Natisha Alicea is a senior at Carleton College, majoring in Geology. Her research interests include geochronology, particularly as applied to archaeology. Ms. Chu is also an Andrew W. Mellon Mays Fellow and is dedicated to eradicating racial disparities in academia. Jennie plans on pursuing her Masters/Ph.D. in geochronology.
My dream is to be involved in groundbreaking work in the Earth Sciences while being a mentor for underrepresented students in the sciences and in academia.
Evidence for Heat-Treatment of Stone Tools: Magnetic Mineralogy of Heated Chert
Abstract: Intentionally heating a rock can improve its workability for knapping and tool-making purposes, and archaeological artifacts show that this process was commonly employed across the Stone Age world. Insights into this process can help constrain various sociopolitical and environmental behaviors. A previous study on chert has shown that the magnetic properties of heated stones are markedly different than unheated stones; however, this earlier study used heating temperatures that were unattainably high for past toolmakers. The research reported here examines the variability of magnetic properties across a range of heating temperatures that are similar to those used by past knappers. The susceptibility, remanence, and hysteresis parameters for all eleven varieties of chert included in this study changed considerably after five hours heating at various temperatures. In many cases, the mineral hematite (Fe2O3) appears to precipitate during heating, while grains of magnetite (Fe3O4) become progressively more oxidized. Thus, by comparing the magnetic properties of unheated chert to those of a chert artifact from the same geologic source, one should be able to determine whether or not the artifact was heat treated. Ongoing research will examine whether heat-treated cherts are capable of accurately recording the direction and strength of the Earth's magnetic field. Download poster. [PDF]
Dr. Joshua Feinberg is a McKnight Land-Grant Professor of Geology & Geophysics in the Department of Earth Sciences and an Adjunct Professor in the Department of Anthropology at the University of Minnesota. He is also the Associate Director of the Institute for Rock Magnetism, a National Multi-User Facility supported by the National Science Foundation. Feinberg's research aims to apply state-of-the-art magnetic and paleomagnetic technologies to research across a wide range of disciplines, including geoscience, anthropology, planetary geology, material science, physics, biology, and medicine.