We have focused on the Gulf of Mexico because these sediments preserve a record of North American climate change. Periods of intense freshwater runoff following the last ice age are preserved in Gulf of Mexico sediments. Likewise, extended episodes of flooding and drought are recorded in river flow data during the last century and similar events throughout the Holocene should be recorded in high accumulation rate sequences in the Gulf of Mexico. An annual summer monsoon is responsible for wet conditions in parts of the south from New Mexico to Florida. Variability in monsoon strength should be recorded in the planktic foraminiferal assemblages from the western Gulf of Mexico.
Many techniques exist to extract paleoclimate information from marine sediments.
This work is one component of the USGS effort to develop a robust and well-dated planktic foraminifer calibration data set.