Coastal landscape evolution

ARC grant supports study in Southern Australia

Researchers will use innovative modelling techniques to document and date the nature and implications of the historic environmental changes that shaped Australia’s modern coastal landscapes thanks to a $391,000 Australian Research Council Discovery Project grant.

The project, Global climate change and coastal landscape evolution in southern Australia, will focus on the Coorong Coastal Plain, a natural laboratory for geologists like Professor Colin Murray-Wallace, one of the research team’s Chief Investigators from UOW.

“This project aims to reconstruct environmental changes that occurred in southern Australia during and after a geologically recent time interval termed the Early-Middle Pleistocene Transition and an interglacial period some 400,000 years ago,” Professor Murray-Wallace said.

The Early-Middle Pleistocene Transition was 1.2 million to 700 thousand years ago and has been described by experts as one of the most striking geological events during the past 50 million years.

“The Transition involved a global reorganisation of climate states and represents the most significant climate change event during the Quaternary Period – the past 2.59 million years,” Professor Murray-Wallace explained.

“The sequence of inferred climate changes that occurred during the EMPT has been well-defined in longer-term marine-based oxygen isotope records. However, little is known about how these changes were manifested in coastal and terrestrial environments.

“This project seeks to address this imbalance by examining sedimentary successions from coastal barriers of the Coorong Coastal Plain – Murray Basin and a coastal alluvial fan complex bounding the Southern Mt Lofty Ranges in southern Australia.”

The Coorong Coastal Plain – Murray Basin region is a unique part of the world that, according to Professor Murray-Wallace, provides the most significant location on Earth to examine the geomorphological expression of the Early-Middle Pleistocene Transition (EMPT) in terms of coastal barrier landform evolution.

“These contrasting landscapes have been selected for their sensitivity to environmental and climatic changes, and the complementary records they will both provide about the nuances of coastal landscape evolution in a critical part of the Quaternary record in the southern hemisphere.”

Those involved in the research have substantial experience in the development and application of the geochronological, geochemical and modelling techniques to be used in the project to examine the environmental changes in the area.

“We have assembled a team that is able to synthesise the analytical results from the two field regions and derive a conceptual model of long-term landscape change in response to profound global climate and environmental changes,” Professor Murray-Wallace said.

The team includes Chief Investigators Dr Nicolas Flament from UOW, Professor Bradley Pillans from Australian National University, Associate Professor Paul Hesse from Macquarie University and Professor Mark Bateman, a partner investigator, from the University of Sheffield, UK.

Research impact

The information derived from the research will have a significant and wide-ranging impact beyond helping researchers understand the fundamental changes that occurred during the EMPT and how these changes were manifested in other landscape systems.

From an international perspective, the project will fill a significant gap in knowledge about how modern coastal landscapes have responded and developed during a period of profound global climate-change, initiated with the increasing amplitude of global ice-volume and sea-level changes accompanying fluctuations in the northern hemisphere ice sheets.

The derived geological information will also refine the understanding of coastal environmental processes, sea-level changes and global climate-changes as they relate to fisheries, construction and engineering industries and potential geohazards.

Closer to home, the research findings will also assist in the management of landscapes in the Lower Murray-Darling drainage system, a critical issue for Australia. In economic terms, the research will assist in reducing the costs of land management by identifying the key drivers of landscape change and their impact on human land use.

In a cultural and social heritage context, the research will enhance the understanding of the inherent nature of Australian landscapes and their perceived influence on national identity, as well as providing important geological information of commercial significance in geotourism.

Socially, it will enhance the understanding of the role of climate-change in landscape development and the sensitivity of landscape response to climate change, particularly concerning a time-frame for the intensification of regional aridity in southern Australia.

COLIN MURRAY-WALLACE: To find out more about Colin Murray-Wallace take a look at his scholars profile