ORCID Profile
0000-0002-7824-1184
Current Organisation
The University of Auckland
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Publisher: Springer Science and Business Media LLC
Date: 05-09-2012
Publisher: Elsevier BV
Date: 04-2011
Publisher: Elsevier BV
Date: 10-2012
Publisher: Frontiers Media SA
Date: 22-06-2017
Publisher: Society for Sedimentary Geology
Date: 31-10-2021
DOI: 10.2110/JSR.2020.021
Abstract: Lake sediment archives from Southern Hemisphere mid-latitude regions provide invaluable records of late Quaternary environmental change. Here, changes in depositional environment over the past ca. 53,000 years were reconstructed using a range of physical, sedimentological, geochemical, and μ-XRF elemental proxy datasets analyzed from lake sediment cores obtained from Lake Kanono, Northland, New Zealand. The Lake Kanono stratigraphy displays a terrestrial peat environment (ca. 53,700–6,670 cal yr BP), followed by a trend of increased influx of detrital sediment during the Late Glacial–Interglacial Transition (LGIT) at ca. 14,000 cal yr BP with a peak from ca. 12,000 to 9,000 cal yr BP driven by increasingly dry conditions. The increase in sediment influx continued during the early to mid-Holocene, leading to dune reactivation which altered the catchment dynamics of the region, leading to the inception of a shallow lake basin at ca. 6,670 cal yr BP. The timing of the formation of this lake basin can be associated with changes in intensity of the Southern Westerly Winds (SWW) and the appearance and increase in intensity of the El Niño Southern Oscillation (ENSO) after ca. 7,500–7,000 cal yr BP (Moy et al. 2002 Moreno et al. 2018). Drier conditions peaked from ca. 4,000 to 2,400 cal yr BP, possibly culminating in decreased lake levels that persisted from ca. 2,400 to 2,210 cal yr BP, renewed dune accumulation, and blocked stream outlets, resulting in a deep lake basin with thermal stratification that persisted to the present. Cluster analysis of the μ-XRF data demonstrates that the most prominent change in chemistry is near the onset of the Last Glacial Maximum (LGM) at ca. 26,700 cal yr BP associated with a transition to a drier, windier climate. The second most prominent change in the μ-XRF data is during the Polynesian phase of human settlement at ca. 612–575 cal yr BP (1338– 1375 CE). Hence, we can demonstrate the utility and power of a multi-proxy approach coupled with μ-XRF element data to interpret changing sediment sources to a lake basin. Such an approach allows rapid and reliable evaluation of catchment processes influenced by climate events and land-use changes at a resolution not available using other approaches.
Publisher: Cambridge University Press (CUP)
Date: 05-1998
Abstract: Sea-rafted Loisels Pumice is one of the few stratigraphic markers used to correlate late Holocene coastal deposits in New Zealand. Along with underlying sea-rafted products of the local Taupo eruption of ca. 1800 yr B.P., these events have been used to bracket the first arrival of humans at New Zealand. Loisels Pumice is dacitic to rhyolitic (SiO 2 63–78 wt%) in composition, but in idual clasts are homogeneous (SiO 2 range ± 1 wt%). Characteristics include very low K 2 O (0.5–1.75 wt%) and Rb ( ppm) and a mineralogy dominated by calcic and mafic xenocrysts. Similar features are shared by pumices of the Tonga–Kermadec arc, suggesting a common tholeiitic oceanic source. Interclast ersity of Loisels Pumice suggests that it is the product of several eruptive events from different volcanoes. The differences in glass and mineral compositions found at various sites can be explained if the deposits are from different events. A multisource origin can also partially explain the discrepancy in reported 14 C ages (ca. 1500–600 yr B.P.) from different localities. Therefore, the value of Loisels Pumice as a stratigraphic marker is questionable, and it does not constrain the arrival of humans. The predominant westward drift of historic Tonga–Kermadec arc pumices and prevailing ocean currents suggest a long anticlockwise semicircular transport route into the Tasman Sea before sea-rafted pumice arrival in New Zealand. The ersity of the pumices indicates that silicic eruptions frequently occur from the predominantly basic oceanic volcanoes.
Publisher: American Geophysical Union (AGU)
Date: 04-2010
DOI: 10.1029/2009GC002705
Publisher: Informa UK Limited
Date: 06-1998
Publisher: Elsevier BV
Date: 12-2001
Publisher: Informa UK Limited
Date: 09-2002
No related grants have been discovered for Philip Shane.