Now we receive absurd and inaccurate lessons in English Literature! Can we restrict postings on this site to science and omit the semantic pedantry. Blather is an appropriate word in this context.

Roger and all,

    The term ultramafic basalt is simply a tautology because a basalt is mafic but not ultramafic.  Who uses that term, anyway?  I commonly seen komatiitic basalt or basaltic komatiite, which is unfortunate because komatiite is an ultramafic rock with a certain texture.  Sometimes such terms are invented because the rock is close to a boundary with another name as if that in any way is surprising.  Basaltic andesite has since grown over time to have its own field.  If the komatiitic basalt has a komatiitic texture, that is logical, a basalt with komatiitic texture as opposed to one that has none.   It remains confusing chemically.  Igneous basalt is ridiculous because it is redundant, the first term in no way further constraining the second.  An olivine gabbro is not ultramafic unless it is a lherzolite.  The proper use of preceding adjectives and nouns in compound nouns is that they must further constrain the final noun, which is also your opinion I see.

    Moreover, no more than a total of three adjectives, adverbs or nouns should be used in a chain; otherwise it leads to great uncertainty as to what is modifying what.  I call the current fad of 4-6 such modifiers Bushtalk for two of our most favorite recent presidents.  One could say magnesian basalt or olivine basalt, but not ultramafic basalt or the redundancy mafic basalt, which in no way provides restricting information as you point out.  Next will we have mafic igneous plagioclase pyroxene basalt?   Scientists should use adjectives and adverbs sparsely and choose them well, like Hemingway, not blather on and on like George Elliot.

cheers,

eric

On Nov 27, 2009, at 8:44 AM, Musson, Roger M W wrote:

One could argue that adjectives play two roles in English. One is to distinguish nouns subject to the qualifying adjective from those not so qualified. Thus, "ultramafic basalts" are distinguished from other basalts that are not ultramafic. Under this interpretation, it would be absurd to write "igneous basalts", since there are no non-igneous basalts. However, it is quite common to find adjectives used merely as a way of expressing additional information about the noun. Thus, one could easily find someone writing "igneous basalts" to mean "basalts, which are igneous".

Personally, I don't like it, and I prefer to strike out any adjectives that are not essential. Don't get me started on "organic vegetables".

Roger Musson

-----Original Message-----

From: Tectonics & structural geology discussion list [mailto:GEO-

[log in to unmask]] On Behalf Of Eric Essene

Sent: 26 November 2009 18:51

To: [log in to unmask]

Subject: last comment

Tim and all,

    This is my last online response on this topic.

    Maybe 'igneous intrusion' is used much more in the UK than here.

If the terms  'sedimentary intrusion' and  'metamorphic intrusion' are

seldom used, why is the construct necessary?  Next will we use

"sedimentary granite" or "sedimentary limestone"?

    A problem can arise if we don't agree on the meaning of the words.

    Yes, indeed, I did not understand the meaning of this particular

notice that was just sent out by Rob and Zoe.  Maybe some other notice

was sent previously that was clearer.

cheers,

eric

On Nov 26, 2009, at 11:26 AM, Tim Needham wrote:

I'm not really sure why I'm replying to this but...

Dare we consider that, unthinkably, Georef isn't quite up to speed

on this?

The 'keyword' approach is often frustrating and not very helpful. I

suspect

that most geoscientists worth their salt(!) know what an 'igneous

intrusion'

or 'clastic intrusion' is. The main benefit of this thread has been

some of

the highly informative references on clastic intrusions (thanks in

particular to David Macdonald, Mads Huuse and Bob Holdsworth).

Basically, we

describe what we observe and go from there rather than try to

pigeonhole

into 'popular' terminology. Did anyone really misunderstand the

actual

conference announcement?

Cheers

Tim

-----Original Message-----

From: Tectonics & structural geology discussion list

[mailto:[log in to unmask]] On Behalf Of Eric Essene

Sent: 26 November 2009 15:48

To: [log in to unmask]

Subject: Re: Anderson Stress Meeting: September 2010 reminder

Carl,

  The term "sedimentary intrusion" has one citation in Georef.

cheers,

eric

On Nov 26, 2009, at 6:24 AM, Carl Stevenson wrote:

Hi all,

Sedimentary intrusions - does anyone know of any AMS (anisotropy of

magnetic susceptibility) work on these?

Desperately resisting getting drawn in to a semantic debate, I think

'igneous intrusion' is fine. I guess it is as opposed to igneous

extrusion - lavas and ash etc. Sometimes in when subvolcanic roots

are exposed it is actually equivocal. There are instances when ash

can fall back into a vent.

An example I am aware of is:

ALMOND, D. C. 1977. Sabaloka Igneous Complex, Sudan. Philosophical

Transactions of the Royal Society of London Series a - Mathematical

Physical and Engineering Sciences, 287, 595-633.

Cheers

Carl

-----Original Message-----

From: Tectonics & structural geology discussion list

[mailto:[log in to unmask]

] On Behalf Of Stu Clarke

Sent: 26 November 2009 10:23

To: [log in to unmask]

Subject: Re: Anderson Stress Meeting: September 2010 reminder

Don't you hate it when someone gets that email in just before

you......

I too have no particular stand on terminology, but I too was

surprised by

the stated scale of sedimentary intrusions. I have examined large

scale

sedimentary intrusions in deltaic settings and currently work with

colleagues using oil-industry datasets on the same thing. I don't

think

sedimentary intrusions have to be small scale......

Stu

-----Original Message-----

From: Tectonics & structural geology discussion list

[mailto:[log in to unmask]] On Behalf Of Macdonald,

Professor

David I. M.

Sent: 26 November 2009 10:11

To: [log in to unmask]

Subject: Re: Anderson Stress Meeting: September 2010 reminder

Dear Eric

I have no particular stand on the terminology for igneous rocks, but

you are

incorrect in your assertions on the scale of sedimentary

intrusions.  Salt

is a sedimentary rock which can be injected through kilometers of

strata in

bodies hundreds of metres to kilometers across.  Anyone who has ever

worked

on deltas can point to mud diapirism on a similar scale.  Even the

humble

sand injection feature is much larger than you make out; your

description

seems to be of sand filling pre-existing cracks, whereas most sand

injections are of a fluid slurry under pressure.  These intrusions

can be

huge.  In the Mesozoic forearc basin of the Antarctic Peninsula,

sandstone

dykes have been mapped with MINIMUM dimensions: 6 km long, cutting

350 m of

strata, and 1 m wide.  For more examples, see, among other papers:

Hurst A. &  Cartwright J. A. Eds. 2007. Sand Injectites:

Implications for

hydrocarbon exploration and production.  Memoir 87 American

Association of

Petroleum Geologists

Hurst A.,  Cartwright J. &  Duranti D. 2003.  Fluidization

structures in

produced by upward injection of sand through a sealing lithology.

In:

Subsurface sediment mobilization (eds. Van Rensbergen P.,Hillis

R.,Maltman

A. J. & Morley,C.K.),  Geological Society Of London, London, 123-127

Jonk R., Hurst A., Duranti D., Mazzini A., Fallick A. E. &  Parnell

J.

2005.The origin and timing of sand injection, petroleum migration

and

diagenesis: the Tertiary petroleum system of the South Viking

Graben, North

Sea. AAPG Bulletin,  89,  329-357

Hurst A. &  Duranti D. 2004. Fluidisation and injection in the deep-

water

sandstones of the Eocene Alba Formation (UK North Sea).

Sedimentology,  51,

3,  503-529

Hope this helps

David Macdonald

-----Original Message-----

From: Tectonics & structural geology discussion list

[mailto:[log in to unmask]] On Behalf Of Eric Essene

Sent: 26 November 2009 07:39

To: [log in to unmask]

Subject: Re: Anderson Stress Meeting: September 2010 reminder

Rob,

 The term igneous intrusions is functionally a terrible term, a

distinction without a difference.  More than 99.9% (or more?) of the

time it means igneous rocks where the term is redundant.  If one

talks

about sedimentary intrusions it is on a meter scale feature,

commonly

even less--I have seen some down to cm scale.  When they formed and

well afterward they did not look like dikes, just fractures filled

with loose sediment.  I discount the poor term "sandstone dikes" as

needing yet another confusing term.

  On the other hand salt domes are metamorphic (recrystallized) but

not molten rock, well a little brine.  They were not in the

sedimentary group during formation.  Yes, we have diapirs of

metamorphic rock, although a lot of those gneiss domes probably

have a

little melt.  I would agree about metamorphic diapirs but simply

would

not call them metamorphic intrusions to avoid confusion on a

transitional rock.  Gneiss domes are a nice description for them.

  It must be exceedingly rare for igneous petrologists/geochemists

to be presenting data on "sand dikes".   Salt domes are much larger

but are as they form. Do you know of any igneous petrologist/

geochemist who would report on them in your symposium?  So

"sandstone

dikes" are fractures filled with loose clastic material and water,

salt diapirs are all metamorphic and may have brine, gneiss domes

are

often partial melts then at least partly igneous, and the term

"igneous intrusion" is clearly redundant to the average passerby.

Is

this really a useful terminology?

cheers,

eric

On Nov 26, 2009, at 12:17 AM, Butler, Robert wrote:

Eric

Actually - there are lots of non-igenous intrusions in basins -

sandstone dykes through 100s metres of strata. Not to mention mud

diapirs, salt etc etc.... gas chimneys....

go google!

Cheers

Rob

________________________________________

From: Tectonics & structural geology discussion list

[[log in to unmask]

] On Behalf Of Eric Essene [[log in to unmask]]

Sent: 26 November 2009 05:09

To: [log in to unmask]

Subject: Re: Anderson Stress Meeting: September 2010 reminder

Rob, Zoe, and all,

Igneous intrusions as opposed to all those sedimentary plutons?

The phrase is nearly always meaningless and should not be used.

Sounds like a great trip.

cheers,

eric

On Nov 25, 2009, at 11:28 PM, Butler, Robert wrote:

Dear all

As we get our diaries together for 2010 we thought it timely to

remind you of the conference next year:

Stress controls on faulting, fracturing and igneous intrusion in

the

Earth's crust

A meeting to commemorate the work of Ernest Masson Anderson on the

50th anniversary of his death.

6-8 September 2010 at the University of Glasgow, UK

Organisers: Zoe Shipton, Rick Sibson, Dave Healy, Rob Butler

We will send out details of the meeting ("First Circular") in

January -

Abstract deadline will be end April with a preliminary programme

drawn up through May.

We are also planning a fieldtrip to the Hebrides and NW Scotland

to

examine a variety of faults and the Tertiary igneous complexes.

Again - further information will be included in the first

circular.

Hope to see a bunch of you in Scotland next September!

Zoe, Rick, Dave and Rob.

The University of Aberdeen is a charity registered in Scotland, No

SC013683..

The University of Aberdeen is a charity registered in Scotland, No

SC013683..

The University of Aberdeen is a charity registered in Scotland, No

SC013683..

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