Palaeoclimatic Significance of Perennial Ice Accumulations in Caves: an Example from Scarisoara Ice Cave, Romania

• Main Author: Persoiu Tiritu, Aurel
• Format: Doctoral or Postdoctoral Thesis
• Language: unknown
• Published: Digital Commons @ University of South Florida 2011
• Subjects: ice caves; stable isotopes; palaeoclimate; Holocene; Europe; American Studies; Arts and Humanities; Climate; Geography; Geology; ice core
• Online Access: https://digitalcommons.usf.edu/etd/3291; https://digitalcommons.usf.edu/context/etd/article/4486/viewcontent/PersoiuTiritu_usf_0206D_10408.pdf

Stable isotopes in ice cores drilled in the polar and high-mountain region have been used intensively to reconstruct past climatic changes and atmospheric dynamics. However, no similar studies have been conducted on perennial ice accumulations in caves due to a limited understanding of the links between the external and cave environments, and the way in which the climatic signal can be recorded by the cave ice. In this thesis, we successfully designed and build a research methodology for the reconstruction of past climatic changes based on perennial ice accumulation in caves, using as example the Scarisoara Ice Cave, Romania. The ice block in this cave preserves a large variety of candidate proxies for both past climate and environmental changes, the most significant ones being the stable isotopic composition of the ice (a proxy for air temperature) and pollen remains. The ice block has formed by the successive accumulation of layers formed by the freezing of water accumulated from late summer through mid-autumn precipitation. An original method has been developed for the reconstruction of the stable isotopic composition of water before freezing, and further, of the late summer air temperature. Pollen in the ice has been found to reflect changes in surface vegetation at both local and regional scale. A 22 m long ice core has been extracted from the ice block, and stable isotope analyses were performed at high resolution on its entire length. Twenty-sex radiocarbon ages have been used to derive a precise depth-age model for this core. The stable isotope data covers almost the entire Holocene, between 0.09 and 9.75 ka BP. The first order fluctuation broadly follows the orbitally induced Northern Hemisphere September insolation, with a minimum in the early Holocene, a slow climb towards a maximum at ~5.0 ka, followed by a very slow cooling towards the present, accentuated after ~0.5 ka. Superimposed on the long-term variations a series of rapid cooling events (RCE) are recorde, the most notable ones being at 9.5 ...