Coldwater Cave

Figure 18. An early measurement of luminesoenoe banding using the optical density of photographic film. Coldwater Cave, Iowa. Upper curve shows variation in the luminescent intensity on the scale of thousands of years. Insert curve shows details of resolution at an annual scale. From Shopov et al. (1994).

Figure 2. Co-variations of 6 Cct and 8 Oc, (given relative to the PDB standard) for some fossil speleothems (73951 - Igloo Cave, Nahanni Region, NWT, Canada 72040 - El Sotano de Soyate, SLP, Mexico 71003 — El Sotano de la Tinaja, SLP, Mexico 73039 — Crystal Cave, Bermuda 71042 - El Sotano del Arroyo, SLP, Mexico 74019 - Coldwater Cave, lA, USA) illustrating isotopic relationships that characterize deposition under equilibrium and non-equilibrium situations (from Harmon, 1975). Meaningful paleoclimate information can only be retrieved from speleothem calcite deposited under conditions of isotopic equilibrium.

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