We started the year with two presentations by our own members, followed by a picnic tea/ BBQ (bring your own) in Halls Gap afterwards.
The first was presented by Ben Gunn, an archaeologist residing at Lake Lonsdale. Ben recently gained a Ph D for his work. Over the years Ben has spoken to FOGGS about local art sites, and we knew he was also doing much work in the north of the country so we were very much interested in hearing about what he had learnt.
“Art of the Ancestors: Analysing ceiling art of Nawarla Gabarnmang in Arnhem Land”
Ben’s thesis was about the development of a new way of recording and analysing rock art by incorporating three techniques: DStretch from rock art, Harris Matrix from archaeology and the Morellian Method from fine art. Using the ceiling art from Nawarla Gabarnmang in western Arnhem Land he was able to show that at least 113 layers of painting have decorated this ceiling. These layers were aggregated into seven assemblages, based on stylistic and sequential similarities. On the basis of other archaeological and environmental evidence the each assemblage was then allocated an age. The chronology showed that there was a major change in pigment colour preference around 500 years ago: from red to white. The reason for this change is still being investigated.
Ben then briefly showed how this method can be applied to the rock art in Grampians-Gariwerd, placing the very first petroglyph found here (which was really exciting) within the Gariwerd sequence:
- Most Recent:
A single petroglyph
- Earliest Art:
In the next few years Ben hopes to expand this study and re-evaluate the whole Gariwerd sequence (and hopefully tie it into some dates).
The second presentation was by Bill Gardner who lives at Laharum in the Northern Grampians. Bill is a newer member of FOGGS and gained his Ph D in 1981 studying
“ The soil/root interface of Lupinus albus”
What relevance does that have for the Grampians? you might ask. Well read on.
Bill studied for his PhD from 1978-81 at Melbourne University, examining the soil/root interface of white lupins. The initial aim was to see if some kind of mycorrhizal (beneficial fungi helping plants take up nutrients) interaction was occurring in farm rotations, but the absence of any mycorrhizae on the lupins sent him off into unchartered territory. He discovered white lupins produce root clusters (sometimes called proteoid roots in the Proteacea, or dauciform roots in rushes) and used various chemical secretions to cause parts of the soil, in particular iron, aluminium and manganese, to dissolve, thereby obtaining nutrients locked away from other plants. Some plants species with similar adaptations have quite extra-ordinary amounts of manganese or aluminium in their above ground parts, indicating a terra forming ability on the soil. In recent years, Bill has been looking at chemical scalds near Balmoral caused by groundwater containing iron and sulphur interacting at the surface in a similar fashion to acid mine drainage, albeit on a smaller scale. Soil pores become blocked with iron oxides, causing the watertable to rise. A technique involving rushes and other root cluster forming species is showing promise by dissolving the iron oxide thereby increasing discharge and restoring water balance in the landscape.
The picture below shows roots of white lupins growing in an agar slant containing black insoluble manganese dioxide, which has been chemically altered and dissolved around the root clusters.
Both talks gave rise to many questions which both speakers generously helping us understand the implications for our area.