In this sector Hoeppener et al. (1964), Dürr (1963), and Didon (1969) considered a unit, the Blanca unit (Fig. 2 A), as lying under the Ronda Peridotites, these being in turn overlaid by the Casares unit. However, Mollat (1968) and Buntfuss (1970) held that the Blanca unit in some places overlies the peridotites. Didon et al. (1973) defined the Federico-Casares units, situated above the Los Reales unit. This latter name, Los Reales, was used by Bourgois (1978) to indicate the Ronda Peridotites as well as the overlying metasediments (the Casares unit and other upper units).

Later, Navarro-Vila & Tubía (1983) and Tubía (1988) differentiated the unit of Ojén (encompassing the unit of Sierra Blanca) situated at the bottom, above the Guadaiza unit, and, over this unit, the Los Reales unit (with the Ronda Peridotites). Martín-Algarra (1987) followed this division with the peridotites situated above the Blanca unit. Balanyá and García-Dueñas (1991) joined the Ojén and Guadaiza units in the Guaro nappe, above which they situated the Bermeja unit (only the Ronda Peridotites); over this unit (over the peridotites) they placed the Jubrique unit, and at the top the Benarrabá Tectonic Imbrications (another name of the Federico-Casares units). Bessière et al. (2021) did not consider the previously cited position of the Ronda Peridotites in the Guadaiza area, considering the contact of the peridotites with the tectonic units of this sector to correspond to a large-scale extensional detachment (joining in this detachment contacts formed in two notably different times, the Carboniferous and early Miocene).

Sanz de Galdeano (2017, 2019, 2021, 2022) considered the Guaro nappe to have no real independent existence, but rather to form part of the Jubrique unit (or Los Reales unit, when the peridotites situated at its bottom are also considered).

Despite the great number of tectonic units cited, only two types of units are considered here, the Jubrique (or Los Reales) unit and the Federico-Casares units. This drastic reduction is explained in the Discussion.

The Jubrique unit: Its lower visible metasedimentary sequences are Paleozoic dark schists and quartzites (Carboniferous and probably even older), with a thickness reaching more than 2000 m at some points. Above lie phyllites of several hundred meters thick, also containing quartzites. These latter rocks date to the Triassic and perhaps also to the Permian. At a higher position appear Triassic marble formations more than 1000 m thick (not in the area of Jubrique), which have interleaved calc schists, quartzites, and other rocks.

Furthermore, igneous rocks are abundant, particularly peridotites (the Ronda Peridotites) situated under the Jubrique unit, whose meaning is described later. Their emplacement provoked the formation of a migmatitic aureole, partially corresponding to gneisses (Tubía et al., 2013), which in opinion of Ruiz-Cruz & Sanz de Galdeano (2014) occurred during the Carboniferous. But this age is debated.

Moreover, in the area of the Guadaiza River (Fig. 2 B, cross-sections 1 and 2), appear orthogneisses whose age and meaning are also discussed below. The proposed ages are early Miocene (Esteban et al. 2011) or Carboniferous-Permian (Acosta-Vigil et al., 2014; Sanz de Galdeano & Ruiz-Cruz, 2016).

The Federico-Casares units: This name, given by Didon et al. (1973), corresponds to units situated in the Rif (Federico) and in the Betics (Casares). They have also been named Imbrications of Benarrabá (Balanyá & García Dueñas, 1991) and Intermediate units (Sanz de Galdeano et al., 2001). These units have a low metamorphic grade which progressively diminishes in the higher units. They present Paleozoic and Triassic rocks.

The understanding of the structure of the Alpujarride in this sector depends on the position attributed to the Ronda Peridotites and also by the age of their emplacement. This is discussed in the next section. Here, other aspects of the structure are indicated:

A general overview of the structure of the sierras Blanca and Mijas is indicated, respectively, in the cross-sections A and B of the Fig. 3. Notably, they bear substantial reversed folds with opposed vergences, also implying the peridotites.

Clearly related to the Jubrique unit is the “subunit” of Yunquera. This corresponds to a tectonic slice situated under the Jubrique unit (Sanz de Galdeano, 2021) in the contact with the Federico-Casares units and very near the Subbetic (External Zone). This Yunquera unit has lithological sequences equivalent to the Jubrique unit.

Over the Jubrique-Los Reales unit exist the above-mentioned Federico-Casares units. These constitute slices, variable in number, depending on the different places, with imbricate structures, which in turn underlie the Malaguide Complex.

From Málaga to Vélez-Málaga, the Alpujarride Complex does not crop out because it is covered by the Malaguide Complex (Fig. 1).

Boulin (1970) studied this region and described its lithological series. Elorza (1979) studied the area of Sierra Tejeda and also described the Benamocarra tectonic unit, whose attribution to the Alpujarride or to the Malaguide complexes is debated. Avidad & García-Dueñas (1981) differentiated the two main tectonic units existing in the area of Almuñécar and Motril. Later, Alonso-Chaves & Orozco (2007) emphasized the importance of the extensional tectonic in this area.

More recent articles have been published on the area, though without consequential novelty in the differentiation of units. Also, Williams & Platt (2017) examined the Alpujarride Complex, with a special emphasis on this sector, but their tectonic interpretations are considered here to be incompatible with data directly observable in the field, as indicated above.

The higher Alpujarride tectonic unit in this sector is equivalent to the Jubrique unit and, although several names have been given, probably the main one used is Salobreña. Its lithological sequence is equivalent to that of the Jubrique unit although the peridotites are not visible, but gneisses exist, well expressed particularly in the area of Torrox, (Fig. 4), which Zeck & Whitehouse (1999) dated as Permian. Also Triassic metabasites appear, intercalated in the phyllites and in the marbles.

The middle unit is the Almijara unit (previously called the Herradura unit by Avidad & García-Dueñas, 1981). It does not present gneisses, and the dark schists are visible only locally. Light schists are abundant and the different formations of marbles are very well developed, with thicknesses at many points exceeding 1000 m.

The main structure of this sector is the thrust of the upper Salobreña unit over the middle Almijara unit (Fig. 4). Moreover, in some areas, tight folds appear with different vergences, in some cases opposite, as is the case of Sierra Tejeda (cross-section C of Fig. 3). Laterally, eastwards, the structure of folds is noticeably less tight (cross-section D of Fig. 3).

Prominent later faults have affected the original tectonic superposition of the units. This occurred for instance in the area situated from Alcaucín to Nerja (Fig. 4), where major NW-SE dextral strike-slip faults cut through the units, interpreted as a testimony of the extensional detachment of Sierra Tejeda by Alonso-Chaves & Orozco (2007).

To the west, situated over the Salobreña unit, lies the Benamocarra unit (in the area of Vélez-Málaga). This is formed by dark schists which towards the top progressively change to shales attributable to the Malaguide Complex. Elorza (1979) and other authors assigned this unit to the Alpujarride Complex owing to the presence of the aforementioned schists, considering that the Malaguide Complex lacks this type of metamorphic rock. However, given the total transition of these schists to the slates and lutites of the Malaguide Complex, it may be more accurate to consider the Benamocarra unit as belonging to this latter complex.

In the area between Nerja and Motril (Fig. 4), the Salobreña unit cuts that of the Almijara at different levels, in such a way that in some places the complete formation of marbles, and even part of the phyllites and schists of this latter unit, are tectonically laminated.

For this sector, Aldaya (1969) distinguished, from bottom to top, in addition to the lower Lújar unit, the units of Cástaras, Alcázar, Murtas, and Adra. Aldaya et al. (1979) considered these same units and also indicated a general division of the Alpujarride Complex into three main groups of units.

Jacquin (1970) studied the Sierra de Gádor, describing its stratigraphy and structure, also including the unit of Felix.

Estévez et al. (1985), studying the structure of the Alpujarride units in the SW part of Sierra Nevada, disputed the existence of the Cástaras unit (considering it to be part of the Lújar unit). Orozco et al. (2004) described the structure of the Sierra de Lújar, interpreting it as having formed in an extensional process. Martín-Rojas (2006) studied the area of the Sierra de Gádor and its western prolongation, describing the structure and the stratigraphy.

More recently, Sanz de Galdeano & López-Garrido (2014 a, b) described, respectively, the tectonic window of Albuñol (Fig. 4) (where the Gádor unit, equivalent to that of Lújar, appears), and the structure of the Sierra de Lújar.

The upper unit of this sector has no particular changes in its lithological sequences compared with the previous sectors. It corresponds to the units of Murtas and Adra, defined by Aldaya (1969), but taken together because their lithological sequences are complementary. Perhaps the most appropriate name for this unit, which encompasses the two previous units, is Adra. In this new Adra unit, dark schists to marble formations appear, but no basal gneisses.

For the middle unit, the name of Calahonda can be used, this name referring to a village situated to the east of Motril, because only this unit appears in this locality (Fig. 4). Moreover, this unit crops out in several tectonic windows, although these can be considered as forming part of a single unit. Its lithological sequences are equivalent to that of the Almijara unit.

The lower Lújar unit (or Lújar-Gádor unit) has light schists at the bottom and phyllites above, and several thick formations of marbles measuring more than 1000 meters. The marbles show only a low grade of metamorphism, being practically limestones and dolomites at many points, with observable fossils.

The limit between this sector and the western one (practically coinciding with the meridian of Motril) is of interest because it is the western border where the lower Alpujarride units crop out. At this limit, the thickness of the units concerned is not conserved. Particularly the middle Almijara unit has undergone extreme thinning, to the point that has been completely laminated in some places.

A possible explanation for this thinning can be found in the structure of the sierras of Lújar and Escalate. In Lújar an enormous northward reversed syncline appears (cross-section E, Fig. 6), and, as indicated Boulin (1966), the Escalate area, situated to the south, corresponds to the normal flank of the southern anticline. This structure was probably formed prior to and during the stage when the units were thrusting. The volume of this structure existing in the Sierra de Lújar, combined with the push of the upper Alpujarride unit caused the middle Almijara unit to thin and even become totally sheared in some places.

The same strong shearing occurs to the east, on the western border of the Sierra de Gádor (Figs. 4 and 5). This sierra also constitutes a large volume and the same phenomenon occurred in that area. This lamination is visible also in the tectonic window of Albuñol, where the Lújar-Gádor lower unit is directly covered by the Adra upper tectonic unit (cross-section F, Fig. 6), while, in between, the middle unit appears only in thin remnants.

The structure of the Sierra de Gádor is not complex, corresponding approximately to an anticline, although its southern border is thrust by the Felix unit (Fig. 5), probably a local duplication of the Lújar-Gádor unit, although Martín-Rojas (2006) proposed that it corresponds to an upper unit. Furthermore, to the SE of Alhama de Almería several slices verge northwards.

To the east of Sierra de Gádor lie the sierras Alhamilla and Cabrera, the latter reaching the coast in the area of Mojácar (Fig. 5). In both mountains, the Nevado-Filabride Complex crops out within their core, surrounded by Alpujarride lower units.

Gallegos (1975) studied the Alpujarride Complex in the SW of Sierra Nevada, and Foucault (1976) examined the area of Sierra Arana (NE de Granada). Ewert & Navarro Vila (1979) correlated the lower unit of this zone with the Lújar unit.

In this sector the lithological sequences of the three types of Alpujarride units (lower, middle and upper) correspond to those indicated above. In the upper unit, the basal gneisses are not represented, but the rest of the sequences are similar to those of the Jubrique or Salobreña unit. The middle and lower units have a great abundance of marbles. In the lower unit (the Padules unit of Sanz de Galdeano et al., 1995), the phyllites are well represented. A comparison of this lower unit with the Lújar unit shows great similarity (Ewert & Navarro-Vilá, 1979), perhaps with a lower metamorphic field aspect.

The Federico-Casares units are well exposed. The transition of their lithological characteristics from the Alpujarride to the Malaguide complexes is clear, progressively changing in metamorphic grade, lower in the unit situated in the higher position, in contact with the Malaguide Complex.

The Mora unit presents upper (perhaps also middle) Triassic rocks and Jurassic to Cenozoic sediments, but the lower levels are not visible. The Triassic rocks are composed of marbles with very low metamorphism, practically identical to those of the lower Alpujarride Padules unit. Probably, under a middle Alpujarride unit, both units, i.e. the Padules unit and that of the Mora, are stratigraphically continuous-that is, they are likely the same single unit.

The thrusting of the lower Alpujarride unit over the Nevado-Filabride Complex is clearly visible and the same is true of the corresponding thrusts of the middle and upper units, making their tectonic superposition clear. In the southwestern border of Sierra Nevada, this superposition is noticeably affected by slides caused by the Neogene uplift of Sierra Nevada (cross-sections G and H, Fig. 6).

On the northwestern edge of this sector the structure is more complex. There, in contact with the External Zone (the Subbetic), appear the Frontal units, which at the same time are situated above the Malaguide Complex (Sanz de Galdeano & López-Garrido, 2016), and this latter overlies the Federico-Casares units. In turn, these latter units thrust over the tectonic stack of the upper, middle, and lower Alpujarride units above mentioned. The cross-section I of Fig. 7 shows this structure, including also the position of the Mora unit.

While the tectonic superposition of the lower, middle, and upper Alpujarride units has a N or NW wards vergence, the Federico-Casares units have the opposite vergence, towards the S or SE. This different vergence may correspond to a later superposition, formed during the westward drift of the Internal Zone, in the early Miocene.

On the other hand, if the interpretation that the Mora unit is the same lower Alpujarride unit of this sector is correct, then this would be evidence that some Alpujarride units bear lithological sequences spanning Jurassic and Cenozoic formations.

Delgado (1978) studied this area and distinguished five tectonic Alpujarride units, which from bottom to top are: Tetica, Santa Bárbara, Quintana, Blanquizares, and Hernán Valle. The first three, Tetica, Santa Bárbara, and Quintana, can be assigned to the lower Alpujarride units, while Blanquizares would correspond to the middle Alpujarride units, and Hernán Valle would form an upper Alpujarride unit.

The Santa Bárbara unit is striking for the great thickness of the phyllites and marble formations, showing some interbedded doleritic masses. Similar, but with lesser thickness conserved, are the Tetica and Quintana units. The Blanquizares unit has similar sequences, but apparently with a slightly higher grade of metamorphism. The Hernán Valle unit presents dark schists and quartzites, phyllites, and marbles.

These units form a well-defined thrust stack: the lower unit is situated over the Nevado-Filabride Complex in well-exposed contact, including a tectonic window located to the SE of the locality of Gor. Notably, great folds are visible in the marbles, particularly in the Santa Bárbara unit.

Here, several parts can be considered, all located near the Almanzora River (Fig. 5). These parts lie directly to the north of Sierra de los Filabres, and also in the Sierra de las Estancias, and in the Sierra de Almagro. Further to the NE lies the Sierra de Enmedio.

North of Sierra de los Filabres: This sierra, situated to the east of the Sierra de Baza and south of the Almanzora River (Fig. 5), presents the same general thrust structure. Many local names have been assigned to their Alpujarride tectonic units.

Simon (1963), Vissers (1981), De Jong & Bakker (1991), Molina Cámara & Orozco (1983), among others, have worked on this sierra. Some names of these units include Almanzora, Ballabona-Cucharón, Variegato, Tetica, and Colorao.

Nonetheless, on the whole, only two different units can be distinguished, although locally some of these units are duplicated. The lower one, the Almanzora unit, has lithological sequences similar to other lower Alpujarride units, with phyllites and marbles, practically limestones, and interbedded metabasic rocks. Above lies the Variegato unit, formed by schists (comparable in aspect to Malaguide Carboniferous formations), phyllites, and marble (or limestone) formations, also including metabasic rocks.

According to its lithological sequences and tectonic position, the Almanzora unit is a lower Alpujarride tectonic unit, while the Variegato unit can be considered an upper tectonic unit, but also with some characteristics assimilable to the Federico-Casares units. This means that the middle and upper Alpujarride tectonic units are not represented with the characteristics discernible in more western sectors. That is, the Alpujarride Complex decreases in the metamorphic grade towards the east or northeast, a trend indicated by De Jong & Bakker (1991).

Sierra de las Estancias: To the north of the Almanzora river is the Sierra de las Estancias (Fig. 5). As in Sierra de los Filabres, several tectonic units are distinguishable. Vries & Zwaan (1967) and Soediono (1971) studied the lithological sequences of these units. Akkerman et al. (1980) separated, from bottom to top, the units Partaloa, Oria, and Montroy, the latter being equivalent to the Hernán Valle unit, cited above in relation to Sierra de Baza.

The Partaloa unit presents a Paleozoic sequence somewhat comparable to the Malaguide Carboniferous formations, and above lie phyllites and quartzites with gypsum followed by carbonatic formations, limestones, and dolomites. By virtue of its position, this unit can be attributed to the lower Alpujarride units. The Oria (or Blanquizares-Oria) unit presents dark schists and quartzites, phyllites, limestones, and dolomites, locally marbled. Metabasites are present in all the sequences. This unit can be considered to be a middle Alpujarride unit, although with a lower metamorphic grade. The Montroy unit has similar sequences and, according to its position, can be considered an upper Alpujarride unit, although its grade of metamorphism is clearly lower than that of the Jubrique/Salobreña unit. Finally, in the higher position, and under the Malaguide Complex, lie two Federico-Casares units, there called Peña Rubia and Tropeles (situated near Lorca) ensuring the paleogeographic passage to this last complex.

Sierra de Almagro: This sierra, situated to the SE of the Sierra de las Estancias (Fig. 5), was studied by Simon (1963, 1964), who distinguished, from bottom to top, the units of Almagro, Ballabona, Cucharón, and Variegato, with the Malaguide Complex above. Later, Egeler and Simon (1969) considered the three lower cited units as forming part of a new complex, the Ballabona-Cucharón Complex, but Bakker et al. (1989) changed this name to the Almagride Complex, restricting it to the Almagro unit.

Barragán (1993) distinguished the Almagro unit, above the Ballabona-Cucharón unit and at the top of the Variegato unit. García-Tortosa et al. (2002) considered these two first units to be really the same but corresponding to different parts of the same lithological sequences. These authors called it the Tres Pacos unit, with the Variegato unit above it, and discarded the idea of a new complex, Ballabona-Cucharón or Almagride.

The Tres Pacos unit is formed by schists, quartzites, and phyllites, together with a thick carbonatic sequence of limestones and dolomites having interbedded gypsum and pelites, also with basic rocks. For its position, directly above the Nevado-Filabride Complex, this is regarded as a lower Alpujarride unit. The Variegato unit is similar to that of the northern part of the Sierra de los Filabres. Above it lie several klippes of the Malaguide Complex.

The metamorphic grade of these units is lower than in geometrically equivalent units situated more to the west. The thrusts are the more important structures, although noticeable E-W folds can also be found (cross-section J, Fig. 7).

Sierra de Enmedio: In this small, elongated mountain (Fig. 5) appears an Alpujarride unit with its northern part covered by a Malaguide unit. Here, Fernex (1962) distinguished three units, that of the Malaguide Complex, one of the Alpujarride, and a third, corresponding to the Nevado-Filabride Complex. Egeler and Simon (1969) considered only one unit under that of the Malaguide and attributed it to their Ballabona-Cucharón Complex.

The Alpujarride unit is formed by phyllites and quartzites locally with metaconglomerates and gypsum. Above, appear limestones as well as metabasites. Its metamorphic grade is very low, much lower than in equivalent western units, surely reaching a lower temperature during its development. This may explain why Egeler and Simon (1969) differentiated the Ballabona-Cucharón or Almagride Complex in this area.

In addition, there is a local slice, which is presumably the reason why Fernex (1962) individualized another unit.

This area is complex and the attribution of several units to the Alpujarride or to the Nevado-Filabride complexes changes depending on the author. For instance, the mountain called Lomo de Bas, situated 12 km to the SW of Mazarrón (Fig. 8) and reaching the sea, has been attributed to one or another complex. Pavillon (1972) and Espinosa Godoy et al. (1974) posited that this mountain formed part of the Alpujarride Complex, while Álvarez & Aldaya (1985) and Álvarez (1987) ascribed it to the Nevado-Filabride Complex. Another unit, that of Cantal, was attributed by Álvarez & Aldaya (1985) to the Alpujarride Complex, while García-Tortosa et al. (2002) considered it to belong to the Nevado-Filabride Complex. In the present work, this latter interpretation is accepted. In this area, only two Alpujarride units are considered, although strongly affected by later faults.

The lower unit has Paleozoic schists, practically shales, that recall the equivalent Malaguide formations. Above, in both units, phyllites and quartzites as well as limestones and dolomites appear. Especially in the higher unit, conglomeratic layers are interbedded, in which pebbles and cobbles are hardly deformed.

Besides the thrusting of the units, the most outstanding feature is the tectonic arc of Águilas-Mazarrón, formed by the displacement of more than 60 km, caused by the sinistral strike-slip fault of Garrucha or Palomares. Thus, in the eastern block of this near N-S fault, the Internal Zone was pushed northwards, giving rise to the aforementioned arched shape while, at the same time, many other faults were formed in its interior. All this caused many deformations in the previous thrusting structures, provoking many difficulties in the correlating of the units.

This area is the eastern prolongation of the previous one, although its structure is simpler. Here, Espinosa Godoy et al. (1974) and Gordillo Martín et al. (1974) described two Alpujarride units and another one belonging to the Ballabona-Cucharón Complex, situated in a lower position, which they called the Intermediate unit. García-Tortosa et al. (2000) distinguished two Alpujarride units, although at some points local slices could be considered to be other units. Also, locally, certain units have intermediate characteristics with the Malaguide Complex (Federico-Casares type units), for instance to the east of Cartagena.

These units present phyllites and quartzites, in some cases practically shales of various colors and carbonates, limestones, and dolomites. The units of very low grade of metamorphism, previously attributed to the Ballabona-Cucharón or Almagride Complex, here are included in the Alpujarride Complex.

The main structural element is the tectonic superposition of the units. Also, major folds appear, in some cases very tight, with predominant northwards vergence.

Sierra Espuña and Sierra Tercia: In Sierra Espuña, Paquet (1969) described four Alpujarride units, and similar divisions of units were proposed by Kampschuur et al. (1974) as well as Egeler (1974). Martín Rojas et al. (2007) also distinguished four units situated under the Malaguide Complex, where three of them can be considered Federico-Casares type units, whereas the lower one (Molinos unit) has a lesser degree of metamorphism, although greater than that of the above-mentioned Federico-Casares units. The Molino unit is formed by phyllites and quartzites, locally with gypsum, as well as marbles. The Federico-Casares units progressively change from a scant metamorphic grade to becoming more metamorphic in the lower unit.

The main feature of this area is the tectonic superposition of the units (cross-section K, Fig. 7), later affected by approximately E-W folding.

In the small mountain of Sierra Tercia, situated in the SW prolongation of Sierra Espuña (Fig. 8) appears an Alpujarride unit similar to the Molinos unit, but also showing dark schists and quartzites, attributable to the Paleozoic. Above, lie two Federico-Casares units.

This mountain is situated near the city of Murcia. Kampschuur (1972) contended that, in this sierra, under a unit of the Malaguide Complex, lay one Federico-Casares type unit, the Pestillos unit, an Almagride unit, the Carrascoy unit, and at the bottom an Alpujarride unit. Sanz de Galdeano et al. (1997) maintained this differentiation, although attributing the Carrascoy unit to the Alpujarride Complex.

In the Carrascoy unit, dark lutites appear, perhaps belonging to the Paleozoic. Above these are phyllites and quartzites, with the top being limestones, some displaying Muschelkalk facies. The unit also contains gypsum and dolerites.

Apart from the thrusting of the units, major E-W folds appear (cross-section L, Fig. 7). In addition, there are N-S folds, probably formed by the effect of the large sinistral strike fault (Fig. 8) which cut through the W and NW border of the sierra.

The outcrops making up this area encompass the small island of Tabarca and some outcrops being situated in Callosa and Orihuela (Fig. 8). All these units were attributed by De Jong (1991) to the Almagride Complex. Martín-Rojas et al. (2007) also described them.

A common characteristic of all the units of this area is their low metamorphic grade, for which they were placed in the Ballabona-Cucharón or Almagride Complex. Their general sequence is formed by phyllites, practically shales, with different colors from bluish-gray to red and violet, locally containing gypsum and quartzites. Above, lie limestones, dolomites, and marls, in some cases with Muschelkalk facies. The total thickness of these sequences reaches several hundred meters.

The outcrops in this area are separated by Quaternary sediments and therefore at every site several tectonic units have been differentiated, each with its own name. However, probably only three different tectonic thrusting units exist.