A Review of Sea-Level Change on the Southeast Coast of Australia

A revised Holocene sea-level curve for the southeast coast of New South Wales, Australia, is presented
based on a review of previously published geochronological results for fossil molluscs, organic-rich
mud, mangrove roots and fixed biological indicators. It is supplemented by new radiocarbon and amino acid
racemization-derived ages on fossil molluscs from transgressive sandsheet facies in back-barrier settings within
shallow incised valleys along the southern coast of New South Wales. This data base has been limited to fossils
with accurate descriptions of their facies associations and stratigraphic relationships to present mean sea
level. Results show that sea level during the Holocene marine transgression rose to between −15 and −11 m at
9400–9000 cal. yr BP. Sea level then rose to approximately −5 m by 8500 cal. yr BP and to approximately
−3.5 m between 8300 and 8000 cal. yr BP inundating shallow incised valleys resulting in the deposition of
shell-rich transgressive sandsheets within shallow incised bedrock valleys. Present sea level was attained
between 7900 and 7700 cal. yr BP, approximately 700–900 years earlier than previously proposed. Sea level
continued to rise to between +1 and +1.5 m between 7700 and 7400 cal. yr BP, followed by a sea-level highstand that lasted until about 2000 cal. yr BP followed by a gradual fall to present.
A series of minor negative
and positive oscillations in relative sea level during the late-Holocene sea-level highstand appear to be superimposed over the general sea-level trend. However, the precise nature of the oscillations are difficult to quantify because of problems associated with accurately determining palaeotidal and wave regimes, climatic
conditions and the antecedent morphology of the shallow marine environments during the mid Holocene.

Holocene sea-level change on the southeast coast of Australia: a review

Craig R. Sloss
School of Earth & Environmental Sciences, University of Wollongong, Wollongong NSW 2522, Australia, c.r.sloss@massey.ac.nz

The Holocene, Vol. 17, No. 7, 999-1014 (2007)DOI: 10.1177/0959683607082415

Colin V. Murray-Wallace

School of Earth & Environmental Sciences, University of Wollongong, Wollongong NSW 2522, Australia

Brian G. Jones

School of Earth & Environmental Sciences, University of Wollongong, Wollongong NSW 2522, Australia

15 Responses to A Review of Sea-Level Change on the Southeast Coast of Australia

  1. Ric Fennessy November 15, 2007 at 9:50 pm #

    Is there some point to this posting that is relevant to this blog????

  2. Paul Biggs November 15, 2007 at 10:06 pm #

    Err – climate change, Sea Levels, Australia?

  3. Nexus 6 November 16, 2007 at 11:15 am #

    Paul, constantly posting media snippets and paper abstracts with no analysis or putting them into context makes for a boring blog. I’m afraid the standard here has really dropped (and that’s got nothing to do with actually agreeing or disagreeing with the subject of the posts). Perhaps put some more effort into the posts themselves and less into scouring the media for stuff that, I suspect, many readers here have come across somewhere else.

  4. Ian Mott November 16, 2007 at 11:17 am #

    How about the fact that Sea Level peaked some 2000 years ago and has been in gradual decline since then. Ergo;

    1. The much trumpeted sea level rises over the past century are entirely within the historical range of variation, and

    2. The past peak of sea level took place without anthopogenic CO2 emissions, and

    3. Sea level will need to rise a lot more than just a few metres before any “tipping point” kicks in.

  5. Ian Mott November 16, 2007 at 11:22 am #

    Nexus has exhibited a distinct pattern of claiming that the standards of this blog has declined. Could this have anything to do with the fact that he has a competing blog?

    I appreciated the posting of this item. Onyabikeyabum.

  6. Nexus 6 November 16, 2007 at 11:57 am #

    Ian, I don’t have a competing blog (unless snarky cartoons have been posted here and I’ve missed them) and due to way too much work haven’t been blogging at all lately. Anyway, my blog is as boring as hell and I recommend no one read it.

    In the past I have often found this blog an interesting source of opinion, some of which I agree with and some of which I don’t.

    However, in my view blogging should be about an ‘independence’ take on, in this case, science and politics. Not just repeating ad infinitum what is already out there. Sure, post the item, but say what you think about it as well. Why is it important? How does it sit with the current body of knowledge?

  7. Nexus 6 November 16, 2007 at 11:58 am #

    bah… independent take.

  8. jennifer marohasy November 16, 2007 at 12:57 pm #

    The abstract from the technical paper is very difficult to understand – lots of jargon. And yes, what is Paul’s take on it?

    It would be nice if the first few sentences of each blog post were in plain english.

  9. gavin November 16, 2007 at 1:43 pm #

    Jennifer: It’s all about rates of change between 7800 and 7550 BP if you are considering twinkle toes by the shore.

  10. Louis Hissink November 16, 2007 at 6:09 pm #

    Rule of thumb when abstracts are as obtuse as Jennifer points to is that the subject matter is controversial, no one agrees, and the paper is submitted to ensure that the authors are “doing” something.

    I’ve read it and conclude: “So what?”.

  11. Paul Biggs November 16, 2007 at 6:24 pm #

    I highlighted the significant sentences, which are self explanatory without the need for any technical knowledge.

    Sea levels have fallen to the present level since the ‘highstand’ of 2000 years ago, on the Southeast coast.

  12. Louis Hissink November 16, 2007 at 6:43 pm #

    Right, they have, as “observed” and “measured”.

    So what?

  13. Paul Biggs November 16, 2007 at 7:50 pm #

    It makes a change from alarmism about rising sea levels.

  14. James Mayeau November 19, 2007 at 9:49 am #

    Paul – I immediately grasped the significance of past ocean fluctuation. We are in a struggle with people of some stature in the climate science community who are hell bent on creating the impression that there is no such thing as natural climate variability. This study shows that CO2 isn’t in the driver seat.

  15. Luke November 22, 2007 at 7:22 pm #

    Like who. Try not be totally stupid James.
    I can see James can only keep one variable in his linear brain at one time.

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