Ammonia hydrates and crystalline ice were two items I thought I could use to potentially narrow down or identify the age of the event that created Charon's smooth southern hemisphere. Turns out neither is a reasonable age dating method for this event. Crystalline ice is found on other Kuiper Belts Objects (KBO) of similar size to Charon and the ammonia hydrates are spread across Charon's northern and southern surfaces but not around its trailing hemisphere. If the ammonia was predominately on the southern hemisphere it would suggest the event created the ammonia hydrates. If crystalline water ice were only on Charon it might also point to the event as a cause but neither is correct. Instead the leading hemisphere displaying ammonia indicates Charon's rotational orbit around Pluto is the key factor is the placement of the ammonia.
Zones - Rocky Planets, Main Asteroid Belt, Gas Giants, Kuiper Belt Objects, Transneptunian Objects Rocky Planets - temperature from Sun evaporates away volatiles Main Belt - Frost line, Albedo shift Gas Giants - Centaurs, Trojans Kuiper Belt - Cold Classical Red KBO, Neptune Perturbed (resonant) Multicolored Scattered Disk Objects, Plutinos Transneptunian Objects,