Roger,
I agree completely with your views.
cheers,
eric
On Nov 27, 2009, at 11:18 AM, Musson, Roger M W wrote:
> I have to say that I was using the first thing that popped into my
> head as an example, and having heard basalts sometimes described as
> either mafic or ultramafic, I reckoned it would do, but I nearly
> wrote "green notebooks"; perhaps I should have.
>
> As a seismologist, I wouldn't know a komatiite from a kontikiite.
>
> Roger
>
>> -----Original Message-----
>> From: Tectonics & structural geology discussion list [mailto:GEO-
>> [log in to unmask]] On Behalf Of Eric Essene
>> Sent: 27 November 2009 16:12
>> To: [log in to unmask]
>> Subject: last comment
>>
>> 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..
>>
>>
>>
>>
>>
>>
>>
>> --
>> This message (and any attachments) is for the recipient only.
>> NERC
>> is subject to the Freedom of Information Act 2000 and the
>> contents
>> of this email and any reply you make may be disclosed by NERC
>> unless
>> it is exempt from release under the Act. Any material supplied
>> to
>> NERC may be stored in an electronic records management system.
>>
>>
>>
>>
>
>
> --
> This message (and any attachments) is for the recipient only. NERC
> is subject to the Freedom of Information Act 2000 and the contents
> of this email and any reply you make may be disclosed by NERC unless
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