Agenda

Rhawn Denniston, Geology Department, Cornell College (Iowa)

Abstract:
The Indo-Pacific tropical rain belt represents the region spanned by the seasonal migration of the intertropical convergence zone (ITCZ) between southern Asia and northern Australia. While a large number of studies (most notably from speleothems) have reconstructed Holocene monsoon rainfall variability from the northern and central portions of this region, monsoon dynamics from the southern margin of the tropical rain belt are less well understood. My colleagues and I have developed a high resolution and precisely dated stalagmite record of Australian summer monsoon rainfall over the past 4000 years from cave KNI-51, central Australian tropics. Shifts in rainfall reconstructed here are in phase with those from southern China, revealing a previously unrecognized level of coherence between the two systems, and demonstrating expansion and contraction of the rain belt over multi-decadal time scales.

Bio Sketch:
Prof. Rhawn Denniston received a BA in Geology from Hamilton College (1991), MSc in Earth and Planetary Sciences from the University of New Mexico (1995), and PhD in Geosciences from the University of Iowa (2000). He has been in the Geology Department at Cornell College (Iowa) since 2000 and is now the William Harmon Norton Professor of Geology there, as well as the chair of the Environmental Studies program. His research generally focuses on the use of stalagmites and fossil corals to examine paleoenvironmental change.