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June 6

Core (geology)

What does core mean in the context of a syncline as in "the core of the syncline"? Core (geology) is no help, that redirects to something completely different. SpinningSpark 12:44, 6 June 2020 (UTC)[reply]

It means the "central part", which is one of the dictionary meanings of core e.g. wikt:Core.Mikenorton (talk) 12:56, 6 June 2020 (UTC)[reply]

I think you probably meant wikt:core, Wikitionary pages are case senstitive. But that's still not a very helpful page, none of the meanings are specific to structural geology and I'm still unclear. "Central part" could mean towards the bottom of the syncline "valley", or it could mean towards the centre of the bedding. Or it could be used in a non-technical sense without a specific meaning. SpinningSpark 16:01, 6 June 2020 (UTC)[reply]

A quick google gave [1]. Bazza (talk) 16:56, 6 June 2020 (UTC)[reply]

Which doesn't actually define it. However, if the youngest rocks are on top, then it has to be the part near the surface -- "towards the bottom of the syncline valley" as Spinningspark says. If you follow the link to "anticline" you see that in an anticline the "core" is on the bottom; so in general it's the part of the formation nearest the center defined by the concentric arcs. But don't follow the link to "core", which gives three definitions and none of them are relevant to synclines! --76.71.5.208 (talk) 22:35, 6 June 2020 (UTC)[reply]

In case of an antiformal syncline, the youngest layer is at the bottom. If you think of the system of layers being locally folded around an imaginary cylinder, then the core is the layer nearest to the cylinder. This works for synformal and antiformal synclines and anticlines. --Lambiam 15:16, 7 June 2020 (UTC)[reply]

Having another go, the core of any fold is the part closest to the fold's axis, which is the central part of the structure - there is no special meaning here. I note that the oilfield glossary page linked above contains an internal link to "core", which doesn't even mention folding when you follow it. We should probably at least mention fold cores in the fold (geology) article. Mikenorton (talk) 20:52, 7 June 2020 (UTC)[reply]

I created a redirect: core (anticline). Ruslik_Zero 05:05, 8 June 2020 (UTC)[reply]

(a) The term applies as well to synclines. (b ) The target of the redirect, Anticline, uses the term but does not explain it. --Lambiam 06:47, 8 June 2020 (UTC)[reply]

It is interesting that our anticline article says "...towards the core and uplifted center..." as if the writer believes these are two different things. SpinningSpark 07:12, 8 June 2020 (UTC)[reply]

It is meaningful to say, "the core consists of sandstone". I am not so certain that can be said about the centre of a fold, which is an imaginary line. --Lambiam 21:50, 9 June 2020 (UTC)[reply]