<< Previous Next >>

Stacks, Dykes and Goodbye New York


Stacks, Dykes and Goodbye New York
Photo Information
Copyright: James Parker (Jamesp) Gold Star Critiquer/Gold Note Writer [C: 1252 W: 0 N: 4834] (14354)
Genre: Landscapes
Medium: Color
Date Taken: 2008-02-18
Categories: Seascape
Camera: Canon EOS 1Ds MkII, Canon 24-70 mm f 2,8 L-USM
Exposure: f/6.3, 1/200 seconds
More Photo Info: [view]
Photo Version: Original Version, Workshop
Date Submitted: 2008-03-11 8:16
Viewed: 831
Points: 50
[Note Guidelines] Photographer's Note
This is the first of two postings I am going to make which will explain the strange title - the Goodbye New York bit.

Madeira is a volcanic island and is made up of basaltic lavas (here orange/red), which have later dykes running through them (here blackish) – the dykes are much harder than the basalt (which is poorly bedded anyway ie not very strong structurally)- this part plays an important role in the second part of the title. The basaltic lavas are eroded much more quickly than the dykes (some sort of dolerite here – probably). On the coast this leaves the dykes standing as stacks after the basalt has been worn away.

DYKES

An intrusive dyke is an igneous mass with a very high aspect ratio, which means that its thickness is usually much smaller than the other two dimensions. Thickness can vary from sub-centimeter scale to many meters and the lateral dimensions can extend over many kilometers. A dyke is an intrusion into an opening cross-cutting fissure, shouldering aside other pre-existing layers or bodies of rock; this implies that a dyke is always younger than the rocks that contain it. Dykes are usually high angle to near vertical in orientation, but subsequent tectonic deformation may rotate the sequence of strata through which the dyke forms/intrudes so that the latter becomes horizontal. Near horizontal or conformable intrusions along bedding planes between strata are called intrusive sills – the Great Whin Sill in N England is a very good example – the Romans made use of it and built part of Hadrian’s Wall on top of it.

Sometimes dykes appear as swarms, consisting of several to hundreds of dykes emplaced more or less contemporaneously during a single intrusive event. The world's largest dyke swarm is the Mackenzie dyke swarm in the Northwest Territories, Canada.

Dykes often form as either radial or concentric swarms around plutonic intrusives, volcanic necks or feeder vents in volcanic cones. The latter are known as ring dikes.

Dykes can vary in texture and their composition can range from diabase or basaltic to granitic or rhyolitic, but on a global perspective the basaltic composition prevails, manifesting ascent of vast volumes of mantle-derived magmas through fractured lithosphere throughout Earth history. Pegmatite dykes are extremely coarse crystalline granitic rocks often associated with late stage granite intrusions or metamorphic segregations. Aplite dikes are fine grained or sugary textured intrusives of granitic composition.

STACKS

A stack is a geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast. Stacks are formed when part of a headland is eroded, leaving a small island. They also form when a natural arch collapses due to sub-aerial processes and gravity. A stack may collapse or be eroded leaving a stump. Stacks form most commonly on chalk cliffs, because of the medium resistance to erosion. Cliffs with weaker rock such as clay tend to slump and erode too quickly to form stacks, while harder rocks such as granite erode in different ways. The sea attacks small cracks and opens them. The cracks then gradually get larger and turn into a small cave. When the cave wears right through the headland, an arch forms. Further erosion causes the arch to collapse. This causes a pillar of hard rock standing away from the coast. This is called a stack. PaulH posted a great examples of chalk stacks a couple of days ago – Chalk and Seas (Here is where I would put a link to Paul’s posting – unfortunately I cannot get them to work – help anyone – please)?
jaycee, boreocypriensis, horia, CeltickRanger, uleko, Necipp, matatur, Juyona, eqshannon, gondox, Gert-Paassen, SelenE, JPlumb, iris, Evelynn, rousettus, albert, cicindela has marked this note useful
Only registered TrekNature members may rate photo notes.
Add Critique [Critiquing Guidelines] 
Only registered TrekNature members may write critiques.
Discussions
ThreadThread Starter Messages Updated
To JPlumb: AnomalyJamesp 1 03-12 01:28
To eqshannon: ThanksJamesp 1 03-12 01:22
To horia: WorkshopJamesp 1 03-11 09:17
You must be logged in to start a discussion.

Critiques [Translate]

  • Great 
  • jaycee Gold Star Critiquer/Gold Note Writer [C: 1778 W: 8 N: 4605] (14893)
  • [2008-03-11 8:41]

Hi James,

A good geology lesson! Wonderful shot of the dykes and stacks - terms I knew nothing about. Fascinating to see them in the blue water. Wonderful colors and details. I must admit I don't get the title.

Jane

Hi James

This is a very beautiful view...and yes, with a rather strange title :)
I love the high POV here and the great POV for these dykes and stalks. The rock formation are indeed rather similar in shape to the ones we see in Paul's posts...by the way, here is a link to the one you are referring to:
(a href="http://www.treknature.com/gallery/photo155511.htm")Paul's post(/a)
(just replace the brackets with the the "arrows" [like so: ) turns into > ]and it should work...if i would have written it correctly you wouldn't have been able to get all of it) :)

Back to the shot now, i love the colors and the great 3D feel of it, but i do think that an ND-grad filter would be very useful in such situations. So, i made a workshop to try and mimic that :) Hope you don't mind...
Even so, it's a gorgeous landscape - a type of photo i hope to take when i come to England and the same Paul has promised to take me to :)

Cheers and TFS
Horia

...there...finally got it (struggled to find an easy way to show you the html coding without actually using it)
Also sent you a mail with it :) (just in case)

Hello James,
Much appreciated for the most useful and informative notes regarding the beautiful image, I do gain a lot of knowledge from this!
a very fine and beauitufl shot with the best exposure and focus!
the colouration is awesome to differentiate the the Dykes and stacks!
a very valueable photo that share
best regards
Tony

  • Great 
  • uleko Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 2459 W: 168 N: 7421] (23442)
  • [2008-03-11 10:40]

Hello James,
I feel quite ignorant here as I've never heard of these kind of dykes before. Thank you for your thorough information! This is a splendid capture of this interesting rock face and stacks together with the lovely blue/turqoise water. Very beautiful and well composed.
Many thanks and regards, Ulla

Hello James, another beautiful landscape superb fine detail with great light which helps bring the detail out. Good contrasty lighting tfs Rgds Necip

A beautiful scene captured expertly James, the explanatory note also very satisfying, like a course in geology my friend, thank you indeed for both of them!
Cheers,
Mehmet

  • Great 
  • nglen Gold Star Critiquer/Gold Note Writer [C: 1989 W: 5 N: 5528] (20896)
  • [2008-03-11 13:02]

Hi James . I like the different colours in the sea around the coast. and also the cliffs. a good seascape of a area not often seen. TFS. interesting notestoo.
Nick..

  • Great 
  • Juyona Gold Star Critiquer/Gold Note Writer [C: 2038 W: 6 N: 2019] (13259)
  • [2008-03-11 15:05]

Hola amigo,
bello paisaje,
excelente pov,
maravilloso trabajo y color...
saludos

My goodness. I know I have said it before but I must repeat.. you are a multi talented and very well traveled photographer. You can move with ease from a scenic image to a geologic image to a mammal..and from one place in the world to another...I really, and I mean this,,,,I REALLY would love to have the chance to do this now with all of my gear....it is so wonderful....and so is this image!
Bob

  • Great 
  • gondox Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 260 W: 58 N: 221] (1133)
  • [2008-03-11 16:33]

Hi James!

Very interesting phenomenon, very well captured!
Love the lights, the details and most of all the pattern of water created probably by a slight wind! TFS

Best regards,
Andor

Hi James,


Great note and i learn a lesson in geology.
Good coastline composition with also a good pov.
Beautiful colors.

regards gert

Hi James,
Splendid shot with lovely and fantastic details my friend. Your note is excelent as usual. I am learning from you a lot thing. TFS.
Cheers,
Bayram

  • Great 
  • SelenE Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 2339 W: 59 N: 3778] (12122)
  • [2008-03-12 0:54]

Hello James,
Very nice capture of this interesting coastline. Details, composition, colors and POV look lovely. TFS
Best wishes,
Selen

Hi James, this is a very good photo with excellent colour and textures to go along with your notes. Having read your notes I find myself scanning the shot for the next dyke to be left stranded as a stack. Based on what I'm reading in your notes though, this feature at Madeira is almost an anomaly, i.e. they may not be all that obvious. I did a search on google and found that we have a couple of Dyke Swarms in Eastern Ontario (where I come from originally) yet I've never heard of them. Very informative post, now you have me waiting for part 2.

Thanks, John

  • Great 
  • PaulH Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 1032 W: 26 N: 2994] (10800)
  • [2008-03-12 2:34]

Hi James,
I think you have caught a much more dramatic coastline here than i have, but i appreicate you mentioning my shot, thanks alot :o)
I think, apart from the obvious grandeur of the rock formations, that its the colours that make this. The dark blues of the deeper water and turquoises of the shallows are beautiful.
A well chosen POV, i think Horia's workshop works well too :o)
Paul
PT :O)

  • Great 
  • joey Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1683 W: 242 N: 5560] (19685)
  • [2008-03-12 2:48]

Hi James,
nice image of this magnificent scene!
The colours of the sea is amazing!
Impeccable clarity and detail.
Nice composition.
Looking forward to the next one!
Cheers,
Joe

  • Great 
  • iris Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 389 W: 40 N: 730] (2302)
  • [2008-03-12 3:38]

HI James
How have you been?
THis is a wonderful landscape shot, with great DoF and PoV.Quite informative notes too.Wonder where you standing to get this shot:)
Well done.
TFS & Cheers

  • Great 
  • gannu Gold Star Critiquer/Gold Note Writer [C: 917 W: 4 N: 2282] (10648)
  • [2008-03-12 10:01]

James, Fantastic view and lovely composition. The POV is very nicely defined in the shot. Ganesh

Gee... what a complex geology lesson. I wish I still had a memory and could absorb it all!! I heard a lecture yesterday on the plans to use the larger basalt flows in the US to sequester carbon dioxide. I think it is just amazing to think that you scientists can figure out things like that! One of the bassalt flows is the Columbia one right near where I live.

This is a nice sharp image James. That is a good lens. I was just playing with a couple of new techniques to even out the slightly OE sky with the rest of the image.

TFS
Evelynn : )

hello James

great Seascape shot of those stacks, excellent POV and framing,
i love to see the sea and his blue colour, lovely luminosity
and excellent sharpness & details of all the image, TFS

Asbed

Hello James
very beautiful scene and its excellent shot. Wonderful composition with great POV and superb colors. I like to read your notes, always informative and nicely prepared. Thanks for sharing. best wishes
Ahmet

  • Great 
  • EOSF1 Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1329 W: 107 N: 4791] (21282)
  • [2008-03-13 4:21]

Fantastic landscape James! Perfect composition and a perfect technique! A really great image, well done!

Mario

Hi James
Beautiful coast with very interesting note
Well done
Albert

  • Great 
  • arfer Gold Star Critiquer [C: 2731 W: 0 N: 0] (0)
  • [2008-03-13 8:40]

Hello James

What a beautiful capture of these formations.The POV is excellent.
Very good clarity and focus.
The lighitng is very good,and the colours are vivid and well saturated.
Your notes are very informative as always.
Great post!
TFS


Rob

Hello James!
This is really interesting seascape picture. I did not know that such type of sea coast can be seen in Portugal. Lovely cliffs strongly scilptured by the sea. I like also colouration of this photo, and interesting note
Friendly yours,
Radomir

Calibration Check
















0123456789ABCDEF