title: Radiocarbon dating of burials from the Teouma Lapita cemetery, Efate, Vanuatu

authors: Petchey, Fiona

subjects: Calibration

abstract: The discovery of a cemetery at Teouma on the island of Efate in Vanuatu dated to c. 3000 years ago increased the number of early Pacific human remains available for study by nearly an order of magnitude and provided for the first time the ability to study the population dynamics of these early colonizers. The cemetery also provided an opportunity to investigate the chronological development of such a unique site. Although identified short-lived plant materials are favoured for dating archaeological sites, the reality of research in the Pacific region is that such materials are often rare, difficult to identify to species because of an absence of suitable reference collections, and dates on other materials often have greater potential to refine and focus ¹⁴C chronologies that deal with specific research questions. At Teouma, dates on the burial remains themselves are the best means to answer questions about the age and duration of the burial ground. Human bone, however, is one of the most complicated materials to date reliably because of dietary ¹⁴C offsets and bone preservation. One commonly used methodology for calibrating dates on human bone from Pacific human skeletal remains, based on linear interpolation between δ¹³C endpoints and δ¹⁵N values, is complicated by the wide range of foods available (marine, reef, C₄ and C₃), and remains largely untested in Pacific contexts. Radiocarbon dating of the Teouma site, including 36 Lapita-age burials, 5 dates on Conus sp. ring artefacts, and dates from the associated midden deposit, has enabled further evaluation of ¹⁴C dietary offsets and the reliability of calibrated radiocarbon ages on human bone. Bayesian evaluation of the ¹⁴C dates suggests the burial ground was in regular use by c. 2940-2880 cal BP, with the last interments occurring c. 2770-2710 cal BP. A number of burials could indicate possible earlier use, perhaps as early as 3110-2930 cal BP as indicated by the calibrated age range of Burial 57. This cannot be independently substantiated using other radiocarbon dates or context at the present time. Overall, these results suggest the burial ground was in use over a possible 150 to 240 years during the formative phase of Lapita expansion into Remote Oceania.

text: Radiocarbon dating of burials from the Teouma Lapita cemetery, Efate, Vanuatu The discovery of a cemetery at Teouma on the island of Efate in Vanuatu dated to c. 3000 years ago increased the number of early Pacific human remains available for study by nearly an order of magnitude and provided for the first time the ability to study the population dynamics of these early colonizers. The cemetery also provided an opportunity to investigate the chronological development of such a unique site. Although identified short-lived plant materials are favoured for dating archaeological sites, the reality of research in the Pacific region is that such materials are often rare, difficult to identify to species because of an absence of suitable reference collections, and dates on other materials often have greater potential to refine and focus ¹⁴C chronologies that deal with specific research questions. At Teouma, dates on the burial remains themselves are the best means to answer questions about the age and duration of the burial ground. Human bone, however, is one of the most complicated materials to date reliably because of dietary ¹⁴C offsets and bone preservation. One commonly used methodology for calibrating dates on human bone from Pacific human skeletal remains, based on linear interpolation between δ¹³C endpoints and δ¹⁵N values, is complicated by the wide range of foods available (marine, reef, C₄ and C₃), and remains largely untested in Pacific contexts. Radiocarbon dating of the Teouma site, including 36 Lapita-age burials, 5 dates on Conus sp. ring artefacts, and dates from the associated midden deposit, has enabled further evaluation of ¹⁴C dietary offsets and the reliability of calibrated radiocarbon ages on human bone. Bayesian evaluation of the ¹⁴C dates suggests the burial ground was in regular use by c. 2940-2880 cal BP, with the last interments occurring c. 2770-2710 cal BP. A number of burials could indicate possible earlier use, perhaps as early as 3110-2930 cal BP as indicated by the calibrated age range of Burial 57. This cannot be independently substantiated using other radiocarbon dates or context at the present time. Overall, these results suggest the burial ground was in use over a possible 150 to 240 years during the formative phase of Lapita expansion into Remote Oceania.

year: 2014

title: Evolution of the global carbon cycle and climate regulation on Earth

authors: Isson, Terry T.

subjects: Carbon cycle

abstract: The existence of stabilizing feedbacks within Earth's climate system is generally thought to be necessary for the persistence of liquid water and life. Over the course of Earth's history, Earth's atmospheric composition appears to have adjusted to the gradual increase in solar luminosity, resulting in persistently habitable surface temperatures. With limited exceptions, the Earth system has been observed to recover rapidly from pulsed climatic perturbations. Carbon dioxide (CO₂) regulation via negative feedbacks within the coupled global carbon‐silica cycles are classically viewed as the main processes giving rise to climate stability on Earth. Here we review the long‐term global carbon cycle budget, and how the processes modulating Earth's climate system have evolved over time. Specifically, we focus on the relative roles that shifts in carbon sources and sinks have played in driving long‐term changes in atmospheric pCO₂. We make the case that marine processes are an important component of the canonical silicate weathering feedback, and have played a much more important role in 𝘱CO₂ regulation than traditionally imagined. Notably, geochemical evidence indicate that the weathering of marine sediments and off‐axis basalt alteration act as major carbon sinks. However, this sink was potentially dampened during Earth's early history when oceans had higher levels of dissolved silicon (Si), iron (Fe), and magnesium (Mg), and instead likely fostered more extensive carbon recycling within the ocean‐atmosphere system via reverse weathering—that in turn acted to elevate ocean‐atmosphere CO₂ levels.

text: Evolution of the global carbon cycle and climate regulation on Earth The existence of stabilizing feedbacks within Earth's climate system is generally thought to be necessary for the persistence of liquid water and life. Over the course of Earth's history, Earth's atmospheric composition appears to have adjusted to the gradual increase in solar luminosity, resulting in persistently habitable surface temperatures. With limited exceptions, the Earth system has been observed to recover rapidly from pulsed climatic perturbations. Carbon dioxide (CO₂) regulation via negative feedbacks within the coupled global carbon‐silica cycles are classically viewed as the main processes giving rise to climate stability on Earth. Here we review the long‐term global carbon cycle budget, and how the processes modulating Earth's climate system have evolved over time. Specifically, we focus on the relative roles that shifts in carbon sources and sinks have played in driving long‐term changes in atmospheric pCO₂. We make the case that marine processes are an important component of the canonical silicate weathering feedback, and have played a much more important role in 𝘱CO₂ regulation than traditionally imagined. Notably, geochemical evidence indicate that the weathering of marine sediments and off‐axis basalt alteration act as major carbon sinks. However, this sink was potentially dampened during Earth's early history when oceans had higher levels of dissolved silicon (Si), iron (Fe), and magnesium (Mg), and instead likely fostered more extensive carbon recycling within the ocean‐atmosphere system via reverse weathering—that in turn acted to elevate ocean‐atmosphere CO₂ levels.

year: 2020

title: Editorial

authors: Clarkin-Phillips, Jeanette

abstract: As New Zealand contemplates wholesale review of the formal schooling system and the leadership implications thereof, the winds of educational change begin to swirl. Not the persistent, yet gentle flutter of change that evolves the educational landscape in almost imperceptible ways, but tumultuous paradigmatic gales that potentially change it beyond all recognition. Heralded by politicians, economists and capitalists, there is little doubt that the 1989 neoliberal tempest wrought havoc on notions of community and profession. The whirlwind shift from social democracy to market competition, managerialism and performativity saw critical voices silenced and educators disparagingly positioned as self-interested providers. In the rush to legislate Tomorrow’s Schools, 18,000 submissions remained unanalysed and therein lies a crucial lesson: we ignore research at our peril. As educators, we have a moral obligation to generate, disseminate and critique understandings of leadership, policy and practice; to remain open to counter perspectives; and to contribute positively and hopefully to research that empowers and emancipates. Consistent with JELPP’s commitment to honouring diversity in leadership focus, setting, and authorship, articles in this year’s general edition offer fresh insight into topics of interconnected and perennial importance: native knowledge, instructional leadership, indigenous teachers, appraisal, professional values, and safe schools.

text: Editorial As New Zealand contemplates wholesale review of the formal schooling system and the leadership implications thereof, the winds of educational change begin to swirl. Not the persistent, yet gentle flutter of change that evolves the educational landscape in almost imperceptible ways, but tumultuous paradigmatic gales that potentially change it beyond all recognition. Heralded by politicians, economists and capitalists, there is little doubt that the 1989 neoliberal tempest wrought havoc on notions of community and profession. The whirlwind shift from social democracy to market competition, managerialism and performativity saw critical voices silenced and educators disparagingly positioned as self-interested providers. In the rush to legislate Tomorrow’s Schools, 18,000 submissions remained unanalysed and therein lies a crucial lesson: we ignore research at our peril. As educators, we have a moral obligation to generate, disseminate and critique understandings of leadership, policy and practice; to remain open to counter perspectives; and to contribute positively and hopefully to research that empowers and emancipates. Consistent with JELPP’s commitment to honouring diversity in leadership focus, setting, and authorship, articles in this year’s general edition offer fresh insight into topics of interconnected and perennial importance: native knowledge, instructional leadership, indigenous teachers, appraisal, professional values, and safe schools.

year: 2019