Central Australia - Arthur Creek Formation

[JesseKoz]

I have just returned from my first visit to a new fossil locality in the Northern Territory, central Australia. The location is around 400km north-east of Alice Springs along some rough dirt roads and once reached, runs for about 10km along the side of the road. When visiting the location today one finds themselves in the very center of Australia and a landscape of flat desert and scrub land, about as far from the sea as possible. In the middle Cambrian the site was very different and home to a vast shallow sea filled with ancient life.

 

Arriving in the late afternoon we set up camp and got prepared for the morning of fossil hunting ahead. I had read about the fossil location from a small local out of print fossicking guide from the 1980's. That lead me to read some of the work done by John R. Laurie who has some papers published online detailing the formation and it's biostratigraphy. We managed to find some good examples of Xystridurid trilobites and stromatolites, all found within a red/white siltstone. There were also a smaller species of Agnostid trilobite, but we found many less of these. Below are some quick images I took of some of the finds, many more yet to properly examine. Also we have some larger slabs of siltstone which we plan to work on.

 

Trip Image Album:

 

The fossil site is found in the location below

https://www.google.com/maps/place/21%C2%B042'53.0%22S+135%C2%B039'38.9%22E/@-21.71473,135.66081,1873m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d-21.71473!4d135.66081

 

In the publication below, NTGS Elk 3 bore samples refer to the location visited.

 

Quote

 

Biostratigraphy of the Arthur Creek Formation and Thorntonia Limestone, Georgina Basin

by John R. Laurie

https://www.researchgate.net/publication/236858748_Biostratigraphy_of_the_Arthur_Creek_Formation_and_Thorntonia_Limestone_Georgina_Basin

 

NTGS Elk 3

Arthur Creek Formation

6.80-9.60 m: Xystridura altera (Templetonian)

57.15 m: Pentagnostus rectus (Templetonian P. shergoldi Zone)

64.85-65.12 m (Shergold sample): Pentagnostus shergoldi

(Templetonian P. shergoldi Zone)

66.87-85.13 m: Pentagnostus praecurrens (Templetonian P.

praecurrens Zone)

99.20-99.27 m: Pentagnostus anabarensis (Templetonian P.

anabarensis Zone)

 

 

 

Great trip! Very pleased with the finds and learning more about the geological history of central Australia.

 

[Guest]

Nice finds! Hoping to get out to that area some day. 

[Wrangellian]

How big are the fossils? Your photo could use something for scale...

And is that a stromatolite in the lower right?

[JesseKoz]

19 minutes ago, Wrangellian said:

How big are the fossils? Your photo could use something for scale...

And is that a stromatolite in the lower right?

Here is a quick image with some measurements added. I'll repost in this thread with some more detailed photos of each fossil with a ruler in shot. The two fossils on the right-hand side are what I believed to be stromatolites, but I'm still an amateur so any clarification on their identity would be great once I have some better photos. According to the information I've read, the Xystridura trilobites found in this location can read a length of 7cm.

 

Edit: the fossil in the top-left hand corner in the image below is the same fossil seen in the close-up shot in my first post.

[Monica]

Beautiful finds in a beautifully remote place - thanks for sharing! 

 

By the way - did you see any interesting living critters while camping there?

[JesseKoz]

It has been quite dry here recently, no sign of kangaroo's or other larger animals, as they're most likely hiding out near the water holes. We did see a lot of birds though, large flocks of budgerigars (those same ones popular as pets, but wild this time), some wedge-tailed eagles and evidence of where a group of Australian bustard's had met untimely ends after being hunted by the local Aboriginal people. They call them bush turkey's and are quite popular eating, you can sometimes find the large piles of feathers left behind.

[RJB]

Are these surface collected or did you dig in the actual formation?  Cool pieces though.

 

RB

[JesseKoz]

12 hours ago, RJB said:

Are these surface collected or did you dig in the actual formation?  Cool pieces though.

 

RB

Hi RB,

 

All my finds were collected from the surface or the occasional few from the heaps of rock pushed aside when the road was graded. From the reports of the area I have read the fossiliferous layers of the Arthur Creek formation continue to a depth of 100m. Most of my best finds were from the locations where the natural rock formation was exposed. The location continues for a whole 10km along the road, with the tops of multiple ridge dissecting the road and fossils being found along the tops of these ridges.  

[piranha]

Here is the classic monograph:

 

Öpik, A.A. 1975
Templetonian and Ordian Xystridurid Trilobites of Australia. 
Australia Bureau of Mineral Resources, Geology and Geophysics Bulletin, 121:1-84  PDF LINK

[JesseKoz]

37 minutes ago, piranha said:

Here is the classic monograph:

 

Öpik, A.A. 1975
Templetonian and Ordian Xystridurid Trilobites of Australia. 
Australia Bureau of Mineral Resources, Geology and Geophysics Bulletin, 121:1-84  PDF LINK

Thank you piranha! This is exactly what I've been wanting to find.

[JesseKoz]

Geological map of the fossil locality:


Core sample location is noted on the map, as well as known locations of fossils and trace fossils. This map proved very helpful when working out the best location to search.