Geomorphology of the Lozoya River Drainage Basin Area (Community of Madrid, Spanish Central System)

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Geomorphology of the Lozoya river drainage basin area (Community of Madrid, Spanish Central System)

Theodoros Karampaglidis, Alfonso Benito-Calvo & Alfredo Pérez-González

To cite this article: Theodoros Karampaglidis, Alfonso Benito-Calvo & Alfredo Pérez-González (2015) Geomorphology of the Lozoya river drainage basin area (Community of Madrid, Spanish Central System), Journal of Maps, 11:2, 342-353, DOI: 10.1080/17445647.2014.926103 To link to this article: https://doi.org/10.1080/17445647.2014.926103

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Geomorphology of the Lozoya river drainage basin area (Community of Madrid, Spanish Central System) ∗ Theodoros Karampaglidisa,b , Alfonso Benito-Calvoa and Alfredo Pe´rez-Gonza´leza aCentro Nacional de Investigacio´n sobre la Evolucio´n Humana, Paseo Sierra de Atapuerca s/n. 09002, Burgos, Spain; bDepartamento de Geodina´mica, Facultad de Ciencias Geolo´gicas, Universidad Complutense, Ciudad Universitaria s/n, 28040 Madrid, Spain (Received 18 November 2013; resubmitted 3 May 2014; accepted 15 May 2014)

The Lozoya river catchment is located in the NE part of the Spanish Central System intracratonic orogen (Community of Madrid, Spain). A detailed geomorphological map of this area was designed at 1:50,000 scale, in order to analyze surface processes and Late Cenozoic landscape evolution. The map covers 925 km2 and it was produced within a geographic information system (GIS) using several spatial datasets including a 5 m resolution digital elevation model (DEM), aerial photographs, digital anaglyphs, and lithological, topographic and historic maps. These datasets were used to form a preliminary interpretation, which was checked and completed through ﬁeld work. This geomorphological mapping has allowed us to analyze landform spatial and temporal distribution. Landforms were differentiated according to the following geomorphologic processes: structural, gravity, ﬂuvial, glacial, weathering and polygenetic. Keywords: geomorphologic map; landscape evolution; Lozoya whatershed; Spanish central system; late cenozoic; GIS

1. Introduction In this paper, we present a geomorphological map of the Lozoya river watershed (see Main Map). This was produced in order to understand the Cenozoic landscape evolution of this area situated in the E sector of the Spanish Central Range (Figure 1). In this area, the geodynamic evolution and lithostructural characteristics of the regional bedrock have produced a singular intramountain erosive staircase-plain model. In the study area several papers have dealt with a range of geomorphological topics. Various studies focused on long-term landscape evolution (Birot & Sole´ Salaris, 1954; Centeno, Pedraza, & Ortega Ruiz, 1983; Fernańdez, 1987; Garzoń, 1980; Pedraza, 1978; Penk, 1972; Schwenzer, 1937), glacial features (Centeno et al., 1983; Palacios, De Marcos, & Vasquez-Selem, 2011; Pedraza and Carrasco, 2006), the local karstic systems (Karampaglidis, Benito-Calvo, Pe´rez-Gon- za´lez, Baquedano, & Arsuaga, 2011; Pe´rez-Gonza´lez et al., 2010; Torres et al., 1995, 2005), and the regional morphostructure (Arenas Martıń, Fu´ster, Martıńez, Del Olmo, & Villaseca, 1991; Bellido et al., 1991; De Vicente et al., 2007). In contrast, we integrate the identified landforms

∗Corresponding author. Email: [email protected]

# 2014 Theodoros Karampaglidis Journal of Maps 343

Figure 1. (A) Location of the study area situated in the Central Iberian Peninsula (Spain). (B) Lozoya river and the main tributaries of NE Tajo Basin. (C) 3D view of the DEM. and produce a detailed synthetic geomorphologic map. This allows us to deﬁne the Cenozoic geomorphological sequence characterized mainly by an ancient stepped system of Paleogene and Neogene planation surfaces and a Quaternary erosive downcutting model. The Neogene levels were associated with piedmonts deposits and sedimentary units located in the Duero and Tajo Cenozoic basins, while the Quaternary rock terrace sequence of the Lozoya river correlated with the strath terrace sequence of the Jarama river (Cenocoic basin, Karampaglidis et al., 2011; Pe´rez-Gonza´lez & Gallardo, 1987), the main collector of the Lozoya river.

2. Geological context and setting The Lozoya river drainage basin covers 925 km2, with the highest elevation Pen˜alara peak (2428 m a.s.l.), in the Sierra Guadarrama, and the lowest elevation in the adjoining area of the 344 T. Karampaglidis et al.

Lozoya and Jarama rivers (700 m a.s.l.). The current climatic conditions vary from a humid climate at higher altitudes to semi-arid conditions in depressions (Pe´rez-Gonza´lez et al., 2010). This area presents high lithological heterogeneity (Arenas Martıń et al., 1991; Azor et al., 1991; Bellido et al., 1991), which determines to a significant degree the formation of the principal surface morphological features. The Proterozoic and Paleozoic metamorphic rocks (Precambrian, Cambrian, Ordovicic, Silurian and Devonic) located to the NE and NW part of the watershed are characterized by low permeability, low erodibility (where fluvial incision trends to form canyons and V-shaped valleys), and rock weathering processes. Additionally, the Permian plutonic rocks (granites and adamelites) are strongly affected by high weathering, however Permian dykes situated in the SE sector show low erodibility and weathering. In the SE and NE part of this sector a Cretaceous sedimentary sequence was identified (Arenas Martıń et al., 1991; Bellido et al., 1991). The lowest part is composed of fluvial sediments, the ‘Facies Utrillas’ (clays, gravels, lutites, carbonates and sandstones). The top of the sequence is represented by marine transgression sediments consisting of sands, lutites, carbonates, sandstones and dolomites. At the end of the Cretaceous sequence, lacustrine deposits and gypsums have accumulated. This sequence is characterized by high weathering (karstic dissolution) and high erodibility; lying on them in angular-progressive disconformity, are Cenozoic continental deposits with high erodibility (Figure 2). These sediments correspond to Paleocene (conglomerates with calcareous boulders) (Figure 2(A)) and Neogene fluvial fans (Figure 2(A) and 2(B)). Pleistocene fluvial deposits and karstic infills are also located in the area. These sediments are composed of boulders, gravels, sands, silts and clays (Arsuaga, Baquedano, & Pe´rez-Gonza´lez, 2006; Karampaglidis et al., 2011; Pe´rez-Gonza´lez et al., 2010). Similarly, during the Late Pleistocene, glacier deposits (moraines) formed in upland areas of the Sierra de Guadarrama (Centeno et al., 1983; Palacios et al., 2011; Palacios, Andre´s, De Marcos, & Vasquez-Selem, 2012; Pedraza & Carrasco, 2006). Lastly, colluviums, peat formations and solifluidal deposits were developed during the Late Pleistocene and Holocene (Bellido et al., 1991; Karampaglidis et al., 2011). This area presents a complex tectonic evolution. Corresponding to the Variscan Orogeny, Bellido et al. (1991) and Arenas Martıń et al. (1991) recognized five phases of deformation defined by penetrative schistosity and folds. Later, a period of stretching processes and exten- sional tectonism was identified, being characterized by a fracture network of E-W direction and the emplacement of hypabyssal rocks (Arenas Martıń et al., 1991; Bellido et al., 1991). Capote & Fernandez Casals (1975; Capote, Gonza´lez Casado, and De Vicente, 1987; Capote, De Vicente, & Gonza´lez Casado, 1990) differentiated the existence of three deformation stages during the Alpine period: first during the Oligocene-Lower Miocene (thrusting associated with the principal morphostructural formations of the Iberian Chain), second during the Miocene (NE-SW structures and folding of the Mesozoic and Cenozoic deposits), and the third occurring during the Upper Miocene-Pliocene limit to the present day, defined by several impulses recognized in a distinct sector of the Spanish Central Range (Arenas Martıń et al., 1991; Aznar Agui- lera, Pe´rez-Gonza´lez, & Portero Garcıá, 1995; Bellido et al., 1991; De Bruijne, 2001). More recently, De Vicente et al. (2007) recognized two primarily deformation stages developed during the Oligocene-Lower Miocene (NW-SE and NNW-SSE shortening) and the Upper Miocene-Pliocene (uniaxial extension to strike-slip with NW-SE shortening direction), together with some contemporary seismic activity, showing the last same kinematic characteristics.

3. Methods This study was carried out after detailed geomorphological mapping and terrain analysis within a geographic information system (GIS). To produce our map we utilized 1:5000 topographic maps, 1:50,000 historic topographic maps corresponding to the years 1917, 1927 and 1937 (National Journal of Maps 345

Figure 2. (A) Paleocene continental conglomerates with red silts and clays. (B) Miocene Paleosoils with ﬂuvial fan deposits (boulder, cobbles and gravels). (C) Miocene ﬂuvial fan deposits (boulder, cobbles and gravels).

Geographic Institute, IGN), 1:33,000 aerial photos (Geographical Military Institute, SGE), 1:50,000 geologic maps (Spanish Geological Survey, IGME), orthophotos from the National Plan for Aerial Orthophotography (PNOA), and fieldwork. The topographics maps were used to generate a 5 m resolution digital elevation model (DEM). These data were combined with orthophoto images for creating digital anaglyphs. The anaglyphs and aerial photographs were used for 3D visual identification of landforms. The digitization of the landforms was performed using 1:5000 topographic maps and the lithological background pro- vided by the geological maps, detailed geomorphological mapping and field work. Historical maps were georeferenced and digitized in order to reconstruct the actual river base level and 346 T. Karampaglidis et al. identify landforms currently flooded by the Lozoya reservoirs. The geomorphological map legend was designed following the guide created by the Spanish Geological Survey (Martin Serrano et al., 2004). The DEM was also used to calculate slope, drainage network and Stream Length-Gradient index (SL). SL index is widely used as a profile xy to identify anomalies in stream profiles (Hack, 1973). In this work, we created an SL map using the 5 m resolution DEM, following the method proposed by Font, Amorese, and Lagarde (2010).

4. Geomorphological features The main geomorphological features identiﬁed in the study can be classiﬁed according to their morphogenesis.

4.1. Structural landforms The main morphostructure of the Lozoya basin have been deﬁned by the Variscan and Alpine Orogeny cycles. General directions of the NE-SW pop-up and pop-down megastructures were delimited during the Variscan and Alpine tectonic activity (Figure 3). Also, N-S Paleozoic syn- clines and anticlines are identiﬁed in the East part of the study area, in the Ayllon Mountains.

Figure 3. Panoramic views and main morphologies located in the (A) South Piedmont connecting with the Madrid Cenozoic basin, (B) Atazar reservoir area, (C) Lozoyuela village area. Legend: (1) Cuestas, (2) Miocene continental deposits, (3) planation surfaces, (4) Neogene erosive surfaces, (5) Strath terraces, (6) Rock terraces, (7) Internal tectonic depressions limits, (8) River incisions, (9) Altitudes. Journal of Maps 347

Other signiﬁcant structural landforms that have been mapped are the schistosity marks in the Paleozoic metamorphic rocks and the bedding plane marks (NE-SW) in the Cretaceous and Paleo- gene sedimentary rocks. Finally, cuestas and hog backs following NE-SW directions have been recognized in the contact area among the spanish Central Range and the Madrid basin and in the Pinilla del Valle sector (Figure 3(A) and 4(C)).

4.2. Gravitational l These types of landforms have been identiﬁed in the foothills and were formed by bedrock weathering and slope processes. We classify two main types of landforms: colluviums and colluvials. Col- luvium deposits have been formed by severe gravitational processes, whereas colluvial deposits have been formed through a mix of slope gravity processes and water action (Figure 5(C) and 5(D)).

4.3. Fluvial landforms An intramountain fluvial downcutting model was developed during the Quaternary period forming a fluvial sequence containing up to 24 terraces. These levels are composed mainly of rock-terraces (Karampaglidis et al., 2011), distributed in the Lower Pleistocene (from TD15: +62-64 m to TD2: +190-195 m), the Middle Pleistocene (from TD20: +17-20 m to TD16: +50-55 m), the Upper Pleistocene (TD22: +6-8 m, TD21: +11-14 m) and the Holocene (TD24: +1-2 m, TD23: +3-5 m) (Figure 3(A), 3(B), 4(A) and 4(B)). This complex record suggests that the Lozoya watershed was particularly sensitive to climate changes and uplift move- ments during the Quaternary. The upper valley, (Pinilla del Valle sector), follows a NE-SW (pop down) tectonic depression, where the Lozoya river presents a complex fluvial style. From Rasca- frıá village until Pinilla del Valle village, the Lozoya river forms a shallow gravel-braided facies model which transforms to a wandering gravel-bed facies model between the Pinilla del Valle and Lozoya villages. In this area, the river system is characterized by high sediment loading of clastic rocks with polygenic composition (Figure 6). This sector is one of the few areas where Quaternary

Figure 4. Panoramic views of the principal ﬂuvial geomorphological features of the (A) Lozoya river on black slates after the Atazar reservoir, (B) Canyon of the Lozoya river downstrem from the Atazar Reservoir, (C) Hog backs (Late Cretaceous Limestones) and crests (Paleozoic granites) in the contact zone between the Madrid Cenozoic basin and the Spanish Central Range, (D) Glacial cirque in the Pen˜alara peak (2.428 m a.s.l.). 348 T. Karampaglidis et al.

Figure 5. A and (B) Late Pleistocene cave infilling sediments in the Pinilla del Valle archaeo-paleontolo- gical site. (C) Pleistocene colluvial sediments (NE of the Lozoya village area). (D) Colluvium deposits (Lozoya village area). E) Late Pleistocene fluvial torrential sediments (Rascafrıá village area).

fluvial deposits are located (strath terraces, alluvial fans and fluvial deposit infillings in the local karstic system) (Figure 5(A), 5(B), 5(E) and 6), although old small rock terraces are also identified, corresponding to the Early-Middle Pleistocene (Karampaglidis et al., 2011). Downstream, in the Buitrago de Lozoya area, the Lozoya river can be classified as an incised meander bedrock river (2.71 sinousity) cut from T18 (+30-35 m), showing a WNW-ESE general direction. The best preserved morphologies In this sector are erosive rock terraces. Late-Middle Pleistocene levels are also well preserved. In the Atazar area, the morphology of the Lozoya river is controlled by fractures of E-W and N-S direction, showing the valley general direction (NNW-SSE). In this sector, rocky terraces are located on the Paleozoic rocks and on the Neogene deposits. The highest Neogene surface appears +220 m above the present river channel and possibly corresponds to the last Neogene aggradation level. The lower sector (Cerro de la Oliva) is characterized by the highest Lozoya river incision and sinuosity (3.36), forming canyons which are developed from T5 (+160-165 m) and where fluvial processes such us rotation, extension and abandoned mean- ders have been mapped (Figure 4(A)). In this area, the rocky terraces are located on Palaeozoic Journal of Maps 349

Figure 6. (A) Upper Lozoya fluvial floor valley deposits. (B) Lozoya fluvial floor valley deposits located in the Lozoya tectonic depression area. (C) and (D) Strath terrace downstream from the Atazar reservoir. black shales and Neogene deposits. A karstic system was also formed in Cretaceous Limestones, where fluvial deposits are preserved up to 840 (m a.s.l.) (Pontoń de la Oliva Cave, Torres et al., 1995, 2005). Finally, in this area, a well preserved terrace sequence of the Jarama river is found and correlates with the Lozoya river terrace sequence (Karampaglidis et al., 2011; Pe´rez-Gonza´lez & Gallardo, 1987).

4.4. Glacier and periglacial, landforms In the upland areas of the Guadarrama range mountain, between altitudes of 1600–2400 m a.s.l., erosive and depositional glacier landforms are identified (Figure 4(D)). These forms are poorly preserved, corresponding to a degraded glacier cirque with morainic deposits (Centeno et al., 1983; Palacios et al., 2011, 2012; Pedraza & Carrasco, 2006). The majority of the periglacial landforms are seasonal and difficult to map. In this map, we only include nivation niches and blanket bog deposits as periglaciar landforms (Arenas Martıń et al., 1991; Bellido et al., 1991; Pedraza, Gilsanz, Centeno, Acaso, & Rubio, 1987).

4.5. Lacustrine and endorheic landforms Soft depression areas with backwaters, hydromorphic processes and organic soils are identiﬁed in the Lozoya basin. Small glacier lakes were mapped in the Pen˜alara glacier cirque. 350 T. Karampaglidis et al.

Figure 7. (A and B) Weathering forms on Late Cretaceous Limestones. (C, D, E and F) Weathering forms on Paleozoic granites.

4.6. Weathering landforms Weathering forms have been located in Cretaceous carbonate rocks. In the study area, karstic systems are identified and associated with the Lozoya river. The karstic landforms are depressions, passages, collapses and sinkholes, which can be covered or infilled by alluvial, colluvial and debris deposits (Reguerillo Cave and Pinilla del Valle Cave), containing a rich Pleistocene archeo-paleon- tological record (Pe´rez-Gonza´lez et al., 2010; Torres et al., 2005)(Figure 5(A), 5(B), 7(A) and 7(B)). Furthermore, in the Cabrera Range, weathering processes are identified on Granitic Permic rocks (domes, tors, crests, granite weathering sand, weathering of joint blocks, corestones, weather pans, rock falls, granitic boulders, pedestral rocks and tafonis) (Figure 7(C–F)).

4.7. Polygenetic forms The oldest classified surfaces correspond to pre-Quaternary degraded and reworked planation surfaces (Birot & Sole´ Salaris, 1954; Fernańdez, 1987; Garzoń, 1980; Pedraza, 1978). The earliest surfaces are the peak planation surfaces. They are poorly preserved and lack of correlated sediments makes the sequence difficult to classify. The proposed model for the origin of these surfaces Journal of Maps 351 involve an original Pre-Alpine peneplain, which was deformed during the Alpine deformation cycle (Fernańdez, 1987; Garzoń, 1980; Pedraza, 1978, 1994). In lower positions, we have identified four younger erosion surfaces. These levels were developed between the Oligocene-Lower Miocene and the Pliocene (levels SE1 to SE4, Benito-Calvo & Pe´rez-Gonza´lez, 2010), and cor- relate with piedmont deposits and sedimentary units of the Cenozoic basins. This class of landforms is located as deformed and degraded polygenetic erosive surfaces, remodeled pediments and polygenetic residual forms.

5. Conclusions Within a GIS we used spatial datasets to produce a detailed geomorphological map at 1:50,000 scale, which contains information about Cenozoic landscape evolution of the Lozoya river drainage basin. This sector of the Eastern part of the Spanish Central Range is characterized by a complex geomorphological evolution. The oldest landforms correspond to planation surfaces. The earliest phases of the Alpine tectonic cycle probably was affected the Pre-Alpine peneplain surface, gen- erating a surface staircase model. At lower geomorphological positions four degraded planation Neogene surfaces were identified. These surfaces have been associated with piedmont deposits and the endorheic continental infilling of the Cenozoic sedimentary basins. Below the Neogene surfaces, during the Quaternary, an intramountain rock terrace sequence model composed of 24 levels was recognized, generated by fluvial downcutting. Meanwhile, during the Upper Pleis- tocene cold periods glacial and periglacieal landforms developed, restricted to the summits areas. Finally, river incision on diverse bedrock lithologies, and a variety of structural characteristics, caused significant variation in weathering and landform development.

Software Esri ArcGIS 10.2 was used to manage and analyze the spatial data. Erdas Imagine 2011 was used to create digital anaglyph models. The ﬁnal layout of the geomorphological map was produced using Corel Draw X3.

Acknowledgements This work was supported by the research Project of the archaeological sites of the Pinilla del Valle (Spain), ﬁnanced by Community of Madrid (Spain), Ministry of Culture (Spain), Mahou Group and Canal Isabel II (Spain).

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