Rock Nerd Needed..

[Matt The Magic Man]

Hi Guys,

I'm hoping someone may know their rocks well enough to be able to tell me what type of rock this is?

The 'moss' growing on them is all of the rock that is exposed & most of the time they are buried vertically with many pieces butted up hard against each other..

They are cropped up over the property in North to South runs:

I know there is Slate in the area, but not sure if that is what my rocks are..

If it helps the area is South West Tablelands of NSW, Approx 600m above sea level, has some quartz also & the the wider area used to be mined for Tin.

Thanks in Advance, Matt.

 

[shivan]

I still have my training wheels on when it comes to identifying rocks. Any chance of a close up?
The first two photos look like some sort of felsic sedimentary rock where as the third photo they seem a bit more reddish/earthy.
If there is slate in the area maybe a mud/silt stone?

 

[Matt The Magic Man]

Thanks Shivan.. I wrote Slate, but I meant Shale. I believe the two are closely related anyway..
Is zooming in on the 1st/2nd picture sufficient for what you want to see, or are we talking Macro level granular shots?

Cheers, Matt.

 

[shivan]

Yea, was more wondering if there were grains or crystals visable. The first two photos look a bit like a quartz sandstone, i may be off the mark but would make a bit of sense if if is a bit more resistant to erosion than the rock around it.
I believe shale is a type of mudstone that easily splits into thin layers, slate can form from shale or other mud/siltstonethat has been metamorphosed till the minerals are foliated and show "slaty" cleavage.
If tin was mined in the area keep an eye out for cassiterite along quartz veins.

Hopefully someone else will have a better idea

 

[Matt The Magic Man]

Some more looks at the rock, hopefully helps to identify it:

See how pieces of it flake off along some sort of 'fault' lines..

This rock shows layers within some of the rock:

More of how the rock crops out of the ground:

You can see how high the mountain goes up, it's the same as this for 100m below & all the way to the top (more or less)

 

[Heatho]

What are hunting Matt, anything in particular? How's things?

 

[Matt The Magic Man]

Hi Heatho, things are good mate. Not out hunting at the moment, bit of gold maybe.. Hehe

These rocks are a side project. I'm doing a Gabion wall & since these are the rocks I'm using I thought I would try to find out what they actually are.

How's things with u? Popped that nugget cherry yet?

 

[Heatho]

G'day mate, I did pop that nugget cherry, felt good too and it was only 0.1, got a few more little ones also.

The wall should look nice with those rocks, will last forever too.

If you're keen to catch up sometime just gimmee a shout.

All the best.

 

[richo966]

I found the same type of rock when digging sewer mains it ran shale then this type of rock in a straight lines the rock come to the surface small at the bottom then larger as it came to the surface the formation repeated every 3 meters one operator said it was cist not sure what that is but it stopped the 20 ton machine cold hard rock no one had seen it before like this in straight lines among the shale and there was a lot of experience on site rain run of from this site feeds a creek that has gold looking at the rock it looked like it was formed by hot liquid coming up from below another old operator agreed that it looked volcanic in the way it was deposited I wish I had time for good pics I could not get any light under ground I think very interesting find worth looking into this find I am keen to hear how you go I will take some pics of the rock still above ground and try and post them

 

[Matt The Magic Man]

Thanks Richo that would be good.

I get the 'feel' it's volcanic in the way the mountain has been pushed up but that may have happened from below once the rock had already formed..

Picture number 3 in my last post shows it to be pretty sedimentary. I've looked at Schist as the rock as it's closely related to Shale & Slate. As I said though, I'm not 100% & hoping somewhere here is..

 

[SWright]

G'day all

It is always hard to tell out of context, but my guess would be a silty slate - that is a siltstone that has been metamorphosed and as the fabric is not strong and you said that there is tin nearby (generally only in granite) I would suggest that it was due to contact metamorphism of the shale and siltstone near to the granite contact. That is called a hornfels and it does not generally form a strong fabric or parting in the rock like a slate or a schist. Both Slate and Schist form from what is called regional metamorphism where the rock has been subject to strong deformation doe to pressure as well as heat. A schist will have an almost silvery sheen like a fish.

Araluen

 

[RedDirtDigger]

I,m with Araluen its definitely a clay/silt rich rock that has been metamorphosed by pressure and a little heat. The outcrop and fracture pattern of the rock indicates that the thin bed is dipping near vertical and has been through the pressure mill and intense folding that is common in the Lachlan Fold Belt. The beds you see sticking up are slightly tougher and erosion resistant compared to the adjacent beds and hence they stick up.
RDD

 

[richo966]

Very hard rock lost my phone down the sewer drain but I still have a sample if any one is after a look

 

[Nightjar]

Phone wouldn't be very pretty after going down the dunny. 8)
Pass on that one.

 

[richo966]

no I have rock samples and if there is gold in it there is a massive pile of the stuff free for the taking I just need some one with dolly pot and I will bring the rock samples