| Summary: | <jats:title>Abstract</jats:title><jats:p>Winter Wonderland Cave contains perennial ice associated with two types of cryogenic cave carbonate (CCC) formed during the freezing of water. CCC<jats:sub>fine</jats:sub> is characterized by relatively high δ<jats:sup>13</jats:sup>C values, whereas CCC<jats:sub>coarse</jats:sub> exhibits notably low δ<jats:sup>18</jats:sup>O values indicating precipitation under (semi)closed-system conditions in a pool of residual water beneath an ice lid. Previous work has concluded that CCC<jats:sub>coarse</jats:sub> forms during permafrost thaw, making the presence of this precipitate a valuable indicator of past cryospheric change. Available geochronologic evidence indicates that CCC formation in this cave is a Late Holocene or contemporary process, and field observations suggest that the cave thermal regime recently changed in a manner that permits the ingress of liquid water. This is the first documented occurence of CCC<jats:sub>coarse</jats:sub> in the Western Hemisphere and one of only a few locations where these minerals have been found in association with ice. Winter Wonderland Cave is a natural laboratory for studying CCC genesis.</jats:p>
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