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Labels: england, northern ireland, republic of ireland, scotland, structure

I found this image the other day on Geoff Lloyd's research homepage:



A couple of weeks back, I showed you another image depicting structural geology in the British Isles: the gorgeous hand-drawn diagram by Voll (1960). There are some differences between these two similar diagrams. As an exercise in thinking about how to depict rock structures on the two-dimensional space of paper or computer screens, I think they are worth taking a few moments to examine. Let's compare and contrast...

Similarities:

• Similar perspective (block diagram with the "front" at lower-left).
• Diagram is drawn with the short end along the strike of the structures, and the bulk of the diagram across strike.
• Both depict structurally complex rocks that vary across strike.
• Both use landmarks to give the reader perspective on where on the land's surface these subterranean structures are changing from one motif to another.
• Both are isometric, with the horizontal scale of the block being equal to the vertical scale.

Differences:

• This one was drawn by computer; Voll's was by hand.
• This one is in color; Voll's was in black and white.
• Voll's was generalized to show variations in rock fabric over a large distance; this one is reflective of specific localized data. (I like how it even side-steps a short distance where it apparently wasn't physically possible to go completely perpendicular to strike; see for instance the short jump at the Maer Anticline, and another larger jump at marker 0740 on the scale.) Voll's diagram, in contrast, smooths out those particular rough spots in the data to produce a seamless "summary."
• Voll's was one long wedge; the one is even longer, and as a result has been split into three separate views that are graphically stacked but connected with dotted line, so you can display them in a square- or retangular-shaped space, but can follow along with the overall story from "front" to "back." I think this is a good compromise, graphically speaking.
• Voll's showed the upper and side-facing-us views of the rock units; while this one shows the lower and side-facing-away-from-us views of the rock units, with occasional structures projected out into space between them to show their three-dimensional shapes.

Other thoughts? Observations about these two gorgeous depictions summarizing countless hours of field work? I like rock art; and thinking about rock art -- If you have thoughts, please share them in the comments area below.

I'd like to point out that some other informative sketches have been popping up elseswhere in the geoblogosphere lately: See (in chronological order): here, here, here, here, here and here.

Labels: art, england, structure