University of Waikato Radiocarbon Dates I

Abstract

The radiocarbon dating laboratory at Waikato was established in 1975, primarily as a research tool in the fields of geomorphology, volcanology, tephrostratigraphy, coastal studies, and paleolimnology, to cope with the increasing supply of late Quaternary lake sediment, wood, peat, and shell samples submitted by University staff and postgraduate students undertaking research in the North Island of New Zealand. The method employed is scintillation counting of benzene using the procedures and vacuum systems designed by H A Polach for the Australian National University (ANU) Radiocarbon Dating Research Laboratory (Hogg, 1982). This date list reports on samples submitted by University of Waikato researchers and assayed in the Waikato laboratory mainly between 1979 and 1985. Other dates on material submitted by individuals working in other organizations in New Zealand, and overseas, are to be reported later.

Stratigraphy, age, composition, and correlation of late Quaternary tephras interbedded with organic sediments in Waikato lakes, North Island, New Zealand

“…(1980) for Lake Maratoto were partly modified (some tephras were re-identified) and further cores examined in more detail by Green & Lowe (1985). Some analyses of cores from other Waikato lakes have been reported by Lowe et al (1981), Lowe (1986a, b), and Hogg et at. (1987).…”

Stratigraphy and chronology of a 15 ka sequence of multi‐sourced silicic tephras in a montane peat bog, eastern North Island, New Zealand

“…Although no direct dates are available for this tephra near its source, it is constrained chronostratigraphically by Karapiti and Waiohau Tephras to between c. 10 000 and 11 850 I4 C yr BP (Donoghue et al 1995b(Donoghue et al , 1999. Its likely distal correlative in the Waikato region, "Okupata-1", was assigned an age of c. 10 100 I4 C yr BP based on a series of dates on stratigraphically adjacent deposits in Lake Maratoto (Hogg et al 1987;Lowe 1988b). These dates included 10 000 + 120 I4 CyrBP(Wk232)and 10 120±100 14 CyrBP(Wk213) from tephras just above "Okupata-1", and 10 100 ± 100 14 C yr BP (Wk519) on "Egmont-11" (i.e., Konini Tephra) just below it (Lowe 1988b).…”

“…Thirty-four radiocarbon dates, 20 on peats ind 14 mean ages associated with the tephra layers, have been applied to the Kaipo sequence. These 14 tephra-based dates are derived, in turn, from some 250 radiocarbon dates on the tephras in environments elsewhere (e.g., Hogg et al 1987;Froggatt & Lowe 1990;Wilson 1993), that is, around 270 dates have, in effect, been brought to bear on the Kaipo sequence. The 34 radiocarbon dates applied to the sequence represent an average of one date every c. 80 mm of sediment (excluding tephra deposits), equivalent to c. 430 yr of sedimentation.…”

Vegetation recovery following fire in two Waikato peatlands at Whangamarino and Moanatuatua, New Zealand

“…The earliest peat at Moanatuatua has been dated at 13 300 + 110 yr BP (Hogg et al 1987), and peat accumulation reached a peak by 1939, when the dome was some 15 m above the southem margin of the bog (Taylor & Grange 1939). However, widespread drainage and conversion to farmland since then have resulted in peat shrinkage and lowering of the water table, which continue to affect the bog remnant.…”