The University of Southampton
University of Southampton Institutional Repository

Static or dynamic: reconstructing past movement of the South Pacific Convergence Zone

Static or dynamic: reconstructing past movement of the South Pacific Convergence Zone
Static or dynamic: reconstructing past movement of the South Pacific Convergence Zone
The largest climate system in the world exists over the Pacific Ocean. The behaviour of this system, which comprises El Nino/La Nina events and the South Pacific Convergence Zone (SPCZ), influences climate across the globe. Despite its importance, and because the region comprises archipelagos of sparsely populated islands, our understanding of the movement of the SPCZ is limited over the Holocene. This study addresses the lack of long, continuous records from this region to reconstruct movement of the SPCZ over millennial timescales.

Using a variety of geochemical proxies (compound-specific δ13C and δ2H analyses on nalkanoic acids, total organic carbon δ13C, C/N, Itrax and magnetic susceptibility) from two sites (Lake Teroto, Atiu, Cook Islands, and Lake Lanoto’o, Samoa) this study has developed two palaeoclimatic reconstructions from which clear changes in SPCZ movement have been identified. A clear expansion and/or migration southeast is determined in the mid-Holocene (ca. 5,600-2,700 cal yr BP). Using the known relationship between SPCZ movement and prevailing climate states in the Pacific, specifically ENSO and IPO, inferences have been made on changes in these climate phenomena over the Holocene. When using a network of ENSO records from the tropical Pacific it is apparent that there are three distinct periods where a flavour of El Niño dominates: an early Holocene (ca. 9,500-6,800 cal yr BP) dominated by east Pacific El Niños; a transition period from ca. 6,800-5,600 cal yr BP before central Pacific El Niños dominate from ca. 5,600-2,700 cal yr BP; and a dominance of east Pacific El Niños from 2,700 cal yr BP to present. The first evidence for the 8.2 ka event is presented from the southwest tropical Pacific.
University of Southampton
Hassall, Jonathan David
17b719cf-5b7b-496a-8bf7-96c57618baca
Hassall, Jonathan David
17b719cf-5b7b-496a-8bf7-96c57618baca
Sear, David
ccd892ab-a93d-4073-a11c-b8bca42ecfd3
Langdon, Peter
95b97671-f9fe-4884-aca6-9aa3cd1a6d7f
Croudace, Ian
24deb068-d096-485e-8a23-a32b7a68afaf

Hassall, Jonathan David (2017) Static or dynamic: reconstructing past movement of the South Pacific Convergence Zone. University of Southampton, Doctoral Thesis, 374pp.

Record type: Thesis (Doctoral)

Abstract

The largest climate system in the world exists over the Pacific Ocean. The behaviour of this system, which comprises El Nino/La Nina events and the South Pacific Convergence Zone (SPCZ), influences climate across the globe. Despite its importance, and because the region comprises archipelagos of sparsely populated islands, our understanding of the movement of the SPCZ is limited over the Holocene. This study addresses the lack of long, continuous records from this region to reconstruct movement of the SPCZ over millennial timescales.

Using a variety of geochemical proxies (compound-specific δ13C and δ2H analyses on nalkanoic acids, total organic carbon δ13C, C/N, Itrax and magnetic susceptibility) from two sites (Lake Teroto, Atiu, Cook Islands, and Lake Lanoto’o, Samoa) this study has developed two palaeoclimatic reconstructions from which clear changes in SPCZ movement have been identified. A clear expansion and/or migration southeast is determined in the mid-Holocene (ca. 5,600-2,700 cal yr BP). Using the known relationship between SPCZ movement and prevailing climate states in the Pacific, specifically ENSO and IPO, inferences have been made on changes in these climate phenomena over the Holocene. When using a network of ENSO records from the tropical Pacific it is apparent that there are three distinct periods where a flavour of El Niño dominates: an early Holocene (ca. 9,500-6,800 cal yr BP) dominated by east Pacific El Niños; a transition period from ca. 6,800-5,600 cal yr BP before central Pacific El Niños dominate from ca. 5,600-2,700 cal yr BP; and a dominance of east Pacific El Niños from 2,700 cal yr BP to present. The first evidence for the 8.2 ka event is presented from the southwest tropical Pacific.

Text
Static or dynamic: reconstructing past movement of the South Pacific Convergence Zone - Version of Record
Available under License University of Southampton Thesis Licence.
Download (23MB)

More information

Published date: April 2017

Identifiers

Local EPrints ID: 415345
URI: http://eprints.soton.ac.uk/id/eprint/415345
PURE UUID: a7b9bac3-dfd8-481b-9971-8ae5e8d15c04
ORCID for David Sear: ORCID iD orcid.org/0000-0003-0191-6179
ORCID for Peter Langdon: ORCID iD orcid.org/0000-0003-2724-2643

Catalogue record

Date deposited: 07 Nov 2017 17:30
Last modified: 14 Mar 2019 01:52

Export record

Contributors

Author: Jonathan David Hassall
Thesis advisor: David Sear ORCID iD
Thesis advisor: Peter Langdon ORCID iD
Thesis advisor: Ian Croudace

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×