Once upon a time, MOH and I left suddenly for an unexpected trip of unknown time duration, and I failed to empty all the coffee cups. Upon arriving back, having been gone most of 14 days, I tentatively looked in my cup expecting to find terrible mold, instead finding these lines of coffee deposited around the side of the cup.
"Varves!" I exclaimed, "Except they aren't from yearly deposits, they're from daily deposits!"
I've reflected a little, and asked a few close-at-hand sources, and decided these aren't really varves — and they probably aren't really rhythmites, either — for the simple reason that varves and rhythmites would be layers, of concentrated coffee in this case, that would have been deposited in the bottom of the cup. Instead, these must be more akin to strandlines — or shorelines around a coffee lake, in this case — as suggested by @GeoTheoBO. Other suggestions for what to call these deposits were Stratified Caffineite (@CGKings317), rhythmites (@alexbirtwisle), and my favorite, "Jarves" from "Java-varves" (@Dhunterauthor). Everyone else is welcome to jump into this discussion and naming exercise in the comments.
Prior to deciding that these were really the results of daily evaporation of coffee, I did count the rings. There are 13, with a possible incipient 14th one near the bottom representing the partial 14th day during which we arrived back in time to check the cup. The lines I've drawn above are based not just on the locally fuzzy record shown in that one photo, but on the three photos I took documenting the entire stratigraphic record around the entire inner part of the cup.
Here are the final determinations. A few of the days are a little fuzzy and the lines have been brought in from the side, just like you might have to do when correlating deposits out in the field. Most day's deposits are light toward the bottom and darken upward, possibly reflecting something having to do with diurnal temperature and humidity variations. To be honest, I don't really know when the darkest portion of each day's ring forms, whether at night, during the day, or at some other time. The cup was sitting on the kitchen counter in the sunlight of the window the entire time we were gone; evaporation would presumably have been strongest during the daylight hours, possibly resulting in the lower, lighter colored part of the layer. Any other thoughts?
This post has been submitted to the Bake-Sale Accretionary Wedge (AW#30), though no baking was involved.
UPDATE: Accretionary Wedge #30: the Bake Sale is now up at Mountain Beltway. It's a very yummy Wedge, I might add.