University of New Hampshire
Mentor: Dr. William Clyde, Department of Earth Sciences
Using Magnetostratigraphy To Find The Cretaceous- Paleogene Boundary In La Colonia Formation, Patagonia, Argentina
The Cretaceous-Paleogene (K-Pg) boundary marks the occurrence of one of the most important events in Earth’s history. At this time (approximately 66 million years ago), a mass extinction occurred, caused primarily by a meteorite impact. This also caused a change in global climate and widespread deposition of material ejected from the impact crater. Currently, there are few continental records of the K-Pg boundary in South America, resulting in poor understanding of its effects there. Boundary markers include ejecta deposits, high iridium concentration, and tsunami deposits. Another method for finding the boundary uses paleomagnetism (measuring the magnetic polarity of a rock, preserved from when it formed). Earth’s magnetic field has reversed through time, and these reversals can be recorded in rock formations. Chron C29r is an interval of reversed magnetic polarity that encompasses the K-Pg boundary. This project will seek to find Chron C29r in samples taken from La Colonia Formation in Patagonia, Argentina. Samples taken from strata in La Colonia will be analyzed to find their magnetic polarity. This will be done by measuring them with a magnetometer as they are slowly demagnetized. An analysis to find their magnetic mineralogy will also be conducted. Studying the K-Pg boundary in La Colonia Formation will help contribute to understanding of how Earth reacts to cataclysmic events.