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Saturday, 3 December 2011

Bluestone Rock Types



About a year ago I published this updated list of the 31 or so different "bluestone" rock types that are now recognized in the Stonehenge area.  Thanks to Rob Ixer and Richard Bevins and their collaborators, the geology is moving on apace, and this list probably now needs revision -- especially in the light of the work relating to Pont Saeson / Craig Rhosyfelin.  All comments gratefully received on the accuracy of this list, and corrections that need to be made.  I'll do my best to keep this list as authoritative as possible.......

Stonehenge Bluestone Types

1.  Unspotted dolerite ---- monoliths  45 and 62.  Carn Ddafad-las?

2,  Spotted dolerite -- densely spotted.  Monolith 42  -- Carnbreseb? 43?

3.  Boles Barrow dolerite -- spotted?  But similar to stones 44 and 45? From Carnmeini / Carngyfrwy area?

4.  Rhyolite  -- stones 38, 40, ignimbrite character.  Ash-flow tuffs (dacitic). Not Carnalw ? May be from different sources?

5.  Rhyolite --  stones 46 and 48, rhyolitic ash-flow tuffs.  Carnalw area?  Same source?

6.  Rhyolite fragment from a different source from the above types

7.  Laminated calcareous ash -- stumps 40c, 33f,  41d

8.  Altered volcanic ash -- stump 32c, 33e?

9.  Rhyolite -- another type -- stump 32e.  Related to Pont Saeson samples?

10.  Micaceous sandstone -- stumps 42c, 40g (Palaeozoic -- South Wales origin?)

11.  Rhyolite -- lava -- stone 46

12.  Rhyolite -- flinty blue -- different lava?  stone 48

13.  Spotted dolerite with whitish spots --stones 33, 65, 68, stump 70a?, stump 71?, 72

14.  Spotted dolerite with few spots -- stone 31, 66?

15.  Spotted dolerite with pinkish spots -- stones 150, 32, 34, 35A, 35B (one stone), 39 (?), 47, 49, 64, 67, 69, 70

16. Spotted dolerite -- moderate spots -- stone 37, 61, 61a?

17.  Unspotted dolerite -- stone 44 -- different from stones 45 and 62

18.  Very fine-grained unspotted dolerite -- stone 62

19.  Silurian sandstone -- Cursus -- fragments

20.  Devonian sandstone -- Altar Stone -- Devonian Senni Beds -- Carmarthenshire or Powys

21.  Sarsen sandstones -- various types -- packing stones and mauls

22.  Jurassic oolitic ragstone -- Chilmark?

23.  Jurassic glauconitic sandstone -- Upper Greensand?

24.  Gritstone unspecified fragments (Maskelyne, Judd)

25.  Quartzite unspecified fragments (Maskelyne, Judd)

26.  Greywacke unspecified fragments (Maskelyne, Judd)

27.  Granidiorite -- Amesbury long barrow 39

28.  Quartz diorite -- ditto

29.  Hornblende diorite -- ditto

30  Flinty rhyolite -- fragments from Pont Saeson

31.  Rhyolite fragments -- with titanite-albite intergrowths (source unknown)

19 comments:

Alex Gee said...

Could the source of the volcanic ash and rhyolite tuffs, be the volcanic outcrops on Beacon Hill in the Mendips? has any work been done on this?

Anonymous said...

No, yes
Read the primary literature and save us all time.
I am so fed-up with saying that
Thorpe et al 1991 is the obvious place to start.
Speedy

Alex Gee said...

Non academics don't have access to all of the primary sources; not without spending £30 a pop.

Thanks anyway

Anonymous said...

I too do not have access to free libraries (I could not get my electonic pass to work). I email the authors and ask for copies.
((Many papers are now freely available on line-many of mine are(the ferret club, MUCH of the primary literature, is for example)).
Use lots of soft soap, show you have researched them and their work, complement them on their choice of domestic pet, send flowers (chocolate gingers -big box -always work for me)and it works if you need a hard copy.
Try scirus for example to get the literature.
Anyway £30 is cheap for enlightenment- Self-awareness courses are £100s
There is more to useful research than just putting a word into Google/Facebook and becoming discouraged when trivia is returned.
Myris

Tony H said...

Unfortunately, in these times of recession, the Somerset public libraries (which I think is where you live, Alex) may not be purchasing volumes such as the Thorpe one Speedy mentions. But it might be worth asking if they have it (or similar) SOMEWHERE amongst all their libraries in Somerset, including the HQ Local History library. In which case, the volume you required could be sent to your nearest library for you to either read there, or borrow.

The full references for many such sources are listed in the back of Brian's 'Bluestone Enigma'. Good luck.

BRIAN JOHN said...

I have found that a direct approach to the author often works best. Most of them have PDF's of all their articles on tap, and are only too happy to send them out when nicely asked. No flowers or chocolates needed -- simply being asked gives them a rosy glow.

Anonymous said...

Speak for yourself I demand flowers, chocolates and the most grotesque flattery.
Rosy glows I can get from standing close to burning Libraries.
Yes pdfs mean that almost everything is now available from authors. A hint try the second/third author they will be far more eager plus you make a friend for life.
And the author receives none of that £30 as I point out often and forcefully to the British library and that one at Boston Spa when they want to charge me for my own papers.
Myris of Alex etc.

Anonymous said...

Using soft soap, Myris, can have unfortunate side-effects: several authors have been reported (in the NON-tabloid press too) to have come up in quite an unintentional lather as a consequence.

One of my Yorkshire Grannie's (RIP) frequent expressions was that it was funny how such-and-such, although covered in horse sh##, came up smelling of roses. In later years I realised the deep profundity in her turn-of-phrase, as well as its horticultural applications.

Flattery always works a treat both for, and on me, sentimental fool that I am, and I always sign copies of my books when asked.

A Titch-Marsh, Ilkley Moor

Anonymous said...

Those of us who were in the Los Angeles/ San Francisco area in the late '50s remember Rosy Glow as a great night-club "torch" singer. Don't believe what you may have heard about Rosy in the tabloids - she was a good-natured girl with deep moral values. And she never let the punters stand too close to her as Myris seems to think. She was too much of a Lady.

"PEACHES" DUPREE

Anonymous said...

While we're on the subject of how to procure PDF'S from writers (which we still are, dear reader!), many's the esoteric author I've plied with Blossom Dearie (1924-2009) records, to great effect. Peggy Lee was never the way to a geologist's rock-hard heart........but Blossom always was.

Lord Bragge

Anonymous said...

I have always called Blossom Dearie 'crystallised petals of Peggy Lee'.
They COULD sing. The Gods they could sing!!
For a Blossom Dearie record you can have copies of all my publications books/CDs, all signed and with chocolate kisses and possibly..... more.
I could tell you stories of me and Rosie aka Razamataz Hotmama but my wife would slay me.
Myron of Height Ashbury

Anonymous said...

Lordy Lordy Miss Peaches where's my manners. You seems like a fine well brought-up young lady. Are you one of the Alabama Duprees? I am related, albeit too distantly, to the Tennessee Ravenals.
Simon PO BOX 10 Baton Rouge.

Anonymous said...

SIMON

I am fascinated, and probably could become entranced, by your 10 Batons Rouges! Come up and see me some time, you'll be mighty welcome, and I'll leave my Zip Code for you alone, at reception....

PEACHES

BRIAN JOHN said...

What is this, a Stonehenge discussion blog, or a dating agency? Well, I'll do what I can to make people happy, as long as it's legal....

Anonymous said...

Talking of Blossom Dearie, whilst I was casually glancing at Brian's favourite "One Show" tonight over my TV dinner, expecting to savour at least another apoplectic tirade from that nice 'mobile' young man who seems to have upset half the Nation recently, when who should appear but America's modern singer-songwriter sweetheart, Carole King? Is it me, or hasn't she inherited the crown Blossom left? And, she lives out in the Heartland of America, a real country person.

Bragge

Anonymous said...

One of my favourite bands was Jo-Mama -for the two years they were together. "J is for Jump"- all part of the King-Taylor stable.
Lady 1960/70s singer-songwriters were always a favourite (so much so I married one)and Ms King is up there with the greats.
Hissing Summer Lawns.
My but we have come a long aways from the "boring old stones in the south of England" recently overheard said by the great and the good in high powered London alleyways!

Geo Cur said...

"My but we have come a long aways from the "boring old stones in the south of England" recently overheard said by the great and the good in high powered London alleyways!"

Maybe not .There is a flimsy but very funny connection between SH and Jo Mama .

Anonymous said...

Go on I must know.

BRIAN JOHN said...

This doesn't seem to me to have much to do with bluestone rock types. Can I gently suggest a continuation on those learned sites called Twitter and Facebook?