Forms in fractures of rocks already in place, so it an INTRUSIVE featureForm at right angles to the direction of extension in the area - nature’s frac jobsCan be super thin or super thick, but generally are self-consistentCan have multiple periods of injection or even multiple compositions of injection over timeCan get en echelon patterns, rings, and cones (last two common with caldera volcanism)Magmatic are the most well known and form when magma flows into a crack and cools into a sheet.The igneous rock is generally more weathering resistant so we get cool weathering featuresCan be rhyolitic, but mostly basalticRate of cooling determines grainsize (slow = big) and big near the centerCan have columnar jointingBig phenocrysts orient with flow direction - cool! AMS studies show this.These are awesome when you get them radially around a volcano!Horizontal dikes are called sillsClastic dikes are formed by sediments episode 177Can be formed with fluid pressureCracks in permafrost that fill inFun Paper Friday
One plus one equals two, right? Sure, but you won't get published saying it that way.Siegfried, John J. "A first lesson in econometrics." Journal of Political Economy 78.6 (1970): 1378-1379.Contact us:
Support us on Patreon!www.dontpanicgeocast.comSWUNG Slack@dontpanicgeowww.johnrleeman.com@geo_leeman@ShannonDulin
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