Journal of Archaeological Science 123 (2020) 105241 Available online 2 October 2020 0305-4403/© 2020 Elsevier Ltd. All rights reserved. Comparing depositional modes of cave sediments using magnetic anisotropy J.M. Par´ es a, * , I. Campa˜ na a , M. Duval b, a , M.J. Sier a, c , A.I. Ortega d, a , G.I. L´ opez a , J. Rosell e, f a Geochronology & Geology Program, CENIEH, Paseo Sierra de Atapuerca 3, 09002, Burgos, Spain b Australian Research Centre for Human Evolution, Griffth University, Australia c Department of Earth Sciences, Oxford University, South Parks Road, OX1 3AN, Oxford, United Kingdom d Fundaci´ on Atapuerca, Carretera de Logro˜ no, 44, 09198, Ibeas de Juarros, Spain e Institut Catal` a de Paleoecologia Humana i Evoluci´ o Social, c/ Marcelí Domingo s/n, Campus Sescelades, 43007, Tarragona, Spain f ` Area de Prehistoria, Dept. d’Hist` oria de l’Art, Univ. Rovira i Virgili, Fac. de Lletres, Av. Catalunya, 35, 43002, Tarragona, Spain A R T I C L E INFO Keywords: Cave sediments Fabric analysis Quaternary Karst Preferred grain orientation Archaeology ABSTRACT Deciphering the origin and depositional history of archaeological and paleontological deposits is fundamental to evaluate artifact and fossil contextualization. We present new rock magnetic data based on the anisotropy of magnetic susceptibility (AMS) that allow the fabric analysis and characterization of depositional modes in cave sediments. This approach was tested on both fossiliferous and sterile deposits for Gran Dolina and Galeria lo- calities from the Atapuerca karstic complex (Spain). Our AMS approach has allowed to determine paleoenvir- onmental conditions in both sites, as well as to establish where a given sedimentary unit preserves primary depositional fabrics or has possible post-depositional perturbation. In this sense, it is worth emphasizing that even the sampled horizons that have hominid remains Gran Dolina show no signs of fabric disruption or evidence for massive transport of the sedimentary particles. 1. Introduction Karstic caves have the potential of preserving excellent sedimentary records for the Quaternary and therefore a comprehensive understand- ing of the depositional environment is paramount. Very often they contain sedimentary records rich in fossils and therefore the origin of the lithostratigraphic units is critical to properly interpret the fossiliferous record. Establishing the origin and depositional history of such deposits is fundamental in order to evaluate fossil contextualization, and gener- ally to understand archaeological sites (e.g., Karkanas and Goldberg, 2019). Multilevel caves are typically produced by progressive river downcutting, a process that is also refected by staircases of strath river terraces in the surrounding valleys. Cave passages, when they are at or just below the water table, are subjected to frequent fooding and consequent deposition of slackwater sediments and channel deposits by stream fows are quite common. Such events are identifed as either mesoscopic layers of food sediments (e.g., White, 2007) or as thin pa- tina in speleothems (Feinberg et al., 2020). As the local water table lowers through time, due to progressive river incision, cave passages are gradually abandoned and eventually intersected by the slope of the topographic surface due to stream incision, ceiling collapse, or fssuring, all leading to the formation of cave entrances. At the cave entrance and typically up to several meters into the cave, processes such as scree, slope wash, and sliding bed deposits will produce a variety of gravel accumulation, diamictons, and channel facies, depending on water availability and particle size (e.g., Bosch and White, 2004). Since the study of Kukla and Lozek (1958) all these amalgam of terrigenous, clastic deposits in caves have been categorized in two broad groups, namely “entrance facies” and “interior facies” deposits. The term entrance facies typically refers to sediments transported from the cave surroundings or cave walls by gravity, water or en masse (slope, wash deposits, debris fow). For example, when an opening intersects the slope of a valley, a talus cone will form at the cave entrance by super- fcial material that simply slides by gravity or by mass transport. These deposits are typically poorly-sorted, frequently loosely packed (e.g., Ford and Williams, 2007; Osborne, 1998), and mostly consist of lime- stone debris (in the case of karstic caves) and mud. On the contrary, the so-called interior facies deposits are found in parts that are more remote and far from the cave entrance, in total darkness, and typically in the vadose and upper phreatic zone of the cave system. Deposition modes in * Corresponding author. E-mail address: josep.pares@cenieh.es (J.M. Par´ es). Contents lists available at ScienceDirect Journal of Archaeological Science journal homepage: http://www.elsevier.com/locate/jas https://doi.org/10.1016/j.jas.2020.105241 Received 3 June 2020; Received in revised form 3 September 2020; Accepted 3 September 2020