Talk:Isograd

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Plane of . . .[edit]

I'm not a geologist, but in the opening definition "surface" seems more likely than "plane". Normally in scientific usage a plane is flat. Musiconeologist (talk) 17:31, 25 August 2021 (UTC)[reply]

Update: The OED definition uses surface as do all its examples, so I've now changed it.Musiconeologist (talk) 18:16, 25 August 2021 (UTC)[reply]

References in introduction[edit]

I've made the first paragraph more explanatory using information from the articles for the various technical terms it uses. But I had to keep its three references together at the end, as I don't have access to the books. I think it would be sensible to check whether they can now be moved to the specific points where they're relevant. Musiconeologist (talk) 22:32, 25 August 2021 (UTC)[reply]

Lines on maps of metamorphic terranes[edit]

There are several issues with the second paragraph of the article as it stands. Safely fixing them requires more knowledge of geology than I have.

Metamorphic terranes: This needs a link, but the Terrane article appears to be about a different usage of the term so either is not the appropriate place, or needs clarifying so that it is.
(or landscapes underlain by metamorphic rocks): unclear whether this is an explanation (that is, . . .) or an alternative (or of . . .)
An isograd has just been defined as a surface, but now refers to a line.
the first occurrence of garnet is confusing. First in what respect? Presumably as one moves across the map into a region containing garnet, and then other index minerals, but on first reading I imagined moving vertically into the rock until one finds garnet, then somehow relating this to a line on the map. I think something like the garnet isograd represents the boundary between areas which do and do not contain garnet would be better.

I'd like to add a sentence immediately after the existing definition similar to one of the following, but worded so as to accurately represent the usage within geology:

The line where this surface and the upper surface of the bedrock intersect is also commonly referred to as an isograd.
The line where this surface intersects a horizontal section through the rock is also commonly called an isograd.

Alternatively I could just trust the OED definition and change surface to surface or line in the first paragraph, though this would be slightly less specific about what the line on a map represents.

Musiconeologist (talk) 18:01, 26 August 2021 (UTC)[reply]