Сегодня мы обладаем ограниченными данными (иногда они полностью отсутствует) для выяснения контекстовых и постседиментных процессов, а также о том, каким образом формировалась пещера. Данное исследование, основанное на тафономии крупных млекопитающих, позволило нам выделить два источника происхождения этих форм животных. Причиной многочисленных останков пещерных медведей является их спячка, и в ряде случаев их туши были разделаны in situ. Другие останки фауны, относящиеся главным образом к травоядным, были привнесены гоминидами, но разделка туш происходила не у задней стены пещеры, где были обнаружены кости. Никаких следов проживания человека не было найдено в тыльной части стоянки; люди, возможно, находились у входа в пещеру главным образом в летнее время. Гигантский пещерный медведь (Ursus spelaeus) проживал в пещере в зимне-весенний период, занимая ее тыльную часть.

После того как отложения достигли потолка пещеры, летучие мыши заняли пространство в ее задней части, ранее принадлежащее медведям и время от времени посещаемое человеком. Новые формы минералов в окаменелостях и седиментах указывают на сезонные изменения во влажности и температуре внутри пещеры в эпоху плейстоцена. Но гуано и просачивание едкой жидкости вызвало сильное разъедание останков после их погребения, и некоторые из них сегодня невозможно восстановить. Особенно вредным было воздействие гуано на коллаген. И наконец, в эпоху голоцена поверхность седиментной последовательности подверглась эрозии за счет высокой энергии водных потоков, которые вымыли верхние слои седиментов и снова открыли пещеру людям и животным.

Keywords Large mammal taphonomy Lesser Caucasus Bat guano Fossilization Ursus spelaeus Pleistocene Fossil humans

Introduction

Fossils are direct witnesses of past life forms that have reached the present through fossilization. Fossil sites cannot be considered as a snapshot of the past (Shipman 1981); on the contrary, they provide a record of the biotic and abiotic sequences of events extending over space and time and may not be an original image of the past (Fernández-López 1991). Ivan A. Efremov observed that species recovered from fossil sites were often not part of living associations but were brought together in specific locations, forming fossil accumulations due to thanatocoenoses (death associations) in alien

surroundings. Efremov (1940) observed that this situation was especially prevalent in terrestrial environments and had special relevance to paleoecological interpretations. Efremov (1940, 1950) proposed a new discipline to investigate the transition of past biological entities from the biosphere to the lithosphere in order to ensure paleoecological interpretations and other paleontological reconstructions were as accurate as possible. Efremov named this new discipline Taphonomy.

Taphonomy provides information on past contemporaneous organisms (with ethological implications), and their associations with past environments, climates and ecosystems. Taphonomy may also inform us about fossilization environments, and provide evidence of possible mixtures of more modern fossils combined with older fossils by reworking of sediments. In summary, taphonomy is an integrative and multidisciplinary investigation that aims to reconstitute the past in all details. It is often the case that scarcity or poor preservation of fossils may limit paleontological studies, but from a taphonomic viewpoint, even poor preservation provides much information.

Taphonomy investigates fossils for information gained from past processes, both biotic, for example modifications left by saprophagous fungi or bacteria, root-marks made by plants, butchery marks or cooking by humans, tooth marks and digestion traces by carnivores, and abiotic, for example weathering and breakage. These processes may act before or after burial. Taphonomy also investigates the traces recorded on fossils and on the sediment in which they are preserved, for example fossilized burrows or nests of underground animals and plants, or traces left by unknown predators on the bones of their prey (Fernández-López 2000). These traces provide information about the activity of past contemporaneous organisms that interacted with the sediment or animal carcasses and give evidence of their behavior, living strategies and paleoecology (Andrews et al. 2016). All this informs us about conditions during decay, the types of environment to which remains were exposed, diagenetic processes and modifications forced by seasonal/climatic changes. In summary, all processes that give rise to fossils provide information about past organisms and allow us to gain information about their paleobiology, way of living and evolutionary traits (Fernández López 1981, 1991, 1995, 2006).

Taphonomic Agents

Taphonomic modifications occur at death or soon after (Weigelt 1927). The earliest stage of surface modification that can be recognized is predation, as indicated by skeletal representation, breakage and digestion, as well as by superficial modifications. Taphonomic effects of predation have been extensively studied by various authors (Behrensmeyer and Hill

1981; Brain 1981; Bunn 1983; Haynes 1983; Andrews 1990; Pobiner 2008; Egeland et al. 2008; Martin 2008), and some aspects relate to human and carnivore competition (e.g., Blumenschine and Selvaggio 1988; Selvaggio 1994, 1998; Blumenschine 1995; Capaldo 1995, 1997, 1998; Domínguez-Rodrigo 1997, 1999; Selvaggio and Wilder 2001; Domínguez-Rodrigo and Barba 2006). Signs of carnivore action are seen as tooth marks, bone breakage, digestion and, in the case of humans, cut marks. Differences between predation and scavenging are shown by which anatomical elements show signs of carnivore activity, as there is a sequence of access that may distinguish between primary (usually predators) or secondary (usually scavengers) access to dead animals. Sometimes, the distinction between primary and secondary access by carnivores (humans included) is complex and predation versus scavenging may not be distinguished.

Whether predation is involved or not, decay of carcasses results in the loss of soft tissues (Weigelt 1927). Environmental conditions (e.g.,: humidity, temperature, fluid percolation, acidity/alkalinity) have a strong influence on the decay sequence by biotic agents, as well as secondary mineral growth and corrosion (Fernández-Jalvo et al. 2010a). Microorganisms (Nabaglo 1973; Korth 1979) or insect action (Dodson 1973; Behrensmeyer 1978; Kitching 1980; Smith 1986; Britt et al. 2005, 2008; Fernández-Jalvo and Marin-Monfort 2008; Hutchet et al. 2011) are ubiquitous processes, and the sequence of activity has important forensic value when soft tissues are still present. The action of these organisms can also have physical effects on the bone hard tissues (Wedl 1864; Hackett 1981; Bell 1990; Bell et al. 1996) as well as chemical (see Smith et al. 2016). Forensic studies (Bell et al. 1996) suggest that when carcasses are not affected by predation or scavenging, the body’s own indigenous bacterial gut flora are responsible for decay and may affect the bone through the vascular network.

Bone remains lying on the surface of the ground, may be exposed to weathering, trampling and abrasion by wind or water. Weathering on bones is identified as cracks, fissures and exfoliation of the surface of the remains (Behrensmeyer 1978). Weathering comprises all effects on bone by subaerial agents due to changes in temperature, humidity and sun exposure (Behrensmeyer 1978), with different effects in tropical savannah (Behrensmeyer 1978), temperate (Andrews and Cook 1985; Andrews 1990), desert (Andrews and Whybrow 2005) or tropical forest habitats (Tappen 1994). Depending on the habitat and, therefore, and on the intensity of environmental or weathering agents, the time span of bone modifications varies.

Trampling produces scratches on the bone surface, breakage, bone dispersal and abrasion (Andrews and Cook 1985; Behrensmeyer et al. 1986; Fiorillo 1989; Andrews 1990; Lyman 1994; Blasco et al. 2008). Distinction between striations by trampling and cut marks has been a controversial

subject, as they strongly mimic each other (Andrews and Cook 1985; Behrensmeyer et al. 1986; Olsen and Shipman 1988; Domínguez-Rodrigo et al. 2009). Rounding affects broken edges as well as anatomical protuberances and it may be the result of trampling, abrasion by water or wind, and digestion (Behrensmeyer 1975; Korth 1979; Boaz 1982; Shipman and Rose 1983, 1988; Denys et al. 1995, 2007; Fernández-Jalvo and Andrews 2003; Thompson et al. 2011). The effects of these processes is seen as macroand micro-scopic alteration on fossil bone and bone surface texture modifications that distinguish each process (Fernán- dez-Jalvo and Andrews 2003; Fernández-Jalvo et al. 2010a).

After burial, bones are protected from the worst effects of surface weathering and trampling, but they are still in a biologically active environment. The pH of soils where bones are initially buried has been shown to be an important taphonomic agent (Gordon and Buikstra 1981). Some soils produce strong chemical corrosion, even destruction of bones, both by extreme acidity or alkalinity. Bone corrosion by acidic soils in wet and sheltered conditions in open air environments has been observed by Andrews (1995), who noted that corrosion affected articular eminences in such a way as to mimic carnivore activity that is classified as ‘hollowing out’ or ‘scooping out’ (Sutcliffe 1970; Haynes 1980, 1983; Binford 1981). The main difference between bone corrosion and carnivore action is that salient angles in contact with the soil are the only parts affected by corrosion, while carnivores may alter any surface and leave tooth marks on the bone surface (Fernández-Jalvo et al. 2010a). Acid soils produce etching of tooth enamel, and in extreme cases of bone as well. High alkalinity produces superficial desquamatory or exfoliation of surface bone (Fernández-Jalvo et al. 1998, 2002), similar in appearance to late stages of weathering, but differing from it by the fact that weathered bones are cracked and split before exfoliation (Behrensmeyer 1978; Andrews 1990). Root marks may form on the surfaces of bone, and may cause corrosion in association with fungi or bacteria. Fungal and bacterial activity in the soil continues to break down the bone tissue. All these agents produce distinct and localized modifications that may affect any area of the surface.

During the stages reported above, some molecular changes occur in the original bone (bone diagenesis). Preservation/destruction of bone histology, organic (collagen, DNA) or mineral (bioapatite and stable isotopes) components of bone are related to the environment both before and after burial (Tütken and Vennemann 2011). Structural changes of bone tissues contribute to understanding modifications by biotic and abiotic agents (such as microorganisms, hydrolysis, pH, humidity, temperature, or fluid percolations) that may influence changes in organic and mineral bone bioapatite composition. Bone changes in organic composition related to weathering have been observed by Trueman et al. (2004). These authors