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Finding Chert in the Bathurst region

hgoat

Russell Coight
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From what I understand, chert is a worthy analogue of flint when it comes to knappable rocks. So what I did was bring up a geological map of my region (near Bathurst) and there was a significant length of "dark grey to black chert" running through it. Here is the map http://www.resourcesandenergy.nsw.g...0K_Geological_Sheet_8831_1st_edition_1997.jpg

And if you want to search your area the NSW maps are here http://www.resourcesandenergy.nsw.g...ducts-and-data/maps/geological-maps/1-100-000

The problem is I have no idea on how to read a map to get its coordinates. If I look at the map I see the Great Western Highway running east from Bathurst and hitting a chert formation (the light pink with vertical purple lines). How do I read this map to get the coordinates for where the highway and chert meet? Something I can throw in a GPS so I know where to look.
 

Aussie123

Never Alone In The Bush
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Ahh I found the google maps overlay that makes things much easier, http://gmaps.geoscience.nsw.gov.au/100K/Bathurst/ So I can see its at napoleon reef which I can just plug into google maps on my phone and take me right there. Does anyone have experience with this black chert?

I don't know your local chert, but the description is "Dark grey to black chert thinly bedded in crystal tuff ....."

I'd be looking for a road cutting, creek wall or outcropping rocks which will hopefully expose those thinly bedded cherts.

Creeks are a natural collecting point for rock and minerals, so scouring the banks can be useful. The rocks may not look quite what you expect, do an image search for black chert and ignore the really nice pictures !

You may be looking for something a bit like this "random" internet picture (no affiliation) :
https://www.flickr.com/photos/jsjgeology/15606612987

... but I'm just guessing (I know that's fossiliferous from the US, but it may be the sort of thing you will see). The fact its mixed with tuff and sediment may make it look a bit "speckled"
 

Askew

John McDouall Stuart
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I don't know about the Bathurst area, but there was a chert mining operation near Mt Victoria, the mine itself was in the kanimbla valley. Not sure exactly where though. There is a book about it by one of the local historians that I keep meaning to pick up one day. Chert/mudstone can he found in the megalong valley too, the Gundungarra people collected stone for tools here.
 

Le Loup

Rüdiger Nehberg
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There are a variety of siliceous rocks found in Australia, though not all are any good for knapping. The Quartz found here for instance is full of fracture lines. All are good however for use in flint & steel fire lighting, or for using as gun flints in a flintlock gun, rifle or pistol.
More information on my blog here: http://woodsrunnersdiary.blogspot.com.au/2010/07/flint-occurs-naturally-in-australia.html

And here: http://woodsrunnersdiary.blogspot.com.au/2011/05/girty-found-flint-at-hanging-rock-in.html

Keith.
 

sokorny

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In regards to your original post regarding reading the map. The map has two grid systems on it (1. UTM (latitutde and longitudes), and 2. Australian Map Grid (AMG66)

The UTM is the 33o00' and 149o30' numbers (in the top left corner). The map then shows intervals of 10 minutes. So you could plug those numbers into Google Earth / Map to find your location. I think Google requires it in decimal degrees though, so instead of 149o30' you'd put in 149.5 (30/60 converts minutes to decimal) and put either an S after the 33 or make it -33 (otherwise will take you to the northern hemisphere). Note is says that the datum moves 2'4' east year (so the locations could be a few km off nowadays ... around 40 minutes).

The main grid the map uses is AMG(66), which is now outdated (AMG66->AMG84->GDA94->GDA2020) ... most GPS will have WGS84 available for use (which is close enough to AMG66 for the purpose of this exercise). The map says that each of the grey lined grid is 1km intervals. The faint grey number 7 33 000 m E and 62 91 000m N (bottom left corner of map) are the starting points for the grid. Each grid the numbers increase eg. next corner is 7 34 000 E 62 92 0000 N.

I'd probably use the UTM to navigate and then use bearings/angles and distances to find the location (if they didn't have a dataset you could overlay in Google Earth that is :)

Clear as mud??
 
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sokorny

Russell Coight
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I don't know your local chert, but the description is "Dark grey to black chert thinly bedded in crystal tuff ....."

I'd be looking for a road cutting, creek wall or outcropping rocks which will hopefully expose those thinly bedded cherts.

Creeks are a natural collecting point for rock and minerals, so scouring the banks can be useful. The rocks may not look quite what you expect, do an image search for black chert and ignore the really nice pictures !

You may be looking for something a bit like this "random" internet picture (no affiliation) :
https://www.flickr.com/photos/jsjgeology/15606612987

... but I'm just guessing (I know that's fossiliferous from the US, but it may be the sort of thing you will see). The fact its mixed with tuff and sediment may make it look a bit "speckled"

Very good post and ideas for easy access to rocks. I studied a few units of geology at university and the lecturers loved road cuttings for showing rock formations / profiles.
 
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