Port Stephens-Myall Lakes 1960 - Research Opportunities

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In 1960 as an honours student in Geography at University of Sydney, I was given an incredible gift. To be free to choose a topic and an area for thesis research, a choice in retrospect that guided my future. Both timing and location was perfect as there was sufficient background material in the literature and diversity of coastal landforms to investigate to keep me busy.

Timing was perfect. Eric Bird’s Gippsland 1959 PhD was a catalyst made available to me by Joe Jennings his supervisor at ANU. Joe had just published work on aeolian geomorphology of King Island and these publications plus his mentoring early in 1960 gave me confidence to go into the field. Trevor Langford-Smith offered both encouragement and access to a copy of the proceedings of the Second Coastal Geography Conference held at LSU in Baton Rouge in April 1959. This was a remarkable volume and later stimulated me to do postgraduate studies at LSU; its relevance will be discussed below. Through access to the NSW Mines Department Library I was able to see two relatively recent studies that offered background to what I was about to encounter in the field: Gardner’s monumental 1955 report on heavy-mineral deposits of eastern Australia (BMR Bulletin 28) and Cooper’s 1958 study of sand dunes of Oregon and Washington (Memoir 72, Geol. Soc. America). Without all these studies I could not have conceptualised this topic.

The area was perfect. North of Newcastle there were a number of discrete coastal compartments each with a distinctive suite of depositional landforms. In the thesis these spatial units were termed “segments”. The area was ripe for investigation. With the exception of Gardner’s work that focussed more on northern NSW—SE Qld, little systematic mapping and Quaternary research had been conducted on depositional features in NSW. Aerial photos offered me an overview of a diverse array of aeolian and beach landforms which had never been described. What existed were reports from an older generation of geologists and botanists that highlighted the need for a more systematic regional geomorphic approach similar to those of Bird, Jennings and what had just come out on the coast of Oregon and Texas.

It was not too difficult to develop a conceptual framework given the reading and mentoring, the availability of an excellent set of air photos, and support from two local geologists and a ground-water chemist. One was Brian Engel of Newcastle University. He was busy mapping the bedrock geology of the Carboniferous sequence. Although I was just a geography undergraduate, he found time to discuss my Quaternary mapping (this was odd because Sydney University geologists at the time thought geology stopped at the Permian!). The other geologist was Peter McKenzie then with BHP but who had just finished his rip-current study at Dee Why as part of a MSc thesis at UNSW. Peter generously made time available to visit me in the field and amongst other things alert me to that wonderful flight of cusps at the west end of Shoal Bay. He also put me in touch with staff of one of the heavy mineral companies that were about to do more drilling in the area. In later years, these contacts became very helpful. The third person was a remarkably generous chemist employed by the Hunter District Water Board (HDWB). He opened my eyes to the subsurface beneath deposits from Tomago to Seal Rocks where sand bodies had been investigated for ground water supplies. Looking back, bore logs he supplied was one of the most important data sets that I had access to for this thesis.

The conceptual framework followed the model of Bird in Gippsland involving Inner and Outer barriers. I called these bay barriers following the nomenclature set out in a paper in 1952 by Shepard. Where I differed from Bird at the time was that based on drill logs, soil type and air photo interpretation, the Inner Barrier was Pleistocene not Recent/Holocene in age. An air photo in the  paper by LeBlanc and Hodgson (1959, Fig. 20) adjoining San Antonia Bay in Texas in the  LSU conference proceedings showed remarkable similarities in beach-ridge topographic form to what I was seeing in several “segments” of the thesis area. Jennings had alerted me to look out for the difference between subdued v fresh morphologic condition that he had noted in King Island. The contrast also applied to dune features. But what sealed it for me were those drill logs and the existence of what the HDWB termed “Woolloomooloo” or coffee rock extending below sea level beneath all Inner barriers but absent below Recent/Holocene Outer barriers. Interestingly I discovered a similar contrast 5 years later in my PhD research in Horry County, South Carolina. And to confirm the age difference, the HDWB obtained a background C14 date on an Anadara shell below the coffee rock at Tomago. John Marshall and I published in Nature in 1976 uranium series dates on corals from the rear of the Inner Barrier at Grahamstown confirming a Last Interglacial (Stage 5e) age for the deposits.

Ten weeks in the field in 1960 was full of new findings. Dune morphology became a focus given the existence of a variety of both mobile and stabilised dune types. West winds in May that year had transferred the active sand sheet of Newcastle Bight into a remarkable field of asymmetric transverse dunes. Cooper’s 1958 memoir came to light and for each segment I was able to map each dune type and compare features with what he had described. I enjoyed traversing these dunes and observing soil and vegetation patterns. I borrowed the term “transgressive dune” from Gardner in place of Cooper’s term “precipitation ridge” which he applied to active slipcase of sand invading a forest. In an exchange of letters Cooper told me what he thought of my use of terms and interpretations on modes of stabilisation by vegetation. There was a slight difference of view!

The Myall Lakes area was the subject of an amazing report following the expeditions of Sydney University Rover Scouts in the 1930s (see paper by Osborn and Robertson in Proc. Linnean Soc., NSW, 1939, v 64). This work provided me with botanical guidance although I was also able to turn to current staff in the Botany School for advice, especially the palynologist Tony Martin with whom I later published. What they noted about the area in 1939 remained true in 1960 and thankfully to a large degree to the present: “Though the area has been inhabited by white men for over a century, much of it, especially the dunes, heaths and swamps, is still in a primitive state” (p.279).  More substantial ecological work in the Eurunderee segment was later undertaken by Caroline and Myerscough (Cunninghamia, 1986, 1, (4), 399-466) also from Sydney University. They utilised my geomorphic work by then published in part in a paper in the Journal of Royal Society NSW (1965, v.98, 23-36).

Looking back at that 1960 thesis I am reminded how much I learnt in one year and just how grateful I am now for the chance to have been a geography student at that time. Fortunately, I was able to return armed with a drill rig in the 1970s. But more important was that the area became a location for many others to study. In the 1960s Mike Shepherd completed a PhD on part of the area north of Hawks Nest. Pat Hesp, Cheng Ly, and Greg Bowman all undertook PhD research that used sites here and contributed significantly to our understanding of coastal sediment dynamics and evolution. Peter Roy from the NSW Geological Survey also worked in the area with us especially in the Port Stephens estuary. Many publications have resulted. We attempted to bring much of this together in a monograph in 1992 (Thom et al., 1992, Coastal Geomorphology and Quaternary Geology of the Port Stephens-Myall Lakes Area, Monograph No. 6. ANU Dept. Biogeography and Geomorphology, Monograph No. 6, 407pp.).

Words by Prof Bruce Thom. Please respect the author’s thoughts and reference appropriately: (c) ACS, 2020. For correspondence about this blog post please email austcoastsoc@gmail.com