Talk:Dike (geology)

Youtube Video

When I first read this article, I had no idea what was going on. I have no background in geology, and so all the pictures just look like random pictures of rocks. The captions don't help at all because I can't tell which type is rock A and which type is rock B. The first paragraph of this article is extremely confusing for somebody who is just starting to learn about geological concepts. I think it would be great if there was a schematic diagram here which clearly labelled a dike and a sill and showed it distinct from the surrounding rock. A resource that helped me understand dikes and sills immensely was a YouTube video that I found here: https://www.youtube.com/watch?v=6loGYTCBVqo I'm wondering if it's possible to put this video on the wiki article, or to create a similar video, or to create a schematic similar to the one depicted on it. I feel that this would improve the article's readability, particularly for the layperson. XieChengnuo (talk) 20:57, 10 April 2013 (UTC)

Question

What does "rotate the including sequence" mean? - Chris

Folding or tectonic deformation resulting from plate collisions, orogeny. This does need to be clarified in the article - put it on my to do list (means procrastinate :-) Vsmith 15:22, 15 Apr 2005 (UTC)

Picture

I seriously doubt that it's dike on this picture. Dikes are mainly composed of mafic rocks (basalt, diabase) because only rocks which are low in silica have sufficiently low viscosity to flow in such a narrow cracks. More silicic intrusions have much bigger aspect ratio (ratio of thickness to length). I believe that it's an anatexis (partial melting) on this picture. Siim 17:36, 12 March 2006 (UTC)

Mea culpa. I made a mistake. Most of these white narrow stripes are indeed products of partial melting but wider leucocratic structure seems to be intruded material, it means dike. I asked one experienced petrologist to comment that picture and he made it clear for me. Siim 16:17, 13 March 2006 (UTC)

Volcano

Are dikes a type of volcano?—Preceding unsigned comment added by 209.105.206.130 (talk • contribs) 03:23, 29 July 2007

No, but they are related. An intrusive (i.e. igneous) dike occurs when magma forces apart existing rock along a vertical plane, probably along an existing fault where the rock has been broken in slipping upward or laterally. The dike is the rock resulting when that magma solidified underground. A volcano is an extrusive feature, where magma flows upward and breaks thru to open space (air, water, vacuum on Mercury and moons). Volcanos are typically small rather than long, narrow, openings, presumably because the breakthru at the weakest point relieves the pressure that would be necessary to break thru elsewhere. As lava cools and solidifies near the vent, the volcanic cone of solidified rock builds up, producing a volcanic mountain. Intermediate between igneous dikes and volcanos is a breakthru to the surface all along a fault, with lava spilling out and spreading in a sheet (or two sheets, one on each side of the fault), producing features like the Deccan Traps or the Siberian Traps.
--Jerzy•t 08:19, 30 October 2007 (UTC)

sedimentary dike in permafrost

I disagree with the second mechanism of sedimentary dike formation in the article: "When a soil is under permafrost conditions the pore water is totally frozen. When cracks are formed in such rocks, they may fill up with sediments that fall in from above. The result is a vertical body of sediment that cuts through horizontal layers: a dike."

By this definition any sedimentary infilling of a crack of any kind is a dike, and this definition is too broad. It could include sediment that fills in mudcracks, or even just alluvium filling a slot canyon. The basic concept of a dike is that it intrudes overlying layers from below. If the above definition is in a textbook or article somewhere, please include the citation. Jstuby (talk) 13:27, 26 April 2011 (UTC)

Not helpful

The examples and perspective in this article deal primarily with USA and do not represent a worldwide view of the subject. Please improve this article and discuss the issue on the talk page. (April 2011)

Wow, two for two on the Most Irritating Things About Wikipedia list. First, we have the ignorant nitpicking by people (or bots) who know nothing about a field. Second, we have political correctness at its most ludicrous. Crap like this is EXACTLY why people don't want to contribute to Wikipedia, either with edits or cash.

Geology is concerned with the natural earth, not human-made political borders. The only thing that's important is that the examples are accurate. — Preceding unsigned comment added by 71.119.248.102 (talk) 07:37, 9 January 2012 (UTC)

Seems the lack of references is more important. Vsmith (talk) 10:16, 9 January 2012 (UTC)

I must disagree with the anonymous contributor above who goes rather over the top. An article which deals with a worldwide subject such as dikes/dykes benefits from a worldwide perspective. After all whilst there are similarities between phenomena which are displayed on one part of the Earth, there can also be differences - and casual readers of Wikipedia may be more likely to return if they find examples from their own neck of the woods, be that the nearby town or even simply their own continent. I may get around to adding some useful British material - provided it is accurate and enhances the article, that is! And Vsmith makes a good point too of course. cheers Geopersona (talk) 05:15, 18 July 2013 (UTC)