Characterisation of post-depositional taphonomic processes in th accumulation of mammals in a pitfall cave deposit from southeastern Australia Andrew M. Kos 1 Institute of Geology, Swiss Federal Institute of Technology ETH, Zurich 8093, Switzerland Received 12 July 2001; received in revised form 21 June 2002 Abstract McEachern’s Deathtrap Cave (G49/50) is a classic pitfall trap located in southeastern Australia, which has been collecting terrestrialanimalssince the Late Quaternary. Dispersaland breakage offossil bone elements are recognised as dominant taphonomic processes. The sedimentary sequence contained within the cave consists of an upper and lower sequence, where two distinct types of bone modification are identified. The degree of bone breakage gradually increases with depth and is attri sediment compression and trampling. Minor in situ breakage has occurred as a result of rock-fall and/or trampling. Bone d processes are indicated by a deficit in element representation required to account for whole skeletons based on MNI calcu Bone elements that are easily transportable by flowing water have a low frequency of representation in the sedimentary s In the cave floor bone lag deposit, shallow, intermittent flowing water is suggested by the dominance of transverse limb o and the low frequency of stable orientations that only occur in the most sensitive flow indicators, e.g. pelves. 2003 Elsevier Science Ltd. All rights reserved. Keywords: McEachern’s Deathtrap Cave; Southeastern Australia; Bone breakage; Pitfall trap; Taphonomy 1. Introduction This article describes the post-depositional modifi- cation of a bone assemblage from a pitfall cave fossil deposit from southeastern Australia. The objectives of this taphonomic study were to investigate those pro- cesses of bone modification that have been important in the dispersal, destruction and preservation of bone in Trench A of the McEachern’sDeathtrap Cave, G49 fossil deposit. 1.1. Post-depositional modification of bone Post-depositional processes impart modifications to vertebrate assemblages following burialin a contain- ment area (i.e. the cave), which may overprint previously existing predatory signatures, thereby obscuring their origins [11]. The effects of scavenging, which may occur prior to burial,are difficult to distinguish from preda- tory activity [1].Rodentgnawing ofbone [9,14] is a readily identifiable form of scavenging and is recognised by distinctgrooveson bone formed by the rodents’ incisors.In Australia, otherforms of scavenging are recognised as a result of the activity ofthe marsupial carnivore Sarcophilus sp., the Tasmanian Devil [28]. Once buried, bone is subject to biological and chemi- cal modification, which leads to the breakdown of the bone’s mineral and organic components [8,34]. At an early stage ofburial,insectgnawing also may be an importantmodifierof bone [7].Acidic (low pH) en- vironmentsmay dissolveor etch bone,dentineand enamelsurfaces, and are usually the result of organic acids in the geological environment [34]. Another form of acid corrosion, localised in its activity, results from 1 Formerly at School of Geosciences, Monash University, Clayton, Victoria 3800, Australia. E-mail address: kos@erdw.ethz.ch (A.M. Kos). Journal of Archaeological Science 30 (2003) 781–796 SCIENCE Journal of Archaeological http://www.elsevier.com/locate/jas SCIENCE Journal of Archaeological http://www.elsevier.com/locate/jas 0305-4403/03/$ - see front matter 2003 Elsevier Science Ltd. All rights reserved. doi:10.1016/S0305-4403(02)00252-2