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Silk_Hope_Woodcraft t1_it4nq84 wrote

Reply to comment by Foosh718 in Curiosity Mars Rover Reaches Long-Awaited Salty Region by Pluto_and_Charon

So, if there ever was water/liquid present, wouldn't the time passage of sequential laying of layers happen quickly? (Like ice rings don't count years, but changes in temperature) Aren't we assuming a lot to say these layers represent passage of time?

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Foosh718 t1_it4usx3 wrote

As you say, under some conditions layers are laid down more quickly, and of different materials. Over time different materials also compress to different degrees. All of these conditions leave clues geologists can identify and interpret: "time passage of sequential" layers is still time passage, and additional information about context lets them interpret the scale of that time. (Similarly, tree rings grow at different rates under different conditions, but can be interpreted reliably.)

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