New Mexico Geological Society Annual Spring Meeting — Abstracts

Several high-resolution paleoclimatic records spanning the Holocene indicate nearsynchronous millennial-scale climate variability through much of western North America. These records are taken from a variety of environments including a subalpine setting in Yellowstone National Park, an alpine setting in New Mexico and an arid playa system in the Chihuahuan Desert of northern Mexico. High montane lakes and bogs from the Sangre de Cristo Mountains of northern New Mexico record a series of glacial and periglacial events (colder, effectively wetter climates) that alternate with warmer, drier climates. This record spans the late Pleistocene and the Holocene. Forest fire-related sedimentation and alluvial activity from northeast Yellowstone National Park also shows a clear response to millennialscale climate change during the Holocene. Pulses of fire-related debris flow activity occur during warmer, drier periods that are more prone to droughts. These alternate with cooler, effectively wetter conditions producing more river discharge and promote terrace formation through lateral migration of channels. Pluvial lake highstands in northern Mexico documented by constructional beach ridges and freshwater lacustrine fauna occur during cooler and wetter climate conditions and alternate with warmer and drier playa conditions.

Most of the cooler wetter events in each of these records are spaced approximately 1000 to 2000 years apart and correlate in time with each other. They appear to reflect widespread temperature anomalies and to a lesser extent, precipitation anomalies. These cool events also correlate with episodes of widespread cooling in the North Atlantic Ocean suggesting that millennial-scale climate changes are at least hemispheric in extent during much of the Holocene.