Cave stratigraphies and cave breccias: Implications for sediment accumulation and removal models and interpreting the record of human occupation

AbstractMany of the key debates in archaeology hinge on the chronology and interpretation of data gathered from cave and rockshelter stratigraphies, especially those in karstic limestone environments which are selectively targeted by archaeologists because of their superior preservation characteristics. It has long been recognized that such sites often contain a variety of cemented deposits including cave breccias and that some breccias contain anthropogenic inclusions such as stone artefacts, shell and burnt animal bones. Cementation enhances the survival through time of such brecciated deposits. This can result in chrono-stratigraphic intervals surviving on cave walls and speleothems that are no longer represented in the stratigraphy of cave floors. This has important implications for understanding apparent presence/absence of human occupation and cultural continuity as seen in archaeo-stratigraphy in caves and rockshelters, especially in relation to human migration in the humid tropics in SE Asia and the Pacific, and over Pleistocene to Holocene timescales. Here we discuss localized breccia formation, the erosional processes that leave remnant deposits adhering to walls and speleothems at heights well above current cave floors, and the possible significance of local and regional processes, especially changing base levels, in triggering gutting out phases impacting cave floor sediment architectures. Equally significant in terms of chronological completeness, representativeness and bias is the contribution made by cultural materials encased in older breccias as they erode and are (re-)incorporated into younger accumulating cultural deposits. Case studies from cave sites in Papua New Guinea and Timor Leste are used to illustrate these issues

Pre-bomb marine reservoir variability in the Kimberley region, Western Australia

New ΔR values are presented for 10 known-age shells from the Kimberley region of northwest Australia. Previous estimates of ΔR for the Kimberley region are based on only 6 individual shell specimens with dates of live collection known only to within 50 yr (Bowman 1985a). Here, we describe the results of our recent attempts to constrain ΔR variability for this region by dating a suite of known-age pre-AD 1950 shell samples from the Australian Museum and Museum Victoria. A regional ΔR of 58 ± 17 14C yr for open waters between Broome and Cape Leveque is recommended based on 7 of these specimens. The criteria used to select shells for dating and inclusion in the regional mean are discussed.Copyright Information: http://www.sherpa.ac.uk/romeo/issn/0033-8222

Cave stratigraphies and cave breccias: Implications for sediment accumulation and removal models and interpreting the record of human occupation

Many of the key debates in archaeology hinge on the chronology and interpretation of data gathered from cave and rockshelter stratigraphies, especially those in karstic limestone environments which are selectively targeted by archaeologists because of their superior preservation characteristics. It has long been recognized that such sites often contain a variety of cemented deposits including cave breccias and that some breccias contain anthropogenic inclusions such as stone artefacts, shell and burnt animal bones. Cementation enhances the survival through time of such brecciated deposits. This can result in chrono-stratigraphic intervals surviving on cave walls and speleothems that are no longer represented in the stratigraphy of cave floors. This has important implications for understanding apparent presence/ absence of human occupation and cultural continuity as seen in archaeo-stratigraphy in caves and rockshelters, especially in relation to human migration in the humid tropics in SE Asia and the Pacific, and over Pleistocene to Holocene timescales. Here we discuss localized breccia formation, the erosional processes that leave remnant deposits adhering to walls and speleothems at heights well above current cave floors, and the possible significance of local and regional processes, especially changing base levels, in triggering gutting out phases impacting cave floor sediment architectures. Equally significant in terms of chronological completeness, representativeness and bias is the contribution made by cultural materials encased in older breccias as they erode and are (re-)incorporated into younger accumulating cultural deposits. Case studies from cave sites in Papua New Guinea and Timor Leste are used to illustrate these issues

Polymer Crystallization in 25 nm Spheres

Crystallization within the discrete spheres of a block copolymer mesophase was studied by time-resolved x-ray scattering. The cubic packing of microdomains, established by self-assembly in the melt, is preserved throughout crystallization by strong interblock segregation even though the amorphous matrix block is well above its glass transition temperature. Homogeneous nucleation within each sphere yields isothermal crystallizations which follow first-order kinetics, contrasting with the sigmoidal kinetics normally exhibited in the quiescent crystallization of bulk polymers.Comment: accepted for publication in Physical Review Letters, 2/28/2000; scheduled for 5/1/2000 issu

Improving community health networks for people with severe mental illness : a case study investigation

Introduction Policy drivers in mental health to address personal recovery, stigma and poor physical health indicate that new service solutions are required. This study aimed to understand how connections to people, places and activities were utilised by individuals with severe mental illness (SMI) to benefit health and wellbeing. Methods A five-module mixed-methods design was undertaken in two study sites. Data were collected from 150 network-mapping interviews and 41 in-depth follow-up interviews with people with SMI; in-depth interviews with 30 organisation stakeholders and 12 organisation leaders; and 44 telephone interviews with practitioners. We undertook a three-stage synthesis process including independent lived experience feedback, and a patient and public involvement team participated in tool design, data collection, analysis and write-up. Results Three personal network types were found in our study using the community health network approach: diverse and active; family and stable; formal and sparse. Controlled for other factors we found only four variables significantly associated with which network type a participant had: living alone or not; housing status; formal education; long-term sickness or disability. Diagnosis was not a factor. These variables are challenging to address but they do point to potential for network change. The qualitative interviews with people with SMI provided further understanding of connection-building and resource utilisation. We explored individual agency across each network type, and identified recognition of the importance and value of social support and active connection management alongside the risks of isolation, even for those most affected by mental illness. We identified tensions in personal networks, be that relationships with practitioners or families, dealing with the impact of stigma, or frustrations of not being in employment, which all impact on network resources and well-being. The value of connectedness within personal networks of people, place and activity for supporting recovery was evident in shaping identity, providing meaning to life and sense of belonging, gaining access to new resources, structuring routines and helping individuals ‘move on’ in their recovery journey. Health-care practitioners recognised that social factors were important in recovery but reported system-level barriers (workload, administrative bureaucracy, limited contact time with clients) in addressing these issues fully. Even practitioners working in third-sector services whose remit involved increasing clients’ social connection faced restrictions due to being evaluated by outcome criteria that limited holistic recovery-focused practices. Service providers were keen to promote recovery-focused approaches. We found contrasts between recovery ideology within mental health policy and recovery practice on the ground. In particular, the social aspects of supporting people with SMI are often underprioritised in the health-care system. In a demanding and changing context, strategic multiagency working was seen as crucial but we found few examples of embedded multisector organisation partnerships. Conclusion While our exploratory study has limitations, findings suggest potential for people with SMI to be supported to become more active managers of their personal networks to support well-being regardless of current network type. The health and social care system does not currently deliver multiagency integrated solutions to support SMI and social recovery

The local environmental impact of prehistoric populations on Saibai Island, Northern Torres Strait - enigmatic evidence from Holocene swamp lithostratigraphic records

The mid- to late-Holocene palaeoenvironmental history of a low island adjacent to the southern Papuan coast is reconstructed from sedimentary and pollen analysis of swamp stratigraphies, supported by conventional and AMS radiocarbon dating, in an effort to constrain dates for prehistoric horticultural activity. Extensive prehistoric relict mound-and-ditch horticultural field systems located on low, flat clayland areas adjacent to the swamps appear to have been constructed after 2500 yr BP, but before 19th century European contact, based on archaeological and ethnographic evidence. Facies changes in swamp basin infill stratigraphy indicate conformable deposition within tidal lagoonal mangrove environments until c. 3000 yr BP. Then shallowing water conditions resulted in a transition to brackish-freshwater facies, and a vegetation change to sedge-dominated swamps. The observed shift from mangrove to sedge-dominated communities occurred during a falling trend in local relative sea level which may have initiated mangrove dieback. Onset of allocthonous deposition of clayland-derived sediments, related to horticulture on swamp-marginal clayland, significantly post-dates the mangrove to sedge community change in the pollen record. Close temporal coincidence of radiocarbon dates for human occupation and sandy facies deposition at swamp edges implies significant anthropic disturbance on the clayland around 1200 yr BP, but evidence for a process-link remains equivocal

Stone Constructions on Rankin Island, Kimberley, Western Australia

Here we report on a variety of stone constructions that have been recently recorded and mapped on Rankin Island in the Kimberley region of Western Australia. The function of one of these features, a long stone wall, is discussed in the context of simila