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Carboniferous Corals From The Uk


TqB

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Having said a couple of posts ago that I don't find Palastraea regia in my area, I was astonished when this specimen of it turned up recently.

 

It's from the basal Namurian Great Limestone (that's upper Mississippian), found in weathered quarry spoil. As far as I know (and having checked with a specialist), it's a first record from this bed. 

It's fairly common in some other parts of the UK but a few cyclothems down.

 

The voids between the calcite walls are filled with silica so there's an attractive negative weathering effect.

 

Weardale, County Durham.

 

58a3586600267_IMG_2209(3).thumb.jpg.010d91e6f8d74aaf6a48bdb9f7f0d487.jpg

 

58a3586bde0c6_IMG_2209(2).thumb.jpg.fb4aef0b189088e45af5662ce289f78a.jpg

 

 

vertical section:

58a3587087b33_IMG_2212(1).thumb.jpg.7475b3f38963b7e4b180f128f060c73e.jpg

 

 

 

 

 

 

 

  • I found this Informative 2

Tarquin

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  • 2 weeks later...
  • 3 months later...

For the Collections section, I have just rephotographed this specimen from my first post here, using a better camera setup.

The 3D detail of the structure visible through the clear calcite fill is rather pleasing.

 

Actinocyathus floriformis (or possibly laticlavia - a larger corallite that may be the same species anyway). Namurian, Pendleian Stage, Great Limestone, Northumberland.IMG_2496.thumb.jpg.b038158f8cf076266bd29f11aa0010e8.jpg593a95f01f3da_IMG_2496(1).thumb.jpg.6fc67329184a4b4d162f5679ac7baf38.jpg593a95f832a55_IMG_2496(2).thumb.jpg.770e5f6faffe9572e701f5a243dbc3e2.jpgIMG_2488.thumb.jpg.2c8fc451d4e6465549c4043b86701904.jpgIMG_2492.thumb.jpg.92c5e460459c39adf5e57b973c176fe5.jpg,

 

 

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Tarquin

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Once again you've made it painfully obvious that you don't know the first thing about photographing fossil corals by inflicting more of these 

Rohrschachy shapeless blobs upon us poor hapless TFF members.I've seen more detail in a can of black paint hidden underneath a black tarpaulin

at the bottom of a coal mine while wearing sunglasses.At midnight.

Hideous!

So ,what's Ian like?;)

 

 

 

 

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Sweet corals. The ones you showed are at a different level from the ones I collect here in my area locally.

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  • 1 month later...

Thanks, @JUAN EMMANUEL - sorry, missed your comment!

 

Same species as the last one but another locality and preservation.

Found recently and cut today.

 

Actinocyathus floriformis, , Pendleian Stage, Great Limestone, County Durham.

Brass scale bar 1cm.

 

.IMG_2551.thumb.jpg.670658dfeb282d2ebd2f08fc2e0b092b.jpg

 

IMG_2552.thumb.jpg.d85efacd42d009588b9b2181d80af0d3.jpgIMG_2553.thumb.jpg.14253aab4e60bcccad1d69cd9ee0450b.jpg

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Tarquin

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  • 2 weeks later...

yep amazing material/collection. Congrats. 

 

Thanks for all the neat photos. Regards, Chris 

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Just enjoyed this post in it's entirety. Can you walk us through how you cut and polish these. I have collected enough corals to begin to "sacrifice" some in order to expose their inner beauty.

 

 Mike

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@Plantguy & @minnbuckeye.

 

Thanks for the comments!

 

Mike - the process is simple. I use a 14" rock saw (diamond blade, water lubricated) to cut the pieces, then grind with successive grits of wet and dry paper (used wet) laid flat on a glass sheet. The glass sheet has another piece of wet & dry (150) glued to the upper surface to stop things sliding around.

 

A typical sequence of grits would be 150 - 240 - 400 - 600 - 800 - 1200.

After 800 or 1200, the surface is good enough to photograph just covered with water in a bowl. This looks a lot better than  a dry, polished surface and the slightly matt finish stops the thin water layer from clumping up.

 

If I want a display polish, I use a 10" cloth buffing wheel (mounted in a lathe) with a polishing compound (for stainless steel I think but I got it from my prep tools maker). Otherwise, I've used cerium oxide paste on a sheet of hard leather - a wheel is a lot easier though for a large slice.

 

 

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Tarquin

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5 hours ago, TqB said:

Mike - the process is simple. I use a 14" rock saw (diamond blade, water lubricated) to cut the pieces, then grind with successive grits of wet and dry paper (used wet) laid flat on a glass sheet. The glass sheet has another piece of wet & dry (150) glued to the upper surface to stop things sliding around.

 

 

Thanks so much for the insight. I have all of those tools. Glad an expensive piece of equipment was not needed.  Will make it a winter "chore" in a few months.

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  • 2 months later...

Dibunophyllum bipartitum is an iconic solitary coral and is usually the most common species in my local Carboniferous limestone.

I've been looking for a while for a specimen showing this preservation, with clear calcite infill - most of them are rather granular looking.

This one is from a crinoidal layer where corals are rare and somewhat rolled but usually showing this detailed, 3D structure.

 

Four successive sections taken over about 3cm of it's length. The brass scale bar is 1cm long.

 

Photo 1 - typical of the species, with the strong central lamella dividing the axis in two.

IMG_2672.thumb.jpg.0c4a32c6be02caf5781e511f62fc4d6c.jpg

 

Photos 2 & 3 show the lamella breaking down - this is a variant that has been used as the basis of a subspecies, D. bipartitum konincki. The variation is continuous across the species though so is of limited use - specimens from one area or bed may tend to one or another:

IMG_2676.thumb.jpg.b55481dc30f002a1eb56abeb3519b753.jpgIMG_2679.thumb.jpg.6e98e543293ec539e591bcb8c895c058.jpg

 

Photo 4 is from just below the top of the sediment filled calice and shows the axial structure carrying into the central boss.

IMG_2681.thumb.jpg.26a60de3428fe6993afaa82f8650b6f0.jpg

 

 

 

 

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Tarquin

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Tarquin,

This is truly informative thread, and has opened my eyes to the beauty and mystery surrounding these creatures. 

Thanks for the ongoing lessons. 

Regards, 

    Tim    VETERAN SHALE SPLITTER

   MOTM.png.61350469b02f439fd4d5d77c2c69da85.png      PaleoPartner.png.30c01982e09b0cc0b7d9d6a7a21f56c6.png.a600039856933851eeea617ca3f2d15f.png     Postmaster1.jpg.900efa599049929531fa81981f028e24.jpg    VFOTM.png.f1b09c78bf88298b009b0da14ef44cf0.png  VFOTM APRIL - 2015  

__________________________________________________
"In every walk with nature one receives far more than he seeks."
John Muir ~ ~ ~ ~   ><))))( *>  About Me      

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Wow incredibly beautiful corals and really nice photos they are otherworldly. Very Nice Tarquin I am envious. 

Kind regards Bobby 

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I'm generally not a coral guy. But these are just absolutely beautiful.

Olof Moleman AKA Lord Trilobite

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I too agree with Ludwigia it is concisely , informative and enjoyable  post. But as an Artist i can't get over the refinement of the structures combined with the contrasting pigments makes them phenomenal  polished slices of rock. Next pay day I am looking around for some polished corals to add to my collection. Inspired.

 

Cheers Bobby

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