It may not be a meteorite crater, but the origins of Wee Jasper's unusual depression remain a mystery. Since first discovered by fine wool producer Ian Cathles on the escarpment of Cooradigbee, his 3000-hectare property on the western shores of Burrinjuck Dam, over a decade ago, a number of amateur geologists had hypothesised that the 70-metre diameter crater may have been the result of a meteorite strike. Due to its hard-to-reach location, no experts had ever examined the naturally-occurring hole firsthand.
However, in response to this column's exclusive expose´ on the far-flung ''crater'' (It's a ''hole'' lotta fun, September 22, 2012), an international team of geologists recently accompanied Cathles to the site.
After a comprehensive investigation of the crater and its immediate surrounds, the trio, comprising Iona Summerson (undertaking a master's degree at the Free University in Berlin researching impact structures in a Martian meteorite found in Morocco), her father Rupert (a self-confessed ''lapsed geologist'') and Dr Richard Blewett (Group Leader, Regional Geology & Mineral Systems at Geoscience Australia) have poured cold water on the meteorite crater hypothesis.
''No evidence could be found for impact by a meteorite,'' states the detailed scientific report on their expedition, prepared for this column. ''A meteorite with sufficient mass to leave a crater 70 metres in diameter would most likely have resulted in some impact structures, but, apart from its roughly circular form, no other distinctive feature or features of meteorite impact were found.''
The trio further articulate other geological processes that may have created the crater, including deflation (preferential wind action), a subsidiary fault and the existence of sink holes. ''These processes, either alone or in combination, could be sufficient to cause the depression,'' claim the trio, who recommend further research be undertaken at the site in order to determine the crater's true origins.
Oh, how I love a good mystery.
Mystery Hole: If you want to check it out for yourself, join one of Cooradigbee’s full day tours. Price dependent on numbers and catering options (if you don’t want to pack you own sandwiches, the Cathles will prepare you a gourmet picnic). Contact: www.weejasper.com.au or phone Ian and Helen Cathles on 02 62279634.
Geology Bible: When Dr Richard Blewett is traipsing around mystery craters, he’s busy at work in the Geoscience Australia bunker. He’s latest output is the stunning 500 page coffee table book Shaping a Nation, A Geology of Australia (Geoscience Australia and the ANU Press, 2012) of which he is Chief Editor. While the knock-out tome doesn’t include Cooradigbee’s crater, through a mix of engaging text and striking images it showcases our continent's geology through its impact on the people. It is available at epress.anu.edu.au/titles/shaping-a-nation for free download and limited hard copies are available for purchase for $70 (plus postage costs) from Geoscience Australia (www.ga.gov.au).
What: The Bungendore Show - billed as the ''best one-day show in Australia''.
Where: Bungendore Showground is located three kilometres west of Bungendore on Mathews Lane, off Bungendore Road (left turn coming from Bungendore, right turn coming from Federal Highway).
When: Tomorrow, 9am-4pm.
Cost: adults $15, children under 15, free.
Expect: Fun for all the family, including the traditional agricultural pavilion, an action-packed horse and equestrian program, puppet theatres, pet parades, dog races, roving magicians, live music and, of course, sideshow alley.
Don't miss: The Star Picket competition. Watch ''drivers-in'' and ''pullers-out'' compete against each other and the clock.
Tim's tip: Stay well clear of over-enthusiastic star picket competitor Phill Sledge, of Kaleen (pictured), who has an uncanny ability to swing his hammer before you've moved your hand. Ouch!
Several readers responded to my recent request for photos of the currently dry Tianjara Falls (near Nerriga) in wetter times (Rest Stop #7, January 12). Ken Charlton came to the party with a photo of the falls in July 2011 '' when there was plenty of water falling''. Phil Parnell, of Chapman, who regularly drove the road when he lived in Nowra for 18 years, snapped a photo of the falls in their full glory after heavy rains in autumn 2011. While Charlton and Parnell took their photos from the relative safety of a viewing platform, in April 2012, daredevil contributor to this column Kim Pullen ''cut through the bush to an unfenced (and rather hazardous) spot on the cliff top nearer the falls,'' to capture his impressive image (see above) of water plunging over the falls. ''There is a nice little pocket of rainforest at the head of the gorge, under the falls,'' Pullen says.
If you've been caught in the traffic queues at the bottom of the Clyde during the recent heatwave, you could easily be excused for thinking that half of Canberra has migrated to the coast for some relief. However, Marjorie Curtis, of Kaleen, reports that you don't even have to leave the comfort of your Canberra couch to experience the ''real taste of an Australian summer''. On one of our recent run of scorchers Curtis was sitting ''reading peacefully'' in her family room when a movement on the floor made her look up. ''I was astonished to see a three-foot long black or dark brown snake coming (fast) towards me with its head raised,'' reports Curtis, who, not surprisingly, jumped and dropped her book. ''Whereupon the snake turned around and headed for the kitchen door! I tiptoed round the house looking for it, afraid that it might spend time in my bedroom.'' Curtis promptly contacted the police, who put her in contact with a wildlife ranger. ''He arrived in less than 10 minutes, and eventually caught the snake (probably an eastern brown),'' reports a relieved Curtis. As for the plight of Curtis's uninvited visitor? At last report, it was seen slithering out of the ranger's hessian sack into the grassland at the old Belconnen naval communications base (soon to be the new suburb of Lawson).
Curtis would like to offer bouquets to both the police officer and the ranger who she says, ''handled the situation calmly and efficiently''. For the record, the ACT government advises the best number to call if you need a snake removed from your home or garden is Canberra Connect on 13 22 81. If it's a life-threatening situation, call 000.
This column's erudite birding correspondent, Geoffrey Dabb, was quick to comment on this column's recent feature on the Rowes Lagoon rest area on the Federal Highway near Collector (Perfect rest spot, December 29, 2012) - although, somewhat surprisingly, his comments concerned water catchment intricacies rather than the avian activity. ''The lagoon is part of the blind depression leading to Lake George, so if you are near the lagoon and nature calls, depending on where you take your pee, the ultimate destination might be the Pacific Ocean via the Wollondilly River, the Southern Ocean via the Lachlan River,'' Dabb reveals.
While I recognise that Dabb might find himself in more remote locations than most of us, for the record, the Rowes Lagoon Rest Area does have toilet facilities.
Email: firstname.lastname@example.org or Twitter: @TimYowie or write to me c/o The Canberra Times, 9 Pirie St, Fyshwick.
BEST REST STOP #8
The final roadside feature in this summer series is more of a point of interest than an official rest stop and is recommended by Ray Scarlett of Evatt, a local tour bus driver with a penchant for fascinating insights into our region's history.
Where: The remains of the old timber town of Monga, featuring a large waterwheel on the side of the Kings Highway near the top of Clyde Mountain. If heading to the coast, soon after crossing the Mongarlowe River, just prior to the turn-off on the right (River Forest Road) to Monga National Park, the waterwheel is visible on the left behind a house. ''Although you can see the wheel while driving the highway, if you want a closer look take the National Park turn-off, park a safe distance down the road, then walk back up to the highway,'' Scarlett suggests.
Please note: These ruins are not signposted and are predominantly on private land, so you can only view them from afar. Warning: The highway can be very busy, so please exercise extreme caution if slowing down or exploring on foot. Alternatively, a safer option might be to ''get the kids to try and spot the wheel from the back seat'', Scarlett suggests.
Why: ''In summer thousands of Canberrans drive past this site on the way to the coast, most oblivious to its significance,'' Scarlett says. ''During its logging heyday early last century, about a dozen sawmills operated at this site, processing the large cedar logs dragged out of the surrounding forest. If you look closely you can see other remnants of the small town which collapsed once the cedar ran out.'' Scarlett says the waterwheel was built in 1907, ''but was reconstructed using the original gearwheels and shaft in 1986 and could turn a blade at 600 rpm.''