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Geoarchaeological finds below Liang Bua (Flores, Indonesia): A split-level cave system for Homo floresiensis?
... 7 suids -ancient DNA from a pig tooth excavated in Liang Bua suggests S. celebensis was present by ∼7 ka (Larson et al., 2007), thus before the arrival of Austronesian-speaking farmers and the beginning of the "Neolithic" in this region (∼4 ka) (Bellwood, 2013(Bellwood, , 2017. A carbonate coating on a skull fragment from an unidentified, but presumably introduced, suid species (retrieved from a sinkhole deposit), also yielded a U-series age of 28 ± 5 ka (Gagan et al., 2015). Both of these dates are in need of reassessment, however, especially given the recent major revisions to the stratigraphic sequence at Liang Bua (Sutikna et al., 2016). ...
The Indonesian island of Sulawesi harbours numerous early rock paintings of the endemic Sulawesi warty pig ( Sus celebensis ). Several S. celebensis images, including one dated to at least 45,500 years ago (ka), portray these suids with an anatomical character not observed in the living species: a pair of teat‐like protuberances in the neck area. This feature seems to be most consistent morphologically with neck “wattles”, cutaneous appendages only manifested in modern domestic swine ( Sus scrofa ) and some other domesticated ungulates (e.g. goats). The notion that the trait portrayed by the Late Pleistocene artists is a domestication character is clearly contentious. We therefore consider: (1) whether we have misidentified the trait – a common problem in rock art analysis; (2) whether wattles are a genuine domestication trait; and (3) if so, whether the notion that Pleistocene people domesticated S. celebensis is plausible. A clear resolution to all of these problems evades us; however, our investigation of this anomaly in the ancient rock art poses important questions about the nature and complexity of early human–pig relations in this island.
Islands have long been recognized as distinctive evolutionary arenas leading to morphologically divergent species, such as dwarfs and giants. We assessed how body size evolution in island mammals may have exacerbated their vulnerability, as well as how human arrival has contributed to their past and ongoing extinctions, by integrating data on 1231 extant and 350 extinct species from islands and paleo islands worldwide spanning the past 23 million years. We found that the likelihood of extinction and of endangerment are highest in the most extreme island dwarfs and giants. Extinction risk of insular mammals was compounded by the arrival of modern humans, which accelerated extinction rates more than 10-fold, resulting in an almost complete demise of these iconic marvels of island evolution.
Simple Summary
In the early 1980s, the late Colin Groves (1942–2017), a noted taxonomist and suid specialist, proposed that the Sulawesi warty pig (Sus celebensis), an endemic suid from the Indonesian island of Sulawesi, had been independently domesticated by a pre-Neolithic human population (that is, a non-sedentary foraging society) and translocated by watercraft to other islands in the region. This conflicts with two central premises in our understanding of the origins of animal domestication: (1) that the wolf was the only animal domesticated by hunter-gatherers prior to the Neolithic farming transition around 12,000–10,000 years ago; and (2) that the beginnings of pig domestication were inextricably tied to the advent of crop-raising and settled agrarian communities. This paper considers whether it is plausible to suggest that a non-sedentary population of hunter-gatherers could have domesticated a wild suid. It is proposed that pre-agricultural foragers could have established a close association with wild-living members of S. celebensis that was similar to the relationship of interspecies companionship that is purported to have existed between Late Pleistocene foragers and juvenile wolves, according to some, leading to the first domesticated dogs.
Abstract
The Sulawesi warty pig (S. celebensis) is a wild and still-extant suid that is endemic to the Indonesian island of Sulawesi. It has long been theorised that S. celebensis was domesticated and/or deliberately introduced to other islands in Indonesia prior to the advent of the Neolithic farming transition in the region. Thus far, however, there has been no empirical support for this idea, nor have scientists critiqued the argument that S. celebensis was a pre-Neolithic domesticate in detail. Here, it is proposed that early foragers could have formed a relationship with S. celebensis that was similar in essence to the close association between Late Pleistocene foragers in Eurasia and the wild wolf ancestors of domestic dogs. That is, a longstanding practice of hunter-gatherers intensively socialising wild-caught S. celebensis piglets for adoption into human society as companion animals (‘pets’) may have altered the predator–prey dynamic, brought aspects of wild pig behaviour and reproduction under indirect human selection and control, and caused changes that differentiated human-associated pigs from their solely wild-living counterparts.
The thousands of islands east of Huxley’s Line have never formed a single land mass or been connected to Sunda or Sahul. The earliest records of hominins in this area are stone tools recovered from Pleistocene deposits on Flores and Sulawesi. Subsistence by these hominins as well as the later subsistence patterns exhibited by Homo floresiensis suggest that exploitation of marine resources was, at best, rare and opportunistic. Likewise, the fragmentary hominin remains recovered from Late Pleistocene deposits from Callao Cave in the Philippines exploited large game at the expense of marine resources. In contrast, the earliest zooarchaeological records of modern humans are dominated by marine fish and shellfish and include the earliest evidence of pelagic fishing using shell tools, implying complex fish-capture technology. Pleistocene lithic assemblages on these islands are unspecialized, indicating reduction of predominantly locally available stone to produce flakes and irregularly retouched pieces. By the terminal Pleistocene, records of human subsistence on very small islands indicate almost total reliance on marine foods for protein. We propose that strong links exist between subsistence strategies and dispersal throughout Wallacea, with subsistence strategies available to pre-sapiens hominins in the region being a major limiting factor in their dispersal.
This chapter reviews the environmental and cultural correlations for the two archaic hominin species in Indonesia: Homo erectus and Homo floresiensis. From an archaeological perspective, it is clearer now than in the mid-1990s that these archaic Southeast Asian hominins made and used tools of stone, bone, and shell, and butchered animals. The chapter discusses the lithic industries that could, with some fertile imagination at that time, be associated with Homo erectus in various regions of Island Southeast Asia, comparing them with the undoubted handiwork of this species in China. It also discusses these industries in terms of two technological categories: the so-called 'chopper/chopping-tool industries' characterized by the Javan Pacitanian industry and reputed to be the handiwork of Homo erectus, and the so-called 'pebble and flake industries' deemed more characteristic of early Homo sapiens.
The origin and timing of the introduction of pigs and pottery into New Guinea are contentious topics. Arguments have centred on whether domestic pigs and pottery technology entered New Guinea following the ‘Austronesian expansion’ from Southeast Asia into Island Melanesia, c. 3,300 calBP, or in the early to mid-Holocene. We review the history of the debate and present new dates on pig bone and pottery contexts from archaeological sites, including Taora and Lachitu, on the north coast of mainland Papua New Guinea (PNG), where earlier data supported claims for early pig and pottery. We argue that theoretical positions about ‘Neolithic’ origins in PNG influenced the relative willingness to accept early dates prima facie and conclude that current evidence shows neither pig nor pottery arrived before 3,000 calBP in mainland PNG.
Cave guano derived from insectivorous bats and birds contain unique geochemical and mineralogical signatures. We investigated the mineralogy , pH, C, N and metal abundance patterns of cave guano spatially and temporally (with depth) along a W–E transect in Malaysia and Palawan from five remote cave sites, each housing large populations of bats and Aerodramus spp.(cave swiftlets). Guano deposits were rich in phosphate and/or sulphate minerals (e.g., gypsum, bassanite) with leucophos-phite, spheniscidite, and variscite present in most profiles. Metal abundances measured from modern and ancient bat guano revealed high concentrations of transition metals relative to the local environment. Highly enriched metals, however, were associated with phosphate rather than sulphate minerals. Copper and Zn were enriched in all profiles, whereas other metals were associated with specific caves consistent with known local mineral resources. For example, Sn, Pb, and Rb were particularly enriched in Batu Cave, located in the Peninsular Malaysian granitic tin belt, whereas Ni and Cr were high in regions associated with ultramafic ophiolites and Ni-laterites found on Palawan.
Karstic sites have great potential for yielding data regarding changes in faunal communities in the Pleistocene of Southeast Asia. In this region, the majority of fossil-bearing deposits are karstic breccias, which generally demonstrate a complicated sedimentary history. While most of the mammalian assemblages recovered in these deposits are only composed of isolated teeth, their study remains essential for reconstructing paleoecology and paleoclimatology of the region. We analyzed the assemblages recovered in three mainland and two insular karstic sites: Tam Hang South and Nam Lot in northern Laos, Duoi U'Oi in northern Vietnam, Punung in central Java and Sibrambang in western Sumatra and obtained new chronologies for three of these sites so that their significance could be discussed within their correct chronological context. The resulting age ranges place the sites in MIS5 and MIS4. The comparative analysis of the faunas, in terms of taphonomy, taxonomic diversity and abundance, and mortality profiles (Cervus unicolor, Sus scrofa, Sus vittatus, rhinocerotids and Tapirus indicus), reveals marked differences in prey–predators (carnivores and/or humans) relationships in relation to habitat. The study of homininesbearing sites (Punung, Nam Lot, Duoi U'Oi) allows us to emphasize different interactions with large carnivores (felids, hyaenids, canids).
Archaeologists have long been puzzled by the appearance in Europe ∼40-35 thousand years (kyr) ago of a rich corpus of sophisticated artworks, including parietal art (that is, paintings, drawings and engravings on immobile rock surfaces) and portable art (for example, carved figurines), and the absence or scarcity of equivalent, well-dated evidence elsewhere, especially along early human migration routes in South Asia and the Far East, including Wallacea and Australia, where modern humans (Homo sapiens) were established by 50 kyr ago. Here, using uranium-series dating of coralloid speleothems directly associated with 12 human hand stencils and two figurative animal depictions from seven cave sites in the Maros karsts of Sulawesi, we show that rock art traditions on this Indonesian island are at least compatible in age with the oldest European art. The earliest dated image from Maros, with a minimum age of 39.9 kyr, is now the oldest known hand stencil in the world. In addition, a painting of a babirusa ('pig-deer') made at least 35.4 kyr ago is among the earliest dated figurative depictions worldwide, if not the earliest one. Among the implications, it can now be demonstrated that humans were producing rock art by ∼40 kyr ago at opposite ends of the Pleistocene Eurasian world.
Significance
The population that has become known as Homo floresiensis has been described as “the most extreme human ever discovered.” Specimen LB1 from Liang Bua Cave is unusual, but craniofacial and postcranial characteristics originally said to be diagnostic of the new species are not evident in the other more fragmentary skeletons in the sample that resemble other recent small-bodied human populations in the region (including the Andaman Islands, Palau, and Flores itself). Here we demonstrate that the facial asymmetry, small endocranial volume, brachycephaly, disproportionately short femora, flat feet, and numerous other characteristics of LB1 are highly diagnostic of Down syndrome, one of the most commonly occurring developmental disorders in humans and also documented in related hominoids such as chimpanzees and orangutans.
Seventeen Middle Pleistocene crania from the Sima de los Huesos site (Atapuerca, Spain)
are analyzed, including seven new specimens. This sample makes it possible to thoroughly
characterize a Middle Pleistocene hominin paleodeme and to address hypotheses
about the origin and evolution of the Neandertals. Using a variety of techniques, the
hominin-bearing layer could be reassigned to a period around 430,000 years ago.
The sample shows a consistent morphological pattern with derived Neandertal features
present in the face and anterior vault, many of which are related to the masticatory
apparatus. This suggests that facial modification was the first step in the evolution of
the Neandertal lineage, pointing to a mosaic pattern of evolution, with different anatomical
and functional modules evolving at different rates.
The evolution of the Torcas cave system (Sierra de Atapuerca) is analysed in order to shed light on the formation of the Atapuerca archaeological sites and human occupation in the area, critical for identifying the paths of the first human dispersal into Europe. The geomorphological analysis of the endokarst system and the regional base levels has revealed a multilevel cave system, with drainage directions from south to north, where old karst springs fed the Pico River. Using morphological and topographic evidence we have correlated the fluvial terraces situated at relative heights of +84–80 m and +78–70 m above the Arlanzón River (main course), with the first and second cave levels, respectively, both of Early Pleistocene age. The fluvial levels T4 (+60–67 m) and T5 (+50–54 m) are linked with the third level (Early–Middle Pleistocene), which contains fluvial deposits probably related to terrace T6 (+44–46 m). Progressive fluvial incision allowed humans to gain access to the cave system through several entrances from ~1.22 Myr until the end of the Middle Pleistocene, when these cave entrances became filled, forming the most interesting hominid-bearing deposits in Europe.
The Sima de los Huesos site of the Atapuerca complex near Burgos, Spain contains the skeletal remains of at least 28 individuals in a mud-breccia underlying an accumulation of the Middle Pleistocene cave bear (Ursus deningeri). We report here on new high-precision dates on the recently discovered speleothem SRA-3 overlaying human bones within the Sima de los Huesos. Earlier analyses of this speleothem by TIMS (thermal-ionization mass-spectrometry) showed the lower part to be indistinguishable from internal isotopic equilibrium at the precision of the TIMS instrumentation used, yielding minimum age of 350 kyr (kyr ¼ 10 3 yr before present). Reanalysis of six samples of SRA-3 by inductively-coupled plasma-multicollector mass-spectrometry (ICP-MS) produced high-precision analytical results allowing calculation of finite dates. The new dates cluster around 600 kyr. A conservative conclusion takes the lower error limit ages as the minimum age of the speleothem, or 530 kyr. This places the SH hominids at the very beginnings of the Neandertal evolutionary lineage. Published by Elsevier Ltd.
Dating Cave Paintings
A number of caves in Europe contain exquisite ancient art. Most of the art has been thought to be produced during the time of last glaciation by recently arrived modern humans, but dating of the art has been problematic because the art contains only minimal amounts of carbon for radiocarbon dating. Pike et al. (p. 1409 ; see the cover; see the Perspective by Hellstrom ) have now obtained U-series dates on the calcite crusts that formed over the art from 11 caves in northwestern Spain. The ages from three caves are older than 35,000 years ago, and one dates to nearly 41,000 years ago. The earliest art used primarily red and was relatively formless; animal depictions appeared later. This dating is near the time of the arrival of modern humans and, because Neandertals were also present, complicates identifying the artists.
In this article a topographical description of the Cueva Mayor–Cueva de Silo cave system is provided, including a more detailed topography of the Sala de los Cı́clopes–Sala de las Oseras–Sima de los Huesos sector. The history of the excavations and discoveries of human and carnivore fossils in Sima de los Huesos and adjacent passages is briefly reported, as well as the increase, throughout the succeeding field seasons, of the human collection and changes in the relative representation of the different skeletal elements and major biases. The carnivore assemblage structure is also considered. Examining the characteristics of the bone breccia, and the current and ancient karst topography, different alternative accesses are discussed for the accumulation of carnivores and humans in the Sima de los Huesos. Taking into account all the available information, an anthropic origin for the accumulation of human fossils seems to us to be the most likely explanation.
Evidence from Liang Bua, a limestone cave on the island of Flores in East Indonesia, provides a unique opportunity to explore the long term relationship between hominins and their environment. Occupation deposits at the site span ∼95 ka and contain abundant stone artefacts, well preserved faunal remains and evidence for an endemic species of hominin: Homo floresiensis. Work at the site included detailed geomorphological and environmental analysis, which has enabled comparisons to be drawn between changes in the occupational intensity in the cave, using stone tool and faunal counts, and changes in the environmental conditions, using the characteristics of the sedimentary layers in the cave and speleothem records. These comparisons demonstrate that H. floresiensis endured rapidly fluctuating environmental conditions over the last ∼100 ka, which influenced the geomorphological processes in the cave and their occupational conditions. The intensity of occupation in the cave changed significantly between 95 and 17 ka, with peaks in occupation occurring at 100–95, 74–61 and 18–17 ka. These correlate with episodes of channel formation and erosion in the cave, which in turn correspond with high rainfall, thick soils and high bio-productivity outside. In contrast, periods of low occupational intensity correlate with reduced channel activity and pooling associated with drier periods from 94 to 75 and 36 to 19 ka. This apparent link between intensity of hominin use of the cave and the general conditions outside relates to the expansion and contraction of the rainforest and the ability of H. floresiensis to adapt to habitat changes. This interpretation implies that these diminutive hominins were able to survive abrupt and prolonged environmental changes by changing their favoured occupation sites. These data provide the basis for a model of human–environment interactions on the island of Flores. With the addition of extra data from other sites on Flores, this model will provide a greater understanding of H. floresiensis as a unique human species.
The formation of authigenic minerals in cave sediments can be used to reconstruct the paleochemical conditions that prevailed in the past, and in this way to assess the completeness of the archaeological record. Previous studies indicated that the major driving mechanisms for chemical diagenesis in prehistoric caves that result in the formation of authigenic minerals, are the degradation of bat guano and the local hydrology. We therefore investigated contemporary bat guano deposits in caves and the sediments directly below such deposits. The emerging patterns show that the formation of authigenic minerals occurs under acidic conditions within tens of years. The availability of phosphate, Al, K, and Fe increases with increasing organic matter degradation, while the availability of nitrogen and sulfur decreases. Insectivorous bat guano contains larger amounts of phosphate and is more acidic than fruit bat guano. In the first stages of diagenesis micro-chemical environments form within the degrading bat guano that result in the formation of a wide variety of authigenic minerals. During advanced stages of diagenesis steady state conditions are achieved resulting in authigenic mineral assemblages being dominated by one mineral type at the same locale. This is reminiscent of known distributions of authigenic minerals in prehistoric cave sediments. Under the acidic conditions produced by degrading bat guano deposits, calcareous artifacts and bones are not expected to persist for long periods of time, unless there is a lot of calcite in the sediments that could buffer the sediment water pH. Guano itself is not likely to be preserved. Periods of cave abandonment can be inferred from the presence of authigenic minerals in the sediments as it is during these times that bats mainly occupy the cave. The occurrence of certain authigenic minerals in open-air sites may serve as evidence for areas rich in organic matter containing phosphate (i.e., animal enclosures, latrines, sewers, trash pits) and/or bones. As the degradation process is rapid, the use of authigenic minerals to identify these loci is relevant to almost all archaeological, as well as historical sites.
The sedimentation conditions and diagenetic processes of biogenic and inorganic carbonates are such that the assumptions of a closed system evolution and the absence of initial Th invoked in classical 238U–234U–230Th dating methods are very often not fulfilled for such material. This problem is of interest for all studies requiring accurate dating of corals or aragonite-rich sediments as in palaeoclimatology or neotectonics. Extending the approach of Henderson and Slowey [Nature 404 (2000) 61–66], we propose a consistent model that takes into account possible initial 230Th excess and where continuous selective redistribution (gain or loss) of 234U, 234Th and 230Th is controlled by recoil processes. This model applied to Quaternary marine terraces in Barbados, Marie Galante (Lesser Antilles arc) and Pacific islands, is able to explain the large scatter in isotopic compositions observed in the series of cogenetic corals or sediments. We show that recoil processes generally tend to increase the (234U/238U) and (230Th/234U) ratios with time, leading to an overestimation of the apparent ages calculated using classical methods. On the basis of simple assumptions (identical ‘marine’ initial (234U/238U)0 and (230Th/232Th)0 ratios), we propose a method for calculating a best estimate of the age of cogenetic series. Our model offers an alternative way to date old reef terraces where corals are almost systematically altered and where classical dating methods do not apply. It may also explain the apparent variations of the (234U/238U) seawater initial ratio estimated from corals formed in the last 300 ka and the apparent uncoupling between sea-level highstands and high-latitude Northern Hemisphere summer insolation. Our set of equations can be applied to all weathering processes where the mobility of U-series isotopes is controlled by recoil.
A proposed new term ethnophoresy defines a Late Quaternary biological process that occurs when organisms are able to breach geographical barriers and disperse to new areas by hitching a ride in human vessels or cargo. In this paper a combination of literature analysis, historical research and original fieldwork is used to review the impact of ethnophoresy / anthropogenic animal translocation from ancient times to the present on the vertebrate zoogeography of Wallacea, New Guinea and the Northern Melanesian Islands, referred to collectively as the Circum New Guinea Archipelago. The focus of the paper is on translocated wild rather than domesticated vertebrates.The processes through which these species have been either unwittingly, accidentally or deliberately translocated to new areas are reviewed. Three principal categories of introduced wild species are recognised. These include stowaways, ethnotramps and incidentals. Ethnotramps include economically and culturally favoured animals such as Rusa Deer Cervus timorensis, Long-tailed Macaque Macaca fascicularis, and various civets, cuscuses, wallabies, cassowaries and wild-caught cage birds that are commonly carried around with humans. Stowaways tend to be smaller species such as shrews, rats or herpetofauna that conceal themselves or their eggs in vessels and cargo. While the Oriental region (or broader Indo-Malayan zoogeographic region) appears to have furnished parts of the Circum New Guinea Archipelago with around 58 introduced wild terrestrial vertebrates, translocation from the latter region has had negligible impact on the zoogeography of the former. Some Wallacean islands and New Guinea, however, have been a significant source of species introduced within the Circum New Guinea Archipelago. While vertebrate translocation appears to be largely a Holocene phenomenon, several New Guinea marsupials appear to have been exported to surrounding islands in the Late Pleistocene, with the earliest suspected translocation being that of the Northern Common Cuscus Phalanger orientalis to New Ireland between 10,000 and 20,000 years ago. It is postulated that some ancient human influences may be under-recognised due to the ambiguity of the evidence. An appendix presents some contemporary and suggested new terms in ethnozoology and biogeography.
In this study, a new Early Pleistocene proximal hand phalanx (ATE9-2) from the Sima del Elefante cave site (TE – Sierra de Atapuerca, Spain), ascribed to Homo sp., is presented and comparatively described in the context of the evolution of the genus Homo. The ATE9-2 specimen is especially important because of the paucity of hand bones in the human fossil record during the Early Pleistocene. The morphological and metrical analyses of the phalanx ATE9-2 indicate that there are no essential differences between it and comparator fossil specimens for the genus Homo after 1.3 Ma (millions of years ago). Similar to Sima de los Huesos and Neandertal specimens, ATE9-2 is a robust proximal hand phalanx, probably reflecting greater overall body robusticity in these populations or a higher gracility in modern humans. The age of level TE9 from Sima del Elefante and morphological and metrical studies of ATE9-2 suggest that the morphology of the proximal hand phalanges and, thus, the morphology of the hand could have remained stable over the last 1.2–1.3 Ma. Taking into account the evidence recently provided by a metacarpal from Kaitio (Kenya) from around 1.42 Ma, we argue that modern hand morphology is present in the genus Homo subsequent to Homo habilis.
Archaeozoological records for seven occupation sites in the highlands of New Guinea are presented and reviewed. The sites were originally excavated between 1959 and 1981. More recent excavations have not documented comparable archaeozoological records. This paper aims to summarise unpublished research, together with some previously published results, for a broader audience, and elicit general trends within the data. Of significance are methodological insights, observations on Pleistocene and Holocene extinctions and the introduction of exotic fauna, and implications for understanding land-use and socio-economic histories during the late Holocene.
Ouwendijk, E.M., Due, R.A., Locatelli, E., Jatmiko & Van den Hoek Ostende, L.W., 2014. Bat cave and Hobbit hole, microbats of Liang Bua (Flores, Indonesia). Alcheringa 38. ISSN 0311-5518Liang Bua is a limestone cave on the island of Flores, Indonesia. Palaeontological and archaeological excavations at this site have unearthed one of the best insular records of fossil bats to date. The assemblage is numerically dominated by the horseshoe bat species Rhinolophus euryotis, followed by the leafnosed bat Hipposideros diadema. In addition to these species, remains of Rhinolophus simplex, Hipposideros sp. cf. H. sumbae, Murina sp. aff. M. florium, Taphozous sp., Kerivoula sp. and Miniopterus sp. have also been recovered. Two taxa found in Liang Bua, Rhinolophus euryotis and Miniopterus sp., are not apparent in the modern bat fauna of Flores. Some specimens, found during the more recent excavations, are known from specific depths. Two age-groups are represented. The stratigraphically oldest is 74-61 ka and includes Murina sp. aff. M. florium and Rhinolophus euryotis. Conversely, the younger, Holocene, assemblage is much more diverse. Despite the relatively small amount of microbat material collected thus far, it displays a higher diversity than the rodents from the site. This is presumably related to the better dispersal ability of bats relative to other, non-volant mammals.Esther Marlous Ouwendijk [[email protected]
/* */] and Lars W. van den Hoek Ostende [[email protected]
/* */], Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands; Rokus Awe Due, and Jatmiko, The National Research and Development Centre of Archaeology, Jl. Raya Condet Pejaten No. 4, Jakarta 12510, Indonesia; Elisa Locatelli [[email protected]
/* */], Ferrara University, Corso Ercole l d'Este 32, 44121 Ferrara, Italy. Received 15.4.2013; revised 22.1.2014; accepted 28.1.2014.
Excavations at Liang Bua Cave yielded a large amount of micromammal remains, the major part of which are murids, and some can be referred to three different species of giant rats. Whilst Papagomys armandvillei is still living on Flores, the other two species, Papagomys theodorverhoeveni and Spelaeomys florensis went extinct late during the Holocene. In this paper, the fossil record of these species at Liang Bua Cave is discussed. These giant murids are a clear example of insular gigantism, and can be seen as end members of the Island Rule. Opposition against the general applicability of this ‘rule’ is mainly based on a scale perspective. The study of giant rats at Liang Bua cave provides new insights in the understanding of human behavior, diet and environment. A strong acme in the number of giant rats in the cave during the Holocene may represent a taphonomical artifact, resulting from Palaeolithic hunting activity.
We have developed techniques for measuring 234U and 230Th on Faraday cups with precisions of 1–3 epsilon units (1 ε-unit=1 part in 104) using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). Using a Thermo-Scientific Neptune with desolvation nebulization, we obtained ionization/transmission efficiencies of 1–2% for both U and Th. We set up protocols to correct for tailing, prepared U and Th gravimetric standards, tested a Th mass fractionation correction procedure based on U isotopes, and identified natural calcite samples likely to be in U–Th isotopic secular equilibrium. The measured atomic ratios, 234U/238U=54.970 (±0.019)×10−6 and 230Th/238U=16.916 (±0.018)×10−6, for these calcite samples were identical within errors (quoted 2σ uncertainties calculated combining all sources of error). Half-life values calculated from these ratios are consistent with previous values, but have much smaller errors: 245,620±260 a for 234U and 75,584±110 a for 230Th (quoted 2σ uncertainties calculated using all sources of error). In calculating a 230Th age, some of the systematic errors included in estimating the full error in the half-lives effectively cancel. Removing these uncertainties (uncertainty in the 238U half-life value, uncertainty in our gravimetric uranium and thorium standards, and uncertainty in the absolute isotopic composition of the uranium standard), yields effective uncertainties for the purposes of 230Th dating of ±70 a for the 234U half-life value and ±30 a for the 230Th half-life value. Under ideal circumstances, with our methods, the 2σ uncertainty in age, including uncertainty in half-life values is ±10 a at 10 ka, ±100 a at 130 ka, ±300 a at 200 ka, ±1 ka at 300 ka, ±2 ka at 400 ka, ±6 ka at 500 ka, and ±12 ka at 600 ka. The isotopic composition of a sample with an age <800 ka can clearly be resolved from the isotopic composition of a sample in secular equilibrium, assuming closed system behavior. Using these techniques, we analyzed a Sanbao Cave (Hubei, China) stalagmite that formed between 510 and 640 ka ago. As the half-life values were determined independent of the Sanbao Cave ages, the observed co-variation between stalagmite δ18O and Northern Hemisphere summer insolation is consistent with accurate ages and half-life values.
Potentiometric measurements with a glass electrode combined with solubility determinations of COâ(g) have indicated that, at 25°C in 3 M NaClOâ medium with (U(VI)) < 0.05 M and log (HCOââ») greater than or equal to -1.2, the prevailing form of uranium (VI) is the species UOâ(COââsub 3//sup 4 -/ (= UOâ(OH)â(COâ)â/sup 4 -/). On acidification of UOâ(COâ)â/sup 4 -/, and before solid uranyl carbonates start to precipitate, a polynuclear complex (UOââsub 3/(COâ)â/sup 6 -/ (= UOâ)â(OH)ââ(COâ)â/sup 6 -/) was found to form according to 3UOâ(COâ)â/sup 4 -/ + 3COâ(g) + 3HâO reversible (UOâ)â(COâ)â/sup 6 -/ + 6HCOââ» with the equilibrium constant, log *..beta../sub 3,12,6/ = -6.43 +- 0.08. No evidence for the species UOâ(COâ)â/sup 2 -/ or mixed species (UOâ)/sub p/(OH)/sub q/(COâ)/sub r/ was obtained in the experimental range investigated: 10â»Â³ less than or equal to (U(VI)) less than or equal to P/sub COâ/ less than or equal to 1 atm, and -3.0 less than or equal to log (HCOââ») less than or equal to -0.7. The ¹³C NMR spectra of the two complexes indicate the presence of three equivalent groups in the mononuclear complex and two different carbonate sites with the ratio 1:2 between the integrated intensities in the trinuclear complex. The NMR data are compatible with a structure containing both bridging and terminal carbonate groups.
Nature, 406, 713–716 (2000). In this Letter, a statement on page 715 that the eustatic sea level Δζeus(t) differs from the ice-volume-equivalent sea level Δζe(t) is erroneous. We thank W. R. Peltier for drawing this error in interpretation to our attention. The two definitions were initially introduced to distinguish changes in sea level that were the result of ice mass being added to the oceans from other changes caused by thermal expansion, for example.
To reconstruct global sea-level changes in the past mainly U-series dating of exposed fossil reef corals is used. With the development of the TIMS technology, on the one hand the analytical precision improved by several orders of magnitude, on the other hand another problem appeared: Up to 90% of the corals show initial (234U/238U) activity ratios (denoted as delta234U(T)) significantly higher than the ratio measured on modern day seawater and recent corals. This is ascribed to post depositional diagenesis and clear evidence for open system behavior. Therefore the established opinion is that the accuracy of U-series ages of fossil corals is more limited due to isotopic anomalies than to analytical precision. Several workers have tried to identify disturbed corals by mineralogical characteristics, but the isotopic systems seem to be more sensitive to diagenetic change than any other geochemical parameter. It has also been tried to find correlations between the delta234U(T) values and other isotopic parameters and various scenarios that produce elevated delta234U(T) values have been developed, but until now all those models have neither been validated nor disproved. For this reason only U-series ages of corals with delta234U(T) lying within a specific range of 149 ± 4 ppm or concordant 231Pa-ages are assumed to be strictly reliable, but even when corals as pristine as possible are sampled, only a few meet this criterion. We developed a model where elevated delta234U(T) values are explained by exchange of dissolved uranium between the coral and the waters percolating through the reef. By varying degree of alteration in different pieces of one and the same coral the model produces characteristic isochrones and enables to calculate an isochron age that is in accordance with the true age of the coral. The model was verified with six Porites corals collected from two fossil reef terraces at Aqaba, Jordan (northern Red Sea). These corals show a high degree of alteration and TIMS measurements on different parts of one coral show a clear correlation between delta234U values and (230Th/238U) activity ratios. For five corals precise isochron ages and respective 2sigma-errors (Monte-Carlo-Simulation) were calculated. The application of isochron dating may increase the number of reliable U-series ages of fossil corals, that are urgently needed for the reconstruction of global sea-level changes.
Karst processes typically occur in carbonate rocks, such as limestone or dolomite. They occur all over the world everywhere where carbonate rocks are exposed and submitted to rain and/or water circulation. The karstification of carbonate rocks-bearing landscapes leads to a variety of surface and subsurface features. In tropical and sub-tropical areas as it is the case in Southeast Asia, the mature karst landscapes display a typical morphology called tower karst. Beneath the surface, the complex underground drainage systems contribute to an extensive network of caves and caverns, which may be filled with breccia. The history of sedimentary cave infilling is often complicated due to alternating cycles of infilling/removing phases through time, driven by climate/tectonic/eustatic changes. We present results from our research in Vietnam and Laos. We emphasise that both modern and fossil alluvial terraces and cave entrances/exits, evolve together, and that the caves at progressively higher elevations also have older periods of formation. The oldest breccias and sedimentary deposits are on the upper part of the network, whereas the youngest ones are often close to the modern alluvial plain. These processes of formation are in many respects very similar to those of the fluvial terraces formed during the drop of the alluvial plain, showing a stair-like morphology. Additionally, the alternation of infilling and erosion is strongly linked to the progressive downcutting of the alluvial plain that leads to a major change in both, water circulation and sedimentary deposits. The bone-bearing breccias, formed by typical sedimentary processes, yield vertebrate assemblages, often essentially composed of isolated teeth from middle- to large-sized mammals (Artiodactyla, Perissodactyla, Proboscidea, Carnivora, Rodentia, Primates). In terms of zoogeography, the continental Southeast Asian mammals belong to the Indochinese Subregion. After a brief review of the evolution of the faunas throughout the Pleistocene, we present a biochronological framework of the transition between the Middle Pleistocene and the Late Pleistocene, on the basis of our research in the karsts of Vietnam (Duoi U’Oi and Ma U’Oi sites) and Laos (Tam Hang site).
L'introduction du cochon domestique ou sauvage dans des regions a l'est de la ligne Wallace a conduit a l'apparition de 4 types differents en dehors des limites naturelles du genre. L'un d'entre eux etait d'origine hybride. L'article decrit les caracteres de chacun de ces types et une etude systematique du genre Sus.
Elevated concentrations of U are found in agricultural drainage waters from the San Joaquin Valley, CA, which are often disposed of in evaporation basins that are frequented by waterfowl. To determine the factors that affect aqueous U concentrations in the basins, sorption experiments with U(VI) were performed at various COâ partial pressures, dissolved Ca, Mg, and P concentrations, and carbonate alkalinities. Synthetic waters, comparable in inorganic constituents to irrigation and drainage waters, were prepared, spiked with 0.1 (soil) and 2 mg U(VI) Lâ»Â¹ (synthetic goethite), and analyzed for U, P (when applicable), and major ions. Total chemical analyses were input into the computer program FITEQL to determine U(VI) speciation and generate U(VI) adsorption constants with the diffuse layer model (also referred to as the two-layer model). Maximum adsorption occurred in solutions with low carbonate alkalinities (
Initial (234U/238U) activity ratios higher than those expected from closed system evolution of seawater are an outstanding problem in U-series dating of fossil reef corals. The increased activity ratios are ascribed to post-depositional diagenesis. We analysed six Last Interglacial and one Holocene coral of the genus Porites collected near the northern end of the Gulf of Aqaba (northern Red Sea) together with three recent corals from this location as a modern reference. While the values measured on the recent samples show no deviation from expected values, the Holocene and Last Interglacial corals display highly elevated (234U/238U) activity ratios as well as increased 238U and 232Th concentrations. (234U/238U) activity ratios are strongly correlated with (230Th/238U) and total uranium content. A model assuming different degrees of uranium addition and subsequent loss in different sub-samples of one coral produces straight lines (isochrons) on a (234U/238U)–(230Th/238U) plot and predicts that the true age of the coral can be calculated by intersecting this isochron with the seawater evolution curve. We used the strong correlation detected in the Aqaba corals to calculate isochron ages. The isochron age of the Holocene coral (3116 +167 −156 yr) is concordant with its calibrated 14C age (2963 +92 −103 yr). The ages of the Last Interglacial corals are between 121 (+6.7 −5.3) and 121.9 (+7.0 −6.3) kyr for a higher terrace (7–10 m asl) and 106.4 (+8.9 −8.1) and 117.1 (+19.7 −15.3) kyr for a lower terrace (4–5 m asl). One Last Interglacial coral with an aragonite content of ∼85% could not be dated. The elevation and ages of the fossil terraces are consistent with existing sea level reconstructions from the Red Sea.
This study aimed to further test the method, reported by St Pierre et al. (2009), to develop robust chronologies of deposits in limestone caves through U/Th (Uranium/Thorium or U-Series) dating of soda straw stalactites. The chronology of fossil bearing deposits at Blanche Cave was further constrained with thermal ionisation mass spectrometry (TIMS) U/Th dating of 17 additional soda straw stalactite samples, and results were compared to recalibrated 14C ages of charcoal. The results support the assertion that soda straw stalactites can provide ages close to the time of sediment deposition and may be used as reliable chronological markers, particularly for periods reaching or beyond the radiocarbon dating limit. The application of an enhanced cleaning technique facilitated the reduction of detrital Th in samples, significantly increasing age accuracy and precision. Additionally U/Th age accuracy and precision was increased through the application of site-specific measured U/Th ratios to correct for the detrital 230Th component in samples.
Potentiometric measurements with a glass electrode combined with solubility determinations of CO2(g) have indicated that, at 25°C in 3 M NaClO4 medium with [U(VI)] < 0.05 M and log [HCO3-] ≥ -1.2, the prevailing form of uranium(VI) is the species UO2(CO3)34- (=UO2(OH)6(CO2)24-. On acidification of UO2(CO3)34-, and before solid uranyl carbonates start to precipitate, a polynuclear complex (UO2)3(CO3)66- (=(UO2)3(OH)12(CO2)66-) was found to form according to 3UO2(CO3)34- + 3CO2(g) + 3H2O ⇄ (UO2)3(CO3)66- + 6HCO3- with the equilibrium constant, log *β3,12,6 = -6.43 ± 0.08. No evidence for the species UO2(CO3)22- or mixed species (UO2)p(OH)q(CO3)r was obtained in the experimental range investigated: 10-3 ≤ [U(VI)] ≤ 0.03 M, 0.1 ≤ PCO2 ≤ 1 atm, and -3.0 ≤ log [HCO3-] ≤ -0.7. The 13C NMR spectra of the two complexes indicate the presence of three equivalent carbonate groups in the mononuclear complex and two different carbonate sites with the ratio 1:2 between the integrated intensities in the trinuclear complex. The NMR data are compatible with a structure containing both bridging and terminal carbonate groups.
The Late Pleistocene Flores fauna shows a pattern observed on many other islands. It is neither aberrant nor exclusive, but the result of non-random selective forces acting upon an impoverished and disharmonic insular fauna. By comparing the Flores vertebrate fauna with other fossil insular biotas, it is apparent that the evolution of Homo floresiensis is part of a general pattern affecting all the inhabitants of Pleistocene Flores. Vertebrate evolution on Flores appears to have been characterized by phylogenetic continuity, low species richness and a disharmonic fauna. All three aspects stem from the isolated position of the island and have resulted in the distinct morphological characteristics of the Flores fauna. Evidence reviewed herein shows that features exhibited by H. floresiensis, such as small stature, a small brain, relatively long arms, robust lower limbs and long feet, are not unique, but are shared by other insular taxa. Therefore, the evolution of H. floresiensis can be explained by existing models of insular evolution and followed evolutionary pathways similar to those of the other terrestrial vertebrates inhabiting Pleistocene Flores.
The Singa (Sudan) calvaria has been interpreted previously as a terminal Pleistocene modern human fossil, perhaps related to the Bushman of Southern Africa. Here we report new mass-spectrometric U–Th dates for the calcrete deposit enclosing the fossil teeth and the calvaria itself and new electron spin resonance (ESR) dates for associated dental materials. The new data constrain the age of the hominid to at least 133±2 ka. Together with the preferred linear uptake (LU) ESR dates, the U–Th data confirm that the intriguing mixture of modern and archaic characteristics in the Singa specimen date from isotope stage 6. Far from being a modern human fossil, it represents a rare example of an archaic African population which may have been ancestral to all modernHomo sapiens.
Gibbs free energies, enthalpies and entropies of 42 dissolved uranium species and 30 uranium-bearing solid phases have been critically evaluated from the literature and estimated when necessary for 25°C. Application of the data shows that the uranium in natural waters is usually complexed. At typical concentrations of chloride, fluoride, phosphate and sulfate, uranous (U4+) fluoride complexes are important in anoxic waters below pH 3–4. An intermediate Ehs (between about +0.2 and −0.1 V) and pH values 1–7, UO2+ ion may predominate. In oxidized waters, uranyl (U22+) fluoride complexes and uranyl ion predominate below pH 5; from about pH 4 to 7.5, UO2(HPO4)22− is the principal species; while at higher pHs, UO2CO30 and the di- and tri-carbonate complexes predominate. Uraninite [UO2-UO2.25], α-U3O8 and schoepite are the stable uranium oxides and hydroxides in water at 25°C. Coffinite, USiO4 (c), is probably stable relative to UO2(c) when dissolved silica exceeds about 60 ppm (as SiO2). At low Ehs and pH 4–6, the solubilities of stoichiometric crystalline uraninite and coffinite are below roughly 10−4 ppb. But at intermediate Ehs and neutral to alkaline pHs in the presence of phosphate or carbonate, the formation of uranyl phosphate or carbonate complexes can increase the solubilities of these minerals by several orders of magnitude. The uranyl minerals carnotite, tyuyamunite, autunite, potassium autunite and uranophane are least soluble at pHs in the range 5–8.5 and, in the case of carnotite and tyuyamunite, have solubilities as low as 0.2 and 1 ppb uranium, respectively. The autunites and uranophane are usually several orders of magnitude more soluble than this, consistent with their natural occurrences. Sorption of uranyl on to natural materials is maximal in the same pH range of 5–8.5.
Bat droppings accumulate in caves, and the resultant guano contains a stratigraphic record of the environment analogous to the record from lake sediment and peat. The bats forage at night for insects; they return to the cave during the day to sleep and care for their young. They attach themselves to suitable perches in the cave ceiling, and their excrement accumulates on the floor below. Flying requires a lot of energy, and bats of temperate regions consume large numbers of night-flying insects. In some situations the guano can reach a depth of meters in hundreds to thousands of years, and it has a valuable chronostratigraphy. The bat scats occur as small pellets that represent the non-digestible portion of the animal's diet in the preceding few hours; hence the diet provides information about the time of the year the feeding occurred. Bat guano contains, among other things, insect fragments, hair, pollen, and mineral matter. Night-flying insects do not normally visit flowers for the pollen; many species do not eat during the flying phase of their life cycle, and those that do generally are nectar feeders. Although the insects are not after the pollen, they do fly through a pollen-laden environment, and the pollen and dust adheres to their bodies. The insects essentially act as living traps for airborne debris. The bats also are furry pollen traps; during grooming they ingest pollen and dust enmeshed in their fur, and this also is excreted. The pollen in an individual scat contains a record of the atmospheric pollen during a single day in the past. This kind of detail is rarely available from lake sediment. Chemical analysis of individual bat scats in a time series can chart the changing environment caused by agriculture, industry, volcanic dust, and a host of other details that depend only on the cleverness of the researcher. Careful 14C analysis can isolate the times when bats did not use the cave, and that may be useful in interpreting past conditions. If the insect types in the guano change over time, that may provide evidence of changing climate. Pollen was analyzed from guano samples taken from Tumbling Creek Cave near Protem, Missouri, USA. The cave contains a maternal colony of the Grey Bat (Myotis grisescens) that occupies the cave for a short time each year. Scats collected from the base of a 70 cm thick cone of guano yielded an AMS 14C date of 2810 ± 40 yr BP. The fecal material has a crumbly structure below the surface; it was of mahogany color (7.5 YR 2/1 to 3/2) and had no noticeable odor. Guano can be processed like normal sediment, but simple washing in a weak detergent solution followed by acetolysis appears adequate.
Stegodon remains originating from Late Pleistocene layers of the archaeological cave site Liang Bua on the Indonesian Island of Flores, are described as a new endemic dwarf subspecies: Stegodon florensis insularis subsp. nov. Some fossil Stegodon fragments were found in association with the recently described remains of Homo floresiensis, but many occur in levels with high artefact concentrations. The direct ancestor is the larger-sized S. florensis florensis, known from Early Pleistocene and early Middle Pleistocene sites on Flores. The assemblage from Liang Bua comprises mostly dental and skeletal elements of juvenile individuals. S.f. insularis is characterized by an advanced molar ridge formula and diminutive size: on average the molars are 30 per cent smaller in linear dimensions as compared to the ancestral species. Hominin activities are likely to have played a role in the Stegodon bone accumulation at Liang Bua.
The source of excess 234U in fossil corals and its relationship to U-series age determinations has been an outstanding problem in geochronology for more than 20 years. With increasing numbers of U-series isotope measurements in corals, and significant improvements in analytical precision through mass spectrometry, it is increasingly apparent that a substantial fraction of observed isotope ratios cannot be reasonably explained by closed-system decay. Moreover, observations of a positive correlation between 234U/238U and 230Th/238U ratios in corals from the same terrace are difficult to explain. However, the decay of dissolved uranium and α-recoil mobilization of uranium daughters produce particle-reactive 234Th and 230Th, and the coupled addition of these Th isotopes could simultaneously increase coral 234U/238U and 230Th/238U. Here we present a quantitative model, based on decay-dependent redistribution of 234Th and 230Th, permitting calculation of open-system coral ages. These equations provide a general solution to the α-recoil redistribution problem, applicable to any alpha decay series. While measured isotope ratios of corals from the three youngest stratigraphically defined Barbados terraces are inconsistent with closed-system decay, they fall in broadly linear arrays agreeing with model predictions. Isotopic arrays of older Barbados corals, and corals from terraces around the world, are also consistent with model predictions suggesting the open-system model is generally applicable. Corals with extreme isotopic compositions that are impossible to produce by closed-system decay are consistent with the limited range of isotopic compositions predicted by the model at ages older than 600 ka. For corals from a single terrace, 234Th and 230Th redistribution appears to be a source of systematic conventional age error, even for corals with slightly elevated 234U. However, open-system ages are consistent, even for corals with extremely elevated 234U. For the youngest three Barbados terraces, mean open-system terrace ages are consistent with mean conventional terrace ages calculated from pristine samples. If the most accurate conventional ages are from corals with an initial 234U/238U identical to modern seawater, then the open-system model will improve the accuracy of coral U-series age determinations and dramatically increase the number of reliable ages.
Uranium-thorium dating of speleothem calcite has proved to be exceptionally useful in anchoring late Quaternary paleoenvironmental records, and is arguably the most robust geochronometer available over much of this period. Nonetheless, correction for the effect of Th-230 incorporated at the time of deposition is extremely important, and has been approached in a number of ways. The use of stratigraphical constraint, that is the a priori requirement that any axial sequence of true ages must exhibit a monotonic increase away from the outer surface, is surprisingly uncommon given its advantages over other techniques. Here a simple numerical implementation of this technique is described, and contrasted with conventional isochron methods. Current practice in the correction of speleothem age determinations for initial Th is reviewed in the light of continued improvements in analytical precision, and is found to be inconsistent. (c) 2007 Elsevier Ltd. All rights reserved.
