6 results for Almond, Peter C.

  • Quaternary research in New Zealand since 2000: an overview

    Bostock, Helen C.; Lowe, David J.; Newnham, Rewi M.; Almond, Peter C. (2012)

    Journal article
    University of Waikato

    With the AQUA milestone of 30 years it seems an appropriate time to review the progress and achievements of Quaternary research in New Zealand. This article highlights some of the major achievements since the formal review of New Zealand’s Quaternary record by Newnham et al. (1999). The focus here is on paleoclimate and geochronology and is by no means a comprehensive review. We encourage members to write future articles for Quaternary Australasia (QA) about their exciting projects to keep the wider Australasian community informed. One of the main differences between Australian and New Zealand Quaternary science is the wide use of tephrochronology to correlate and date deposits and events across the landscape, helping to link terrestrial and marine records, especially in the North Island. There have been significant advances using glass-based fission-track dating, corrected for annealing, and the use of the electron microprobe and laser ablation inductively-coupled plasma mass spectrometry for obtaining major- and trace-element analyses, respectively, to chemically fingerprint individual glass shards in tephras to aid their correlation (Shane, 2000; Lowe, 2011). Also the identification and analysis of cryptotephras (concentrations of glass shards not visible as a layer) have greatly expanded the geographic range of many tephras, allowing the application of tephrochronology as a stratigraphic and dating tool across much wider areas than previously possible (Gehrels et al., 2008).

    View record details
  • Towards a climate event stratigraphy for New Zealand over the past 30,000 years (NZ-INTIMATE project)

    Alloway, Brent V.; Lowe, David J.; Barrell, David J.A.; Newnham, Rewi M.; Almond, Peter C.; Augustinus, Paul Christian; Bertler, Nancy A.N.; Carter, Lionel; Litchfield, Nicola J.; McGlone, Matt S.; Shulmeister, Jamie; Vandergoes, Marcus J.; Williams, Paul W.; NZ-INTIMATE members (2007-01)

    Journal article
    University of Waikato

    It is widely recognised that the acquisition of high-resolution palaeoclimate records from southern mid-latitude sites is essential for establishing a coherent picture of inter-hemispheric climate change and for better understanding of the role of Antarctic climate dynamics in the global climate system. New Zealand is considered to be a sensitive monitor of climate change because it is one of a few sizeable landmasses in the Southern Hemisphere westerly circulation zone, a critical transition zone between subtropical and Antarctic influences. New Zealand has mountainous axial ranges that amplify the climate signals and, consequently, the environmental gradients are highly sensitive to subtle changes in atmospheric and oceanic conditions. Since 1995, INTIMATE has, through a series of international workshops, sought ways to improve procedures for establishing the precise ages of climate events, and to correlate them with high precision, for the last 30 000 calendar years. The NZ-INTIMATE project commenced in late 2003, and has involved virtually the entire New Zealand palaeoclimate community. Its aim is to develop an event stratigraphy for the New Zealand region over the past 30 000 years, and to reconcile these events against the established climatostratigraphy of the last glacial cycle which has largely been developed from Northern Hemisphere records (e.g. Last Glacial Maximum (LGM), Termination I, Younger Dryas). An initial outcome of NZ-INTIMATE has been the identification of a series of well-dated, high-resolution onshore and offshore proxy records from a variety of latitudes and elevations on a common calendar timescale from 30 000 cal. yr BP to the present day. High-resolution records for the last glacial coldest period (LGCP) (including the LGM sensu stricto) and last glacial-interglacial transition (LGIT) from Auckland maars, Kaipo and Otamangakau wetlands on eastern and central North Island, marine core MD97-2121 east of southern North Island, speleothems on northwest South Island, Okarito wetland on southwestern South Island, are presented. Discontinuous (fragmentary) records comprising compilations of glacial sequences, fluvial sequences, loess accumulation, and aeolian quartz accumulation in an andesitic terrain are described. Comparisons with ice-core records from Antarctica (EPICA Dome C) and Greenland (GISP2) are discussed. A major advantage immediately evident from these records apart from the speleothem record, is that they are linked precisely by one or more tephra layers. Based on these New Zealand terrestrial and marine records, a reasonably coherent, regionally applicable, sequence of climatically linked stratigraphic events over the past 30 000 cal. yr is emerging. Three major climate events are recognised: (1) LGCP beginning at ca. 28 000 cal. yr BP, ending at Termination I, ca. 18 000 cal. yr BP, and including a warmer and more variable phase between ca. 27 000 and 21 000 cal. yr BP, (2) LGIT between ca. 18 000 and 11 600 cal. yr BP, including a Lateglacial warm period from ca. 14 800 to 13 500 cal. yr BP and a Lateglacial climate reversal between ca. 13 500 and 11 600 cal. yr BP, and (3) Holocene interglacial conditions, with two phases of greatest warmth between ca. 11 600 and 10 800 cal. yr BP and from ca. 6 800 to 6 500 cal. yr BP. Some key boundaries coincide with volcanic tephras.

    View record details
  • Geology, landforms and soils of the Waipara and Waikari regions of North Canterbury with an emphasis on lands used for viticulture

    Tonkin, P.; Webb, T.; Almond, Peter C.; Creasy, Glen; Harrison, Roland; Hassall, Leanne J.; Smith, Carol

    Book
    Lincoln University

    Soils play an important role in grape growing and wine making. Soils anchor the vine and act a reservoir of water and nutrients essential for growth. Soils influence the vine microclimate and therefore wine characteristics. ... This report is organized into 16 chapters, and these can be grouped into three part. The first part includes this introduction, and chapters on geological history, landform history and and overview of the soils within the the Waipara and Waikari regions of North Canterbury. This last chapter includes a summary table listing the landforms, regolith, soil and their New Zealand Soil Classification and maps of the landforms and dominant soil series associated with wine growing in North Canterbury. The second part of the report is ordered using the landform relationships of the predominant soils established in the previous section. This is referred to as a physiographic order from the highest and steepest parts of the landscape to the youngest surfaces alongside streams and rivers and on recently active fans. There are eight sections in this part and all available information on the soils’ morphology (description) and chemistry are included in this section up to the time of completion of this report. The third part of the report includes three chapters. The first section is a discussion of soil mapping and the definition of terms associated with soil mapping. These include field identification of soil profiles and soil profile description and the definition of soil horizon notation used in this report and field determination of soil texture, consistence and structure. A simple field method for determining the presence of primary and secondary calcium carbonate using a dilute acid is described. This chapter concludes with the New Zealand Soil Classification (Hewitt, 2010) relevant to the soils of North Canterbury described in this report. The next chapter is a discussion on the interpretation of soil chemistry data. The final chapter in this section comprises tables listing the vineyards of the Waipara and Waikari regions of North Canterbury grouped by the dominant soil or combinations of soils within vineyards. The location of Waipara vineyards are plotted on three maps, of the Omihi Valley, north of the Waipara River and the southern part of the Omihi valley, and south of the Waipara River. This information was last updated in January 2014.

    View record details
  • Test of AMS 14C dating of pollen concentrates using tephrochronology

    Newnham, Rewi M.; Vandergoes, Marcus J.; Garnett, Mark H.; Lowe, David J.; Prior, Christine; Almond, Peter C. (2007-01)

    Journal article
    University of Waikato

    Previous attempts to radiocarbon date sediments >10 kyr from the high rainfall region of Westland, New Zealand, a critical location for investigation of interhemispheric patterns of climate change, have been problematic. This study, building on recent work by Vandergoes and Prior (2003), shows that AMS 14C dating of pollen concentrates has potential to provide more reliable ages than other sediment constituents, including plant macrofossils. The method was applied to sediments from three sites containing the 22.6k 14C yr Kawakawa Tephra, which provided an independent test of the 14C ages. Although some minor laboratory contamination was detected in tests on background standards, the modelled relationship between sample mass and measured 14C content permitted an appropriate correction to be determined. Improved pollen concentrations derived by density separation between 1.4 and 1.2 specific gravity and sieving in the range 10-50 m provided either older ages than other fractions of the same sample or, where in situ contamination was not evident, equivalent ages. Differences in degree of in situ contamination between depositional environments indicated that, in Westland, lake sites may be less susceptible to contamination by younger carbon than peat sites, where this process may be facilitated by root penetration into underlying sediments.

    View record details
  • A composite pollen-based stratotype for inter-regional evaluation of climatic events in New Zealand over the past 30,000 years (NZ-INTIMATE project)

    Barrell, David J.A.; Almond, Peter C.; Vandergoes, Marcus J.; Lowe, David J.; Newnham, Rewi M.; INTIMATE members 12 (2013)

    Journal article
    University of Waikato

    Our review of paleoclimate information for New Zealand pertaining to the past 30,000 years has identified a general sequence of climatic events, spanning the onset of cold conditions marking the final phase of the Last Glaciation, through to the emergence to full interglacial conditions in the early Holocene. In order to facilitate more detailed assessments of climate variability and any leads or lags in the timing of climate changes across the region, a composite stratotype is proposed for New Zealand. The stratotype is based on terrestrial stratigraphic records and is intended to provide a standard reference for the intercomparison and evaluation of climate proxy records. We nominate a specific stratigraphic type record for each climatic event, using either natural exposure or drill core stratigraphic sections. Type records were selected on the basis of having very good numerical age control and a clear proxy record. In all cases the main proxy of the type record is subfossil pollen. The type record for the period from ca 30 to ca 18 calendar kiloyears BP (cal. ka BP) is designated in lake-bed sediments from a small morainic kettle lake (Galway tarn) in western South Island. The Galway tarn type record spans a period of full glacial conditions (Last Glacial Coldest Period, LGCP) within the Otira Glaciation, and includes three cold stadials separated by two cool interstadials. The type record for the emergence from glacial conditions following the termination of the Last Glaciation (post-Termination amelioration) is in a core of lake sediments from a maar (Pukaki volcanic crater) in Auckland, northern North Island, and spans from ca 18 to 15.64 ± 0.41 cal. ka BP. The type record for the Lateglacial period is an exposure of interbedded peat and mud at montane Kaipo bog, eastern North Island. In this high-resolution type record, an initial mild period was succeeded at 13.74 ± 0.13 cal. ka BP by a cooler period, which after 12.55 ± 0.14 cal. ka BP gave way to a progressive ascent to full interglacial conditions that were achieved by 11.88 ± 0.18 cal. ka BP. Although a type section is not formally designated for the Holocene Interglacial (11.88 ± 0.18 cal. ka BP to the present day), the sedimentary record of Lake Maratoto on the Waikato lowlands, northwestern North Island, is identified as a prospective type section pending the integration and updating of existing stratigraphic and proxy datasets, and age models. The type records are interconnected by one or more dated tephra layers, the ages of which are derived from Bayesian depositional modelling and OxCal-based calibrations using the IntCal09 dataset. Along with the type sections and the Lake Maratoto record, important, well-dated terrestrial reference records are provided for each climate event. Climate proxies from these reference records include pollen flora, stable isotopes from speleothems, beetle and chironomid fauna, and glacier moraines. The regional composite stratotype provides a benchmark against which to compare other records and proxies. Based on the composite stratotype, we provide an updated climate event stratigraphic classification for the New Zealand region. The stratotype and event classification are not intended to act as definitive statements of paleoclimate history for the New Zealand region, but rather provide a firm baseline against which to compare other records including those from the marine realm.

    View record details
  • A revised age for the Kawakawa/Oruanui tephra, a key marker for the Last Glacial Maximum in New Zealand

    Vandergoes, Marcus J.; Hogg, Alan G.; Lowe, David J.; Newnham, Rewi M.; Denton, George H.; Southon, John R.; Barrell, David J.A.; Wilson, Colin J.N.; McGlone, Matt S.; Allan, Aidan S.R.; Almond, Peter C.; Petchey, Fiona; Dabell, Kathleen; Dieffenbacher-Krall, Ann C.; Blaauw, Maarten (2013)

    Journal article
    University of Waikato

    The Kawakawa/Oruanui tephra (KOT) is a key chronostratigraphic marker in terrestrial and marine deposits of the New Zealand (NZ) sector of the southwest Pacific. Erupted early during the Last Glacial Maximum (LGM), the wide distribution of the KOT enables inter-regional alignment of proxy records and facilitates comparison between NZ climatic variations and those from well-dated records elsewhere. We present 22 new radiocarbon ages for the KOT from sites and materials considered optimal for dating, and apply Bayesian statistical methods via OxCal4.1.7 that incorporate stratigraphic information to develop a new age probability model for KOT. The revised calibrated age, ±2 standard deviations, for the eruption of the KOT is 25,360 ± 160 cal yr BP. The age revision provides a basis for refining marine reservoir ages for the LGM in the southwest Pacific.

    View record details