• Skip to main content
  • Skip to site footer
img MENU MEMBERSHIP img
  • Home
  • Donate
  • Join
  • Login
img
  • About Us
    • Mission
    • History
    • Values
    • Advocacy
    • Partners
    • People
  • Get Involved
    • What You Can Do
    • State Chapters
    • Become a Member
    • Donate
  • Resources
    • Photo Gallery
    • Conferences
    • Courses
  • Latest News
    • 2023
    • 2022
    • 2021
    • 2020
    • 2019
    • 2018
  • Blog
    • 2023
    • 2022
    • 2021
    • 2020
    • 2019
    • 2018
  • Podcast
  • Contact Us
Australian Coastal Society

Australian Coastal Society

We are the voice of the Australian coast

Neogene and Coasts

September 6, 2015
Main Image

Neogene and Coasts

Main Image

How Australia dried out and how our beaches were formed (photo source: australasianscience.com.au)

I have been reading this week some literature on the Neogene Period and coastal morphology. Why you may ask? Well for many years this geological period has underpinned much of what I have been thinking and writing about and in the course of this work have been fascinated by contrasting  evolution of coastal regions over a longer time period than we mostly think about.

First, let us define the Neogene. It is generally accepted (but not universally) that this period started around 23 million years ago and ended around 2.5 million years ago when we entered the Quaternary Period. It can be divided into two epochs: Miocene and Pliocene. It is an exciting part of geologic history (what part isn’t?) as we see continents more or less in their present positions, biota evolving into modern forms, and hominids appearing in Africa. From a climate  perspective we see the Earth cooling, large areas drying, glacial systems growing and thus sea levels falling.

I first encountered the Neogene in drilling holes in the Outer Coastal Plain of South Carolina in the 1960s. I spent two fascinating summers with a team from the South Carolina Geological Survey.  Quite frequently we encountered the fossil rich Duplin Formation as ‘’basement’’ in our drilling of Quaternary sediments. The Duplin is late Miocene to Pliocene in age. It represents a stand of the sea that stretches up to 100 km inland reaching 60-70 m high then dipping below sea level at the coast. Various sedimentary facies are represented. What is important is that it abuts on the landward side the Orangeburg Scarp, a feature that is interpreted along the coastal plain as a Neogene shoreline cut into older rocks of the Middle Coastal Plain. My work aimed to unravel the morphostratigraphy of materials that overlay the Neogene sediments. This involved mapping a series of sand barriers, backbarriers and fluvial surfaces of various ages noting that the barriers  occur at successively lower elevations towards the coast. It should be noted that along the Atlantic Coastal Plain the elevation of these surfaces of a given age varies including  the Orangeburg Scarp; they generally rise northwards indicating a degree of tectonic deformation.

Around sections of the Australian coast, especially the south and the southwest, a similar “staircase” sequence of shoreline deposits occurs stretching back into the Neogene; a good example is the calcarenite sequence in the lower Murray-Darling Basin. However, things are different along the east coast north from Gippsland Basin. The highest marine shoreline deposits are of late Quaternary age reaching no more than around 5-10m elevation. Marine Neogene materials are not obvious above sea level. But  seismic surveys on the continental shelf revealed a thick wedge  on the edge of the shelf thinning landwards. In fact those surveys revealed off central NSW a very thin cover of sediment overlying a rocks  Mesozoic age or even older. A few years ago Peter Cowell and I were pondering the origin of our cliffs. Alberto Albani had previously detected filled river valleys cut into the relatively smooth rock surface leading into the sediment wedge of the shelf edge. Jock Keene kindly showed us a set of seismic sections that confirmed this work and together we published our findings. Is this where the Neogene fits in?

We hypothesised that the eastern continental margin was subsiding since the Tasman Sea rifting ceased around 50 million years ago. Rivers draining the higher lands to the west were initially graded to sea levels on the shelf edge. As subsidence continued in the Neogene, the valleys were infilled and the wedge of sediment on the shelf edge continued to grow while to landwards a marine planation surface was cut as the cliffs were rolled back. Sea levels progressively got higher and higher reaching their present levels late in the Quaternary during high stands of glacial/interglacial cycles. So the Neogene sediments are not onshore but offshore along this coast.

The contrasting experience for me of working in these two coastal regions has been quite profound. It has highlighted two concepts: one the importance of relative sea levels in the interpretation of coastal history; and two that continental margins can be “emerged’’ while others can be “submerged”. Douglas Johnson back in 1919 made this distinction but for different reasons. Subsiding continental margins such as those of eastern Australian leave their own imprint on coastal landforms with cliffs, drowned valleys and lakes within sandy embayments. Emerged coasts show other features that are less dramatic but nonetheless  beautiful and intriguing.

– words by Prof. Bruce Thom 

By

ACS Communications Officer |

Sunday, September 6, 2015 |

  • Uncategorised
Category: Blog
Previous Post:COASTAL LAKES
Next Post:Trip to the Southwest Coast of WAMain Image

Sidebar

2022 (24)
  • Thursday, December 22 Protecting Nature: Art of the Impossible?
  • Tuesday, December 13 Drainage Window Concept
  • Thursday, November 24 Cootamundra Shoals Survey 1982
  • Thursday, November 10 US Coastal Zone Management Act 1972: A Model for Australia?
  • Wednesday, October 26 Great Barrier Reef—More or Less Gloom
  • Wednesday, October 12 Bondi Pavilion Reopened and Rejuvenated
  • Wednesday, September 28 Coastal Journey Begins: September 1962
  • Monday, September 12 Protection For Sydney Harbour: Berrys Bay Case
  • Thursday, August 25 Coastal Inundation: A Hazard Not to be Underestimated
  • Tuesday, August 9 Beach Access – An International Perspective
  • Wednesday, July 27 SoE 2021 and Coasts
  • Tuesday, July 19 Human Rights and Beaches
  • Wednesday, July 6 Coastal Walks and Local Councils
  • Thursday, June 23 EPBC Act and Regional Landscape and Resilience Plans
  • Wednesday, June 15 29th NSW Coastal Conference
  • Thursday, May 19 Lament for Estuaries? (0)
  • Wednesday, April 27 East Coast Floods 2022 (0)
  • Monday, April 11 East Coast Weather ‘Traffic Jam’ (0)
  • Tuesday, March 29 VALE: PAUL BISHOP (0)
  • Thursday, March 24 IPCC Throws Down the Gauntlet on Australian Institutional Deficiencies
  • Friday, February 25 Recent federal coastal initiatives – February 2022
  • Tuesday, February 8 Resourceful ‘lucky’ country
  • Friday, January 28 FUTURE EARTH AUSTRALIA: SUSTAINABLE OCEANS AND COASTS NATIONAL STRATEGY 2021-2030
  • Monday, January 10 Sunflowers and hope
2021 (27)
  • Wednesday, December 22 DISCOVERING MORUYA 1971-2021
  • Sunday, December 12 PROTECTING A BIG CITY: NEW YORK DECISION MAKING
  • Wednesday, December 1 ICA REPORT: CLIMATE CHANGE IMPACT “ACTIONS OF THE SEA” AND FUTURE RISKS
  • Friday, November 12 NATIONAL CLIMATE RESILIENCE AND ADAPTATION STRATEGY (NCRAS)
  • Thursday, October 28 COASTAL FAMILY—THE ELIOTS
  • Sunday, October 10 COASTAL CLIMATE CHANGE ADAPTATION: ROLES FOR THE AUSTRALIAN GOVERNMENT
  • Monday, September 27 Sydney Harbour: Impact of contamination studies
  • Friday, September 17 Geological indicators of seabed mobility – Narrabeen Beach (Sydney, Australia)
  • Monday, August 30 LAST INTERGLACIAL SEA LEVELS: RECENT RESEARCH AND MEET “STROMBUS BUBONIUS”
  • Wednesday, August 18   COASTAL NEWS – AUGUST 2021
  • Monday, July 19 Reflections on past coastal recommendations by the Australian Government
  • Monday, July 5 LARGS: A GEOHERITAGE SITE?
  • Thursday, June 24 PROPERTY RIGHTS: WHAT CONDITIONS PREVAIL IN A CIVIL SOCIETY?
  • Monday, June 14 UNIVERSITY RESEARCH—PERSONAL SADNESS
  • Saturday, May 29 SEAHORSE MONITORING BY WOOLLAHRA COUNCIL, NSW
  • Tuesday, May 18 US Climate Indicators
  • Saturday, May 8 AUSTRALIAN GOVERNMENT MARINE AND COAST INITIATIVES 2021
  • Sunday, April 25 Travelling west of the sandstone curtain – to Orange (NSW) and back
  • Tuesday, April 20 Big surf at Port Fairy (Victoria) – April 2021
  • Thursday, April 8 LAND: OWNERSHIP AND RIGHTS
  • Sunday, March 14 ESTUARY WETLANDS AND SEA-LEVEL RISE
  • Saturday, February 20 COASTAL ZONE AND CATCHMENT BOUNDARIES
  • Sunday, February 14 Coastal Archaeology Revisited
  • Saturday, January 30 JUDITH WRIGHT – POET, COASTAL CONSERVATIONIST AND MUCH MORE
  • Monday, January 18 COASTAL STORIES FROM THE FIELD,1970-2020
  • Monday, January 11 US COASTAL MANAGEMENT UNDER TRUMP
  • Monday, January 4 2020: A COASTAL PERSPECTIVE
2020 (26)
  • Wednesday, December 23 EPBC ACT CHANGES –WILL THEY BE WORTH THE EFFORT?
  • Monday, December 14 TWO JIMS—BOWLER AND COLEMAN
  • Thursday, November 26 AUSTRALIA UNDER THREAT—WHAT TO DO NEXT?
  • Saturday, November 7 SHORELINE RESPONSES TO SEA-LEVEL RISE
  • Sunday, October 25 Port Stephens-Myall Lakes 1960 – Research Opportunities
  • Wednesday, October 14 Port Stephens – Myall Lakes 1960 – the journey.
  • Monday, September 28 LEGACY ISSUES AND COASTAL MANAGEMENT
  • Friday, September 11 TYPHOONS AND HAINAN ISLAND, CHINA
  • Tuesday, September 1 Impact of sea-level rise on coastal natural values in Tasmania
  • Saturday, August 29 ENVIRONMENTAL VALUES REMAIN THREATENED
  • Thursday, August 6 HAMELIN POOL (Shark Bay, Western Australia) —AN ESTUARY?
  • Thursday, July 16 Estuary Health
  • Friday, July 3 UNIVERSITY RESEARCH AND TEACHING—THE NEXUS IS IT BROKEN?
  • Sunday, June 21 Sandy beach morphodynamics – a new book
  • Sunday, June 7 Cliffs in the Narrabeen Group, Sydney
  • Thursday, May 21 PROGNOSIS FOR A CHOKING MOUTH: THE RIVER MURRAY
  • Wednesday, May 6 Geomorphologic Mapping
  • Wednesday, April 22 DOVER HEIGHTS CLIFFS, SYDNEY
  • Sunday, April 12 Recent Coastal Legal Cases
  • Tuesday, March 24 CHALLENGE AND RESPONSE—THE CURRENT CRISIS
  • Wednesday, March 18 Recent papers in the journal Nature
  • Thursday, February 27 HOLOCENE SEA LEVELS AND COASTAL EVOLUTION
  • Monday, February 17 Brian Caton ‘a coastal legend’- RIP 9 February 2020
  • Tuesday, February 4 NATIONAL COASTAL ADAPTATION AGENDA 2010: A RETROSPECTIVE
  • Wednesday, January 22 TIME FOR ADAPTATION ACTION
  • Friday, January 10 EAST COAST FLOODS 2022 (0)
2019 (29)
  • Monday, December 30 Parsley Bay in the Summer
  • Monday, November 25 Australian Coastal Systems: A New Book from Andy Short
  • Tuesday, November 19 South Australian 2019 Coastal Conference and the ACS AGM
  • Wednesday, November 6 28th Annual NSW Coastal Conference – Terrigal, 2019
  • Sunday, October 27 Coastal Incidents
  • Tuesday, October 8 Coastal morphostratigraphy: two papers from Denmark
  • Friday, September 27 Climate Change Attribution
  • Tuesday, September 10 Vale Jack Davies at age 97 – leader, teacher and mentor
  • Wednesday, September 4 Coastal erosion and accretion beyond the historical timescale in NSW
  • Monday, August 19 Rethinking Landscape in Aotearoa
  • Friday, August 2 Collaborative Science and Coastal Adaptation
  • Saturday, July 20 CLIMATE CHANGE AND RELATIVITY – SOME PARALLELS
  • Sunday, July 14 DOUGLAS W. JOHNSON 1919 AND BEYOND
  • Tuesday, July 2 The Sandiford Line
  • Saturday, June 22 A Curiosity of Cusps
  • Monday, June 3 Federal Election 2019 and Coasts
  • Monday, May 13 Mangrove Generations
  • Sunday, May 5 John Sinclair of K’Gari (Fraser Island) 1939 – 2019
  • Monday, April 22 The Mighty Ord
  • Thursday, March 28 Climate change adaptation: perspectives from Canada and England
  • Monday, March 18 Foreshore land grants in eastern Sydney
  • Friday, March 15 The right to bath on the beach
  • Wednesday, March 6 Victorian Coastal Monitoring Program
  • Thursday, February 21 Future national need for a healthy environment
  • Wednesday, February 13 ANZGG CONFERENCE AT INVERLOCH, VICTORIA
  • Wednesday, February 6 Coastal science and the Murray River mouth
  • Saturday, February 2 INDIA COASTAL MANAGEMENT
  • Tuesday, January 15 Sydney Harbour Sea Fog – Summer of 2018/2019
  • Saturday, January 5 COASTAL RESILIENCE AND ADAPTATION
2018 (31)
  • Monday, December 17 CLIFF-TOP DUNES
  • Saturday, December 15 The whereabouts of climate change adaptation
  • Sunday, December 2 Observations from a long time marine debris collector.
  • Sunday, December 2 Backbarrier flats – a relic coastal landform
  • Monday, November 19 King Tides in Venice
  • Wednesday, November 14 27TH NSW COASTAL CONFERENCE 2018
  • Monday, November 12 Is the coast losing out with NRM? Proposed changes for South Australia
  • Saturday, November 3 Slicks (Part 2)
  • Tuesday, October 16 Twofold Bay – A Great Coastal Laboratory
  • Sunday, October 7 VALE: Professor John Chappell FAA (1940-2018)
  • Thursday, September 27 Coasts and Legal Systems
  • Sunday, September 16 Moods of Sydney Harbour
  • Sunday, August 26 Community Consultation
  • Saturday, August 18 Managing water quality through regenerative agriculture
  • Friday, August 3 Tomorrow’s Coasts – Complex and Impermanent
  • Thursday, July 12 Murray-Darling Basin Royal Commission
  • Monday, July 2 New South Wales Coastal Reforms – NSW Coastal Council’s first meeting
  • Tuesday, June 26 Victoria’s Coastal Reforms – ‘fit for purpose’ or an opportunity lost?
  • Wednesday, June 20 New SA Government promises improved coastal management
  • Thursday, June 14 OCCUPATION OF THE AUSTRALIAN CONTINENTAL SHELF
  • Wednesday, May 30 National Budgets – Some Thoughts
  • Wednesday, May 16 Guiding Principles for Marine and Coastal Management
  • Friday, May 4 Last Interglacial Marine Deposits at Mary Ann Bay, Tasmania
  • Sunday, April 29 Coast to Coast Hobart 2018
  • Thursday, April 5 Coastal Reforms in New South Wales – The Next Stage
  • Monday, March 26 Coastal Archaeology
  • Monday, March 12 Barrier Islands – An American Obsession?
  • Monday, February 26 Climate Change Adaptation in Australia – A Loss of Momentum
  • Thursday, February 15 Bruce Thom Blog – SUMMERAMA
  • Wednesday, January 31 King tides and extreme events
  • Sunday, January 14 Coastal Geomorphology 101
2017 (39)
  • Friday, December 29 Bruce Thom Blog – Speaking Truth to Power
  • Wednesday, December 20 National Surfing Reserves
  • Thursday, December 14 Beachrock
  • Saturday, December 9 Higher Tides
  • Monday, December 4 Keeping the Murray Mouth open
  • Monday, November 27 Victorian Coastal Management in 2017
  • Thursday, November 16 26th NSW Coastal Conference at Port Stephens
  • Thursday, October 26 Ancestral rivers and terraces
  • Monday, October 16 Murray Valley: a recent visit
  • Wednesday, October 11 The National Construction Code and coastal planning
  • Tuesday, September 19 Geomorphic evolution of Coorong, Lower Lakes and Murray Mouth
  • Wednesday, September 13 Queensland Coastal Conference 2017 – Ten years in the making
  • Tuesday, September 5 Hurricane Harvey and its implications
  • Friday, September 1 Gippsland (Victoria) and relative sea level rise
  • Sunday, August 27 US Office of Naval Research and the Australian Coast
  • Monday, August 21 Managing the unique wetlands of Gippsland Lakes
  • Thursday, August 10 Lifecycle of coastal environmental law
  • Friday, July 28 Charlie Veron – A Life Underwater
  • Sunday, July 23 Coastal Sediment Management
  • Friday, July 7 Coastal walks -Malabar Headland National Park, Sydney
  • Friday, June 30 Honeycomb Weathering
  • Friday, June 23 Disaster preparedness
  • Wednesday, May 31 Sept-Iles: Managing a migrating foreland
  • Wednesday, May 24 Achievements of the National Climate Change Adaptation Research Facility
  • Saturday, May 13 Coastal Shacks
  • Wednesday, April 26 Empress Augusta Bay, Bougainville
  • Thursday, April 20 The Blue Mud Bay case – Aboriginal property rights in the Northern Territory
  • Tuesday, April 4 Botany Bay Sands
  • Saturday, March 25 Wave Energy Resource
  • Wednesday, March 15 Clustering of Storms
  • Wednesday, March 15 Cape to Cape: A voyage around Botany Bay
  • Tuesday, March 7 The “Venice Effect”
  • Monday, February 27 Port Stephens Bioherms
  • Thursday, February 9 Coast Ambassadors
  • Friday, February 3 Coastal Graphics
  • Tuesday, January 31 Irukandji on the move
  • Tuesday, January 24 Acceleration in mean sea level
  • Wednesday, January 11 Concerns of an American coastal scientist under a Trump presidency
  • Sunday, January 8 EXTREME STORM EVENTS IN THE USA, AUGUST-SEPTEMBER 2021
  • About us
  • Get involved
  • News and events
  • Resources
  • Blog
  • Contact us

Banner Photography by Pixabay

© 2023 Australian Coastal Society. All Rights Reserved.

  • Facebook
  • Twitter
  • Mail
  • LinkedIn