A Very Quaternary Week in Auckland

With only a 36 hour turnaround after our trip to Corner County, I was back at Sydney airport. This time, I was boarding slightly larger plane bound for Auckland, New Zealand, for the biennial meeting of the Australasian Quaternary Association (AQUA). Whilst I’ve been to the massive congresses of the International Union for Quaternary Research (INQUA) before, this promised to be a smaller, friendly meeting, focusing mainly on the Quaternary (the last ~2 million years) research being undertaken in Australian and New Zealand.

I was not disappointed – with probably just over a hundred participants at a range of career stages, the presentations covered topics from glaciers to deserts, oceans to climate change, and a exciting range of new techniques for unravelling climate in the past.My poster outlining SURFACE also provoked some interesting discussions about landscape archaeology in arid areas in Australia.

As well as the scientific discussion in the lecture hall, there was a field trip which gave us a whiz around some of the North Island’s Quaternary highlights. Auckland sits on top of a volcanic field, with numerous cinder cones covered in grass poking up through the suburbs – a big departure from the bare cinder cones I’m familiar with in Saudi, even though they were formed the same way! Our first stop was at one of these cones, Mt Eden. Erupting 20-30,000 years ago, its flanks were shaped for cultivation and occupation by Maori, and later European, settlers. We took in panoramic views over the city to situate ourselves within the volcanic field, with the youngest, and only shield, volcano, Rangitoto, sitting just off the coast.

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A view from Mt Eden across the Auckland suburbs to Rangitoto shield volcano. Photo: R. Inglis.

Onwards to Cascades Kauri Park NP where we were on the hunt for Kauri trees – these beautiful, gigantic trees are hundreds of years old, and hold an amazing archive of past climates in their growth rings, and so are a special area of focus for researchers at NIWA (the conference organisers). By counting the rings, and comparing their varying widths to sequences in other Kauri trees, researchers can build up a long reference sequence – a dendrochronology – that samples from timbers in houses, wooden artefacts etc. can be compared to to work out when the trees were felled, and thus a maximum age for the timber.

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The temperate rainforest of the Cascades Kauri NP. Photo: R. Inglis.

The rings themselves also contain the potential to inform on past climates. Because the chronology of the rings is so tight, measuring the isotopic properties of the wood from each of these rings can tell researchers about changes in climate with a yearly resolution. This is excellent for tracing the impact of regional and wider climatic cycles, such as the impact of the El Niño–Southern Oscillation over recent centuries, a record that will allow us to understand how ENSO changes in the face of climate change could affect the region in future. As well as all this, the Kauri record also contains a yearly record of Carbon 14 concentrations, essential for calibrating radiocarbon dating.

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A Kauri tree – a cornucopia of dating and palaeoclimatic records. Photo: R. Inglis.

Our final stop of the day was at Lake Pupuke, a giant crater, or maar, formed by a volcanic eruption, and infilled with water to form a lake. Whilst the weather was decidedly gloomy by the time we’d reached it, the lake itself holds an exciting sequence of sediments that are being studied by researchers at the University of Auckland, lead by Paul Augustinus, to unravel the volcanic and climatic history of the region, through the volcanic and lake deposits preserved within them. They are up to 70,000 years of sediment and counting…

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Don’t let the weather put you off – Lake Pupuke holds an amazing sequence of sediments and volcanic deposits. Photo: R. Inglis.

Thanks to all the organisers for a great conference, with many stimulating talks, some lovely socials and an excellent field trip – Merry Christmas to all!

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