New Proxy for Recent Hurricane Events Using Stalagmite Stable Isotopes

Using recently developed micro-sampling techniques for stable isotope analyses, we obtained monthly to weekly temporal resolution in a fast growing stalagmite from Belize that recorded the last 3 decades of carbonate deposition. The stable oxygen isotope record (O-18 values) varies at interannual to sub-seasonal scales. The largest variations in O-18 values are interannual (corresponding to El Nino events) and annual (corresponding to the strong wet-dry seasonality of the region). Smaller amplitude O-18 variations related to short-term weather fluctuations are also apparent. Brief, low excursions in O-18 values can be identified with hurricane events that impacted Belize in recent decades. This dataset demonstrates that at least some stalagmites can record measurable, low stable oxygen isotope excursions from individual hurricane rainfall events. The proxy is sensitive to storm intensity and distance of storm track to the cave site. This paleotempestology proxy allows estimates of individual storm rainfall amounts and recurrence interval. Pre-historic hurricane events should be detectable using this technique; however, cave sites and individual stalagmites must be selected carefully to recover samples with measurable hurricane records.