Any generous geologists here?

[GaryE]

I've been digging online (pun intended) trying to understand my local shale (Saint John New Brunswick) deposits, a dark grey common shale deemed low quality for industrial exploitation in the pre-shale gas era. I just encounter either paywalls on papers, or my own ignorance as a person who didn't even take high school chemistry.

It may be an idle pursuit as the shale seems very hard and would make excellent aquarium decor. I can find varied info on chemically different forms of shale, but enquiring minds want to know.

 

[CassCats]

As far as I am aware, shale is a clay based rock, therefore should be inert, in all forms.

 

[anewbie]

As far as I am aware, shale is a clay based rock, therefore should be inert, in all forms.

It can have impurities in it - i know around here a white streak is calcium but there are other minerals that can be mixed in it depending on a number of factors.

 

[anewbie]

What you can probably do is put it in a pail for a week or three and see if the ec changes. Of course there will be a slight change since plastic pails leach but if you have a glass pail then it won't change if it is totally inert.

 

[GaryE]

It's been good in the past. It's hard shale, difficult to break. Uniform dark colour, which I like in sedimentary rock. I'm sure a pro can get the info fast, but I get bogged down in the greed guys.

 

[TwoTankAmin]

Have a read here. I am not sure if this is the sort of info you want.
New Brunswick Shale Gas Air Monitoring Study – Synopsis
or this may help as well
Industrial Minerals Summary Data- County: Saint John

 

[GaryE]

Thanks @TwoTankAmin . I'd already found those, but we're getting closer.

I'm trying a piece in water, as I did 2 or 3 years ago.

I've seen shale take a few forms, from soft to this stuff. Back in the 1800s, a geologist classified the local vein as slate, but it doesn't break that way. I'm not trained to know the dividing lines, though I looked it up on a geology for curious kids site.

Ten minutes from here, I could pick up literal tons of it, all broken by construction and just lying there. Costco and Home Depot have large stores on a hill formed of it, and the dynamiting to flatten it was pretty extensive. If it's inert, it would make for a couple of really nice Congo River set ups.

 

[WhistlingBadger]

Get in touch with your local (or close to local) university geology department. In my experience college professors in rather esoteric areas are generally quite happy to help with things like this. I think it makes them happy that someone in the real world is actually interested in what they do. I've had fun conversations with university specialists in microsnails, bryophytes, and euphonium literature...

 

[Uberhoust]

Shale is a really interesting rock with lots of variability. As other have mentioned it is often made-up clay and clay minerals, which can be a problem. Clay minerals can expand with contact with water breaking the rock down over time and releasing clay minerals into the water resulting in somewhat murky water. Additionally, some shales are cemented by calcium, magnesium, and sodium salts which can overwhelm your water chemistry. Finally, they often have a bit of an organic component, with iron being commonly present. The result is you need to be careful with shale. Shale is lithified (made into rock) only by compression and cementation, slate is metamorphosed into different compounds and is less likely to break down in water (except slates with high amounts of pyrite)

That said if it is hard enough it is worth putting into an unused tank or bucket with water for a bit an assess if it is breaking down in the water or releasing too many undesirable chemicals into the water. I have used shale in my tanks but only shale that was close to being classified as slate.

New Brunswick has some geological information available.
https://open.canada.ca/data/en/dataset/f1f16e7d-a959-fe16-2857-361268ca1acb - OK if you can read the metadata and the data, likely you will need some programming skills.

https://www2.gnb.ca/content/gnb/en/...nt/minerals/content/SurficialGeologyMaps.html - This site was not working correctly for me but looks like only the federal data is available. Supposidely, maps are available.

https://hub.arcgis.com/datasets/NBDNR::nb-bedrock-geology/about - Finally a GIS system but unfortunately was only able to discover the formation names but little details. Gives at least some of the surface geological data.

Overall, just like you have found, there is information but unlike BC where I live New Brunswick doesn't have a central location with geology information associated with GIS mapping. I would try a soak test, to see if the rock breaks down, and a carbonate test with acid. If it passes both of those it is "likely" OK.

 

[TwoTankAmin]

Here is what I do know. We have a stone and gravel yard locally. It is where many of my tanks' rocks originate. I get two types of rocks from them. The first are the bigger sized river rounds pictured below:

The second are pieces of the flagstones:

Flagstone is a type of sedimentary rock characterized by its flat, layered, and slab-like appearance. It is primarily composed of minerals like silica, calcite, and iron oxide, formed by the hardening of sediment layers over millions of years. Common types include sandstone, slate, and limestone, frequently used for paving, patios, and walkways.

The ones I use are a darkish gray. In the stone yard they have a section with these. they are about 2 -2.5 foot squares about an inch thick. That is not what I want. What I do is to search the area where they have them stored on edge for pieces that have been sheered or broken off. The come in all shapes ad thicknesses. You can see an assortment of such pieces in the two pics below:

I have had these pieces in some tanks for over 20 years to no ill effect. This includes all of my pleco breeding and grow tanks.

(edited to fix typos)

 

[GaryE]

I can walk across the road and haul rounded rocks back easily. I've established a fair number of the local sea rounded rocks are inert, and they feature in my set ups. I have a kilometer of rocky beach stretching out down there. Some mornings before things get active on the road, I can hear rocks rolling in and polishing each other in the surf as they escape from the depths.

The advantage to the shale/slate is its shape- mostly flattened. It's very good for cave spawning Cichlids who want to dig out their spaces. I imagine you could also create some good mbuna set ups too, if I kept those fish. I guess I could get some slate tile samples and whack them with a hammer, but I think the local stuff could be good. Tests to follow...

I'm not well set up for wood, as these are pinelands, with resins I don't want in the tanks. My neighbour has an elm - a huge hardwood that somehow dodged disease. It's lost a long branch over the winter and I may set to work on prepping some of that this summer. It takes time to sink it. I've planted some native red oaks, a species very badly thinned by the monoculture in pines favoured by our local forestry corporation. But they won't be large anytime soon.

When I get out kayaking, there's a maple lined river nearby where I can get winter debris pieces that I can probably work with.

I've still never bought rocks or driftwood...

 

[Back in the fold]

All rock is interesting and it’s so varied in its forms . I’ve always kept my eyes on the ground looking for interesting rocks . Lately I find an old unexplored interest of mine occupying more of my thoughts . I’m thinking about buying a rock tumbler to polish up some of the nicer ones I’ve found . There are lots of books out there on rocks and crystals that are very fascinating . This is a whole hobby in itself .

 

[GaryE]

You want a rock tumbler? Come visit the Bay of Fundy!

 

[Back in the fold]

You want a rock tumbler? Come visit the Bay of Fundy!

With the huge volume of water that swooshes in and out of that Bay that’s a good description of it . I’m curious , can you hear the water moving ?

 

[TwoTankAmin]

I just buy my wood. Most of it has been Malaysian, it sinks when it is dry. But early on I used get cyoprus from swampwiz, That did not sink and mossy of it I anchored using tile nylon spaces and SS screws. I could bury the tile under the substrate and that held it down until it water logged