Lawn Hill Impact Structure
18° 40.80' S  138° 37.41' E

Earth Impact Database info


I visited the Lawn Hill Impact Structure in June 2008. I was staying in Adel's Grove while assisting with tourism research at the Australian Fossil Mammal Site (Riversleigh) World Heritage Area. Having found out that the crater area in question did not require additional permission to visit, two aquaintences and I headed off for an adventure.

Driving instructions...
From Adel's Grove, drive back towards Gregory Downs about 5km. At a line of hills, a road heads off to the south. This is also the road to the western entrance of the Zinifex Century Mine (whose name will probably change another time or two...). Carry on until you arrive at the gate to the mine. You can pull off to the side of the road here, or drive along the fenceline to the north for a hundred meters or so.  (Note: 10-20 meters north of the gate, the quality of the fence will change, you Do Not want to be wandering along the area inside the better quality fence! Pull out your GPS and mark your parking place. You now want to walk about 5km to the East... That will put you in the center of the impact structure. Take enough water and a snack! Long pants for the spinefex bushes, and good boots.

The structure is in pastoral land, so you have a chance of meeting up with cattle, as well as a species or two of kangaroo/wallaby... The first part of the walk is through a level area crossed by a dried streambed or two. Then you will cross a hill range. This represents (depending on your interpretation of the structure) the remanants of the crater rim, central uplift, or... Notice the orientation of the rock. Occasionally chaotic, occasionally showing uplift. It is an old structure, and the impact may have been in shallow water. The central portion of the structure is relatively flat, and an occasional vehicle track goes across.

The exciting part:

As we were returning to the vehicle, we saw someone nearby. A security person from the mine, who then declared we were in big trouble as we had been trespassing. She called her supervisor who showed up soon after we drove back to the gate. She kept insisting we were in the wrong place, we asserted we were pretty sure we were in an allowed location... Fortunately for all, her supervisor arrived, and after a short discussion, we straightened out a) where we had been, and b) that it was perfectly fine to be there. She had been misinformed by one person, and to make things more confusing, had (mis)reported us as being in a place where we really should not have been. (near some off limits cultural areas, And, right near the active pit) In any case, we had an exciting 10-15 minutes getting everything straightened out.

If you go, you might phone the mine, just to let them know you know where you are going and for them not to be too excited.  

2009 update - I was back at Adel's Grove this July - I didn't get out to the crater on foot this time, but by a bit of randomness, I was invited for a quick checkout flight in a light plane - no time to grab a camera, but we flew over to the crater and mine area. A lot easier to see the topography, and it was late afternoon, for better shadows. Alas, maybe I'll be able to get up again next trip and take pictures.
I got to spent a day working with the paleos (aussie for paleontologists) at the Riversleigh dig - which was a lot of fun, if hot!!!

Here we are setting off  Setting off - setting GPS
I'm on the right - Peter on the left - image by Allan O'Neil


For a recent article - this is excellent:

Australian Journal of Earth Sciences - (2008)  55, (587-603)
New insights into the size and timing of the Lawn Hill impact structure: relationship to the Century Zn - Pb deposit
J. A. Salisbury; A. G. Tomkins; B. F. Schaefer

all from: School of Geosciences, Monash University, Vic, Australia


abstract:
URL: http://dx.doi.org/10.1080/08120090801888677





Panorama of the inner region of the Lawn Hill Impact Structure - taken from the western rim. Image center is the approximate center of the structure - the light "hills" to the right are the mine tailings of the Century Mine.

Panorama of the center of LHIS





The view back towares the previous hill from near the center of the structure - behind or just to the left of the tree in the middle of the image above. The image above was taken from part way up the higher rise on the left half.

Near the center



The view from Above
Lawn Hill Impact Structure from Above
Yes, this has been a bit stretched - if you want the original version Click And an image of The Mine



Extracted from a "low res" geological map of the area. Lawn Hill Impact Structure in the middle, the Mine is stated to be the Silver King Mine - It's changed it's name since the map was made. I'll see if I can pick up the more recent and higher resolution map when I get back this "summer"

Geological Map of area (large scale)

Page updated 2-Aug-2009