Thanks Eric,
For the benefit of the wider discussion, I think Chris Jackson made a good point there. I did actually mean 'sand injectite', i.e. injection of sediment into overlying sediments, as opposed to clastic or neptunian dykes (or dikes). However, Christine's and Woody's contributions are also interesting, it seems that work on the internal fabrics of these things - whatever you call them - could show something. My particular interest comes from applying AMS to igneous intrusions. As Mads pointed out, there are some striking similarities between the magma and the sediment slurry versions from his work and others including Joe Cartwright. I have found that subtle igneous fabrics (revealed using AMS) show interesting things and often ask very serious questions about accepted emplacement mechanisms.
(shameless promotion time) check out:
http://gsabulletin.gsapubs.org/content/119/11-12/1368.full
and
http://jgs.geoscienceworld.org/cgi/content/abstract/164/1/99
and if you haven't had enough
http://sp.lyellcollection.org/cgi/reprint/302/1/159
(reprint/PDFs on request)
The last two sort of relate back to Rob Butlers initial note about the EM Anderson meeting. We have recently been looking very carefully at some of the classic Tertiary Ring dykes (namely Gullion and Mourne). Brian O'Driscoll and others also published a new model for the Ardnamurcham Great Eucrite http://geology.gsapubs.org/content/34/3/189.full - again from information derived from subtle internal fabrics (from AMS).
Anyway back to injectites - you see where I'm going. The references so far are interesting - thanks all.
Perhaps some of all this could appear at the TSG meeting in January??
http://www.gees.bham.ac.uk/tsg2010.shtml
All the best everyone
Carl
--------------------------------------------------------------------------
Dr Carl Stevenson
Lecturer in Geology
School of Geography, Earth and Environmental Sciences
University of Birmingham
Birmingham, UK
B15 2TT
[log in to unmask]
http://www.gees.bham.ac.uk/staff/stevensonct.shtml
tel: +44 (0) 121 4146136
-----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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