Hidden Images in Atxurra Cave (Northern Spain) a New Proposal for Visibility Analyses of Palaeolithic Rock Art in Subterranean

Quaternary International 566-567 (2020) 163–170

Contents lists available at ScienceDirect

Quaternary International

journal homepage: www.elsevier.com/locate/quaint

Hidden images in Atxurra Cave (Northern Spain): A new proposal for visibility analyses of Palaeolithic rock art in subterranean environments T

Iñaki Intxaurbea,d, Olivia Riverob,Ma Ángeles Medina-Alcaidec, Martín Arriolabengoad, Joseba Ríos-Garaizare, Sergio Salazarb, Juan Francisco Ruiz-Lópezf, Paula Ortega-Martínezg, ∗ Diego Garatea, a Instituto Internacional de Investigaciones Prehistóricas de Cantabria (IIIPC, Gobierno de Cantabria, Universidad de Cantabria, Santander). Ediﬁcio Interfacultativo, Avda. Los Castros s/n, 39005, Santander, Spain b Dpto. Prehistoria, Historia Antigua y Arqueología, Universidad de Salamanca, 37008, Salamanca, Spain c Dpto. Historia, Facultad de Letras, Universidad de Córdoba, 14071, Córdoba, Spain d Dpto. Mineralogía y Petrología. Euskal Herriko Unibertsitatea/Universidad del País Vasco, 48940, Leioa, Spain e Archaeology Program, Centro Nacional de Investigación sobre la Evolución Humana (CENIEH), Paseo Sierra de Atapuerca 3, 09002, Burgos, Spain f Dpto. de Historia. Universidad de Castilla – La Mancha, 16001, Cuenca, Spain g Independent Researcher

ARTICLE INFO ABSTRACT

Keywords: Visibility has been the subject of study in Palaeolithic rock art research ever since the discovery of Altamira Cave Cave art in 1879. Nevertheless, until now, the different approaches have been based on subjective assessments, due to Viewshed computational limitations for a more objective methodology. Nowadays, cutting-edge technologies such as GIS Archaeological context allow us to address spatial studies in caves and overcome their geomorphologically complex and closed char- Cave geomorphology acteristics. Here we describe an innovative methodology that uses computing tools available to any researcher to GIS study the viewsheds of the graphic units in decorated caves. We have tested its validity on the recently dis- Palaeolithic covered rock art ensemble of Atxurra Cave, in Northern Spain. We demonstrate that this technology (GIS), widely used in other fields of archaeology, especially in outdoor studies, is also useable in caverns, taking into account the complex morphologies -ceilings and diverse floor-levels, for example. These programmes have also allowed us to consider the lighting systems used by the prehistoric groups inside the cave, as well as various data previously estimated by other authors, such as the height of individuals during the European LUP. The dynamism of these tools −2.5D-, as well as the advancement of new 3D GIS technologies, will allow in the future remarkable progress in these types of structural studies for a better understanding of Palaeolithic cave art phenomena.

1. Introduction: research precedents and objectives by other researchers (Pastoors and Weniger, 2011). The final aim of these studies is usually to observe patterns in the The visibility (and invisibility or concealment) of Palaeolithic rock topographic distribution or organization of the rock art ensembles art images in European caves has attracted several researchers’ atten- within the cave. These patterns can then be compared between different tion since the discovery of cave art in Altamira in 1879 (Sanz de rock art sites (generally within the same geographical and chron- Sautuola, 1880), and its subsequent approval by the scientific com- ological framework). This has led to numerous interesting proposals, munity in 1902 (Cartailhac, 1902). In recent years, this aspect has been from the use of the term of sanctuaries for these caves (Leroi-Gourhan, considered by several authors, usually to compare decorated zones in 1964) to inferences about their organization (González-Sainz, 2017)or the same cave, or to illustrate Point Of Views (POVs) of each figure or even attempts to interpret their meaning in the form of sentences panel on the cave plan (González-García, 2001; Villeneuve, 2008; (Sanchidrián, 1992). Interest in spatial studies is more than justified, Garate, 2010; Ruiz-Redondo, 2014; Ochoa and García-Diez, 2018; and for that reason methods should be developed that are as objective Jouteau et al., 2019). They measure the visibility area in some cases, as possible, to validate the observations and avoid (as far as possible) all and compare it with such other spatial features as occupancy, estimated subjective interference or errors derived from personal appreciations.

∗ Corresponding author. E-mail address: [email protected] (D. Garate). https://doi.org/10.1016/j.quaint.2020.04.027 Received 13 February 2020; Received in revised form 3 April 2020; Accepted 15 April 2020 Available online 21 April 2020 1040-6182/ © 2020 Elsevier Ltd and INQUA. All rights reserved. I. Intxaurbe, et al. Quaternary International 566-567 (2020) 163–170

Most spatial studies involve estimating the visibility area on a cave recording method previously tested (Trimmis, 2018). plan. The use of GIS is usually avoided, adducing the limitations pro- Prior to the geolocation process, and to minimize as much as pos- duced by the three-dimensional features of caves, identified previously sible any type of magnetic distortion that could alter the measurements, in a work in La Griega Cave (Ortega, 2014), and other reasons of costs the device was calibrated within the karst system itself, and in parti- or time consumption. cular, in the main gallery of Armiña Cave (the lower part of the cave- The use of GIS in “sensorial” archaeology, and specifically in visi- system) (Fig. 2A). bility studies in rock art (Wheatley and Gillings, 2000; Gillings, 2015; Geolocating the archaeological elements with DistoX2 requires a Díaz-Andreu et al., 2017; Wernke et al., 2017; Wienhold and Robinson, process similar to the production of a conventional speleological 2017) has become very popular in recent years because of their preci- survey, in which it is necessary to draw a polygonal starting from a sion and ability to interpret the terrain, despite their strengths and point 0. To position this point 0 in space with coordinates in a specific limitations, previously identified (Gillings, 2017). These techniques are datum, it can be georeferenced on the surface, using a differential GPS, usually employed in open-air studies, but some precedents are known in for example. However, if a previously georeferenced point-cloud exists, closed and three-dimensionally complex sites (Landeschi, 2019), in- as is the case of the caves that have been scanned three-dimensionally cluding caves (Ortega, 2012, 2014). One of most successful analytical -and our case of Atxurra-, obtaining the coordinates of identifiable platforms directly uses the 3D mesh for different analyses of visibility in “reference points” (Fig. 2B and C) is easy, and the polygonal can be these types of environments (Dell’Unto et al., 2016; Landeschi et al., started from there. 2016). Once the fieldwork was carried out (Fig. 2D), the data was pro- The general objective of the present paper is the implementation of cessed in the VisualTopo® (David, 2009) program, making the pertinent “digital technologies” (like GIS or 3D models) to advance in studies on magnetic declination corrections. Finally, the data was converted to the the spatial structure of Upper Palaeolithic rock art ensembles in cave datum of our choice (ETRS 89 UTM 30). environments. As noted above, 3D GIS tools, like Lines of Sight (LOS), have been tested for visibility analyses in complex environments 3. Methodology: analysing visibility using GIS inside the cave (Landeschi et al., 2016, 2019; Landeschi, 2019). However, despite the accurate results that could be obtained in simulations and archae- 3.1. Recreation of cave geomorphology ological analyses with these 3D GIS technologies, rapid conversions to 2.5D GIS technology can offer also valid results, for example for Atxurra Cave was scanned by the company Gim-Geomatics SL using a viewshed analyses of Palaeolithic rock art ensembles in caves. The terrestrial Laser Scanner 3D Faro® Photon 120. Approximately 59.6 specific objectives of the present study are: 1) to describe the steps million points have been obtained per scan, in 538 scan stations. As for followed using certain GIS programmes to obtain precise measurements the accuracy of the operation, the estimated error is 1 mm per 25 m, of the viewshed areas of parietal figures, identifying and resolving the with 90% reflectance. After this, the point cloud was treated with main limitations; 2) to test their validity in the cave of Atxurra ArcGIS® by Gim-Geomatics SL to obtain two raster files. This work was (Northern Spain) and verify the results in situ, since its conditions are done in “strict” 3D because in 2.5D it fails both on walls and when ideal for this purpose (decorated sectors hidden from the main transit passages overlap. First a raster was defined with a cell size of about zones in the passage, archaeological remains associated with parietal 2.5 cm on which we dump the data that interests us. In this case art and related to the illumination systems used by the artists, etc.); 3) “minimum Z” is defined as the minimum value of the 3D mesh in that to explain different kinds of visibility of images in the same cave re- cell (if there are several nodes, only the minimum dimension) and garding their location, but also in relation with their iconography and “maximum Z” the maximum value. That is, search among all the nodes technique or the different illumination systems. that fall in the cell, for example 5 × 5 cm2, (square defined by xmin, ymin, xmax, ymax) and choose the highest and lowest, to obtain two 2. Materials: the Palaeolithic rock art ensemble of Atxurra Cave raster archives, representing the position of floor level (GroundDEM) and ceilings (CeilingsDEM). However, it is important to note that the The cave of Atxurra is formed in Aptian-Albian reef limestone procedure to import 3D files in GIS had already been defined (Opitz and (Lower Cretaceous) in the province of Biscay (Northern Spain) Nowlin, 2012). (Fig. 1A). Although this prehistoric site has been known since 1929 In our case, the coordinates of 3D models (in at least 6 digits) was (Barandiarán, 1961), in 2015 a parietal art complex was discovered previously reduced to 3/4 digits, because of the size of files. The lim- deep in the cave, with more than 100 engraved and painted animal itations of GIS software mean that editing 3D (ESRI, 2012) is im- figures in Upper Magdalenian style based on techno-stylistic conven- possible, so the coordinates could only be reconverted (creating a 2.5D tions (Garate et al., 2016, 2020). GIS), once the rasters to be used had been extracted. The panels with rock art are between 186 m and 366 m from the Prior research had been carried out on karst geomorphology and prehistoric entrance, in the upper level of the system, and they are lo- cave evolution in Atxurra (Arriolabengoa et al., 2018, submitted). It cated mainly above side-ledges reached by more or less dangerous proved that no great changes have taken place in the areas with rock art climbs (Fig. 1B). Exhaustive exploration and identification fieldwork since the Upper Palaeolithic. Some detrital and lithochemical sedi- has been carried out between 2016 and 2020, and 257 Graphic Units mentation has occurred -mainly in the lower part of the gallery-, but in (GUs) have been documented. terms of visibility, the current state resembles the original perceptions, In addition, an enormous amount of Inner Archaeological Context which have not been altered by geomorphological evolution. (IAC) remains have been documented near the rock art panels (usually under them). These types of vestiges provide valuable information 3.2. Processing GIS data about the “use-life” of the cave during the past (Clottes, 1993; Medina- Alcaide et al., 2018). Most attention was paid to remains stemming To perform visibility analysis in Atxurra, we obtained each GU's from the illumination systems, which provide useable data to make viewshed using the “Viewshed 2” analysis tool in ArcGIS®’s ArcMap™ inferences about the kind of illumination used (Medina-Alcaide et al., (Fig. 3). To solve the main problems of these analyses (Gillings, 2017), 2015, 2019). we have calculated the maximum angle to observe these points, even Once all forms of evidences in the cave (GUs and also IAC elements) 360° horizontal and 0-90° vertically. With this, we can calculate the had been documented, they were georeferenced using a DistoX2 device, maximum area within which each GU is visible, according to positive in conjunction with a tablet using an Android system with Bluetooth, indivisibility between the observer and the rock art: i.e., “if the GU can and with TopoDroid® (Corvi, 2015) application installed, following a see me, I can see the GU”.

164 I. Intxaurbe, et al. Quaternary International 566-567 (2020) 163–170

Fig. 1. Location of analysed rock art ensemble. A: Position of Atxurra Cave in the Iberian Peninsula (source: https://www.juntadeandalucia.es/ institutodeestadisticaycartograﬁa/DERA/). B: 3D model of Atxurra Cave, made by GIM-GEOMATICS, detailing the location of decorated sectors.

Fig. 2. Geolocation process using DistoX2. A: Calibration of DistoX2, in Armiña Cave. B: position of point 0 on a remarkable speleothem. C: Obtaining the coordinates of this last point in the point cloud, using SCENE LT© of FARO©. D: Geolocation of archaeological elements in the cave (IAC elements or GUs).

First of all, we have performed a prior step to consider the situation when the altitudes are higher than the panel minimum Z. This way, we of ceilings, because our scenario -a subterranean gallery decorated with will create a new raster with zero values when the ceilings allow visi- rock art-is three-dimensionally complex and enclosed. It consists of bility, and high values when the altitudes or the forms of ceilings block identifying the minimum value in altitude (minimum Z value) of each it. Later, we sum this raster with the GroundDEM (the raster containing panel, reclassifying CeilingsDEM (the raster containing the Z values of the Z values of ﬂoors) using the “Plus” tool, creating a modiﬁed new ceilings) with the “Reclassify” tool, and after that weighting with raster to perform the viewshed analyses of GUs located in this particular “Weighted Overlay” tool. We assign high values (e.g. 9 value) when the panel. altitudes of the ceilings are lower than our panel minimum Z (i.e. the The “Viewshed 2” tool, unlike other similar tools, does not have a Z ceilings can block the visibility), and we assign a “restricted” value factor parameter, so, to ensure the accuracy of the output visibility

165 I. Intxaurbe, et al. Quaternary International 566-567 (2020) 163–170

Fig. 3. A conceptual map created using Model Builder in ArcGIS®, showing the steps of the method followed to measure the area of the viewshed of a certain GU (Atr.F’.I.01). raster, we must introduce the Z value of each GU. The tool also allows Redondo, 2018), including rock art studies (e.g. Acevedo et al., 2019), the introduction of other variables, and these will be used. Nonetheless, these techniques remain unpopular in approaches focused on Palaeo- the results must be checked in the cave, modifying introduced variables lithic cave art -both in Europe and other zones worldwide-, although if necessary. some references are known (Ortega, 2014). In the case of Atxurra, as explained above, the enormous amount of Some of the main limitations that have hindered the use of these IAC elements found under rock art panels have allowed us to determine tools in caves are the complexity and enclosed three-dimensional nature prehistoric illumination systems (Garate et al., 2020). In particular, of underground environments. However, even if they are designed to be three different illumination techniques have been identified in Atxurra: used in the open air, current GIS technology allows some processes to torches (estimated by scattered charcoal remains found in most sec- be applied to solve these problems (Fig. 5). tors), hearths (found in Sector J) and a portable sandstone lamp (found The first limitation that we have identified is due to the ceilings: in Sector D). Particularly, the primary position of Sector J hearths, deep caves are enclosed environments, so, besides the floors, irregular in the cave and under rock art motifs, indicates their function for morphologies arising from the passage wall and ceiling (e.g. roof pen- lighting. With different multi-analytical approaches and experimenta- dants, notches, speleothem formations, etc.) can affect the visibility tion, we have estimated each illumination technique's maximum radius (Fig. 5A). These (ceilings) can be taken into account following the first of action (Medina-Alcaide, 2020), and these have been considered to steps of the proposed method, i.e., the modification of the floor raster introduce these numerical values in our analysis. Although we have based on the ceilings raster, modified using the minimal Z of the ana- avoided introducing more variables in the analyses (e.g. reflectance, lysed panel (Fig. 3). luminance, etc.), these are possible additions to make in the future. We The second main problem is also related to the three-dimensionality have also introduced mean stature during the Late Upper Palaeolithic complexity of caves. There can be two (or more) floor-levels or ob- (Holt, 2003) to simulate as closely as possible the scenario in which the stacles affecting visibility, in addition to the ceilings. In these cases, it is rock art of ensemble of Atxurra was created -and preferably observed-, possible to create different floor or ceiling rasters (for example, one for in the Upper Magdalenian. This stature −1.60 m-has only been taken as each level or obstacle), and perform the analysis using the appropriate a reference to perform our test, and it must be regarded as provisional, archive for each GU. since the anthropological record in these chronologies is limited and it Another problem is due to the limited surface of the passages, and only takes into account adults -when we know that children or people of the “Viewshed 2” function programming. The tool does not take into small stature also entered caves (Bégouën et al., 2009)- and in an up- account the “NON DATA” cells, so if there are two passages near to each right position (when they could be sitting, lying down, etc.). In any other in the same Z, the software can count the two passages as visible case, we believe that this reference serves to establish valid criteria although that may be impossible (because there is a wall between these when estimating potential viewsheds, as proven by the recent com- two zones). This can be solved by sectoring the cave into different parisons with ancient DNA (Cox et al., 2019). This value must be added rasters (one for each passage, for example). The problem can also be to establish the viewshed from a potential observer's eye height. solved by a bug that software tends to do, “increasing” exponentially Otherwise, if we do not add this value, the viewshed is considerably less the cell value when it is in a position where null values coincide with than the real one. those of ceilings or floors. This only happens in the outermost pixels, so Finally, once all the viewsheds had been obtained -one for each GU with the level of accuracy that we are working with (25 cm2), a GU is of the cave- (Fig. 4), we have measured the area (in square metres) of unlikely to be located in the outermost cell. each obtained raster. This has allowed us to make comparisons with Finally, some authors have claimed that GIS are hardly applicable to precise values (Supplementary Data. S1). a large number of sites because of their complexity, or because of the time and funding required to create certain useable archives (e.g. 4. Results and discussion Ochoa, 2017). We believe that both problems can be avoided by employing cutting edge technologies like photogrammetry, which has 4.1. Spatial analysis in cave contexts been increasingly used in rock art studies in recent years (e.g. Azéma et al., 2010; Feruglio et al., 2013; Robert et al., 2016; Rivero et al., ™ ® Despite the proven utility of GIS in sensorial archaeology studies, like 2019). With certain software (e.g. Photoscan of Agisoft ), it is possible ff visibility (Llobera, 2003; García-Moreno, 2013; Ortega and Ruiz- to create meshes, geolocate them and extract di erent rasters that can

166 I. Intxaurbe, et al. Quaternary International 566-567 (2020) 163–170

Fig. 4. Viewsheds of all GUs in Atxurra Cave, obtained using ArcMap™ in ArcGIS®. be used in GIS for these types of approaches. has been measured precisely (Supplementary Data, S1). This has allowed us to compare them with the location of each GU inside the cave, their pictorial technique, or the illumination system employed. 4.2. Implications and inferences of the analysis applied to the rock art First of all, it is necessary to note the diﬀerential preservation state ensemble in Atxurra Cave of the motifs. In general, it is possible to distinguish the engravings today, especially when they are made with diﬀerent technical The area of the viewshed of each of the 257 motifs in Atxurra Cave

Fig. 5. Main limitations of the use of GIS in caves to study rock art. A: simpliﬁed illustration of the problematic locations of rock art to perform analysis (M. Arriolabengoa, I. Intxaurbe). B: proposal of solutions.

167 I. Intxaurbe, et al. Quaternary International 566-567 (2020) 163–170 procedures and when the panel is covered by a thin reddish clay layer. figures and give prominence to others, related to the function of rock However, other walls are very badly preserved, partially erased by art (Bahn, 2011; Fritz et al., 2016; Rivero, 2016). visitors rubbing against them, or covered with thin layers of spe- We must stress that the results of our analysis are closely linked to leothem. In other cases, especially with black paintings or with some the prehistoric illumination systems employed, and their estimated fine engravings, it is very difficult to estimate their original state, due to radius of influence. It would be interesting to study the matter more their poor preservation, caused in some cases by constant water drips closely, combining different lighting methods, and introducing new and air currents. In any case, it is logical to think that when the de- variables, such as reflectance. Experimentation and the quantitative pictions were drawn, the white of the engraved lines would be more measurement of light emission in terms of radius of action and intensity visible (Delluc and Delluc, 2009), and we must take this into account can provide essential data for visibility analysis (Medina-Alcaide, before making inferences. It would be interesting to consider also pre- 2020). The dynamism of GIS allows these tests to be performed. We vious experiments about visibility (Opitz, 2017). This also underscores must also point out that in the case of large figures, multiple points the importance of the use of objective methods when making an ob- should be counted in each figure (improved software allows at least 32 jective calculation. points per GU); if not, the result would be imprecise. Once these assessments are made, we can deduce a strong correla- The results should also be compared with accessibility to the de- tion between the location of a certain GU inside the cavern, and its corated sectors. For example, the large panels in Sector J are very viewshed. This appreciation has been confirmed by the analysis with visible, but they are located deep inside the cave on a ledge 4 m high GIS. The location of art in hidden zones (e.g. small side chambers, or only reached by climbing. The study of this interaction between ac- small tubes on high ledges) generates viewsheds smaller than 7 m2. This cessibility and visibility is a key to understand the cultural appropria- is the case of sectors A, F′ or J’ Suelo, for example. It is interesting to tion of caves by Upper Palaeolithic human groups. observe that the figures located in those places are usually unfinished, and small in size. 5. Conclusions In other cases, the motifs are located in lower parts of the passage, or in transit zones, so they are more visible, with viewsheds usually In this study, we have first used GIS for a visibility analysis of larger than 10 m2. For example, this is the case of Sectors C Suelo, D′, Palaeolithic rock art inside a cave, considering all morphologies, in- G′,orG′ Suelo and I’ Suelo (Fig. 4). Here, the animal figures display a cluding the height of ceilings. The use of this method in a recently greater degree of detail, and their size increases in some cases con- discovered cave with Palaeolithic rock art (Atxurra in Northern Spain) siderably. has allowed us to test its validity. It has also demonstrated that there The case of Sector J is of special interest. It contains the cave's was a clear intention, when placing the figures in certain spaces, to give biggest panel, with 86 GUs. Its emplacement is also particular, sus- prominence to some of them (like some of those in Sector J), while pended at a height of 4 m above the transit zone in the passage other discreet sectors were chosen to “hide” figures, which were often (Fig. 6A.). Here visibility is also affected by the different types of illu- left unfinished and are smaller in size. mination considered in our analysis, but even though they are not all in The application of “digital technologies” like GIS in caves has been the same state of conservation, the visibility of the motifs is con- commonly overlooked because of its limitations and costs in time and siderably better than in other zones of the cave, particularly the GUs funding. However, we have argued here that it is possible to perform located on a roof pendant, above the panel (Atr.J.II.33-50), with a this type of analysis in these morphologically complex sites too. The viewshed larger than 30 m2. However, it is important to add that the data for the software tools has been collected by a scanned point cloud, small size of these GUs would impede their correct perception over long but it is possible to obtain the data with other methods, such as pho- distances. togrammetry. 51 animal figures can be seen in the panel and the subject matter The application of the maximum radius of influence of prehistoric seems to correlate with the degree of intent to make the figures visible. illumination systems to perform the analysis, estimated by archae- For example, of the 19 ibexes in the panel, 13 have viewsheds larger ological evidence and experimental results, as well as estimations of than the average visibility in the panel (68.4%). The same is true of mean stature in the LUP, has enabled an accurate visibility analysis. The horses (3) and bison (10), but with slightly lesser “visual prominence”, previous geomorphological study of the cave has also been funda- (66.67% and 60% respectively). On the other hand, the visibility of the mental, to discard changes in the subterranean landscape posterior to hinds (3) and the indeterminate figures (13) in the panel is always less the prehistoric visits. than the average of the general viewshed of the panel. This is because Precise and quantitative explanation of different levels of visibility they were located in lower areas of the panel. This is to say, the spatial of the rock art in the same or different panels, and comparison with organization of these different themes is also related to the visibility of their location in the cave, with their iconography and pictorial tech- each side of the panel. nique, or the illumination systems used, can be improved by employing The most visible figures include those produced with a combination the cutting-edge technologies that have been applied in other areas of of techniques (painting and engraving) and these are usually arranged archaeology. The opportunities they offer overcome the limitations that independently in central and high areas of the panel. The figures that may exist and it is expected that, as 3D GIS technologies are developed, overlap each other (for example, Figures ATR.J.II.13-18 and new approaches will take the place of subjective appreciations and ATR.J.II.52-64) are located in lower areas (in height) and have a manual measurements. smaller viewshed than the panel average. This would denote a clear The study of visibility is important to address the structure and intention of the artists to choose where to place the figures: that is, the organization of rock art ensembles and their public/private function. figures to be emphasised are located in high areas while less relevant Here we have an objective tool for a better understanding of the cul- ones are more “hidden” and they display overlapping. tural appropriation of the underground landscape by Upper Palaeolithic In Sector J, it is also remarkable that the most visible GUs are em- human groups. placed inside the radius of illumination of the four hearths. This feature, compared with the different types of techniques employed in some Funding figures (different types of engravings, combined with black painting), their size in some cases (bigger than others) and their position (on high This research was carried out within the four-year multidisciplinary parts of the walls) (Fig. 6B) denotes an intentionality to highlight these study project (2016-2020) “Study of rock art in Atxurra cave” directed GUs over the others. However, the reason for this different treatment is by Dr Diego Garate and funded by the Cultural Heritage Service of the still unknown. There may have been cultural reasons to hide some Diputación Foral de Bizkaia. I. Intxaurbe's PhD research is funded by a

168 I. Intxaurbe, et al. Quaternary International 566-567 (2020) 163–170

Fig. 6. Viewshed analysis on the Ledge of the Horses (Sector J). A: 3D restitution of the two panels (Atr.J.I & II) combined with the 3D model of the cave, showing that the panel is located over a cornice (O. Rivero, J.F. Ruiz-López, D. Garate, I. Intxaurbe, S. Salazar). B: Viewsheds of the GUs in Sector J using ArcMap™ in ArcGIS®. The most visible figures are in a high panel. The influence of the archaeological context (in these cases the presence of hearths) is also important to make inferences (M. Medina-Alcaide, J. Rios-Garaizar, M. Arriolabengoa, I. Intxaurbe, D. Garate). grant for the training of research personnel (PIF, 2019) at the Vicente Bayarri and Jesus Herrera from Gim-Geomatics, SL, for the 3D University of the Basque Country (UPV/EHU). model of Atxurra Cave and the vectorial and raster files to be processed with GIS, as well as for the comments to improve the work. Declaration of competing interest Appendix A. Supplementary data The authors declare that they have no known competing financial Supplementary data to this article can be found online at https:// interests or personal relationships that could have appeared to influ- doi.org/10.1016/j.quaint.2020.04.027. ence the work reported in this paper. References Acknowledgements Acevedo, A., Fiore, D., Ferrari, A.A., 2019. Rock art landscapes. A systematic study of The authors wish to thank the Cultural Heritage Service of the images, topographies and visibility in south-central Patagonia (Argentina). J. Diputación Foral de Bizkaia for funding the four-year multidisciplinary Anthropol. Archaeol. 56, 101101. “ ” Arriolabengoa, M., Intxaurbe, I., Bilbao, P., Aranburu, A., Ríos-Garaizar, J., Medina- study project (2016-2020) Study of rock art in Atxurra cave directed Alcaide, M.A., Rivero, O., Líbano, I., Garate, D., 2018. Geomorfología de la cueva de by Dr Diego Garate. The present study has been carried out within the Atxurra/Armiña (Berriatua, Bizkaia). In: García, C., Gómez-Pujol, L., Morán-Tejada, framework of this project. This work is part of the research project E., y Batalla, R.J. (Eds.), Geomorfología del Antropoceno. Efectos del Cambio Global “ sobre los procesos geomorfológicos: Universitat de les Illes Balears. Sociedad Before art: social investment in symbolic expressions during the Upper Española de Geomorfología, Palma, pp. 95–98. Palaeolithic (B-Art)” VP27 funded by the University of Cantabria (Spain), Arriolabengoa, M., Intxaurbe, I., Bilbao, P., Aranburu, A., Ríos-Garaizar, J., Medina- PI: Diego Garate and “Learning and development of artistic abilities in Alcaide, M.A., Rivero, O., Hai Cheng, Beyong, Líbano, I., Garate, D., (submitted). Anatomically Modern Humans; a multidisciplinary approach (ApArt)" Geomorphology for paleocaving: landscape evolution and palaeoenvironmental changes in Atxurra-Armiña cave (northern Iberian Peninsula). J. Quat. Sci. HAR2017-87739-P funded by the Ministry of Science, Innovation and Azéma, M., Gély, B., Prudhomme, F., 2010. Relevé 3D de gravures fines paléolithiques Universities (Spain), PI: Olivia Rivero. We would also like to thank to dans l’abri du Colombier (gorges de l'Ardèche). In Situ. Revue des patrimoines (13),

169 I. Intxaurbe, et al. Quaternary International 566-567 (2020) 163–170

1–15. Landeschi, G., Apel, J., Lundström, V., Storå, J., Lindgren, S., Dell'Unto, N., 2019. Re- Bahn, P.G., 2011. Religion and Ritual in the Upper Palaeolithic. The Oxford Handbook of enacting the sequence: combined digital methods to study a prehistoric cave. the Archaeology of Ritual and Religion. pp. 344–357. Archaeol. Anthropol. Sci. 11 (6), 2805–2819. Barandiarán, J.M., 1961. Excavaciones arqueológicas en Vizcaya: silibranka, Atxurra, Llobera, M., 2003. Extending GIS-based visual analysis: the concept of visualscapes. Int. J. Goikolau. Vizcaya 17, 199–219. Geogr. Inf. Sci. 17 (1), 25–48. Bégouën, R., Fritz, C., Tosello, G., Clottes, J., Pastoors, A., Faist, F., 2009. Le sanctuaire Leroi-Gourhan, A., 1964. Préhistoire de l'art Occidental. L. Mazenod, Paris. secret des bisons : Il y a 14 000 ans, l'art et la vie des magdaléniens dans la caverne du Medina-Alcaide, M.Á., Sanchidrián, J.L., Zapata, L., 2015. Lighting the dark: wood Tuc d'Audoubert. Somogy éditions d'art. charcoal analysis from Cueva de Nerja (Málaga, Spain) as a tool to explore the Cartailhac, E., 1902. Les cavernes ornées de dessins. La grotte d. Altamira, Espagne. Mea context of Palaeolithic rock art. Comptes Rendus Palevol 14 (5), 411–422. culpa d’un sceptique. L’Anthropologie 13, 348–354. Medina-Alcaide, M.A., Garate, D., Ruiz-Redondo, A., Sanchidrián, J.L., 2018. Beyond art: Clottes, J., 1993. Contexte archéologique interne. In: L’art pariétal Paléolithique. the internal archaeological context in Paleolithic decorated caves. J. Anthropol. Techniques et méthodes d’étude. CTHS, Paris, pp. 49–58. Archaeol. 49, 114. Corvi, M., 2015. Cave surveying with TopoDroid. In: 1a Convención Internacional Medina-Alcaide, M.A., Cabalín, L.M., Laserna, J., Sanchidrián, J.L., Torres, A.J., Espeleología, Barcelona, pp. 59–62. Intxaurbe, I., Cosano, S., Romero, A., 2019. Multianalytical and multiproxy approach Cox, S.L., Ruff, C.B., Maier, R.M., Mathieson, I., 2019. Genetic contributions to variation to the characterization of a Paleolithic lamp. An example in Nerja cave (Southern in human stature in prehistoric Europe. Proc. Natl. Acad. Sci. Unit. States Am. 116 Iberian Peninsula). J. Archaeol. Sci.: Rep 28. https://doi.org/10.1016/j.jasrep.2019. (43), 21484–21492. 102021. David, E., 2009. Visual topo. https://vtopo.Free.fr , Accessed date: January 2020. Medina-Alcaide, M.A., 2020. Lighting the Darkness of the Caves with Paleolithic Art: an Delluc, B., Delluc, G., 2009. Eye and Vision in Paleolithic Art. An Enquiring Mind. Studies Integral and Interdisciplinary Vision of the Internal Archaeological Context and the in Honor of Alexander Marshack. Oxbow Books, Oxford/Oakville, pp. 77–98. Wood Charcoals. Euskal Herriko Unibertsitatea/Universidad del País Vasco. Tesis Dell'Unto, N., Landeschi, G., Touati, A.M.L., Dellepiane, M., Callieri, M., Ferdani, D., Doctoral. Vitoria-Gasteiz. 2016. Experiencing ancient buildings from a 3D GIS perspective: a case drawn from Ochoa, B., 2017. Espacio gráfico, visibilidad y tránsito cavernario: el uso de las cavidades the Swedish Pompeii Project. J. Archaeol. Method Theor 23 (1), 73–94. con arte paleolítico en la Región Cantábrica. Graphic space, visibility and cave Díaz-Andreu, M., Atiénzar, G.G., Benito, C.G., Mattioli, T., 2017. Do you hear what I see? transit: the use of caves with Palaeolithic cave art in the Cantabrian region. British Analyzing visibility and audibility in the rock art landscape of the alicante mountains Archaeological Reports, 2785. BAR Publishing, Oxford. of Spain. J. Anthropol. Res. 73 (2), 181–213. Ochoa, B., García-Diez, M., 2018. The use of cave art through graphic space, visibility and ESRI, 2012. The Multipatch geometry type—an ESRI white paper. December 2008. cave transit: a new methodology. J. Anthropol. Archaeol. 49, 129–145. Resource document. [Accessed 05.02.2020]. http://www.esri.com/library/ Opitz, R., Nowlin, J., 2012. Photogrammetric modeling þ GIS. Better methods for working whitepapers/pdfs/multipatch-geometry-type.pdf. with mesh data. ArcUser. [accessed 05.02.20]. http://www.esri.com/news/ Feruglio, V., Dutailly, B., Ballade, M., Bourdier, C., Ferrier, C., Konik, S., Lacannette-Puyo, arcuser/0312/files/archaeology-inventory.pdf. D., Mora, P., Vergnieux, R., Jaubert, J., 2013. Un outil de relevés 3D partagé en ligne: Opitz, R., 2017. An experiment in using visual attention metrics to think about experience premières applications pour l’art et la taphonomie des parois ornées de la grotte de and design choices in past places. J. Archaeol. Method Theor 24 (4), 1203–1226. Cussac (ArTaPOC/programme LaScArBx). In: Vergnieux, R., Delevoie, C. (Eds.), Ortega, P., 2012. Ensayo metodológico de las aplicaciones de visibi-lidad que los SIG Virtual Retrospect, Actes de colloque de Pessac, 27-29 novembre 2013, pp. 49–54. aportan al estudio del arte paleolítico. In: Actas das IV Jornadas de Jovens em Fritz, C., Tosello, G., Conkey, M.W., 2016. Reflections on the identities and roles of the Investigação Arqueológica, JIA 2011. Universidade do Algarve. Promontoria artists in European Palaeolithic societies. J. Archaeol. Method Theor 23 (4), Monográfica, vol. 16. pp. 67–73 (1). 1307–1332. Ortega, P., 2014. Visibility: a new outlook to the study of Palaeolithic art. Preliminary Garate, D., 2010. Las ciervas punteadas en las cuevas del Paleolítico. Una expresión research. In: García, A., García, J., Maximiano y, A.M., Ríos-Garaizar, J. (Eds.), pictórica propia de la cornisa cantábrica. Sociedad de Ciencias Aranzadi, Donostia- Debating Spatial Archaeology: Proceedings of the International Workshop on San Sebastián. Landscape and Spatial Analysis in Archaeology (Santander, June 8-9th, 2012). Garate, D., Rivero, O., Ríos-Garaizar, J., Intxaurbe, I., 2016. Atxurra cave: a major new Publicaciones IIIPC, Santander, pp. 259–266. Magdalenian sanctuary in the Basque Country. Int Newslett Rock Art 76, 1–4. Ortega, P., Ruiz-Redondo, A., 2018. An approach for understanding site location pre- Garate, D., Rivero, O., Ríos-Garaizar, J., Arriolabengoa, M., Medina-Alcaide, M.Á., Ruiz- ferences on Pas River Basin during Late Magdalenian. Landscape analysis of Las López, J.F., Intxaurbe, I., Salazar, S., Libano, I., 2020. The cave of Atxurra: a new Monedas cave. J. Archaeol. Sci.: Rep 19, 804–810. major Magdalenian rock art sanctuary in Northern Spain. J. Archaeol. Sci.: Rep 29. Pastoors, A., Weniger, G.C., 2011. Cave art in context: methods for the analysis of the https://doi.org/10.1016/j.jasrep.2019.102120. spatial organization of cave sites. J. Archaeol. Res. 19 (4), 377–400. García-Moreno, A., 2013. GIS-based methodology for Palaeolithic site location pre- Rivero, O., 2016. Master and apprentice: evidence for learning in Palaeolithic portable ferences analysis. A case study from Late Palaeolithic Cantabria (Northern Iberian art. J. Archaeol. Sci. 75, 89–100. Peninsula). J. Archaeol. Sci. 40 (1), 217–226. Rivero, O., Ruiz-López, J.F., Intxaurbe, I., Salazar, S., Garate, D., 2019. On the limits of 3D Gillings, M., 2015. Mapping invisibility: GIS approaches to the analysis of hiding and capture: a new method to approach the photogrammetric recording of palaeolithic seclusion. J. Archaeol. Sci. 62, 1–14. thin incised engravings in Atxurra Cave (northern Spain). Digit. Appl. Archaeol. Cult. Gillings, M., 2017. Mapping liminality: critical frameworks for the GIS-based modelling of Herit. 14. https://doi.org/10.1016/j.daach.2019.e00106. visibility. J. Archaeol. Sci. 84, 121–128. Robert, E., Petrognani, S., Lesvignes, E., 2016. Applications of digital photography in the González García, R., 2001. Art et space dans les grottes paléolithiques cantabriques. study of Paleolithic cave art. J. Archaeol. Sci.: Rep 10, 847–858. Jérôme Millon, Grenoble. Ruiz Redondo, A., 2014. Entre el Cantábrico y los Pirineos: el conjunto de Altxerri en el González-Sainz, C., 2017. Sobre la organización de las decoraciones parietales contexto de la actividad gráfica magdaleniense. Universidad de Cantabria. Tesis paleolíticas. Impresiones a partir de Santimamiñe, Armintxe y otros conjuntos ru- doctoral, Santander. pestres de Bizkaia. In: Garate, D., Unzueta, M. (Eds.), Redescubriendo el arte parietal Sanchidrián, J.L., 1992. Códigos gráficos en algunos santuarios solutrenses de Andalucía. paleolítico. Últimas novedades sobre los métodos y las técnicas de investigación Zephyrus XLIV-XLV, 497–510. (Bilbao 2016), Kobie (serie Anejos) 16. Diputación Foral de Bizkaia, Bilbao, pp. Sanz de Sautuola, M., 1880. Breves apuntes sobre algunos objetos prehistóricos de la 135–147. provincia de Santander. Telesforo Martínez, Santander. Holt, B.M., 2003. Mobility in upper palaeolithic and mesolithic Europe: evidence from the Trimmis, K.P., 2018. Paperless mapping and cave archaeology: a review on the applica- lower limb. Am. J. Phys. Anthropol.: Off. Publ. Am. Assoc. Phys. Anthropol. 122 (3), tion of DistoX survey method in archaeological cave sites. J. Archaeol. Sci.: Rep 18, 200–215. 399–407. Jouteau, A., Feruglio, V., Bourdier, C., Camus, H., Ferrier, C., Santos, F., Jaubert, J., 2019. Villeneuve, S.N., 2008. Looking at Caves from the Bottom-Up: a Visual and Contextual Choosing rock art locations: geological parameters and social behaviours. The ex- Analysis. Master’s Thesis. University of Victoria, Victoria. ample of Cussac Cave (Dordogne, France). J. Archaeol. Sci. 105, 81–96. Wernke, S.A., Kohut, L.E., Traslaviña, A., 2017. A GIS of affordances: movement and Landeschi, G., Dell'Unto, N., Lundqvist, K., Ferdani, D., Campanaro, D.M., Touati, A.M.L., visibility at a planned colonial town in highland Peru. J. Archaeol. Sci. 84, 22–39. 2016. 3D-GIS as a platform for visual analysis: investigating a Pompeian house. J. Wheatley, D., Gillings, M., 2000. Vision, perception and GIS: developing enriched ap- Archaeol. Sci. 65, 103–113. proaches to the study of archaeological visibility. NATO ASI Life Sci. 321, 1–27. Landeschi, G., 2019. Rethinking GIS, three-dimensionality and space perception in ar- Wienhold, M., Robinson, D.W., 2017. GIS in rock art studies. In: The Oxford Handbook of chaeology. World Archaeol. 51 (1), 17–32. the Archaeology and Anthropology of Rock Art. Oxford University Press.

170