From Arnhem Land Day 9, Mt Borrodaile day
The things we learnt or saw, from Driver Ian, en-route
These sound a bit ad hoc when listed here, but they were all relevant:
- the very thin Magnetic (now called Meridian) termite mounds were here in prehistoric times, in Gondwanaland. They used to be called Magnetic, the name we knew them by when we were last up this way, as it was felt they were aligned to the Poles, but it is now believed they are east-west aligned so that one side faces east, and the other west, enabling the termites to manage heat. You can feel the temperature difference when you touch the two sides (which we did another day because we couldn’t stop here could we?)
- Arnhem Land’s sand makes its way to other continents, Ian told us. Indeed he suggested that as Australia is the world’s oldest continent and as sand comes from weathering, that much of the world’s sand originated in Australia. We hadn’t heard this before, and my quick Google check didn’t really answer the question one way or another.
- Djelk Rangers are a pioneering Indigenous land management program formed around 20 years ago by TOs from the Maningrida area of Western Arnhem Land to keep their country healthy and culture strong, as the result of concerns about the environment, including the problem of invasive weeds and feral animals. One of their tasks, Ian said, was to clear mimosa weed. I loved hearing firsthand about self-directed programs like this.
- cats and rabbits are banned in much of the North
- burnt country, created by indigenous patch burning practice, is much easier to easier to walk through. Leichhardt discovered this when he ventured into Arnhem Land during his Second Expedition, 1844-45. Ian clearly admired Leichhardt’s achievement in crossing the plateau here, and told several stories about him.
- introduced animals (including dingoes around 4,000 years ago, buffaloes, and deer) have been incorporated by indigenous people into their songlines
- spalling erosion (flaking) is a major factor here in sandstone country
- freshwater crocs need sand to lay eggs, and they need 29°C to produce 50% males and females. If it’s cooler, the eggs produce males, if warmer, it’s females. Increasing temperatures are posing a threat to those reptiles where sex is determined by temperature.
- whistling kite nests are often found near jabiru (Black-necked stork) nests as they use the twigs rejected by the jabirus
- Philip Parker King, son of Australia’s second governor, Philip Gidley King, was Australia’s first navigator. He was the first to chart this area, and named made features including the Alligator River system.
- the pretty palm, the Livistona Inermis, is confined pretty much to the Mt Borrodaile area
- early Arnhem Land anthropologists included Balwyn Spencer who in 1902 was the first white man many had ever met and who produced a photographic book of Arnhem Land; Donald Thompson whom we mentioned in an earlier post; and CP Mountford who led the Greater Arnhem Land Expedition in 1948.
Plus some background about rock art:
- Pre-estuarine period, ie before sea levels rose up to 20,000 years ago: paintings of diprodons, bigger macropods, in red haematite. If a painting is not done in red haematite, it can’t be that age, but haematite was used for a long time so haematite paintings can be younger.
- The oldest style of art were hand prints, objects thrown at the rock surface, grass prints
- Next were large naturalistic animals, still in haematite
- Then came yam figures (which are round) and dynamic figures (which are shown being active, such as throwing spears). These date around 9-15,000 years ago
- Estuarine period, around 6,000 years ago, is represented by the X-ray descriptive style
- By 2,000 yeas ago, X-ray decorative art was being used
Leichhardt’s Grasshopper: It is only found in that plant, a pityordia (Check). Brightly coloured insects are usually toxic, but these, apparently, have an awful taste but aren’t toxic.