposits in Sierra de la To´rtola crop out up to 1380 m, defining a 5.1. Lower Tortonian rocks highly elevated area separated from Sierra Nevada (Fig. 10). In the eastern part of the Sierra Nevada– Outcrops of lower Tortonian inner-platform depos- Sierra de los Filabres chain, the maximum height of its reach their maximum elevations in the western and lower Tortonian inner-platform deposits always northwestern margins of the Sierra Nevada and in the remains below 870 m, suggesting a general eastward Sierra Arana, with altitudes of up to 1830 m (Sanz de decrease of the Sierra Nevada–Sierra de los Filabres Galdeano and Lo´pez-Garrido, 1999), which can be average uplift since the early Tortonian.

Fig. 13. Altitude in metres of the outcrops of lower Messinian reefs in the study area. Contour interval, 100 m. A few contours have been suppressed for clarity. J.C. Braga et al. / Geomorphology 50 (2003) 3–26 19

Fig. 14. Altitude in metres of the outcrops of lower Pliocene inner-platform deposits in the study area. Contour interval, 100 m. A few contours have been suppressed for clarity.

The lower Tortonian mixed siliciclastic and bio- et al. (1993), dated at 7.5 Ma (Krijgsman et al., 1997), clastic materials considered here formed after the is recorded almost at the top of this unit in the Sorbas appearance of N. acostaensis (Rivas et al., 1999) Basin (Sańchez-Almazo, 1999). Upper Tortonian dated at 10.9 Ma (Berggren et al., 1995) and before reefs, therefore, formed approximately in the time the first occurrence of N. humerosa (Martıń-Pe´rez, interval from 8.5 to 7.5 Ma. According to Esteban 1997) at 8.5 Ma (Berggren et al., 1995). The most et al. (1996) and Brachert et al. (1996), this upper accurate estimate for the age of these deposits is the Sr Tortonian reef unit can be correlated with the high- isotopic age of approximately 9.2 Ma determined in stand of TB3.2 cycle of Haq et al. (1987), which Sierra Alhamilla by Hodgson (2002). This age value reached a sea level about 30 m above the present-day implies maximum average uplift rates since the early one (Hardenbol et al., 1998). Tortonian (for the deposits at the western Sierra The maximum altitudes of outcrops of upper Tor- Nevada margin) of up to 200 m/Ma (Fig. 15A). tonian reef and other coastal sediments are concentrated at the western and northwestern margins of 5.2. Upper Tortonian rocks Sierra Nevada and southeastern Sierra Arana, with a rapid decrease in values towards the Granada depres- The first occurrence of N. humerosa (8.5 Ma, sion away from the Sierra Nevada (Fig. 11).La Berggren et al., 1995) is in the fine-grained materials To´rtola stands out as an area of highly elevated upper at the bottom of the upper Tortonian reef unit in the Tortonian reef outcrops isolated from the Sierra Granada Basin and in the Almanzora Corridor Nevada. As in the underlying sedimentary unit, max- (Guerra-Merchań and Serrano, 1993; Martıń-Pe´rez, imum outcrop elevation generally decreases towards 1997). The Planktonic Foraminifer Event 1 of Sierro the eastern Sierra Nevada–Sierra de los Filabres 20 J.C. Braga et al. / Geomorphology 50 (2003) 3–26

Fig. 15. (A) Maximum average uplift rates since formation of the coastal rocks from the lower Tortonian to the lower Pliocene in SE Spain. (B) Minimum average uplift rates of the highest peaks in Sierra de Ga´dor, Sierra Alhamilla and Sierra Cabrera. Rates correspond to m/Ma. Shaded segments in the time scale correspond to the constrained interval of formation for the studied units.

chain. In some areas, such as to the north and north- margin and La To´rtola, significant uplifts of one to west of Granada, the similarity in altitude of the lower several hundred metres are recorded from 9 to 7.5 Ma. and upper Tortonian deposits indicates that almost no The maximum average rate of uplift estimated for uplift took place at those basin margins between the the upper Tortonian coastal sediments since their formation of the two sedimentary units, except per- formation is approximately 150 F 10 m/Ma (Fig. haps for the several tens of metres needed to com- 15A). This value for the reefs in La To´rtola and the pensate for global sea-level rise between the formation western Sierra Nevada and Sierra Arana margins of the lower and upper units. These areas were, contrasts strongly with the much lower rates of 60 therefore, mostly uplifted during the last 7.5 Ma. In m/Ma estimated for the outcrops in the Alpujarra and other regions, such as the western Sierra Nevada the eastern Almanzora corridors. J.C. Braga et al. / Geomorphology 50 (2003) 3–26 21

5.3. Uppermost Tortonian–lowermost Messinian of Sierra Alhamilla have uplifted at much lower rates rocks (from 100 to 40 m/Ma).

The uppermost Tortonian–lowermost Messinian 5.4. Lower Messinian rocks bioclastic carbonates were deposited after 7.5 Ma (datum recorded in the underlying unit). These shal- The Messinian reefs were coeval with the Plank- low-water carbonates change laterally and upwards to tonic Foraminifer Event 4 of Sierro et al. (1993, dated marls and silty marls in which the first occurrence of at 6.36 Ma by Krijgsman et al., 1997) recorded in the Globorotalia mediterranea (dated at 7.2 Ma, Krijgs- lower reef unit (Braga and Martıń, 1996), continuing man et al., 1997) has been recorded (Sierro et al., until the end of the pre-evaporitic Messinian marine 1993). An absolute age of 7.2 F 0.2 Ma is considered sedimentation dated at 5.9 Ma in the Sorbas Basin the best estimate for this sedimentary unit, which (Gautier et al., 1994; Krijgsman et al., 1999). The pre- probably formed during the lowstand separating evaporitic Messinian reefs in the basins of southeast- cycles TB3.2 and TB3.3 of Haq et al. (1987) (Martıń ern Spain therefore grew from approximately 6.4 to and Braga, 1994; Brachert et al., 1996). The global 5.9 Ma, during the highstand of Cycle TB3.3 of Haq sea level was only 5 m lower than today (Hardenbol et et al. (1987) (Martıń and Braga, 1994; Brachert et al., al., 1998), which makes a negligible difference to the 1996). The highest sea level in this highstand was uplift-rate estimates for this sedimentary unit. about 40 m above present-day sea level (Hardenbol et The uppermost Tortonian–earliest Messinian shal- al., 1998). Sea-level oscillations have been recorded low-water carbonates formed in the southeastern Betic within the Messinian reef units (Goldstein and basins in areas which had yet to emerge by the late Franseen, 1995; Braga and Martıń, 1996), but reefs Tortonian. The maximum altitudes of the inner-plat- at the highest altitudes in each outcrop area probably form carbonate outcrops of this age can be found in formed at the peak of the global highstand. the Sierra de Ga´dor at ca. 1600 m (Fig. 12). The The Messinian reefs crop out several tens of metres elevation of the outcrops decreases radially outwards higher than the previous bioclastic-carbonate unit at the from the centre of the sierra. Outcrop altitude likewise Sierra de los Filabres margin (Fig. 13). This increase in decreases away from the margins of Sierra de la elevation is mostly the result of a global sea-level rise Contraviesa, Sierra Alhamilla and Sierra de los Fila- between the formation of the two units, implying that bres to the surrounding depressions. In addition, a the margin of Sierra de los Filabres was essentially general decrease in elevation of the inner-platform stable from 7.2 to 5.9 Ma and no substantial uplift of the outcrops of this unit from the Sierra de Ga´dor to the area took place during that time interval. In contrast, the east can also be recognised. The lowest outcrops in northeastern margin of the Sierra Alhamilla was prob- the study area occur in the Vera Basin at the eastern ably uplifted some tens of metres since the uppermost end of Sierra de Filabres (Fig. 12). Tortonian–lowermost Messinian bioclastic carbonates The Sierra de Ga´dor was not emergent during the crop out several tens of metres higher than the Messi- deposition of the upper-Tortonian reef unit (Fig. 7). nian reefs. Discounting the additional 40 m in the The highest peak of the sierra (2126 m) has therefore global sea level compared to the present day, maximum been uplifted over the last 7.5 Ma with a minimum average uplift rates of the reef outcrops have been average rate of 280 m/Ma (Fig. 15B). The highest 110 F 5 m/Ma (Fig. 15A). Present-day Messinian reef outcrops of uppermost Tortonian–lowermost Messi- altitudes (Fig. 13) and the corresponding uplift rates nian carbonates in the sierra rose at an average rate of decrease towards the eastern Sierra de Filabres and 220 F 5 m/Ma over the last 7.2 F 0.2 Ma (Fig. 14A). towards the depression of the Almerıá–Nı´jar Basin Likewise, the Sierra Alhamilla emerged after the away from Sierra de Ga´dor and Sierra Alhamilla. deposition of the upper-Tortonian reef unit (Figs. 7 and 8A,B) and its highest peak (1387 m) was uplifted 5.5. Upper Messinian at a minimum average rate of 180 m/Ma (Fig. 15B). The areas with outcrops of uppermost Tortonian– After the desiccation of the Mediterranean related lowermost Messinian carbonates at the eastern margin to the ‘‘Messinian Salinity Crisis’’ and evaporite 22 J.C. Braga et al. / Geomorphology 50 (2003) 3–26 formation, sea level recovered and the remaining lations inside the lower Pliocene sea-level cycles, marine basins in SE Spain were re-flooded at the prevent any confident conclusion. end of the Messinian (Riding et al., 1998) (Fig 8D). The first sedimentary evidence of the emergence of the Sierra Cabrera is coeval with gypsum deposition 6. Concluding remarks in the Sorbas and Almerıá–Nı´jar basins, which took place approximately 5.5 Ma ago (Riding et al., 1998, The palaeogeographic evolution of the Internal 1999). The highest peak in Sierra Cabrera (961 m) has Zone of the Betic Cordillera from the end of the been uplifted at a minimum average rate of 170 m/Ma Middle Miocene to the Pliocene can be summarised since then (Fig. 15B). as follows: –There was a large island at the end of the Middle 5.6. Lower Pliocene rocks Miocene, which records the initial uplift of the present-day highest peaks in the Betic Cordillera, The marine sedimentation in the basins of south- the Sierra Nevada–Sierra de los Fila´bres chain (Fig. eastern Almerıá continued during the early Pliocene 5). The spine of this chain remained emergent for the and shallow-water platform deposits from this age rest of the Cenozoic but during the early Tortonian the can be used to estimate the uplift of the basin sea invaded the previously emergent southern part of margins since then. The lower Pliocene deposits in the Middle Miocene island on which the Alpujarra, the Almerıá basin formed from 5.2 to 3.6 Ma (Aguirre, Tabernas, Sorbas and Vera basins started to develop as 1998), which includes the highstand of the TB3.4 marginal basins connected to the Alborań Basin (Fig. cycle of Haq et al. (1987) with a highest sea level 7). some 90 m above the present-day level (Hardenbol et –These basins reached their maximum water depth al., 1998). during the late Tortonian and became narrow corridors The highest elevations of lower Pliocene inner- at the end of this interval, when the Sierra de la platform deposits are found in the Tabernas Basin Contraviesa, Sierra de Ga´dor and Sierra Alhamilla (620 m), decreasing southwards along the modern emerged (Fig. 8A,B). Andarax Valley depression (Fig. 14). High altitudes –Major uplift of the External Zone connected the of up to 540 m are concentrated around Sorbas while Betic islands to the Iberian mainland during the altitudes of up to 410 m are recorded in the Almerıá– Tortonian. In the latemost Tortonian, the inland Gran- Nı´jar basin, where outcrop elevation decreases south- ada and Guadix basins, together with the Almanzora wards away from Sierra Alhamilla and Sierra Cabrera. Corridor, became continental. This was the last episode of marine sedimentation in –The Sierra Cabrera emerged in the Late Messi- the Tabernas and Sorbas basins as they emerged above nian, suggesting a progressive uplift from west to east sea level soon afterwards. Taking into account that of the southern sierras (Sierra de la Contraviesa, Sierra global sea-level was up to 90 m higher during the de Ga´dor, Sierra Alhamilla and Sierra Cabrera) (Fig. early Pliocene than today, average uplift rates range 8A–D). between 70 and 100 F 20 m/Ma for the Sorbas Basin –During the Pliocene only the basins closest to the outcrops and up to 120 F 20 m/Ma for the Tabernas modern Mediterranean remained marine and progres- Basin (Fig. 15A). If we accept the above-mentioned sively emerged throughout this period (Fig. 9). figure of a lower Pliocene sea level 90 m higher than –The average rock uplift rates of upper–Neogene today, the Poniente area has subsided during the last coastal and shallow–water marine deposits in the 3.6 Ma, since all the lower Pliocene outcrops in the study area since their formation have maximum values area are below 80 m. Nonetheless, uncertainties intro- of approximately 200 m/Ma. The maximum average duced by the methodological error of estimating uplift rate calculated for a particular sierra since its palaeobathymetry ( F 30 m in the case of inner-plat- emergence is 280 m/Ma in the case of Sierra de Ga´dor. form deposits), together with the difficulties of estab- All these values lie well below the exhumation rates lishing the accurate timing of sediment formation in estimated for the of the Nevado–Fila´bride Complex the Poniente Basin in relation to the sea-level oscil- after metamorphism (500–700 m/Ma, Weijermars et J.C. Braga et al. / Geomorphology 50 (2003) 3–26 23 al., 1985) or during its cooling to near-surface temper- We are most grateful to Antonio Herrera (Parque atures by extensional tectonic unroofing. Johnson et Nacional de Sierra Nevada) for his assistance with al. (1997) proposed cooling rates of 105–200 jC/Ma fieldwork inside the Sierra Nevada Park. We also thank from 25 to 10 Ma, which may equal exhumation rates Christine Laurin for the revision of the English text. of 700–1400 m/Ma. Platt and Whitehouse (1999) This research has been carried out within the frame- obtained minumum exhumation rates of 6000 m/Ma work of IGCP 453 ‘‘Uniformitarism revisited: a from approximately 27–19 Ma for diverse Betic comparison of recent and ancient orogens’’. basement units. –A general fall of average uplift rates since deposition with time can be recognised: The average rates References since deposition are generally lower for younger units from the lower Tortonian to the lower Pliocene (Fig. Aguirre, J., 1998. El Plioceno del SE de la Penıńsula Ibe´rica 15A). The estimated average rates also imply that (provincia de Almerıá). Sıńtesis estratigra´fica, sedimentaria, most of the uplift of the Betic mountains took place bioestratigra´fica y paleogeogra´fica. Rev. Soc. Geol. Esp. 11, before the early Pliocene. 297–315. Aguirre, J., Sańchez-Almazo, I.M., 2000. Tempestite-to-turbidite –Since the early Tortonian, the regional uplift of deposition in post-evaporitic Messinian sediments of the Ga- the Betic complexes and the basins that developed on fares area (Almerıá, SE Spain). TTR-9 Post-Cruise Conference: them has been highest in the western Sierra Nevada Geological processes on European continental margins, Abstract (the location of present-day peaks higher than 3000 book, Granada, Spain, 7 pp. m) and the surrounding basin margins. The average Aldaya, F., Alvarez, F., Galindo-Zaldı´var, J., Gonza´lez-Lodeiro, J., Jabaloy, A., Navarro-Vila, F., 1991. The Mala´guide-Alpuja´rride rates of uplift since the formation of the analysed contact (Betic Cordilleras, Spain): a brittle extensional detach- sedimentary units has been progressively lower to the ment. Compt. Rend. Acad. Sci. Paris 313, 1447–1453. east (Figs. 10–14). Bakker, H.E., De Jong, K., Helmers, H., Biermann, C., 1989. The –The altitude reached and the implied uplift rates geodynamic evolution of the Internal Zone of the Betic Cordil- for the shoreline markers of any age also decrease leras (south-east Spain): a model based on structural analysis and geothermobarometry. J. Metamorph. Geol. 7, 359–381. away from the present-day sierras, where the uplift Barragań, G., 1997. Evolucioń geodina´mica de la Depresiońde was obviously greatest during the late Neogene his- Vera. Provincia de Almerıá. Cordilleras Be´ticas. PhD thesis, tory of relief generation (Figs. 10–14). Univ. Granada, Spain (unpublished), 698 pp. –The major sierras and depressions that dominate Berggren, W.A., Kent, D.V., Swisher III, C.C., Aubry, M.P. 1995. A the modern landscape directly correspond respec- revised Cenozoic geochronology and chronostratigraphy. In: Berggren, W.A., Kent, D.V., Aubry, M.P., Hardenbol, J. tively to the emergent land and marine basins during (Eds.), Geochronology Time Scales and Global Stratigraphic the palaeogeographical evolution before the progres- Correlation. Spec. Publ. Soc. Econ. Paleontol. Mineral. 54, sive emergence of the region. The altitude of the 129–212. sierras also reflects their age as emergent uplands, Betzler, C., Brachert, T.C., Braga, J.C., Martıń, J.M., 1997. Near- the highest mountains being the first to rise above shore, temperate, carbonate depositional systems (lower Torto- nian, Agua Amarga Basin, southern Spain): implications for sea level. carbonate sequence stratigraphy. Sediment. Geol. 113, 27–53. Betzler, C., Martıń, J.M., Braga, J.C., 2000. Non-tropical carbonates related to rocky submarine cliffs (Miocene, Almerıá, Southern Acknowledgements Spain). Sediment. Geol. 131, 51–65. Boorsma, L.J., 1992. Syn-tectonic sedimentation in a Neogene strike-slip basin containing a stacked Gilbert-type delta (CBB ´ JCB and JMM’s work was funded by the Fundacion subbasin, SE Spain); an example of basin formation under con- Ramon Areces, Project ‘‘Cambios clima´ticos en el sur stant stress conditions. Sediment. Geol. 81, 105–123. de Espanã durante el Neo´geno’’ and DGCYT Project Boorsma, L.J., 1993. Syn-tectonic sedimentation in a Neogene PB97-0809. We are very grateful to Juan Gonza´lez strike-slip basin (Serrata area, SE Spain). PhD thesis, Univ. Lastra (TECNA) for his technical support and advice Amsterdam, The Netherlands, 85 pp. Brachert, T.C., Betzler, C., Braga, J.C., Martıń, J.M., 1996. Record on the elaboration of altitude contour maps. We thank of climatic change in neritic carbonates: turnover in biogenic P. Haughton and L. Lonergan for their critical associations and depositional modes (late Miocene, southern comments that helped us to improve the manuscript. Spain). Geol. Rundsch. 85, 327–337. 24 J.C. Braga et al. / Geomorphology 50 (2003) 3–26

Braga, J.C., Martıń, J.M., 1988. Neogene coralline-algal growth- M., Ward, W.C., Rouchy, J.M. (Eds.), Models for Carbonate forms and their palaeoenvironments in the Almanzora river val- Stratigraphy from Miocene Reef Complexes of Mediterranean ley (Almerıá, S.E. Spain). Palaeogeog., Palaeoclimatol., Palae- Regions. Concepts in Sedimentology and Paleontology Series, oecol. 67, 285–303. vol. 5. SEPM, Tulsa, OK, pp. 55–72. Braga, J.C., Martıń, J.M., 1996. Geometries of reef advance in Fortuin, A.R., Kelling, J.M.D., Roep, T.B., 1995. The enigmatic response to relative sea-level changes in a Messinian (uppermost Messinian-Pliocene section of Cuevas del Almanzora (Vera ba- Miocene) fringing reef (Cariatiz reef, Sorbas Basin, SE Spain). sin, SE Spain) revisited. Erosional features and strontium iso- Sediment. Geol. 107, 61–81. tope age. Sediment. Geol. 97, 177–201. Braga, J.C., Martıń, J.M., Alcala´, B., 1990. Coral reefs in coarse Garcia, A.F., 2001. 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