LOESSFEST'09 | Aug. 31st – Sept. 3rd, 2009 |Novi Sad-Serbia
Two-Thirds of the WPWG; Australia and New Zealand as Loess Regions
O’Hara-Dhand1, K., Smalley1, I., Wynn1, P.
1Giotto Loess Research Group, Waverley Materials Project, Nottingham Trent University, Nottingham NG1 4BU, UK;
The Western Pacific Working Group WPWG of the INQUA Loess Commission was set up in 1977 to focus attention on loess research in China, Australia and New Zealand- countries of the Western Pacific region. China is now, of course, the giant of loess research but Australia and New Zealand remain rather on the fringe of the loess world. Loess in New Zealand was identified by Julius von Haast when he arrived from Europe; there is a long history of investigation of the New Zealand loess with the highlight being the discovery of loess stratigraphy by John Hardcastle at Timaru in 1890.
But what about Australia? David Haberlah has re-ignited the discussion on loess in Australia and various aspects are up for consideration again. Bruce Butler claimed to find no loess in Australia and his findings (lack of findings) have been much quoted in the desert loess debate. So we start from the position that there are no significant deposits of traditional loess in Australia. But until recently exactly the same could be said of England- and now we know and appreciate a considerable loessic world in S.E.England, with a well established literature trail. All that was needed was a careful re-examination and a lowering of the sights. Also we now appreciate that loess material can be delivered into a landscape and not participate in the formation of an obvious loess deposit.
Look for loess deposits where they might be found; an inductive approach to loess. The River Tisza flows from the Carpathian mountains into the Great Hungarian Plain, and eventally joins the Danube. It delivers loess material, it is associated with loess deposits. Particle source, transporting river, depositional environment- all that is required for a loess deposit to form. Transpose the scene to S.E.Australia- this is a region where loess (traces of loess) should be found. The south-east of Australia has the requisite mountains and rivers, there should be traces of loess.
There is another angle to Australian loess that should be explored: the idea that large amounts of silt sized material might be introduced into the sedimentary system as clay mineral agglomerate particles (CMA). The CMA particles are produced from old lake basins, in fact they provide much of the dust material which is blown out of North Africa- and there are roughly equivalent lake basins in Australia. CMA particles tend to make small dust (using the Stuut et al terminology) but it is possible that CMA large dust exists. It should be sought (is it Bruce Butler’s Parna?). There is a literature trail for parna and it is studied and discussed but more sedimentological detail is required; how are the particles formed? What is the true extent of parna deposits? Is it related to traditional loess or to CMA loess? Clarification is required. Some clarification in NZ as well; the South Island looks like a proper loess place- high recent mountains, quite a bit of glacierization, some handsome rivers; the South Island loess is located in expected places. But the North Island loess(identified by Des Cowie not that long ago) needs more consideration from the sedimentological point of view. Whence the particles? Which were the best rivers? How close to classic loess is it??